Source: https://patents.google.com/patent/EP2565886A1/en
Timestamp: 2018-11-14 02:51:00
Document Index: 207808177

Matched Legal Cases: ['§ 119', 'Application No. 2004', 'Application No. 2004', 'Application No. 2004', 'Application No. 2004', 'Application No. 2005']

EP2565886A1 - Material for electrolytic solution, ionic material-containing composition and use thereof - Google Patents
EP2565886A1
EP2565886A1 EP20120194162 EP12194162A EP2565886A1 EP 2565886 A1 EP2565886 A1 EP 2565886A1 EP 20120194162 EP20120194162 EP 20120194162 EP 12194162 A EP12194162 A EP 12194162A EP 2565886 A1 EP2565886 A1 EP 2565886A1
EP20120194162
The material for an electrolytic solution is the material containing an ionic compound, and the material comprises a cyano group-containing anion represented by the formula (1) ; , and 1 to 99% by mass of a solvent in 100% by mass of the material for an electrolytic solution.
Currently used as such ionic conductor are electrolytic solutions prepared by dissolving an electrolyte, such as lithium perchlorate, LiPF6, LiBF4, tetraethylammonium fluoroborate or tetramethylammonium phthalate, in an organic solvent such as γ-butyrolactone,N,N-dimethylformamide,propylene carbonate or tetrahydrofuran. In such ionic conductors, the electrolyte, when dissolved, dissociates into a cation and an anion to cause ionic conduction through the electrolytic solution.
The form of a typical lithium (ion) secondary battery is schematically shown, in cross section, in Fig. 1. Such a lithium (ion) secondary battery has a positive electrode and a negative electrode each formed of a respective active substance, and an electrolytic solution constituted of an organic solvent and a lithium salt, such as LiPF6, dissolved as a solute in the solvent forms an ionic conductor between the positive and negative electrodes. In that case, during charging, the reaction C6Li → 6C + Li + e occurs on the negative electrode, the electron (e) generated on the negative electrode surface migrates through the electrolytic solution to the positive electrode surface in the manner of ionic conduction. On the positive electrode surface, the reaction CoO2 + Li + e → LiCoO2 occurs and an electric current flows from the negative to the positive electrode. During discharging, reverse reactions as compared with those during charging occur, and an electric current runs from the positive to the negative electrode.
Consequently, the investigations of an ordinary temperature molten salt, which occurs as a liquid at room temperature is done (e.g. refer to Koura et al. : J. Electrochem. Soc. (USA), (1993) vol. 140, page 602). As ordinary temperature molten salts, complexes between aromatic quaternary ammonium halide such as an N-butylpyridinium, N-ethyl-N'-methylimidazolium or like, and an aluminum halide as well as mixtures of two or more lithium salts are known (refer to C. A. Angell et al. : Nature (UK), (1933) vol. 362, page 137). However, the former complexes have a problem of corrosion by halide ions, while the latter complexes are thermodynamically unstable supercooled liquids and have a problem in that they solidify with the lapse of time.
Japan Kohyo Publication No. 2000-508677 (pages 1-12), which is concerned with ionic compounds containing an anionic moiety bound to a cationic moiety M+m, discloses that those ionic compounds in which the cationic moiety M is hydroxonium, nitrosonium NO+, ammonium NH4 +, a metal cation having a valency of m, an organic cation having a valency of m or an organometallic cation having a valency of m and the anionic moiety corresponds to the formula RD-Y-C(C≡N)2 - or Z-C(C≡N)2 - can be used as ion-conducting material, for instance. However, there is a room for contrivance for modifying them to provide materials suited for use in constituting electrolytic solutions showing excellent basic performance.
The present inventors made various investigations to develop a material constituting an electrolytic solution, which is an ionic conductor, and as a result, paid their attention to the fact that an ionic conductor in liquid form, which is prepared by dissolving an electrolyte in a molten salt is useful, since the salt form no more shows volatility and can be handled safely. Then, the present inventors found out that (A) when an anion having a particular structure is comprised, ionic conductivity is excellent, this becomes preferable in materials constituting ionic conductors, and that when a content of a solvent is specified, both improvement in a problem in volatilization of a solvent and advancement in ionic conductivity can be sufficiently realized. Usually, when a content of a solvent is small in a material for an electrolytic solution, for example, the material is frozen at a low temperature of -55°C, ionic conductivity cannot be measured in some cases. However, it was found out that, by adopting such a form, a volatile matter is reduced, and excellent ionic conductivity is obtained without freezing at low temperatures, and that when the material constitutes an electrolytic solution, excellent fundamental performance can be exhibited. In addition, it was found out that, by (B) adopting a form containing two or more species of ionic liquids, even an ionic liquid, which is solidified alone at low temperatures and cannot be measured in ionic conductivity in some cases, can be excellent in ionic conductivity and, by including of ionic liquids having particular combination, or by having ionic conductivity above a particular range at a particular temperature, this material is suitable for a material constituting ionic conductors, thereby resulting in successful solution of the above-mentioned problems.
In addition, the present inventors variously studied an ionic material-containing composition which is suitably used for a material constituting an electrolytic solution, found out that its electrochemical property depends on a purity of impurities, and found out that, when a content of impurities in ionic materials comprised in the composition is specified, better electrochemical stability is exhibited. Then, it was found out that, in such the ionic material, by (C-1) adopting a form comprising an anion having a particular structure, in which a moisture content is specified, or by (C-2) adopting a form comprising a tricyanomethide anion, stability is further improved, and sufficient electrochemical stability can be exhibited also in utilities where water is taken into electrochemical devices, and it was found out that, in the above-mentioned ionic material, also by (C-3) adopting a form in which a viscosity at 40°C exhibits a specified value, and a water amount is specified, the similar action and effect can be exhibited, resulting in successful solution of the above-mentioned problems.
That is, the present invention is the following material for an electrolytic solution, composition containing an ionic material (this composition is referred to also as "an (the) ionic material-containing composition".), ion-conducting material and use thereof (lithium secondary battery, electrolytic condenser and electric double layer capacitor), and all of the following materials for an electrolytic solution and ionic material-containing compositions are effective for constituting ionic conductors excellent in electrochemical stability. Additionally, the term of "%" means percent.
(1) A material for an electrolytic solution containing an ionic compound,
, in the formula, X represents at least one element selected from among B, C, N, 0, Al, Si, P, S, As and Se; M1 and M2 are the same or different and each represents an organic linking group; Q represents an organic group; a is an integer of not less than 1, and b, c, d and e each independently is an integer of not less than 0, and 1 to 99% by mass of a solvent in 100% by mass of the material for an electrolytic solution.
, in the formula, X represents at least one element selected from among B, C, N, 0, Al, Si, P, S, As and Se; M1 and M2 are the same or different and each represents an organic linking group; Q represents an organic group; a is an integer of not less than 1, and b, c, d and e each independently is an integer of not less than 0.
which has 1 × 10-6 S/cm or more of ionic conductivity at -55°C.
, in the formula, X represents at least one element selected from among B, C, N, 0, Al, Si, P, S, As and Se; M1 and M2 are the same or different and each represents an organic linking group; Q represents an organic group; a is an integer of not less than 1, and b, c, d and e each independently is an integer of not less than 0,
wherein, at 40°C, the ionic material is a liquid state of 200 mPa·s or less,
Form (A) : (A) a form comprising the anion represented by the formula (1), and containing a solvent at 1 to 99% by mass in 100% by mass of the material for an electrolytic solution.
