CA2227534A1 - Synthesis of lithiated transition metal oxides - Google Patents
Synthesis of lithiated transition metal oxides Download PDFInfo
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- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
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- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
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Abstract
A synthesis for lithiated transition metal oxide powders is provided which comprises reacting one or more transition metal compounds with a lithium compound, wherein the lithium compound is in a molten phase. The reaction mixture may contain additives, which act primarily to extend the temperature range of the molten phase of the lithium compound.
Description
.
CA 02227~34 1998-01-21 SYNTHESIS OF LITHIATED TRANSITION METAL OXIDES
Field of the Invention The invention relates to a process for the synthesis of lithiated transition metal oY~ ~oe,, from lithium compounds and one or more transition metal oxides, or ~G--I~ounds which doc~mpose to transition metal oxides, or react directly with the lithium unds, under the reaction conditions. The produced lithiated transition metal oxides or lithiated mixed transition metal oxides are suitable for use as a cathodic material in lithium ion battery Background of the Invention Lithiated transition metal oxide powders, such as the most . -.~cially used lithium cobalt ~oY~o~
LiCoO2, are utilized as cathode materials for the positive electrode in rechargeable lithium ion batteries. Lower cost materials, such as lithium nickel dioxide and lithium manganese dioxide, would be preferred, but have proven part~ ~ly laborious to make, because ut~l~ 7i ng prior art processes for their preparation involves multiple grinding steps and calcination stages.
Specific ~h? 1c~l, morphological and physical characteristics are required to sustain the desired electrical properties of the lithiated transition metal oxide powder over the many hundreds of sequential charge and ~ech~ge cycles ~ o~ during service. Current battery applications for powders ~f ~n~ high purity (>99%), homogeneity (of the lithiated structure), controlled particle sizes (usually within the range of 1 to 25 microns) and specific surface areas (usually within the range O.1 to 5 m2/g).
SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 Lithium transition metal O~1~D~ are usually made by variations on a st~n~d route, namely the solid state reaction of a preblended mixture of lithium oxide and the transition metal(II) oxide, in a current of air or O~yy.2ll, at ~e- ~L'~' atures ranging from about 400~ to 900~C. The lithium oxide is generated in-situ during the calcination, by the decomposition of a lithium . , ~nd, usually the carbonate or l-yd oxide.
It is also well known to use other lithium _ , ~nds, DYDmplary of which is the nitrate. The transition metal(II) oxide is also usually generated in-situ during the ~rlc~nAtion, by the ~D~ tion of a transition metal(II) l_- ,~und. For the syn~hDC~-~ of lithium cobalt ~O~1~D, the transition metal(II) ~...~ou..d is usually cobalt(II) carbonate, although the nitrate and hydroxide have also been u~ 7D~.
It is known that good ~Yi ng of the powders, prior to calcination, rccDlerates formation of the product as does incrDrs~ng the ~Alc~nAtion ~ ~ ature.
However, t ,-~ature also de~. 1nes the structure of the product. For DYr _1D, in the case of lithium cobalt synthDc~7~ at ~AlcinAtion ~ , ~atures as low as 400~C, lithium cobalt oxide having a spinel structure is formed, which DYhlh~ts ~ -hAt different properties to the desired, layered, "rock salt" structure pr~ e~
at 900~C.
Typically, in these prior art methods, as described for ~ D in U.S. patent 4,302,518 to J.B
~oo~Dno~yh et al., the reaction mixture is preblended, usually by gr~ n~ ng with a mortar and pestle or in a ball mill, and the powder may be opt~onAlly _ ~ ted, before being introduced into the furnace. After a predeter~ine~ cAlc~nAtion time period, the product is ved from the furnace, ey~nd and may be ~ cted again before being ~Al~ n~ for one or more addit~onAl SU~S 1 1 1 UTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA~ ~158 time periods to ensure complete conversion to lithium cobaltic dioxide. The final gr~ nAl ng produces the desired grain sized powder for use in the battery cathode.
During recent years the ~mph~c~s of research work has shifted away from the preparation of the lithium cobalt dioxide powder per se and ~o.~d the production of lithiated transition metal compounds requiring less costly, but equally effective, transition metals.
The patent literature provides many ~ ~l~s of other novel lithium ion ~y~t - and variations on the methods for the preparation thereof. In U.S. patent 5,160,712 issued to M.M Th~-k~ay et al., there are ~i~1ne~ lithium transition metal OY~c and methods for their preparation. The method comprises ~ ng the reactants, prior to heating the mixture to a tem.p~rature c~ 400~~, ~nd ~or a peri~d of ti~.e sufficient to form an essentially layered lithium transitions metal oxide structure (which includes certain spinel type structures), wherein at least part of the heating is conducted under a suitable G~yy~
cont~i n ~ ng atmosphere.
S~ ~ly, U.S. Patent 4,980,080 to A. Lecerf et al describes a process for the preparation of a material suitable for use as a cathode in an electro~hc i~l cell wherein the starting materials are a mixture of hydrated lithium hydroxide and ~k~l or cobalt oxide which are heated in air at ~ atures ranging between 600~ to 800~C. A two-stage reactant ~i ~i ng and reheating operation is ut~l 1 7~ to thereby accelerate the process.
As a further example, the hydrides of lithiated nickel dioxide and the secondary cells prepared therefrom are ~~ lo~e~ in U.S patent 5,180,574 SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCTICA~61'~~198 issued to U. Von Sacken. The ~---~ounds are prepared using nickel oxides, nickel hydroxide, and mixtures thereof, which are reacted with about a twenty five percent ~yc~cc of lithium hydroxide, at about 600~C in an atmosphere having a partial pressure of water vapour greater than two torr.
Despite the number and diversity of these prior art pro~eccD~ neverth~le~s, there has not been developed a satisfactory method of controlling the physical characteristics, such as particle size and surface area, of lithium cobalt dioxide powder and other lithium transition metal powders. Further, ~~ ~~cially viable processes, deleteriously, require multiple calcination steps. It has also been found that the prior art processes do not scale up essily without significant ad~ustments to the proce~es.
Summary of the Invention It is a primary ob~ective of the present invention to provide a selection of lithium transition metal oxide powders having specific particle size and size distribution and ~ olled microstructure for use in lithium ion battery ay~ ~ .
It i~ a Lu Ll-er ob~ective to provide a single stage synthetic route for the production of lithiated transition metal oxide ~o.l~l 3, In accordance with the present invention, there is provided a process for the synth~e~s of lithium transition metal oxide powders having predeter~i n~
particle size and controlled microstructure which comprises: reacting one or more transition metal compounds with a salt, oxide or hydroxide of lithium, said lithium compound being in a molten phase, and optionally, an additive which is functional to increase the effective molten phase ~ ~ature range of said lithium ~--l~ound, in an atmosphere funct~on~l to control SU~IllUTESHEET(RULE26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA~ 0158 the thermal ~composition of said lithium ~ , und and to maintain, or convert and maintain, the transition ~ metal compound in an oxidation state which corresponds to the oxidation state of the transition metal in the product, at a temr~rature and for a time effective to thereby form the desired lithium transition metal oxide.
Suitable lithium _~Lo~ln~s would be selected from the salts, oY~s or hyd~ of lithium.
The transition metal compounds would be selected from the O~ C of cobalt, nickel, manganese, vanadium, iron, titanium or chromium, or mixtures thereof. Preferably, the transition metal l_ _ u,-ds would be selected from the oxides of cobalt, n~ ~1 or manganese or mixtures thereof. Alternatively, suitable transition metal ~ , unds would be selected from the hydroxides, carbonates or salts of cobalt, nickel, manganese, vanadium or chromium or mixtures thereof.
The additives, which may be utilized optionally, are believed to ~ e formation of the liquid phase and extend the t- ,-~ature range of the molten phase of the lithium compound. The most effective additives have been found to be Al ~1 ~ metal ~ unds, part~ ~ly potassium or sodium hydroxide or mixtures thereof, which have very wide ranging molten t ~eratures ext~n~ng from 300 to above 1200~C. The preferred additive is potassium l-yd ~ide.
The reaction must be undertaken in an atmosphere which is L~ on~l to either ~V--~l L the transition metal l_ , ~nd to an oxide and/or to maintain the transition metal oxide in the correct oxidation state namely the same oxidation state as the tran~ition metal in the final product. Thus, the reaction atmosphere may ~o...~ lse an inert atmosphere, a r~l-c~ng SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 atmosphere or an ~Y~17~ng atmosphere ~ep~n~n~ upon the nature of the reactants.
As will be evident to one Ck~ 1 in the art, it is possible to produce the lithium transition metal oxide powders of predetermined particle size and controlled mic~o~ cture by controll~ n~ reaction time and temperature during the heating stage. The temperature ranges would extend from 200~C to 1200~C and the residence times from lh to 72h. The elevated t- ,~ature controls the structure and is n~c~s~y for the reaction to take place, whereas the residence times determine the resultant particle size and surface area.
The desired structure defines the reaction temperature and at this temperature the lithium ~ und and/or additive must be optimized whereby the lithium compound and molten medium provide the desired envi ~ t for growing the partlcl~q with the desired mi~o~L-~L~.e.
The reaction m~-han~sm postulated for the synthesis of lithium transition metal oxides was extrapolated from the discovery, that in the synth~s of lithium cobaltic ~ioY~ from cobalt (III) oxide and an ~Yc~s~ of lithium carbonate, the lithium carbonate is ret~ n~ in the molten state during the reaction. The reaction takes place above 720~C and in a static, neutral or non-oY~d~ 7i n~ atmosphere, with the lithium carbonate undergoing partial d~c_ ~osition to form carbon dioxide which is retained in the static atmosphere. The reaction thus G~ in the molten state, under optimum thermodynamic conditions. Without being bound by same, the molten phase is believed to exist, under the reaction conditions, as a coating on the solid transition metal oxide part~le~.
The ~ tion of the atmosphere should also be ad~usted to control the th~ ~ _ s~tion of the lithium ~ _~und. For ~ - ,le, if lithium carbonate SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA~G10~98 is used, sufficient carbon dioxide should be present in the atmosphere to retard its thermal ~omro~ition at reaction t~ -~ature.
