Title of Invention

A METHOD OF PREPARATION OF LITHIUM-CONTAINING MATERIALS

Abstract ABSTRACT IN/PCT/2002/01089/CHE "A method of preparation of lithium-containing materials" This invention relates to a method of preparation of lithium containing materials which, upon electrochemical interaction, release lithium ions, and are capable of reversibly cycling lithium ions. The invention provides a rechargeable lithium battery which comprises an electrode formed from the novel lithium-mixed metal materials. Methods for making the novel lithium-mixed metal materials and methods for using such lithium-mixed metal materials in electrochemical cells are also provided. The lithium-mixed metal materials comprise lithium and at least one other metal besides lithium.
Full Text

PREPARATION OF LITHII3M-C0NTAINING MAXERIALS
Field of the Invention
This invention relates, to improved materials usable as electrode active materials and to their preparation.
Background of the Invention
Lithium batteries are prepared from one or more lithium electrochemical cells containing
electrochemically active (electroactive) materials. Such cells typically include an anode (negative electrode), a cathode (positive electrode), and an electrolyte interposed between spaced apart positive and negative electrodes. Batteries with anodes of metallic lithium and containing metal chalcogenide cathode active material are known. The electrolyte typically comprises a salt of lithium dissolved in one or more solvents., typically nonac[ueous (aprotic) organic solvents. Other electrolytes are solid electrolytes typically called polymeric matrixes that contain an ionic conductive medium, typically a metallic powder or salt, in combination with a polymer that itself may be ionically conductive which is electrically insulating. By convention, during discharge of the cell, the negative electrode of the cell is defined as the anode. Cells having a metallic lithium anode and metal chalcogenide cathode are charged in an initial condition. During discharge, lithium ions from the metallic anode pass through the liquid electrolyte to the electrochemical

active (electroactive) material of the cathode whereupon they release electrical energy to an external circuit.
It has recently been suggested to replace the lithium metal anode with an insertion anode, such ag a lithium metal chalcogenide or lithium metal oxide. Carbon anodes, such as coke and graphite, are also insertion materials. Such negative electrodes are used with lithium- containing insertion cathodes, in order to form an electroactiye couple in a cell. Such cells, in an initial condition, are not charged. In order to be used to deliver electrochemical energy, such cells must be charged in order to transfer lithium to the anode from the lithium- containing cathode. During discharge-the lithium is transferred from the anode back to the catho4e. During a. subsequent recharge, the lithium is transferred back to the anode where it re-inserts. Upon subsequent charge and discharge, the lithium ions (Li'^) are transported between the electrodes. Such rechargeable batteries, having no free metallic species are called rechargeable ion batteries or rocking- chair batteries. See U.S. Patent Nos. 5,418,090/ 4,464,447; 4,194,062; and 5,130,2ir.
Preferred positive electrode active materials include LiCoOj, LiMnzO,, and LiNiOj. The cobalt compounds are relatively expensive and the nickel compounds are difficult to synthesize. A relatively economical positive electrode is LiMnzO,, for which methods of synthesis are known. The lithium cobalt oxide (LiCoOz) , the lithium manganese oxide (LiMn204), and the lithium nickel oxide (LiNiOj) all have a common disadvantage in that the charge capacity of a cell comprising such cathodes suffers a significant loss in capacity. That

is, the initial capacity available (amp hours/gram) from LiUniOi, LiNiOz, and LiCoOz is less than the theoretical capacity because significantly less than 1 atomic unit of lithi;im engages in the electrochemical reaction. Such an initial capacity value is significantly diminished during the first cycle operation and such capacity further diminishes on every successive cycle of operation. For LiNi02 and LiCoOj only about 0.5 atomic units of lithium is reversibly cycled during cell operation. Many attempts have been made to reduce capacity fading, for example, as described in U.S. Patent No. 4,828,834 by Nagaura et al. However, the presently known and commonly used, alkali transition metal oxide compounds suffer from relatively low capacity. Therefore, there remains the difficulty of obtaining a lithium-containing electrode material having acceptable capacity without disadvantage of significant capacity loss when used in a cell.

Stmmary of the Invention
The invention provides novel lithium-mixed metal materials which, upon electrochemical interaction, release lithium ions, and are capable of reversibly cycling lithium ions. The invention provides a rechargeable lithium battery which comprises an electrode formed from the novel lithium-mixed metal materials. Methods for making the novel lithium-mixed metal materials and methods for using such lithium-mixed metal materials in electrochemical cells are also provided. The lithium-mixed metal materials comprise lithium and at least one other metal besides lithium. Preferred materials are lithixim-mixed metal phosphates which contain lithium and two other metals besides lithium. Accordingly, • the invention provides a rechargeable lithium battery which comprises an electrolyte; a first electrode having a compatible active material; and a second electrode comprising the novel materials. In one aspect, the novel materials are lithium-mixed metal phosphates' which preferably used as a positive electrode active material, reversibly cycle lithium ions with the compatible negative electrode active material. Desirably, the lithium-mixed metal phosphate is represented by the nominal general formula LiaMIbMIIclPO^)^. Such compounds include LiiMIaMIIbPO, and LiaMI.MIIblPOJj; therefore, in an initial condition Osa^lorO^sa^S, respectively. During cycling, x quantity of lithium is released where 0 5 X s a. In the general formula, the sum of b plus c is up to about 2. Specific examples are LiiMIi.yMIIyPO, and Li3Ml2.yMIIy (PO4) 3.
In one aspect, MI and Mil are the same. In a preferred aspect, MI and Mil are different from one

another. At least one of MI and Mil is an element capable of an oxidation state higher than that initially present in the lithium-mixed metal phosphate compound. Correspondingly, at least one of MI and Mil has more than one oxidation state in the phosphate compound, and more than one oxidation state above the ground state M°. The term oxidation state and valence state are used in the art interchangeably.
In another aspect, both MI and Mil may have more than one oxidation state and both may be oxidizable from the state initially present in the phosphate compound. Desirably, Mil is a metal or semi-metal having a +2 oxidation state, and is selected from Groups 2, 12 and 14 of the Periodic Table. Desirably, Mil is selected from non-transition metals and semi-metals. In one embodiment. Mil has only one oxidation state and is nonoxidizable from its oxidation state in the lithium-mixed metal compound. In another embodiment. Mil has more than one oxidation state. Examples of semi-metals having more than one oxidation state are selenium and tellurium; other non-transition metals with more than one oxidation state are tin and lead. Preferably, Mil is selected from Mg (magnesium) , Ca (calcium), 2n (zinc), Sr (strontium), Pb (lead), Cd (cadmium), Sn (tin), Ba (barium), and Be (beryllium), and mixtures thereof. ' In another preferred aspect. Mil is a metal having a +2 oxidation state and having more than one oxidation state, and is oxidizable from its oxidation state in lithium-mixed metal compound.
Desirably, Ml is selected from Fe (iron), Co (cobalt), Ni (nickel), Mn (manganese), Cu (copper), V (vanadium), Sn (tin), Ti (titanium), Cr (chromium), and

mixtures thereof. As can be seen, MI is preferably selected from the first row of transition metals and further includes tin, and MI preferably initially has a +2 oxidation state.
In a preferred aspect, the product LiMIi_yMIIyP04 is an olivine structure and the product Li3MIi.y(P04) 3 is a rhombohedral or monoclinic Nasicon structure. In another aspect, the term "nominal formula" refers to the fact that the relative proportion of atomic species may vary slightly on the order of 2 percent to 5 percent, or more typically, 1 percent to 3 percent. In still another aspect, any portion of P (phosphorous) may be substituted by Si (silicon), S (sulfur), and/or As (arsenic); and any portion of 0 (oxygen) may be substituted by halogen, preferably F (fluorine). These aspects are also disclosed in U.S. Patent Application Serial Numbers 09/105,748 filed June 26, 1998, and 09/274,371 filed March 23, 1999; and in U.S. Patent No, 5,871,866 issued February 16, 1999, which is incorporated by reference in its entirety; each of the listed applications and patents are co-owned by the assignee of the present invention.
The metal phosphates are alternatively represented by the nominal general formulas such as Lii.^MIi.yMIIyP04 (0 ^ X s 1), and Li3.^Ml2.yMIIy (PO4) 3 signifying capability to release and reinsert lithium. The term "general" refers to a family of compounds, with M, X and y representing variations therein. The expressions 2-y and 1-y each signify that the relative amount of MI and Mil may vary. In addition, as stated above, MI may be a mixture of metals meeting the earlier stated criteria for MI. In addition. Mil may be a' mixture of metallic elements meeting the stated criteria

for Mil. Preferably, where Mil is a mixture, it is a mixture of 2 metallic elements; and where MI is a mixture, it is a mixture of 2 metals. Preferably, each such metal and metallic element has a +2 oxidation state in the initial phosphate compound.
The active material of the counter electrode is any material compatible with the lithium-mixed metal phosphate of the invention. Where the lithium-mixed metal phosphate is used as a positive electrode active material, metallic lithium, lithium-containing material,-or non-lithium-containing material may be used as the negative electrode active material. The negative electrode is desirably a nonmetallic insertion material. Desirably, the negative electrode comprises an active material from the group consisting of metal oxide, particularly transition metal oxide, metal chalcogenide, carbon, graphite, and mixtures thereof. It is preferred that the' anode active material comprises a carbonaceous material such as graphite. The lithium-mixed metal phosphate of the invention may also be used as a negative electrode material.
In another embodiment, the present invention provides a method of preparing a compound of the nominal general formula LijMIbMIIj,(POJd where 0
Preferably, the lithium-containing compound is in particle form, and an example is lithium salt. Preferably, the phosphate-containing anion compound is in particle form, and examples include metal phosphate salt and diammonium hydrogen phosphate (DAHP) and ammonium dihydrogen phosphate (ADHP) . The lithium compound, one or more metal compounds, and phosphate compound are included in a proportion which provides the stated nominal general formula. The starting materials are mixed together with carbon, which is included in an amount sufficient to reduce the metal ion of one or more of the metal-containing starting materials without full, reduction to an elemental metal state. Excess quantities of carbon and one or more other starting materials (i.e., 5 to 10% excess) may be used to enhance product quality. A small amount of carbon, remaining after the reaction, functions as a conductive constituent in the ultimate electrode formulation. This is an advantage since such . remaining carbon is very intimately mixed with the product active material. Accordingly, large quantities of excess carbon, on the order of 100% excess carbon are useable in the process. The carbon present during compound formation is thought to be intimately dispersed throughout the precursor and product. This provides many advantages, including the enhanced.conductivity of the product. The presence of carbon particles in the starting materials is also thought to provide nucleation sites for the production of the product crystals.
The starting materials are intimately mixed and theh reacted together where the reaction is initiated by heat and is preferably conducted in a nonoxidizing, inert atmosphere, whereby the lithium, metal from the metal compound(s), and phosphate combine to form the