Form (B) : (B-1) a form containing two or more species of ionic liquids, in which an ammonium cation having no unsaturated bond and an ammonium cation having an unsaturated bond are contained, and the anion represented by the formula (1) is contained, (B-2) a form containing two or more species of ionic liquids, in which at least two species of ammonium cations having no unsaturated bond are contained, and any one or both of them have a ring (cyclic) structure, (B-3) a form containing two or more species of ionic liquids, in which at least two species of ammonium cations having an unsaturated bond are contained, and anions to be paired with the cations are different sprcies, and the anion represented by the formula (1) is contained, (B-4) a form containing two or more species of ionic liquids, in which ionic conductivity at -55°C is 1 × 10-6 S/cm or more, (B-5) a form containing one or two or more species of ionic liquids, in which a peak current reduction ratio at third cycle or later at voltage application in cyclic voltammetry measurement is 20% or more.
The above-mentioned ionic compounds (including an ionic liquid) is preferably a liquid state having fluidity and a certain specified volume at 40°C. Specifically, it is preferably a liquid having a viscosity of 200 mPa·s or less at 40°C, more preferably 100 mPa·s or less, furthermore preferably 50 mPa· s or less.
The material for an electrolytic solution of such a form has a reduced volatile matter and, moreover, is not frozen, for example, at a low temperature of -55°C, is excellent in ionic conductivity and, when the material constitutes an electrolytic solution, excellent fundamental performance can be exhibited.
As the above-mentioned solvent, any solvent may be used as far as it can improve ionic conductivity and, for example, water and an organic solvent are preferable. Examples of the organic solvent may include ether such as 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, crown ether, triethylene glycol methyl ether, tetraethylene glycol dimethyl ether, and dioxane; carbonate such as ethylene carbonate, propylene carbonate, diethyl carbonate, and methylethyl carbonate; chain carbonic acid esters such as dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, diphenyl carbonate, and methylphenyl carbonate; cyclic carbonic acid ester such as ethylene carbonate, propylene carbonate, ethylene 2,3-dimethylcarbonate,butylene carbonate,vinylene carbonate, and ethylene 2-vinylcarbonate; aliphatic carboxylic acid ester such as methyl formate, methyl acetate, propionic acid, methyl propionate, ethyl acetate, propyl acetate, butyl acetate, and amyl acetate; aromatic carboxylic acid esters such as methyl benzoate and ethyl benzoate; carboxylic acid ester such as γ-butyrolactone, γ-valerolactone, δ-valerolactone; phosphoric acid ester such as trimethyl phosphate, ethyldimethyl phosphate, diethylmethyl phosphate, and triethyl phosphate; nitrile such as acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, adiponitrile, and 2-methylglutaronitrile; amide such as N-methylformamide, N-ethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, N-methylpyrrolidone, and N-vinylpyrrolidone; sulfur compound such as dimethylsulfone, ethylmethylsulfone, diethylsulfone, sulfolane, 3-methylsulfolane, and 2,4-dimethylsulfolane; alcohol such as ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether; ether such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, 2,6-dimethyltetrahydrofuran, and tetrahydropyran; sulfoxides such as dimethyl sulfoxide, methylethyl sulfoxide, and diethyl sulfoxide; aromatic nitrile such as benzonitrile, and tolunitrile; nitromethane, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, and 3-methyl-2-oxazolidinone, and one or two or more species of them may be used.
The above-mentioned material for an electrolytic solution of the (A) form contains a cyano group-containing anion represented by the formula (1). Such an anion may be an anion constituting the above-mentioned ionic compound comprised in the material for an electrolytic solution of the present invention, or may be an anion constituting other components. By containing such an anion, the material for an electrolytic solution may be excellent in ionic conductivity, and suitable for materials constituting ionic conductors. In addition, the material for an electrolytic solution may contain other anions as far as they suitably act when constituting an electrolytic solution and, for example, contained may be the following anions;
Referring to the above-mentioned anion represented by the formula (1), X represents at least one element selected from among B, C, N, 0, Al, Si, P, As, and Se, and C, N or S is preferable. C or N is more preferable. C is furthermore preferable, and the form, in which X in the above formula (1) is carbon element (C), is one of the preferable embodiments in the present invention. M1 and M2 may be the same or different and each independently represents an organic linking group selected from among -S-, -O-, -SO2-, and -CO-, preferably -SO2-, or -CO-. Q represents an organic group and is preferably a hydrogen atom, a halogen atom, CpF(2p+1-q)Hq, OCpF(2p+1-q)Hq, SO2CpF(2p+1-q)Hq, CO2CpF(2p+1-q)Hq, COCpF(2p+1-q)Hq, SO3C6F5-rHr, or NO2 (wherein 1≤p≤6, o<q≤13, 0<r≤5), for instance, more preferably a fluorine atom, a chlorine atom, CpF(2p+1-q)Hq, or SO2CpF(2p+1-q)Hq. The symbol a is an integer of not less than 1, and the symbols b, c, d, and e each is an integer of not less than 0, with a, d, and e being dependent on the valence number of the element X; for example wherein X=sulfur atom, a=1, d=0, e=0, and X=nitrogen atom, (1) a=2, d=0, e=0, (2) a=1, d=1, e=0, or (3) a=1, d=0, e=1, and b and c are preferably 0.
in the formula, X represents at least one element selected from among B, C, N, 0, Al, Si, P, S, As and Se; M1 and M2 are the same or different and each represents an organic linking group; a is an integer of not less than 1, and b, c and d each independently is an integer of not less than 0.
As the anion represented by the formula (2), a dicyanamide anion (DCA),a tricyanomethide anion (TCM), and the like are preferable since they do not contain fluorine and are excellent in corrosion resistance in an electrode and the like and, in particular, a tricyanomethide anion is preferable.
In the formula, L represents C, Si, N, P, S or 0; R groups are the same or different and each represents an organic group and may be bonded together; s is an integer of 3, 4 or 5 and is a value determined by the valency of the element. In addition, it is preferable that such a cation is a cation forming the ionic compound contained in the material for an electrolytic solution of the present invention.
, in the formula, R is the same as in the formula (3). Among these, the onium cations of the following (I) to (IV) are preferable. Additionally, in the formula representing cations of the following (I) to (III), R1 to R12 are the same or different and each is an organic group and two of themmay be bonded together.
(II)Fivespeciesofunsaturatedonium cationsrepresented by the formula;
(IV) Linear onium cations in which R is a C1-C8 alkyl group. More preferred among such onium cations are those in which L in the above-mentioned formula (3) is a nitrogen atom. Still more preferred are six onium cations represented by the following formula (3-2), and chain onium cation such as triethylmethylammonium, dimethylethylpropylammonium, diethylmethylmethoxyethylammonium, trimethylpropylammonium, trimethylbutylammonium, and trimethylhexylammonium. Formula (3-2);
The compound comprising such onium cation and the above-mentioned anion can occur as an ordinary temperature molten salt capable of stably retaining its molten state at ordinary temperature. Therefore, the material for an electrolytic solution of the present invention, which comprises the compound can serve as an adequate material of ionic conductors in electrochemical devices and can endure a prolonged period of use. Additionally, the term "molten salt" as used herein means a salt capable of retaining its liquid state stably within the temperature range of from room temperature to 80°C.
In the material for an electrolytic solution of the above-mentioned (A) form, the ionic conductivity is preferably 1 × 10-7S/cm or more at -55°C. When the ionic conductivity is less than 1 × 10-7S/cm, there arises the possibility of the electrolytic solution prepared by using the material for an electrolytic solution according to the present invention failing to stably function while retaining a sufficient level of ionic conductivity with the lapse of time. The ionic conductivity is more preferably 1 × 10-6S/cm or more, and furthermore preferably 5 × 10-5S/cm or more, and still more preferably 1 × 10-4S/cm or more.
The above-mentioned material for an electrolytic solution preferably has a viscosity of 300 mPa·s or less at 25°C. When the viscosity is more than 300 mPa·s, the ionic conductivity may be improved sufficiently. The viscosity is more preferably 200 mPa·s or less, and furthermore preferably 100 mPa·s or less, and most preferably 50 mPa·s or less.