As a ~ ~cial process, the process of the invention has several advantages over the methods of the prior art. It has the advantage that the preparation of lithium transition metai oY~ can be ~z~ h~-l in a single high t- -~ature heating step, in contrast to the prior art methods which require multiple firings under CAl ~-~ n~tion conditions. Since the reaction occurs in a molten phase, instead of as a solid state reaction, it has faster kinetics, thereby producing a more uniform, h~ _el,eous and repro~-~ihle powder product with controllable particle size and growth. Therefore, this improved process is more A ~hle to large scale ~ ~;ial production.
Advantageously, the produced lithium transition metal oxide powders exhibit low surface area, a narrow particle size distribution, and high ch~ ~c purity.
Description of the Drawings The method of the invention will now be described with reference to the A- ,-nying drawings, in which:
Figure 1 is a y~elAl ~ 7~ process flowsheet for the production of lithiated transition metal ~o~
powders by the process of the present invention;
Figure 2 is a pho~ oy~aph illustrating lithium cobalt ~oY~ powder prepared by the process of the present invention;
Figure 3 is a photo~i~oy aph illustrating lithium n~ ok~l dioxide powder prepared by the process of the present invention:
Figure 4 is a histogram illustrating size distribution ranges for lithium cobalt dioxide SUBSTITUTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA~6~198 powder prepared from cobaltic oxide by the process of the present invention;
Figure 5 is a histogram illustrating size distribution ranges for lithium cobalt dioxide powder prepared from cobaltous carbonate by the process of the present invention:
Figure 6 shows the first charge and ~cc~ge of the ele~L~ h~ ; C~ 1 cell wherein the cathode was prepared of LiNiO2 powder prepared by the process of the invention; and Figure 7 depicts part of the life cycle of the cell of Figure 6, with voltages between 4.15 and 3.0 volts.
Description of the Preferred Fmb~ -nt A finely divided lithium ~G...~ound and one or more transition metal compounds are well ~ Y~ in st~h~- -L~c quantities, or in the case of the lithium compound in an amount slightly greater than stoichiometrically reguired. The mixing step is critical hC~c~:~uc~ a poorly mixed reactant powder could lead to a product having a particle size distribution range which is too broad b~C~l~c~ the rate of particle ~wLh is ~re~nt upon the ~sr~sion of the lithium salt.
Suitable lithium _ _~unds are those effective upon heating to exist in the molten phase with no, or only partial ~s , -~tion thereof, t~k~ n~ place under the reaction con~ ~ tions. Such compounds would be selected from the salts, oxides or hydroxides of lithium. The preferred lithium ~_ , unds are lithium hydroxide for ~ ratures below and about 750~C and lithium carbonates for reaction temperatures above A
750~C. If LiOH is used, thermal ~ - ition of the LiOH can be controlled without ~on~ _ i tant inhibition SUBSTITUTE Sl ~ (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA9~/J~1~3 of the lithiation reaction, by doping the atmosphere with steam or water vapour.
The transition metal compounds would be selected from the oxides of cobalt, n~ ~k~l, manganese, vanadium, iron, titanium, chromium, or mixtures thereof.
Preferably, the transition metal ~- , unds would be selected from cobalt, ~ckDl or manganese or mixtures thereof. Alternatively, suitable transition metal compounds would be selected from the hydroxides, carbonates or salts of cobalt, nickel, manganese, vanadium or chromium or mixtures thereof. These latter transition metal ~_ , unds must be convertable to their respective oxides in-situ. It is most advantageous i$
the oxide added or produced in-situ is in the same oxidation state as the final product, so that the reaction can be carried out with the ~ ni of air or oxygen, and the stAh~ 1~ 7~tion of the molten lithium salt can then be effected by co~Al~cting the reaction in an enclosed atmosphere.
An additive comprising an alkali metal compound may be added to the reaction mixture.
Preferably, the additive would be selected from NaOH or KOH. The amount of additive used would range from 0.1 to 50 molar % based on the transition metal content. In the case of the synthesis of lithium cobalt ~ioY~ ~D
using the pathways described herein, it is not necDcc~y to add an additive in order to obtain a satisfactory product. However, in the production of lithium ni ~.kDl oxide or lithium manganese oxide the prDCDncD of an additive has been found to assist in opt~ 1 7~ ~g the kinetics of the reaction and st~h~l~ 7'1 ng the thermal o~tion of the lithium ~...~o~nd.
The. mixture is intro~ncD~ into a furnace where it is heated to ~ _~ atures ranging from 200 to 1200~C
for periods of time ranging from lh to 72h. The SU~S 111 UTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/'~5062 PCT/CA~G~ 0133 reaction atmosphere, as stated earlier herein, must be functional to either convert the transition metal ~_ _und to its oxide and/or to maintain the transition metal oxide in the desired oxidation state, namely that of the transition metal in the final product. Thus the atmosphere may be either inert, oY~ 7~ng or r~dl~oing and is readily de~e~ ~ef1 by one ~k~11e~ in the art.
The product and process of the i-.venLion will now be described with reffs~e..ce to the following non-limitative examples.
The synthesis of lithium cobaltic ~oY~ to form powders suitable for use in lithium ion battery ~y~ . Having reference to the flowsheet of Figure l, finely divided lithium carbonate and cobalt(III) oxide in sto~ ~h~ tric, or slightly greater than stoichiometric amounts, are ~ YeA in bl~n~ ~ ng step l. The cobalt (III) oxide may be synth~s~ 7e~ by various routes as will be described hereinafter. The mixture is inL~ c~1 into a furnace where it i8 heated in cAlç~nAtion step 2 to a ~ ,- ature in the range of about 750 to 900~C in a static, neutral or non-or~ n~ atmosphere, for a period of time of about 6 h to 72 h. Following ~Alc~n~tion, the sintered lithium cobaltic dioxide product is pulverized to break up agglomerates using a h; - ~ 11 or ball mill in ~ n~
step 3. An optional water wash ~ollows, wA ch~ n~ step 4, he~A~s~ advd,.~ageously it has been determined that water appears to l"- -ve most of the soluble impurities such as sulphur and sodium, as well as unreacted ~Yc~-cc lithium carbonate.
It is believed that by using an essentially pure cobaltic oxide powder and lithium carbonate the process of the invention yields lithium cobaltic having a constant particle size and surface area, SIJ~ JTE SHEET (RULE 26) CA 02227~34 1998-01-21 irrespective of the shape and size of the reaction vessel. The physical properties of the powder can be simply controlled by the furnace temperature and residence time. Additionally, if an ~Yc~sc of lithium carbonate is utilized (i.e. a 5 to 10% stoi~h~ stric ~Y~cc over cobalt), then a lithium to cobalt atomic ratio of 1:1 in the powder product is obtA~ ne~ .
The cobalt (III) oxide can be prepared by several routes, namely from cobaltic h~Y i ne sulphate solution or cobaltic pentammine sulphate solution, by precipitation with sodium or potassium h~dl~xide, or from a soluble cobalt(II) salt by oxidation with a strong oxidizing agent, or from cobalt carbonate by high temperature oxidation in air, or can alternatively be obt~ineA from ~ -~cial suppliers.
Preparation of Cobaltic Oxide from Cobaltic ~ ne Sulphate 72 g of sodium hydroxide (ex 8DH Ltd), ~ccOlved in one litre of water, was slowly added to a 3L solution which contAi n~ 180 g of cobaltic heYr ~ne sulphate (ex Sherritt Inc), at 90~C. The mixture was stirred and heated to its ho~ 1 ~ng point, for 30 minutes, to drive off the copro~ A, The slurry was cooled and the s~ .atant liquor decanted off. The black precipitate was wAche~ twice with a similar quantity of pure water, before it was filtered and washed twice to 1- ~v~ soluble ~ , ~ties. It was then dried in an oven at 120~C for about 24 hours. The product analyzed as hydrated cobaltic oxide with 61.1%
w/w cobalt. The above procedure was repeated twice more and the product analyzed at 61.5 and 61.3% w/w cobalt.
SUBSTITUTE SHEET (RULE 26) CA 02227534 l998-0l-2l 2 PCT/CA9~/~S~3 E~MPLE 3 Preparation of Cobaltic oxide from Cobaltous Sulphate 2.24 kg of . ~um sulphate was ~i-Q~olved in 20 litre_ of aqueous cobaltou~ lp~te solution, with a cobalt ,v ~- tration of 100 g/L at 50~C. 3.46 kg of r _ ~ ~ ( as 29% aqueous : - ~) was added slowly, until any of the in~ ~te precipitate had r~solved.
The resultant cobaltous y~ sulphate solution was oYid~ed to cobaltic y~ i~ sulphate by the addition of l.Z8 kg of l~ydL~y~ peroxide (as a 30% solution in water).
The cobaltic pentammine sulphate solution was heated to 90~C and 4.2 L aqueous sodium hydroxide (240 g/L) added at a rate of 300 ml/min. The mixture wa_ stirred during this addition and finally heated to its boiling point to drive off any ~ ~g : ~. The ~y~,..atant liquor was decanted from the settled slurry.
Any soluble 1 _~.ities were ,~ _~ed from the black precipitate by twice repulping it with pure water, foll~ ed ~y filtration and ~ Qh~g the filtrate twice more with pure water. After drying the black solid in an oven at 120~C for about 24 hours, it analyzed as hydrated cobaltic oxide with 61.1% w/w cobalt.
Conversion of Cobaltic Oxide into Lithium Cobaltic Dioxide over Different Time Periods 1.3 kg of dried cobaltic oxide, y.e~a.el as in Example 3 above, and 0.9 kg of lithium -~ bo -te (ex Cyprus Foote) were mixed ~ her in a V hl ~ for 4 hours. 300 g aliquots of the mixture were lo~ded into one litre CN1000 alumina c~ihl~Q (ex Coors). Each crucible was heated in a NEY box furnace at 900~C.
Individual crucibles were ,~ ~e-~ after seven different time periods (1, 3, 6, 12, 24, 36 and 48 hours). The resultant products were broken up into p~ Q, the size SlJts~ 1 UTE SHEET (RULE 26) -CA 02227~34 1998-01-21 W 097/05062 PCT/CA9G~ 15&
of a pea, in a mortar and pestle, and fed to a h- ill, for light deaggl~ ation, and the powder r~q5 ' Ll~o~yl~ a 400 mesh screen. The minus 400 mesh fraction was analyzed; the results are given in Table I. The particle size of the ~ increases as the r~ time of the reactant mixture in the furnace is increased, ;~ting that the particles grow in situ.