LiaMIbMIIc(P04) Although it is.desired that the precursor compounds be present in a proportion which provides the stated general formula of the .product, the lithium compound may be present in an excess amount .on the order of 5 percent excess lithium compared to a stoichiometric mixture of the precursors. And the carbon may be present at up to 100% excess compared to the stoichiometric amount. The method of the invention may also be used to prepare other novel products, and to prepare known products. A number of lithium compounds are available as precursors, such as lithium acetate (LiOOCCHj), lithium hydroxide, lithium nitrate (LiNOj), lithium oxalate (LijCsO^), lithium oxide -(LijO), lithium phosphate (LijPOJ , lithium dihydrogen phosphate (LiH2P04), lithium

vanadate (LiVOj), and lithium carbonate (LizCOj),. The lithium carbonate is preferred for the solid state reaction since it has a very high melting point and commonly reacts with the other precursors before melting. Lithium carbonate h^s a melting point over 600'C and it decomposes in the presence of the other precursors and/or effectively reacts with the other precursors before melting. In contrast, lithium hydroxide melts at about 400°C. At some reaction temperatures preferred herein of over 450'C the lithium hydroxide will melt before any significant reaction with the other precursors occurs to an effective extent. This melting renders the reaction very difficult to control. In addition, anhydrous LiOH is highly hygroscopic and a significant quantity of water is released during the reaction. Such water needs to be removed from the oven and the resultant product may need to be dried. In one preferred aspect, the solid state reaction made possible by the present invention is much preferred since it is conducted at temperatures at which the lithium-containing compound reacts with the other reactants before melting. Therefore, lithium hydroxide is useable as a precursor in the method of the invention in combination with some precursors, .particularly the phosphates. The method of the invention is able to be conducted as an economical carbothermal-based process with a wide variety of precursors and over a relatively broad temperature range.
The aforesaid precursor compounds (starting materials) are generally crystals, granules, and powders and are generally referred to as being in particle form. Although- many types of phosphate salts are known, it is preferred to use diammonium hydrogen phosphate (NH4)2HP04 (DAHP) or ammonium dihydrogen phosphate (NHJH,P04 (ADHP) .

Both ADHP and DAMP meet the preferred criteria that the precursors decompose in the presence of one another or react with one another before melting of such precursor. Exemplary metal compounds are FezOa, FejOi,- V2O5, VO2, LiVOj-, NH4VO3, Mg(0H)2, Cao, MgO, Ca(0H)2, MnOz, MnzOj, Mn3(P04)2, CuO, SnO, Sn02, TiOz, Ti203, CrzOj, Pb02, PbO, Ba(0H)2/ BaO, Cd(0H)2. In addition, some starting materials serve as both the source of metal ion and phosphate, such as FePO^, Fe3(ppj2/ Zn3(P04)2, and Mg3(P04)2- Still others contain both lithium ion and phosphate such as Li3P04 and LiH2P04. Other exemplary precursors are H3PO4 (phosphoric acid); and PjOj (P4O10) phosphoric oxide; and HPO3 meta phosphoric acid, which is a decomposition product of P2O5. If it is desired to replace any of the oxygen with a halogen, such as fluorine, the starting materials further include a fluorine compound such as LiF. If it is desired to replace any of the phosphorous with silicon, then the starting materials further include silicon oxide (Si02) . Similarly, ammonium sulfate in the starting materials is useable to replace phosphorus with sulfur.
The starting materials are available from a number of sources. The following are typical. Vanadiiam pentoxide of the formula V2O5 is obtainable from any number of suppliers including Kerr McGee, Johnson Matthey, or Alpha Products of Davers, Massachusetts. Vanadium pentoxide has a CAS number of 1314-62-1. Iron oxide Fe303 is a common and very inexpensive material available in powder form from the' same suppliers. The other precursor materials mentioned above are also available from well known suppliers, such as those listed above.

The method of the invention may also be used to react starting materials in the presence of carbon to form a variety of other novel products, such as gamma-LiV205 and also to produce known products. Here, the carbon functions to reduce metal ion of a starting metal compound to provide a product containing such reduced metal ion. The method is particularly useful to also add lithium to the resultant product, which thus contains the metallic element ions, namely, the lithium ion and the other metal ion, thereby forming a mixed metal product. An example is the reaction of vanadium pentoxide (V2O5) with lithium carbonate in the presence of carbon to form gamma-liiVzOs. Here the starting metal ion V^^V*^ is reduced to V*^V*^. in the final product. A single phase gamma-LiVjOs product is not known to .have been directly and independently formed before.
As described earlier, it is desirable to conduct the reaction at a temperature where the lithium compound reacts before melting. The temperature should be about 400'C or greater, and desirably 450°C or greater, and preferably 500°C or greater, and generally will proceed at a faster rate at higher temperatures. The various reactions involve production of CO or CO2 as an effluent gas. The equilibrium at higher temperature favors CO formation. Some of the reactions are more desirably conducted at temperatures greater than 600"C; most desirably greater than 650°C; preferably 700°C or greater; more preferably 750°C or greater. Suitable ranges for many reactions are about 700 to S-SO^.C, or about 700 to SOO^C.
Generally, the higher temperature reactions produce CO effluent and the stoichiometry requires more

carbon be used than the case where CO2 effluent is produced at lower temperature. This is because the reducing effect of the C to CO^ reaction is greater than the C. to CO reaction. The C to COj reaction involves an increase in carbon oxidation state of +4 (from 0 to 4) and the C to CO reaction involves an increase in carbon oxidation state of +2 (from ground state zero to 2) . Here, higher temperature generally refers to a range of about 650°C to about 1000°C and lower temperature refers to up to about 650'C. Temperatures higher than 1200°C are not thought to be needed.
In one aspect, the method of the invention utilizes the reducing capabilities of carbon in a unique and controlled manner to produce desired products having structure and lithium content suitable for electrode active materials. The method of the invention makes it possible to produce products containing lithium, metal and oxygen in an economical and convenient process. The ability to lithiate precursors, and change the oxidation state of a metal without causing abstraction of oxygen from a precursor is heretofore unexpected. These advantages are at least in part achieved by the reductant, carbon, having an oxide whose free energy of formation becomes more negative as temperature increases. Such oxide of carbon is more stable at high temperature than at low temperature. This feature is used to produce products having one or more metal ions in a reduced oxidation state relative to the precursor metal ion .oxidation state. The method utilizes an effective-combination of quantity of carbon, time and temperature to produce new products and to produce known products in a hew way.

Referring back to the discussion of temperature, at about 700°C both the carbon to carbon monoxide and the carbon to carbon dioxide reactions are occurring. At closer to 600°C the C to CO2 reaction is the dominant reaction. At closer to 800,°C the C to CO reaction is dominant. Since the reducing effect of the C to CO2 reaction is greater, the result is that less carbon is needed per atomic unit of metal to be reduced. In the case of carbon to carbon monoxide, each atomic unit of carbon is oxidized from ground state zero to plus 2. Thus, fpr each atomic unit of metal ion (M) which is being reduced by one oxidation state, one half atomic unit of carbon is required. In the case of the carbon to carbon dioxide reaction, one quarter atomic unit of carbon is stoichiometrically required for each atomic unit of metal ion (M) which is reduced by one oxidation state, because carbon goes from ground state zero to a plus 4 oxidation state. These same relationships apply for each such metal ion being reduced and for each unit reduction in oxidation state desired.
It is preferred to heat the starting materials at a ran^ rate of a fraction of a degree to 10°C per minute and preferably about 2°C per minute. Once the desired reaction temperature is attained, the reactants (starting materials) are held at the reaction temperature for several hours. The heating is preferably conducted under non-oxidizing or inert gas such as argon or vacuum. Advantageously, a reducing atmosphere is not required, although it may be used if desired. After reaction, the products are preferably cooled from.the elevated temperature to ambient (room) temperature (i.e., 10°C to 40°C). Desirably, the cooling occurs at a rate similar to the earlier ramp rate, and preferably 2°C/minute

;ooling. Such cooling rate has been found to be adequate ;o achieve the desired structure of the final product. [t is also possible to quench the products at a cooling :ate on the order of about 100°C/minute. In some .nstances, such rapid cooling (quench) may be preferred.
The present invention resolves the capacity )roblem posed by widely used cathode active material. It las been found that the capacity and capacity retention )f cells having the preferred active material of the .nvention are improved over conventional materials. tptimized cells containing lithium-mixed metal phosphates, if the invention potentially have performance improved iver commonly used lithium metal oxide compounds..-idvantageously, the new method of making the novel .ithium-mixed metal phosphate compounds of the invention s relatively economical and readily adaptable to lommercial production.
Objects, features, and advantages of the
nvention include an electrochemical cell or battery
lased on lithium-mixed metal phosphates. Another object
s to provide an electrode active material which combines
he advantages of good discharge capacity and capacity
etention. It is also an object of the present invention
o provide electrodes which can be manufactured
conomically. Another object is to provide a method for
orming electrode active-material which lends itself to
lommercial scale production for preparation of large
■uantities. .

These and other objects, features, and advantages will become apparent from the following description of the preferred embodiments, claims,' and accompanying drawings.

Brief Description of the Drawings
Figure 1 shows ths results of.an x-ray diffraction analysis, of the LiFeP04 prepared according to the invention using CuKof radiation, A = 1.5405A. Bars refer to simulated pattern from refined cell parameters. Space Group, SG = Pnma {62). The values are a = 10.2883A (0.0020), b = 5.9759A (0.0037), c = 4.6717A (0.0012) 0.0072, cell volume = 287.2264A^ (0.0685). Density, p = 3.605 g/cc, zero =0.452 (0.003). Peak at full width half maximum, PFWHM = 0.21. Crystallite size from XRD data = 704A.
Figure 2 is a voltage/capacity plot of LiFePOi-containing cathode cycled with a lithium metal anode using constant current cycling at + 0.2 milliamps per square centimeter in a range of 2.5 to 4.0 volts at a temperature of about 23°C. The cathode contained 19.0mg of the LiFeP04 active material, prepared by the method of the invention. The electrolyte comprised ethylene carbonate (EC) and dimethyl carbonate (DMC) in a weight ratio of 2:1 and included a 1 molar concentration of LiPFj salt. The lithium-metal-phosphate containing electrode and the lithiiom metal counter electrode are maintained spaced apart by a glass fiber separator which is interpenetrated by the solvent and the salt.
Figure 3 shows multiple constant current cycling of LiFePO^ active material cycled with a lithium raetai anode using the electrolyte as described in connection with Figur4 2 and cycled, charge and discharge at ± 0.2 milliamps per square centimeter, 2.5 to 4.0 volts at two different temperature conditions, 23'C and 60°C. Figure 3 shows the excellent rechargeability of

the lithium iron phosphate/lithium metal cell, and also shows the excellent cycling and specific capacity (mAh/g) of the active material.
Figure 4 shows the results of an x-ray diffraction analysis, of the LiFeo.9Mgo.1PO4 prepared according to the invention, using CuKa radiation, X = I.5405A. Bars refer to simulated pattern from refined cell parameters SG = Pnma (62). The values are a = 10.'2688A (0.0069), b = 5.9709A (0.0072), c = 4.6762A (0.0054), cell volume = 286.7208A (0.04294), p = 3.617 g/cc, zero = 0.702 (0.003), PFWHM =.0.01, and crystallite = 950A.
Figure 5 is a voltage/capacity plot of LiFeo.9Mgo.iP04-containing cathode cycled with a lithium metal anode using constant current cycling at + 0.2 milliamps per square centimeter in a range of 2.5 to 4.0 volts. Other conditions are as described earlier with respect to Figure 2. The cathode contained 18.9mg of the LiFeo.9Mgo.1PO4 active material prepared by the method of the invention.
Figure 6 shows multiple constant current cycling of LiFeo.9Mgo.1PO4 cycled with a lithium metal anode using the electrolyte as described in connection with Figure 2 and cycled, charge and discharge at ± 0.2 milliamps per squ.are centimeter, 2.5 to 4.0 volts at two different temperature, conditions, 23°C and 60.°C. Figure 6 shows the excellent rechargeability of the lithium-metal-phosphate/lithium metal cell, and also shows the excellent cycling and capacity of the cell.

