# Patent

## Title
Lithium ion secondary battery and manufacturing method therefor

## Abstract

Active material particles of a lithium ion secondary battery includes at least a first lithium-nickel composite oxide: LixNi1-y-zCoyMezO2 (where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca) forming a core portion thereof. The surface layer portion of the active material particles includes nickel oxide having the NaCl-type crystal structure or a second lithium-nickel composite oxide, and further includes element M not forming the crystal structure of the first lithium-nickel composite oxide. Element M is at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn.

## Background
RELATED APPLICATIONS
This application is the U.S. National Phase under 35 U.S.C. §371 of International Application No. PCT/JP2006/305730, filed on Mar. 22, 2006, which in turn claims the benefit of Japanese Application No. 2005-084445, filed on Mar. 23, 2005, the disclosures of which Applications are incorporated by reference herein.
TECHNICAL FIELD
The present invention relates to a lithium ion secondary battery that is excellent in safety at the time of an internal short-circuit.
BACKGROUND ART
Lithium ion secondary batteries, a typical example of non-aqueous electrolyte secondary batteries, have high electromotive force and high energy density. Thus, demand is growing for lithium ion secondary batteries, as a main power source for mobile telecommunication devices and mobile electronic devices. A majority of lithium ion secondary batteries currently on the market include a lithium composite oxide containing cobalt as its main component (for example, LixCoO2 (x changes based on charging and discharging of the battery)) as the positive electrode active material. However, cost reduction is difficult because of the high price of cobalt compound used as the raw material in lithium composite oxide containing cobalt as a main component.
Therefore, in view of cost reduction, there have been researches and developments for an alternative to lithium composite oxide containing cobalt as a main component. Particularly, active researches have been carried out for lithium composite oxide containing nickel as a main component (for example, LixNiO2 (x changes based on charging and discharging of the battery)).
In addition to cost reduction, it is important to increase reliability of lithium ion secondary batteries. The lithium composite oxide including Co or Ni produces high valence, highly reactive Co4+ or Ni4+ upon charging. This accelerates electrolyte decomposition reaction involving lithium composite oxide under high temperature environment. As a result, gas generation occurs, and it becomes difficult to curb heat generation at the time of an internal short-circuit.
In charged batteries, LixNiO2 is more reactive than LixCoO2. Thus, curbing of the electrolyte decomposition reaction has been examined. For example, there has been proposed that nickel oxide with the nickel oxidation number of 3 or less and not including lithium in its crystal is added to the lithium composite oxide containing nickel as its main component (Patent Document 1). Additionally, there has been proposed that a coating comprising a specific metal oxide is formed on the positive electrode active material surface (Patent Documents 2 to 5). Further, there have been proposed that the positive electrode active material surface is reduced (Patent Document 6). For example, there has been proposed that the positive electrode active material surface is reduced with gas and the positive electrode active material is mixed with carbon and then baked.
Patent Document 1:
Japanese Laid-Open Patent Publication No. Hei 7-134985
Patent Document 2:
Japanese Laid-Open Patent Publication No. Hei 8-236114
Patent Document 3:
Japanese Laid-Open Patent Publication No. 2003-123750
Patent Document 4:
Japanese Laid-Open Patent Publication No. Hei 11-16566
Patent Document 5:
Japanese Laid-Open Patent Publication No. 2001-256979
Patent Document 6:
Japanese Laid-Open Patent Publication No. Hei 10-199530
DISCLOSURE OF INVENTION
Problem that the Invention is to Solve
As mentioned above, there have been many proposals for curbing gas generation. However, for securing battery reliability sufficiently, the reaction involving lithium composite oxide has to be curbed to a further high degree. To be specific, prevention of battery abnormal heat generation upon internal short-circuit is desired. For example, it is desired to curb battery abnormal heat generation at the time of crush test under environment of 60° C. In view of this, there is still room for improvement in techniques in Patent Documents 1 to 6.
Reasons for the occurrence of abnormal heat generation in battery at the time of an internal short-circuit is described here.
When an internal short-circuit occurs, Joule heat is generated at the short circuit portion. That heat induces thermal decomposition reaction of the positive electrode active material and reactions between the active material and the electrolyte. These reactions involve heat generation. Therefore, when these reactions cannot be curbed, it leads to abnormal heat generation in a battery.
Thermal decomposition reaction of the active material is oxygen desorption reaction from the active material surface. Electrolyte decomposition reaction is a reaction between the active material surface and the electrolyte. As a result of various examinations, there have been obtained findings that these reactions advance at active points of the active material surface. The active point of the active material surface is formed by lattice defect.
According to Patent Document 1, a nickel oxide with nickel oxidation number of three or less and not including lithium in its crystal works to curb electrolyte decomposition reactions. However, merely adding the nickel oxide to the active material leaves the active point on the active material surface existed. Thus, when the crush test is carried out under a harsh environment of 60° C., there is a possibility that battery abnormal heat generation is caused.
According to Patent Documents 2 to 5, a metal oxide film formed on the active material surface can curb the reaction between the active material surface and the electrolyte. However, the active point on the active material surface is not completely inert. Thus, oxygen desorption of the active material cannot be curbed.
According to Patent Document 6, by reducing the whole active material surface, reactivity of the whole surface declines. Thus, thermal decomposition reaction of the positive electrode active material and reaction between the active material and the electrolyte can be curbed. However, a problem occurs in which high-rate performance cannot be obtained sufficiently at low temperature.
Means for Solving the Problem
The present invention aims to further improve safety at the time of an internal short-circuit in a lithium ion secondary battery including a lithium composite oxide (lithium-nickel composite oxide) which contains nickel as its main component and has a crystal structure of for example R3-m as the positive electrode active material, without hindering high-rate performance at low temperature.
That is, the present invention relates to a lithium ion secondary battery comprising a positive electrode capable of charging and discharging, a negative electrode capable of charging and discharging, and a non-aqueous electrolyte;
the positive electrode including active material particles;
the active material particles including at least a first lithium-nickel composite oxide forming a core portion thereof;
the first lithium-nickel composite oxide being represented by LixNi1-y-zCoyMexO2 
where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca;
a surface layer portion of the active material particles including:
(i) at least one selected from the group consisting of a nickel oxide having a NaCl-type crystal structure and a second lithium-nickel composite oxide including a domain having the NaCl-type crystal structure; and
(ii) element M not incorporated in the crystal structure of the first lithium-nickel composite oxide, element M being at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn.
The nickel oxide having the NaCl-type crystal structure is preferably at least one selected from the group consisting of NiO and cation-deficient Ni1-δO. Also, the domain having the NaCl-type crystal structure is preferably structured so that Li in Li site in the first lithium-nickel composite oxide is replaced with Ni, Co, or Me.
In one embodiment of the present invention, element M is distributed more in the outer side of the surface layer portion than in the inner side, and nickel oxide is distributed more in the inner side of the surface layer portion than in the outer side.
In one embodiment of the present invention, the above general formula satisfies 0<z≦0.5, and the concentration of element Me is higher in the proximity of the surface layer portion of the active material particles compared with the inner side thereof.
The amount of element M is preferably 2 mol % or less relative to the lithium-nickel composite oxide.
The present invention also relates to a method for producing a lithium ion secondary battery, the method comprising the steps of:
obtaining a positive electrode capable of charging and discharging;
obtaining a negative electrode capable of charging and discharging; and
assembling a battery including the positive electrode, the negative electrode, and a non-aqueous electrolyte:
the step of obtaining the positive electrode including:
(i) allowing a first lithium-nickel composite oxide represented by LixNi1-y-zCoyMezO2 
where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca to carry at least one element M selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn;
(ii) producing NiOOH on the surface of the first lithium-nickel composite oxide by moisture in the atmosphere by allowing the first lithium-nickel composite oxide carrying element M to stand under an environment with a temperature of 60° C. or less and a humidity of 20% or more;
(iii) preliminary baking the first lithium-nickel composite oxide with NiOOH produced on the surface thereof in a dry air atmosphere, and then carrying out a main baking in an oxygen atmosphere, thereby converting NiOOH into at least one selected from the group consisting of NiO having a NaCl-type crystal structure, cation-deficient Ni1-δO having the NaCl-type crystal structure, and a second lithium-nickel composite oxide including a domain having the NaCl-type crystal structure, to obtain active material particles; and
(iv) forming a positive electrode including the active material particles.
EFFECTS OF THE INVENTION
Based on the present invention, safety at the time of an internal short-circuit can be improved than before in a lithium ion secondary battery including a lithium composite oxide containing nickel as its main component (a first lithium-nickel composite oxide) as the positive electrode active material, without obstructing high-rate performance at low temperature.
The reasons that a high degree of safety can be secured at the time of an internal short-circuit have been only confirmed phenomenologically at this point. By adding element M to the surface of the first lithium-nickel composite oxide and exposing it to an environment satisfying predetermined conditions, only the active point of side reaction is converted into a second lithium-nickel composite oxide including NiO having the electrochemically inactive NaCl-type crystal structure, cation-deficient Ni1-δO having the NaCl-type crystal structure, or a domain having the NaCl-type crystal structure. The side reaction includes oxygen desorption reaction of the first lithium-nickel composite oxide and electrolyte decomposition reaction. Since only the side reaction active point of the surface layer portion of the active material particles is converted into electrochemically inactive oxide, decline in high-rate performance at low temperature is curbed.
It is difficult at this point to clearly analyze in what form element M (at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn) is contained at the surface layer portion of the active material particles. However, it is possible to distinguish, for example, Al, Mn, or Mg present at the surface layer portion, from Al, Mn, or Mg included in the crystal of the first lithium-nickel composite oxide by analysis such as electron diffraction measurement and EXAFS. In analysis, these can be distinguished by its crystal structure. The presence of element M at the surface layer portion of the active material particles can also be confirmed by analysis method such as element mapping by EPMA (Electron Probe Micro-Analysis).



BRIEF DESCRIPTION OF DRAWINGS
[FIG. 1] A schematic cross sectional view of an example of an active material particle of the present invention.
[FIG. 2] A vertical cross section of a cylindrical lithium ion secondary battery of Example of the present invention.



BEST MODE FOR CARRYING OUT THE INVENTION
A positive electrode of the present invention is described first. The positive electrode includes active material particles as described below.
The active material particles include a first lithium-nickel composite oxide. The first lithium-nickel composite oxide may be in any form without limitation. The first lithium-nickel composite oxide may form active material particles, for example, with its primary particles and with secondary particles. The average particle size of the active material particles is preferably 1 to 30 μm, for example, without any limitation.
The first lithium-nickel composite oxide is represented by the general formula:

LixNi1-y-zCoyMezO2 

where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca. The first lithium-nickel composite oxide may include, as element Me, any of Al, Mn, Ti, Mg, and Ca, singly or in combination of two or more.