The surface area of the ~ ~d~L decreased to a constant value as the particle size increases.
TABLE I
Time (hrs) D 50% (um) Surf2ace Area m /g 1 3.9 1.73 3 5.2 1.15 6 7.2 0.77 12 8.8 0.45 24 10.9 0.35 36 12.4 0.36 48 15.2 0.38 Co--ve ~ion of Cobalt Oxide into Lithium Cobaltic D~AJX~
at Different Te~..~atures A blend of dried cobaltic oxide and lithium carbonate was mixed as in Example 4. 300 g aliquots were loaded into one litre CN 1000 alumina crucibles and placed in the NEY furnace at different temperatures (800, 900 and 1000~C) for 36 hours. The resultant products were fed to a hammermill, for light deagglomeration, and segregated on a 400 mesh screen.
The minus 400 mesh powder was analyzed and the results, given in Table II, show that the growth of the particles increases as the furn~ing ~~ ,A~ature increases.
S~J~S 111 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 W 097/05062 PCT/CA~'C~58 TABLE II
Temp (~C)D 50% (um) Surf~ce Area (m /g) 800 3.6 0.98 900 12.4 0.36 1000 24.1 0.44 Comparison of the Synth~-s of Lithium Cobaltic Dioxide from Cobaltic Oxide and Cobaltous Carbonate Powders of either cobaltic oxide (prepared as in Example 2 above) or cobaltous carbonate (ex Aldrich Chemical) were blended with lithium carbonate, in a V
blender, as in Example 4, and various amounts were charged to various sizes and -shApe~ of alumina crucible.
The mixtures were each reacted in a NEY furnace for 36 hours at 900~C, and then deaggl~ ated as in ~Y- _l~ 4.
The analytical results are displayed as his~oy~ in Figures 4 and 5. From Figure 4, it can be seen that the furnaced product from cobaltic oxide has particles with a similar median and size range irrespective of the crucible size, shape or lo~dln~. Figure 5, hcs~v~r, shows that dioxide made from cobaltous carbonate is sensitive to crucible size, shape and lo~ . Two additional runs (52A and 66 in Figure 5) were carried out in which the cobaltous carbonate was first ~ecc _-~cd before it could react with lithium carbonate, i.e. the furnace t~mro~ature was first held at 400~C for 6 hours (to ~ ~s~ the carbonate to cobalt oxide) and then the ~ _ ature was raised to 900~C to _ _l~te the reaction of the resultant oxide with lithium carbonate.
The analytical results show that crl~c1hle shape and size do not now appear to affect the particle size of the lithium cobaltic ~1ox~
SU~ 111 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97105062 PCT/CA~G
E~U~MPLE 7 The effect of Excess Lithium Carbonate on the Preparation of Lithium Cobaltic Dioxide.
Mixtures of cobaltic oxide and lithium carbonate were made up as in ~Y~ 1~ 4, in which the lithium carbonate content was set at different stoichiometric ~.D~C~ ( -20%, 0%, 20%, 50% and 100~).
Equal quantities of each mixture were treated in the furnace as before (900~C for 36 hours). The products were then analyzed, and the results are given in Table III. It can be seen that the largest particle sizes are achieved when an eYc~cc of lithium carbonate is present, indicating that part~ Ate growth is assisted by the presence of molten lithium carbonate.
TABLE III
Target (FY~.~CC ~) D 50% (um) Surface Area (m2/g) -20 2.6 1.99 ~5 12.4 0.36 ~20 14.2 0.41 l50 14.2 0.46 +100 11.3 0.63 The Effect of C- ~~tion on the Preparation of Lithium Cobaltic Dioxide Cobaltic oxide and lithium carbonate were hl~n~, as in F ~ _le 4, and the resultant powder was sub~ected to _ _~-tion by pl~ ng it in a 2 cm diameter mold and ~d~ n~ 5 tons of pressure to the piston. The 1 n long ~ t had a density of 1.8 g/cc ~ ~~ed to 0.5 g/cc for the original powder bl~n~e~. Several comr~cts were pl~c~ in a crucible and placed in a NEY
furnace at 900~C for two different time periods (12 and 24 hours). The products were analyzed, and the results SU~S 111 UTE SHEET (RULE 26) CA 02227~34 l998-0l-2l are given in Table IV. It can be seen that the rate of growth of the lithium cobaltic dioxide particles greatly increased when compared to the product from the original powder. In fact, the compacted product obt~in~ after 12 hours is similar to that obt~ from the ~omr~ted powder in 36 hours (Ref. rrable 1).
TABLE IV
Lithium Cobaltic Dioxide made from C~ ted Powder 'rime (hrs) D 50% -400 mesh (um) 12 13.3 24 13.9 The synthesis of lithium nickel ~ox~e to form powders suitable for use in lithium ion battery ~y~te Having reference to the flowsheet of Figure 1, lithine, LiOH.H2O, nickel hydroxide, and potassium and/or sodium hydroxide are ground together and are well mixed in stoichiometric amounts in bl~n~3~ ng step 1. The mixture is introduced to a furnace where it is heated (step 2) in an oxygen ContA ining atmosphere to a temperature in the range of 500 to 1000~C, for a period of time of about 10 to 50 hours. Following caiclnation, the sintered lithium nickel dioxide is optionally pulverized to break up aggll - ates using a hammermill or ball mill (step 3). A water wash 4 is carried out followed by a final oven drying step 5, and c~ ccification 6 to ~e~;ov2r the lithium n~--k~ x1 powder product.
Preparation of Lithiated Nickel Dioxide with and without Potassium Hydroxide 46g of lithine, LiOH.H2O, 93 g of n~Ck~l hydroxide and 7.3 g of potassium hydroxide (85 % KOH) were ground SIJ~3 111 UTE SHEET (RULE 26) -CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA9~ 198 and mixed together in a mortar and a pestle for about 20 minutes. The 1.1:1.0:0.1 (Li:Ni:K) mole ratio blend was heated in a furnace at 800~C for 20 hours in air, then was removed from the furnace, pulverized, washed with distilled water and dried in an oven at 150~C for 5 hours. The resultant product, which r~ ee~ through a 400 mesh sieve, analyzed, by an average particle size of 11.5 microns, and BET (Brl~n~e~-Emmett-Teller) surface area of 0.74m2/g. After reheating at 600~C for 1 hour, the surface area was reduced to 0.32 m2/g. ~ ic~l analysis i n~ ir~ted that the potassium content was 0.002 ~ by weight, that is that the potassium _ ,7unds can be washed out almost completely and that the KOH does not add impurity ph~Q~s or ~...~o~nds to the final LiNiO2 product.
For _ ,~~ison, a -e~con~ Q~mrl~ of LiNiO2 was prepared as described above, but without the inclusion of the potassium hydl~xide. X-ray diffraction ~ n~ c~ted that LiNiO2 had been obt~; n~, but an SEM mi~l~y a~h showed that the average particle was about 3.0 microns which is significantly smaller than the particles obtained in the presence of KOH, under the same conditions.
For further comparison, a thlrd sample of LiNiO2 was prepared as above, but without the inclusion of the potassium hydroxide and with a larger ~YC~QS of lithium l.ydl~ide. The starting material corresp~e~
to Li:Ni mole ratio of 1.2:1.0, that is a 20% ~cc lithium hydroxide, compared to 10% excess lithium hydroxide in the previous two samples. After heating the materials at 800~C for 20 hours, it was found that the particle size was also about 3.0 microns, clearly trating that the pr~e~nc~ of potassium hydl~ide is n~ee~y to increase the growth rate of LiNiO2 particles.
SU~:i 1 1 1 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA~ 198 Preparation and Electrochemical Cell Perfor~nc~ of Lithiated Nickel Dioxide with Potassium hydroxide at a Lower Temperature 92g of lithium hydroxide, 185g of nickel hydroxide and 14.7 of potassium hyd.~xide (85% KOH) were ground together with a mortar and a pestle for about 20 minutes, the blend heated at 700~C for 20 hours in air, and the product pulverized then washed with water, and finally dried in an oven at 150~C. The product which p~c-s~ through a 400 mesh sieve, analyzed as a single phase of LiNiO2, with lattice constants a=2.880 A and b=14.206 A, which agree very well with the reference data (Journal of Power Sources 54 (1995) 109-114). The sample particle sizes, as viewed by SEM were between 1 and 3 microns, and an average particle size, as ~ ~ed by MicrotracTM (light scattering method), of 2.5 microns. t~h~ analysis gave lithium, n l -~k~l and potassium contents as 7.18% and 59.91% and 0.002% by weight respectively; the Lheo.etical values for Li and Ni for LiNiO2 are 7.11% and 60.11%. When impurities due to the reactants are taken into a~o~--L, the fo. ~1 A for the product wa~ postulated to be Lil_XNil+xO2 with-0.02<x<0.02. The value of x in Lil_XNil+XO2 made by other ~.~v~.~tional methods is usually x>0.02. This in~in~tes that a better guality product is obt~ne~ with potassium h~d-~ide in the reaction mixture, probably because the potassium ~ es better distributlon of the lithium within the melt at reaction ~ ture.
An electroche ~cal cell, with a cathode, separator, anode and an electrolyte wa~ ~-- hl ed in which the cathode was made of the LiNiO2 powder from above, mixed to a paste, with 9% by weight of Super S
carbon black and 1~ by weight EPDM (ethylene propylene diene terpolymer), and spread on aluminium foil before SUBSTITUTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA96/'~158 being allowed to dry; the paste coverage was typ~c~lly 20 mg/cm2 and cathode area was 1.2 x 1.2 cm2. The electrolyte was 1 M lithium perchlorate, LiCl04 in propylene carbonate. Lithium metal was used for the anode and Isotactic Poly~lo~ylene (Celgard 2500TM) as the separator. Cell hardware was st~i nl q8~ steel with an aluminium substrate, sealed with an O-ring and stack pressure provided by a spring. Lithium foil was att~he~ to the stainless steel hardware and the cathode att~ch~ to the al~ ~nl substrate. Charge ~ ~--L was ad~usted to correspond to x-0.5 Li deintercalation in Li1-_XNil+XO2 during a charge of 20 hours, and the discharge current ad~usted to correspond to x~0.5 Li intercalation in 10 hours. The charge voltage was up to 4.15 V and the ~ h~ge voltage down to 3.0 V. Figure 6 shows the first charge and ~ch~ge curve of the cell using LiNiO2 as cathode materials. The first charge ~-~r~ ty is seen to be 200 mAh/g and the first ~ h~ge ~p~c~ty 145 mAh/g. The cycle life is shown in Figure 7 with voltages between 4.15V and 3.0 V. The fade rates are very low, and significantly less than materials made by prior art at this working voltage range and at this ~r~ ty.