Figure 7 is a voltage/capacity plot of LiFeo.8Mgo.2P04-containing cathode cycled with a lithium metal anode using constant current cycling at ± 0.2 milliamps per square centimeter" in a range of 2.5 to 4.0 volts at 23°C. Other conditions are as described earlier with respect to Figure 2. The cathode contained 16mg of' the LiFeo..aMgo.2P04 active material prepared by the method of the invention.
Figure 8 shows the results of an x-ray diffraction analysis, of the LiFeo.9Cao.1PO4 prepared according to the invention, using CuKa radiation, X = I.5405A. Bars refer to simulated pattern from refined cell parameters SG = Pnma (62). The values are a = ' IO.3240A (0.0045), b = 6.0042A (0.0031), c = 4.6887A (0.0020), cell volume = 29.0.6370A (0.1807), zero = 0.702" (0.003), p = 3.62 g/cc, PFWHM = 0.18, and crystallite = 68OA.
Figure 9 is a voltage/capacity plot of LiFeo.BCao.2P Figure 10 is a voltage/capacity plot of" LiFeo.8Zno.2P04-containing 'cathode cycled with a lithium metal anode using constant current cycling at ± 0.2 milliamps per square centimeter in a- range of 2.5 to 4.0' volts at 23'C. ■ Other conditions are as described earlier with respect to Figure 2. The cathode contained 18.9mg

of the LiFeo.8Zn(j_2P04 active material, prepared by the method of the invention.
Figure 11 shows the results of an x-ray diffraction analysis of the gamma-Li,V205{x = 1, gamma LiVjOj) prepared according to the invention using CuKa radiation X = 1.5405A. The values are a = 9.687A (1), b == 3.603A (2), and c = 10.677A (3); phase type is gamma-LijVjOs (x = 1) ; symmetry is orthorhombic; and space group is Pnma.
Figure 12 is a voltage/capacity plot of gamma-LiVjOs-containing cathode cycled with a lithium metal anode using constant current cycling at + 0.2 milliajnps per square centimeter in a range of 2.5 to 3,8 volts at 23'C. Other conditions are as described earlier with respect to Figure 2. The cathode contained 21mg of the gamma-LiVjOs active material prepared by the method of the invention.
Figure 13 is a two-part graph based on multiple constant current cycling of gamma-LiVzOj cycled with a lithium metal anode using.the electrolyte as described in connection with Figure. 2 and cycled, charge and discharge at + 0.2 milliamps per square centimeter, 2.5 to 3.8 volts. In the two-part graph. Figure 13 shows the excellent rechargeability of the lithium-metal-oxide/lithium metal cell. Figure 13 shows the excellent cycling and capacity of the cell.
Figure 14 shows the results of an x-ray diffraction analysis of the Li3V2(P04)3 prepared according to the invention. The analysis is based on CuKa

radiation, K = 1.5405A. The values are a = 12.184A (2), b = 8.679A (2), c = 8.627A (3), and p = 90.457° (4).
Figure 15 shows the results of an x-ray-diffraction analysis of Li3V2{POj3 prepared according to a method described .in U.S. Patent No. 5,871,866. The analysis is based on CuKa radiation, X = 1.5405A. The values are a = 12.155A (2), b = 8.71lA (2), c = 8.645A (3); the angle beta is 90.175 (6); symmetry is Monoclinic; and space group is P2i/n.
Figure 16 is an EVS (Electrochemical Voltage Spectroscopy) voltage/capacity profile for a cell with cathode material formed by the carbothermal reduction method of the invention. The cathode material is 13.8mg of LijVztPO^ls. The cell includes a lithium metal counter electrode in an electrolyte comprising ethylene carbonate (EC) and dimethyl carbonate (DMC) in a weight ratio of 2:1 and including a 1 molar concentration of LiPFj salt. The lithium-metal-phosphate containing electrode arid the lithium metal counter electrode are maintained spaced apart by a fiberglass separator which is interpenetrated by the'solvent and the salt. The conditions are.± 10 mV steps', between about 3.0 and 4.2 volts, and the critical limiting current density is less than or equal to 0.1 mA/cm^.
Figure 17 is an EVS differential capacity versus voltage plot for the cell as described in connection with Figure 16.
Figure 18 shows multiple constant current cycling of LiFeo.8Mgo.2PO4 cycled with a lithium metal anode using the electrolyte as described in connection

with Figure 2 and cycled, charge and discharge at ± 0.2 milliamps per square centimeter, 2.5 to 4.0 volts at two different temperature conditions, 23°C and 60°C. Figure 18 shows the excellent rechargeability of the lithium-metal-phosphate/lithiura metal cell, and also shows the excellent cycling and capacity of the cell.
Figure 19 is a graph of potential over time for the first four complete cycles of the LiMg6.i.Feo.9P04/MCMB graphite cell of the invention.
Figure 20 is a two-part graph based on multiple constant current cycling of LiFeo.9Mgo.1PO4 cycled with an MCMB graphite anode using the electrolyte as described in connection with Figure 2 and cycled, charge and discharge at ± 0.2 milliamps per square centimeter, 2.5 to 3.6 volts, 23'C and based on a C/10 (10 hour) rate. In the two-part graph. Figure 20 shows the excellent rechargeability of the lithium-raetal-phosphate/gr-aphite cell. Figure 20 shows the excellent cycling and capacity of the cell.
Figure 21 is a graph of potential over time for the first three complete cycles of the gamma-LiVjOs/MCMB graphite cell of the invention.
Figure 22 is a diagrammatic representation of a typical laminated lithium-ion battery cell structure.
Figure 23 is a diagrammatic representation of a typical multi-cell battery cell structure.

Detailed Description of the Prefpi-r-rcrf BmV.Qdiman't-q
The present invention provides lithium-mixed metal-phosphates, which are usable as electrode active materials, for lithium: (Li* ) ion removal and insertion. Upon extraction of the lithium ions from the lithium-mixed-metal-phosphates, significant capacity is achieved,. In one aspect of the invention, electrochemical energy is provided when combined with a suitable counter electrode by extraction of a quantity x of lithium from lithium-raixed-metal-phosphates Li^.^MIbMIIclPOJ^. When a quantity x of lithium is removed per formula unit of the lithium-mixed-metal phosphate, metal MI is oxidized. In another aspect, metal MIX is also oxidized. Therefore, at least one of MI and Mil is oxidizable from its initial condition in the phosphate compound as Li is removed. Consider the following which illustrate the- mixed metal compounds of the invention: LiFei.ySnyPO^, has two oxidizable elements, Fe and Sn; in contrast, LiFei.yMgyPO^ has one oxidizable metal, the metal Fe.'
In another aspect, the invention provides a lithium ion battery which comprises an electrolyte; a negative electrode having an insertion active material; and a positive electrode comprising a lithium-mixed-metal-phosphate active material characterized by an ability to release lithium ions for insertion into the negative electrode active material. The lithium-mixed-metal-phosphate is desirably represented by the. nominal general formula LiaMIbMII(.(PO,) ^j. Although the metals Ml and Mil may be the same, it is preferred that the metals MI and Mil are different. Desirably, in the phosphate compound MI is a'metal selected from the group: Fe, Co, Ni, Mn, Cu, V, Sn, Ti, Cr and mixtures thereof, and MI is

most desirably a transition metal or mixture thereof selected from said group. Most preferably, MI has a +2 valence or oxidation state.
In another aspect. Mil is selected from Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, and mixtures thereof. Most preferably. Mil has a +2 valence or- oxidation state. The lithium-mixed-metal-phosphate is preferably a compound represented by the nominal general formula Lia.,MIbMIIc(P04)j,, signifying the preferred composition and its capability to release x lithium. Accordingly, during cycling, charge and discharge, the value of x varies as x greater than or equal to 0 and less than or equal to a. • The present invention resolves a capacity problem posed by conventional cathode active materials. Such problems with conventional active materials are described by Tarascon in U.S. Patent No. 5,425,932, using LiMnzO^ as an example. Similar problems are observed with LiCoOj, LiNiOj, and many, if not all, lithium metal chalcogenide materials. The present invention demonstrates that significant capacity of the cathode active material is utilizable and maintained.
A preferred novel procedure for forming the lithiiam-mixed-metal-phosphate. LiaMIbMIIc{P04)d compound active material will now be described. In addition, the preferred novel procedure is also applicable to formation of other lithium metal compounds, and will be described as such. The basic procedure will be described with reference to exemplary starting materials but is not• limited thereby. The basic process comprises conducting a reaction between a lithium compound, preferably lithium carbonate (LijCOj) , metal compound{s), for example, vanadium pentoxide (VjOj) , iron-oxide (Fe^Oj), and/or

manganese hydroxide, and a phosphoric acid derivative, preferably the phosphoric acid airanonium salt, diammonium hydrogen phosphate, (NHJjH (PO,) . Each of the precursor starting materials are available from a number of chemical outfits including Aldrich Chemical Company and Fluka. Dsing the method described herein, LiFeP04 and LiFeo.9Mgo.1PO4, Li3V2(PO,)3 were prepared with approximately a stoichiometric amount of LizCOa, the respective metal compound, and (NH4)2HP04. Carbon powder was included with these precursor materials. The precursor materials were initially intimately mixed and dry ground for about 30 minutes. The intimately mixed compounds were then pressed into pellets. Reaction was conducted by heating in an-oven at a preferred ramped heating rate to an elevated temperature, and held at such elevated
,temperature for several hours to complete formation of the reaction product. The entire reaction was conducted in a non-oxidizing atmosphere, under flowing pure argon gas- The flow rate will depend upon the size of the oven and the quantity needed to maintain the atmosphere. The oven was permitted to cool down at the end of the reaction period, where cooling occurred at a desired rate under .argon. Exemplary and preferred ramp rates, elevated reaction temperatures and reaction times are described herein. In one aspect, a ramp rate of Z^/minute to an elevated temperature in a range of 750°C to SOO'C was suitable along with a dwell (reaction time) of 8 hours. ■ Refer to Reactions. 1, 2, 3 and 4 herein. In another variation per Reaction 5, a reaction temperature of 600°C was used along with a dwell time of about one hour. In still another variation, as per Reaction 6, a
• two-stage heating was conducted, first to a temperature of 300°C and then to a temperature of 850°.

