Method of making lithium metal oxide cathode active material

A method of making a composition having lithium, transition metal and oxygen elements and preferably having vanadium as the transition metal with a unit structure of the nominal general formula LiV.sub.3 O.sub.8, such structure being able to accept lithium ions. The method as exemplified by the formation of Li.sub.1+x V.sub.3 O.sub.8 (0.ltoreq.x.ltoreq.0.2) comprises forming a mixture of intermingled particles of vanadium pentoxide (V.sub.2 O.sub.5) and lithium carbonate (Li.sub.2 CO.sub.3) each in an amount sufficient to provide a stoichiometric ratio of approximately 1:3 of lithium to vanadium respectively; compacting the particles by applying a compressive force to the intermingled particles; and heating the intermingled particles to an elevated temperature which is below the melting point of the LiV.sub.3 O.sub.8 product of the invention. The compacting and heating steps consolidate the particles into a densified body and cause diffusion of at least a portion of the elements across particle boundaries with release of carbon dioxide, thereby providing a lithium-vanadium-oxygen composition having a unit structure of Li.sub.1+x V.sub.3 O.sub.8.

FIELD OF THE INVENTION 
This invention relates to a method of making cathode active material and 
cathodes for electric current producing and storage cells and more 
particularly to a lithium metal oxide obtained through a new process of 
synthesis. 
BACKGROUND OF THE INVENTION 
Lithium-based cells or batteries often comprise cathodes of transition 
metal oxides which are used as intercalation compounds. The intercalation 
reaction involves the interstitial introduction of a guest species, 
namely, lithium into the host lattice of the transition metal oxide, 
essentially without structural modification of the host lattice. Such 
intercalation reaction is essentially reversible because suitable 
transition states are achieved for both the forward and reverse of the 
intercalation reaction. 
The basic components of a lithium cell typically include a lithium anode, a 
separator, and a metal oxide intercalation cathode active material such as 
a vanadium oxide compound. The cathode is usually a mixture of such oxide 
compound and other components such as graphite and an electrolyte/binder 
which provide ionic transport. During cell operation, incorporation of 
lithium in the metal oxide occurs. Examples of lithium metal oxides 
include lithium vanadium oxide (LiV.sub.3 O.sub.8) and lithium manganese 
oxide (LiMnO.sub.2). Lithium vanadium oxide is particularly favored. U.S. 
Pat. No. 5,013,620 describes a process for forming a lithium vanadium 
oxide compound by mixing precursor components containing lithium with 
vanadium pentoxide and then baking the mixture to a temperature in the 
range of about 700.degree. C. (centigrade) to 800.degree. C. to cause 
formation of LiV.sub.3 O.sub.8. The molten LiV.sub.3 O.sub.8 is then 
cooled and ground up into a powder. The melt process has certain 
disadvantages because it is difficult to handle molten metal oxides at 
high temperatures and special procedures are required. In addition, there 
is a reaction between the molten LiV.sub.3 O.sub.8 and most containers 
used for conducting the reaction which thereby causes contamination of the 
product. In addition, a significant amount of mechanical energy is 
required to grind the cooled, solidified LiV.sub.3 O.sub.8 product into a 
powder for inclusion in a cathode composition of an electrochemical cell. 
Despite these difficulties, typical melt processes, as described in U.S. 
Pat. No. 5,013,620, continue to be used to obtain positive electrode 
active material. Therefore, what is needed is a new process for preparing 
lithium metal oxide which is economical, which does not require handling 
metal oxide constituents in a molten state and which achieves good 
conversion of the starting materials to the final lithium metal oxide 
product. 
SUMMARY OF THE INVENTION 
In a preferred method, a lithium metal oxide composition is prepared having 
a unit structure characterized by the ability to insert lithium in an 
electrochemical reaction. Such compounds are referred to as intercalation 
compounds and they are transition metal chalcogen compounds having a 
reversible lithium insertion ability. It is preferred that the transition 
metal is one or more selected from the group consisting of V, Co, Mn, and 
Ni. The chalcogen compound is oxygen. These compounds may be represented 
by the general formula Li.sub.x Z.sub.y O.sub.a where Z represents a 
transition metal, and x, y and a are each greater than or equal to one. 
Particularly suitable oxide compounds favored for use as positive 
electrode active materials are LiV.sub.3 O.sub.8, LiMnO.sub.2, LiCoO.sub.2 
and LiNiO.sub.2. 