Example 12 Preparation of Lithiated Nickel Dioxide with Sodium ~xide A sample of LiNiO2 was made in the same way as the first sample in Example 9, with sodium hyd ~ide in place of the potassium hydroxide: that is, 46g of lithine, LiOH.H2O, 93 g of n~k~l l.ydlo~ide and 4.5 g sodium hydroxide (97% NaOH) were ground and ~Ye~
together in a mortar and a pestle for about 20 minutes.
The 1.1:1.0:0.1 (Li:Ni:Na) mole ratio blend was heated in a furnace at 800~C for 20 hours in air, then was removed from the furnace, pulverized, w~h~ with SlJ~S 1 1 1 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 2~
distilled water and dried in an oven at 150~C for 5 hours. The resultant product, which pA~C~ through a 400 mesh sieve, analyzed by X-ray diffraction as pure single phase of LiNiO2 with a low sodium content (less than 5% of the original was left). The X-ray diffraction pattern of the LiNiO2 product agreed with the stAn~d data, and no impurity phase was ob~elved.
In conclusion, sodium hydroxide can be used instead of potassium hyd ~ide ~or this preparation.
F---, le 13 Preparation of Lithiated Cobalt D~Y~ with and without Potassium Hydroxide The effect of the potassium hydroxide on the growth rate of particles during the syn~h~C~ of lithium cobalt dioxide, LiCoO2 was investigated. Firstly, LiCoO2 was prepared by the same method as the first ~r _ le of LiNiO2 was prepared in F le 10, that is, 46g of lithine, LiOH.H20, 97g of cobalt oxide (contA~nin~ 60~ cobalt by weight) and 7.3 g potassium hydroxide (85 % ROH~ were ground and mixed ~~y~Lher in a mortar and pestle for about 20 minutes. The 1.1:1.0:0.1 (Li:Co:K) mole ratio blend was heated in a furnace at 800~C for 20 hours in air, then was l~ v~d from the furnace, pulverized, washed with distilled water and dried in an oven at 150~C for 5 hours. The resultant product, which passed through a 400 mesh sieve, analyzed by X-ray diffraction as a very pure single phase of LiCoO2. The peak positions agree well with the st~A~d materials, with lattice constants a~2.819~0.001 A and b=14.07_0.01A. Mi~ ~L~acTM analysis show an average particle size of 8.5 microns. ~h~ ~ CAl analysis gave lithium and cobalt of 7.34% and 59.72% by weight, t very close to 1:1 mole ratio, with a very low potassium content of 0.031%, showing that the potassium ~ nds SUBSTITUTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA96,'~19 can be easily washed away after the calcination reaction.
For l~ ~ison, a second C~mrl~ of LiCoO2 was made, as above, but without the addition of the potassium hydroxide, that is, 46g of lithine, LiOH.H20 and 97g of cobalt oxide (cont~ n~ ng 60.5% cobalt by weight) were ground and mixed together in a mortar and a pestle for about 20 minutes. The 1.1:1.0 (Li:Co) mole ratio blend was heated in a furnace at 800~C for 20 hours in alr, then was removed from the furnace, pulverized, washed with dist1ll~ water and dried in an oven at 150~C for 5 hours. The resultant product, which passed through a 400 mesh sieve, analyzed by X-ray diffraction as a very pure single phase of ~iCoO2 with lattice constants calculated as a=2.819+0.001 A and b=14.07+0.01A. Chemical analysis shows lithium and cobalt ~on~e..ts are 7.58% and 59.17%, re~e~L~vely, that is the lithium ratio is slightly higher than stoichiometric requirement. However, the average particle size was only 4.9 microns, 1n~ ting that part~ of LiCoO2 prepared with the 10% potassium hydloxide in the blend grow to be Al L twice as large as those obt~ n~ without potassium hyd oxlde, under the same conditions.
Example 14 Dea~qll ation of the Product Particles by W~Sh~ n~ or Two samples of lithium nickel ~1oY~ were prepared by a similar method to that outl~ in FYr 1 ~
ll, except that larger crucibles were used, each containing 500 g of the reactant mixture. The calcination was carried out at two different temperatures, 750 and 800~C, with an atmosphere of o~yy~-- present in the furnace at the lower t , ~ature, and air instead of o~yye-- at the h~ghD~ t- ,e~ature.
S~J~ 111 ~JTE SHEET (RULE 26) 2~
Two examples of the product ~rom each calcination were treated as ~ollows. One part was deagglomerated by lightly grinding in a ceramic ball mill, and the other part was deagglomerated by simply washing it with water. The median particle sizes of the resultant powders are given in Table V for a comparison of median particle size in um of calcined product after deagglomeration of a mill or with a simple water wash.
Table V
Median Particle ~ize (um) 750~C with ~2 800~C with air Water Wash9.7 8.0 Milling 7.4 6.3 Both treatments lead to approximately the same particle size in the ~inal product, so there is a process choice in the post treat~ent o~ the calcined product to convert it to powder: deagglomeration in a mill, or washing with water.
Figure 2 is a photograph of the particles made when lithium cobalt dioxide (as prepared in Example 4, with 36 h in the ~urnace) is milled to deagglomerate the product particles.
The micrograph shows particles with smooth faceted sur~aces indicating that the particles comprise one crystal or an agglomerate of a small number of crystals with an average diameter in the range o~ 1 to 25 microns as evidenced by the typical distance between and relative scarcity of grain boundaries intersecting the particle surfaces. This characteristic is in contrast to that of particles of lithium nickel dioxide produced by the methods described in the prior art which comprise a multi-crystal agglomerate AMENDED S~EET
, ~ CA 02227~34 1998-01-21 ~, , with a cons~ituent crystal size cf less than 1 micron consequently having a large number cf grain boundaries intersecting the particle surfaces and giving the particles a rough knobbly appearance. Figure 3 is a photograph of the particles which result from a water wash treatment of lithium nickel dioxide, as made and treated by the procedure described in this example. These results clearly demonstrate that the particles made by the process of this invention grow in a single step, and that their unique size and structure do not result from the comminuti~n o~ a large calcined mass.
It will be understood, of course, that other embodiments and examples o~ the invention will be readily apparent to a person skilled in the art, the scope and purview of the invention being de~ined in the appended claims.
AMENDED SltEET
CA 02227~34 1998-01-21 SYNTHESIS OF LITHIATED TRANSITION METAL OXIDES
Field of the Invention The invention relates to a process for the synthesis of lithiated transition metal oY~ ~oe,, from lithium compounds and one or more transition metal oxides, or ~G--I~ounds which doc~mpose to transition metal oxides, or react directly with the lithium unds, under the reaction conditions. The produced lithiated transition metal oxides or lithiated mixed transition metal oxides are suitable for use as a cathodic material in lithium ion battery Background of the Invention Lithiated transition metal oxide powders, such as the most . -.~cially used lithium cobalt ~oY~o~
LiCoO2, are utilized as cathode materials for the positive electrode in rechargeable lithium ion batteries. Lower cost materials, such as lithium nickel dioxide and lithium manganese dioxide, would be preferred, but have proven part~ ~ly laborious to make, because ut~l~ 7i ng prior art processes for their preparation involves multiple grinding steps and calcination stages.
Specific ~h? 1c~l, morphological and physical characteristics are required to sustain the desired electrical properties of the lithiated transition metal oxide powder over the many hundreds of sequential charge and ~ech~ge cycles ~ o~ during service. Current battery applications for powders ~f ~n~ high purity (>99%), homogeneity (of the lithiated structure), controlled particle sizes (usually within the range of 1 to 25 microns) and specific surface areas (usually within the range O.1 to 5 m2/g).
SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 Lithium transition metal O~1~D~ are usually made by variations on a st~n~d route, namely the solid state reaction of a preblended mixture of lithium oxide and the transition metal(II) oxide, in a current of air or O~yy.2ll, at ~e- ~L'~' atures ranging from about 400~ to 900~C. The lithium oxide is generated in-situ during the calcination, by the decomposition of a lithium . , ~nd, usually the carbonate or l-yd oxide.
It is also well known to use other lithium _ , ~nds, DYDmplary of which is the nitrate. The transition metal(II) oxide is also usually generated in-situ during the ~rlc~nAtion, by the ~D~ tion of a transition metal(II) l_- ,~und. For the syn~hDC~-~ of lithium cobalt ~O~1~D, the transition metal(II) ~...~ou..d is usually cobalt(II) carbonate, although the nitrate and hydroxide have also been u~ 7D~.
It is known that good ~Yi ng of the powders, prior to calcination, rccDlerates formation of the product as does incrDrs~ng the ~Alc~nAtion ~ ~ ature.
However, t ,-~ature also de~. 1nes the structure of the product. For DYr _1D, in the case of lithium cobalt synthDc~7~ at ~AlcinAtion ~ , ~atures as low as 400~C, lithium cobalt oxide having a spinel structure is formed, which DYhlh~ts ~ -hAt different properties to the desired, layered, "rock salt" structure pr~ e~
at 900~C.
Typically, in these prior art methods, as described for ~ D in U.S. patent 4,302,518 to J.B
~oo~Dno~yh et al., the reaction mixture is preblended, usually by gr~ n~ ng with a mortar and pestle or in a ball mill, and the powder may be opt~onAlly _ ~ ted, before being introduced into the furnace. After a predeter~ine~ cAlc~nAtion time period, the product is ved from the furnace, ey~nd and may be ~ cted again before being ~Al~ n~ for one or more addit~onAl SU~S 1 1 1 UTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA~ ~158 time periods to ensure complete conversion to lithium cobaltic dioxide. The final gr~ nAl ng produces the desired grain sized powder for use in the battery cathode.
During recent years the ~mph~c~s of research work has shifted away from the preparation of the lithium cobalt dioxide powder per se and ~o.~d the production of lithiated transition metal compounds requiring less costly, but equally effective, transition metals.
