Process for synthesizing LixFeMZO4/ carbon and LixMZO4/ carbon composite materials

This application claims priority to: U.S. Provisional Patent Application No. 61/145,496, entitled: “PROCESS FOR SYNTHESIZING LixFeMZO4/CARBON AND LixMZO4/CARBON COMPOSITE MATERIALS”, inventors: Biying Huang, Xiongfei Shen and Yi-Qun Li, filed Jan. 16, 2009. This application is herein expressly incorporated by reference in its entirety.

This invention is in the general field of a processing method for preparing cathode materials for a secondary electrochemical cell.

In the rechargeable battery industry a variety of different cathode materials have been investigated. LiCoO 2 is the most common cathode material used today in commercial Li ion batteries, by virtue of its high working voltage and long cycle life. Although, LiCoO 2 is considered the cathode material of choice, the high cost, toxicity and relatively low thermal stability are features where the material has serious limitations as a rechargeable battery cathode. These limitations have stimulated a number of researchers to investigate methods of treating the LiCoO 2 to improve its thermal stability. However, the safety issue due to low thermal stability is still the critical limitation for LiCoO 2 cathode materials, especially when the battery is used in high charging-discharging rate conditions. Therefore, LiCoO 2 is not considered suitable as a cathode material in rechargeable batteries for transportation purposes and this has stimulated searches for alternative cathode material for use with electric vehicles and hybrid electric vehicles.

LiFePO 4 has been investigated as a very attractive alternative cathode material in rechargeable batteries due to its high thermal stability which makes it suitable for high rate charge-discharge applications in transportation devices and power tools. Batteries using LiFePO 4 as the cathode material have achieved market penetration in electric bicycles, scooters, wheel chairs and power tools.

Embodiments of the present invention are directed to cost effective methods of generating a composite active cathode of carbon and an ordered or modified olivine structure lithium iron phosphate based materials with superior electrochemical properties. Specific embodiments, as will be described below, are for use in a secondary electrochemical cell.

Most current LiFePO 4 materials still suffer from high impedance which will eventually limit the cycling life of a battery made from LiFePO 4 . The impedance of the materials is highly related to synthesis methods and formulation of the materials such as the replacement of Fe or carbon coating. In addition, most known methods such as solid state reaction suffer from the high cost of the starting materials such as iron oxalate and ammonium dihydrogen phosphate. In addition milling processes require long processing times and involve complicated processing procedures. Batteries using LiFePO 4 as the cathode material also have a limitation of the relatively low practical voltage range (2.0-4.1 V). The use of iron phosphate compounds as anode materials for Li rechargeable batteries has been reported (D. Son et al., “Nanoparticle iron-phosphate anode material for Li-ion battery,” Applied Physics Letters Volume 85, Number 24 (2004), pp. 5875-5877). The capacity of these synthesized nanoparticle iron phosphates was reported to be approximately three times higher than the ideal capacity of the LiFePO 4 cathode.

Therefore, the objective of this invention is to provide a method to synthesize ordered or modified olivine structure LiMZO 4 /carbon composite electrode material with low impedance and high performance, where M can be Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Zr, Nb, Mo, Ta, W, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu and other metal elements, and Z can be P, Si, S, Al, Ge, N, and V and other metalloid elements (hereinafter referred to as LMZO material).