The method of measurement of the above-mentioned viscosity is not particularly restricted but the method which comprises using a model TV-20 cone/plate type viscometer (product of Tokimec Inc.) and performing the measurement at 25°C can judiciously be used.
The above-mentioned material for an electrolytic solution preferably has 50% or less of a peak reduction ratio after heating at 150°C for 50 hours. By adopting such a form, properties such as high electric conductivity, thermal stability and withstand voltage propertyinitially possessed by an electrolytic solution may be maintained for a long period, and it becomes possible to sufficiently improve stability for a long period of an electrolytic solution. The peak reduction ratio is more preferably 30% or less, furthermore preferably 20% or less.
Herein, a peak means a peak area, and a peak reduction ratio after heating at 150°C for 50 hours is a value obtained from (A-B)/A × 100, wherein A represents a peak of the ionic compound in the material for an electrolytic solution before heating and B represents a peak after heating at 150°C for 50 hours. The peak (mean peak area) can be measured by liquid chromatography (LC) analysis.
In the present invention, the ionic compound itself contained in a material for an electrolytic solution may satisfy such a numerical value range. That is, an ionic compound having a peak reduction ratio after heating at 150°C for 50 hours of 50% or less is also one aspect of the present invention.
In the above-mentioned material for an electrolytic solution of the (B-4) form, when the ionic conductivity is less than 1 × 10-6S/cm, there arises the possibility of the electrolytic solution prepared by using the material for an electrolytic solution according to the present invention failing to stably function while retaining a sufficient level of ionic conductivity with the lapse of time. The ionic conductivity is preferably 1 × 10-5/cm or more, and more preferably 5 × 10-5S/cm or more, and still more preferably 1 × 10-4S/cm or more.
The above-mentioned ionic conductivity can judiciously be measured by the method used in the above-mentioned form (A) .
The (B-2) form is, in two species of ammonium cations having no unsaturated bond, (a) a form in which one has a cyclic structure and the other has no cyclic structure, or (b) a form in which both have a cyclic structure. And such an ammonium cation having no unsaturated bond may be a cation in two or more species of the ionic liquids contained in the material for an electrolytic solution, or may be derived from other compounds.
Herein, the peak current reduction ratio at 2 cycle or later at voltage application is a value obtained by (ip1 - ipn) /ip1 × 100, wherein "ip1" represents a peak current at first cycle and "ipn" represents a peak current at a second cycle or later.
The cyclic voltammetry (CV) measurement is preferably performed by employing a standard voltammetry tool HSV-100 (trade name; manufactured by Hokuto Denko Corp.) using a three electrodes-cell under 30°C atmosphere. Measurement conditions in this case are as follows:
The above-mentioned material for an electrolytic solution in the form (B-5) preferably has a viscosity of 200 mPa·s or less at 40°C. When the viscosity is more than 200 mPa·s, the ionic conductivity may be improved sufficiently. The viscosity is more preferably 100 mPa·s or less and furthermore preferably 50 mPa·s or less.
The method of measurement of the above-mentioned viscosity is preferable, for example, the method which comprises using a model TV-20 cone/plate type viscometer (product of Tokimec Inc.) and performing the measurement at 25°C can judiciously be used.
And with the amount of the anion present, the lower limit is preferably 0.5 moles, and more preferably 0. 8 moles relative to the cation 1 mole in the material for electrolytic solution. And the upper limit is preferably 2.0 moles, and more preferably 1.2 moles.
In the case of the compound having the above-mentioned anion, alkali metal salt and/or alkaline earth metal salt of the anion represented by the formula (1) is preferable, and lithium salt is more preferable. As examples of such lithium salt is preferably, other than the lithium salt of above-mentioned anion, LiC(CN)3, LiSi(CN)3, LiB(CN)4, LiAl (CN)4, LiP(CN)2, LiP(CN)6, LiAs(CN)6, LiOCN, LiSCN or the like.
The above-mentioned material for an electrolytic solution may further contain other electrolyte salt. Preferred as such are perchloric acid quaternary ammonium salt such as tetraethylammonium perchlorate; tetrafluoroboric acid quaternary ammonium salt such as (C2H5)4NBF4; such quaternary ammonium salt as (C2H5)4NPF6; quaternary phosphonium salt such as (CH3)4P· BF4 and (C2H5)4P·BF4. Preferred from the solubility and ionic conductivity viewpoint is quaternary ammonium salt.
The above-mentioned inorganic oxide in minute particle formpreferably has a specific surface area as large as possible, preferably 5 m2/g or more, more preferably 50 m2/g or more, as determined by the BET method. Such inorganic oxide in minute particle form may have any crystal particle diameter provided that it can be mixed up with the other constituent elements of the electrolytic solution. A preferred size (mean crystal particle diameter) is 0.01 µm or more but 20 µm or less, more preferably 0.01 µm or more but 2 µm or less.
nitro compound such as p-nitrophenol, m-nitroacetophenone, and p-nitrobenzoic acid; phosphorus compound such as dibutylphosphate, monobutylphosphate, dioctyl phosphate, monooctyl octylphosphonate, and phosphoric acid; boron compound such as boric acid, and a complex compound of boric acid and polyhydric alcohol (ethylene glycol, glycerin, mannitol, polyvinyl alcohol or the like) or polysaccharide; nitroso compound; urea compound; arsenic compound; titanium compound; silicic compound; aluminic acid compound; nitric acid and nitrous acid compound; benzoic acid such as 2-hydroxy-N-methylbenzoicacidanddi(tri)hydroxybenzoicacid; acid such as gluconic acid, bichromic acid, sorbic acid, dicarboxylic acid, EDTA, fluorocarboxylic acid, picric acid, suberic acid, adipic acid, sebacic acid, heteropolyacid (tungstic acid, molybdic acid), gentisic acid, borodigentisic acid, salicylic acid, N-aminosalicylic acid, borodiprotocatechuic acid, borodipyrocatechol, bamonic acid, bonic acid, borodiresorcinic acid, resorcinic acid, borodiprotocachueric acid, glutamic acid and dithiocabamic acid; ester thereof, amide thereof and salt thereof; silane coupling agent; silicon compound such as silica, and aliminosilicate; amine compound such as triethylamine, and hexamethylenetetramine; L-amino acid; benzol; polyhydric phenol; 8-oxyqiunoline; hydroquinone; N-methylpyrocatechol; quinoline; sulfur compound such as thioanisole, thiocresol, and thiobenzoic acid; sorbitol; L-hystidine.
The ionic material may be (C-3) a form in which at 40°C the ionic material is a liquid state of 200 mPa·s or less, and an impurity content is 0.1% by mass or less, and a moisture content is 0.05 to 10% by mass, and also in this case, it is preferable that the anion represented by the formula (1) is contained.
(Method of measuring impurity content)
(1) ICP (measurement of cations such as silver ion and iron ion) Instrument: ICP light emitting spectrophotometric apparatus called SPS4000 (manufactured by Seiko Instruments Inc.) Method: 0.3 g of a sample is diluted by 10-fold with ion-exchanged water, and the resulting solution is measured.
Instrument: ion chromatography system called DX-500
(manufactured by Nippon Dionex Co., Ltd.)
Detector: electric conductivity detector called CD-20 Column: AS4A-SC
Method: 0.3g of a sample is diluted by 100-fold with ion-exchanged water, and the resulting solution is measured.
In the above-mentioned ionic material, a moisture content is preferably 0.05 to 10% by mass in 100% by mass of the ionic material. When the content is less than 0.05% by mass, moisture is difficult to manage, leading to higher cost. On the other hand, when the content exceeds 10% by mass, there is a possibility that electric stability cannot be sufficiently exhibited. The lower limit is preferably 0.1% by mass, and more preferably 0.5% by mass. The upper limit is preferably 5% by mass, and more preferably 3% by mass.