The patent literature provides many ~ ~l~s of other novel lithium ion ~y~t - and variations on the methods for the preparation thereof. In U.S. patent 5,160,712 issued to M.M Th~-k~ay et al., there are ~i~1ne~ lithium transition metal OY~c and methods for their preparation. The method comprises ~ ng the reactants, prior to heating the mixture to a tem.p~rature c~ 400~~, ~nd ~or a peri~d of ti~.e sufficient to form an essentially layered lithium transitions metal oxide structure (which includes certain spinel type structures), wherein at least part of the heating is conducted under a suitable G~yy~
cont~i n ~ ng atmosphere.
S~ ~ly, U.S. Patent 4,980,080 to A. Lecerf et al describes a process for the preparation of a material suitable for use as a cathode in an electro~hc i~l cell wherein the starting materials are a mixture of hydrated lithium hydroxide and ~k~l or cobalt oxide which are heated in air at ~ atures ranging between 600~ to 800~C. A two-stage reactant ~i ~i ng and reheating operation is ut~l 1 7~ to thereby accelerate the process.
As a further example, the hydrides of lithiated nickel dioxide and the secondary cells prepared therefrom are ~~ lo~e~ in U.S patent 5,180,574 SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCTICA~61'~~198 issued to U. Von Sacken. The ~---~ounds are prepared using nickel oxides, nickel hydroxide, and mixtures thereof, which are reacted with about a twenty five percent ~yc~cc of lithium hydroxide, at about 600~C in an atmosphere having a partial pressure of water vapour greater than two torr.
Despite the number and diversity of these prior art pro~eccD~ neverth~le~s, there has not been developed a satisfactory method of controlling the physical characteristics, such as particle size and surface area, of lithium cobalt dioxide powder and other lithium transition metal powders. Further, ~~ ~~cially viable processes, deleteriously, require multiple calcination steps. It has also been found that the prior art processes do not scale up essily without significant ad~ustments to the proce~es.
Summary of the Invention It is a primary ob~ective of the present invention to provide a selection of lithium transition metal oxide powders having specific particle size and size distribution and ~ olled microstructure for use in lithium ion battery ay~ ~ .
It i~ a Lu Ll-er ob~ective to provide a single stage synthetic route for the production of lithiated transition metal oxide ~o.l~l 3, In accordance with the present invention, there is provided a process for the synth~e~s of lithium transition metal oxide powders having predeter~i n~
particle size and controlled microstructure which comprises: reacting one or more transition metal compounds with a salt, oxide or hydroxide of lithium, said lithium compound being in a molten phase, and optionally, an additive which is functional to increase the effective molten phase ~ ~ature range of said lithium ~--l~ound, in an atmosphere funct~on~l to control SU~IllUTESHEET(RULE26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA~ 0158 the thermal ~composition of said lithium ~ , und and to maintain, or convert and maintain, the transition ~ metal compound in an oxidation state which corresponds to the oxidation state of the transition metal in the product, at a temr~rature and for a time effective to thereby form the desired lithium transition metal oxide.
Suitable lithium _~Lo~ln~s would be selected from the salts, oY~s or hyd~ of lithium.
The transition metal compounds would be selected from the O~ C of cobalt, nickel, manganese, vanadium, iron, titanium or chromium, or mixtures thereof. Preferably, the transition metal l_ _ u,-ds would be selected from the oxides of cobalt, n~ ~1 or manganese or mixtures thereof. Alternatively, suitable transition metal ~ , unds would be selected from the hydroxides, carbonates or salts of cobalt, nickel, manganese, vanadium or chromium or mixtures thereof.
The additives, which may be utilized optionally, are believed to ~ e formation of the liquid phase and extend the t- ,-~ature range of the molten phase of the lithium compound. The most effective additives have been found to be Al ~1 ~ metal ~ unds, part~ ~ly potassium or sodium hydroxide or mixtures thereof, which have very wide ranging molten t ~eratures ext~n~ng from 300 to above 1200~C. The preferred additive is potassium l-yd ~ide.
The reaction must be undertaken in an atmosphere which is L~ on~l to either ~V--~l L the transition metal l_ , ~nd to an oxide and/or to maintain the transition metal oxide in the correct oxidation state namely the same oxidation state as the tran~ition metal in the final product. Thus, the reaction atmosphere may ~o...~ lse an inert atmosphere, a r~l-c~ng SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 atmosphere or an ~Y~17~ng atmosphere ~ep~n~n~ upon the nature of the reactants.
As will be evident to one Ck~ 1 in the art, it is possible to produce the lithium transition metal oxide powders of predetermined particle size and controlled mic~o~ cture by controll~ n~ reaction time and temperature during the heating stage. The temperature ranges would extend from 200~C to 1200~C and the residence times from lh to 72h. The elevated t- ,~ature controls the structure and is n~c~s~y for the reaction to take place, whereas the residence times determine the resultant particle size and surface area.
The desired structure defines the reaction temperature and at this temperature the lithium ~ und and/or additive must be optimized whereby the lithium compound and molten medium provide the desired envi ~ t for growing the partlcl~q with the desired mi~o~L-~L~.e.
The reaction m~-han~sm postulated for the synthesis of lithium transition metal oxides was extrapolated from the discovery, that in the synth~s of lithium cobaltic ~ioY~ from cobalt (III) oxide and an ~Yc~s~ of lithium carbonate, the lithium carbonate is ret~ n~ in the molten state during the reaction. The reaction takes place above 720~C and in a static, neutral or non-oY~d~ 7i n~ atmosphere, with the lithium carbonate undergoing partial d~c_ ~osition to form carbon dioxide which is retained in the static atmosphere. The reaction thus G~ in the molten state, under optimum thermodynamic conditions. Without being bound by same, the molten phase is believed to exist, under the reaction conditions, as a coating on the solid transition metal oxide part~le~.
The ~ tion of the atmosphere should also be ad~usted to control the th~ ~ _ s~tion of the lithium ~ _~und. For ~ - ,le, if lithium carbonate SUBSTITUTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA~G10~98 is used, sufficient carbon dioxide should be present in the atmosphere to retard its thermal ~omro~ition at reaction t~ -~ature.
As a ~ ~cial process, the process of the invention has several advantages over the methods of the prior art. It has the advantage that the preparation of lithium transition metai oY~ can be ~z~ h~-l in a single high t- -~ature heating step, in contrast to the prior art methods which require multiple firings under CAl ~-~ n~tion conditions. Since the reaction occurs in a molten phase, instead of as a solid state reaction, it has faster kinetics, thereby producing a more uniform, h~ _el,eous and repro~-~ihle powder product with controllable particle size and growth. Therefore, this improved process is more A ~hle to large scale ~ ~;ial production.
Advantageously, the produced lithium transition metal oxide powders exhibit low surface area, a narrow particle size distribution, and high ch~ ~c purity.
Description of the Drawings The method of the invention will now be described with reference to the A- ,-nying drawings, in which:
Figure 1 is a y~elAl ~ 7~ process flowsheet for the production of lithiated transition metal ~o~
powders by the process of the present invention;
Figure 2 is a pho~ oy~aph illustrating lithium cobalt ~oY~ powder prepared by the process of the present invention;
Figure 3 is a photo~i~oy aph illustrating lithium n~ ok~l dioxide powder prepared by the process of the present invention:
Figure 4 is a histogram illustrating size distribution ranges for lithium cobalt dioxide SUBSTITUTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA~6~198 powder prepared from cobaltic oxide by the process of the present invention;
Figure 5 is a histogram illustrating size distribution ranges for lithium cobalt dioxide powder prepared from cobaltous carbonate by the process of the present invention:
Figure 6 shows the first charge and ~cc~ge of the ele~L~ h~ ; C~ 1 cell wherein the cathode was prepared of LiNiO2 powder prepared by the process of the invention; and Figure 7 depicts part of the life cycle of the cell of Figure 6, with voltages between 4.15 and 3.0 volts.
Description of the Preferred Fmb~ -nt A finely divided lithium ~G...~ound and one or more transition metal compounds are well ~ Y~ in st~h~- -L~c quantities, or in the case of the lithium compound in an amount slightly greater than stoichiometrically reguired. The mixing step is critical hC~c~:~uc~ a poorly mixed reactant powder could lead to a product having a particle size distribution range which is too broad b~C~l~c~ the rate of particle ~wLh is ~re~nt upon the ~sr~sion of the lithium salt.
Suitable lithium _ _~unds are those effective upon heating to exist in the molten phase with no, or only partial ~s , -~tion thereof, t~k~ n~ place under the reaction con~ ~ tions. Such compounds would be selected from the salts, oxides or hydroxides of lithium. The preferred lithium ~_ , unds are lithium hydroxide for ~ ratures below and about 750~C and lithium carbonates for reaction temperatures above A
750~C. If LiOH is used, thermal ~ - ition of the LiOH can be controlled without ~on~ _ i tant inhibition SUBSTITUTE Sl ~ (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA9~/J~1~3 of the lithiation reaction, by doping the atmosphere with steam or water vapour.
The transition metal compounds would be selected from the oxides of cobalt, n~ ~k~l, manganese, vanadium, iron, titanium, chromium, or mixtures thereof.
Preferably, the transition metal ~- , unds would be selected from cobalt, ~ckDl or manganese or mixtures thereof. Alternatively, suitable transition metal compounds would be selected from the hydroxides, carbonates or salts of cobalt, nickel, manganese, vanadium or chromium or mixtures thereof. These latter transition metal ~_ , unds must be convertable to their respective oxides in-situ. It is most advantageous i$
the oxide added or produced in-situ is in the same oxidation state as the final product, so that the reaction can be carried out with the ~ ni of air or oxygen, and the stAh~ 1~ 7~tion of the molten lithium salt can then be effected by co~Al~cting the reaction in an enclosed atmosphere.
An additive comprising an alkali metal compound may be added to the reaction mixture.
Preferably, the additive would be selected from NaOH or KOH. The amount of additive used would range from 0.1 to 50 molar % based on the transition metal content. In the case of the synthesis of lithium cobalt ~ioY~ ~D
using the pathways described herein, it is not necDcc~y to add an additive in order to obtain a satisfactory product. However, in the production of lithium ni ~.kDl oxide or lithium manganese oxide the prDCDncD of an additive has been found to assist in opt~ 1 7~ ~g the kinetics of the reaction and st~h~l~ 7'1 ng the thermal o~tion of the lithium ~...~o~nd.