In the case of transition metals (Tm) nickel, cobalt and manganese, the 
general formula of the synthesized active material is Li.sub.x Tm.sub.y 
O.sub.z where 0.9.ltoreq.x.ltoreq.1.1, y=1 and 1.9.ltoreq.z.ltoreq.2.05. 
In the case of the lithiated vanadium oxide, the formula of the 
synthesized product is Li.sub.x V.sub.y O.sub.z where 
1.ltoreq.x.ltoreq.1.2, y=3 and 8.ltoreq.z.ltoreq.8.1. 
The process of the invention will be described with reference to the 
preparation of an active material having the nominal general 
stoichiometric formula Li.sub.1+x V.sub.3 O.sub.8, where 
0.ltoreq.x.ltoreq.0.2 as synthesized, and which is a reversible cathode 
for lithium based electrochemical cells having good energy, power and 
cycling capability. The Li.sub.1+x V.sub.3 O.sub.8 is also able to accept 
up to 3 moles of lithium during discharge resulting in Li.sub.4 V.sub.3 
O.sub.8 nominal general formula. The LiV.sub.3 O.sub.8 is prepared in a 
solid state synthesis process which lithiates a precursor metal oxide such 
as V.sub.2.sub.O.sub.5 in a solid state synthesis reaction between 
intermingled particles of a lithium-containing compound and the metal 
oxide. The lithium-containing compound is lithium carbonate (Li.sub.2 
CO.sub.3) or lithium hydroxide (LiOH). The solid state process is 
conducted by a sequence of steps, the first being forming a mixture 
comprising the intermingled particles of the metal oxide and the lithium 
compound each in an amount sufficient to provide a stoichiometric amount 
of the lithium and the metal of the oxide in the final product. In the 
case of the preparation of LiV.sub.3 O.sub.8, the overall reaction may be 
represented as follows: Li.sub.2 CO.sub.3 +3V.sub.2 O.sub.5 =2LiV.sub.3 
O.sub.8 +CO.sub.2. As can be seen, the stoichiometric ratio of lithium and 
vanadium in the reactants is 1:3 of Li:V. This corresponds to one mole 
equivalent of lithium carbonate for each 3 mole equivalent of vanadium 
pentoxide. It is preferred that an excess amount of the lithium compound 
be used. The particles are blended together and then compacted to form a 
densified body or pelletized powder. The compacted particles are densified 
to the point where their bulk density, after blending, on the basis of 
grams per milliliter is at least doubled desirably tripled and preferably 
the bulk density is increased by a factor of 4. The extent of compacting 
is also expressed as a percent of theoretical compact density, where 100% 
corresponds to the density of the Li.sub.2 CO.sub.3 /V.sub.2 O.sub.5 mix 
with no pores or air present. The compacting achieves at least 50% of 
theoretical compact density, desirably 60% and preferably 70%. After 
intermingling and compacting, the densified particles are heated to an 
elevated temperature which is below the melting point of the final lithium 
metal oxide product. The LiV.sub.3 O.sub.8 product has a melting point of 
about 620.degree. C. Desirably, the temperature is less than 600.degree. 
C. and it is preferred that the temperature be even lower, that is, no 
higher than about 585.degree. C. Lithium manganese oxide (LiMnO.sub.2) has 
a melting point of 1200.degree. C. In this case desirably the temperature 
is less than 1100.degree. C. and it is preferred to be lower than 
1000.degree. C. 
The particles are compacted by applying a force of pressure to a free 
surface of the intermingled particles in a press at a pressure of at least 
about 3,000 psi which is equivalent to about 200 bar of compressive force. 
It is preferred that the compressive force is on the order of 14,400 psi, 
1000 kg/cm.sup.2, or 980 bar. 
When the compacted particles are heated to an elevated temperature, 
diffusion of at least a portion of the elements, being one or more of 
transition metal (i.e. vanadium), lithium and oxygen, occurs across 
particle boundaries and release of effluent oxygen containing gas, (i.e. 
carbon dioxide) also occurs. The diffusion of one or more elements across 
particle boundaries causes at least partial homogenization or blending of 
such elements and concomitant release of effluent gas which provides a 
lithium-metal-oxygen composition. In the case of lithium-vanadium-oxygen, 
such composition has a unit structure represented by the nominal general 
formula Li.sub.1+x V.sub.3 O.sub.8, where 0.ltoreq.x.ltoreq.0.2, as 
synthesized. 