The value of x increases and decreases within the above range by battery charging and discharging. Co is an essential component, which gives an effect of decreasing the irreversible capacity to the first lithium-nickel composite oxide. Element Me is an arbitrary component which gives an effect of improving thermal stability to the first lithium-nickel composite oxide. When y or z exceeds 0.5, sufficient capacity cannot be obtained. Also, when y+z exceeds 0.75, the amount of Ni becomes below 0.25. Thus, it becomes difficult to produce NiOOH, NiO, Ni1-δO, or a second lithium-nickel composite oxide including a domain having the NaCl-type crystal structure.
In view of achieving both battery performance and safety, the ranges of y and z are preferably 0.05≦y≦0.25 and 0.001≦z≦0.1, respectively, and further preferably 0.08≦y≦0.2 and 0.005≦z≦0.05, respectively.
The first lithium-nickel composite oxide is synthesized by baking a raw material having a predetermined metal element ratio in an oxidizing atmosphere. The raw material includes lithium, nickel, cobalt, and element Me, i.e., an arbitrary component. The raw material includes oxides, hydroxides, oxyhydroxides, carbonates, nitrates, and organic complex salts of each metal element. These may be used singly, or may be used in combination of two or more.
In view of making the synthesizing of the first lithium-nickel composite oxide easy, the raw material preferably includes a solid solution containing a plurality of metal elements. The solid solution including a plurality of metal elements may be oxides, hydroxides, oxyhydroxides, carbonates, nitrates, and organic complex salts. For example, a solid solution including Ni and Co, a solid solution including Ni and element Me, a solid solution including Co and element Me, and a solid solution including Ni, Co, and element Me are preferably used.
Baking temperature and oxygen partial pressure of the oxidizing atmosphere for the raw material depend on the composition, amount, and synthesizing device of the raw material. Those skilled in the art can select appropriate conditions as appropriate.
An element other than Li, Ni, Co, and element Me is sometimes mixed in as impurities in a range of amount usually included in industrial raw materials. However, the impurities may not affect the present invention greatly.
The surface layer portion of the active material particles includes at least one selected from the group consisting of nickel oxide having the NaCl-type crystal structure and a second lithium composite oxide including a domain having the NaCl-type crystal structure. Nickel oxide having the NaCl-type crystal structure is preferably at least one selected from the group consisting of NiO and cation-deficient Ni1-δO. The surface layer portion may include any one of NiO, cation-deficient Ni1-δO, and a second lithium-nickel composite oxide, singly or in combination of two or more.
Presence of NiO and cation-deficient Ni1-δO may be confirmed by X-ray diffraction measurement (XRD) and XENES measurement. The second lithium-nickel composite oxide including the domain having the NaCl-type crystal structure may be confirmed by electron diffraction measurement.
δ preferably satisfies 0≦δ≦0.1. In the following, nickel oxide of at least one selected from the group consisting of NiO and cation-deficient Ni1-δO is also called Ni1-δO (0≦δ).
When the amount of Ni1-δO(0≦δ) or the domain having the NaCl-type crystal structure is excessively small to the extent that its presence cannot be confirmed, sometimes the effects of curbing oxygen desorption reaction of the first lithium-nickel composite oxide and reaction between the first lithium composite oxide and electrolyte become insufficient.
The surface layer portion of the active material particles further includes at least one element M selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn. The surface layer portion may include the above element singly as element M, or a plurality of the above elements may be combined arbitrary. Element M contributes to deactivation of side reaction active point of the first lithium-nickel composite oxide. Element M is preferably present at the surface layer portion of the active material particles as oxides. Also, element M is preferably deposited, attached, or carried at the first lithium-nickel composite oxide surface as oxides.
Sometimes the surface layer portion of the active material particles include at least one selected from the group consisting of Al, Mn, and Mg as element M, and the lithium composite oxide includes at least one selected from the group consisting of Al, Mn, and Mg as element Me. In this case, Al, Mn, and Mg as element M contributing to deactivation of side reaction active point of the lithium composite oxide is different from Al, Mn, and Mg as element Me forming lithium composite oxide in the crystal structure. Therefore, these can be clearly distinguished.
However, there may be a case where Al, Mn, and Mg at the surface layer portion diffuse into the first lithium-nickel composite oxide inside the active material particles. That is, there may be a case in which element M at the surface layer portion changes into element Me forming the first lithium-nickel composite oxide. In this case, an Al, Mn, or Mg concentration in the first lithium-nickel composite oxide becomes high in the proximity of the surface layer portion compared with the inner portion of the active material particles.
FIG. 1 is a schematic cross sectional view of an example of an active material particle 10.
The active material particle 10 includes at least a first lithium-nickel composite oxide 11 forming a core portion thereof, and a surface layer portion 12 existing at a surface of the first lithium-nickel composite oxide 11. An oxide of element M 13 is attached to a surface of the first lithium-nickel composite oxide 11. Nickel oxide having the NaCl-type crystal structure or a second lithium-nickel composite oxide 14 is formed mainly at an inner side of the oxide of element M 13. That is, the oxide of element M 13 mainly forms the outer side of the surface layer portion 12, and nickel oxide or the second lithium-nickel composite oxide 14 mainly forms the inner side of the surface layer portion 12.
The first lithium-nickel composite oxide 11 forming the core portion of the active material particle 10 may be primary particles, or may be secondary particles formed by the aggregation of a plurality of the primary particles. Also, a plurality of the active material particles 10 may be aggregated to form the secondary particles.
For the raw material for element M included in the surface layer portion of the active material particles, sulfates, nitrates, carbonates, chlorides, hydroxides, oxides, and alkoxides are preferably used. These may be used singly, or may be used in combination of two or more. Among these, sulfates, nitrates, chlorides, or alkoxides are preferably used particularly, since Ni1-δO (0≦δ) and the second lithium-nickel composite oxide are easily produced at the surface layer portion.
The amount of element M included in the active material particles is preferably 2 mol % or less relative to the first lithium-nickel composite oxide (when x=1, Li in the first lithium-nickel composite oxide). When the amount of element M exceeds 2.0 mol %, there may be a case where the active material surface is excessively covered with the oxide not contributing to reactions, declining high-rate performance at low temperature. Element M may be used in small amount, but preferably element M is 0.01 mol % or more, and further preferably 0.1 mol % or more relative to the first lithium-nickel composite oxide.
An example of a method of manufacturing a positive electrode is described next. First, a case in which Ni1-δO (0≦δ) is produced at the surface layer portion of the active material particles is described. In this case, side reaction active point of the first lithium-nickel composite oxide involved with oxygen desorption and electrolyte decomposition is converted to Ni1-δO (0≦δ).
(i) First Step
First, element M of at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn is carried on a first lithium-nickel composite oxide represented by the general formula LixNi1-y-zCoyMezO2(x≦1.02). The average particle size of the first lithium-nickel composite oxide is not particularly limited, but preferably, for example, 1 to 30 μm.
The method for allowing the first lithium-nickel composite oxide to carry element M is not particularly limited. For example, a raw material for element M is dissolved or dispersed in a liquid component, to prepare a solution or a dispersion. For the raw material of element M, sulfates, nitrates, carbonates, chlorides, hydroxides, oxides, and alkoxides including element M are used. The obtained solution or dispersion is mixed with the first lithium-nickel composite oxide, and afterwards, the liquid component is removed.
The liquid component for dissolving or dispersing the raw material of element M is preferably an organic solvent, though not particularly limited. For example, ketones such as acetone and methylethylketone (MEK), ethers such as tetrahydrofuran (THF), and alcohols such as ethanol are preferable. An alkaline water of pH 10 to 14 is also preferably used.
After introducing the first lithium-nickel composite oxide to the obtained solution or dispersion, the mixed solution is stirred. At that time, the temperature in the liquid is preferably set to for example 80 to 150° C., to easily advance the reaction. Although the stirring time is not particularly limited, for example, 3 hours is sufficient. The method for removing the liquid component is not particularly limited, but the drying is carried out for example at a temperature of about 100° C. for 2 hours.
(ii) Second Step
Next, the first lithium-nickel composite oxide carrying element M is allowed to stand under an environment with a temperature of 60° C. or less and a humidity of 20% or more, preferably for 2 to 48 hours. For example, the first lithium-nickel composite oxide carrying element M is allowed to stand under an environment with a temperature of about 25° C. and a humidity of about 55% for about 24 hours. During this time, NiOOH is produced by moisture in the atmosphere at the surface of the first lithium-nickel composite oxide. At that time, moisture is chemisorped to the side reaction active points at the first lithium-nickel composite oxide surface on a priority basis. Therefore, the side reaction active points can be converted to NiOOH on a priority basis.
There is a possibility that portions other than the side reaction active points are also converted to NiOOH when the humidity is excessively high, or the temperature is high, i.e., exceeding 60° C., in the environment where the first lithium-nickel composite oxide carrying element M is allowed to stand. Allowing to stand for an excessively long period of time also causes the same result. In this case, sufficient charge and discharge capacity may not be secured. Preferable temperature for the environment for allowing the first lithium-nickel composite oxide carrying element M to stand is 10 to 55° C., and preferable humidity is 25 to 60%.
(iii) Third Step
The first lithium-nickel composite oxide with NiOOH produced on the surface thereof is preliminary baked in dry air, and then baked in an oxygen atmosphere. By such baking, NiOOH is converted to Ni1-δO (0≦δ). The baking conditions are not particularly limited, as long as NiOOH is reduced to Ni1-δO (0≦δ) under such conditions. The produced Ni1-δO (0≦δ) forms the surface layer portion of the active material particles along with element M. Element M is usually converted to oxide by baking. Ni1-δO (0≦δ) is made by partially converting nickel of the first lithium-nickel composite oxide. Therefore, Ni1-δO (0≦δ) is distributed to the inner side of the surface layer portion, and oxide of element M is distributed to the outer side.
When element M is not present at the first lithium-nickel composite oxide surface, upon converting NiOOH to Ni1-δO (0≦δ), portions other than the side reaction active points are also deactivated. Therefore, the active material particles with sufficient capacity cannot be obtained. That is, element M works to stabilize the first lithium-nickel composite oxide, and to curb a modification thereof. Upon converting NiOOH to Ni1-δO (0≦δ), water is thought to be released. Element M is thought to curb deterioration of the first lithium-nickel composite oxide by the released water.
An example of baking conditions is described in the following.
Baking of the first lithium-nickel composite oxide with NiOOH produced on the surface thereof is preferably carried out by the following three steps, in view of reliably converting the side reaction active points to Ni1-δO (0≦δ).
First, the first lithium-nickel composite oxide with NiOOH produced on the surface thereof is baked at 300 to 450° C. for about 2 to 24 hours (preferably for 6 hours) in a dry air atmosphere. At this time, the humidity of the dry air atmosphere is preferably 2 to 19%, and the pressure is preferably 101 to 50 KPa.
Then, the baking is carried out at 650 to 750° C. for 2 to 24 hours (preferably for 6 hours) under an oxygen atmosphere. At this time, the pressure of the oxygen atmosphere is preferably 101 to 50 KPa. Afterwards, annealing is further carried out at a temperature of 300 to 500° C., preferably at about 400° C. under an oxygen atmosphere. At this time, the pressure in the oxygen atmosphere is preferably 101 to 50 KPa. The oxygen atmosphere may include components other than oxygen, for example, moisture. However, the oxygen partial pressure is preferably 20% or more (when the pressure in the oxygen atmosphere is set as P and the oxygen partial pressure is set as Po, 0.2≦Po/P≦1).
(iv) Fourth Step
A positive electrode is formed by using the active material particles. The method for making the positive electrode is not particularly limited. Generally, the positive electrode is made by allowing a strip-like positive electrode core material (positive electrode current collector) to carry a positive electrode material mixture including active material particles and a binder. To the positive electrode material mixture, an additive such as a conductive material may also be included as an arbitrary component. A paste is prepared by dispersing the positive electrode material mixture in a liquid component, and the paste is applied on the core material and dried, to allow the core material to carry the positive electrode material mixture.
Described next is a case where a second lithium-nickel composite oxide including a domain having the NaCl-type crystal structure is produced on the surface layer portion of the active material particles.
(i) First Step
A first lithium-nickel composite oxide is allowed to carry element M by carrying out operations in the same manner as the case where the side reaction active points are converted to Ni1-δO (0≦δ), except that the first lithium-nickel composite oxide represented by the general formula LixNi1-y-zCoyMexO2 (1.03≦x) is used.
(ii) Second Step
Operations are carried out in the same manner as the case where the side reaction active points are converted to Ni1-δO (0≦δ), to convert the side reaction active points of the first lithium-nickel composite oxide to NiOOH.
(iii) Third Step
The first lithium-nickel composite oxide with NiOOH produced on the surface thereof is baked. By this baking, NiOOH reacts with surplus Li in the first lithium-nickel composite oxide. At that time, a second lithium-nickel composite oxide including a domain having the NaCl-type crystal structure is produced.
The baking conditions are not particularly limited, as long as NiOOH and surplus Li are reacted under such conditions. The produced second lithium-nickel composite oxide forms the surface layer portion of the active material particles along with element M. Element M is usually converted to oxide by baking. The second lithium-nickel composite oxide is made by partially converting the first lithium-nickel composite oxide. Therefore, the second lithium-nickel composite oxide is distributed to the inner side of the surface layer portion, and oxide of element M is distributed to the outer side.
Similarly to the case where the side reaction active points are converted to Ni1-δO (0≦δ), when element M is not present at the first lithium-nickel composite oxide surface, upon converting NiOOH to the second lithium-nickel composite oxide, portions other than the side reaction active points are also modified to the second lithium-nickel composite oxide. Therefore, the active material particles with sufficient capacity cannot be obtained.
An example of baking conditions is described in the following.
The first lithium-nickel composite oxide with NiOOH produced on the surface thereof is baked for 2 to 24 hours (preferably for 6 hours) at 400 to 750° C. under an oxygen atmosphere. At this time, the pressure of the oxygen atmosphere is preferably 101 to 50 KPa. The oxygen atmosphere may include components other than oxygen, for example, moisture. However, the oxygen partial pressure is preferably set to 20% or more (when the pressure of the oxygen atmosphere is set to P, and the oxygen partial pressure is set to Po, 0.2≦Po/P≦1).
(iv) Fourth Step
A positive electrode is made by carrying out operations in the same manner as the case where the side reaction active points are converted to Ni1-δO (0≦δ).
Elements such as Mg, Ti, Nb, and Ca are generally known to improve battery performance, reliability, and safety. Therefore, elements such as Mg, Ti, Nb, and Ca are preferably incorporated into the first lithium-nickel composite oxide to form a solid solution.
For the binder to be included in the positive electrode material mixture, a thermoplastic resin is preferable, although any of the thermoplastic resin and a thermosetting resin may be used. For the thermoplastic resin that can be used as the binder, for example, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrenebutadiene rubber, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethylvinylether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, and ethylene-methyl methacrylate copolymer may be mentioned. These may be used singly, or may be used in combination of two or more. These may be crosslinked by ions of, for example, Na.
Any conductive material may be included in the positive electrode material mixture, as long as the material is an electron conductive material that is chemically stable in the battery. For example, graphites such as natural graphite (flake graphite) and artificial graphite; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powder such as aluminum powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxide such as titanium oxide; an organic conductive material such as polyphenylene derivative; and carbon fluoride may be used. These may be used singly, or may be used in combination of two or more. The amount of the conductive material to be added is not particularly limited, but preferably is 1 to 50 wt %, further preferably 1 to 30 wt %, and still further preferably 2 to 15 wt % relative to the active material particles included in the positive electrode material mixture.
The positive electrode core material (positive electrode current collector) may be any electron conductor, as long as it is chemically stable in the battery. For example, a foil or a sheet of aluminum, stainless steel, nickel, titanium, carbon, and conductive resin may be used. Particularly, aluminum foil and aluminum alloy foil are preferable. On the surface of the foil or the sheet, a layer of carbon or titanium may be added, and an oxide layer may be formed. Also, on the surface of the foil or sheet, unevenness may be added. For example, net, punched sheet, lath, porous material, formed material, fibrous molded material may be used. The thickness of the positive electrode core material is not particularly limited, but for example within a range of 1 to 500 μm.
In the following, elements other than the positive electrode are described. However, a lithium ion secondary battery of the present invention is characterized in that the positive electrode such as the above is included. Thus, elements other than the positive electrode are not particularly limited. The following is not to limit the present invention.
For the negative electrode capable of charging and discharging, for example, may be used is a negative electrode material mixture including a negative electrode active material and a binder, and including a conductive material and a thickener as arbitrary components being carried on a negative electrode core material. Such a negative electrode may be made by a method similar to that for the positive electrode.
The negative electrode active material may be a material capable of charging and discharging lithium electrochemically. For example, graphites, non-graphitizable carbon material, and lithium alloy may be used. The lithium alloy is preferably an alloy including particularly at least one selected from the group consisting of silicon, tin, aluminum, zinc, and magnesium. The average particle size of the negative electrode active material is not particularly limited, but preferably 1 to 30 μm.
The binder to be included in the negative electrode material mixture is not particularly limited, but for example, may be selected arbitrary from the materials shown as examples of the binder to be included in the positive electrode material mixture.
The conductive material to be included in the negative electrode material mixture may be any electron conductive material, as long as it is chemically stable in the battery. For example, graphites such as natural graphite (such as flake graphite) and artificial graphite; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as copper and nickel; and organic conductive material such as polyphenylene derivative may be used. These may be used singly, or may be used in combination of two or more. The amount of the conductive material to be added is not particularly limited, but preferably 1 to 30 wt %, and further preferably 1 to 10 wt % relative to the active material particles included in the negative electrode material mixture.
The negative electrode core material (negative electrode current collector) may be any electron conductor, as long as it is chemically stable in the battery. For example, a foil or sheet of stainless steel, nickel, copper, titanium, carbon, or conductive resin may be used. Copper foil or copper alloy foil is particularly preferable. On the surface of the foil or sheet, a layer of carbon, titanium, or nickel may be added, and an oxide layer may be formed. Also, on the surface of the foil or sheet, unevenness may be added. For example, net, punched sheet, lath, porous material, formed material, and fibrous molded material may be used. The thickness of the negative electrode core material is not particularly limited, but for example within a range of 1 to 500 μm.
For the non-aqueous electrolyte, a non-aqueous solvent dissolving a lithium salt therein is preferably used.
May be used for the non-aqueous solvent are, for example, cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinylene carbonate (VC); chain carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), and dipropyl carbonate (DPC); aliphatic carboxylic acid esters such as methyl formate, methyl acetate, methyl propionate, and ethyl propionate; lactones such as γ-butyrolactone and γ-valerolactone; chain ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), and ethoxymethoxyethane (EME); cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran; dimethylsulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propylnitrile, nitromethane, ethylmonoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ethylether, 1,3-propanesultone, anisole, dimethylsulfoxide, and N-methyl-2-pyrrolidone. These may be used singly, but preferably used in combination of two or more. Particularly, a solvent mixture of cyclic carbonate and chain carbonate; or a solvent mixture of cyclic carbonate, chain carbonate, and aliphatic carboxylic acid ester is preferable.
The lithium salt to be dissolved in the non-aqueous solvent includes, for example, LiClO4, LiBF4, LiPF6, LiAlCl4, LiSbF6, LiSCN, LiCl, LiCF3SO3, LiCF3CO2, Li(CF3SO2)2, LiAsF6, LiN(CF3SO2)2, LiB10Cl10, lithium lower aliphatic carboxylate, LiCl, LiBr, LiI, LiBCl4, lithium tetraphenylborate, and lithium imide salt. These may be used singly, or may be used in combination of two or more. However, at least LiPF6 is used preferably.
The amount of lithium salt to be dissolved relative to the non-aqueous solvent is not particularly limited, but the lithium salt concentration is preferably 0.2 to 2 mol/L, and further preferably 0.5 to 1.5 mol/L.
Various additives may be added to the non-aqueous electrolyte for improving battery's charge and discharge performance. The additives include, for example, triethylphosphite, triethanol amine, cyclic ether, ethylenediamine, n-glyme, pyridine, hexaphosphoric triamide, nitrobenzene derivative, crown ether, quaternary ammonium salt, and ethylene glycol dialkylether.
A separator has to be interposed between the positive electrode and the negative electrode.
For the separator, a microporous thin film having a high ion permeability, a predetermined mechanical strength, and insulating ability is preferably used. The microporous thin film preferably has a function of closing the pores at a certain temperature or more, to increase the battery resistance. The material used for the microporous thin film preferably includes polyolefin (polypropylene and polyethylene) that is excellent in resistance to organic solvents and is hydrophobic. A sheet made of glass fiber, nonwoven fabric, and woven fabric are also used as the separator. The pore size of the separator is, for example, 0.01 to 1 μm. The thickness of the separator is generally 10 to 300 μm. The porosity of the separator is generally 30 to 80%.
A polymer electrolyte including a non-aqueous electrolyte and a polymer material retaining the electrolyte may be used instead of the separator. The polymer electrolyte may be integrated with the positive electrode or the negative electrode. The polymer material retaining the non-aqueous electrolyte is not particularly limited, but preferably, for example, a copolymer of vinylidene fluoride and hexafluoropropylene is preferable.
The present invention is described in detail based on Examples in the following, but the present invention is not limited to Examples below.
EXAMPLE 1
Example Battery A1
(i) Synthesis of First Lithium-nickel Composite Oxide
Nickel sulfate, cobalt sulfate, and aluminum sulfate were mixed so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 80:15:5. The obtained mixture in an amount of 3.2 kg was dissolved in 10 L of water, to obtain a raw material solution. To the raw material solution, 400 g of sodium hydroxide was added to form a precipitate. The precipitate was sufficiently washed with water and dried, to obtain a coprecipitated hydroxide.
To 3 kg of the obtained coprecipitated hydroxide of Ni—Co—Al, 784 g of lithium hydroxide was mixed in, and the mixture was baked for 10 hours at a temperature of 750° C. under an atmosphere with an oxygen partial pressure of 0.5 atm, to obtain a first lithium-nickel composite oxide (LiNi0.8Co0.15Al0.05O2) including Al as element Me.
Various first lithium-nickel composite oxides were also synthesized by using various raw materials, instead of the above coprecipitated hydroxide of Ni—Co—Al. Evaluations were carried out for these as well, but the explanations are omitted in Examples below, since the obtained results were similar to the case of LiNi0.8Co0.15Al0.05O2.
(ii) Synthesis of Active Material Particles
<a> First Step
Tantalum pentaethoxide was dissolved in 10 L of ethanol. To the obtained solution, 2 kg of the synthesized first lithium-nickel composite oxide was dispersed. The amount of tantalum pentaethoxide dissolved in ethanol was set to 0.5 mol % relative to the first lithium-nickel composite oxide. The mixed solution of the first lithium-nickel composite oxide and the ethanol solution was stirred for 3 hours at 60° C. Afterwards, the mixed solution was filtrated and the residue thereof was dried for 2 hours at 100° C. As a result, a first lithium-nickel composite oxide carrying tantalum (Ta) as element M on the surface thereof was obtained.
<b> Second Step
The first lithium-nickel composite oxide (powder after drying) carrying tantalum on the surface thereof was allowed to stand under an environment with a temperature of 25° C. and a humidity of 55% for 24 hours. During this time, moisture in the atmosphere acted on the side reaction active points of the first lithium-nickel composite oxide surface to form NiOOH on the first lithium-nickel composite oxide surface. The formation of NiOOH was checked by XRD measurement and ESCA measurement.
<c> Third Step
The first lithium-nickel composite oxide with NiOOH formed on the surface thereof was baked preliminary for 6 hours at 300° C. under a dry air atmosphere (humidity 19%, pressure 101 KPa). Afterwards, a main baking was carried out for 6 hours at 650° C. under an atmosphere of 100% oxygen (pressure 101 KPa), and lastly, an annealing was carried out for 4 hours at 400° C. under an atmosphere of 100% oxygen (pressure 101 KPa). By this baking, NiOOH on the first lithium-nickel composite oxide surface is converted to Ni1-δO (0≦δ) having the NaCl-type crystal structure. Thus, active material particles having a surface layer portion including Ta and Ni1-δO (0≦δ) was obtained. The presence of Ni1-δO (0≦δ) having the NaCl-type crystal structure was confirmed by XRD measurement or XENES measurement. In Examples below as well, presence of Ni1-δO (0≦δ) in the active material particles was confirmed by XRD measurement or XENES measurement.
(iii) Positive Electrode Preparation
The obtained active material particles in an amount of 1 kg was stirred with a double-armed kneader along with 0.5 kg of PVDF#1320 (an N-methyl-2-pyrrolidone (NMP) solution including 12 wt % of PVDF) manufactured by Kureha Corporation, 40 g of acetylene black, and an appropriate amount of NMP, to prepare a positive electrode material mixture paste. This paste was applied on both sides of aluminum foil with a thickness of 20 μm, dried, and rolled to give a total thickness of 160 μm. Afterwards, the obtained electrode plate was cut to give a width that can be inserted to a battery case of cylindrical type 18650, to obtain a positive electrode.
(iv) Negative Electrode Preparation
A negative electrode material mixture paste was prepared by stirring 3 kg of artificial graphite, 200 g of BM-400B (dispersion including 40 wt % of modified styrene-butadiene rubber) manufactured by Zeon Corporation, 50 g of carboxymethylcellulose (CMC), and an appropriate amount of water with a double-armed kneader. This paste was applied on both sides of copper foil with a thickness of 12 μm, dried, and rolled to give a total thickness of 160 μm. Afterwards, the obtained electrode plate was cut to give a width that can be inserted to the above battery case, to obtain a negative electrode.
(v) Battery Assembly
Description is given by referring to FIG. 2. First, a positive electrode 21 and a negative electrode 22 were wound with a separator 23 interposed therebetween, to form an electrode assembly. For the separator 23, a composite film (2300 manufactured by Celgard KK, thickness of 25 μm) comprising polyethylene and polypropylene was used.
To the positive electrode 21 and the negative electrode 22, a positive electrode lead 24 and a negative electrode lead 25 of nickel were attached, respectively. An upper insulating plate 26 and a lower insulating plate 27 were placed on the top face and the bottom face of the electrode assembly, respectively, and inserted into a battery case 28, and further, 5 g of a non-aqueous electrolyte was injected into the battery case 28.
For the non-aqueous electrolyte, to a solvent mixture of ethylene carbonate and methylethyl carbonate with a volume ratio of 10:30, LiPF6 was dissolved with a concentration of 1.5 mol/L and used.
Afterwards, a positive electrode terminal 30 of a sealing plate 29 for sealing the opening of the battery case 28, and the positive electrode lead 24 were brought into conduction, and the opening was sealed. A cylindrical type 18650 lithium secondary battery was thus completed. This battery was named as Example Battery A1.
Example Battery A2
Battery A2 was made in the same manner as Battery A1 except that the amount of tantalum pentaethoxide dissolved in 10 L of ethanol was changed to 2.0 mol % relative to the first lithium-nickel composite oxide.
Example Battery A3
Battery A3 was made in the same manner as Battery A1, except that in the first step of synthesizing active material particles, a solution dissolving aluminum (Al: element M) triisopropoxide in 10 L of isopropanol was used instead of the ethanol solution of tantalum pentaethoxide. The amount of aluminum triisopropoxide dissolved was set to 0.5 mol % relative to the first lithium-nickel composite oxide.
Example Battery A4
Battery A4 was made in the same manner as Battery A3, except that the amount of aluminum triisopropoxide dissolved in 10 L of isopropanol was changed to 2.0 mol % relative to the first lithium-nickel composite oxide.
Example Battery A5
Battery A5 was made in the same manner as Battery A1, except that in the first step of synthesizing active material particles, a solution dissolving zirconium (Zr: element M) tetra-n-butoxide in 10 L of butanol was used instead of the ethanol solution of tantalum pentaethoxide. The amount of zirconium tetra-n-butoxide dissolved was set to 0.5 mol % relative to the first lithium-nickel composite oxide.
Example Battery A6
Battery A6 was made in the same manner as Battery A5, except that the amount of zirconium tetra-n-butoxide dissolved in 10 L of butanol was changed to 2.0 mol % relative to the first lithium-nickel composite oxide.
Example Battery A7
Battery A7 was made in the same manner as Battery A1, except that in the first step of synthesizing active material particles, a solution dissolving magnesium acetate (Mg: element M) in 10 L of ethanol was used instead of the ethanol solution of tantalum pentaethoxide. The amount of magnesium acetate was set to 0.5 mol % relative to the first lithium-nickel composite oxide.
Example Battery A8
Battery A8 was made in the same manner as Battery A7, except that amount of magnesium acetate dissolved in 10 L of ethanol was changed to 2.0 mol % relative to the first lithium-nickel composite oxide.
Example Battery A9
Battery A9 was made in the same manner as Battery A1, except that in the first step of synthesizing active material particles, a solution dissolving indium nitrate (In: element M) in 10 L of ethanol was used instead of the ethanol solution of tantalum pentaethoxide. The amount of indium nitrate dissolved was set to 0.5 mol % relative to the first lithium-nickel composite oxide.
Example Battery A10
Battery A10 was made in the same manner as Battery A9, except that the amount of indium nitrate dissolved in 10 L of ethanol was changed to 2.0 mol % relative to the first lithium-nickel composite oxide.
Example Battery A11
In the first step of synthesizing active material particles, 2 kg of the first lithium-nickel composite oxide was dispersed in 10 L of an aqueous solution of sodium hydroxide with pH13 instead of the ethanol solution of tantalum pentaethoxide. Tin sulfate (Sn: element M) in an amount of 0.5 mol % relative to the first lithium-nickel composite oxide was dissolved in 100 g of distilled water. To a mixed solution of the first lithium-nickel composite oxide and the aqueous solution of sodium hydroxide, an aqueous solution of tin sulfate was dropped for 10 minutes. Afterwards, Battery A11 was made in the same manner as Battery A1, except that the stirring was carried out for 3 hours at 100° C.
Example Battery A12
Battery A12 was made in the same manner as Battery A11, except that the amount of tin sulfate dissolved in 100 g of distilled water was changed to 2.0 mol % relative to the first lithium-nickel composite oxide.
Example Battery A13
Battery A13 was made in the same manner as Battery A11, except that tin sulfate was changed to manganese sulfate (Mn: element M).
Example Battery A14
Battery A14 was made in the same manner as Battery A12, except that tin sulfate was changed to manganese sulfate.
Example Battery A15
Battery A15 was made in the same manner as Battery A11, except that tin sulfate was changed to boric acid (B: element M).
Example Battery A16
Battery A16 was made in the same manner as Battery A12, except that tin sulfate was changed to boric acid.
Example Battery A17
Battery A17 was made in the same manner as Battery A11, except that tin sulfate was changed to sodium tungstate (W: element M).
Example Battery A18
Battery A18 was made in the same manner as Battery A12, except that tin sulfate was changed to sodium tungstate.
Example Battery A19
Battery A19 was made in the same manner as Battery A11, except that tin sulfate was changed to niobium pentachloride (Nb: element M).
Example Battery A20
Battery A20 was made in the same manner as Battery A12, except that tin sulfate was changed to niobium pentachloride.
Example Battery A21
Battery A21 was made in the same manner as Battery A11, except that tin sulfate was changed to ammonium heptamolybdate (Mo: element M).
Example Battery A22
Battery A22 was made in the same manner as Battery A12, except that tin sulfate was changed to ammonium heptamolybdate.
Example Batteries A23 to A33
Batteries A23 to A33 were made in the same manner as Batteries 1A, 3A, 5A, 7A, 9A, 11A, 13A, 15A, 17A, 19A, and 21A, except that the respective amount of tantalum pentaethoxide, aluminum triisopropoxide, zirconium tetra-n-butoxide, magnesium acetate, indium nitrate, tin sulfate, manganese sulfate, boric acid, sodium tungstate, niobium pentachloride, and ammonium heptamolybdate was set to 2.5 mol % relative to the first lithium-nickel composite oxide.
Example Batteries A34 to A44
Batteries A34 to A44 were made in the same manner as Batteries 1A, 3A, 5A, 7A, 9A, 11A, 13A, 15A, 17A, 19A, and 21A, except that in the second step of synthesizing the active material particles, the environment for allowing the first lithium-nickel composite oxide carrying element M (powder after drying) to stand was changed to an environment with a temperature of 60° C. and a humidity of 55%.
Comparative Example Batteries a1 to a11
Batteries a1 to a11 were made in the same manner as Batteries 1A, 3A, 5A, 7A, 9A, 11A, 13A, 15A, 17A, 19A, and 21A, respectively, except that in the second step of synthesizing the active material particles, the environment for allowing the first lithium-nickel composite oxide carrying element M (powder after drying) to stand was changed to an environment with a temperature of 25° C. and a humidity of 20%.
No Ni1-δO (0≦δ) production was confirmed in XRD measurement on active material particles in each battery.
Comparative Example Batteries a12 to a22
Batteries a12 to a22 were made in the same manner as Batteries 1A, 3A, 5A, 7A, 9A, 11A, 13A, 15A, 17A, 19A, and 21A, except that in the third step of synthesizing the active material particles, the atmosphere of preliminarily baking the first lithium-nickel composite oxide with NiOOH formed on the surface thereof was changed from the dry air atmosphere to an atmosphere of 100% oxygen (pressure 101 KPa).
No Ni1-δO production was confirmed in XRD measurement on the active material particles of each battery. Preliminarily baking in highly oxidizing atmosphere probably causes Ni1-δO (0≦δ), i.e., a reduction product, not to be produced.
Comparative Example Batteries a23 to a33
Batteries a23 to a33 were made in the same manner as Batteries 1A, 3A, 5A, 7A, 9A, 11A, 13A, 15A, 17A, 19A, and 21A, except that in the third step of synthesizing the active material particles, the atmospheres of the main baking and of the following annealing of the first lithium-nickel composite oxide with NiOOH formed on the surface thereof were changed from the atmosphere of 100% oxygen to a dry air atmosphere (humidity 19%, pressure 101 KPa).
No Ni1-δO (0≦δ) production was confirmed in XRD measurement on the active material particles of each battery. The main baking in a dry air atmosphere probably causes no Ni1-δO (0≦δ) production, but causes the active material itself to be changed into a different phase.
Comparative Example Battery a34
Battery a34 was made in the same manner as Battery A1, except that in the synthesizing of the active material particles, the first step was not carried out, and the first lithium-nickel composite oxide was allowed to stand as is in the second step for 24 hours, under an environment with a temperature of 25° C. and a humidity of 55%.
NiO production was confirmed in an analysis on the active material particles.
Comparative Example Battery a35
Battery a35 was made in the same manner as Battery A1, except that the first lithium-nickel composite oxide to which 0.5 mol % of NiO powder was added was used as the positive electrode active material.
Comparative Example Battery a36
A first lithium-nickel composite oxide was heat-treated under an atmosphere of a mixed gas of a 95:5 molar ratio nitrogen and hydrogen at 400° C. for 6 hours, to form a reduced layer including Ni and Co having a low valence on the surface of the first lithium-nickel composite oxide. Battery a36 was made in the same manner as Battery A1, except that a first lithium-nickel composite oxide with the thus obtained reduced layer was used as the positive electrode active material.
Comparative Example Battery a37
Battery a37 was made in the same manner as Battery A1, except that a first lithium-nickel composite oxide not containing element M and Ni1-δO (0≦δ) was used as is as the positive electrode active material.
[Evaluation 1]
Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37 were evaluated with the method below. The results are shown in Tables 1A and 1B.