The general aspects of the above synthesis route are applicable to a variety of starting materials. Lithium-containing compounds include LizO (lithium oxide), LiHzPO, (lithium hydrogen phosphate), LijCjOi (lithium oxalate), LiOH (lithium hydroxide), LiOH.HzO (lithium hydroxide monohydride),'and LiHCOj (lithium hydrogen carbonate). The metal compounds(s) are reduced in the presence of the reducing agent, carbon. The same considerations apply to other lithium-metal- and phosphate-containing precursors. The thermodynamic considerations such as ease of reduction, of the selected precursors, the reaction kiaetics, and the melting point of the salts will cause adjustment in the general procedure, such as, amount of carbon reducing agent,' and the temperature of reaction.
Figures 1 through 21 which will be described more particularly below show characterization data and capacity in actual use for the cathode materials (positive electrodes) of the invention. Some tests were conducted in a cell comprising a lithium metal counter electrode . (negative electrode) and other tests were conducted in cells having a carbonaceous counter electrode. All of the cells had an ECrDMC-LiPFg electrolyte.
Typical cell configurations will now be described with reference to Figures 22 and 23; and such battery or cell utilizes the novel active material of the invention. Note that the preferred cell arrangement described here is illustrative and the invention is not limited thereby. Experiments are often performed, based on full and half cell arrangements, as per the following description. For test purposes, test cells are often

fabricated using lithium metal electrodes. When forming cells for use as batteries, it is preferred to use an insertion positive electrode as per the invention and a graphitic carbon negative electrode.
A typical laminated battery cell structure 10 is depicted in Figure 22. It comprises a negative electrode side 12, a positive electrode side 14, and an electrolyte/separator 16 there between. Negative electrode side.12 includes current collector 18, and positive electrode, side 14 includes current collector 22. A copper collector foil 18, preferably.in the form of an open mesh grid, upon which is laid a negative electrode membrane 20 comprising an insertion material such 'as carbon or graphite or low-voltage lithium insertion compound, dispersed in a polymeric binder matrix. An electrolyte/separator film 16 membrane is preferably a plasticized copolymer. This electrolyte/separator preferably comprises a polymeric separator and a suitable electrolyte for ion transport. The electrolyte/separator is positioned upon the electrode element and is-covered with a positive electrode membrane'24 comprising a composition of a finely divided lithium insertion compound in a polymeric binder matrix. An aluminum collector foil or grid 22 completes the assembly. Protective bagging material 40 covers the cell and prevents infiltration of air and moisture.
In another embodiment, a multi-cell battery configuration as per Figure 23 is prepared with copper current collector 51, negative electrode 53, electrolyte/separator 55, positive electrode 57, and aluminum current collector 59. Tabs 52 and 58 of the current collector elements form respective terminals for

the battery structure. As used herein, the terms "cell" and "battery" refer to an individual cell comprising anode/electrolyte/cathode and also refer to a multi-cell arrangement in a stack.
The relative weight proportions of the components of the positive electrode are generally: 50-90% by weight active material; 5-30% carbon black as the electric conductive diluent; and 3-20% binder chosen to . hold all particulate materials in contact with one another without degrading ionic conductivity. Stated ranges' are not. critical, and the amount of active material in an electrode may range from 25-95 weight percent. The negative electrode comprises about 50-95% by weight of a preferred graphite, with the balance constituted by the binder. A typical electrolyte separator film comprises approximately two parts polymer for every one part of a preferred fumed silica. The conductive solvent comprises any number of suitable solvents and salts. Desirable solvents and salts are described in U.S. Patent Nos. 5,643,695 and 5,418,091. One example is a mixture of EC:DMC:LiPFg in a weight ratio of about 60:30:10.
Solvents are selected to be used individually or in mixtures, and include dimethyl carbonate (DMC), diethylcarbonate (DEC), dipropylcarbonate (DPC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, lactones, esters,, glymes, sulfoxides, sulfolanes, etc. The preferred solvents are EC/DMC, EC/DEC, EC/DPC and EC/EMC. The salt content ranges from 5% to 65% by weight, preferably from 8% to 35% by weight.
l^

Those skilled in the art will understand that any number of methods are used to form films from the casting solution using conventional meter bar or doctor blade apparatus. It is usually sufficient to air-dry the films at moderate temperature to yield self-supporting films of copolymer composition. Lamination of assembled cell structures is accomplished by conventional means' by pressing between metal plates at a temperature of about 120-160°C. Subsequent, to lamination, the battery cell material may be stored either with the retained plasticizer or as a dry sheet after extraction of the plasticizer with a selective low-boiling point solvent. The plasticizer extraction solvent is not critical, and methanol or ether are often used.
Separator membrane element 16 is generally polymeric and prepared from a composition comprising a copolymer. A preferred composition is the 75 to 92% vinylidene fluoride with 8 to- 25% hexafluoropropylene copolymer (available commercially from Atochem North •America as Kynar FLEX) and ah organic solvent plasticizer. Such a copolymer composition is also preferred- for the preparation of the electrode membrane elements, since s'ubseguent laminate interface compatibility is ensured. The plasticizing -solvent may be one of the various organic-compounds commonly used as solvents for electrolyte salts, e.g., propylene carbonate or ethylene carbonate, as well as mixtures of these • compounds. Higher-boiling plasticizer compounds such as dibutyl phthalate, dimethyl phthalate, diethyl phthalate, and tris butoxyethyl phosphate are particularly suitable. Inorganic filler adjuncts, such as fumed alumina or silanized fumed silica, may be used to enhance the physical strength and melt viscosity of a separator

membrane and, 'in some compositions, to increase the subsequent level of electrolyte solution absorption.
In the construction of a lithium-ion battery, a current, collector layer of aluminum foil or grid is overlaid with a positive electrode film, or membrane, separately prepared as a coated layer of a dispersion of insertion electrode composition. This is typically an insertion compound such as LiMnjOj (LMO), LiCoOz, or LiNiOj, powder in a copolymer matrix solution, which is dried to form the positive electrode. An electrolyte/separator membrane is formed as a dried coating of a composition comprising a solution containing VdF:HFP copolymer and a plasticizer solvent is then / overlaid on the positive electrode film. A negative electrode membrane formed as a dried coating of a powdered carbon or other negative electrode material dispersion in a Vd.F:HFP copolymer matrix solution is similarly overlaid on the separator membrane layer. A copper, current collector foil' or grid is.laid upon the negative electrode layer to complete the cell assembly. Therefore, the VdF:HFP copolymer composition is used as a binder in all of the major cell components, positive electrode film, negative electrode film, and electrolyte/separator membrane. The assembled components are then heated under pressure to achieve heat-fusion bonding between the plasticized copolymer matrix electrode■and electrolyte components, and to the collector grids, to thereby form an effective laminate of cell elements. This produces an essentially unitary and flexible battery cell structure.
Examples of forming cells containing metallic lithium anode, insertion electrodes, solid electrolytes

and liquid electrolytes can be found in U.S. Patent Nos. 4,668,595; 4,830,939; 4,935,317; 4,990,413; 4,792,504; 5,037,712; 5,262,253; 5,300,373; 5,435,054; 5,463,179; 5,399,447; 5,482,795 and 5,411,820; each of which is. incorporated herein by reference in its entirety. Note that the older generation of cells contained organic polymeric and inorganic electrolyte matrix materials., with the polymeric being most preferred. The polyethylene oxide of 5,411,820 is an example. More modern examples are the VdF:HFP polymeric matrix. Examples of casting, lamination and formation of cells using VdF:HFP are as described in U.S. Patent Nos. 5,418,091; 5,460,904; 5,456,000; and 5,540,741;' assigned to Bell Communications Research, each of which is incorporated herein by reference in its entirety.
As described earlier, the electrochemical cell operated as per the invention, may be- prepared in a variety of ways. In one embodiment, the negative electrode may be metallic lithium. In more desirable embodiments, the negative electrode is an insertion active material, such as, metal oxides and graphite. . When a metal oxide active material is used, the components of the electrode are the metal oxide, electrically conductive carbon, and binder, in proportions similar to that described above for the positive electrode. In a preferred embodiment, the negative electrode active material is graphite particles. For test purposes, test cells are often fabricated using lithium metal electrodes. When forming cells for use as batteries, it is preferred to use an insertion metal oxide positive electrode and a graphitic carbon negative electrode. Various methods for fabricating electrochemical cells and batteries and for forming

electrode components are described herein. The invention is not, however, limited by any particular fabrication method.

Formation of Active Materials
EXAMPLE I
Reaction 1(a). LiFePO^ formed from FePO*
. FePO, 4 0.5 LijCOs + 0.5 C - LlFePO^ +0.5 CO2 + 0.5 CO
(a) Pre-mix reactants in the following,proportions
using ball mill. Thus,
1 mol FePO^ 150.82g 0.5 mol LijCOj 36.95g 0.5 mol carbon 6.Og
(but use 100% excess carbon - 12.0.0g)
(b) Pelletize powder mixture
(c) Heat pellet to 750'C at a rate of 2°/minute in flowing inert atmosphere (e.g. argon). Dwell for 8 hours at 750°C. under argon.
(d) Cool to room temperature at 2°/itiinute under argon.
(a) Powderize pellet.
Note that at 750°C this is predominantly a^CO reaction. This reaction is able to be conducted at a temperature in a range of about 700°C to about 950°C in argon as shown, and also under other inert atmospheres such as nitrogen or vacuum.