In various embodiments of the invention, a cost effective process of generating a composite active electrode of LMZO material comprises reacting metal powder, such as iron, cobalt, manganese or mixtures thereof, with an aqueous based Z precursor, such as phosphorous pentoxide, silicone dioxide or a mixture thereof, drying the reaction intermediate, mixing the dried intermediate with a lithium precursor, adding a dopant, wherein the dopant is at least a M precursor, wherein the dopant is added when the metal powder is reacting with the Z precursor or after drying when the lithium precursor is being mixed and calcining the mixture in an inert or reducing environment under vacuum. In various embodiments of the invention, the metal powder is selected from the group consisting of metallic iron (Fe) powder, metallic cobalt (Co) powder, metallic manganese (Mn), metallic nickel (Ni) powder, and mixtures thereof. In various embodiments of the invention, Z is selected from the group consisting of P, Si, S, Al, Ge, N, and V elements and mixtures thereof, and the precursors of these elements can be P 2 O 5 , H 3 PO 4 , SiO 2 , H 2 SiO 3 , H 4 SiO 4 , NH 4 HSiO 3 , (NH 4 ) 2 SiO 3 , (NH4) 4-w H w SiO 4 (where w=0, 1, 2 or 3), H 2 SO 4 NH 4 HSO 4 , and (NH 4 ) 2 SO 4 In various embodiments of the invention, the lithium precursor is selected from the group consisting of a carbamate salt, a hydroxide salt and an acetate salt. In various embodiments of the invention, the dopant is in the form of a salt or a metal and is selected from the group consisting of Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Zr, Nb, Mo, Ta, W, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. In various embodiments of the invention, the dopant can be a carbon precursor. In various embodiments of the invention, the carbon precursor is added after drying before the lithium precursor is added and mixed or before the calcining step.

In various embodiments of the invention, the process further comprises adding an accelerator when the metal powder is reacting with the Z precursor wherein the accelerator is selected from the group consisting of O 2 , H 2 O 2 and Cl 2 . In various embodiments of the invention, the drying is carried out in the air at a temperature between a lower limit of approximately 1.5×10 2 ° K and an upper limit of approximately 7.5×10 2 ° K. In various embodiments of the invention, the carbon precursor is selected from the group consisting of carbon black, Super P® carbon, Super P Li™ carbon, one or more sugar molecules selected from the group consisting of monosaccharides, disaccharides and polysaccharides, including one or more sugar units selected from the group consisting of ribose, arabinose, xylose, lyxose, fructose, galactose, glucose and mannose, and one or more oxygen-carbon containing polymers selected from the group consisting of a polyether, a polyglycol, a polyester, polycaprolactone, polylactide, poly butylene succinate, poly butylene succinate adipate, polybutylene succinate terephthalate, poly-2-hydroxypropionate, poly-3-hydroxypropionate, poly-2-hydroxybutyrate, poly-3-hydroxybutyrate, poly-4-hydroxybutyrate, poly-3-hydroxyvalerate, poly-4-hydroxyvalerate, poly-5-hydroxyvalerate, poly-3-hydroxyhexanoate, poly-4-hydroxyhexanoate, poly-6-hydroxyhexanoate, poly-3-hydroxyoctanoate, poly-3-hydroxyphenylvaleric acid and poly-3-hydroxyphenylhexanoic acid.

In various embodiments of the invention, the calcination temperature is between a lower limit of approximately 7×10 2 ° K and an upper limit of approximately 1.2×10 3 K. In various embodiments of the invention, the simplified and cost efficient process of generating a composite active cathode of LMZO material comprises reacting metal powder with a phosphorous, silicon, or sulfur (Z=P, Si, S, Al, Ge, N, and V) precursor in an aqueous based solvent, drying the reaction intermediate, mixing the dried reaction intermediate with a lithium precursor and calcining the mixture in an inert or reducing environment under vacuum. During heating, the octahedral sites in a LMZO material can expand more than the tetrahedral sites when the M-O bond is weaker than the M-Z bonds (where O designates the octahedral ligand). As a result, carrying out reactions in a vacuum can allow the use of lower calcining temperatures.

FIG. 1 shows the X-ray diffraction pattern of (A) the sample synthesized in Example 1 and (B) the reference pattern for the olivine structure, LiFePO 4 according to an embodiment of the invention;

FIG. 2 shows a scanning electron micrograph image of the sample synthesized in Example 1 according to an embodiment of the invention at (A) a magnification 30,000× and (B) a magnification 5,000×;

FIG. 3 shows (A) the charging and (B) the discharging profile of an electrochemical cell with the sample synthesized in Example 1 according to an embodiment of the invention as the cathode;