TABLE 1A







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.05O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Ex.
A1
Ta
0.5
25 · 55
Dry Air
Oxygen
1980
1900
70


Ex.
A2

2.0



1985
1900
75


Ex.
A3
Al
0.5



1985
1905
70


Ex.
A4

2.0



1990
1905
71


Ex.
A5
Zr
0.5



1990
1910
65


Ex.
A6

2.0



1990
1910
65


Ex.
A7
Mg
0.5



1995
1915
70


Ex.
A8

2.0



1992
1920
72


Ex.
A9
In
0.5



1990
1925
71


Ex.
A10

2.0



1995
1920
65


Ex.
A11
Sn
0.5



1990
1910
72


Ex.
A12

2.0



1989
1905
71


Ex.
A13
Mn
0.5



1990
1900
65


Ex.
A14

2.0



1991
1900
70


Ex.
A15
B
0.5



1991
1900
72


Ex.
A16

2.0



1990
1905
75


Ex.
A17
W
0.5



1990
1902
74


Ex.
A18

2.0



1992
1910
72


Ex.
A19
Nb
0.5



1980
1905
70


Ex.
A20

2.0



1990
1905
71


Ex.
A21
Mo
0.5



1990
1905
65


Ex.
A22

2.0



1990
1900
70


Ex.
A23
Ta
2.5



1990
1800
70


Ex.
A24
Al




1992
1810
70


Ex.
A25
Zr




1980
1800
70


Ex.
A26
Mg




1985
1805
75


Ex.
A27
In




1982
1800
78


Ex.
A28
Sn




1990
1805
68


Ex.
A29
Mn




1990
1802
70


Ex.
A30
B




1989
1800
71


Ex.
A31
W




1990
1810
69


Ex.
A32
Nb




1990
1900
70


Ex.
A33
Mo




1992
1900
72


Ex.
A34
Ta
0.5
60 · 55


1800
1701
70


Ex.
A35
Al




1805
1700
68


Ex.
A36
Zr




1810
1710
69


Ex.
A37
Mg




1820
1715
71


Ex.
A38
In




1800
1700
71


Ex.
A39
Sn




1805
1700
72


Ex.
A40
Mn




1807
1702
68


Ex.
A41
B




1800
1710
67


Ex.
A42
W




1800
1705
70


Ex.
A43
Nb




1800
1700
70


Ex.
A44
Mo




1805
1700
68
















TABLE 1B







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.05O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
a1
Ta
0.5
25 · 20
Dry Air
Oxygen
1990
1920
120


Comp. Ex.
a2
Al




1990
1900
115


Comp. Ex.
a3
Zr




1989
1900
120


Comp. Ex.
a4
Mg




1990
1899
110


Comp. Ex.
a5
In




1987
1890
110


Comp. Ex.
a6
Sn




1985
1900
120


Comp. Ex.
a7
Mn




1988
1905
115


Comp. Ex.
a8
B




1990
1900
120


Comp. Ex.
a9
W




1985
1900
125


Comp. Ex.
a10
Nb




1992
1902
110


Comp. Ex.
a11
Mo




1990
1900
122


Comp. Ex.
a12
Ta

25 · 55
Oxygen

1982
1910
117


Comp. Ex.
a13
Al




1980
1910
122


Comp. Ex.
a14
Zr




1985
1915
125


Comp. Ex.
a15
Mg




1990
1915
120


Comp. Ex.
a16
In




1995
1910
118


Comp. Ex.
a17
Sn




1995
1900
115


Comp. Ex.
a18
Mn




1990
1905
112


Comp. Ex.
a19
B




1990
1910
110


Comp. Ex.
a20
W




1992
1908
115


Comp. Ex.
a21
Nb




1990
1905
110


Comp. Ex.
a22
Mo




1989
1900
120


Comp. Ex.
a23
Ta


Dry Air
Dry Air
1990
1910
120


Comp. Ex.
a24
Al




1985
1905
109


Comp. Ex.
a25
Zr




1988
1905
105


Comp. Ex.
a26
Mg




1986
1900
100


Comp. Ex.
a27
In




1990
1915
102


Comp. Ex.
a28
Sn




1970
1900
100


Comp. Ex.
a29
Mn




1985
1905
106


Comp. Ex.
a30
B




1985
1900
107


Comp. Ex.
a31
W




1990
1910
100


Comp. Ex.
a32
Nb




1991
1904
100


Comp. Ex.
a33
Mo




1990
1905
105


Comp. Ex.
a34
Not
—
25 · 55

Oxygen
1800
1700
75




Added





















Comp. Ex.
a35
Not
0.5
Not Carried Out
1995
1910
110


Comp. Ex.
a36
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
1990
1910
115






(molar ratio) treatment at 400° C.









for 6 hours





Comp. Ex.
a37


Not Carried Out
1995
1915
140









(Discharge Performance)

Each battery was preliminary charged and discharged twice, and then stored under an environment of 40° C. for 2 days. Afterwards, the following two patterns of charging and discharging were carried out for each battery. The battery designed capacity was 2000 mAh.
First Pattern
(1) Constant Current Charging (20° C.): 1400 mA (End Voltage 4.2 V)
(2) Constant Voltage Charging (20° C.): 4.2 V (End Current 100 mA)
(3) Constant Current Discharging (0° C.): 400 mA (End Voltage 3 V)
Second Pattern
(1) Constant Current Charging (20° C.): 1400 mA (end voltage 4.2 V)
(2) Constant Voltage Charging (20° C.): 4.2 V (end current 100 mA)
(3) Constant Current Discharging (0° C.): 4000 mA (end voltage 3 V)
The discharge capacities obtained in the first and the second pattern are shown in Tables 1A and 1B.
(Safety)
A battery crush test was carried out under an environment of 60° C. for evaluating safety upon internal short-circuit occurrence. First, the following charging was carried out for those batteries after the discharge performance evaluation under an environment of 20° C. The battery designed capacity was 2000 mAh.
(1) Constant Current Charging: 1400 mA (end voltage 4.25 V)
(2) Constant Voltage Charging: 4.25 V (end current 100 mA)
An iron rod with a 10 mm diameter was thrust at a speed of 5 mm/sec from a side face of the charged battery under an environment of 60° C. to break the battery. The temperatures reached at the broken portion of the battery after 90 seconds are shown in Tables 1A and 1B.
The evaluation results are shown below.
In Example Batteries A1 to A22, in which the active material particle surface layer portion includes element M and Ni1-δO (0≦δ≦0.1), and the amount of element M is 0.5 mol % or 2 mol % relative to the first lithium-nickel composite oxide, the degree of the heat generation was quite small in the crush test. The discharge capacity of these batteries at 0° C. in 2 CmA (4000 mAh) discharging was the same level as that of Comparative Example Battery a37 using the first lithium-nickel composite oxide as is.
In Example Batteries A23 to A33, in which the amount of element M relative to the lithium composite oxide is 2.5 mol %, the discharge capacity in 2 CmA (4000 mAh) discharging at 0° C. declined. The compound of element M included in the surface layer portion of the first lithium-nickel composite oxide was electrochemically inactive and thus probably became resistance.
Example Batteries A34 to A44, in which a condition for allowing the first lithium-nickel composite oxide carrying element M before baking to stand was changed to give high temperature, the discharge capacity tended to be low. This is probably because the portions other than the side reaction active points of the first lithium-nickel composite oxide were changed to Ni1-δO.
In Comparative Example Battery a34, in which the first lithium-nickel composite oxide was baked after being allowed to stand under an environment of a temperature of 25° C. and a humidity of 55% for 24 hours and used without carrying element M, the discharge capacity was not sufficient. This is probably because the absence of element M at the surface caused the first lithium-nickel composite oxide to deteriorate.
In Comparative Example Batteries a1 to a11, in which a condition for the first lithium-nickel composite oxide carrying element M before baking to stand was changed to give low humidity, and Comparative Example Batteries a12 to a33, in which the baking atmosphere was changed, a great amount of heat was generated in the crush test. This is probably because Ni1-δO (0≦δ), which inactivates the side reaction active points of the first lithium-nickel composite oxide was not produced.
In Comparative Example Battery a35 as well, in which the first lithium-nickel composite oxide with NiO added was used for the positive electrode active material, since the side reaction active points did not disappear, a great amount of heat generated in the crush test.
In Comparative Example Battery a36, in which the lithium composite oxide surface with the reduced layer formed on the surface thereof was used as the positive electrode active material, the discharge capacity with 2 CmA (4000 mAh) at 0° C. was insufficient. This is probably because the first lithium-nickel composite oxide surface was covered with Ni or Co having a low oxidation number and low electrochemical activity.
EXAMPLE 2
A first lithium-nickel composite oxide having a composition of LiNi0.9Co0.07Al0.03O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 90:7:3 upon synthesizing the first lithium-nickel composite oxide. Example Batteries B1 to B44 and Comparative Example Batteries b1 to b37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 2A and 2B.







TABLE 2A







First Lithium-Nickel Composite Oxide: LiNi0.90Co0.07Al0.03O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Ex.
B1
Ta
0.5
25 · 55
Dry Air
Oxygen
1485
1460
65


Ex.
B2

2.0



1490
1455
65


Ex.
B3
Al
0.5



1480
1462
70


Ex.
B4

2.0



1475
1460
65


Ex.
B5
Zr
0.5



1470
1460
70


Ex.
B6

2.0



1475
1458
71


Ex.
B7
Mg
0.5



1470
1455
65


Ex.
B8

2.0



1470
1460
65


Ex.
B9
In
0.5



1480
1455
71


Ex.
B10

2.0



1485
1457
65


Ex.
B11
Sn
0.5



1480
1456
65


Ex.
B12

2.0



1480
1450
65


Ex.
B13
Mn
0.5



1482
1460
71


Ex.
B14

2.0



1485
1462
72


Ex.
B15
B
0.5



1490
1465
72


Ex.
B16

2.0



1475
1455
74


Ex.
B17
W
0.5



1475
1455
72


Ex.
B18

2.0



1480
1460
75


Ex.
B19
Nb
0.5



1480
1460
70


Ex.
B20

2.0



1482
1460
72


Ex.
B21
Mo
0.5



1490
1465
72


Ex.
B22

2.0



1485
1460
70


Ex.
B23
Ta
2.5



1480
1330
70


Ex.
B24
Al




1490
1330
70


Ex.
B25
Zr




1485
1335
70


Ex.
B26
Mg




1486
1332
75


Ex.
B27
In




1490
1332
70


Ex.
B28
Sn




1488
1335
70


Ex.
B29
Mn




1480
1335
70


Ex.
B30
B




1485
1330
75


Ex.
B31
W




1490
1330
69


Ex.
B32
Nb




1485
1325
71


Ex.
B33
Mo




1490
1330
72


Ex.
B34
Ta
0.5
60 · 55


1300
1200
75


Ex.
B35
Al




1305
1205
72


Ex.
B36
Zr




1302
1200
75


Ex.
B37
Mg




1300
1200
74


Ex.
B38
In




1305
1205
72


Ex.
B39
Sn




1302
1207
75


Ex.
B40
Mn




1300
1202
74


Ex.
B41
B




1300
1205
70


Ex.
B42
W




1305
1205
71


Ex.
B43
Nb




1300
1200
72


Ex.
B44
Mo




1302
1205
71
















TABLE 2B







First Lithium-Nickel Composite Oxide: LiNi0.90Co0.07Al0.03O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
b1
Ta
0.5
25 · 20
Dry Air
Oxygen
1490
1455
120


Comp. Ex.
b2
Al




1492
1456
106


Comp. Ex.
b3
Zr




1495
1457
107


Comp. Ex.
b4
Mg




1487
1455
100


Comp. Ex.
b5
In




1488
1450
117


Comp. Ex.
b6
Sn




1489
1460
115


Comp. Ex.
b7
Mn




1490
1465
120


Comp. Ex.
b8
B




1492
1466
118


Comp. Ex.
b9
W




1496
1455
115


Comp. Ex.
b10
Nb




1492
1460
120


Comp. Ex.
b11
Mo




1495
1450
120


Comp. Ex.
b12
Ta

25 · 55
Oxygen

1495
1450
112


Comp. Ex.
b13
Al




1497
1460
106


Comp. Ex.
b14
Zr




1490
1460
115


Comp. Ex.
b15
Mg




1485
1450
120


Comp. Ex.
b16
In




1489
1450
118


Comp. Ex.
b17
Sn




1480
1455
115


Comp. Ex.
b18
Mn




1485
1452
112


Comp. Ex.
b19
B




1480
1456
110


Comp. Ex.
b20
W




1490
1462
115


Comp. Ex.
b21
Nb




1492
1460
112


Comp. Ex.
b22
Mo




1495
1462
110


Comp. Ex.
b23
Ta


Dry Air
Dry Air
1490
1462
120


Comp. Ex.
b24
Al




1490
1465
109


Comp. Ex.
b25
Zr




1485
1466
105


Comp. Ex.
b26
Mg




1488
1468
100


Comp. Ex.
b27
In




1488
1468
102


Comp. Ex.
b28
Sn




1487
1450
100


Comp. Ex.
b29
Mn




1485
1450
106


Comp. Ex.
b30
B




1485
1450
107


Comp. Ex.
b31
W




1490
1450
100


Comp. Ex.
b32
Nb




1488
1445
105


Comp. Ex.
b33
Mo




1480
1450
105


Comp. Ex.
b34
Not
—
25 · 55

Oxygen
1305
1202
76




Added





















Comp. Ex.
b35
Not
0.5
Not Carried Out
1490
1460
110


Comp. Ex.
b36
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
1490
1460
115






(molar ratio)









treatment at 400° C. for 6 hours





Comp. Ex.
b37


Not Carried Out
1495
1465
130









EXAMPLE 3
A first lithium-nickel composite oxide having a composition of LiNi0.25Co0.25Al0.50O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate, so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 25:25:50 upon synthesizing the first lithium-nickel composite oxide. Example Batteries C1 to C44 and Comparative Example Batteries c1 to c37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 3A and 3B.







TABLE 3A







First Lithium-Nickel Composite Oxide: LiNi0.25Co0.25Al0.50O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Ex.
C1
Ta
0.5
25 · 55
Dry Air
Oxygen
1485
1460
68


Ex.
C2

2.0



1490
1455
64


Ex.
C3
Al
0.5



1480
1462
62


Ex.
C4

2.0



1475
1460
70


Ex.
C5
Zr
0.5



1470
1460
70


Ex.
C6

2.0



1475
1458
70


Ex.
C7
Mg
0.5



1470
1455
75


Ex.
C8

2.0



1470
1460
72


Ex.
C9
In
0.5



1480
1455
66


Ex.
C10

2.0



1485
1457
68


Ex.
C11
Sn
0.5



1480
1456
64


Ex.
C12

2.0



1480
1450
62


Ex.
C13
Mn
0.5



1482
1460
65


Ex.
C14

2.0



1485
1462
59


Ex.
C15
B
0.5



1490
1465
60


Ex.
C16

2.0



1475
1455
61


Ex.
C17
W
0.5



1475
1455
65


Ex.
C18

2.0



1480
1460
67


Ex.
C19
Nb
0.5



1480
1455
66


Ex.
C20

2.0



1485
1457
68


Ex.
C21
Mo
0.5



1480
1456
64


Ex.
C22

2.0



1480
1450
62


Ex.
C23
Ta
2.5



1480
1350
68


Ex.
C24
Al




1490
1355
64


Ex.
C25
Zr




1485
1350
65


Ex.
C26
Mg




1486
1350
66


Ex.
C27
In




1490
1352
69


Ex.
C28
Sn




1488
1357
70


Ex.
C29
Mn




1480
1356
70


Ex.
C30
B




1485
1350
75


Ex.
C31
W




1490
1350
69


Ex.
C32
Nb




1490
1352
69


Ex.
C33
Mo




1488
1357
70


Ex.
C34
Ta
0.5
60 · 55


1350
1200
70


Ex.
C35
Al




1355
1200
71


Ex.
C36
Zr




1350
1205
72


Ex.
C37
Mg




1350
1205
68


Ex.
C38
In




1352
1200
69


Ex.
C39
Sn




1355
1202
67


Ex.
C40
Mn




1355
1205
70


Ex.
C41
B




1345
1200
70


Ex.
C42
W




1345
1200
75


Ex.
C43
Nb




1350
1205
68


Ex.
C44
Mo




1352
1200
69
















TABLE 3B







First Lithium-Nickel Composite Oxide: LiNi0.25Co0.25Al0.50O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
c1
Ta
0.5
25 · 20
Dry Air
Oxygen
1490
1450
110


Comp. Ex.
c2
Al




1492
1456
105


Comp. Ex.
c3
Zr




1495
1457
107


Comp. Ex.
c4
Mg




1487
1455
109


Comp. Ex.
c5
In




1488
1450
110


Comp. Ex.
c6
Sn




1489
1460
105


Comp. Ex.
c7
Mn




1490
1465
108


Comp. Ex.
c8
B




1492
1466
110


Comp. Ex.
c9
W




1496
1455
115


Comp. Ex.
c10
Nb




1488
1450
110


Comp. Ex.
c11
Mo




1489
1460
105


Comp. Ex.
c12
Ta

25 · 55
Oxygen

1495
1450
112


Comp. Ex.
c13
Al




1497
1460
110


Comp. Ex.
c14
Zr




1490
1460
110


Comp. Ex.
c15
Mg




1485
1450
115


Comp. Ex.
c16
In




1489
1450
120


Comp. Ex.
c17
Sn




1480
1455
120


Comp. Ex.
c18
Mn




1485
1452
118


Comp. Ex.
c19
B




1480
1456
116


Comp. Ex.
c20
W




1490
1462
119


Comp. Ex.
c21
Nb




1480
1455
120


Comp. Ex.
c22
Mo




1485
1452
118


Comp. Ex.
c23
Ta


Dry Air
Dry Air
1490
1462
120


Comp. Ex.
c24
Al




1490
1465
120


Comp. Ex.
c25
Zr




1485
1466
120


Comp. Ex.
c26
Mg




1488
1468
115


Comp. Ex.
c27
In




1488
1468
112


Comp. Ex.
c28
Sn




1487
1450
116


Comp. Ex.
c29
Mn




1485
1450
117


Comp. Ex.
c30
B




1485
1450
118


Comp. Ex.
c31
W




1490
1450
120


Comp. Ex.
c32
Nb




1487
1450
116


Comp. Ex.
c33
Mo




1485
1450
117


Comp. Ex.
c34
Not
—
25 · 55

Oxygen
1340
1180
77




Added





















Comp. Ex.
c35
Not
0.5
Not Carried Out
1490
1460
120


Comp. Ex.
c36
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
1490
1460
120






(molar ratio)









treated at 400° C. for 6 hours





Comp. Ex.
c37


Not Carried Out
1495
1465
130









EXAMPLE 4
A first lithium-nickel composite oxide having a composition of LiNi0.25Co0.50Al0.25O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate, so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 25:50:25 upon synthesizing the first lithium-nickel composite oxide. Example Batteries D1 to D44 and Comparative Example Batteries d1 to d37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 4A and 4B.