Reaction 1(b). LiFePO^ formed from FSzOj
0.5 FejOi +0.5 L±^CO^+ (NHJzHPO, + 0.5 C - LiFePO, + 0.5 CO2 + 2 NH3 + 3/2 H2O + 0.5 CO
(a) Premix powders in the following proportions
0.5 mol FejOj 79.e5g
• 0.5 mol LizCOa 36.95g
1 mol (NHJ2HPO4 132.06g
0.5'mol carbon 6.00g
(use 100% excess carbon -» 12.00g)
(b) Pelletize powder mixture
(c) Heat pellet to 750°C at a rate of 2'/minute in flowing inert atmosphere (e.g. argon). Dwell for 8 hours at 75.0°C' under argon.
(d) Cool to room temperature at 2°/minute under argon.
(e)■ Powderize EX2^MPIiE III
Reaction 1(c) . LiFePO, - from Fe3(P04)2 Two steps:

Part I. Carbothermal preparation of Fe3(P04)2
3/2 FSjOj + 2{NHJ2HP04 + 3/2 C - Fe3(P04)2 + 3/2 CO + 4NH3 + 5/2 HjO
(a) Preinix reactants in the following proportions
3/2 mol FejOj 239. 54g
2 mol (NHJ2HPO4 264.12g
3/2 mol carbon IS.OOg
(use 100% excess carbon - 36.00g)
(b) Pelletize powder mixture
(c) Heat pellet to 800°C at a rate of 2°/minute in flowing inert atmosphere (e.g. argon). Dwell for 8 hours at 750°C under argon.
(d) Cool to room temperature at 2°C/minute under argon.
(e) Powderize pellet.
Part II. Preparation of LiFePO^ from the FejlPO^jjOf Part I.
LisPO^ + Fe3(POj2-3 LiFePO^
(a) Premix reactants in the following proportions
1 mol Li3P04 115.79g
1 mol Fe3(P04)2 357.48g
(b) Pelletize powder mixture

(c) Heat pellet to VSO'C at a rate of 2°/minute in flowing inert atmosphere (e.g. argon). Dwell for 8 hours at 150°C under argon.
(d) Cool to. room, temperature at 2'C/minute under argon.
•(e) Powderize pellet.
EXAMPLE IV
Reaction 2(a). LiFeo.9Mgo.1PO4 (LiFei.yMgyP04) formed from FeP04
0.5 Li^COa + 0.9 FePO, + 0.1 Mg(0H)2 + 0.1 {NH4) 2HPO4 + 0.45C - LiFeo.9Mgo.1PO4 + O.5CO2 + 0.45CO + O.2NH3 + 0.25 H2O
(a) Pre-mix reactants in the following proportions
0.50 mol LijCOj = 36.95g
.0.90 mol FePO, = 135.74g
0.10 mol Mg(0H)2 = 5.83g "
0.10 mol (NH4)2HP04 = 1.32g
■ 0.45 mol carbon = 5.40g
(use 100% excess carbon - lO.BOg)
(b) Pelletize powder mixture
(c) Heat to TSO'C at a rate of 2'/minute in argon. Hold for 8 hours dwell at 750°C in argon
(d) Cool at a rate of 2°/minute

(e) Powderize pellet.
EZaMPLZ V
Reaction 2 (b) . LiFeo.9Mg(,.iP04 (LiFei_yMgyP04) foinmed from FezOj
0.50 LijCOj + 0,45 FSzOa + 0.10 Mg (OH) 2 + (NHJ2HPO4 + 0.45C -* LiFeo.9Mgo.1PO4 +0.5 COj + 0.45 CO + 2 NH3 + 1.6 H2O
(a) Pre-mix reactants in. following ratio

(use 100% fexcess carbon -lO.SOg)
(b) Pelletize powder mixture
(c) Heat to 750°C at a rate of 2'/niinut6 in argon. Hold for 8 hours dwell at 750°C in argon
(d) Cool at a rate of 2"/minute
(e) Powderize pellet.

Reaction 2 (c) , LiFeo.gMgo.iPO^ (LiFej.yMgyPOi) formed from LiHjPO,

(use 100% excess carbon - 10.80g)
(b) Palletize powder mixture
(c) Heat to 750'C at a rate of 2'/minute in argon.
Hold for 8 hours dwell at 750°C in argon
(d) Cool at a rate of 2°/ndnute
(e) Powderize pellet.
EXAMPLE VII
■ Reaction 3. Formation of LiFeo.9Cao.1PO4
(LiFei.yCayP04) f rom FejOj


(a) Pre-mix reactants in the following proportions

(100% excess carbon -> lO.SOg)
(b) Pelletize powder mixture
(c) Heat to 750°C at a rate of 2°/minute in argon.
Hold for 8 hours dwell at 750°C in argon
(d) Cool at a rate of 2°/minute
(e) Powderize pellet.
EXAMPLE VIII
Reaction 4. Formation of LiFeo.9Zno,iP04
(LiFei.yZnyPOt) f rom FejOj.

Pre-mix reactants in the following proportions


0.45 mol carbon = 5.40g (100% excess carbon - lO.SOg)
(b) Pelletize powder mixture
(c) Heat to 750°C at a rate of 2*'/minute in argon. Hold for 8 hours dwell at 750°C in argon
(d) Cool at a rate of 2°/minute
(e) Powderize pellet.
EZAMFLE IX
Reaction 5. Formation of gamma-LiVzOs (y)

(a) Pre-mix alpha V2O5, LijCOj and Shiwinigan Black (carbon) using ball mix with suitable media. Use a 25% weight excess of carbon over the reaction amounts above. For example, according to reaction above:

(bufuse 25% excess carbon - 3.75g)

(b) Pelletize powder mixture
(c) Heat pellet to 600°C in flowing argon (or other
inert atmosphere) at a heat rate of
approximately 2°/minute. Hold at 600°C for-
about 60 minutes,
(d) Allow to cool to room temperature in argon at
cooling rate of about 2°/minute.
(e) Powderize pellet using, mortar and pestle
This reaction is able to be conducted at a temperature in a range of about 400'C to about 650°C in argon as^shown, and also under other inert atmospheres such as nitrogen or vacuum. This reaction at this temperature rang? is primarily C -* COj. Note that the reaction C - CO primarily occurs at a temperature over about 650°C (HT, high temperature); and the reaction C -* CO2 primarily occurs at- a temperature of under about 650°C (LT, low temperature). The reference to about eSO'C is a;pproximate and the designation "primarily" refers to the predominant reaction thermodynamic'ally favored although the alternate reaction may occur to some extent.
KX2VMPLE X
Reaction 6. Formation of LijVz (P04)3


(a) Pre-mix reactants above using ball mill with
suitable media; Use a 25% weight excess of
carbon. Thus,
1 mol V2O5 181.88g
3/2 mol LizCOj 110.84g
3 mol {NHJ2HP04 396.ISg
1 mol carbon 12.01g
(but use 25% excess carbon - IS.Olg)
(b) Pelletize powder mixture
(c) Heat pellet at 2Vminute to 300'C to remove CO2 (from LijCOj) and to remove NH3, H2O. Heat in' an inert atmosphere (e.g. argon). Cool to room temperature.
(d) Powderize and repelletize
(e) Heat pellet in inert atmosphere at a rate of 2°C/minute to SSCC. Dwell' for 8 hours at 850°C
(f) Cool to room temperature at a rate of 2°/minute in argon.
(e) Powderize
This reaction is able to be conducted at a temperature in a range of' about '700°C to about 950°C in argon as shown, and also under other inert atmospheres such as nitrogen or vacuum. A reaction temperature greater than about 670°C ensures C -» CO reaction is primarily carried out.

Characterization of Active Materials and Formation and Testing of Cells
Referring to Figure 1, the final product LiFeP04, prepared from FezOj metal compound per Reaction . 1(b), appeared brown/black in color. This olivine material product included carbon that remained after reaction. Its CuKa x-ray diffraction pattern contained all of the peaks expected for this material as shown in Figure 1. The pattern evident in Figure 1 is consistent with the single phase olivine phosphate, LiFePO^. This is evidenced by the position of the peaks in terms of the scattering angle 2 6 (theta), x axis. The x-ray pattern showed no peaks due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed. Here the space group SG = pnma (62) and the lattice parameters from XRD refinement are consistent with the olivine structure. The values are a = 10.2883A (0.0020), b = 5.9759 (0.0037), c = 4.6717A (0.0012) 0.0072, cell volume = 287.2264A^ (0.0685). Density, p = 3.605 g/cc, zero = 0.452 (0.003). Peak at full width half maximum, PFWHM = 0.21. Crystallite size from XRD data = 704A.
The x-ray pattern demonstrates that the product of the invention was indeed the nominal formula LiFePO^. The term "nominal formula" refers to the fact that the relative proportion of atomic species may vary slightly on the order of 2 percent to 5 percent, or more typically, 1 percent to 3 percent, and that some portion of P may be substituted by Si, S or As; and some portion of O may be substituted by halogen, preferably F.

The LiFeP04, prepared as described immediately above, was tested in an electrochemical cell. The positive electrode was prepared as described above, using I9.0mg of active material. The positive electrode contained, on a weight % basis, 85% active material, 10% carbon black, and 5% EPDM. The negative electrode was netallic lithium. The electrolyte was a 2:1 weight ratio nixture of ethylene carbonate and dimethyl carbonate within which was dissolved 1 molar LiPFj. The cells were cycled between about 2.5 and about 4.0 volts with performance as shown in Figures 2 and 3.
Figure 2 shows the results of the first constant current cycling at 0.2 milliamps per square' centimeter between about 2.5 and 4.0 volts based upon about 19 milligrams of the LiFeP04 active material in the cathode (positive electrode). In an as prepared, as assembled, initial condition, the positive electrode active material is LiFePO4. The lithium is extracted Erom the LiFePO4 during charging of the cell. When fully charged, about 0.72' unit of lithium had been removed per Eormula unit. Consequently, the positive electrode active material corresponds to Li]._jtFeP04 where x appears :o be equal to about 0.72, when the cathode material is at 4.0 volts versus Li/Li*. The extraction represents approximately 123 milliamp hours per gram corresponding :o about 2.3 milliamp hours based on 19 milligrams active naterial. Next, the cell is discharged whereupon a quantity of lithium is re-inserted into the LiFePOi. The ce-insertion corresponds to approximately 121 milliamp lours per gram proportional to the insertion of sssentially all of the lithium. The bottom of the curve corresponds to approximately 2.5 volts. The total

cumulative capacity demonstrated during the entire extraction-insertion cycle is 244mAh/g.
Figure 3 presents data obtained by multiple constant current cycling at 0.2 milliamp hours per square centimeter of the LiFePOi versus lithium metal counter electrode between 2.5 and 4.0 volts. Data is shown for two temperatures, 23°C and 60°C. Figure 3 shows the excellent rechargeability of the LiFeP04 cell, and also shows good cycling and capacity of the cell. The performance shown after about 190 to 200 cycles is good and shows that electrode formulation is very desirable.
Referring to Figure 4, there is shown data for the final product LiFeo.9Mgo.1PO4, prepared from the metal compounds FejOj and Mg (OH) 2 - MglOHlj, per Reaction 2(b) . Its CuKot x-ray diffractibp pattern contained all of the peaks expected for this material as shown in Figure' 4. The pattern evident in Figure 4 is consistent with the single phase olivine phosphate compound, LiFeo.9Mgo.1PO4. This is evidenced by the position of 'the peaks in terms of the scattering angle 2 9 (theta), x. axis. The x-ray pattern showed no peaks due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed. Here the space group SG = Pnma (62) and the lattice parameters from XRD refinement are consistent with the olivine structure. The values are a = 10.2688A (0.0069), b = .5.9709A (0.0072), c = 4.6762A (0.0054), cell volume = 286.7208A (0.04294), p = 3.617 g/cc, zero = 0.702 (0.003), PFWHM = 0.01, and crystallite = 950A.
The x-ray pattern demonstrates that the product of the invention was indeed the nominal formula