In sample preparation, 0.25 g of a measurement sample and 0.75 g of dehydrated acetonitrile are mixed in a glove box having a dew point of -80°C or less, and 0.5 g of a mixed solution is collected with a sufficiently dried Terumo syringe 2.5 ml in the glove box. Thereafter, moisture measurement is performed with a Karl Fischer moisture meter called AQ-7 (trade name, manufactured by Hiranuma Sangyo Co., Ltd.).
Referring to the above-mentioned formula (1), X represents preferably C, N, O or S, and more preferably C or N, and furthermore preferably C to be mentioned later herein. Q represents preferably a hydrogen atom; a halogen atom; an alkyl group, an allyl group, an acyl group, and substituted derivative thereof; CpF(2p+1-q)Hq, OCpF(2p+1-q)Hq, SO2CpF(2p+1-q)Hq, CO2CpF(2p+1-q)Hq, COCpF(2p+1-q)Hq, SO3C6F5-rHr, NO2 or the like (in each formula, 1≤p≤6, 0<q≤13, 0<r≤5). More preferred are a fluorine atom, a chlorine atom, CpF(2p+1-q)Hq and SO2CpF(2p+1-q)Hq. M1, M2, a, b, c, d, and e are the same as those mentioned hereinabove referring to the above-mentioned form (A).
In the anion represented by the above formula (1), X in the formula (1) is preferably N or C, and more preferably carbon element (C). That is, the anion represented by the above formula (1) is preferably the anion represented by the following formula (1'), which is the formula (1) in which X is C;
, in the formula, M1, M2, Q, a, b, c, d, and e are as described above.
As the ionic material comprising the above-mentioned anion, preferred are a compound formed of the anion and a proton; an organic salt of the anion; an inorganic salt of the anion. Among these, an inorganic salt of the anion is preferable, and an organic salt of the anion preferably comprises an onium cation. The onium cation means an organic group having a non-metal atom such as 0, N, S and P or a semi-metal atom.
⊖N(SO2R13)(SO2R14) (6)
⊖C(SO2R13)(SO2R14)(SO2R15) (7)
As the polymer, for example, preferred are one or two or more species of a polyvinyl polymer such as polyacrylonitrile, poly(meth)acrylic acid esters, polyvinyl chloride, and polyvinylidene fluoride; polyoxymethylene; a polyether polymer such as polyethylene oxide, and polypropylene oxide; a polyamide polymer such as nylon 6, and nylon 66; a polyester polymer such as polyethylene terephthalate; polystyrene, polyphosphazenes, polysiloxane, polysilane, polyvinylidene fluoride, polytetrafluoroethylene,a polycarbonate polymer,and anionene polymer.
As the above-mentioned organic solvent, preferable is a compound having better compatibility with a constitutional element in the ionic material-containing composition of the present invention, a great permittivity, high solubility of an electrolyte salt, a boiling point of 60°C or more, and a wide electrochemical stable range. More preferable is an organic solvent (non-aqueous solvent) having a low moisture content. Specific examples of such an organic solvent include solvents as described above in the above-mentioned electrolytic solution material of the (A) form, and one or two or more species thereof may be used. In particular, carbonic acid esters, aliphatic esters and ethers are more preferable, carbonates such as ethylene carbonate and propylene carbonate are furthermore preferable, and cyclic esters such as γ-butyrolactone and γ-valerolactone are most preferable.
In the above-mentioned ionic material-containing composition of the present invention, the ionic conductivity at 0°C is preferably 0.5 mS/cm or more. When the ionic conductivity is less than 0.5 mS/cm, there arises the possibility of the ionic conductor prepared by using the ionic material-containing composition of the present invention failing to stably function while retaining a sufficient level of ionic conductivity with the lapse of time. More preferably, the ionic conductivity is 2.0 mS/cm or more.
In the above-mentioned ionic material-containing composition, a difference between the upper limit and the lower limit of a potential window as measured by cyclic voltammetry (hereinafter, referred to as "CV") is preferably 2 V or more, more preferably 2.2V or more, further preferably 2.4V or more.
The CV measurement of potential window is preferably performed by employing a standard voltammetry tool called HSV-100 (trade name; manufactured by Hokuto Denko Corporation) using a 3 electrodes-cell under 30°C atmosphere. Measurement conditions in this case are as follows:
Scanning range: natural potential to 3 V, natural potential to -3 V
The production method for the ionic material-containing composition of the present invention is not particularly limited, but preferred is a method comprising a step of deriving an ionic material from a compound having the anion represented by the formula (1). Thereby, it becomes possible that an ionic material has a form preferable as a molten salt or a salt constituting a solid electrolyte. Such a production method preferably comprises a step of deriving an ionic material from a compound having the anionic structure represented by the formula (1) using a halide, for example, comprises a step of reacting a compound having the anion represented by the formula (1) with a halide or a carbonic acid compound, and the halide or carbonic acid compound preferably has an onium cation, or a cation comprising at least one metal atom selected from alkali metal atoms, alkaline earth metal atoms, transition metal atoms and rare metal atoms. One or two or more species of these preparation raw materials may be used, respectively.
in this case, examples of A in the formula (8) represents a hydrogen atom, at least one metal atom selected from alkali metal atoms, alkaline earth metal atoms, transition metal atoms and rare metal atoms, or a group having no metal element such as an ammonium group. From a viewpoint of suppression of an impurity content of the ionic material, a group having no metal element is preferable . In the formula (8), X, M1' M2, Q, a, b, c, d and e are as described above.
The above-mentioned production method may comprise a step of preparing a compound having the anion represented by the formula (1), which is used in the step of deriving an ionic material from a compound having the anion represented by the formula (1). In this case, a compound having the anion represented by the formula (1) is preferably prepared by reacting the above-mentioned compound having the anion represented by the formula (1) with a halide. Thereby, it becomes possible to appropriately set a structure of the anion represented by the formula (1) in the ionic material depending on performance or the like required for the ionic material-containing composition. In this case, an anion possessed by a compound having the anion which is a preparation raw material in the step of preparing a compound having the anion represented by the formula (1), and the anion represented by the formula (1) in the ionic material are not same.
In the above-mentioned step, letting a mole number of the compound having the anion represented by the formula (1) to be "a", and letting a mole number of the halide to be "b", a mole ratio (a/b) in the reaction is preferably 100/1 to 0.1/1. When the compound having the anion is less than 0.1, there is a possibility that the halide becomes too excessive, and a product is not obtained effectively, and there is a possibility that a halogen is mixed into the ionic material-containing composition, and poisons an electrode and the like. When the compound exceeds 100, there is a possibility that the compound having the anion becomes too excessive, and further improvement in a yield cannot be expected, and there is a possibility that a metal ion is mixed into the ionic material-containing composition, and performance of an electrochemical device is lowered. The mole ratio is more preferably 10/1 to 0.5/1.
The reaction condition of the above-mentioned step may be appropriately set depending on preparation raw materials and other reaction condition. And the reaction temperature is preferably -20 to 200°C, more preferably 0 to 100°C, furthermore preferably 10 to 60°C. The reaction pressure is preferably 1 × 102 to 1 × 108 Pa, more preferably 1 × 103 to 1 × 107 Pa, furthermore preferably 1 × 104 to 1 × 108 Pa. The reaction time is preferably 48 hours or less, more preferably 24 hours or less, further preferably 12 hours or less.