TABLE 4A







First Lithium-Nickel Composite Oxide: LiNi0.25Co0.50Al0.25O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Ex.
D1
Ta
0.5
25 · 55
Dry Air
Oxygen
1880
1810
60


Ex.
D2

2.0



1890
1815
65


Ex.
D3
Al
0.5



1885
1812
64


Ex.
D4

2.0



1884
1810
61


Ex.
D5
Zr
0.5



1882
1810
65


Ex.
D6

2.0



1880
1815
65


Ex.
D7
Mg
0.5



1892
1815
70


Ex.
D8

2.0



1892
1810
70


Ex.
D9
In
0.5



1880
1812
68


Ex.
D10

2.0



1880
1816
67


Ex.
D11
Sn
0.5



1880
1810
65


Ex.
D12

2.0



1889
1815
65


Ex.
D13
Mn
0.5



1889
1812
70


Ex.
D14

2.0



1887
1812
64


Ex.
D15
B
0.5



1888
1812
65


Ex.
D16

2.0



1888
1810
65


Ex.
D17
W
0.5



1888
1810
70


Ex.
D18

2.0



1888
1810
72


Ex.
D19
Nb
0.5



1880
1810
65


Ex.
D20

2.0



1889
1815
65


Ex.
D21
Mo
0.5



1889
1812
70


Ex.
D22

2.0



1887
1812
64


Ex.
D23
Ta
2.5



1889
1600
68


Ex.
D24
Al




1890
1610
65


Ex.
D25
Zr




1892
1605
65


Ex.
D26
Mg




1895
1605
62


Ex.
D27
In




1897
1601
62


Ex.
D28
Sn




1897
1605
72


Ex.
D29
Mn




1890
1610
70


Ex.
D30
B




1890
1610
70


Ex.
D31
W




1885
1600
70


Ex.
D32
Nb




1897
1601
62


Ex.
D33
Mo




1897
1605
72


Ex.
D34
Ta
0.5
60 · 55


1620
1500
68


Ex.
D35
Al




1620
1505
67


Ex.
D36
Zr




1625
1510
70


Ex.
D37
Mg




1630
1510
71


Ex.
D38
In




1635
1500
71


Ex.
D39
Sn




1620
1500
71


Ex.
D40
Mn




1625
1505
72


Ex.
D41
B




1620
1502
68


Ex.
D42
W




1625
1500
69


Ex.
D43
Nb




1620
1500
71


Ex.
D44
Mo




1625
1505
72
















TABLE 4B







First Lithium-Nickel Composite Oxide: LiNi0.25Co0.50Al0.25O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
d1
Ta
0.5
25 · 20
Dry Air
Oxygen
1880
1812
120


Comp. Ex.
d2
Al




1885
1812
115


Comp. Ex.
d3
Zr




1885
1815
111


Comp. Ex.
d4
Mg




1888
1815
120


Comp. Ex.
d5
In




1887
1815
112


Comp. Ex.
d6
Sn




1889
1812
115


Comp. Ex.
d7
Mn




1890
1810
118


Comp. Ex.
d8
B




1892
1810
118


Comp. Ex.
d9
W




1891
1810
120


Comp. Ex.
d10
Nb




1889
1812
115


Comp. Ex.
d11
Mo




1890
1810
118


Comp. Ex.
d12
Ta

25 · 55
Oxygen

1891
1815
110


Comp. Ex.
d13
Al




1890
1812
112


Comp. Ex.
d14
Zr




1890
1812
112


Comp. Ex.
d15
Mg




1890
1812
118


Comp. Ex.
d16
In




1890
1812
118


Comp. Ex.
d17
Sn




1890
1815
115


Comp. Ex.
d18
Mn




1890
1810
120


Comp. Ex.
d19
B




1888
1811
120


Comp. Ex.
d20
W




1887
1811
120


Comp. Ex.
d21
Nb




1890
1815
115


Comp. Ex.
d22
Mo




1890
1810
120


Comp. Ex.
d23
Ta


Dry Air
Dry Air
1885
1816
110


Comp. Ex.
d24
Al




1890
1817
110


Comp. Ex.
d25
Zr




1890
1818
105


Comp. Ex.
d26
Mg




1888
1818
108


Comp. Ex.
d27
In




1887
1817
107


Comp. Ex.
d28
Sn




1886
1817
109


Comp. Ex.
d29
Mn




1892
1818
110


Comp. Ex.
d30
B




1892
1817
110


Comp. Ex.
d31
W




1892
1818
112


Comp. Ex.
d32
Nb




1886
1817
109


Comp. Ex.
d33
Mo




1892
1818
110


Comp. Ex.
d34
Not
—
25 · 55

Oxygen
1615
1480
71




Added





















Comp. Ex.
d35
Not
0.5
Not Carried Out
1890
1818
112


Comp. Ex.
d36
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
1888
1818
115






(molar ratio)









treated at 400° C. for 6 hours





Comp. Ex.
d37


Not Carried Out
1892
1815
120









EXAMPLE 5
A first lithium-nickel composite oxide having a composition of LiNi0.90Co0.10O2 was obtained by using nickel sulfate and cobalt sulfate without using aluminum sulfate, so that a molar ratio of Ni atoms and Co atoms was 90:10 upon synthesizing the first lithium-nickel composite oxide. Example Batteries E1 to E44 and Comparative Example Batteries e1 to e37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 5A and 5B.







TABLE 5A







First Lithium-Nickel Composite Oxide: LiNi0.90Co0.10O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Ex.
E1
Ta
0.5
25 · 55
Dry Air
Oxygen
2000
1900
65


Ex.
E2

2.0



2005
1905
70


Ex.
E3
Al
0.5



2004
1902
68


Ex.
E4

2.0



2002
1900
62


Ex.
E5
Zr
0.5



2000
1902
62


Ex.
E6

2.0



2000
1900
64


Ex.
E7
Mg
0.5



1999
1900
65


Ex.
E8

2.0



1998
1905
70


Ex.
E9
In
0.5



2002
1900
71


Ex.
E10

2.0



2000
1900
75


Ex.
E11
Sn
0.5



2000
1905
64


Ex.
E12

2.0



2005
1904
68


Ex.
E13
Mn
0.5



2000
1902
62


Ex.
E14

2.0



2004
1902
65


Ex.
E15
B
0.5



2002
1900
62


Ex.
E16

2.0



1999
1910
67


Ex.
E17
W
0.5



2002
1910
70


Ex.
E18

2.0



2000
1915
72


Ex.
E19
Nb
0.5



2002
1900
71


Ex.
E20

2.0



2000
1900
75


Ex.
E21
Mo
0.5



2004
1902
65


Ex.
E22

2.0



2002
1900
62


Ex.
E23
Ta
2.5



2000
1700
69


Ex.
E24
Al




2002
1702
68


Ex.
E25
Zr




1999
1710
67


Ex.
E26
Mg




1998
1715
70


Ex.
E27
In




2002
1705
60


Ex.
E28
Sn




2000
1705
60


Ex.
E29
Mn




2000
1700
62


Ex.
E30
B




2005
1702
65


Ex.
E31
W




2004
1700
64


Ex.
E32
Nb




2002
1705
60


Ex.
E33
Mo




2005
1702
65


Ex.
E34
Ta
0.5
60 · 55


1750
1610
70


Ex.
E35
Al




1750
1612
72


Ex.
E36
Zr




1755
1600
65


Ex.
E37
Mg




1760
1620
68


Ex.
E38
In




1765
1625
67


Ex.
E39
Sn




1760
1630
62


Ex.
E40
Mn




1762
1625
65


Ex.
E41
B




1758
1620
67


Ex.
E42
W




1757
1615
70


Ex.
E43
Nb




1760
1630
62


Ex.
E44
Mo




1758
1620
67
















TABLE 5B







First Lithium-Nickel Composite Oxide: LiNi0.90Co0.10O2

















Internal Short







Circuit Safety



Environment to


Discharge
60° C.-Crush Speed



be Allowed to


Performance
5 mm/Sec



Stand


Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
e1
Ta
0.5
25 · 20
Dry Air
Oxygen
2004
1900
118


Comp. Ex.
e2
Al




2005
1900
119


Comp. Ex.
e3
Zr




2000
1905
120


Comp. Ex.
e4
Mg




2000
1905
115


Comp. Ex.
e5
In




2002
1902
114


Comp. Ex.
e6
Sn




2000
1902
112


Comp. Ex.
e7
Mn




2003
1902
110


Comp. Ex.
e8
B




2005
1900
120


Comp. Ex.
e9
W




2005
1905
115


Comp. Ex.
e10
Nb




2003
1902
110


Comp. Ex.
e11
Mo




2002
1902
114


Comp. Ex.
e12
Ta

25 · 55
Oxygen

2000
1902
116


Comp. Ex.
e13
Al




2000
1902
114


Comp. Ex.
e14
Zr




2005
1905
118


Comp. Ex.
e15
Mg




2000
1900
117


Comp. Ex.
e16
In




1999
1905
116


Comp. Ex.
e17
Sn




1998
1902
112


Comp. Ex.
e18
Mn




1997
1903
118


Comp. Ex.
e19
B




1999
1904
116


Comp. Ex.
e20
W




2000
1904
115


Comp. Ex.
e21
Nb




1997
1903
118


Comp. Ex.
e22
Mo




1999
1905
116


Comp. Ex.
e23
Ta


Dry Air
Dry Air
2002
1900
120


Comp. Ex.
e24
Al




2002
1901
120


Comp. Ex.
e25
Zr




2004
1900
110


Comp. Ex.
e26
Mg




2003
1900
100


Comp. Ex.
e27
In




2000
1905
100


Comp. Ex.
e28
Sn




2000
1904
110


Comp. Ex.
e29
Mn




2000
1902
105


Comp. Ex.
e30
B




2003
1900
120


Comp. Ex.
e31
W




2005
1900
120


Comp. Ex.
e32
Nb




2000
1902
105


Comp. Ex.
e33
Mo




2003
1900
120


Comp. Ex.
e34
Not
—
25 · 55

Oxygen
1750
1600
72




Added





















Comp. Ex.
e35
Not
0.5
Not Carried Out
2000
1900
114


Comp. Ex.
e36
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
2005
1901
112






(molar ratio)









treated at 400° C. for 6 hours





Comp. Ex.
e37


Not Carried Out
2005
1905
120









EXAMPLE 6
A first lithium-nickel composite oxide having a composition of LiNi0.50Co0.50O2 was obtained by using nickel sulfate and cobalt sulfate without using aluminum sulfate so that a molar ratio of Ni atoms and Co atoms was 50:50 upon synthesizing the first lithium-nickel composite oxide. Example Batteries F1 to F44 and Comparative Example Batteries f1 to f37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 6A and 6B.







TABLE 6A







First Lithium-Nickel Composite Oxide: LiNi0.50Co0.50O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Ex.
F1
Ta
0.5
25 · 55
Dry Air
Oxygen
2000
1900
60


Ex.
F2

2.0



2000
1905
62


Ex.
F3
Al
0.5



2004
1902
65


Ex.
F4

2.0



2002
1900
61


Ex.
F5
Zr
0.5



2000
1902
70


Ex.
F6

2.0



2000
1900
65


Ex.
F7
Mg
0.5



1999
1900
61


Ex.
F8

2.0



1998
1905
62


Ex.
F9
In
0.5



2002
1900
64


Ex.
F10

2.0



2000
1900
68


Ex.
F11
Sn
0.5



2000
1905
66


Ex.
F12

2.0



2005
1904
62


Ex.
F13
Mn
0.5



2000
1902
61


Ex.
F14

2.0



2004
1902
62


Ex.
F15
B
0.5



2002
1900
65


Ex.
F16

2.0



1999
1910
64


Ex.
F17
W
0.5



2002
1910
66


Ex.
F18

2.0



2000
1915
65


Ex.
F19
Nb
0.5



2000
1905
66


Ex.
F20

2.0



2002
1900
65


Ex.
F21
Mo
0.5



2000
1900
65


Ex.
F22

2.0



2004
1902
65


Ex.
F23
Ta
2.5



2000
1700
69


Ex.
F24
Al




2002
1702
67


Ex.
F25
Zr




1999
1710
65


Ex.
F26
Mg




1998
1715
68


Ex.
F27
In




2002
1705
64


Ex.
F28
Sn




2000
1705
66


Ex.
F29
Mn




2000
1700
65


Ex.
F30
B




2005
1702
64


Ex.
F31
W




2004
1700
65


Ex.
F32
Nb




2002
1705
64


Ex.
F33
Mo




2000
1700
65


Ex.
F34
Ta
0.5
60 · 55


1780
1600
62


Ex.
F35
Al




1770
1620
65


Ex.
F36
Zr




1720
1650
63


Ex.
F37
Mg




1780
1680
67


Ex.
F38
In




1760
1630
64


Ex.
F39
Sn




1790
1620
62


Ex.
F40
Mn




1760
1680
65


Ex.
F41
B




1750
1650
65


Ex.
F42
W




1780
1650
65


Ex.
F43
Nb




1780
1680
67


Ex.
F44
Mo




1790
1620
62
















TABLE 6B







First Lithium-Nickel Composite Oxide: LiNi0.50Co0.50O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Comp. Ex.
f1
Ta
0.5
25 · 20
Dry Air
Oxygen
2004
1900
120


Comp. Ex.
f2
Al




2005
1900
110


Comp. Ex.
f3
Zr




2000
1905
115


Comp. Ex.
f4
Mg




2000
1905
112


Comp. Ex.
f5
In




2002
1902
114


Comp. Ex.
f6
Sn




2000
1902
112


Comp. Ex.
f7
Mn




2003
1902
112


Comp. Ex.
f8
B




2005
1900
125


Comp. Ex.
f9
W




2005
1905
120


Comp. Ex.
f10
Nb




2002
1902
114


Comp. Ex.
f11
Mo




2003
1902
112


Comp. Ex.
f12
Ta

25 · 55
Oxygen

2000
1902
116


Comp. Ex.
f13
Al




2000
1902
118


Comp. Ex.
f14
Zr




2005
1905
110


Comp. Ex.
f15
Mg




2000
1900
112


Comp. Ex.
f16
In




1999
1905
115


Comp. Ex.
f17
Sn




1998
1902
115


Comp. Ex.
f18
Mn




1997
1903
118


Comp. Ex.
f19
B




1999
1904
117


Comp. Ex.
f20
W




2000
1904
119


Comp. Ex.
f21
Nb




1999
1905
115


Comp. Ex.
f22
Mo




1997
1903
118


Comp. Ex.
f23
Ta


Dry Air
Dry Air
2002
1900
110


Comp. Ex.
f24
Al




2002
1901
110


Comp. Ex.
f25
Zr




2004
1900
115


Comp. Ex.
f26
Mg




2003
1900
117


Comp. Ex.
f27
In




2000
1905
118


Comp. Ex.
f28
Sn




2000
1904
116


Comp. Ex.
f29
Mn




2000
1902
120


Comp. Ex.
f30
B




2003
1900
120


Comp. Ex.
f31
W




2005
1900
115


Comp. Ex.
f32
Nb




2000
1902
120


Comp. Ex.
f33
Mo




2000
1904
116


Comp. Ex.
f34
Not Added
—
25 · 55

Oxygen
1710
1600
 60














Comp. Ex.
f35
Not Added
0.5
Not Carried Out
2000
1900
112


Comp. Ex.
f36

—
Mixed Gas of Nitrogen:Hydrogen = 95:5
2005
1901
110






(molar ratio)






treated at 400° C. for 6 hours


Comp. Ex.
f37


Not Carried Out
2005
1905
130









EXAMPLE 7
Nickel sulfate, cobalt sulfate, and aluminum sulfate were mixed so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 80:15:3. The obtained mixture in an amount of 3.2 kg was dissolved in 10 L of water, to obtain a raw material solution. To the raw material solution, 400 g of sodium hydroxide was added to form a precipitate. The precipitate was sufficiently washed with water and dried, to obtain a coprecipitated hydroxide.
To 3 kg of the obtained coprecipitated hydroxide of Ni—Co—Al, 853 g of lithium hydroxide and 378 g of manganese nitrate were mixed. The obtained mixture was baked at a synthesizing temperature of 750° C. for 10 hours under an atmosphere with an oxygen partial pressure of 0.5 atm, to obtain a first lithium-nickel composite oxide including Al and Mn as element Me (composition: LiNi0.8Cu0.15Al0.03Mn0.02O2).
Example Batteries G1 to G44 and Comparative Example Batteries g1 to g37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 7A and 7B.







TABLE 7A







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Mn0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Ex.
G1
Ta
0.5
25 · 55
Dry Air
Oxygen
2002
1905
62


Ex.
G2

2.0



2004
1900
65


Ex.
G3
Al
0.5



2005
1902
66


Ex.
G4

2.0



2002
1905
60


Ex.
G5
Zr
0.5



2000
1900
68


Ex.
G6

2.0



2000
1900
68


Ex.
G7
Mg
0.5



2000
1900
64


Ex.
G8

2.0



2002
1900
64


Ex.
G9
In
0.5



2004
1900
64


Ex.
G10

2.0



2003
1902
66


Ex.
G11
Sn
0.5



2002
1900
66


Ex.
G12

2.0



2004
1904
66


Ex.
G13
Mn
0.5



2000
1910
60


Ex.
G14

2.0



2000
1915
60


Ex.
G15
B
0.5



2000
1900
61


Ex.
G16

2.0



2002
1910
61


Ex.
G17
W
0.5



2000
1910
62


Ex.
G18

2.0



2004
1915
62


Ex.
G19
Nb
0.5



2001
1900
68


Ex.
G20

2.0



2002
1905
68


Ex.
G21
Mo
0.5



2000
1902
67


Ex.
G22

2.0



2000
1902
67


Ex.
G23
Ta
2.5



2002
1705
64


Ex.
G24
Al




2004
1715
66


Ex.
G25
Zr




2004
1705
65


Ex.
G26
Mg




2004
1715
65


Ex.
G27
In




2004
1702
64


Ex.
G28
Sn




2000
1700
64


Ex.
G29
Mn




2005
1700
66


Ex.
G30
B




2005
1702
65


Ex.
G31
W




2005
1700
65


Ex.
G32
Nb




2000
1700
65


Ex.
G33
Mo




2000
1705
64


Ex.
G34
Ta
0.5
60 · 55


1760
1660
65


Ex.
G35
Al




1750
1680
65


Ex.
G36
Zr




1760
1678
64


Ex.
G37
Mg




1780
1670
67


Ex.
G38
In




1750
1655
62


Ex.
G39
Sn




1750
1675
60


Ex.
G40
Mn




1780
1677
60


Ex.
G41
B




1760
1682
62


Ex.
G42
W




1780
1685
62


Ex.
G43
Nb




1780
1678
65


Ex.
G44
Mo




1790
1679
65
















TABLE 7B







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Mn0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Comp. Ex.
g1
Ta
0.5
25 · 20
Dry Air
Oxygen
2002
1905
125


Comp. Ex.
g2
Al




2004
1902
115


Comp. Ex.
g3
Zr




2002
1900
110


Comp. Ex.
g4
Mg




2002
1900
110


Comp. Ex.
g5
In




2000
1905
120


Comp. Ex.
g6
Sn




2000
1900
120


Comp. Ex.
g7
Mn




2004
1902
120


Comp. Ex.
g8
B




2004
1905
110


Comp. Ex.
g9
W




2002
1900
120


Comp. Ex.
g10
Nb




2004
1905
110


Comp. Ex.
g11
Mo




2004
1905
110


Comp. Ex.
g12
Ta

25 · 55
Oxygen

2000
1900
115


Comp. Ex.
g13
Al




2000
1900
120


Comp. Ex.
g14
Zr




2004
1902
110


Comp. Ex.
g15
Mg




2005
1900
120


Comp. Ex.
g16
In




2000
1900
120


Comp. Ex.
g17
Sn




2005
1902
120


Comp. Ex.
g18
Mn




2004
1905
120


Comp. Ex.
g19
B




2002
1902
120


Comp. Ex.
g20
W




2002
1904
120


Comp. Ex.
g21
Nb




2000
1900
115


Comp. Ex.
g22
Mo




2000
1900
118


Comp. Ex.
g23
Ta


Dry Air
Dry Air
2004
1902
115


Comp. Ex.
g24
Al




2005
1900
118


Comp. Ex.
g25
Zr




2005
1905
116


Comp. Ex.
g26
Mg




2000
1902
117


Comp. Ex.
g27
In




2002
1904
120


Comp. Ex.
g28
Sn




2002
1905
120


Comp. Ex.
g29
Mn




2002
1900
110


Comp. Ex.
g30
B




2004
1902
110


Comp. Ex.
g31
W




2004
1904
115


Comp. Ex.
g32
Nb




2004
1900
110


Comp. Ex.
g33
Mo




2004
1900
115


Comp. Ex.
g34
Not Added
—
25 · 55

Oxygen
1720
1605
 65














Comp. Ex.
g35
Not Added
0.5
Not Carried Out
2002
1905
120


Comp. Ex.
g36

—
Mixed Gas of Nitrogen:Hydrogen = 95:5
2004
1900
115






(molar ratio)






treated at 400° C. for 6 hours


Comp. Ex.
g37


Not Carried Out
2004
1902
127









EXAMPLE 8
To 3 kg of a coprecipitated hydroxide of Ni—Co—Al prepared in the same manner as Example 7, 853 g of lithium hydroxide and 378 g of magnesium sulfate were mixed. The obtained mixture was baked at a synthesizing temperature of 750° C. for 10 hours under an atmosphere with an oxygen partial pressure of 0.5 atm, to obtain a first lithium-nickel composite oxide including Al and Mg as element Me (composition: LiNi0.8Co0.15Al0.03Mg0.02O2).
Example Batteries H1 to H44 and Comparative Example Batteries h1 to h37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 8A and 8B.