LiFeo.gMgo.iPO^. The term "nominal formula" refers to the fact that the relative proportion of atomic species may vary slightly on the order.of 2 percent to 5 percent, or more-typically, 1 percent to 3 percent, and that some substitution of P and 0 may be made while maintaining the basic olivine structure.
The LiFeo,jMg{,.iP04^ prepared as described immediately above, was tested in an electrochemical cell. The. positive electrode was prepared as described above, using 18.9mg of active materials. The positive electrode, negative electrode and electrolyte were prepared as described earlier and in connection with Figure 1. The cell was between about 2.5 and about 4.0 volts with performance, as shown in Figures 4, 5 and 6.
Figure 5 shows the results of the first constant current cycling at 0.2 milliamps per square centimeter between about 2.5 and 4.0 volts based upon about 18.9 milligrams of the LiFeo.9Mgo.1PO4 active material in the cathode (positive electrode). In an as-prepared, as assembled, initial condition, the positive electrode active material is LiFeo.5Mgo.1PO,. The lithium is extracted from the'LiFeo.gMgo.iPO^ during charging of the cell. When fully charged, about 0.87 units of lithium have been removed per formula unit. Consequently, the positive electrode active material corresponds to Li1.jtFeo.9Mgo.1PO4 where x appears to be equal to about 0.87, when th.e cathode material is at 4.0 volts versus Li/Li*. The extraction represents approximately 150 milliamp hours per .gram corresponding to about 2.8 milliamp hours based on 18.9 milligrams active material. Next, the cell is discharged whereupon a quantity of lithium is re-inserted into the LiFeo.9Mgo.1PO4'. The re-

insertion corresponds to approximately 146 milliamp hours per gram proportional to the insertion of essentially all of the lithiUm. The bottom of the curve corresponds to approximately 2.5. volts. The total cumulative specific capacity over the entire cycle is 296 mAhr/g. This material has a much better cycle profile than the LiFeP04. Figure 5 {LiFeo.9Mgo.1PO4) shows a very well defined and sharp peak at about 150 mAh/g. In contrast. Figure 2 (LiFeP04) shows a very shallow slope leading to the peak at about 123 mAh/g. The Fe-phosphate (Figure 2) provides 123 mAh/g compared to its theoretical capacity of 170 mAh/g. This ratio of 123/170,"72% is relatively poor compared to the Fe/Mg-phosphate. The Fe/Mg-phosphate (Figure 5) provides 150 mAh/g compared to a theoretical capacity of 160, a ratio of 150/160 or 94%.
Figure 6 presents data obtained by multiple constant current cycling at 0.2 milliamp hours per square centimeter of the LiFeo.9Mgo.1PO4 versus lithium metal counter electrode between 2.5 and 4.0 volts. Figure 6 shows the excellent rechargeability of the Li/LiFeo.9Mgo.iP04 cell, and also shows good cycling and capacity of the cell. The performance shown after about 150 to 160 cycles is very good and shows that electrode formulation LiFeo.9Mgo.1PO4 performed significantly better than the LiFePO,. Comparing Figure 3 (LiFePOi) to Figure 6 (LiFeo.9Mgo.1PO4) it can be seen that the Fe/Mg-phosphate maintains its capacity .over prolonged cycling, whereas the Fe-phosphate capacity fades significantly.
Figure 7 shows the results of the first constant current cycling at 0.2 milliamps per square centimeter between about 2.5 and 4.0 volts based upon about 16 milligrams of the LiFeo.8Mgo.2PO4 active material

in the cathode (positive electrode), In an as prepared, as. assembled, initial condition, the positive electrode active material is LiFeo.BMgo.zPO,. The lithixim is extracted from the LiFeo.gMgo.^PO^ during charging of the cell. When fully charged, about 0.79 units of lithium have been removed per formula unit. Consequently, the positive electrode active material corresponds to LiFeo;8Mgo.2P04 where x appears to be equal to about 0.79, when the cathode material is at 4.0 volts versus Li/Li*. The extraction approximately 140 milliamp hours per gram corresponding to about 2.2 milliamp hours based on 16 milligrams active material. Next, the cell is discharged whereupon a quantity of lithium is re-inserted into the LiFeo.BMgo.2PO4- The re-insertion corresponds to approximately 122 milliamp hours per gram proportional to the insertion of essentially all of the lithium. The bottom of the curve corresponds to approximately 2.5 volts. The total cumulative specific capacity over the entire cycle is 262 mAhr/g.
Referring to Figure 8, there is shown data for the final product LiFeo.9Cao.1PO4, prepared from FejOa and Ca(0H)2 by Reaction 3. Its CuKa x-ray diffraction pattern contained all of the peaks expected for this material as shown in Figure 8. The pattern evident in Figure 8 is consistent with the single phase olivine phosphate compound, LiFeo.9Cao.1PO4. This is evidenced by the position of the peaks in terms of the scattering angle 2 6 (theta), x axis. The x-ray pattern showed no peaks due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed. Here the space group SG = Pnma (62) and the lattice parameters from XRD refinement are consistent with olivine. The values are a = 10.3240A (0.0045), b =

6.0042A (0.0031), c = 4.6887A (0.0020), cell volume = 290.6370A (0.1807), zero = 0.702 (0.003), p = 3.62 g/cc, PFWHM = 0.18, and crystallite = 68oA. The x-ray pattern demonstrates that the product of the invention was indeed the nominal formula LiFeo.9Ca(,,iP04.
Figure 9 shows the results of the first constant current cycling at 0.2 ftiilliamps per square centimeter between about 2.5 and 4.0 volts based upon about 18.5- milligrams of the LiFeo.BCao.2PO4 active material in the cathode (positive electrode). In an as prepared, as assembled, initial condition, the positive electrode active material is LiFeo.8Cao.2PO4. The lithium is extracted from the LiFeo.BCao.2PO4 during charging'of the cell. When fully charged, about 0.71 units of lithium have been removed per formula unit. Consequently, the positive electrode active material corresponds to LiFeo.8Cao.2PO4 where x appears to be equal to about 0.71, when the cathode material is at 4.0 volts versus Li/Li*. The extraction represents approximately 123 milliamp hours per gram corresponding to about 2.3 milliamp hours based on 18.5 milligrams active material. Next, the cell is discharged whereupon a quantity, of lithium is re-inserted into the LiFeo.8Cao.2PO4. The re¬insertion corresponds to approximately 110 milliamp hours per, gram proportional to the insertion of nearly all of the lithium. The bottom of the curve corresponds to approximately 2.5 volts. The total specific cumulative capacity over the entire cycle is 233 mAhr/g.
Figure 10 shows the results of the first constant current cycling at 0.2 milliamps per square centimeter between about 2.5 and 4.0 volts based upon about 18.9 milligrams of the LiFeo.8Zno.2PO4 olivine active

material in the cathode (positive electrode). In an as prepared, as assembled, initial condition, the positive electrode active material is LiFeo.BZno.2PO4, prepared from FejOj and Zn3(P04)2 by Reaction 4. The lithium is extracted from the LiFeo.8Zno.2PO4 during charging of the cell. When fully charged, about 0.74 units of lithium have been removed per formula unit. Consequently, the positive electrode active material corresponds to Li^. jtFe0.8Zn0.2PO4 where x appears to be equal to about 0.74, when the cathode material is at 4.0 volts versus Li/Li*. The extraction represents approximately 124 milliamp hours per gram corresponding to about 2.3 milliamp hours based on 18.9 milligrams active material. Next, the cell is discharged whereupon a quantity of lithium is re¬inserted into the LiFeo.8Zno.2PO4. The re-insertion corresponds to approximately 108 milliamp hours per gram proportional to the insertion of nearly all of the lithium. The bottom of the curve corresponds to approximately 2.5 volts.
Referring to Figure 11, the- final product , LiVjOj, prepared by Reaction 5, appeared black in color. Its CuKa x-ray diffraction pattern contained all of the peaks expected for this material as shown in Figure 11. The pattern evident in Figure 11 is consistent with a single oxide compound gamma-LiVzOj. This is evidenced by the position of the peaks in terms of the scattering angle 2 9 (theta), x axis. The x-ray pattern showed no peaks due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed.
The x-ray pattern demonstrates that the product of-the invention was indeed the nominal formula gamma-

LiVjOs. The term "nominal formula" refers to the fact that the relative proportion of atomic species may vary slightly on the order of 2 percent to 5 percent, or more typically, 1 percent to 3 percent.
The LiVaOj prepared as described immediately above, was tested in an electrochemical cell. The cell was prepared as described above and cycled with performance as shown in Figures 12 and 13.
Figure 12 shows the.results of the first ■ constant current cycling at 0.2 milliamps per square centimeter between about 2.8 and 3.8 volts based upon about 15.0 milligrams of the LiVjOj active material in the cathode (positive electrode). In an as prepared, as asseinbled, initial condition, the positive electrode active material is LiVzOg. The lithium is extracted from the LiVjOs during charging of the cell. When fully charged, about 0.93 unit of lithi\im had been removed per formula unit. Consequently, the positive electrode active material corresponds to Li^.^VjOj where x appears to be equal to about 0.93, when the cathode material is at 3.8 volts versus Li/Li*. The extraction represents approximately 132 milliamp hours per gram corresponding to about 2.0 milliamp hours based on 15.0 milligrams active material. Next, the cell is discharged whereupon a quantity of lithium is re-inserted into the LiVzOj. The re-insertion corresponds to approximately 130 milliamp hours per gram proportional to the insertion of essentially all of the lithium. The bottom of the curve corresponds to approximately 2.8 volts.
Figure 13 presents data obtained by multiple constant current cycling at 0.4 milliamp hours per square

centimeter (C/2 rate)of the LiVzOj versus lithium metal counter electrode between 3.0 and 3.75 volts. Data for two temperature conditions are shown, 23°C and 60°C. Figure 13 is a two part graph with Figure 13A showing the excellent rechargeability of the LiV205. Figure 13B shows good cycling and capacity of the cell. The performance shown up to about 300 cycles is good.
Referring to Figure 14, the final product Li3V2(P04)3, prepared by Reaction 6, appeared green/black in color. Its CuKa x-ray diffraction pattern contained all of the peaks expected for this material.as shown in Figure 14. The pattern evident in Figure 14 is consistent with a single phosphate compound Li3V2(P04)3 of the monoclinic, Nasicon phase. This is evidenced by the position of the peaks in terms of the scattering angle 2 9 (theta), x axis. The x-ray pattern showed no peaks due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed.
The x-ray pattern demonstrates that the product of the invention was indeed the nominal formula Li3V2{P04)3 . The term "nominal formula" refers to the fact that the relative proportion, of atomic species may vary slightly oh the order of 2 percent to 5 percent, or more typically, 1 percent to 3 percent; and that substitution . of P and 0 may occur.
The Li3V2(P04) 3 prepared as described immediately above, was tested in an electrochemical cell. The cell was prepared as described above, using 13.8mg of active material. The cell was prepared -as described above and cycled between about 3.0 and about 4.2 volts using the EVS technique with performance as shown in Figures 16 and.