It is an object of the invention to provide a new method for preparing a 
lithium metal oxide positive electrode active material for a lithium 
battery. Another object is to provide a lithium battery having good charge 
and discharge capacity. Another object is to provide an improved 
electrochemical battery based on lithium which maintains its integrity 
over prolonged life cycle as compared to presently used batteries. Another 
object is to provide lithium vanadium oxide active material having a 
relatively low amount of precursor materials and contaminates whereby the 
composition approaches 100% by weight Li.sub.1+x V.sub.3 O.sub.8. Another 
object is to provide good conversion of the starting materials to the 
lithium-metal-oxide product. 
These and other objects, features and advantages will become apparent from 
the following description of the preferred embodiments, appended claims 
and accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In a preferred method, a lithium metal oxide composition is prepared having 
a unit structure characterized by the ability to insert lithium in an 
electrochemical reaction. A particularly preferred lithium-vanadium-oxide 
composition is prepared having a unit structure of the nominal general 
formula LiV.sub.3 O.sub.8, also represented by the nominal general formula 
Li.sub.1+x V.sub.3 O.sub.8 which is a reversible cathode for lithium based 
electrochemical cells. Other compositions include LiMnO.sub.2, LiCoO.sub.2 
and LiNiO.sub.2. Such compositions are able to insert lithium in and 
release it from the basic structure with good energy, power and cycling 
capability. The method of the invention will first be described with 
reference to the preparation of LiV.sub.3 O.sub.8 from lithium carbonate 
and vanadium pentoxide. 
The LiV.sub.3 O.sub.8 is prepared in a solid state synthesis process which 
lithiates a metal oxide in a solid phase reaction between intermingled 
particles of lithium carbonate (Li.sub.2 CO.sub.3) and vanadium pentoxide 
(V.sub.2 O.sub.5). The solid state process begins with forming a mixture 
comprising intermingled particles of vanadium pentoxide and lithium 
carbonate, each in an amount sufficient to provide approximately a 
stoichiometric amount of lithium and vanadium elements in the final 
product. The overall reaction may be represented as follows: Li.sub.2 
CO.sub.3 +3V.sub.2 O.sub.5 =2LiV.sub.3 O.sub.8 +CO.sub.2. As can be seen, 
the stoichiometric ratio of lithium and vanadium in the reactants is 1:3 
of Li:V. This corresponds to one mole equivalent of lithium carbonate for 
each 3-mole equivalent of vanadium pentoxide. It is preferred that an 
excess amount of lithium carbonate be present corresponding to 5% excess 
Li.sub.2 CO.sub.3, or 1.05 moles of lithium carbonate for every three 
moles of vanadium pentoxide. The particles are blended together and then 
compacted to densify them forming a densified body or pelletized powder. 
The compacted particles are densified to the point where their bulk 
density, after densifying is at least 50%, desirably 60% and preferably 
70% of the theoretical compacted density. The density of the Li.sub.2 
CO.sub.3 /V.sub.2 O.sub.5 mix with all of the air squeezed out is about 
3.13 g/cm.sup.3. A pellet density of 2.2 g/cm.sup.3 corresponds to 73% 
theoretical density. After intermingling and compacting, the densified 
particles are heated to an elevated temperature which is below the melting 
point of LiV.sub.3 O.sub.8. The LiV.sub.3 O.sub.8 has a melting point of 
about 620.degree. C. Desirably, the temperature is less than 600.degree. 
C. and it is preferred that the temperature be even lower, that is, no 
higher than about 585.degree. C. Conveniently, the compacted pellets are 
removed from the press prior to heating. The more complex process of hot 
pressing is not required to achieve good results, although it is within 
the scope of the invention. 
It is preferred that the particles be compacted by applying a force of 
pressure to a free surface of the intermingled particles by compacting 
them in a press at a pressure of at least about 3000 psi which is 
equivalent to about 200 bar of compressive force. 