In the above-mentioned step, a reaction solvent is usually used. And as the reaction solvent, preferred are (1) aliphatic hydrocarbon such as hexane and octane; (2) alicyclic saturated hydrocarbon such as cyclohexane; (3) alicyclic unsaturated hydrocarbon such as cyclohexne; (4) aromatic hydrocarbon such as benzene, toluene and xylene; (5) ketone such as acetone and methyl ethyl ketone; (6) ester such as methyl acetate, ethyl acetate, butyl acetate and γ-butyrolactone; (7) halogenated hydrocarbon such as dichloroethane, chloroform and carbon tetrachloride; (8) ether such as diethyl ether, dioxane and dioxolane; (9) ether of alkylene glycol such as propylene glycol monomethyl ether acetate and diethylene glycol monomethyl ether acetate; (10) alcohol such as methyl alcohol, ethyl alcohol, butyl alcohol, isopropyl alcohol, ethylene glycol and propylene glycol monomethyl ether; (11) amide such as dimethylformamide and N-methylpyrrolidone; (12) sulfonic acid ester such as dimethyl sulfoxide; (13) carbonic acid ester such as dimethyl carbonate and diethyl carbonate; (14) alicyclic carbonic acid ester such as ethylene carbonate and propylene carbonate; (15) nitrile such as acetonitrile; (16) water, and the like. These may be used alone, or two or more of them may be used. Among these, (5), (6), (10), (11), (12), (13), (14), (15) and (16) are preferable. More preferable are (5), (10), (15) and (16).
In the production method for the ionic material-containing composition, after the above-mentioned steps, the treatment such as filtration of precipitates and the like, removal of a solvent, dehydration and drying under reduced pressure may be performed. For example, an ionic material-containing composition comprising an ionic material may be obtained by filtering produced precipitates, removing a solvent from a solvent containing an ionic material under condition such as vacuum, washing the material by dissolving in a solvent such as dichloromethane, adding a substance having dehydration effect such as MgSO4, dehydrating the resultingproducts, and performing drying under reduced pressure after removal of the solvent. The time of the washing treatment with a solvent may be appropriately set. And as the solvent, preferred are chloroform, ketone such as tetrahydrofuran and acetone, ether such as ethylene glycol dimethyl ether, acetonitrile, water and the like as well as dichloromethane. In addition, as the substance having dehydration effect, preferred are molecular sieve, CaCl2, CaO, CaSO4, K2CO3, active alumina, silica gel and the like as well as MgSO4, and the addition amount of the substance may be appropriately set depending on a kind of a product and a solvent.
The material for an electrolytic solution and ion-conductingmaterial of the present invention are judiciously used as an ionic conductor material in constituting cells or batteries having charge/discharge mechanisms, such as primary cells, lithium (ion) secondary batteries and fuel cells, electrolytic condensers, electric double layer capacitors, solar cells, electrochromic display devices and other electrochemical devices. Among them, they are preferably used tolithiumsecondary battery,electrolytic condenseror electric double layer capacitor. That is, a lithium secondary battery, electrolytic condenser or electric double layer capacitor using the material for an electrolytic solution or the ionic conductor material also constitutes a further aspect of the present invention.
Preferred as the above-mentioned ionic conductor is a mixture of an electrolyte and an organic solvent. When an organic solvent is used, this ionic conductor becomes that which is generally called "electrolytic solution". When a polymer is used, this conductor becomes that which is called "polymer solid electrolyte". The polymer solid electrolytes include those having an organic solvent as a plasticizer. The material for an electrolytic solution or the ion-conducting material of the present invention can judiciously be used as a substitute for the electrolyte or organic solvent in the electrolytic solution in such ionic conductor, and the ion-conducting material according to the present invention is also used as a polymer solid electrolyte. In an electrochemical device in which the material for an electrolytic solution or ion-conducting material according to the present invention are used as an ion-conducting material, at least one of these is constituted of the material for electrolytic solutions or ion-conducting material according to the present invention. Among these, use as a substitute for the organic solvent in the electrolytic solution, or as a polymer solid electrolyte is preferable.
In the case of lithium batteries, metallic lithium or an alloy of lithium and another metal is suitable as the material of the above-mentioned negative electrode. In the case of lithium ion batteries, polymers, organic materials, carbon obtained by baking pitch or the like, natural graphite, metal oxides, and like materials in which the phenomenon called intercalation is utilized are appropriate. In the case of electric double layer capacitors,activated carbon,porousmetal oxides, porous metals and conductive polymers are judiciously used.
A lithium secondary battery is constituted of the following basic constituent elements: a positive electrode, a negative electrode, separators occurring between the positive and negative electrodes, and an ionic conductor in which the material for an electrolytic solution or ionic conductor material according to the present invention is used. In this case, a lithium salt is contained as an electrolyte in the material for an electrolytic solution or ionic conductor material according to the present invention. Preferred as such a lithium secondary battery is a nonaqueous electrolyte lithium secondary battery, which is other than an aqueous electrolyte lithium secondary battery. A form of such lithium secondary battery is schematically shown, in cross section, in Fig. 1. In this lithium secondary battery, coke is used as the negative electrode active substance to be mentioned later herein, and a Co-comprising compound as the positive electrode active substance. During charge of such lithium secondary battery, the reaction C6Li → 6C + Li + e occurs on the negative electrode, the electron (e) generated on the negative electrode surface migrates through the electrolytic solution to the positive electrode surface in the manner of ionic conduction. On the positive electrode surface, the reaction CoO2 + Li + e → LiCoO2 occurs. An electric current thus flows from the negative electrode to the positive electrode. During discharge, the reverse reactions occur, and an electric current runs from the positive electrode to the negative electrode. In this manner, electricity can be stored or supplied by such ion-involving chemical reactions.
Suitable as the above-mentioned negative electrode active substance are metallic lithium and other materials capable of occluding and releasing lithium ions. Suited for use as the materials capable of occluding and releasing the above-mentioned lithium ions are metallic lithium; pyrolytic carbon; coke species such as pitch coke, needle coke and petroleum coke; graphite; glassy carbon; organic polymer-derived baking products which are produced by baking phenolic resins, furan resins and the like at an appropriate temperature to converting them into carbon;carbonfibers;carbon materialssuch asactivated carbon; polymers such as polyacetylene, polypyrrole and polyacene; lithium-comprising transition metal oxides or transition metal sulfides, e.g. Li4/3Ti5/3O4 and TiS2; metals capable of alloying with alkali metals, e.g. Al, Pb, Sn, Bi and Si; cubic intermetallic compounds capable of intercalating alkali metals, e.g. AlSb, Mg2Si and NiSi2, and lithium nitrogen compounds such as Li3-fGfN (G: transitionmetal). These may be used singly or in combination of two or more of them. Among these, metallic lithium and carbonaceous materials, which can occlude and release alkali metal ions, are more preferred.
The above-mentioned negative electrode current collector mentioned above may be made of any electron conductor that will not cause any chemical change within the cell or battery. Preferred are, among others, stainless steel, nickel, copper, titanium, carbon, conductive resins, and copper or stainless steel with carbon, nickel, titanium or the like adhering to or covering the surface thereof. Among these, copper and copper-comprising alloys are more preferred. These may be used singly or in combination of two or more of them. These negative electrode current collectors may be used after oxidation of the surface thereof. Furthermore, it is desirable that the collector surface be made uneven. The negative electrode current collector preferably has the form of a foil, film, sheet, net, punched body, lath, porous body, foamed body, or molded fiber group, for instance. Preferably, the current collector has a thickness of 1 to 500 µm.
The above symbol J represents at least one element selected from among Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb and B. The number x is within the range 0 ≤ x ≤ 1.2, y within the range 0 ≤ y ≤ 0.9, and z within the range 2.0 ≤ z ≤ 2.3, and the value of x varies as a result of cell or battery charge or discharge. Also employable as the positive electrode active substance are transition metal chalcogenides, vanadium oxides or niobium oxides, which may comprise lithium, conjugated polymer-based organic conductive substances, Chevrel phase compounds, and the like. The positive active substance particles preferably have an average particle diameter of 1 to 30 µm.