The. mixture is intro~ncD~ into a furnace where it is heated to ~ _~ atures ranging from 200 to 1200~C
for periods of time ranging from lh to 72h. The SU~S 111 UTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/'~5062 PCT/CA~G~ 0133 reaction atmosphere, as stated earlier herein, must be functional to either convert the transition metal ~_ _und to its oxide and/or to maintain the transition metal oxide in the desired oxidation state, namely that of the transition metal in the final product. Thus the atmosphere may be either inert, oY~ 7~ng or r~dl~oing and is readily de~e~ ~ef1 by one ~k~11e~ in the art.
The product and process of the i-.venLion will now be described with reffs~e..ce to the following non-limitative examples.
The synthesis of lithium cobaltic ~oY~ to form powders suitable for use in lithium ion battery ~y~ . Having reference to the flowsheet of Figure l, finely divided lithium carbonate and cobalt(III) oxide in sto~ ~h~ tric, or slightly greater than stoichiometric amounts, are ~ YeA in bl~n~ ~ ng step l. The cobalt (III) oxide may be synth~s~ 7e~ by various routes as will be described hereinafter. The mixture is inL~ c~1 into a furnace where it i8 heated in cAlç~nAtion step 2 to a ~ ,- ature in the range of about 750 to 900~C in a static, neutral or non-or~ n~ atmosphere, for a period of time of about 6 h to 72 h. Following ~Alc~n~tion, the sintered lithium cobaltic dioxide product is pulverized to break up agglomerates using a h; - ~ 11 or ball mill in ~ n~
step 3. An optional water wash ~ollows, wA ch~ n~ step 4, he~A~s~ advd,.~ageously it has been determined that water appears to l"- -ve most of the soluble impurities such as sulphur and sodium, as well as unreacted ~Yc~-cc lithium carbonate.
It is believed that by using an essentially pure cobaltic oxide powder and lithium carbonate the process of the invention yields lithium cobaltic having a constant particle size and surface area, SIJ~ JTE SHEET (RULE 26) CA 02227~34 1998-01-21 irrespective of the shape and size of the reaction vessel. The physical properties of the powder can be simply controlled by the furnace temperature and residence time. Additionally, if an ~Yc~sc of lithium carbonate is utilized (i.e. a 5 to 10% stoi~h~ stric ~Y~cc over cobalt), then a lithium to cobalt atomic ratio of 1:1 in the powder product is obtA~ ne~ .
The cobalt (III) oxide can be prepared by several routes, namely from cobaltic h~Y i ne sulphate solution or cobaltic pentammine sulphate solution, by precipitation with sodium or potassium h~dl~xide, or from a soluble cobalt(II) salt by oxidation with a strong oxidizing agent, or from cobalt carbonate by high temperature oxidation in air, or can alternatively be obt~ineA from ~ -~cial suppliers.
Preparation of Cobaltic Oxide from Cobaltic ~ ne Sulphate 72 g of sodium hydroxide (ex 8DH Ltd), ~ccOlved in one litre of water, was slowly added to a 3L solution which contAi n~ 180 g of cobaltic heYr ~ne sulphate (ex Sherritt Inc), at 90~C. The mixture was stirred and heated to its ho~ 1 ~ng point, for 30 minutes, to drive off the copro~ A, The slurry was cooled and the s~ .atant liquor decanted off. The black precipitate was wAche~ twice with a similar quantity of pure water, before it was filtered and washed twice to 1- ~v~ soluble ~ , ~ties. It was then dried in an oven at 120~C for about 24 hours. The product analyzed as hydrated cobaltic oxide with 61.1%
w/w cobalt. The above procedure was repeated twice more and the product analyzed at 61.5 and 61.3% w/w cobalt.
SUBSTITUTE SHEET (RULE 26) CA 02227534 l998-0l-2l 2 PCT/CA9~/~S~3 E~MPLE 3 Preparation of Cobaltic oxide from Cobaltous Sulphate 2.24 kg of . ~um sulphate was ~i-Q~olved in 20 litre_ of aqueous cobaltou~ lp~te solution, with a cobalt ,v ~- tration of 100 g/L at 50~C. 3.46 kg of r _ ~ ~ ( as 29% aqueous : - ~) was added slowly, until any of the in~ ~te precipitate had r~solved.
The resultant cobaltous y~ sulphate solution was oYid~ed to cobaltic y~ i~ sulphate by the addition of l.Z8 kg of l~ydL~y~ peroxide (as a 30% solution in water).
The cobaltic pentammine sulphate solution was heated to 90~C and 4.2 L aqueous sodium hydroxide (240 g/L) added at a rate of 300 ml/min. The mixture wa_ stirred during this addition and finally heated to its boiling point to drive off any ~ ~g : ~. The ~y~,..atant liquor was decanted from the settled slurry.
Any soluble 1 _~.ities were ,~ _~ed from the black precipitate by twice repulping it with pure water, foll~ ed ~y filtration and ~ Qh~g the filtrate twice more with pure water. After drying the black solid in an oven at 120~C for about 24 hours, it analyzed as hydrated cobaltic oxide with 61.1% w/w cobalt.
Conversion of Cobaltic Oxide into Lithium Cobaltic Dioxide over Different Time Periods 1.3 kg of dried cobaltic oxide, y.e~a.el as in Example 3 above, and 0.9 kg of lithium -~ bo -te (ex Cyprus Foote) were mixed ~ her in a V hl ~ for 4 hours. 300 g aliquots of the mixture were lo~ded into one litre CN1000 alumina c~ihl~Q (ex Coors). Each crucible was heated in a NEY box furnace at 900~C.
Individual crucibles were ,~ ~e-~ after seven different time periods (1, 3, 6, 12, 24, 36 and 48 hours). The resultant products were broken up into p~ Q, the size SlJts~ 1 UTE SHEET (RULE 26) -CA 02227~34 1998-01-21 W 097/05062 PCT/CA9G~ 15&
of a pea, in a mortar and pestle, and fed to a h- ill, for light deaggl~ ation, and the powder r~q5 ' Ll~o~yl~ a 400 mesh screen. The minus 400 mesh fraction was analyzed; the results are given in Table I. The particle size of the ~ increases as the r~ time of the reactant mixture in the furnace is increased, ;~ting that the particles grow in situ.
The surface area of the ~ ~d~L decreased to a constant value as the particle size increases.
TABLE I
Time (hrs) D 50% (um) Surf2ace Area m /g 1 3.9 1.73 3 5.2 1.15 6 7.2 0.77 12 8.8 0.45 24 10.9 0.35 36 12.4 0.36 48 15.2 0.38 Co--ve ~ion of Cobalt Oxide into Lithium Cobaltic D~AJX~
at Different Te~..~atures A blend of dried cobaltic oxide and lithium carbonate was mixed as in Example 4. 300 g aliquots were loaded into one litre CN 1000 alumina crucibles and placed in the NEY furnace at different temperatures (800, 900 and 1000~C) for 36 hours. The resultant products were fed to a hammermill, for light deagglomeration, and segregated on a 400 mesh screen.
The minus 400 mesh powder was analyzed and the results, given in Table II, show that the growth of the particles increases as the furn~ing ~~ ,A~ature increases.
S~J~S 111 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 W 097/05062 PCT/CA~'C~58 TABLE II
Temp (~C)D 50% (um) Surf~ce Area (m /g) 800 3.6 0.98 900 12.4 0.36 1000 24.1 0.44 Comparison of the Synth~-s of Lithium Cobaltic Dioxide from Cobaltic Oxide and Cobaltous Carbonate Powders of either cobaltic oxide (prepared as in Example 2 above) or cobaltous carbonate (ex Aldrich Chemical) were blended with lithium carbonate, in a V
blender, as in Example 4, and various amounts were charged to various sizes and -shApe~ of alumina crucible.
The mixtures were each reacted in a NEY furnace for 36 hours at 900~C, and then deaggl~ ated as in ~Y- _l~ 4.
The analytical results are displayed as his~oy~ in Figures 4 and 5. From Figure 4, it can be seen that the furnaced product from cobaltic oxide has particles with a similar median and size range irrespective of the crucible size, shape or lo~dln~. Figure 5, hcs~v~r, shows that dioxide made from cobaltous carbonate is sensitive to crucible size, shape and lo~ . Two additional runs (52A and 66 in Figure 5) were carried out in which the cobaltous carbonate was first ~ecc _-~cd before it could react with lithium carbonate, i.e. the furnace t~mro~ature was first held at 400~C for 6 hours (to ~ ~s~ the carbonate to cobalt oxide) and then the ~ _ ature was raised to 900~C to _ _l~te the reaction of the resultant oxide with lithium carbonate.
The analytical results show that crl~c1hle shape and size do not now appear to affect the particle size of the lithium cobaltic ~1ox~
SU~ 111 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97105062 PCT/CA~G
E~U~MPLE 7 The effect of Excess Lithium Carbonate on the Preparation of Lithium Cobaltic Dioxide.
Mixtures of cobaltic oxide and lithium carbonate were made up as in ~Y~ 1~ 4, in which the lithium carbonate content was set at different stoichiometric ~.D~C~ ( -20%, 0%, 20%, 50% and 100~).
Equal quantities of each mixture were treated in the furnace as before (900~C for 36 hours). The products were then analyzed, and the results are given in Table III. It can be seen that the largest particle sizes are achieved when an eYc~cc of lithium carbonate is present, indicating that part~ Ate growth is assisted by the presence of molten lithium carbonate.
TABLE III
Target (FY~.~CC ~) D 50% (um) Surface Area (m2/g) -20 2.6 1.99 ~5 12.4 0.36 ~20 14.2 0.41 l50 14.2 0.46 +100 11.3 0.63 The Effect of C- ~~tion on the Preparation of Lithium Cobaltic Dioxide Cobaltic oxide and lithium carbonate were hl~n~, as in F ~ _le 4, and the resultant powder was sub~ected to _ _~-tion by pl~ ng it in a 2 cm diameter mold and ~d~ n~ 5 tons of pressure to the piston. The 1 n long ~ t had a density of 1.8 g/cc ~ ~~ed to 0.5 g/cc for the original powder bl~n~e~. Several comr~cts were pl~c~ in a crucible and placed in a NEY
furnace at 900~C for two different time periods (12 and 24 hours). The products were analyzed, and the results SU~S 111 UTE SHEET (RULE 26) CA 02227~34 l998-0l-2l are given in Table IV. It can be seen that the rate of growth of the lithium cobaltic dioxide particles greatly increased when compared to the product from the original powder. In fact, the compacted product obt~in~ after 12 hours is similar to that obt~ from the ~omr~ted powder in 36 hours (Ref. rrable 1).