17. Figure 16 shows specific capacity versus electrode potential against Li. Figure 17 shows differential capacity versus electrode potential against Li.
A comparative method was used to form Li3V2{P04)3. Such method was reaction without carbon and under .Hj-reducing gas as described in U.S. Patent No. 5,871,866. The final product, prepared as per U.S. Patent No. 5,871,8 66, appeared green in color. Its CuKa x-ray diffraction pattern contained all of the peaks expected for this material as shown in Figure 15. The pattern evident in Figure 15 is consistent with a-monoclinic Nasicon single phase phosphate compound Li3V2(P04)3. This is evidenced by the position of the peaks in terms of the scattering angle 2 6 (theta), x axis. The x-ray pattern showed no peaks- due to the presence of precursor oxides indicating that the solid state reaction is essentially entirely completed. Chemical analysis for lithium and vanadium by atomic absorption spectroscopy showed, on a percent by weight basis, 5.17 percent lithium and 26 percent vanadium. This is close to the expected result of 5.11 percent lithium and 25 percent vanadium.
The chemical analysis and x-ray patterns of Figures 14 and. 15 demonstrate that the product of Figure 14 was the same as that of Figure 15. The product of Figure 14 was prepared without the undesirable Hj atmosphere and was prepared by the novel carbothermal solid state synthesis of the invention.
Figure 16 shows a voltage profile of the test cell, based on the Li3V2(P04)3 positive electrode active material made by the process of the invention and as

characterized in Figure 14. It was cycled against a lithium metal counter electrode. The data shown in Figure 16 is based on the Electrochemical Voltage Spectroscopy (EVS) technique. Electrochemical and kinetic data were recorded using the Electrochemical Voltage Spectroscopy (EVS) technique. Such technique is ■known in the art as described by J. Barker in Synth, Met 28, D217 (1989); Synth. Met. 32, 43 (1989); J. Power Sources, 52, 185 (1994); and Electrochemica Acta, Vol. 40, No. 11, at 1603 (1995). Figure 16 clearly shows and highlights the reversibility of the product. The positive electrode contained about 13.8 milligrams of the Li3V2(P04)3 active material. The positive electrode showed a performance of about 133 milliamp hours per gram on the first discharge. In Figure 16, the capacity in, and the capacity out are essentially the same, resulting in essentially no capacity loss; Figure 17 is an EVS differential capacity plot based on Figure 16. As can be seen from Figure 17, the relatively symmetrical nature of peaks indicates good electrical reversibility, there are small peak separations (charge/discharge), and good correspondence between peaks above and below the zero axis. There are essentially no peaks that can be related to irreversible reactions, since all peaks above the axis (cell charge) have'corresponding peaks below the axis (cell discharge),. and there is essentially no separation between the peaks above and below the axis. This shows that the carbothermal method of the invention produces high quality electrode material.
Figure 18 presents data obtained by multiple constant current cycling, at 0.2 milliamp hours per square centimeter of the LiFeo.8Mgo.2PO4 versus lithium metal counter electrode between 2.5 and 4.0 volts. Figure 18

shows the excellent rechargeability of the Li/LiFeo.aMgo.zPO^ cell, and also shows good cycling and capacity of the cell. The performance shown after about 110 to 120 cycles at 23*0 is very good and shows that electrode formulation LiFeo.BMgo.2PO4 performed significantly better than the LiFePO^. The cell cycling test at 60"C was started after the 23°C test and was ongoing. Comparing Figure 3 (LiFePOJ to Figure 18 {LiFeo.8Mgo.2PO4), it can be seen that the Fe/Mg-phosphate maintains its capacity over prolonged cycling, whereas the Fe-phosphate capacity fades significantly.
In addition to the above cell tests, the, active materials of the invention were also cycled against insertion anodes in non-metallic, lithium ion, rocking chair cells.
The lithium mixed metal phosphate and the lithium metal oxide were used to formulate a cathode electrode. The electrode was fabricated by solvent casting a slurry of the treated, enriched lithium manganese oxide, conductive carbon, binder, plasticizer and solvent. The conductive carbon used was Super P (MMM Carbon). Kynaf Flex 2801® was used as the binder and electronic grade acetone was used as a solvent. The preferred plasticizer was dibutyl phthalate (DPB). The slurry was cast .onto glass and a free-standing electrode was formed as the solvent was evaporated. In this example, the cathode had 23.1mg LiFeo.9Mgo.1PO4 active material. Thus, the proportions are as follows on a percent weight basis: 80% active material; 8% Super P carbon; and 12% Kynar binder.

A graphite counter electrode was prepared for se with the aforesaid cathode. The graphite counter lectrode served as the anode in the electrochemical ell. The anode had 10.8 mg of the M'CMB graphite active aterial. The graphite electrode was fabricated by olvent casting a slurry of MCMB2528 graphite, binder, nd casting solvent. MCMB2528 is a mesocarbon microbead aterial supplied by Alumina Trading, which is the U.S. istributor for the supplier, Osaka Gas Company of Japan, his material has a density of about 2.24 grams per cubic entimeter; a particle size maximum for at least 95% by eight of the particles of 37 microns; median size of bout 22.5 microns and an interlayer distance of about .336. As in the case of the cathode, the binder was a opolymer of polyvinylidene difluoride (PVdF) and exafluoropropylene (HFP) in a wt. ratio of PVdF to HFP f 88:12. This binder is sold under the designation of ynar Flex 2801®, showing it's a registered trademark, ynar Flex is available from Atochem Corporation. An lectronic grade solvent was used. The slurry was cast nto glass and a free standing electrode was formed as he casting solvent evaporated. The electrode omposition was approximately as follows on a dry weight asis: 85% graphite; 12%.binder; and 3% conductive arbon.
A rocking chair baittery was prepared comprising he anode, the cathode, and an electrolyte. The ratio of he active cathode mass to the active anode mass was bout 2.14:1. The two electrode layers were arranged ith an electrolyte layer in between, and the layers were aminated together using heat and pressure as per the ell Comm. Res. patents incorporated herein by reference arlier. In a preferred method, the cell is activated

with EC/DMC solvent in a weight ratio of 2:1 in'a solution containing 1 M LiPFg salt.
Figures 19 and 20 show data for the first four complete cycles of the, lithium ion cell having the LiFeo.9Mgo.1PO4 cathode and the MCMB25'28 anode. The cell comprised 23.1mg active LiFeo.9Mgo.1PO4 and 10.8mg active MCMB2528 for a cathode to anode mass ratio of 2.14. The cell was charged and discharged at 23'C at an approximate C/10 (10 hour) rate between voltage limits of 2.50 V and 3.60 V. The voltage profile plot (Figure 19) shows the variation in cell voltage versus time for the LiFeo.9Mgo.1PO4/MCMB2528 lithium ion cell. The symmetrical nature of the charge-discharge is clearly evident. • trhe small degree of voltage hysteresis between the charge and discharge processes is evidence for the low overvoltage in the system, which is very good. Figure 20 shows the variation of LiFeo.9Mgo.1PO4 specific capacity with cycle number.' Clearly, over the cycles shown, the material demonstrates good cycling stability.
Figure 21 shows data for the first three complete cycles of the lithium ion cell having the garama-LiV205 cathode and the MCMB2528 anode. The cell prepared was a rocking chair, lithium ion cell as described above. The cell comprised 29.Img gamma-LiV2O5 .cathode active material and 12.2mg MCMB2528 anode active material, for a cathode to anode mass ratio of 2.39. As stated earlier, the liquid electrolyte used was EC/DMC (2:1) and IM LiPFj. The cell was charged and discharged at 23°C at an approximate C/10 (10 hour) rate between voltage limits of 2.50 V and 3.65 V. The voltage profile plot (Figure 21) shows the variation in cell voltage versus time for the LiV2G5/MCMB2528 lithium ion cell. The symmetrical nature

of the charge-discharge is clearly evident. The small degree of voltage hysteresis between the charge and discharge processes is evidence for the low overvoltage in the system, which is very good.
In summary, the invention provides new compounds LiaMIbMIIeCPOili and gamma-LiVjOs by new'methods which are adaptable to commercial scale production. The LiiMIi.yMIIyPOi compounds are isostructural olivine compounds as demonstrated by XRD analysis. Substituted compounds, such as LiFei.yMgyP04 show better performance than LiFePO^ unsubstituted compounds when used as electrode active materials. The method of the invention utilizes the reducing capabilities of carbon along with selected precursors and reaction conditions to produce high quality products suitable as electrode active materials or as ion conductors. The reduction capability of carbon over a broad temperature range is selectively applied along with thermodynamic and kinetic considerations to provide an energy-efficient, economical and convenient process to produce compounds of a desired composition and structure. This is in contrast to known methods.
Principles of carbothermal reduction have been I' applied to produce pure metal from metal oxides by
removal of oxygen. See, for example, U.S. Patent Nos. 2,580,878, 2,570,232, 4,177,060, and 5,803,974. Principles of carbothermal and thermal reduction have also been used to form carbides. See, for example, U.S. ) Patent Nos. 3,865,745 and 5,384,291; and non-oxide
ceramics (see U.S. Patent No. 5,607,297). Such methods are not known to have been applied to form lithiated products or to form products without oxygen abstraction

from the precursor. The methods described with respect to the present invention provide high quality products which are prepared from precursors which are lithiated during the reaction without oxygen abstraction. This is a surprising result. The new methods of the invention also provide new compounds not known to have been made before.
For example, alpha-VjOj is conventionally lithiated electrochemically against metallic lithium. Thus, alpha-VjOs is not suitable as a source,of lithium for a cell. As a result, alpha-VzOj is not used in an ion cell. In the present invention, alpha-V2O3 is lithiated by carbothermal reduction using a simple lithium-containing compound and the reducing capability of carbon to form a gamma-LiV2O5. The single phase compound, gamma-LiVjOs is not known to have been directly and independently prepared before. There is not known to be a direct synthesis route. Attempts to form it as a single phase resulted in a mixed phase product containing one or more beta phases and having the formula LijjVjOs with 0
vanadium is reduced from V15 to V4. (See Reaction 5). The new product, gamma-LiV2O5 is air-stable and suitable is an electrode material for an ion cell or rocking chair 5attery.
The convenience and energy efficiency of the 3resent process can also be contrasted to known methods :or forming products under reducing atmosphere such as Hj Which is difficult to control, and from complex and Expensive precursors. In the present invention, carbon Ls the reducing agent, and simple, inexpensive and even laturally occurring precursors are useable. For example, -t is possible to produce LiFePO^ from FejOg, a simple ;ommon oxide. (See Reaction lb). The production of; jiFePO^ provides a good example of the thermodynamic and cinetic features of the method. Iron phosphate is reduced by carbon .and lithiated over a.broad temperature range. At about 600°C, the C to COj reaction jredominates and takes about a week to complete. At ibout 750'C, the C to CO reaction predominates and takes ibout 8 hours to complete. The C to CO2 reaction requires less carbon reductant but takes longer due to :he low temperature kinetics. The C to CO reaction requires about twice as much carbon, but due to the high :emperature reaction kinetics, it proceeds relatively East. In both cases, the Fe in the precursor FezOs has 3xldation state +3 and is reduced to oxidation (valence) state. +2 in the product LiFePO, .• The C to CO reaction requires that H atomic unit of carbon be used for each atomic unit of Fe reduced by one valence state. The CO :o CO2 reaction requires that 1/4 atomic unit of carbon 36 used for each atomic unit of Fe reduced by one valence state.