When the compacted particles are heated to an elevated temperature, 
diffusion of at least a portion of the elements, being one or more of 
vanadium, lithium and oxygen, occurs across particle boundaries and 
release of carbon dioxide also occurs. The diffusion of one or more 
elements across particle boundaries causes at least partial homogenization 
or blending of such elements and concomitant release of carbon dioxide 
which provides a lithium-vanadium-oxygen composition having a unit 
structure represented by the nominal general formula Li.sub.1+x V.sub.3 
O.sub.8. The carbon dioxide is released as an effluent gas and leaves the 
solid product. A few parts per million (ppm) of carbon monoxide may also 
be present in the effluent. 
While not wishing to be held to any particular theory, it is thought that 
the process of the invention encourages diffusion particularly of lithium 
across vanadium pentoxide particle boundaries thus providing a lithiated 
metal oxide having a basic structure represented by the nominal general 
formula LiV.sub.3 O.sub.8. The solid state synthesis of lithiated vanadium 
oxide according to the invention provides conversion of over 80% and in 
the range of 90% to 100% of the vanadium pentoxide to lithiated vanadium 
oxide. In the solid state process of the invention, it is typical to 
achieve conversion of 95% to 100% of the vanadium pentoxide to a unit 
structure represented by the nominal general formula LiV.sub.3 O.sub.8. It 
is thought that some sintering may occur, however, the process relies upon 
chemical reaction between solid particles and not sintering to achieve the 
result. 
It is thought that high conversion of vanadium pentoxide and excellent 
diffusion of lithium across particle boundary lines is, at least in part, 
a result of combining proper particle size of the starting material, 
namely, lithium carbonate and vanadium pentoxide, along with compacting of 
the particles to enhance such diffusion of lithium across particle 
boundaries. 
The average particle size, which is the specific volume average particle 
size, of lithium carbonate and vanadium pentoxide is less than ten microns 
and preferably only a few microns or less. Desirably, the particles are 
one micron and preferably of submicron size, on the order of 0.5 microns. 
This particle size is achievable by grinding the lithium carbonate and 
vanadium pentoxide powders together. The bulk density of the intermingled 
powders after grinding but before compacting is on the order of 0.5 to 0.7 
grams per milliliter. This is equivalent to each gram of such powder 
occupying between 1.42 milliliters and 2 milliliters. The bulk density of 
the compacted powder, which is in the form of pellets or a densified body 
is on the order of 2 to 2.5 grams per milliliter. This is equivalent to 
each gram of such densified body occupying a volume on the order of 0.4 
milliliter to 0.5 milliliter. Accordingly, it can be seen that the process 
of compacting or densification results in the bulk density of the powder 
increasing by a factor in a range of 2 to 5. 
It has been found that good results are achieved when the compacted powder 
is heated in an oven for about 30 minutes at about 580.degree. C. to 
585.degree. C. Suitable times and temperature ranges for the heating are 
thought to be 15 to 120 minutes and 570.degree. to 600.degree. C. Although 
there does not appear to be an upper limit on the amount of time for 
proper heating, more than 30 minutes is thought to be unnecessary. It is 
thought that a minimum heating time of at least about 15 minutes is 
necessary to achieve suitable results. It is thought that a minimum 
temperature of about 570.degree. C. is needed to achieve acceptable 
results. An excess of the lithium-containing compound on the order of 5% 
facilitates the reaction, when the excess approached 20%, there was no 
significant difference in performance. 
EXAMPLE 
Lithiated vanadium oxide was synthesized in a solid state reaction having 
the overall general formula Li.sub.2 CO.sub.3 +3V.sub.2 O.sub.5 
=2LiV.sub.3 O.sub.8 +CO.sub.2. Powder of lithium carbonate of a 99.997% 
purity was obtained from Aldrich Chemical Co., Inc. of Milwaukee, Wis. The 
material was in particle form, had a melting point of approximately 
618.degree. C., a specific gravity of approximately 2.1 grams per cc, a 
particle size of less than 200 mesh (about 70 microns) and had the 
appearance of a white powder. The chemical abstract (CAS) number for 
lithium carbonate is 554-13-2 and its synonyms are camcolit, carbonic acid 
dilithium salt, candamide, carbonic acid lithium salt and dilithium 
carbonate. 
Vanadium pentoxide of the general formula V.sub.2 O.sub.5 was obtained from 
Kerr McGee, Johnson Matthey or Alpha Products of Danvers, Mass. It had a 
melting point of about 690.degree. C., decomposed at 1750.degree. C., a 
particle size of less than about 60 mesh (250 microns) and had a specific 
gravity of 3.357 grams per cc at 18.degree. C. It was a yellow to red 
crystalline powder. Vanadium pentoxide has a CAS number of 1314-62-1. 