The above-mentioned positive electrode conductor material may be any of those electron-conductive materials which will not cause any chemical change at the charge/discharge voltage for the positive electrode active substance employed. Suitable are, among others, the same ones as mentioned hereinabove referring to the negative electrode conductor material; metals in powder form, such as aluminum and silver; conductive whiskers such as zinc oxide and potassium titanate; and conductive metal oxides such as titanium oxide. These may be used singly or two or more of them may be used combinedly. Among these, artificial graphite, acetylene black and nickel in powder form are more preferred. The positive electrode conductor material is preferably used in an amount of 1 to 50 parts by weight, more preferably 1 to 30 parts by weight, per 100 parts by weight of the positive electrode active substance. When carbon black or graphite is used, 2 to 15 parts by weight thereof is preferably used per 100 parts by weight of the positive electrode active substance.
The above-mentioned separators each is preferably made of a microporous insulating thin membrane showing a high level of ion permeability and a required level of mechanical strength and preferably functioning to close its pores at temperatures exceeding a certain level and thereby increase the resistance. (In this case, in the above-mentioned ion-conducting material, this preferable embodiment is the case where an electrolytic solution is used as a ionic conductor.) Suited for use as the material thereof from the organic solvent resistance and hydrophobicity viewpoint are, among others, porous synthetic resin films made of a polyolefin such as polyethylene or polypropylene, woven or nonwoven fabrics made of an organic material such as polypropylene or a fluorinated polyolefin, and woven or nonwoven fabrics made of glass fibers or an inorganic material. The separators preferably have a pore diameter within a range such that they are impermeable to the positive electrode active substance, negative electrode active substance, binders and conductor materials dropped away from the electrodes. The pore diameter is thus preferably 0.01 to 1 µm. The separator thickness is preferably 5 to 300 µm, more preferably 10 to 50 µm. The void content is preferably 30 to 80%.
An electrolytic condenser is constituted of the following fundamental constituent elements: a condenser element (including an anode foil, a cathode foil, an electrolytic paper sheet sandwiched between the anode foil and cathode foil and serving as a separator, and lead wires), an ionic conductor using a material for the electrolytic solution or the ion-conducting material of the present invention, an exterior case of a cylinder shape with a bottom, and a sealing body for sealing the exterior case. Fig. 2 (a) is aperspectiveviewof one formof the condenser element. The electrolytic condenser of the present invention may be obtained by impregnating a condenser element with an electrolytic solution using the material for an electrolytic solution or the ion-conductingmaterial of the present invention, serving as an ionic conductor, and accommodating the condenser element into an exterior case of a cylinder shape with a bottom, packaging a sealing body in an opening part of the exterior case and, at the same time, subjecting an end part of the exterior case to embossing procession and sealing the exterior case. Preferred as such electrolytic condenser is an aluminum electrolytic condenser, a tantalate electrolytic condenser, and niobium electrolytic condenser. One form of such aluminum electrolytic condenser is schematically shown, in cross section, in Fig. 2 (b). In a preferred form of such aluminum electrolytic condenser, a thin oxide (aluminum oxide) film or layer to serve as a dielectric is formed, by electrolytic anodic oxidation, on the aluminum foil surface roughened by rendering the same uneven by electrolytic etching.
The lead wire is preferably one comprising a connecting part making contact with the anode foil and the cathode foil, a round bar part and an external connecting part. This lead wire is electrically connected to the anode foil and the cathode foil by means of such as a stitch and ultrasound welding, respectively, at the connecting part. In addition, the connecting part and the round bar part in the lead wire are preferably made of high purity aluminum, and the external connecting part is preferably made of a copper-plated iron steel wire which has been subjected to solder plating. An aluminum oxide layer formed by anode oxidizing treatment with an aqueous ammoniumborate solution, an aqueous ammoniumphosphate solution or an aqueous ammonium adipate solution may be formed on a part or all of the surface of the connecting part with the cathode foil and the round bar part, or an insulating layer such as a ceramic coating layer made of Al2O3, SiO2 and ZrO2 or the like may be formed on a part or all of the surface of the connecting part with the cathode foil and the round bar part.
The sealing body is preferably provided with a through hole from which the lead wire leads out, and made of elastic rubber such as butyl rubber. And, as the butyl rubber, used may be a rubber elastic body produced by adding a reinforcing agent (carbon black or the like), a bulking agent (clay, talc, calcium carbonate or the like), a procession assistance (stearic acid, zinc oxide or the like), a vulcanizing agent or the like to crude rubber comprising a copolymer of isobutylene and isoprene, kneading the mixture, and rolling and molding the resulting mixture. As the vulcanizing agent, used may be an alkylphenol formalin resin; peroxide (dicumyl peroxide, 1,1-di-(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane or the like); quinoide (p-quinonedioxime, p,p'-dibenzoylquinonedioxime or the like); sulfur and the like. And, more preferably, when a surface of the sealing body is coated with a resin such as teflon (registered trademark), or a plate of bakelite or the like is applied thereto, permeability of a solvent steam is reduced.
The electrolytic condenser may be of a hermetic sealing structure, or of a structure in which the condenser is sealed in a resin case (described, for example, in Japan Kokai Publication No. 8-148384 ). In the case of an aluminum electrolytic condenser having a rubber sealing structure, since a gas is permeated through rubber to some extent, there is a possibility that a solvent is volatilized from the interior of a condenser into the air under high temperature environment, or a moisture is mixed into the interior of a condenser from the air under high temperature and high humidity environment. And there is a possibility that a capacitor causes an unpreferable change in property such as reduction in electrostatic capacity under such a severe environment. On the other hand, in a capacitor of a hermetic sealing structure or a structure in which the condenser is sealed into a resin case, since a permeation amount of a gas is extremely small, stable property is exhibited also on such a severe environment.
The active carbon obtained by the above-mentioned activation method is preferably heat-treated under an inert gas atmosphere, such as nitrogen, argon, helium or xenon, at 500 to 2500°C, more preferably 700 to 1500°C, to thereby eliminate unnecessary surface functional groups and/or develop the crystallinity of carbon for increasing the electronic conductivity. The active carbon may be in a crushed, granulated, granular, fibrous, felt-like, woven or sheet form, for instance. When it occurs as granules, it preferably has an average grain diameter of 30 µm or less from the viewpoint of electrode bulk density improvement and internal resistance reduction.
Preferred as the above-mentioned conductor material are, among others, carbon black species, such as acetylene black and Ketjen black, natural graphite, thermally expansible graphite, carbonfibers, rutheniumoxide, titaniumoxide, aluminum, nickel or like metal fibers. These may be used singly or in combination of two or more of them. Among these, acetylene black and Ketjen black are more preferred since they can effectively improve the conductivity in small amounts. The level of addition of the conductor material may vary according to the bulk density of the active carbon but preferably is 5 to 50% by mass, more preferably 10 to 30% by mass, relative to 100% by mass of the active carbon.
Suited for use as the above-mentioned binder substance are polytetrafluoroethylene, polyvinylidene fluoride, carboxymethylcellulose, fluoroolefin copolymer crosslinked polymers, polyvinyl alcohol, polyacrylic acid, polyimides, polyamides, polyurethanes, polyvinylpyrrolidone and a copolymerthereof,petroleum pitch,coalpitch,and phenolresins, among others. These may be used singly or in combination of two or more of them. The level of addition of the binder substance may vary according to the active carbon species and the form thereof, among others, but is preferably 0.5 to 30% by mass, more preferably 2 to 30% by mass, relative to 100% by mass of the active carbon.