TABLE 8A







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Mg0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Ex.
H1
Ta
0.5
25 · 55
Dry Air
Oxygen
2005
1904
67


Ex.
H2

2.0



2004
1905
64


Ex.
H3
Al
0.5



2003
1904
65


Ex.
H4

2.0



2000
1903
64


Ex.
H5
Zr
0.5



2002
1902
64


Ex.
H6

2.0



2004
1904
68


Ex.
H7
Mg
0.5



2006
1900
61


Ex.
H8

2.0



2004
1903
62


Ex.
H9
In
0.5



2003
1905
67


Ex.
H10

2.0



2008
1902
64


Ex.
H11
Sn
0.5



2004
1904
62


Ex.
H12

2.0



2006
1905
62


Ex.
H13
Mn
0.5



2004
1904
63


Ex.
H14

2.0



2005
1905
64


Ex.
H15
B
0.5



2002
1906
67


Ex.
H16

2.0



2000
1903
62


Ex.
H17
W
0.5



2001
1901
69


Ex.
H18

2.0



2003
1901
67


Ex.
H19
Nb
0.5



2004
1904
65


Ex.
H20

2.0



2005
1902
61


Ex.
H21
Mo
0.5



2006
1905
62


Ex.
H22

2.0



2004
1903
64


Ex.
H23
Ta
2.5



2002
1705
65


Ex.
H24
Al




2000
1702
63


Ex.
H25
Zr




2006
1704
64


Ex.
H26
Mg




2004
1705
66


Ex.
H27
In




2005
1706
66


Ex.
H28
Sn




2004
1709
66


Ex.
H29
Mn




2003
1705
67


Ex.
H30
B




2005
1701
62


Ex.
H31
W




2004
1700
63


Ex.
H32
Nb




2006
1705
64


Ex.
H33
Mo




2004
1704
65


Ex.
H34
Ta
0.5
60 · 55


1780
1610
62


Ex.
H35
Al




1778
1620
60


Ex.
H36
Zr




1778
1640
60


Ex.
H37
Mg




1772
1670
62


Ex.
H38
In




1772
1650
62


Ex.
H39
Sn




1777
1620
63


Ex.
H40
Mn




1778
1640
62


Ex.
H41
B




1776
1650
61


Ex.
H42
W




1777
1670
63


Ex.
H43
Nb




1775
1640
64


Ex.
H44
Mo




1778
1650
62
















TABLE 8B







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Mg0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Comp. Ex.
h1
Ta
0.5
25 · 20
Dry Air
Oxygen
2000
1904
125


Comp. Ex.
h2
Al




2002
1902
120


Comp. Ex.
h3
Zr




2005
1904
124


Comp. Ex.
h4
Mg




2004
1905
123


Comp. Ex.
h5
In




2003
1904
125


Comp. Ex.
h6
Sn




2005
1906
124


Comp. Ex.
h7
Mn




2004
1900
126


Comp. Ex.
h8
B




2001
1905
120


Comp. Ex.
h9
W




2003
1904
125


Comp. Ex.
h10
Nb




2006
1902
121


Comp. Ex.
h11
Mo




2005
1904
123


Comp. Ex.
h12
Ta

25 · 55
Oxygen

2003
1903
118


Comp. Ex.
h13
Al




2003
1904
115


Comp. Ex.
h14
Zr




2006
1905
114


Comp. Ex.
h15
Mg




2004
1904
116


Comp. Ex.
h16
In




2000
1903
114


Comp. Ex.
h17
Sn




2000
1904
118


Comp. Ex.
h18
Mn




2005
1900
119


Comp. Ex.
h19
B




2003
1900
116


Comp. Ex.
h20
W




2001
1900
117


Comp. Ex.
h21
Nb




2005
1905
112


Comp. Ex.
h22
Mo




2004
1904
120


Comp. Ex.
h23
Ta


Dry Air
Dry Air
2003
1902
115


Comp. Ex.
h24
Al




2005
1902
110


Comp. Ex.
h25
Zr




2006
1903
115


Comp. Ex.
h26
Mg




2003
1904
114


Comp. Ex.
h27
In




2004
1905
118


Comp. Ex.
h28
Sn




2000
1904
119


Comp. Ex.
h29
Mn




2000
1904
119


Comp. Ex.
h30
B




2005
1900
116


Comp. Ex.
h31
W




2003
1901
114


Comp. Ex.
h32
Nb




2006
1900
115


Comp. Ex.
h33
Mo




2004
1900
118


Comp. Ex.
h34
Not Added
—
25 · 55

Oxygen
1712
1605
 62














Comp. Ex.
h35
Not Added
0.5
Not Carried Out
2005
1904
115


Comp. Ex.
h36

—
Mixed Gas of Nitrogen:Hydrogen = 95:5
2002
1900
118






(molar ratio)






treated at 400° C. for 6 hours


Comp. Ex.
h37


Not Carried Out
2002
1900
125









EXAMPLE 9
To 3 kg of a coprecipitated hydroxide of Ni—Co—Al prepared in the same manner as Example 7, 853 g of lithium hydroxide and 378 g of calcium hydroxide were mixed. The obtained mixture was baked under an atmosphere with an oxygen partial pressure of 0.5 atm at a synthesizing temperature of 750° C. for 10 hours, to obtain a first lithium-nickel composite oxide including Al and Ca as element Me (composition: LiNi0.8Co0.15Al0.03Ca0.02O2).
Example Batteries I1 to I44 and Comparative Example Batteries i1 to i37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 9A and 9B.







TABLE 9A







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Ca0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Ex.
I1
Ta
0.5
25 · 55
Dry Air
Oxygen
2005
1905
62


Ex.
I2

2.0



2000
1902
64


Ex.
I3
Al
0.5



2002
1900
65


Ex.
I4

2.0



2005
1905
66


Ex.
I5
Zr
0.5



2000
1904
68


Ex.
I6

2.0



2002
1903
64


Ex.
I7
Mg
0.5



2004
1905
62


Ex.
I8

2.0



2005
1900
60


Ex.
I9
In
0.5



2005
1902
64


Ex.
I10

2.0



2005
1905
68


Ex.
I11
Sn
0.5



2002
1904
62


Ex.
I12

2.0



2004
1905
62


Ex.
I13
Mn
0.5



2004
1904
64


Ex.
I14

2.0



2000
1902
67


Ex.
I15
B
0.5



2002
1900
68


Ex.
I16

2.0



2005
1902
65


Ex.
I17
W
0.5



2003
1905
62


Ex.
I18

2.0



2003
1904
64


Ex.
I19
Nb
0.5



2004
1904
62


Ex.
I20

2.0



2000
1900
62


Ex.
I21
Mo
0.5



2002
1905
61


Ex.
I22

2.0



2005
1900
62


Ex.
I23
Ta
2.5



2000
1705
67


Ex.
I24
Al




2005
1705
68


Ex.
I25
Zr




2000
1708
64


Ex.
I26
Mg




2000
1707
68


Ex.
I27
In




2005
1707
64


Ex.
I28
Sn




2002
1709
65


Ex.
I29
Mn




2004
1707
69


Ex.
I30
B




2002
1709
67


Ex.
I31
W




2000
1707
65


Ex.
I32
Nb




2000
1705
64


Ex.
I33
Mo




2002
1701
68


Ex.
I34
Ta
0.5
60 · 55


1785
1650
65


Ex.
I35
Al




1775
1670
64


Ex.
I36
Zr




1725
1680
65


Ex.
I37
Mg




1770
1670
67


Ex.
I38
In




1770
1675
67


Ex.
I39
Sn




1780
1672
62


Ex.
I40
Mn




1750
1678
64


Ex.
I41
B




1740
1682
64


Ex.
I42
W




1770
1668
68


Ex.
I43
Nb




1770
1680
68


Ex.
I44
Mo




1790
1678
62
















TABLE 9B







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Ca0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Comp. Ex.
i1
Ta
0.5
25 · 20
Dry Air
Oxygen
2002
1902
125


Comp. Ex.
i2
Al




2004
1905
124


Comp. Ex.
i3
Zr




2002
1900
123


Comp. Ex.
i4
Mg




2002
1904
123


Comp. Ex.
i5
In




2000
1905
124


Comp. Ex.
i6
Sn




2005
1900
120


Comp. Ex.
i7
Mn




2004
1900
118


Comp. Ex.
i8
B




2005
1905
119


Comp. Ex.
i9
W




2004
1902
117


Comp. Ex.
i10
Nb




2004
1905
121


Comp. Ex.
i11
Mo




2004
1905
120


Comp. Ex.
i12
Ta

25 · 55
Oxygen

2002
1900
118


Comp. Ex.
i13
Al




2002
1904
120


Comp. Ex.
i14
Zr




2002
1904
122


Comp. Ex.
i15
Mg




2000
1905
123


Comp. Ex.
i16
In




2000
1904
124


Comp. Ex.
i17
Sn




2002
1902
125


Comp. Ex.
i18
Mn




2000
1900
125


Comp. Ex.
i19
B




2000
1901
124


Comp. Ex.
i20
W




2002
1902
119


Comp. Ex.
i21
Nb




2000
1903
119


Comp. Ex.
i22
Mo




2000
1903
120


Comp. Ex.
i23
Ta


Dry Air
Dry Air
2005
1905
118


Comp. Ex.
i24
Al




2004
1902
112


Comp. Ex.
i25
Zr




2002
1905
114


Comp. Ex.
i26
Mg




2000
1904
118


Comp. Ex.
i27
In




2003
1905
116


Comp. Ex.
i28
Sn




2003
1906
117


Comp. Ex.
i29
Mn




2005
1905
118


Comp. Ex.
i30
B




2004
1903
118


Comp. Ex.
i31
W




2005
1900
119


Comp. Ex.
i32
Nb




2002
1900
121


Comp. Ex.
i33
Mo




2000
1902
122


Comp. Ex.
i34
Not Added
—
25 · 55

Oxygen
1715
1605
 59














Comp. Ex.
i35
Not Added
0.5
Not Carried Out
2005
1904
120


Comp. Ex.
i36

—
Mixed Gas of Nitrogen:Hydrogen = 95:5
2000
1900
115






(molar ratio)






treated at 400° C. for 6 hours


Comp. Ex.
i37


Not Carried Out
2000
1905
129









EXAMPLE 10
To 3 kg of a coprecipitated hydroxide of Ni—Co—Al prepared in the same manner as Example 7, 853 g of lithium hydroxide and 378 g of titanium sulfate were mixed. The obtained mixture was baked under an atmosphere with an oxygen partial pressure of 0.5 atm, and at a synthesizing temperature of 750° C. for 10 hours, to obtain a first lithium-nickel composite oxide including Al and Ti as element Me (composition: LiNi0.8Co0.15Al0.03Ti0.02O2).
Example Batteries J1 to J44 and Comparative Example Batteries j1 to j37 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 10A and 10B.







TABLE 10A







Lithium Composite Oxide: LiNi0.80Co0.15Al0.03Ti0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Ex.
J1
Ta
0.5
25 · 55
Dry Air
Oxygen
2000
1905
64


Ex.
J2

2.0



2004
1902
62


Ex.
J3
Al
0.5



2005
1903
64


Ex.
J4

2.0



2002
1904
65


Ex.
J5
Zr
0.5



2000
1903
62


Ex.
J6

2.0



2003
1902
62


Ex.
J7
Mg
0.5



2005
1902
60


Ex.
J8

2.0



2000
1904
60


Ex.
J9
In
0.5



2000
1902
62


Ex.
J10

2.0



2002
1903
62


Ex.
J11
Sn
0.5



2001
1904
61


Ex.
J12

2.0



2006
1905
63


Ex.
J13
Mn
0.5



2003
1900
64


Ex.
J14

2.0



2004
1902
61


Ex.
J15
B
0.5



2000
1903
62


Ex.
J16

2.0



2002
1900
60


Ex.
J17
W
0.5



2002
1900
60


Ex.
J18

2.0



2004
1905
63


Ex.
J19
Nb
0.5



2002
1904
65


Ex.
J20

2.0



2003
1900
64


Ex.
J21
Mo
0.5



2006
1902
62


Ex.
J22

2.0



2005
1900
62


Ex.
J23
Ta
2.5



2002
1705
60


Ex.
J24
Al




2004
1705
64


Ex.
J25
Zr




2005
1708
64


Ex.
J26
Mg




2002
1710
68


Ex.
J27
In




2000
1708
66


Ex.
J28
Sn




2002
1704
67


Ex.
J29
Mn




2004
1702
68


Ex.
J30
B




2006
1700
64


Ex.
J31
W




2003
1705
65


Ex.
J32
Nb




2002
1702
64


Ex.
J33
Mo




2002
1705
68


Ex.
J34
Ta
0.5
60 · 55


1780
1615
65


Ex.
J35
Al




1778
1625
64


Ex.
J36
Zr




1779
1637
62


Ex.
J37
Mg




1775
1650
68


Ex.
J38
In




1777
1625
67


Ex.
J39
Sn




1778
1620
65


Ex.
J40
Mn




1777
1650
62


Ex.
J41
B




1778
1630
64


Ex.
J42
W




1780
1640
68


Ex.
J43
Nb




1781
1650
67


Ex.
J44
Mo




1782
1640
68
















TABLE 10B







First Lithium-Nickel Composite Oxide: LiNi0.80Co0.15Al0.03Ti0.02O2












Environment

Discharge
Internal Short



to be Allowed

Performance
Circuit Safety



to Stand

Discharge
60° C. · Crush

















Amount
Temperature ·
Preliminary
Main Baking ·
400 mA
4000 mA
Speed 5 mm/Sec


Battery
Element
Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Highest Temperature


No
M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
Reached (° C.)



















Comp. Ex.
j1
Ta
0.5
25 · 20
Dry Air
Oxygen
2000
1904
117


Comp. Ex.
j2
Al




2004
1905
115


Comp. Ex.
j3
Zr




2002
1904
120


Comp. Ex.
j4
Mg




2005
1900
120


Comp. Ex.
j5
In




2004
1905
115


Comp. Ex.
j6
Sn




2000
1900
117


Comp. Ex.
j7
Mn




2002
1902
117


Comp. Ex.
j8
B




2003
1902
115


Comp. Ex.
j9
W




2005
1900
117


Comp. Ex.
j10
Nb




2004
1905
112


Comp. Ex.
j11
Mo




2005
1900
115


Comp. Ex.
j12
Ta

25 · 55
Oxygen

2002
1904
114


Comp. Ex.
j13
Al




2002
1900
115


Comp. Ex.
j14
Zr




2000
1903
118


Comp. Ex.
j15
Mg




2005
1903
119


Comp. Ex.
j16
In




2002
1902
117


Comp. Ex.
j17
Sn




2004
1902
111


Comp. Ex.
j18
Mn




2003
1900
112


Comp. Ex.
j19
B




2002
1905
115


Comp. Ex.
j20
W




2002
1900
110


Comp. Ex.
j21
Nb




2000
1900
120


Comp. Ex.
j22
Mo




2000
1900
125


Comp. Ex.
j23
Ta


Dry Air
Dry Air
2004
1904
111


Comp. Ex.
j24
Al




2005
1900
117


Comp. Ex.
j25
Zr




2006
1905
115


Comp. Ex.
j26
Mg




2004
1900
111


Comp. Ex.
j27
In




2002
1900
112


Comp. Ex.
j28
Sn




2002
1905
115


Comp. Ex.
j29
Mn




2000
1904
111


Comp. Ex.
j30
B




2003
1902
111


Comp. Ex.
j31
W




2005
1900
115


Comp. Ex.
j32
Nb




2002
1904
117


Comp. Ex.
j33
Mo




2002
1907
117


Comp. Ex.
j34
Not Added
—
25 · 55

Oxygen
1710
1607
 67














Comp. Ex.
j35
Not Added
0.5
Not Carried Out
2005
1907
117


Comp. Ex.
j36

—
Mixed Gas of Nitrogen:Hydrogen = 95:5
2004
1907
115






(molar ratio)






treated at 400° C. for 6 hours


Comp. Ex.
j37


Not Carried Out
2002
1907
124









The results in Table 2A to 10A, and in Tables 2B to 10B showed almost the same tendency with the case of Example 1.
COMPARATIVE EXAMPLE 1
A first lithium-nickel composite oxide having a composition of LiNi0.20Co0.50Al0.30O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 20:50:30 upon synthesizing the first lithium-nickel composite oxide. Comparative Example Batteries k1 to k81 were prepared in the same manner as Example Batteries A1 to 44 and Comparative Example Batteries a1 to 37, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 11A and 11B.







TABLE 11A







First Lithium-Nickel Composite Oxide: LiNi0.20Co0.50Al0.30O2















Internal






Short Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be Allowed

Performance
5 mm/Sec



to Stand

Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
k1
Ta
0.5
25 · 55
Dry Air
Oxygen
1800
1710
117


Comp. Ex.
k2

2.0



1805
1720
115


Comp. Ex.
k3
Al
0.5



1804
1715
117


Comp. Ex.
k4

2.0



1805
1710
112


Comp. Ex.
k5
Zr
0.5



1802
1710
115


Comp. Ex.
k6

2.0



1800
1712
117


Comp. Ex.
k7
Mg
0.5



1810
1715
120


Comp. Ex.
k8

2.0



1805
1709
118


Comp. Ex.
k9
In
0.5



1800
1708
117


Comp. Ex.
k10

2.0



1800
1710
110


Comp. Ex.
k11
Sn
0.5



1801
1710
112


Comp. Ex.
k12

2.0



1810
1712
113


Comp. Ex.
k13
Mn
0.5



1805
1715
115


Comp. Ex.
k14

2.0



1805
1715
110


Comp. Ex.
k15
B
0.5



1800
1715
120


Comp. Ex.
k16

2.0



1805
1712
118


Comp. Ex.
k17
W
0.5



1805
1710
117


Comp. Ex.
k18

2.0



1810
1715
117


Comp. Ex.
k19
Nb
0.5



1815
1710
115


Comp. Ex.
k20

2.0



1805
1705
115


Comp. Ex.
k21
Mo
0.5



1805
1700
120


Comp. Ex.
k22

2.0



1815
1715
120


Comp. Ex.
k23
Ta
2.5



1800
1530
117


Comp. Ex.
k24
Al




1800
1535
120


Comp. Ex.
k25
Zr




1805
1540
118


Comp. Ex.
k26
Mg




1807
1535
119


Comp. Ex.
k27
In




1806
1530
115


Comp. Ex.
k28
Sn




1805
1530
116


Comp. Ex.
k29
Mn




1807
1532
112


Comp. Ex.
k30
B




1806
1533
100


Comp. Ex.
k31
W




1800
1540
100


Comp. Ex.
k32
Nb




1805
1530
120


Comp. Ex.
k33
Mo




1806
1530
110


Comp. Ex.
k34
Ta
0.5
60 · 55


1805
1620
105


Comp. Ex.
k35
Al




1803
1625
100


Comp. Ex.
k36
Zr




1804
1610
110


Comp. Ex.
k37
Mg




1805
1605
112


Comp. Ex.
k38
In




1818
1605
105


Comp. Ex.
k39
Sn




1810
1600
106


Comp. Ex.
k40
Mn




1810
1620
110


Comp. Ex.
k41
B




1805
1622
110


Comp. Ex.
k42
W




1805
1600
105


Comp. Ex.
k43
Nb




1800
1600
120


Comp. Ex.
k44
Mo




1804
1610
116
















TABLE 11B







First Lithium-Nickel Composite Oxide: LiNi0.20Co0.50Al0.30O2















Internal






Short Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be Allowed

Performance
5 mm/Sec



to Stand

Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
k45
Ta
0.5
25 · 20
Dry Air
Oxygen
1800
1710
120


Comp. Ex.
k46
Al




1805
1715
120


Comp. Ex.
k47
Zr




1804
1710
115


Comp. Ex.
k48
Mg




1802
1712
115


Comp. Ex.
k49
In




1802
1712
110


Comp. Ex.
k50
Sn




1805
1710
120


Comp. Ex.
k51
Mn




1804
1715
120


Comp. Ex.
k52
B




1802
1710
122


Comp. Ex.
k53
W




1802
1715
125


Comp. Ex.
k54
Nb




1805
1711
118


Comp. Ex.
k55
Mo




1805
1710
118


Comp. Ex.
k56
Ta

25 · 55
Oxygen

1805
1717
122


Comp. Ex.
k57
Al




1802
1717
123


Comp. Ex.
k58
Zr




1803
1717
124


Comp. Ex.
k59
Mg




1805
1715
122


Comp. Ex.
k60
In




1805
1710
120


Comp. Ex.
k61
Sn




1802
1712
125


Comp. Ex.
k62
Mn




1810
1715
124


Comp. Ex.
k63
B




1805
1712
125


Comp. Ex.
k64
W




1807
1710
123


Comp. Ex.
k65
Nb




1800
1710
122


Comp. Ex.
k66
Mo




1800
1710
122


Comp. Ex.
k67
Ta


Dry Air
Dry Air
1801
1710
115


Comp. Ex.
k68
Al




1805
1710
115


Comp. Ex.
k69
Zr




1807
1712
112


Comp. Ex.
k70
Mg




1801
1715
110


Comp. Ex.
k71
In




1805
1715
111


Comp. Ex.
k72
Sn




1806
1712
112


Comp. Ex.
k73
Mn




1800
1712
117


Comp. Ex.
k74
B




1800
1710
115


Comp. Ex.
k75
W




1800
1715
115


Comp. Ex.
k76
Nb




1805
1715
120


Comp. Ex.
k77
Mo




1800
1718
115


Comp. Ex.
k78
Not Added
—
25 · 55

Oxygen
1800
1600
115














Comp. Ex.
k79
Not
0.5
Not Carried Out
1802
1710
120


Comp. Ex.
k80
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
1800
1710
120






treated at 400° C. for 6 hours


Comp. Ex.
k81


Not Carried Out
1810
1715
135









No generation of Ni1-δO was confirmed as the active material particles of each battery were analyzed. The results of Tables 7A and 7B show that in the first lithium-nickel composite oxide represented by the general formula LixNi1-y-zCoyMezO2, when y+z exceeds 0.75, Ni1-δO (0≦δ) is not generated and great amount of heat generates in the crush test.
COMPARATIVE EXAMPLE 2
Comparative Example Batteries l1 to l81 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a37, respectively, except that instead of the first lithium-nickel composite oxide, LiNiO2 was used for the raw material of the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Tables 12A and 12B.