Alternatively, the vanadium pentoxide may be prepared from ammonium 
metavanadate (NH.sub.4 VO.sub.3). The ammonium metavanadate is heated to a 
temperature of about 400.degree. C. to about 450.degree. C. to decompose 
it to vanadium pentoxide (V.sub.2 O.sub.5), usually in a crystalline form 
(in the presence of oxygen). The ammonium metavanadate is a solid 
crystalline material, usually a white to yellow powder. Processes for 
production of ammonium metavanadate are known in the art and will not be 
repeated here. Such processes are described in U.S. Pat. Nos. 3,063,795 
and 3,063,796; and processes for preparation of ammonium metavanadate and 
then for production of vanadium pentoxide therefrom are described in U.S. 
Pat. Nos. 3,728,442, 4,061,711 and 4,119,707, each of which is 
incorporated herein by reference in its entirety. 
The lithium carbonate and vanadium pentoxide were mixed together in a 
proportion to provide approximately a stoichiometric amount of lithium and 
vanadium elements where the stoichiometric amount is equivalent to b 1:3 l 
of Li:V. An excess amount of lithium carbonate was used equivalent to 
about 5% excess, which is 1.05:3 of Li:V. The molecular weight of lithium 
carbonate is approximately 74 grams per mole and the molecular weight of 
vanadium pentoxide is approximately 182 grams per mole. Three moles of 
vanadium pentoxide is equivalent to approximately 546 grams. The 5% excess 
of lithium carbonate corresponded to using 1.05 times 74 grams per mole of 
lithium carbonate which is equal to approximately 78 grams of lithium 
carbonate for every 546 grams of vanadium pentoxide. The weight ratio of 
lithium to vanadium pentoxide was calculated to be approximately 1:7 (i.e. 
546+78=7). 
In this example, approximately 250 grams of the lithium carbonate and 
vanadium pentoxide blend was used in the ratio described above. The mixed 
powder was blended and comminuted to reduce particle size in a Sears 
Kenmore 14-speed blender at the highest speed for 15 seconds with tumbling 
motion. A sample was taken and then the powder was blended for another 15 
seconds and a second sample was taken. Altogether eight samples were 
prepared with respective blending times of 15 or 30 seconds, and some of 
the samples were pressed into a densified pellet. Other samples were not 
pressed and were used for comparison purposes. Each sample was of a 1.0 
gram size. Some samples were heated for approximately 30 minutes and 
others for approximately 60 minutes as shown in Table 1. All samples were 
heated to a temperature of about 580.degree. C. to 585.degree. C. Those 
samples which were pressed were heated after pressing. 
Those samples which were pressed, were pressed in an apparatus 119 as shown 
in FIG. 1. Each of the 1 gram samples 127 to be pressed was placed in a 
cylindrical cavity 122 of an open top die 124 resting on a base element 
126. A charge of mixed powder 127 was placed into the cavity 122 and 
rested on base element 126. A hydraulically driven punch 128 was advanced 
into cavity 122 to apply a pressure of about 14,400 psi, (1,000 kg 
(kilogram) per cm.sup.2 (square centimeter), 980 bar) to a free surface 
129 of the powder charge 127 for two minutes to compress or densify the 
powder 127. 
The cross sectional area of the hydraulically driven punch 128 was 
approximately 0.894 cm.sup.2 and was in the form of a copper piston. The 
charge 127 to the press was usually on the order of 1 gram.+-.0.05 grams 
of powder. The pressure was usually maintained at about 430 bar for about 
five minutes. 
TABLE 1 
______________________________________ 
GRINDING/ 
BLENDING HEATING 
TIME TIME 
SAMPLE (sec) PRESSED? (min) 
______________________________________ 
1 15 NO 30 
2 30 NO 30 
3 15 YES 30 
4 30 YES 30 
5 15 NO 60 
6 30 NO 60 
7 15 YES 60 
8 30 YES 60 
______________________________________ 
TABLE 2 
______________________________________ 
V.sub.2 O.sub.5 
BLENDING 
SAMPLES WEIGHT % TIME/(sec) PRESSED? 