Since the material for an electrolytic solution of the (A) form in the present invention has the above-mentioned construction, ionic conductivity is improved and, shows excellent properties at low temperatures, and the material is stable with the lapse of time, therefore, the material is preferable as a material for an electrolytic solution constituting ionic conductors, and corrosivity on an electrode and the like is not present, decomposition of an electrolyte salt is suppressed also at a high potential, and the material is also electrochemically stable. In addition, in the material for an electrolytic solution of the form (B) of the present invention, ionic conductivity is improved, corrosivity on an electrode and the like is not present, the material is stable with the lapse of time, decomposition of an electrolyte salt is suppressed also at high potential, and the material is also electrochemically stable. Further, the ionic material-containing composition and the ion-conducting material of the present invention can exhibit excellent fundamental performance such as electrochemical stability, and can be preferably used in a variety of utilities. Accordingly, such materials for electrolytic solutions, the ionic material-containing composition and ion-conducting material are judiciously used in constituting cells or batteries having charge/discharge mechanisms, such as primary cells, lithium (ion) secondary batteries and fuel cells, electrolytic condensers, electric double layer capacitors, solar cells, electrochromic display devices and other electrochemical devices.
The following examples illustrate the present invention more specifically. They are, however, by no means limitative of the scope of the invention. In the examples, "part (s) " means "part(s) by weight" and "%" represents "% by mass", unless otherwise specified.
Ion-exchanged water of 1% by mass was mixed into ethylmethylimidazolium dicyanamide to produce an ion-conducting material. The ion-conducting material was measured for ionic conductivity, and the ionic conductivities were 2.6 × 10-2 S/cm (25°C), 1.3 × 10-2 S/cm (0°C), 5.5 × 10-3 S/cm (-20°C), and 2.7 × 10-6 S/cm (-55°C). Results are shown in Table 1-1.
According to the same manner as in Example 1 except that a kind and an amount of an ionic liquid and a solvent shown in Table 1-1 were used, ionic conductivity was measured. These results are shown in Table 1-1. Table 1-1
Ionic liquid Solvent Ion conductivity(S/cm)
Species % by mass 25°C 0°C - 20°C -55°C
Example 1 EMImDCA Ion-exchange water 1 2.6 × 10-2 1.3 × 10-2 5.5 × 10-3 2.7 × 10-6
Example 2 EMImL7CA Ion-exchange water 10 3.4 × 10-2 2.2 × 10-2 1.1 × 10-2 1.2 × 10-3
Example 3 EMImDCA GBL 1 2.3 × 10-2 1.1 × 10-2 4.5 × 10-3 5.8 × 10-7
Example 4 EMImDCA GBL 10 2.6 × 10-2 1.1 × 10-2 4.5 × 10-3 5.2 × 10-5
Example 5 EMImDCA GBL 50 7.4 × 10-2 4.4 × 10-2 2.4 × 10-2 4.2 × 10-3
Example 6 EMImDCA GBL 65 7.0 × 10-2 4.4 × 10-2 2.7 × 10-2 6.1 × 10-3
Example 7 EMPyDCA GBL 65 5.8 × 10-2 3.6 ×10-2 2.2 × 10-2 5.0 × 10-3
Example 8 EMImTCM GBL 50 7.0 × 10-2 4.3 × 10-2 2.4 × 10-2 4.3 × 10-3
Example 9 EMImTCM GBL 65 6.7 × 10-2 4.3 × 10-2 2.7 × 10-2 6.2 × 10-3
Example 10 EMImTCM GBL 75 6.1 × 10-2 4.0 × 10-2 2.6 × 10-2 7.5 × 10-3
Example 11 EMImTCM GBL 85 5.6 × 10-2 3.7 × 10-2 2.5 × 10-2 9.1 × 10-3
Example 1 2 MeMeImDCA GBL 65 7.3 × 10-2 4.6 × 10-2 2.7 × 10-2 6.1 × 10-3
Example 13 EMImDCA GBL 75 6.4 × 10-2 4.1 × 10-2 2.6 × 10-2 7.4 × 10-2
Example 14 TEMADCA GBL 75 5.7 × 10-2 3.6 × 10-2 2.3 × 10-2 5.6 × 10-3
Example 15 EMImOCN GBL 50 3.4 × 10-2 9.7 × 10-3 2.8 × 10-3 4.1 × 10-4
Example 16 EMImOCN GBL 65 3.4 × 10-2 9.9 × 10-3 3.2 × 10-3 5.9 × 10-4
Example 17 EMImOCN GBL 75 3.0 × 10-2 9.0 × 10-3 3.1 × 10-3 7.3 × 10-4
Example 18 EMImDCA EG 10 2.7 × 10-2 1.3 × 10-2 4.5 × 10-3 5.7 × 10-6
Example 19 TMImDCA GBL 65 6.0 × 10-2 3.8 × 10-2 2.4 × 10-2 5.1 × 10-3
Comparative Example 1 EMImDCA Ion-exchange water 0.01 2.2 × 10-2 1.1 × 10-2 4.3 × 10-3 cannot be mesured
Comparative Example 2 EMImDCA GBL 0.01 1.8 × 10-2 1.0 × 10-2 3.9 × 10-3 cannot be mesured
Comparative Example 3 EMImDCA GBL 0.1 2.5 × 10-2 1.2 × 10-2 4.6 × 10-3 cannot be mesured
Comparative Example 4 EMImDCA EG 0.01 2.1 × 10-2 1.0 × 10-2 3.8 × 10-3 cannot be mesured
A sample was kept at 150°C for 50 hours using a dryer called DNF-400 (trade name; manufactured by Yamato Scientific Co., Ltd.).
The LC (liquid chromatography) analysis was performed in the same manner as in Example A, except that ethylmethylimidazolium dicyanamide (EMImDCA) was used, and a peak reduction ratio was determined. These results were shown in Table 1-2. Table 1-2
Sample (Ionic compound/Solvent) Mixing ratio (% by mass) Accelerating condition Peak reduction ratio(%)
Example A EM imTCM/GBL 35/65 150°C × 50 hou rs 17
Example B EM imDCA/GBL 35/65 150°C × 50 hours 38
Ethylmethylimidazolium dicyanamide and methylpropylpyrrolidiniumdicyanamide were mixed at amass ratio of 50 : 50 to produce an ion-conducting material. This ion-conductingmaterial was measured for ionic conductivity and, the ionic conductivities were 2.2 × 10-2 S/cm (25°C), 1.0 × 10-2 S/cm (0°C) , 4.0 × 10-3 S/cm (-20°C) and 1.6 × 10-4 S/cm (-55°C). These results are shown in Table 2.
According to the same manner as in Example 20 except that a composition and a mixing ratio shown in Table 2 were used, ionic conductivity was measured. Results are shown in Table 2. Table 2
Constitution Mixing ratio (% by mass) Ion conductivity (S/cm)
25°C 20°C 0°C -10°C -20°C -55°C
Example 20 EMImDCA/ MPrPyDCA 50/50 2.2 × 10-2 - 1.0 × 10-2 - 4.0 × 10-3 1.6 × 10-4
Example 21 EMImDCA/ MPrPyDCA 80/20 2.5 × 10-2 1.6 ×10-2 1.2 × 10-2 - 5.4 × 10-3 6.7 × 10-5
Example 22 EMImDCA/ MBPyDCA 50/50 - 1.5 × 10-2 - - 4.7 × 10-3 9.0 × 10-5
Example 23 EMImDCA/ EMImTCM 50/50 2.1 × 10-2 - 9.5 × 10-3 4.0 × 10-3 - 7.7 × 10-5
Example 24 EMImDCA/ EMPyDCA 50/50 2.5 × 10-2 - 1.2 × 10-2 5.2 × 10-3 - 2.9 × 10--4
Example 25 EMImDCA/ MBPyTFSI 50/50 1.0 × 10-2 - 4.8 × 10-3 1.7 × 10-3 - 4.3 × 10-5
Example 27 MPrPyDCA/ DEMEDCA 50/50 1.3 × 10-3 - 4.9 × 10-3 1.5 × 10-3 - 2.8 × 10-5
Example 28 EMImTFSI/ MBPyTFSI 50/50 5.8 × 10-3 - 2.1 × 10-3 5.7 × 10-4 - 8.1 × 10-6
Example 29 EMImTFSI/ TMHATFSI 50/50 2. 8 ×10-3 - 1.4 × 10-3 3.3 × 10-4 - 3.8 × 10-6
Example 30 EMImDCA/ MPrPyDCA/ Water 50/50/1. 1 2.2 × 10-2 - 1.0 × 10-2 - 5.2 × 10-3 2.0 × 10-4
Comparative Example 5 EMImTFSI - 6.5 × 10-3 - 3.0 × 10-3 9.1 × 10-4 - cannot be mesured
Comparative Example 6 MBPyTFSI - 2.5 × 10-3 - 7.1 × 10-4 1.6 × 10-4 - cannot be mesured
Comparative Example 7 TMMATFSI - 1.8 × 10-3 - cannot be mesured cannot be mesured - cannot be mesured
Comparative Example 8 EMImBzt - 2.3 × 10-4 - 1.2 × 10-5 - cannot be mesured cannot be mesured
EMImTFSI: 1-ethyl-3-methylimidazolium
bis(trifluoromethanesulfonylimide)
MBPyTFSI: methylbutylpyrrolidinium
TMHATFSI: trimethylhexylammonium
○ (good) : Theeffectofsuppressingelectrolyticsolution degradation due to voltage application is slightly high (a peak current reduction ratio at third cycle is 20% or more).