TABLE 12A







First Lithium-Nickel Composite Oxide: LiNiO2















Internal






Short






Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be Allowed

Performance
5 mm/Sec



to Stand

Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
l1
Ta
0.5
25 · 55
Dry Air
Oxygen
1800
1710
117


Comp. Ex.
l2

2.0



1805
1720
115


Comp. Ex.
l3
Al
0.5



1804
1715
117


Comp. Ex.
l4

2.0



1805
1710
112


Comp. Ex.
l5
Zr
0.5



1802
1710
115


Comp. Ex.
l6

2.0



1800
1712
117


Comp. Ex.
l7
Mg
0.5



1810
1715
120


Comp. Ex.
l8

2.0



1805
1709
118


Comp. Ex.
l9
In
0.5



1800
1708
117


Comp. Ex.
l10

2.0



1800
1710
110


Comp. Ex.
l11
Sn
0.5



1801
1710
112


Comp. Ex.
l12

2.0



1810
1712
113


Comp. Ex.
l13
Mn
0.5



1805
1715
115


Comp. Ex.
l14

2.0



1805
1715
110


Comp. Ex.
l15
B
0.5



1800
1715
120


Comp. Ex.
l16

2.0



1805
1712
118


Comp. Ex.
l17
W
0.5



1805
1710
117


Comp. Ex.
l18

2.0



1810
1715
117


Comp. Ex.
l19
Nb
0.5



1800
1710
120


Comp. Ex.
l20

2.0



1808
1715
115


Comp. Ex.
l21
Ma
0.5



1810
1715
112


Comp. Ex.
l22

2.0



1810
1710
115


Comp. Ex.
l23
Ta
2.5



1800
1530
117


Comp. Ex.
l24
Al




1800
1535
120


Comp. Ex.
l25
Zr




1805
1540
118


Comp. Ex.
l26
Mg




1807
1535
119


Comp. Ex.
l27
In




1806
1530
115


Comp. Ex.
l28
Sn




1805
1530
116


Comp. Ex.
l29
Mn




1807
1532
112


Comp. Ex.
l30
B




1806
1533
100


Comp. Ex.
l31
W




1800
1540
100


Comp. Ex.
l32
Nb




1805
1530
120


Comp. Ex.
l33
Mo




1800
1530
115


Comp. Ex.
l34
Ta
0.5
60 · 55


1805
1620
105


Comp. Ex.
l35
Al




1803
1625
100


Comp. Ex.
l36
Zr




1804
1610
110


Comp. Ex.
l37
Mg




1805
1605
112


Comp. Ex.
l38
In




1818
1605
105


Comp. Ex.
l39
Sn




1810
1600
106


Comp. Ex.
l40
Mn




1810
1620
110


Comp. Ex.
l41
B




1805
1622
110


Comp. Ex.
l42
W




1805
1600
105


Comp. Ex.
l43
Nb




1810
1620
115


Comp. Ex.
l44
Mo




1808
1610
110
















TABLE 12B







First Lithium-Nickel Composite Oxide: LiNiO2















Internal






Short






Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be Allowed

Performance
5 mm/Sec



to Stand

Discharge
Highest

















Amount
Temperature ·
Preliminary
Main Baking-
400 mA
4000 mA
Temperature


Battery

Added
Humidity
Baking
Annealing
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
(° C. · %)
Atmosphere
Atmosphere
(mAh)
(mAh)
(° C.)



















Comp. Ex.
l45
Ta
0.5
25 · 20
Dry Air
Oxygen
1800
1710
120


Comp. Ex.
l46
Al




1805
1715
120


Comp. Ex.
l47
Zr




1804
1710
115


Comp. Ex.
l48
Mg




1802
1712
115


Comp. Ex.
l49
In




1802
1712
110


Comp. Ex.
l50
Sn




1805
1710
120


Comp. Ex.
l51
Mn




1804
1715
120


Comp. Ex.
l52
B




1802
1710
122


Comp. Ex.
l53
W




1802
1715
125


Comp. Ex.
l54
Nb




1805
1710
125


Comp. Ex.
l55
Mo




1800
1710
115


Comp. Ex.
l56
Ta

25 · 55
Oxygen

1805
1717
122


Comp. Ex.
l57
Al




1802
1717
123


Comp. Ex.
l58
Zr




1803
1717
124


Comp. Ex.
l59
Mg




1805
1715
122


Comp. Ex.
l60
In




1805
1710
120


Comp. Ex.
l61
Sn




1802
1712
125


Comp. Ex.
l62
Mn




1810
1715
124


Comp. Ex.
l63
B




1805
1712
125


Comp. Ex.
l64
W




1807
1710
123


Comp. Ex.
l65
Nb




1802
1710
120


Comp. Ex.
l66
Mo




1805
1715
122


Comp. Ex.
l67
Ta


Dry Air
Dry Air
1801
1710
115


Comp. Ex.
l68
Al




1805
1710
115


Comp. Ex.
l69
Zr




1807
1712
112


Comp. Ex.
l70
Mg




1801
1715
110


Comp. Ex.
l71
In




1805
1715
111


Comp. Ex.
l72
Sn




1806
1712
112


Comp. Ex.
l73
Mn




1800
1712
117


Comp. Ex.
l74
B




1800
1710
115


Comp. Ex.
l75
W




1800
1715
115


Comp. Ex.
l76
Nb




1805
1710
118


Comp. Ex.
l77
Mo




1800
1715
117


Comp. Ex.
l78
Not Added
—
25 · 55

Oxygen
1800
1600
115














Comp. Ex.
l79
Not
0.5
Not Carried Out
1802
1710
120


Comp. Ex.
l80
Added
—
Mixed Gas of Nitrogen:Hydrogen = 95:5
1800
1710
120






(molar ratio)






treated at 400° C. for 6 hours


Comp. Ex.
l81


Not Carried Out
1810
1715
135









The results of Tables 12A and 12B show that when LiNiO2 was used, the discharge capacity becomes small though Ni1-δO (0≦δ) was produced.
When Z was greater than 0.5 in LiNi1-y-zCoyMexO2, homogeneous solid solution could not be obtained.
EXAMPLE 11
Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14 were made in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a11, a34, a36, and a37, respectively, except that the synthesizing the first lithium-nickel composite oxide and synthesizing the active material particles were carried out as below, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 13.
(i) Synthesis of First Lithium-Nickel Composite Oxide
A first lithium-nickel composite oxide including excessive lithium (Li1.03Ni0.8Co0.15Al0.05O2) was obtained in the same manner as Example 1, except that the amount of lithium hydroxide to be mixed with 3 kg of the coprecipitated hydroxide of Ni—Co—Al was increased to 800 g.
(ii) Synthesis of Active Material Particles
In the Case of Example Batteries M1 to M44 and Comparative Example Batteries m1 to m12
Active material particles were synthesized in the same manner as Example Batteries A1 to A44 and Comparative Example Batteries a1 to a11, and a34 of Example 1, except that the third step was carried out as in below. In the third step, the first lithium-nickel composite oxide with NiOOH formed on the surface thereof was baked at 650° C. for 6 hours, under 100% oxygen atmosphere (pressure 101 KPa). By this baking, NiOOH on the surface of the first lithium-nickel composite oxide reacted with the excessive Li to be converted to a second lithium-nickel composite oxide including a domain having the NaCl-type crystal structure. As a result, active material particles having a surface layer portion including element M and a second lithium-nickel composite oxide was obtained.
Presence of the second lithium-nickel composite oxide (a domain having the NaCl-type crystal structure) was confirmed by electron diffraction measurement. In Examples below as well, presence of the domain having the NaCl-type crystal structure in the active material particles was confirmed by electron diffraction measurement.
In the Case of Comparative Example Battery m13
Active material particles were synthesized in the same manner as Comparative Example Battery a36 in Example 1, except that a first lithium-nickel composite oxide including excessive lithium (Li1.03Ni0.8Co0.15Al0.05O2) was used.
In the Case of Comparative Example Battery m14
Active material particles were synthesized in the same manner as Comparative Example Battery a37 of Example 1, except that a first lithium-nickel composite oxide including excessive lithium (Li1.03Ni0.8Co0.15Al0.05O2) was used. That is, Li1.03Ni0.8Co0.15Al0.05O2 as is was used as the positive electrode active material.







TABLE 13







First Lithium-Nickel Composite Oxide: Li1.03Ni0.80Co0.15Al0.05O2















Internal






Short Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be

Performance
5 mm/Sec



Allowed to Stand

Discharge
Highest

















Amount
NaCl-type Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere-
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
M1
Ta
0.5
Present
25 · 55
Oxygen-650° C.
1982
1901
71


Ex.
M2

2.0



1984
1902
76


Ex.
M3
Al
0.5



1980
1902
72


Ex.
M4

2.0



1989
1904
70


Ex.
M5
Zr
0.5



1988
1908
68


Ex.
M6

2.0



1987
1908
62


Ex.
M7
Mg
0.5



1992
1909
71


Ex.
M8

2.0



1991
1910
72


Ex.
M9
In
0.5



1991
1912
71


Ex.
M10

2.0



1992
1915
66


Ex.
M11
Sn
0.5



1992
1910
70


Ex.
M12

2.0



1991
1908
70


Ex.
M13
Mn
0.5



1988
1902
68


Ex.
M14

2.0



1990
1901
75


Ex.
M15
B
0.5



1992
1902
71


Ex.
M16

2.0



1994
1902
74


Ex.
M17
W
0.5



1992
1901
72


Ex.
M18

2.0



1990
1905
72


Ex.
M19
Nb
0.5



1982
1904
71


Ex.
M20

2.0



1988
1902
70


Ex.
M21
Mo
0.5



1991
1904
66


Ex.
M22

2.0



1991
1906
71


Ex.
M23
Ta
2.5



1992
1800
75


Ex.
M24
Al




1990
1802
77


Ex.
M25
Zr




1988
1801
74


Ex.
M26
Mg




1981
1800
72


Ex.
M27
In




1984
1802
71


Ex.
M28
Sn




1988
1800
65


Ex.
M29
Mn




1989
1804
69


Ex.
M30
B




1990
1805
72


Ex.
M31
W




1991
1805
69


Ex.
M32
Nb




1992
1804
72


Ex.
M33
Mo




1992
1810
71


Ex.
M34
Ta
0.5

60 · 55

1801
1700
71


Ex.
M35
Al




1800
1689
70


Ex.
M36
Zr




1805
1700
69


Ex.
M37
Mg




1815
1710
69


Ex.
M38
In




1802
1712
69


Ex.
M39
Sn




1800
1715
71


Ex.
M40
Mn




1804
1700
70


Ex.
M41
B




1804
1702
72


Ex.
M42
W




1805
1699
68


Ex.
M43
Nb




1806
1698
69


Ex.
M44
Mo




1805
1700
68


Comp. Ex.
m1
Ta
0.5
Absent
25 · 20

1991
1915
118


Comp. Ex.
m2
Al




1992
1910
119


Comp. Ex.
m3
Zr




1988
1915
121


Comp. Ex.
m4
Mg




1991
1912
115


Comp. Ex.
m5
In




1992
1900
116


Comp. Ex.
m6
Sn




1988
1911
121


Comp. Ex.
m7
Mn




1989
1907
120


Comp. Ex.
m8
B




1989
1905
125


Comp. Ex.
m9
W




1990
1901
124


Comp. Ex.
m10
Nb




1990
1900
118


Comp. Ex.
m11
Mo




1995
1900
119


Comp. Ex.
m12
Absent
—
Present
25 · 55

1750
1600
70















Comp. Ex.
m13


Absent
Mixed Gas of
2002
1900
120







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at







400° C. for 6 hours


Comp. Ex.
m14



Not Carried Out
2004
1910
125









The evaluation results are shown below.
In Example Batteries M1 to M22, in which the surface layer portion includes element M and the second lithium-nickel composite oxide, and in which the amount of element M relative to the first lithium-nickel composite oxide is 0.5 mol % or 2 mol %, the heat generation was quite small in the crush test. In these batteries, the discharge capacity with 2 CmA discharge at 0° C. is the same level as that of Comparative Example Battery m14, in which the first lithium-nickel composite oxide was used as is.
In Example Batteries M23 to M33, in which the amount of element M relative to the first lithium-nickel composite oxide was 2.5 mol %, the discharge capacity with 2 CmA discharge at 0° C. declined. Probably due to the compound of element M included in the surface layer portion and the second lithium-nickel composite oxide not being electrochemically active, it became resistance.
In Example Batteries M34 to M44, in which a condition for allowing the first lithium-nickel composite oxide carrying element M before baking to stand was changed to give high temperature, the discharge capacity tended to become low. This is probably because the portion other than the side reaction active points of the first lithium-nickel composite oxide was converted to a domain having the NaCl-type crystal structure.
In Comparative Example Battery m12, in which the first lithium-nickel composite oxide baked after being allowed to stand without carrying element M at a temperature of 25° C. and a humidity of 55% for 24 hours, the discharge capacity was not sufficient. This is probably because absence of element M at the surface thereof caused the first lithium-nickel composite oxide to deteriorate.
In Comparative Example Batteries m1 to 11, in which a condition for allowing the first lithium-nickel composite oxide carrying element M before baking to stand was changed to give low humidity, a large degree of heat generation was caused in the crush test. This is probably because the domain having the NaCl-type crystal structure which inactivate the side reaction active points of the first lithium-nickel composite oxide was not produced.
In Comparative Example Battery m13, in which the positive electrode active material with the reduced layer formed on the first lithium-nickel composite oxide surface, the discharge capacity with 2 CmA (4000 mAh) discharge at 0° C. was not sufficient. This is probably because the first lithium-nickel composite oxide surface is covered with Ni or Co having low oxidation number and electrochemical activity.
The results above were the same as the case when the surface layer portion includes element M and Ni1-δO (0≦δ≦0.1).
EXAMPLE 12
A first lithium-nickel composite oxide having a composition of Li1.03Ni0.9Co0.07Al0.03O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 90:7:3 upon synthesizing the first lithium composite oxide. Example Batteries N1 to N44 and Comparative Example Batteries n1 to n14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 14.







TABLE 14







First Lithium-Nickel Composite Oxide: Li1.03Ni0.90Co0.07Al0.03O2















Internal






Short Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be

Performance
5 mm/Sec



Allowed to Stand

Discharge
Highest

















Amount
NaCl-type Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere-
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
N1
Ta
0.5
Present
25 · 55
Oxygen-650° C.
1995
1901
74


EX.
N2

2.0



1997
1902
75


Ex.
N3
Al
0.5



1992
1910
65


Ex.
N4

2.0



1995
1901
72


Ex.
N5
Zr
0.5



1989
1904
65


Ex.
N6

2.0



1994
1904
71


Ex.
N7
Mg
0.5



1989
1902
70


Ex.
N8

2.0



1992
1905
72


Ex.
N9
In
0.5



1994
1900
68


Ex.
N10

2.0



1995
1900
69


Ex.
N11
Sn
0.5



1992
1902
68


Ex.
N12

2.0



1990
1905
70


Ex.
N13
Mn
0.5



1990
1904
70


Ex.
N14

2.0



1992
1910
69


Ex.
N15
B
0.5



1990
1905
68


Ex.
N16

2.0



1990
1902
62


Ex.
N17
W
0.5



1995
1904
68


Ex.
N18

2.0



1989
1902
69


Ex.
N19
Nb
0.5



1989
1906
66


Ex.
N20

2.0



1992
1904
65


Ex.
N21
Mo
0.5



1991
1900
68


Ex.
N22

2.0



1990
1902
69


Ex.
N23
Ta
2.5



1990
1805
67


Ex.
N24
Al




1990
1800
69


Ex.
N25
Zr




1994
1802
68


Ex.
N26
Mg




1992
1801
69


Ex.
N27
In




1991
1802
70


Ex.
N28
Sn




1992
1805
71


Ex.
N29
Mn




1995
1800
65


Ex.
N30
B




1994
1804
68


Ex.
N31
W




1988
1802
69


Ex.
N32
Nb




1989
1800
70


Ex.
N33
Mo




1982
1800
70


Ex.
N34
Ta
0.5

60 · 55

1800
1700
70


Ex.
N35
Al




1802
1701
69


Ex.
N36
Zr




1800
1705
68


Ex.
N37
Mg




1801
1704
67


Ex.
N38
In




1802
1704
68


Ex.
N39
Sn




1805
1706
70


Ex.
N40
Mn




1804
1702
69


Ex.
N41
B




1805
1704
71


Ex.
N42
W




1804
1704
69


Ex.
N43
Nb




1805
1710
68


Ex.
N44
Mo




1810
1700
67


Comp. Ex.
n1
Ta
0.5
Absent
25 · 20

1992
1912
120


Comp. Ex.
n2
Al




1990
1910
118


Comp. Ex.
n3
Zr




1990
1914
120


Comp. Ex.
n4
Mg




1995
1915
118


Comp. Ex.
n5
In




1994
1915
119


Comp. Ex.
n6
Sn




1990
1910
119


Comp. Ex.
n7
Mn




1991
1910
121


Comp. Ex.
n8
B




1989
1911
122


Comp. Ex.
n9
W




1988
1912
122


Comp. Ex.
n10
Nb




1991
1911
117


Comp. Ex.
n11
Mo




1994
1915
120


Comp. Ex.
n12
Not
—
Present
25 · 55

1720
1599
65















Comp. Ex.
n13
Added

Absent
Mixed Gas of 
2005
1901
122







Nitrogen: Hydregen = 95:5







(molar ratio)







treated at 400° C. for







6 hours


Comp. Ex.
n14



Not Carried Out
2007
1905
127









EXAMPLE 13
A first lithium-nickel composite oxide having a composition of Li1.03Ni0.25Co0.25Al0.50O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 25:25:50 upon synthesizing the first lithium-nickel composite oxide. Example Batteries O1 to O44 and Comparative Example Batteries o1 to o14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 15.