______________________________________ 
1 34.3 15 NO 
2 15.6 30 NO 
3 1.8 15 YES 
4 1.9 30 YES 
______________________________________ 
The V.sub.2 O.sub.5 content of the samples prepared in accordance with the 
method of invention, namely samples 3 and 4, were compared to comparison 
samples 1 and 2 as shown in Table 2. Of particular importance is the 
vanadium pentoxide weight content of each of the samples. The data in 
Table 2 clearly show that pressing the blended powder is exceptionally 
effective in making the reaction more complete. By pressing the powder 
mix, the content of V.sub.2 O.sub.5 was reduced from unacceptable levels, 
greater than 10% and ranging up to over 30%, to acceptable levels less 
than 10% and as low as 2% or less. 
The vanadium pentoxide content of each of the samples was analyzed by x-ray 
diffraction using an internal standard. 
Shown in FIGS. 2 and 3 are two x-ray diffractograms. The peak near 
20.degree. is due to V.sub.2 O.sub.5 and the peak near 23.degree. is due 
to LiV.sub.3 O.sub.8. 
For a mixture of V.sub.2 O.sub.5 and LiV.sub.3 O.sub.8 : 
let x=weight % of V.sub.2 O.sub.5 
100-x=weight % of LiV.sub.3 O.sub.8 
The weight % ratio (V.sub.2 O.sub.5)/(LiV.sub.3 O.sub.8)=x/(100-x). The 
amount of a component is proportional to the peak area. So the peak area 
ratio r is proportional to the weight % ratio. i.e. 
##EQU1## 
where K is the proportional constant. Rearranging the above equation 
gives: 
##EQU2## 
This equation can be used to find x(weight % V.sub.2 O.sub.5) from r (peak 
area ratio). The value of K can be determined from the diffractogram of a 
mixture with known amount of LiV.sub.3 O.sub.8 and V.sub.2 O.sub.5. 
In the case where LiOH is used in the solid state process, it is obtained 
in powder form of essentially colorless crystals with a specific gravity 
of about 2.54, particle size of less than 40 mesh (350 microns) and with a 
melting point of about 462.degree. C. The basic reaction of the process 
is: 
2 LiOH+3 V.sub.2 O.sub.5 .fwdarw.2 LiV.sub.3 O.sub.8 +H.sub.2 O. In this 
case, the oxygen containing effluent gas is water vapor. 
The process of the invention is used to form other lithium metal oxide 
active material compounds as in the following general formulas. In the 
case of manganese the preferred reaction is: 
4 LiOH+4 MnO.sub.2 .fwdarw.4 LiMnO.sub.2 +2 H.sub.2 O.sub.2 
The manganese dioxide is a black powder, available with a specific gravity 
of 5.0 and decomposes at about 535.degree. C. 
In the case of other lithium metal oxides the reactions may be generalized 
to O.sub.2 +2 Li.sub.2 CO.sub.3 +4 MO.fwdarw.4 LIMO.sub.2 +2 CO.sub.2, 
where M is Co or Ni. There is a basic difference between these reactions 
and the reaction for the preparation of LiV.sub.3 O.sub.8. In the 
preparation of LiV.sub.3 O.sub.8, the oxidation state of V does not change 
in the reaction. Whereas the oxidation states of Mn, Co or Ni change in 
the reactions above. The techniques of the invention are most appropriate 
for the V and Mn, as they do not require O.sub.2 from the atmosphere to 
participate in the reaction. Pressing the powder mixture into a pellet 
limits the availability of O.sub.2 for the reaction. There is also a 
fundamental difference between LiV.sub.3 O.sub.8 and the other three 
lithiated metal oxides as positive electrode material for lithium 
batteries. LiV.sub.3 O.sub.8 as synthesized is in the charged form. During 
the discharge of the cell, more lithium intercalates into the crystal of 
LiV.sub.3 O.sub.8 according to the reaction: 
EQU LiV.sub.3 O.sub.8 +x Li.sup.+ +x e.sup.- .fwdarw.Li.sub.1+x V.sub.3 O.sub.8 
LiMnO.sub.2, LiCoO.sub.2 and LiNiO.sub.2 as synthesized are in the 
discharged form. During the charge of the cell, some lithium is removed 
from the crystal according to the reaction: LIMO.sub.2 .fwdarw.Li.sub.1-x 
MO.sub.2 +x Li.sup.+ +xe.sup.- ; where M is Mn, Co or Ni. 