× (poor) : Theeffectofsuppressingelectrolyticsolution degradation due to voltage application is low (a peak current reduction ratio at third cycle is 5% or more).
Sample Mixing ratio (% by mass) Peak current(mA) Determination
1 cycle 2cycle 3cycle 4cycle 5cycle
Example 31 EMImDCA/EMImTCM 50/50 0.85 0.00 0.00 - - ⊚
Example 32 EMImDCA/EMImTCM 10/90 1.19 0.00 0.00 - - ⊚
Example 33 EMImDCA/EMImTCM 5/95 1.12 0.00 0.00 - - ⊚
Example 36 EMImDCA 100 0.07 0.00 0.00 - - ⊚
Example 37 EMImTCM 100 1.00 0.97 0.79 - - ○
Example 38 EMImOCN/GBL 35/65 0.07 0.0 0.0 - - ⊚
Comparative Example 9 EMImTFSI 100 0.17 0.30 0.35 0.35 0.35 ×
*1"EMImDCA/TCM (1 : 1) /GBL (mixingratio: 35/65) "means amixture of a mixture produced by mixing of EMImDCA and EMImTCM at a mass ratio of 1 : 1, and GBL, at a mixing ratio of 35/65.
Synthesis Example 1 <Synthesis of EMImTCM>
An anion-exchange resin (trade name "AMBERLITE IRA-400-OH" manufactured by Organo Corp.) was charged into a column tube, and a 5% aqueous solution of 3.3 g of sodium tricyanomethide (NaTCM) was passed therethrough at SV = 2 (2-fold amount of ion-exchange resin). Then, the column was washed by passing ion exchange water (200 ml) at SV = 5 (5-fold amount of ion-exchange resin), and a 1% aqueous solution of EMImBr (1.5 g) was passed therethrough at SV = 2. The resulting solution was concentrated in an evaporator to give the product of ethylmethylimidazoliumtricyanomethide (hereinafter, referred to as "EMImTCM").
According to the same manner as in Comparative Example 10 except that impurities described in Table 4 were used, adjustment was performed. This ion-conducting material was measured for a potential window, and results are shown in Table 4. Table 4
Sample Impurity Impurity concentration (% by mass) Moisture concentration (% by mass) Potential window(V)
Example 40 EMImTCM None - 0.6 -2.2~0.4
Comparative Example 10 EMImTCM Cl 0.5 0.6 -1.3~0.2
Comparative Example 11 EMImTCM AgNO3 0.5 0.6 -0.2~0.2
Comparative Example 12 EMImTCM Br 0.5 0.6 -1.0~0.2
Table 4 shows that in cyclic voltammogram (CV curve) of impurity content in the ion-conducting materials of Comparative Examples 10 to 12, potential window is narrower as compared with that of Example 40 (= a sample containing no impurities).
The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2004-140384 filed May 10, 2004 , entitled "MATERIAL FOR ELECTROLYTIC SOLUTION", Japanese Patent Application No. 2004-145161 filed May 14, 2004 , entitled "MATERIAL FOR ELECTROLYTIC SOLUTION", Japanese Patent Application No. 2004-366537 filed December 17, 2004 , entitled "IONIC MATERIAL-CONTAINING COMPOSITION, ION-CONDUCTING MATERIAL AND USE THEREOF", Japanese Patent Application No. 2004-376882 filed December 27, 2004 , entitled "MATERIAL FOR ELECTROLYTIC SOLUTION", and Japanese Patent Application No. 2005-000628 filed January 5, 2005 , entitled "MATERIAL FOR ELECTROLYTIC SOLUTION". The contents of that applications are incorporated herein by reference in their entirely.
A material for an electrolytic solution containing an ionic compound,
which comprises a cyano group-containing anion represented by the formula (1):
- X represents at least one element selected from among B, C, N, 0, Al, Si, P, S, As and Se;
M1 and M2 are the same or different and each represents an organic linking group;
Q represents at least one organic group selected from the group consisting of: a hydrogen atom, a halogen atom, C p F (2p+1-q) H q, OC p F (2p+1-q) H q, SO2C p F (2p+1-q) H q, CO2C p F (2p+1-q) H q, COC p F (2p+1-q) H q, SO 3 C 6 F 5-r H r, and NO2,
wherein 1 ≤ p ≤ 6, o < q ≤ 13, and 0 < r ≤ 5;
a is an integer of not less than 1;
b and c are both 0;
d is an integer of not less than 0; and
e is an integer of not less than 1;
The material for an electrolytic solution according to claim 1, wherein the organic group Q is OCpF(2p+1-q)Hq or CpF(2p+1-q)Hq.
The material for an electrolytic solution according to either of claims 1 or 2, which has 50% or less of a peak reduction ratio after heating at 150°C for 50 hours.
A composition containing an ionic material, wherein the ionic material comprises an ionic compound according to any of claims 1 to 3, wherein impurity content in said ionic material is not more than 0.1% by mass and moisture content in said ionic material is 0.05 to 10% by mass.
A composition containing an ionic material according to claim 4,
which comprises a cation represented by the formula (3) :
L represents C, Si, N, P, S or 0;
R groups are the same or different and each represents an organic group and may be bonded together;
s is an integer of 3, 4 or 5 and is a value determined by the valency of the element L.
A composition containing an ionic material according to claim 4 or 5, wherein, at 40°C, the ionic material is a liquid state of 200 mPa·s or less.
Anion-conductingmaterialcomprisingthecomposition containing an ionic material according to any one of claims 4 to 6.
A lithium secondary battery, an electrolytic condenser or an electric double layer capacitor, using the material for an electrolytic solution according to any one of claims 1 to 3, the composition according to any of claims 4 to 6, or the ion-conducting material according to claim 7.
EP20120194162 2004-05-10 2005-05-09 Material for electrolytic solution, ionic material-containing composition and use thereof Withdrawn EP2565886A1 (en)
EP20050739348 EP1745525A4 (en) 2004-05-10 2005-05-09 Material for electrolytic solution, ionic material-containing composition and use thereof
EP05739348.0 Division 2005-05-09
EP2565886A1 true true EP2565886A1 (en) 2013-03-06
EP20050739348 Withdrawn EP1745525A4 (en) 2004-05-10 2005-05-09 Material for electrolytic solution, ionic material-containing composition and use thereof
EP20120194162 Withdrawn EP2565886A1 (en) 2004-05-10 2005-05-09 Material for electrolytic solution, ionic material-containing composition and use thereof
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