TABLE 15







First Lithium-Nickel Composite Oxide: Li1.03Ni0.25Co0.25Al0.50O2















Internal






Short Circuit






Safety






60° C.-



Environment

Discharge
Crush Speed



to be

Performance
5 mm/Sec



Allowed to Stand

Discharge
Highest

















Amount
NaCl-type Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere-
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
O1
Ta
0.5
Present
25 · 55
Oxygen-
1482
1450
64


Ex.
O2

2.0


650° C.
1488
1452
67


Ex.
O3
Al
0.5



1481
1452
62


Ex.
O4

2.0



1480
1455
64


Ex.
O5
Zr
0.5



1471
1455
62


Ex.
O6

2.0



1475
1460
66


Ex.
O7
Mg
0.5



1474
1458
69


Ex.
O8

2.0



1472
1458
68


Ex.
O9
In
0.5



1477
1457
64


Ex.
O10

2.0



1480
1458
69


Ex.
O11
Sn
0.5



1474
1455
75


Ex.
O12

2.0



1477
1450
69


Ex.
O13
Mn
0.5



1481
1456
64


Ex.
O14

2.0



1480
1452
75


Ex.
O15
B
0.5



1488
1453
66


Ex.
O16

2.0



1477
1455
68


Ex.
O17
W
0.5



1478
1455
71


Ex.
O18

2.0



1482
1458
70


Ex.
O19
Nb
0.5



1488
1455
65


Ex.
O20

2.0



1487
1458
70


Ex.
O21
Mo
0.5



1485
1455
72


Ex.
O22

2.0



1477
1459
67


Ex.
O23
Ta
2.5



1478
1350
70


Ex.
O24
Al




1485
1352
70


Ex.
O25
Zr




1488
1355
61


Ex.
O26
Mg




1482
1354
65


Ex.
O27
In




1472
1352
75


Ex.
O28
Sn




1482
1350
60


Ex.
O29
Mn




1488
1350
69


Ex.
O30
B




1488
1351
68


Ex.
O31
W




1482
1352
68


Ex.
O32
Nb




1485
1355
70


Ex.
O33
Mo




1482
1355
70


Ex.
O34
Ta
0.5

60 · 55

1355
1201
59


Ex.
O35
Al




1352
1199
62


Ex.
O36
Zr




1351
1198
70


Ex.
O37
Mg




1355
1197
66


Ex.
O38
In




1352
1199
68


Ex.
O39
Sn




1354
1197
68


Ex.
O40
Mn




1356
1200
70


Ex.
O41
B




1355
1201
70


Ex.
O42
W




1350
1205
65


Ex.
O43
Nb




1350
1202
72


Ex.
O44
Mo




1352
1200
69


Comp. Ex.
o1
Ta
0.5
Absent
25 · 20

1492
1420
115


Comp. Ex.
o2
Al




1490
1420
120


Comp. Ex.
o3
Zr




1498
1422
112


Comp. Ex.
o4
Mg




1497
1425
100


Comp. Ex.
o5
In




1485
1420
120


Comp. Ex.
o6
Sn




1477
1420
115


Comp. Ex.
o7
Mn




1488
1420
120


Comp. Ex.
o8
B




1487
1420
115


Comp. Ex.
o9
W




1496
1420
122


Comp. Ex.
o10
Nb




1479
1422
124


Comp. Ex.
o11
Mo




1477
1425
105


Comp. Ex.
o12
Not
—
Present
25 · 55

1320
1170
80















Comp. Ex.
o13
Added

Absent
Mixed Gas of
1500
1400
120







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at







400° C. for 6 hours


Comp. Ex.
o14



Not Carried Out
1500
1420
125









EXAMPLE 14
A first lithium-nickel composite oxide having a composition of Li1.03Ni0.25Cu0.50Al0.25O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 25:50:25 upon synthesizing the first lithium-nickel composite oxide. Example Batteries P1 to P44 and Comparative Example Batteries p1 to p14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 16.







TABLE 16







First Lithium-Nickel Composite Oxide: Li1.03Ni0.25Co0.50Al0.25O2

















Internal







Short Circuit







Safety







60° C.-




Environment

Discharge
Crush Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere-
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
P1
Ta
0.5
Present
25 · 55
Oxygen-650° C.
1882
1812
70


Ex.
P2

2.0



1891
1815
62


Ex.
P3
Al
0.5



1880
1810
65


Ex.
P4

2.0



1882
1815
70


Ex.
P5
Zr
0.5



1880
1812
71


Ex.
P6

2.0



1881
1810
71


Ex.
P7
Mg
0.5



1890
1812
65


Ex.
P8

2.0



1890
1815
65


Ex.
P9
In
0.5



1879
1810
71


Ex.
P10

2.0



1888
1812
70


Ex.
P11
Sn
0.5



1890
1814
61


Ex.
P12

2.0



1887
1816
70


Ex.
P13
Mn
0.5



1885
1815
65


Ex.
P14

2.0



1884
1815
65


Ex.
P15
B
0.5



1888
1815
71


Ex.
P16

2.0



1889
1810
72


Ex.
P17
W
0.5



1890
1811
64


Ex.
P18

2.0



1890
1812
68


Ex.
P19
Nb
0.5



1870
1815
62


Ex.
P20

2.0



1885
1812
62


Ex.
P21
Mo
0.5



1889
1800
72


Ex.
P22

2.0



1885
1800
72


Ex.
P23
Ta
2.5



1891
1601
70


Ex.
P24
Al




1880
1605
72


Ex.
P25
Zr




1879
1602
67


Ex.
P26
Mg




1892
1608
68


Ex.
P27
In




1891
1607
64


Ex.
P28
Sn




1889
1602
65


Ex.
P29
Mn




1895
1603
69


Ex.
P30
B




1897
1608
65


Ex.
P31
W




1889
1600
68


Ex.
P32
Nb




1890
1601
65


Ex.
P33
Mo




1890
1602
60


Ex.
P34
Ta
0.5

60 · 55

1602
1502
67


Ex.
P35
Al




1604
1500
65


Ex.
P36
Zr




1605
1504
70


Ex.
P37
Mg




1610
1501
65


Ex.
P38
In




1605
1508
65


Ex.
P39
Sn




1608
1509
70


Ex.
P40
Mn




1604
1510
64


Ex.
P41
B




1610
1511
70


Ex.
P42
W




1609
1512
68


Ex.
P43
Nb




1608
1513
70


Ex.
P44
Mo




1608
1512
72


Comp. Ex.
p1
Ta
0.5
Absent
25 · 20

1882
1810
122


Comp. Ex.
p2
Al




1884
1809
123


Comp. Ex.
p3
Zr




1880
1804
124


Comp. Ex.
p4
Mg




1891
1809
121


Comp. Ex.
p5
In




1890
1802
122


Comp. Ex.
p6
Sn




1888
1809
125


Comp. Ex.
p7
Mn




1879
1807
122


Comp. Ex.
p8
B




1880
1807
124


Comp. Ex.
p9
W




1889
1809
122


Comp. Ex.
p10
Nb




1880
1087
120


Comp. Ex.
p11
Mo




1890
1807
120


Comp. Ex.
p12
Not
—
Present
25 · 55

1608
1479
79















Comp. Ex.
p13
Added

Absent
Mixed Gas of
1890
1820
130







Nitrngen:Hydrogen = 95:5







(molar ratio)







treated at 400° C.







for 6 hours


Comp. Ex.
p14



Not Carried Out
1895
1827
132









EXAMPLE 15
A first lithium-nickel composite oxide having a composition of Li1.03Ni0.90Co0.10O2 was obtained by using nickel sulfate and cobalt sulfate without using aluminum sulfate so that a molar ratio of Ni atoms to Co atoms was 90:10 upon synthesizing the first lithium-nickel composite oxide. Example Batteries Q1 to Q44 and Comparative Example Batteries q1 to q14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 17.







TABLE 17







First Lithium-Nickel Composite Oxide: Li1.03Ni0.90Co0.10O2

















Internal







Short Circuit







Safety







60° C.-




Environment to

Discharge
Crush Speed




be Allowed to

Performance
5 mm/Sec



NaCl-type
Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere-
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
Q1
Ta
0.5
Present
25 · 55
Oxygen-650° C.
2001
1901
70


Ex.
Q2

2.0



2002
1902
75


Ex.
Q3
Al
0.5



2003
1907
62


Ex.
Q4

2.0



2004
1905
67


Ex.
Q5
Zr
0.5



2001
1901
64


Ex.
Q6

2.0



2005
1905
72


Ex.
Q7
Mg
0.5



2008
1907
62


Ex.
Q8

2.0



2007
1901
67


Ex.
Q9
In
0.5



2000
1900
68


Ex.
Q10

2.0



2001
1902
62


Ex.
Q11
Sn
0.5



2006
1908
62


Ex.
Q12

2.0



2007
1908
60


Ex.
Q13
Mn
0.5



2009
1901
62


Ex.
Q14

2.0



2005
1904
65


Ex.
Q15
B
0.5



2004
1903
70


Ex.
Q16

2.0



2000
1905
60


Ex.
Q17
W
0.5



2003
1908
68


Ex.
Q18

2.0



2000
1907
65


Ex.
Q19
Nb
0.5



2004
1902
62


Ex.
Q20

2.0



2005
1900
65


Ex.
Q21
Mo
0.5



2002
1901
67


Ex.
Q22

2.0



2004
1908
65


Ex.
Q23
Ta
2.5



2002
1701
70


Ex.
Q24
Al




2004
1701
70


Ex.
Q25
Zr




2001
1705
65


Ex.
Q26
Mg




2000
1706
70


Ex.
Q27
In




2004
1707
67


Ex.
Q28
Sn




2003
1701
65


Ex.
Q29
Mn




2002
1704
71


Ex.
Q30
B




2002
1707
68


Ex.
Q31
W




2004
1700
65


Ex.
Q32
Nb




2001
1705
71


Ex.
Q33
Mo




2003
1704
65


Ex.
Q34
Ta
0.5

60 · 55

1750
1611
60


Ex.
Q35
Al




1740
1613
72


Ex.
Q36
Zr




1747
1609
75


Ex.
Q37
Mg




1757
1619
62


Ex.
Q38
In




1758
1620
70


Ex.
Q39
Sn




1760
1627
62


Ex.
Q40
Mn




1747
1622
67


Ex.
Q41
B




1749
1619
68


Ex.
Q42
W




1752
1617
69


Ex.
Q43
Nb




1755
1617
64


Ex.
Q44
Mo




1754
1627
64


Comp. Ex.
q1
Ta
0.5
Absent
25 · 20

2003
1901
117


Comp. Ex.
q2
Al




2005
1902
117


Comp. Ex.
q3
Zr




2004
1909
119


Comp. Ex.
q4
Mg




2005
1904
117


Comp. Ex.
q5
In




2000
1902
115


Comp. Ex.
q6
Sn




2003
1907
114


Comp. Ex.
q7
Mn




2005
1903
119


Comp. Ex.
q8
B




2002
1901
119


Comp. Ex.
q9
W




2004
1900
118


Comp. Ex.
q10
Nb




2003
1904
118


Comp. Ex.
q11
Mo




2007
1900
118


Comp. Ex.
q12
Not
—
Present
25 · 55

1760
1611
70















Comp. Ex.
q13
Added

Absent
Mixed Gas of
2008
1910
112







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C. for 6 hours


Comp. Ex.
q14



Not Carried Out
2007
1919
122









EXAMPLE 16
A first lithium-nickel composite oxide having a composition of Li1.03Ni0.50Co0.50O2 was obtained by using nickel sulfate and cobalt sulfate without using aluminum sulfate so that a molar ratio of Ni atoms to Co atoms was 50:50 upon synthesizing the first lithium-nickel composite oxide. Example Batteries R1 to R44 and Comparative Example Batteries r1 to r14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 18.







TABLE 18







First Lithium-Nickel Composite Oxide: Li1.03Ni0.50Co0.50O2

















Internal







Short







Circuit







Safety







60° C.-




Environment to

Discharge
Crush Speed




be Allowed to

Performance
5 mm/Sec




Stand

Discharge
Highest

















Amount
NaCl-type Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere-
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
R1
Ta
0.5
Present
25 · 55
Oxygen-
2001
1901
64


Ex.
R2

2.0


650° C.
2002
1903
68


Ex.
R3
Al
05



2003
1902
65


Ex.
R4

2.0



2002
1900
62


Ex.
R5
Zr
0.5



2004
1904
61


Ex.
R6

2.0



2005
1905
67


Ex.
R7
Mg
0.5



2000
1902
65


Ex.
R8

2.0



2000
1907
65


Ex.
R9
In
0.5



2001
1908
61


Ex.
R10

2.0



2001
1907
62


Ex.
R11
Sn
0.5



2002
1905
62


Ex.
R12

2.0



2004
1906
66


Ex.
R13
Mn
0.5



2003
1907
66


Ex.
R14

2.0



2005
1905
65


Ex.
R15
B
0.5



2001
1906
70


Ex.
R16

2.0



2000
1907
64


Ex.
R17
W
0.5



2001
1907
66


Ex.
R18

2.0



2004
1917
62


Ex.
R19
Nb
0.5



2005
1907
64


Ex.
R20

2.0



2006
1905
64


Ex.
R21
Mo
0.5



2003
1907
67


Ex.
R22

2.0



2001
1900
60


Ex.
R23
Ta
2.5



2004
1701
65


Ex.
R24
Al




2001
1702
64


Ex.
R25
Zr




2000
1708
65


Ex.
R26
Mg




2002
1709
65


Ex.
R27
In




2000
1706
65


Ex.
R28
Sn




2001
1704
65


Ex.
R29
Mn




2003
1702
62


Ex.
R30
B




2004
1700
65


Ex.
R31
W




2002
1703
63


Ex.
R32
Nb




2001
1702
66


Ex.
R33
Mo




2005
1708
65


Ex.
R34
Ta
0.5

60 · 55

1770
1637
62


Ex.
R35
Al




1777
1647
65


Ex.
R36
Zr




1780
1644
62


Ex.
R37
Mg




1782
1650
65


Ex.
R38
In




1772
1638
67


Ex.
R39
Sn




1773
1637
68


Ex.
R40
Mn




1774
1657
65


Ex.
R41
B




1773
1652
65


Ex.
R42
W




1772
1650
64


Ex.
R43
Nb




1777
1677
61


Ex.
R44
Mo




1771
1667
69


Comp. Ex.
r1
Ta
0.5
Absent
25 · 20

2002
1902
119


Comp. Ex.
r2
Al




2000
1900
111


Comp. Ex.
r3
Zr




2003
1905
110


Comp. Ex.
r4
Mg




2001
1905
113


Comp. Ex.
r5
In




2000
1900
116


Comp. Ex.
r6
Sn




2001
1906
115


Comp. Ex.
r7
Mn




2002
1907
110


Comp. Ex.
r8
B




2006
1901
119


Comp. Ex.
r9
W




2008
1903
121


Comp. Ex.
r10
Nb




2007
1907
122


Comp. Ex.
r11
Mo




2005
1900
111


Comp. Ex.
r12
Not
—
Present
25 · 55

1711
1655
65















Comp. Ex.
r13
Added

Absent
Mixed Gas of
2009
1920
130







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C. for 6 hours


Comp. Ex.
r14



Not Carried Out
2010
1927
137









EXAMPLE 17
Nickel sulfate, cobalt sulfate, and aluminum sulfate were mixed so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 80:15:3. The obtained mixture in an amount of 3.2 kg was dissolved in 10 L of water, to obtain a raw material solution. To the raw material solution, 400 g of sodium hydroxide was added to form a precipitate. The precipitate was sufficiently washed with water and dried, to obtain a coprecipitated hydroxide.
To 3 kg of the obtained coprecipitated hydroxide of Ni—Co—Al, 870 g of lithium hydroxide and 378 g of manganese nitrate were mixed. The obtained mixture was baked under an atmosphere with an oxygen partial pressure of 0.5 atm at a synthesizing temperature of 750° C. for 10 hours, to obtain a first lithium-nickel composite oxide including excessive lithium (composition: Li1.03Ni0.8Co0.15Al0.03Mn0.02O2).
Example Batteries S1 to S44 and Comparative Example Batteries s1 to s14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that the lithium composite oxide was used as a raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 19.







TABLE 19







First Lithium-Nickel Composite Oxide: Li1.03Ni0.80Co0.15Al0.03Mn0.02O2

















Internal







Short







Circuit







Safety







60° C. - Crush




Environment

Discharge
Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere ·
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
S1
Ta
0.5
Present
25 · 55
Oxygen-
2004
1902
66


Ex.
S2

2.0


650° C.
2005
1900
67


Ex.
S3
Al
0.5



2004
1904
65


Ex.
S4

2.0



2005
1907
60


Ex.
S5
Zr
0.5



2002
1905
65


Ex.
S6

2.0



2005
1902
62


Ex.
S7
Mg
0.5



2008
1904
60


Ex.
S8

2.0



2009
1907
64


Ex.
S9
In
0.5



2007
1907
65


Ex.
S10

2.0



2007
1901
61


Ex.
S11
Sn
0.5



2006
1905
65


Ex.
S12

2.0



2004
1907
65


Ex.
S13
Mn
0.5



2005
1901
64


Ex.
S14

2.0



2004
1900
64


Ex.
S15
B
0.5



2005
1905
64


Ex.
S16

2.0



2003
1907
67


Ex.
S17
W
0.5



2002
1908
66


Ex.
S18

2.0



2005
1909
60


Ex.
S19
Nb
0.5



2002
1910
61


Ex.
S20

2.0



2000
1901
67


Ex.
S21
Mo
0.5



2005
1912
68


Ex.
S22

2.0



2005
1900
65


Ex.
S23
Ta
2.5



2004
1711
62


Ex.
S24
Al




2000
1720
60


Ex.
S25
Zr




2001
1727
62


Ex.
S26
Mg




2002
1722
68


Ex.
S27
In




2002
1715
68


Ex.
S28
Sn




2008
1720
64


Ex.
S29
Mn




2002
1710
66


Ex.
S30
B




2002
1715
64


Ex.
S31
W




2000
1726
60


Ex.
S32
Nb




2005
1717
64


Ex.
S33
Mo




2004
1709
66


Ex.
S34
Ta
0.5

60 · 55

1755
1667
68


Ex.
S35
Al




1757
1670
66


Ex.
S36
Zr




1767
1671
65


Ex.
S37
Mg




1754
1669
62


Ex.
S38
In




1752
1670
62


Ex.
S39
Sn




1747
1657
64


Ex.
S40
Mn




1767
1671
65


Ex.
S41
B




1765
1682
65


Ex.
S42
W




1774
1682
65


Ex.
S43
Nb




1777
1677
62


Ex.
S44
Mo




1787
1680
66


Comp. Ex.
s1
Ta
0.5
Absent
25 · 20

2001
1907
122


Comp. Ex.
s2
Al




2003
1910
120


Comp. Ex.
s3
Zr




2002
1911
121


Comp. Ex.
s4
Mg




2005
1912
118


Comp. Ex.
s5
In




2001
1908
119


Comp. Ex.
s6
Sn




2003
1909
117


Comp. Ex.
s7
Mn




2005
1907
119


Comp. Ex.
s8
B




2007
1910
121


Comp. Ex.
s9
W




2002
1911
119


Comp. Ex.
s10
Nb




2003
1908
120


Comp. Ex.
s11
Mo




2005
1907
118


Comp. Ex.
s12
Not
—
Present
25 · 55

1734
1620
66















Comp. Ex.
s13
Added

Absent
Mixed Gas of
2009
1919
122







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C. for 6 hours


Comp. Ex.
s14



Not Carried Out
2010
1927
132









EXAMPLE 18
To 3 kg of a coprecipitated hydroxide of Ni—Co—Al prepared in the same manner as Example 17, 870 g of lithium hydroxide and 378 g of magnesium sulfate were mixed. The obtained mixture was baked under an atmosphere with an oxygen partial pressure of 0.5 atm at a synthesizing temperature of 750° C. for 10 hours, to obtain a first lithium-nickel composite oxide including excessive lithium (composition: Li1.03Ni0.8Co0.15Al0.03Mg0.02O2).
Example Batteries T1 to T44 and Comparative Example Batteries t1 to t14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this lithium composite oxide was used as a raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 20.







TABLE 20







First Lithium-Nickel Composite Oxide: Li1.03Ni0.80Co0.15Al0.03Mg0.02O2

















Internal







Short







Circuit







Safety







60° C. - Crush




Environment

Discharge
Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere ·
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
T1
Ta
0.5
Present
25 · 55
Oxygen ·
2002
1902
64


Ex.
T2

2.0


650° C.
2004
1900
60


Ex.
T3
Al
0.5



2005
1902
66


Ex.
T4

2.0



2002
1903
63


Ex.
T5
Zr
0.5



2001
1904
62


Ex.
T6

2.0



2000
1901
64


Ex.
T7
Mg
0.5



2005
1902
62


Ex.
T8

2.0



2002
1901
67


Ex.
T9
In
0.5



2000
1907
62


Ex.
T10

2.0



2005
1905
69


Ex.
T11
Sn
0.5



2001
1900
62


Ex.
T12

2.0



2002
1900
61


Ex.
T13
Mn
0.5



2000
1902
63


Ex.
T14

2.0



2004
1902
62


Ex.
T15
B
0.5



2004
1905
65


Ex.
T16

2.0



2005
1905
66


Ex.
T17
W
0.5



2002
1900
67


Ex.
T18

2.0



2000
1900
64


Ex.
T19
Nb
0.5



2004
1900
65


Ex.
T20

2.0



2005
1901
64


Ex.
T21
Mo
0.5



2007
1902
62


Ex.
T22

2.0



2003
1902
67


Ex.
T23
Ta
2.5



2005
1702
62


Ex.
T24
Al




2003
1700
67


Ex.
T25
Zr




2004
1705
63


Ex.
T26
Mg




2005
1703
64


Ex.
T27
In




2008
1704
64


Ex.
T28
Sn




2009
1705
67


Ex.
T29
Mn




2007
1705
63


Ex.
T30
B




2007
1707
66


Ex.
T31
W




2007
1707
68


Ex.
T32
Nb




2006
1700
62


Ex.
T33
Mo




2005
1700
62


Ex.
T34
Ta
0.5

60 · 55

1782
1611
62


Ex.
T35
Al




1777
1614
60


Ex.
T36
Zr




1779
1626
61


Ex.
T37
Mg




1781
1627
64


Ex.
T38
In




1782
1634
62


Ex.
T39
Sn




1783
1626
65


Ex.
T40
Mn




1787
1620
64


Ex.
T41
B




1771
1630
65


Ex.
T42
W




1773
1643
63


Ex.
T43
Nb




1772
1625
61


Ex.
T44
Mo




1777
1632
64


Comp. Ex.
t1
Ta
0.5
Absent
25 · 20

2001
1907
120


Comp. Ex.
t2
Al




2004
1903
121


Comp. Ex.
t3
Zr




2003
1906
120


Comp. Ex.
t4
Mg




2004
1909
119


Comp. Ex.
t5
In




2005
1900
124


Comp. Ex.
t6
Sn




2001
1901
125


Comp. Ex.
t7
Mn




2002
1902
130


Comp. Ex.
t8
B




2001
1901
128


Comp. Ex.
t9
W




2002
1907
122


Comp. Ex.
t10
Nb




2000
1904
129


Comp. Ex.
t11
Mo




2005
1905
125


Comp. Ex.
t12
Not
—
Present
25 · 55

1722
1602
69















Comp. Ex.
t13
Added

Absent
Mixed Gas of
2007
1907
132







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C. for 6 hours


Comp. Ex.
t14



Not Carried Out
2009
1917
135









EXAMPLE 19
To 3 kg of a coprecipitated hydroxide of Ni—Co—Al prepared in the same manner as Example 17, 870 g of lithium hydroxide and 378 g of calcium hydroxide were mixed. The obtained mixture was baked under an atmosphere with an oxygen partial pressure of 0.5 atm at a synthesizing temperature of 750° C. for 10 hours, to obtain a first lithium-nickel composite oxide including excessive lithium (composition: Li1.03Ni0.8Co0.15Al0.03Ca0.02O2).
Example Batteries U1 to U44 and Comparative Example Batteries u1 to u35 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this lithium composite oxide was used as a raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 21.