PREATION OF CATHODE AND CELL 
The cathode active material of the invention is used to prepare cathodes 
for lithium based electrochemical cells. FIG. 4 shows an electrochemical 
cell or battery 10 which has a negative electrode side 12, a positive 
electrode side 14, and a separator 16 there-between. In accordance with 
common usage, a battery may consist of one cell or multiple cells. The 
negative electrode is the anode during discharge, and the positive 
electrode is the cathode during discharge. The negative electrode side 
includes current collector 18, typically of nickel, iron, stainless steel, 
and/or copper foil, and a body of negative electrode material 20. The 
negative electrode material 20 is sometimes simply referred to as the 
negative electrode or negative electrode composition. The negative 
electrode side 12 may consist of only a metallic electrode 20 without a 
separately distinguishable current collector 18. The positive electrode 
side 14 includes current collector 22, typically of aluminum, nickel, 
iron, stainless steel, and/or copper foil, or such foils having a 
protective conducting coating foil, and a body of positive electrode 
material 24. The cathode composition 24 has a typical composition as set 
forth in Table 3 and includes the LiV.sub.3 O.sub.8 of the invention as 
the active material. The positive electrode material 24 is sometimes 
simply referred to as the positive electrode or positive electrode 
composition. The separator 16 is typically a solid electrolyte, 
electrolyte separator. Suitable electrolyte separators (polymer 
electrolyte) are described in U.S. Pat. Nos. 4,830,939, 4,990,413, and 
5,037,712, each of which is incorporated herein by reference in its 
entirety. The electrolyte separator is a solid organic polymer matrix 
containing an ionically conducting powder or liquid with an alkali metal 
salt and the liquid is an aprotic polar solvent. Cell 10 also includes a 
protective covering (40) which functions to prevent water and air from 
contacting the reactive layers of the cell 10. 
Cell 10 is preferably a laminar thin cell type including a lithium anode 
(negative electrode 20). Laminar thin-cell batteries containing lithium 
anodes are known in the art, and it will be appreciated that the cell can 
include various constructions such as bi-faced or bi-polar cell designs. 
Examples of cell constructions include a "jelly roll" or a fan folded 
laminate strip design as described in U.S. Pat. No. 4,879,190 incorporated 
herein by reference in its entirety. 
Because the cell utilizes a lithium anode layer 20, it is necessary to 
manufacture the cell in a water (humidity) free environment. Lithium is 
extremely reactive with water and if reacted, a passivation layer can form 
on the surface of the anode layer, reducing the efficiency of the layer, 
and increasing cell impedance. Accordingly, it is particularly desirable 
to manufacture the cell in an environment having a relative humidity at 
room temperature of less than 2% (less than 300 ppm water). An environment 
containing between 1 ppm and 50 ppm water, and preferably less than 1 or 
2 ppm water, produces a particularly efficient cell. 
TABLE 3 
______________________________________ 
TYPICAL CATHODE COMPOSITION 
PERCENT WEIGHT 
______________________________________ 
Active Material (LiV.sub.3 O.sub.8) 
45.0 
Carbon 10.0 
Propylene Carbonate (PC) 
33.0 
PolyEthylene Oxide (PEO) 
1.0 
PolyEthyleneGlycolDiAcrylate 
9.0 
(PEGDA) 
TriMethylPolyEthylene Oxide 
2.0 
TriAcrylate (TMPEOTA) 
______________________________________ 
The cathode composition containing the Li.sub.1+x V.sub.3 O.sub.8 active 
material of the invention is coated onto nickel foil, followed by electron 
beam curing (crosslinking/polymerization) of the acrylate component. Then 
the electrolyte is coated on top of the cathode and cured with ultraviolet 
light. The lithium electrode is applied on top of the electrolyte 
separator and the battery is finally placed in a flexible pouch 40 which 
is heat sealed under vacuum. 
The invention provides a lithium vanadium oxide compound of the general 
formula Li.sub.1+x V.sub.3 O.sub.8 having high purity, low V.sub.2 O.sub.5 
content, and good energy, power and cycling capability. The process of the 
invention is efficient and readily adaptable to continuous production of 
large quantities of active material in a manufacturing setting. 
While this invention has been described in terms of certain embodiments 
thereof, it is not intended that it be limited to the above description, 
but rather only to the extent set forth in the following claims. 
The embodiments of the invention in which an exclusive property or 
privilege is claimed are defined in the appended claims.