The active materials of the invention are also characterized by being stable in an as-prepared condition, in'the presence of air and particularly humid air. This is a striking advantage, because it facilitates preparation of and assembly of battery cathodes and cells, without the requirement for controlled atmosphere. This feature is particularly important, as those skilled in the art will recognize that air stability, that is, lack of degradation on exposure to air, is very important for commercial processing. Air-stability is known in the art to more specifically indicate that a material does not hydrolyze in presence of moist air. Generally, air-stable materials are also characterized by Li being extracted therefrom above about 3.0 volts versus lithium. The higher the extraction potential, the more tightly bound the lithium ions are to the host lattice. This tightly bound property generally confers air stability on the material. The air-stability of the materials of the ' invention is consistent with the stability demonstrated by cycling at the conditions stated herein. This"- is in contrast to materials which insert Li at lower voltages, below about 3.0 volts versus lithium, and which are not air-stable,' and which hydrolyze in moist air.
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 following claims.


WE CLAIM:
A method of preparing a single phase lithium mixed metal compound from starting materials comprising particles comprising a lithium compound selected from the group consisting of lithium acetate, lithium nitrate, lithium oxalate, lithium oxide, lithium phosphate, lithium dihydrogen phosphate, lithium hydrogen phosphate, lithium vanadate and lithium carbonate and a transition metal, wherein the starting material additionally comprises a reducing agent comprising carbon and at least one of the starting material comprises a compound containing a polyanion capable of forming a crystal lattice; combining the starting material particles to form a mixture; heating the mixture to reduce at least one metal of the starting material without full reduction to the elemental state to form the single phase lithium mixed metal compound.
The method as claimed in claim 1, wherein the starting material comprises a lithium compoimd selected from the group consisting of lithium acetate, lithium nitrate, lithium oxalate, lithium oxide, lithium phosphate, lithium dihydrogen phosphate, lithium hydrogen phosphate, lithium vanadate, and lithium carbonate, and the reaction product is a single phase reaction product.
The method as claimed in claims 1 or 2, wherein the starting material comprises lithium compound selected from the group consisting of lithium carbonate, lithium phosphate, lithium oxide, lithium vanadate, and mixtures thereof
The method as claimed in claims 1 or 2, wherein the starting material comprises a compound of a metal selected from the group consisting of Fe, Co, Ni, Mn, Cu, V, Sn, Ti, Cr, and mixtures thereof

The method as claimed in claims 1 or 2, wherein the starting material comprises a metal compound selected from the group consisting of Fe203, V2O5, FeP04, VO2, Fe304, LiVOs, NH4VO3, and mixtures thereof
The method as claimed in claims 1 or 2, wherein the starting material contains a second metal compound having a second metal ion that is not reduced and that forms a part of said reaction product.
The method as claimed in claims 1 or 2, wherein said second metal compound is a compound of a metal selected from the group consisting of Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, and mixtures thereof.
The method as claimed in claim 7, wherein the second metal compound is selected from the group consisting of magnesium hydroxide and calcium hydroxide.
The method as claimed in claims 1 or 2, wherein the starting material includes a phosphate compound and the reaction product is a lithium metal phosphate.
The method as claimed in claim 9, wherein said phosphate compound is selected from the group consisting of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, lithium dihydrogen phosphate, and mixtures thereof.
The method as claimed in claims 1 or 2, wherein the starting material is a metal oxide or a metal phosphate.

The method as claimed in either of claims 1 or 2, wherein the starting material comprises V2O5.
The method as claimed in either of claims 1 or 2, wherein the starting material has a compound containing a polyanion capable of forming a crystal lattice.
The method as claimed in claim 13, wherein the starting material comprises an iron compound; a hydroxide selected from the group consisting of magnesium hydroxide and calcium hydroxide; a lithium compound; and a phosphate compound.
The method as claimed in claim 13, wherein the starting material comprises lithium carbonate; iron phosphate; diammonium hydrogen phosphate; and a hydroxide selected from the group consisting of magnesium hydroxide and calcium hydroxide.
The method as claimed in any of claims 1, 2, and 13, wherein the starting material comprises at two metal compounds, a first being an oxide of a transition metal selected from Groups 4 to 11 inclusive of the Periodic Table having a +2 valence state, and a second being a compound of a metal selected from Groups 2, 12, and 14 of the Periodic Table having a +2 valence state.
The method as claimed in any of claims 1, 2, or 13, wherein the starting material comprises a lithium compound, and a phosphate of a metal selected from the group consisting of Mg, Ca, Zn, Sr, Pb, Cd, Sn, Ba, Be, and mixtures thereof

The method as claimed in any of claims 1 to 17, wherein the heating is conducted to a temperature of between 400°C and 1200°C.
The method as claimed in any of claims 1 to 18, wherein the heating is carried out in a non-oxidizing atmosphere.
The method as claimed in any of claims 1 to 19, wherein the reducing agent comprises elemental carbon, preferably graphite, carbon black, or amorphous carbon.
The method as claimed in any of claims 1 to 20, wherein the reducing agent is present in the starting material in stoichiometric excess.
A product comprising carbon and an active material of formula

wherein a is greater than zero and less than or equal to 3, the sum of b plus c is greater than zero and up to 2, d is greater 0 and less than or equal to 3, MI comprises a metal or mixture of metals, Mil comprises a metal or mixture of metals, and at least one of MI and Mil comprises an element capable of an oxidation state higher than that initially present in the active material, wherein the active material is made by a process as claimed in any of claims 1 to 21, and the carbon is dispersed throughout the product.
A product comprising carbon and an active material of formula

wherein x is greater than or equal to 0.2 and less than or equal to 2, made by a process of any of claims 1 to 5, 12, 20, 21 and the carbon is dispersed throughout the product.

A product comprising carbon and an active material of formula

wherein a is greater than or equal to 0.2 and less than or equal to 2, b is greater than 0 and less than or equal to 1, and Mil comprises at least one metal selected from the group consisting of magnesium, calcium, and zinc, wherein the active material is made by a process as claimed in any of claims 1 to 21, and the carbon is dispersed throughout the product.
A product comprising carbon and an active material of formula

wherein a is greater than or equal to 0.2 and less than or equal to 2, b is greater than 0 and less than or equal to 1, made by a process of any of claims 1 to 21 and the carbon is dispersed throughout the product.
A battery comprising a positive electrode, a negative electrode and an electrolyte, wherein at least one electrode comprises an active material made by a process as claimed in any of claims 1 to 21.
The battery comprising a positive electrode, a negative electrode and an electrolyte, wherein at least one electrode comprises a product as claimed in claim 22.
The battery comprising a positive electrode, a negative electrode and an electrolyte, wherein at least one electrode comprises a product as claimed in claim 23.

The battery comprising a positive electrode, a negative electrode and an electrolyte, wherein at least one electrode comprises a product as claimed in claim 24.
The battery comprising a positive electrode, a negative electrode and an electrolyte, wherein at least one electrode comprises a product as claimed in claim 25.
A method for making a lithium mixed metal compounds, comprising the steps of:
a) providing starting material in particle form, the starting material comprising at least one metal and a reducing agent comprising carbon; combining the starting material particles to form a mixture; and heating the mixture for a time and at a temperature sufficient to reduce at least one metal of the starting material without full reduction to an elemental state to form a reduced metal compound;
b) reacting a lithium compound with the metal compound prepared as claimed in step a).
The method as claimed in claim 31, wherein the heating is carried out at a temperature of from 400°C to 1200°C.
The method as claimed in claims 31 or 32, wherein the lithium mixed-metal compound has the formula


greater than zero and up to 2, d is greater u and less than or equal to 3, Ml comprises a metal or mixture of metals, Mil comprises a metal or mixture of metals, and at least one of MI and Mil comprises an element capable of an oxidation state higher than that initially present in the active material.
The method as claimed in claim 33, wherein MI is selected from the group consisting of iron, cobalt, nickel, and mixtures thereof, and Mil is selected from the group consisting of calcium, magnesium, zinc and mixtures thereof
The method as claimed in claim 34, wherein MI comprises iron and Mil comprises magnesium.
The method as claimed in any of claims 31 to 35, wherein the reducing agent comprises elemental carbon, preferably graphite, carbon black, or amorphous carbon.
The method as claimed in any of claims 31 to 36, wherein the reducing agent is present in the starting material in stoichiometric excess.


Documents:

in-pct-2002-1089-che abstract-duplicate.pdf

in-pct-2002-1089-che abstract.pdf

in-pct-2002-1089-che assignment.pdf

in-pct-2002-1089-che claims-duplicate.pdf

in-pct-2002-1089-che claims.pdf

in-pct-2002-1089-che correspondence-others.pdf

in-pct-2002-1089-che correspondence-po.pdf

in-pct-2002-1089-che description (complete)-duplicate.pdf

in-pct-2002-1089-che description (complete).pdf

in-pct-2002-1089-che drawings-duplicate.pdf

in-pct-2002-1089-che drawings.pdf

in-pct-2002-1089-che form-1.pdf

in-pct-2002-1089-che form-13.pdf

in-pct-2002-1089-che form-19.pdf

in-pct-2002-1089-che form-26.pdf

in-pct-2002-1089-che form-3.pdf

in-pct-2002-1089-che form-5.pdf

in-pct-2002-1089-che others.pdf

in-pct-2002-1089-che pct.pdf

in-pct-2002-1089-che petition.pdf


Patent Number 218866
Indian Patent Application Number IN/PCT/2002/1089/CHE
PG Journal Number 23/2008
Publication Date 06-Jun-2008
Grant Date 16-Apr-2008
Date of Filing 16-Jul-2002
Name of Patentee VALENCE TECHNOLOGY, INC
Applicant Address
Inventors:
# Inventor's Name Inventor's Address
1 BARKER, Jeremy
2 SWOYER, Jeffrey, L
3 SAIDI, M., Yazid
PCT International Classification Number C01B25/37
PCT International Application Number PCT/US2000/035438
PCT International Filing date 2000-12-22
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 09/484,919 2000-01-18 U.S.A.