TABLE IV
Lithium Cobaltic Dioxide made from C~ ted Powder 'rime (hrs) D 50% -400 mesh (um) 12 13.3 24 13.9 The synthesis of lithium nickel ~ox~e to form powders suitable for use in lithium ion battery ~y~te Having reference to the flowsheet of Figure 1, lithine, LiOH.H2O, nickel hydroxide, and potassium and/or sodium hydroxide are ground together and are well mixed in stoichiometric amounts in bl~n~3~ ng step 1. The mixture is introduced to a furnace where it is heated (step 2) in an oxygen ContA ining atmosphere to a temperature in the range of 500 to 1000~C, for a period of time of about 10 to 50 hours. Following caiclnation, the sintered lithium nickel dioxide is optionally pulverized to break up aggll - ates using a hammermill or ball mill (step 3). A water wash 4 is carried out followed by a final oven drying step 5, and c~ ccification 6 to ~e~;ov2r the lithium n~--k~ x1 powder product.
Preparation of Lithiated Nickel Dioxide with and without Potassium Hydroxide 46g of lithine, LiOH.H2O, 93 g of n~Ck~l hydroxide and 7.3 g of potassium hydroxide (85 % KOH) were ground SIJ~3 111 UTE SHEET (RULE 26) -CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA9~ 198 and mixed together in a mortar and a pestle for about 20 minutes. The 1.1:1.0:0.1 (Li:Ni:K) mole ratio blend was heated in a furnace at 800~C for 20 hours in air, then was removed from the furnace, pulverized, washed with distilled water and dried in an oven at 150~C for 5 hours. The resultant product, which r~ ee~ through a 400 mesh sieve, analyzed, by an average particle size of 11.5 microns, and BET (Brl~n~e~-Emmett-Teller) surface area of 0.74m2/g. After reheating at 600~C for 1 hour, the surface area was reduced to 0.32 m2/g. ~ ic~l analysis i n~ ir~ted that the potassium content was 0.002 ~ by weight, that is that the potassium _ ,7unds can be washed out almost completely and that the KOH does not add impurity ph~Q~s or ~...~o~nds to the final LiNiO2 product.
For _ ,~~ison, a -e~con~ Q~mrl~ of LiNiO2 was prepared as described above, but without the inclusion of the potassium hydl~xide. X-ray diffraction ~ n~ c~ted that LiNiO2 had been obt~; n~, but an SEM mi~l~y a~h showed that the average particle was about 3.0 microns which is significantly smaller than the particles obtained in the presence of KOH, under the same conditions.
For further comparison, a thlrd sample of LiNiO2 was prepared as above, but without the inclusion of the potassium hydroxide and with a larger ~YC~QS of lithium l.ydl~ide. The starting material corresp~e~
to Li:Ni mole ratio of 1.2:1.0, that is a 20% ~cc lithium hydroxide, compared to 10% excess lithium hydroxide in the previous two samples. After heating the materials at 800~C for 20 hours, it was found that the particle size was also about 3.0 microns, clearly trating that the pr~e~nc~ of potassium hydl~ide is n~ee~y to increase the growth rate of LiNiO2 particles.
SU~:i 1 1 1 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 W O 97/05062 PCT/CA~ 198 Preparation and Electrochemical Cell Perfor~nc~ of Lithiated Nickel Dioxide with Potassium hydroxide at a Lower Temperature 92g of lithium hydroxide, 185g of nickel hydroxide and 14.7 of potassium hyd.~xide (85% KOH) were ground together with a mortar and a pestle for about 20 minutes, the blend heated at 700~C for 20 hours in air, and the product pulverized then washed with water, and finally dried in an oven at 150~C. The product which p~c-s~ through a 400 mesh sieve, analyzed as a single phase of LiNiO2, with lattice constants a=2.880 A and b=14.206 A, which agree very well with the reference data (Journal of Power Sources 54 (1995) 109-114). The sample particle sizes, as viewed by SEM were between 1 and 3 microns, and an average particle size, as ~ ~ed by MicrotracTM (light scattering method), of 2.5 microns. t~h~ analysis gave lithium, n l -~k~l and potassium contents as 7.18% and 59.91% and 0.002% by weight respectively; the Lheo.etical values for Li and Ni for LiNiO2 are 7.11% and 60.11%. When impurities due to the reactants are taken into a~o~--L, the fo. ~1 A for the product wa~ postulated to be Lil_XNil+xO2 with-0.02<x<0.02. The value of x in Lil_XNil+XO2 made by other ~.~v~.~tional methods is usually x>0.02. This in~in~tes that a better guality product is obt~ne~ with potassium h~d-~ide in the reaction mixture, probably because the potassium ~ es better distributlon of the lithium within the melt at reaction ~ ture.
An electroche ~cal cell, with a cathode, separator, anode and an electrolyte wa~ ~-- hl ed in which the cathode was made of the LiNiO2 powder from above, mixed to a paste, with 9% by weight of Super S
carbon black and 1~ by weight EPDM (ethylene propylene diene terpolymer), and spread on aluminium foil before SUBSTITUTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA96/'~158 being allowed to dry; the paste coverage was typ~c~lly 20 mg/cm2 and cathode area was 1.2 x 1.2 cm2. The electrolyte was 1 M lithium perchlorate, LiCl04 in propylene carbonate. Lithium metal was used for the anode and Isotactic Poly~lo~ylene (Celgard 2500TM) as the separator. Cell hardware was st~i nl q8~ steel with an aluminium substrate, sealed with an O-ring and stack pressure provided by a spring. Lithium foil was att~he~ to the stainless steel hardware and the cathode att~ch~ to the al~ ~nl substrate. Charge ~ ~--L was ad~usted to correspond to x-0.5 Li deintercalation in Li1-_XNil+XO2 during a charge of 20 hours, and the discharge current ad~usted to correspond to x~0.5 Li intercalation in 10 hours. The charge voltage was up to 4.15 V and the ~ h~ge voltage down to 3.0 V. Figure 6 shows the first charge and ~ch~ge curve of the cell using LiNiO2 as cathode materials. The first charge ~-~r~ ty is seen to be 200 mAh/g and the first ~ h~ge ~p~c~ty 145 mAh/g. The cycle life is shown in Figure 7 with voltages between 4.15V and 3.0 V. The fade rates are very low, and significantly less than materials made by prior art at this working voltage range and at this ~r~ ty.
Example 12 Preparation of Lithiated Nickel Dioxide with Sodium ~xide A sample of LiNiO2 was made in the same way as the first sample in Example 9, with sodium hyd ~ide in place of the potassium hydroxide: that is, 46g of lithine, LiOH.H2O, 93 g of n~k~l l.ydlo~ide and 4.5 g sodium hydroxide (97% NaOH) were ground and ~Ye~
together in a mortar and a pestle for about 20 minutes.
The 1.1:1.0:0.1 (Li:Ni:Na) mole ratio blend was heated in a furnace at 800~C for 20 hours in air, then was removed from the furnace, pulverized, w~h~ with SlJ~S 1 1 1 UTE SHEET (RULE 26) CA 02227~34 1998-01-21 2~
distilled water and dried in an oven at 150~C for 5 hours. The resultant product, which pA~C~ through a 400 mesh sieve, analyzed by X-ray diffraction as pure single phase of LiNiO2 with a low sodium content (less than 5% of the original was left). The X-ray diffraction pattern of the LiNiO2 product agreed with the stAn~d data, and no impurity phase was ob~elved.
In conclusion, sodium hydroxide can be used instead of potassium hyd ~ide ~or this preparation.
F---, le 13 Preparation of Lithiated Cobalt D~Y~ with and without Potassium Hydroxide The effect of the potassium hydroxide on the growth rate of particles during the syn~h~C~ of lithium cobalt dioxide, LiCoO2 was investigated. Firstly, LiCoO2 was prepared by the same method as the first ~r _ le of LiNiO2 was prepared in F le 10, that is, 46g of lithine, LiOH.H20, 97g of cobalt oxide (contA~nin~ 60~ cobalt by weight) and 7.3 g potassium hydroxide (85 % ROH~ were ground and mixed ~~y~Lher in a mortar and pestle for about 20 minutes. The 1.1:1.0:0.1 (Li:Co:K) mole ratio blend was heated in a furnace at 800~C for 20 hours in air, then was l~ v~d from the furnace, pulverized, washed with distilled water and dried in an oven at 150~C for 5 hours. The resultant product, which passed through a 400 mesh sieve, analyzed by X-ray diffraction as a very pure single phase of LiCoO2. The peak positions agree well with the st~A~d materials, with lattice constants a~2.819~0.001 A and b=14.07_0.01A. Mi~ ~L~acTM analysis show an average particle size of 8.5 microns. ~h~ ~ CAl analysis gave lithium and cobalt of 7.34% and 59.72% by weight, t very close to 1:1 mole ratio, with a very low potassium content of 0.031%, showing that the potassium ~ nds SUBSTITUTE SHEET (RULE 26) CA 02227~34 l998-0l-2l W O 97/05062 PCT/CA96,'~19 can be easily washed away after the calcination reaction.
For l~ ~ison, a second C~mrl~ of LiCoO2 was made, as above, but without the addition of the potassium hydroxide, that is, 46g of lithine, LiOH.H20 and 97g of cobalt oxide (cont~ n~ ng 60.5% cobalt by weight) were ground and mixed together in a mortar and a pestle for about 20 minutes. The 1.1:1.0 (Li:Co) mole ratio blend was heated in a furnace at 800~C for 20 hours in alr, then was removed from the furnace, pulverized, washed with dist1ll~ water and dried in an oven at 150~C for 5 hours. The resultant product, which passed through a 400 mesh sieve, analyzed by X-ray diffraction as a very pure single phase of ~iCoO2 with lattice constants calculated as a=2.819+0.001 A and b=14.07+0.01A. Chemical analysis shows lithium and cobalt ~on~e..ts are 7.58% and 59.17%, re~e~L~vely, that is the lithium ratio is slightly higher than stoichiometric requirement. However, the average particle size was only 4.9 microns, 1n~ ting that part~ of LiCoO2 prepared with the 10% potassium hydloxide in the blend grow to be Al L twice as large as those obt~ n~ without potassium hyd oxlde, under the same conditions.