TABLE 21







First Lithium-Nickel Composite Oxide: Li1.03Ni0.80Co0.15Al0.03Ca0.02O2

















Internal







Short







Circuit







Safety







60° C. - Crush




Environment

Discharge
Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere ·
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
U1
Ta
0.5
Present
25 · 25
Oxygen ·
2002
1912
65


Ex.
U2

2.0


650° C.
2004
1911
62


Ex.
U3
Al
0.5



2005
1910
65


Ex.
U4

2.0



2004
1913
65


Ex.
U5
Zr
0.5



2002
1914
64


Ex.
U6

2.0



2005
1914
64


Ex.
U7
Mg
0.5



2006
1915
62


Ex.
U8

2.0



2004
1911
68


Ex.
U9
In
0.5



2005
1908
69


Ex.
U10

2.0



2002
1909
65


Ex.
U11
Sn
0.5



2004
1912
60


Ex.
U12

2.0



2005
1914
66


Ex.
U13
Mn
0.5



2006
1917
67


Ex.
U14

2.0



2007
1908
62


Ex.
U15
B
0.5



2004
1915
62


Ex.
U16

2.0



2002
1917
62


Ex.
U17
W
0.5



2006
1911
68


Ex.
U18

2.0



2004
1911
64


Ex.
U19
Nb
0.5



2003
1914
64


Ex.
U20

2.0



2002
1912
68


Ex.
U21
Mo
0.5



2001
1913
67


Ex.
U22

2.0



2005
1917
64


Ex.
U23
Ta
2.5



2004
1712
64


Ex.
U24
Al




2000
1712
61


Ex.
U25
Zr




2002
1709
68


Ex.
U26
Mg




2005
1710
62


Ex.
U27
In




2004
1717
65


Ex.
U28
Sn




2003
1703
62


Ex.
U29
Mn




2005
1704
62


Ex.
U30
B




2000
1707
68


Ex.
U31
W




2002
1717
68


Ex.
U32
Nb




2005
1710
67


Ex.
U33
Mo




2007
1717
64


Ex.
U34
Ta
0.5

60 · 55

1774
1660
67


Ex.
U35
Al




1779
1664
64


Ex.
U36
Zr




1757
1670
64


Ex.
U37
Mg




1767
1672
67


Ex.
U38
In




1771
1667
62


Ex.
U39
Sn




1764
1669
62


Ex.
U40
Mn




1757
1672
68


Ex.
U41
B




1770
1680
64


Ex.
U42
W




1761
1672
64


Ex.
U43
Nb




1775
1682
65


Ex.
U44
Mo




1770
1682
68


Comp.
u1
Ta
0.5
Absent
25 · 20

2003
1907
120


Comp.
u2
Al




2007
1902
119


Comp.
u3
Zr




2005
1903
117


Comp.
u4
Mg




2008
1907
122


Comp.
u5
In




2002
1909
120


Comp.
u6
Sn




2004
1902
117


Comp.
u7
Mn




2007
1904
117


Comp.
u8
B




2003
1907
121


Comp.
u9
W




2005
1903
119


Comp.
u10
Nb




2002
1907
124


Comp.
u11
Mo




2000
1902
127


Comp.
u12
Not
—
Present
25 · 55

1727
1600
69















Comp.
u13
Added

Absent
Mixed Gas of
2004
1920
119







Nitrogen:Hydroge = 95:5







(molar ratio)







treated at 400° C. for 6 hours


Comp.
u14



Not Carried Out
2007
1914
120









EXAMPLE 20
To 3 kg of the coprecipitated hydroxide of Ni—Co—Al prepared in the same manner as Example 17, 870 g of lithium hydroxide and 378 g of titanium sulfate were mixed. The obtained mixture was baked under an atmosphere with an oxygen partial pressure of 0.5 atm at a synthesizing temperature of 750° C. for 10 hours, to obtain a first lithium-nickel composite oxide including excessive lithium (composition: Li1.03Ni0.8Co0.15Al0.03Ti0.02O2).
Example Batteries V1 to V44 and Comparative Example Batteries v1 to v14 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this lithium composite oxide was used for a raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 22.







TABLE 22







First Lithium-Nickel Composite Oxide: Li1.03Ni0.80Co0.15Al0.03Ti0.02O2

















Internal







Short







Circuit







Safety







60° C. - Crush




Environment

Discharge
Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere ·
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Ex.
V1
Ta
0.5
Present
25 · 55
Oxygen ·
2002
1902
64


Ex.
V2

2.0


650° C.
2002
1900
65


Ex.
V3
Al
0.5



2005
1905
67


Ex.
V4

2.0



2000
1902
65


Ex.
V5
Zr
0.5



2002
1900
64


Ex.
V6

2.0



2002
1905
65


Ex.
V7
Mg
0.5



2000
1900
68


Ex.
V8

2.0



2000
1902
62


Ex.
V9
In
0.5



2003
1903
68


Ex.
V10

2.0



2004
1903
63


Ex.
V11
Sn
0.5



2004
1900
60


Ex.
V12

2.0



2002
1903
60


Ex.
V13
Mn
0.5



2003
1902
64


Ex.
V14

2.0



2003
1905
64


Ex.
V15
B
0.5



2005
1903
64


Ex.
V16

2.0



2001
1902
61


Ex.
V17
W
0.5



2004
1904
62


Ex.
V18

2.0



2005
1904
65


Ex.
V19
Nb
0.5



2002
1902
68


Ex.
V20

2.0



2002
1904
64


Ex.
V21
Mo
0.5



2000
1904
68


Ex.
V22

2.0



2004
1900
66


Ex.
V23
Ta
2.5



2006
1707
60


Ex.
V24
Al




2002
1708
62


Ex.
V25
Zr




2002
1700
60


Ex.
V26
Mg




2003
1704
62


Ex.
V27
In




2000
1704
67


Ex.
V28
Sn




2006
1707
62


Ex.
V29
Mn




2005
1700
62


Ex.
V30
B




2002
1710
68


Ex.
V31
W




2000
1702
68


Ex.
V32
Nb




2006
1700
64


Ex.
V33
Mo




2004
1711
64


Ex.
V34
Ta
0.5

60 · 55

1175
1627
62


Ex.
V35
Al




1777
1622
61


Ex.
V36
Zr




1776
1624
65


Ex.
V37
Mg




1775
1637
64


Ex.
V38
In




1772
1635
60


Ex.
V39
Sn




1771
1627
62


Ex.
V40
Mn




1772
1647
67


Ex.
V41
B




1775
1640
63


Ex.
V42
W




1782
1627
62


Ex.
V43
Nb




1779
1647
64


Ex.
V44
Mo




1778
1617
62


Comp. Ex.
v1
Ta
0.5
Absent
25 · 20

2007
1905
119


Comp. Ex.
v2
Al




2005
1907
120


Comp. Ex.
v3
Zr




2008
1908
124


Comp. Ex.
v4
Mg




2004
1902
123


Comp. Ex.
v5
In




2008
1907
125


Comp. Ex.
v6
Sn




2002
1904
127


Comp. Ex.
v7
Mn




2005
1905
121


Comp. Ex.
v8
B




2007
1907
127


Comp. Ex.
v9
W




2004
1904
124


Comp. Ex.
v10
Nb




2002
1907
127


Comp. Ex.
v11
Mo




2001
1904
120


Comp. Ex.
v12
Not
—
Present
25 · 55

1720
1609
71















Comp. Ex.
v13
Added

Absent
Mixed Gas of
2009
1912
125







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C. for 6 hours


Comp. Ex.
v14



Not Carried Out
2010
1920
127









The results in Tables 14 to 22 showed similar tendency with the case in Example 11.
COMPARATIVE EXAMPLE 3
A first lithium-nickel composite oxide having a composition of Li1.03Ni0.20Co0.50Al0.30O2 was obtained by using nickel sulfate, cobalt sulfate, and aluminum sulfate so that a molar ratio of Ni atoms, Co atoms, and Al atoms was 20:50:30 upon synthesizing the lithium composite oxide. Comparative Example Batteries w1 to w58 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that this first lithium-nickel composite oxide was used as the raw material for the active material particles, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 23.







TABLE 23







First Lithium-Nickel Composite Oxide: Li1.03Ni0.20Co0.50Al0.30O2

















Internal







Short







Circuit







Safety







60° C. - Crush




Environment

Discharge
Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere ·
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Comp.
w1
Ta
0.5
Present
25 · 55
Oxygen ·
1810
1710
117


Comp.
w2

2.0


650° C.
1815
1710
118


Comp.
w3
Al
0.5



1805
1715
115


Comp.
w4

2.0



1810
1709
100


Comp.
w5
Zr
0.5



1800
1710
120


Comp.
w6

2.0



1802
1710
110


Comp.
w7
Mg
0.5



1807
1715
106


Comp.
w8

2.0



1804
1712
112


Comp.
w9
In
0.5



1810
1715
110


Comp.
w10

2.0



1800
1705
110


Comp.
w11
Sn
0.5



1805
1715
100


Comp.
w12

2.0



1810
1710
115


Comp.
w13
Mn
0.5



1806
1712
120


Comp.
w14

2.0



1810
1720
100


Comp.
w15
B
0.5



1805
1708
115


Comp.
w16

2.0



1802
1710
118


Comp.
w17
W
0.5



1804
1715
117


Comp.
w18

2.0



1805
1700
120


Comp.
w19
Nb
0.5



1800
1712
120


Comp.
w20

2.0



1805
1715
115


Comp.
w21
Mo
0.5



1805
1715
115


Comp.
w22

2.0



1805
1710
116


Comp.
w23
Ta
2.5



1789
1530
125


Comp.
w24
Al




1788
1535
115


Comp.
w25
Zr




1785
1540
120


Comp.
w26
Mg




1779
1530
120


Comp.
w27
In




1783
1540
118


Comp.
w28
Sn




1785
1530
110


Comp.
w29
Mn




1788
1532
115


Comp.
w30
B




1782
1535
117


Comp.
w31
W




1779
1530
115


Comp.
w32
Nb




1780
1530
112


Comp.
w33
Mo




1790
1533
110


Comp.
w34
Ta
0.5

60 · 55

1770
1622
105


Comp.
w35
Al




1769
1623
120


Comp.
w36
Zr




1763
1627
117


Comp.
w36
Mg




1767
1622
116


Comp.
w38
In




1757
1616
110


Comp.
w39
Sn




1760
1627
120


Comp.
w40
Mn




1762
1620
118


Comp.
w41
B




1767
1618
110


Comp.
w42
W




1770
1610
120


Comp.
w43
Nb




1758
1610
113


Comp.
w44
Mo




1759
1612
105


Comp.
w45
Ta
0.5
Absent
25 · 20

1805
1709
120


Comp.
w46
Al




1805
1715
120


Comp.
w47
Zr




1805
1710
118


Comp.
w48
Mg




1805
1710
117


Comp.
w49
In




1802
1710
115


Comp.
w50
Sn




1801
1712
105


Comp.
w51
Mn




1806
1715
117


Comp.
w52
B




1802
1715
117


Comp.
w53
W




1800
1710
119


Comp.
w54
Nb




1805
1715
112


Comp.
w55
Mo




1800
1705
122


Comp.
w56
Not
—
Present
25 · 55

1760
1601
112















Comp.
w57
Added

Absent
Mixed Gas of
1803
1712
135







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C.







for 6 hours


Comp.
w58



Not Carried Out
1800
1720
138









No presence of the domain having the NaCl-type crystal structure was confirmed upon analysis of the active material particles of Comparative Example Batteries w1 to w58. The results of Tables 23A and 23B made clear that a large heat generation is caused in the crush test in the case when y+z exceeds 0.75 in the first lithium-nickel composite oxide represented by the general formula LixNi1-y-zCoyMezO2, not producing the domain having the NaCl-type crystal structure.
COMPARATIVE EXAMPLE 4
Comparative Example Batteries x1 to x58 were made in the same manner as Example Batteries M1 to M44 and Comparative Example Batteries m1 to m14, respectively, except that Li1.03NiO2 was used as a raw material for the active material particles instead of the first lithium-nickel composite oxide, and the evaluation was carried out in the same manner as Example 1. The results are shown in Table 24.







TABLE 24







First Lithium-Nickel Composite Oxide: Li1.03NiO2

















Internal







Short







Circuit







Safety







60° C. - Crush




Environment

Discharge
Speed




to be Allowed

Performance
5 mm/Sec



NaCl-type
to Stand

Discharge
Highest

















Amount
Crystal
Temperature ·
Baking
400 mA
4000 mA
Temperature


Battery

Added
Structure
Humidity
Atmosphere ·
at 0° C.
at 0° C.
Reached


No
Element M
(mol %)
Domain
(° C. · %)
Temperature
(mAh)
(mAh)
(° C.)



















Comp. Ex.
x1
Ta
0.5
Present
25 · 55
Oxygen ·
2002
1810
112


Comp. Ex.
x2

2.0


650° C.
2004
1811
115


Comp. Ex.
x3
Al
0.5



2007
1822
105


Comp. Ex.
x4

2.0



2009
1820
117


Comp. Ex.
x5
Zr
0.5



2007
1828
117


Comp. Ex.
x6

2.0



2005
1819
106


Comp. Ex.
x7
Mg
0.5



2004
1811
110


Comp. Ex.
x8

2.0



2005
1813
120


Comp. Ex.
x9
In
0.5



2008
1810
116


Comp. Ex.
x10

2.0



2009
1813
120


Comp. Ex.
x11
Sn
0.5



2010
1818
110


Comp. Ex.
x12

2.0



2007
1812
115


Comp. Ex.
x13
Mn
0.5



2004
1820
117


Comp. Ex.
x14

2.0



2005
1822
110


Comp. Ex.
x15
B
0.5



2003
1824
115


Comp. Ex.
x16

2.0



2002
1825
117


Comp. Ex.
x17
W
0.5



2008
1822
119


Comp. Ex.
x18

2.0



2008
1820
116


Comp. Ex.
x19
Nb
0.5



2009
1821
122


Comp. Ex.
x20

2.0



2010
1822
100


Comp. Ex.
x21
Mo
0.5



2007
1824
112


Comp. Ex.
x22

2.0



2009
1822
110


Comp. Ex.
x23
Ta
2.5



1990
1720
118


Comp. Ex.
x24
Al




1992
1721
112


Comp. Ex.
x25
Zr




1991
1710
117


Comp. Ex.
x26
Mg




1993
1712
120


Comp. Ex.
x27
In




1992
1719
118


Comp. Ex.
x28
Sn




1990
1711
115


Comp. Ex.
x29
Mn




1992
1712
105


Comp. Ex.
x30
B




1992
1710
110


Comp. Ex.
x31
W




1990
1720
117


Comp. Ex.
x32
Nb




1991
1721
118


Comp. Ex.
x33
Mo




1990
1710
120


Comp. Ex.
x34
Ta
0.5

60 · 55

1800
1621
115


Comp. Ex.
x35
Al




1801
1618
110


Comp. Ex.
x36
Zr




1802
1611
112


Comp. Ex.
x37
Mg




1804
1610
125


Comp. Ex.
x38
In




1805
1612
115


Comp. Ex.
x39
Sn




1802
1600
105


Comp. Ex.
x40
Mn




1807
1609
120


Comp. Ex.
x41
B




1803
1608
120


Comp. Ex.
x42
W




1804
1610
100


Comp. Ex.
x43
Nb




1802
1620
120


Comp. Ex.
x44
Mo




1801
1618
110


Comp. Ex.
x45
Ta
0.5
Absent
25 · 20

2000
1810
120


Comp. Ex.
x46
Al




2001
1809
120


Comp. Ex.
x47
Zr




2000
1802
100


Comp. Ex.
x48
Mg




2000
1809
118


Comp. Ex.
x49
In




2002
1810
117


Comp. Ex.
x50
Sn




2000
1812
113


Comp. Ex.
x51
Mn




1999
1809
120


Comp. Ex.
x52
B




1998
1800
120


Comp. Ex.
x53
W




2000
1803
115


Comp. Ex.
x54
Nb




2001
1801
115


Comp. Ex.
x55
Mo




2002
1812
118


Comp. Ex.
x56
Not
—
Present
25 · 55

1990
1700
115















Comp. Ex.
x57
Added

Absent
Mixed Gas of
2010
1820
140







Nitrogen:Hydrogen = 95:5







(molar ratio)







treated at 400° C.







for 6 hours


Comp. Ex.
x58



Not Carried Out
2009
1819
142









The results of Table 24 made clear that when Li1.03NiO2 was used, though the domain having the NaCl-type crystal structure was produced, the discharge capacity was small. With an excessive presence of Li as well, when Z is greater than 0.5 in LixNi1-y-zCoyMexO2, a homogeneous solid solution could not be obtained.
INDUSTRIAL APPLICABILITY
The present invention is useful in a lithium ion secondary battery including a lithium-nickel composite oxide composed mainly of nickel as the positive electrode active material. Based on the present invention, safety upon internal short-circuit can be further improved without hindering high-rate performance at low temperature.
Form of a lithium ion secondary battery of the present invention is not particularly limited, and may be any of for example coin-type, button-type, sheet-type, cylindrical type, flat-type, and prismatic-type. Also, form of an electrode assembly including a positive electrode, a negative electrode, and a separator may be wound-type or stack-type. The size of the battery may be a small size for a small mobile devices, or may be a large size for electric vehicles. Thus, a lithium ion secondary battery of the present invention may be used as a power source for, for example, personal data assistants, mobile electronic devices, household small electric power storage devices, motorcycles, Electric Vehicles, and Hybrid Electric Vehicles. However, application is not particularly limited.

## Claims

1. A lithium ion secondary battery comprising a positive electrode capable of charging and discharging, a negative electrode capable of charging and discharging, and a non-aqueous electrolyte;
said positive electrode including active material particles;
said active material particles including at least a first lithium-nickel composite oxide forming a core portion thereof;
said first lithium-nickel composite oxide being represented by LixNi1-y-zCoyMexO2 
where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca;
a surface layer portion of said active material particles including:
(i) at least one selected from the group consisting of a nickel oxide having a NaCl crystal structure and a second lithium-nickel composite oxide including a domain having the NaCl crystal structure; and
(ii) element M not incorporated in the crystal structure of said first lithium-nickel composite oxide, said element M being at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn.

2. The lithium ion secondary battery in accordance with claim 1,
wherein said nickel oxide having the NaCl crystal structure is at least one selected from the group consisting of NiO and cation-deficient Ni1-δO, and
said domain having the NaCl crystal structure has a structure in which Li in Li site in said first lithium-nickel composite oxide is replaced with Ni, Co, or Me.

3. The lithium ion secondary battery in accordance with claim 1, wherein element M is distributed more at the outer side of said surface layer portion compared with the inner side thereof, and said nickel oxide is distributed more at the inner side of said surface layer portion compared with the outer side.

4. The lithium ion secondary battery in accordance with claim 1, wherein 0<z≦0.5, and the concentration of element Me is high in the proximity of said surface layer portion compared with the inner portion of said active material particles.

5. The lithium ion secondary battery in accordance with claim 1, wherein the amount of element M is 2 mol % or less relative to said first lithium-nickel composite oxide.

6. A method for producing a lithium ion secondary battery, the method comprising the steps of:
obtaining a positive electrode capable of charging and discharging;
obtaining a negative electrode capable of charging and discharging; and
assembling a battery including said positive electrode, said negative electrode, and a non-aqueous electrolyte:
said step of obtaining said positive electrode including the steps of:
(i) allowing a first lithium-nickel composite oxide represented by LixNi1-y-zCoyMexO2 

where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca, to carry element M of at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn;
(ii) producing NiOOH on a surface of said first lithium-nickel composite oxide by moisture in the atmosphere by allowing said first lithium-nickel composite oxide carrying element M to stand under an environment with a temperature of 60° C. or less and a humidity of 20% or more;
(iii) preliminary baking said first lithium-nickel composite oxide with NiOOH produced on the surface thereof in a dry air atmosphere, and then carrying out a main baking in an oxygen atmosphere, thereby converting said NiOOH into at least one selected from the group consisting of NiO having a NaCl crystal structure, cation-deficient Ni1-δO having the NaCl-type crystal structure, and a second lithium-nickel composite oxide including a domain having the NaCl crystal structure, to obtain active material particles; and
(iv) forming a positive electrode including said active material particles.