Example 14 Dea~qll ation of the Product Particles by W~Sh~ n~ or Two samples of lithium nickel ~1oY~ were prepared by a similar method to that outl~ in FYr 1 ~
ll, except that larger crucibles were used, each containing 500 g of the reactant mixture. The calcination was carried out at two different temperatures, 750 and 800~C, with an atmosphere of o~yy~-- present in the furnace at the lower t , ~ature, and air instead of o~yye-- at the h~ghD~ t- ,e~ature.
S~J~ 111 ~JTE SHEET (RULE 26) 2~
Two examples of the product ~rom each calcination were treated as ~ollows. One part was deagglomerated by lightly grinding in a ceramic ball mill, and the other part was deagglomerated by simply washing it with water. The median particle sizes of the resultant powders are given in Table V for a comparison of median particle size in um of calcined product after deagglomeration of a mill or with a simple water wash.
Table V
Median Particle ~ize (um) 750~C with ~2 800~C with air Water Wash9.7 8.0 Milling 7.4 6.3 Both treatments lead to approximately the same particle size in the ~inal product, so there is a process choice in the post treat~ent o~ the calcined product to convert it to powder: deagglomeration in a mill, or washing with water.
Figure 2 is a photograph of the particles made when lithium cobalt dioxide (as prepared in Example 4, with 36 h in the ~urnace) is milled to deagglomerate the product particles.
The micrograph shows particles with smooth faceted sur~aces indicating that the particles comprise one crystal or an agglomerate of a small number of crystals with an average diameter in the range o~ 1 to 25 microns as evidenced by the typical distance between and relative scarcity of grain boundaries intersecting the particle surfaces. This characteristic is in contrast to that of particles of lithium nickel dioxide produced by the methods described in the prior art which comprise a multi-crystal agglomerate AMENDED S~EET
, ~ CA 02227~34 1998-01-21 ~, , with a cons~ituent crystal size cf less than 1 micron consequently having a large number cf grain boundaries intersecting the particle surfaces and giving the particles a rough knobbly appearance. Figure 3 is a photograph of the particles which result from a water wash treatment of lithium nickel dioxide, as made and treated by the procedure described in this example. These results clearly demonstrate that the particles made by the process of this invention grow in a single step, and that their unique size and structure do not result from the comminuti~n o~ a large calcined mass.
It will be understood, of course, that other embodiments and examples o~ the invention will be readily apparent to a person skilled in the art, the scope and purview of the invention being de~ined in the appended claims.
AMENDED SltEET
Claims (18)
1. A process for the synthesis of lithium transition metal oxide powders having a predetermined particle size with a median diameter in the range of about 2 microns to about 25 microns and a surface area in the range of about 0.1 to about 1 square meter per gram which comprises: reacting one or more transition metal compounds with a salt, oxide or hydroxide of lithium. said lithium compound being present in a molten phase during and following said reaction at a temperature in the range of about 500°C to about 1000°C for a time of at least 1 hour, and optionally, with an additive selected from potassium hydroxide, sodium hydroxide or mixtures thereof to increase the effective molten phase temperature range of said lithium compound in a surrounding atmosphere to inhibit the thermal decomposition of the lithium compound remaining following the reaction within said temperature range and to convert and maintain the transition metal compound in an oxidation state which corresponds to the oxidation state of the transition metal ions in the product.
2. A process as set forth in claim 1 wherein said lithium compound comprises lithium hydroxide or lithium carbonate.
3. A process as set forth in claim 2 wherein said transition metal compound is selected from a salt, oxide, or hydroxide of cobalt, nickel, vanadium, iron, titanium or chromium or mixtures thereof.
4. A process as set forth in claim 2 wherein said transition metal compound is selected from the oxides or hydroxides of cobalt, nickel, or mixtures thereof.
5. The process as set forth in claim 1 wherein said lithium compound comprises lithium hydroxide or carbonate, said transition metal compound comprises a salt, oxide or hydroxide of cobalt, nickel, iron, vanadium, titanium or chromium or a mixture thereof, and said additive is potassium hydroxide or sodium hydroxide.
6. The process as set forth in claim 1 wherein said lithium compound comprises lithium hydroxide or lithium carbonate, said transition metal compound comprises an oxide or hydroxide of cobalt, and said additive is potassium hydroxide.
7. The process as set forth in claim 1 wherein said lithium compound comprises lithium hydroxide or lithium carbonate, said transition metal compound comprises an oxide or hydroxide of nickel, and said additive is potassium hydroxide.
8. The process as set forth in claim 1 wherein said lithium compound comprises lithium hydroxide and water is added to the atmosphere thereabove, to thereby control the thermal decomposition of said molten lithium compound.
9. The process as set forth in claim 3 wherein said lithium compound comprises lithium hydroxide and water is added to the atmosphere thereabove, to thereby control the thermal decomposition of said molten lithium compound.
10. The process as set forth in claim 5 wherein said lithium compound comprises lithium hydroxide and water is added to the atmosphere thereabove, to thereby control the thermal decomposition of said molten lithium compound.
11. The process as set forth in claim 1 wherein said lithium compound comprises lithium carbonate and carbon dioxide is added to the atmosphere thereabove to thereby control thermal decomposition of the lithium compound.
12. The process as set forth in claim 3 wherein said lithium compound comprises lithium carbonate and carbon dioxide is added to the atmosphere thereabove to thereby control thermal decomposition of the lithium compound.
13. The process as set forth in claim 5 wherein said lithium compound comprises lithium carbonate and carbon dioxide is added to the atmosphere thereabove to thereby control thermal decomposition of the lithium compound.
14. Lithium transition metal oxide powder forming discrete particles and having a median particle size ranging from about 1 to 25 microns and a surface area ranging from about 5 to 0.1m2/g.
15. Lithium cobalt oxide powder forming discrete particles and having a median particle size ranging from about 1 to 25 microns and a surface area ranging from about 5 to 0.1m2/g.
16. Lithium nickel oxide powder forming discrete particles and having a median particle size ranging from about 1 to 25 microns and a surface area ranging from about 5 to 0.1m2/g.
17. A lithium nickel dioxide powder having an average crystal size ranging between 1 to 25 microns and an agglomerate particle size ranging from 2 to 50 microns.
18. A lithium nickel cobalt dioxide powder having an average crystal size ranging between 1 to 25 microns and an agglomerate particle size ranging from 2 to 50 microns.
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| EP0798797B1 (en) * | 1996-03-26 | 2001-09-12 | Sharp Kabushiki Kaisha | Process for preparing positive electrode active materials, and nonaqueous secondary battery utilizing the same |
| US5955051A (en) * | 1996-08-02 | 1999-09-21 | Westaim Technologies Inc. | Synthesis of lithium nickel cobalt dioxide |
| JP4691228B2 (en) * | 1999-11-02 | 2011-06-01 | Ａｇｃセイミケミカル株式会社 | Method for producing lithium-manganese composite oxide for non-aqueous lithium secondary battery |
| JP2001273898A (en) * | 2000-01-20 | 2001-10-05 | Japan Storage Battery Co Ltd | Positive active material for nonaqueous electrolyte secondary battery, method of manufacturing same, and nonaqueous electrolyte secondary battery using the active material |
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| JP4650648B2 (en) * | 2000-04-20 | 2011-03-16 | 株式会社豊田中央研究所 | Method for producing lithium manganese composite oxide |
| US7018607B2 (en) * | 2003-06-25 | 2006-03-28 | General Motors Corporation | Cathode material for lithium battery |
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| WO2017198506A1 (en) * | 2016-05-18 | 2017-11-23 | Basf Se | Open vessels and their use |
| KR101939484B1 (en) * | 2017-08-11 | 2019-01-16 | 한양대학교 에리카산학협력단 | Transition metal compound, method of fabricating of the same, and electrode active material for lithium secondary battery comprising the same |
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| JP2022507056A (en) * | 2018-11-09 | 2022-01-18 | ビーエーエスエフ コーポレーション | Process for Producing Lithiumized Transition Metal Oxides |
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| CN111172743B (en) * | 2020-01-16 | 2021-10-19 | 浙江大学 | Method for rapidly preparing composite metal oxide nano film material at low temperature |
| JPWO2022196762A1 (en) * | 2021-03-19 | 2022-09-22 | ||
| JP2023004695A (en) * | 2021-06-28 | 2023-01-17 | 住友化学株式会社 | Method for producing lithium metal complex oxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2087858B (en) * | 1980-11-25 | 1984-08-22 | Mizushima Koichi | Reduction of so2 in polluted gases high surface area conductors |
| JP3135545B2 (en) * | 1990-01-23 | 2001-02-19 | 日立マクセル株式会社 | Lithium secondary battery and method of manufacturing the same |
| JPH04115459A (en) * | 1990-09-05 | 1992-04-16 | Mitsubishi Electric Corp | Preparation of positive electrode material for lithium battery |
-
1996
- 1996-07-23 WO PCT/CA1996/000498 patent/WO1997005062A1/en not_active Application Discontinuation
- 1996-07-23 CN CN96195990A patent/CN1192193A/en active Pending
- 1996-07-23 JP JP9502326A patent/JPH11510467A/en active Pending
- 1996-07-23 EP EP96946139A patent/EP0843648A1/en not_active Withdrawn
- 1996-07-23 AU AU64106/96A patent/AU6410696A/en not_active Abandoned
- 1996-07-23 CA CA002227534A patent/CA2227534A1/en not_active Abandoned
- 1996-07-23 KR KR1019980700751A patent/KR19990036085A/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7353868B2 (en) | 2004-02-24 | 2008-04-08 | 789047 Alberta Ltd. | Wireline coupler |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0843648A1 (en) | 1998-05-27 |
| CN1192193A (en) | 1998-09-02 |
| WO1997005062A1 (en) | 1997-02-13 |
| KR19990036085A (en) | 1999-05-25 |
| AU6410696A (en) | 1997-02-26 |
| JPH11510467A (en) | 1999-09-14 |
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