FIG. 4 shows the cycling at 0.5 C charging and discharging rates of an electrochemical cell with the sample synthesized in Example 1 according to an embodiment of the invention as the cathode;

FIG. 5 shows the X-ray diffraction pattern of (A) the sample synthesized in Example 2 and (B) the reference pattern for the olivine structure, LiFePO 4 according to an embodiment of the invention;

FIG. 6 shows a scanning electron micrograph image of the sample synthesized in Example 2 according to an embodiment of the invention at (A) a magnification 30,000× and (B) a magnification 5,000×;

FIG. 7 shows the cycling at 0.5 C charging and discharging rates of an electrochemical cell with the sample synthesized in Example 2 according to an embodiment of the invention as the cathode;

FIG. 8 shows the X-ray diffraction pattern of (A) the sample synthesized in Example 3 according to an embodiment of the invention and (B) the reference pattern for the olivine structure, LiFePO 4 ;

FIG. 9 shows a scanning electron micrograph image of the sample synthesized in Example 3 according to an embodiment of the invention at (A) a magnification 30,000× and (B) a magnification 5,000×;

FIG. 10 shows (A) the charging and (B) the discharging profile of an electrochemical cell with the sample synthesized in Example 3 according to an embodiment of the invention as the cathode;

FIG. 11 shows the X-ray diffraction pattern of (A) the sample synthesized in Example 4 according to an embodiment of the invention and (B) the reference pattern for the olivine structure, LiFePO 4 ;

FIG. 12 shows a scanning electron micrograph image of the sample synthesized in Example 4 according to an embodiment of the invention at (A) a magnification 30,000× and (B) a magnification 5,000×;

FIG. 13 shows (A) the charging and (B) the discharging profile of an electrochemical cell with the sample synthesized in Example 4 according to an embodiment of the invention as the cathode;

FIG. 14 shows the X-ray diffraction pattern of (A) the sample synthesized in Example 5 according to an embodiment of the invention and (B) the reference pattern for the olivine structure, LiFePO 4 ;

FIG. 15 shows a scanning electron micrograph image of the sample synthesized in Example 5 according to an embodiment of the invention at (A) a magnification 30,000× and (B) a magnification 5,000×;

FIG. 16 shows (A) the charging and (B) the discharging profile of an electrochemical cell with the sample synthesized in Example 5 according to an embodiment of the invention as the cathode;

FIG. 17 shows the X-ray diffraction pattern of (A) the sample synthesized in Example 6 according to an embodiment of the invention and (B) the reference pattern for the olivine structure, LiFePO 4 ;

FIG. 18 shows a scanning electron micrograph image of the sample synthesized in Example 6 according to an embodiment of the invention at (A) a magnification 30,000× and (B) a magnification 5,000×; and

FIG. 19 shows (A) the charging and (B) the discharging profile of an electrochemical cell with the sample synthesized in Example 6 according to an embodiment of the invention as the cathode.

The following abbreviations are used: EC=ethylene carbonate; DI=de-ionized water; DMC=dimethyl carbonate; PVDF=polyvinylidene fluoride; RT=room temperature; XRD=x-ray diffraction.

The invention is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to ‘an’ or ‘one’ embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. In the following description, various aspects of the present invention will be described. However, it will be apparent to those skilled in the art that the present invention may be practiced with only some or all aspects of the present invention. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the present invention. Parts of the description will be presented in chemical synthesis terms, such as precursors, intermediates, product, and so forth, consistent with the manner commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. As well understood by those skilled in the art, these are labels, and may otherwise be manipulated through synthesis conditions. Various operations will be described as multiple discrete steps in turn, in a manner that is most helpful in understanding the present invention, however, the order of description should not be construed as to imply that these operations are necessarily order dependent. Various embodiments will be illustrated in terms of exemplary classes of precursors. It will be apparent to one skilled in the art that the present invention can be practiced using any number of different classes of precursors, not merely those included here for illustrative purposes. Furthermore, it will also be apparent that the present invention is not limited to any particular mixing paradigm.

Definitions: a secondary battery is a rechargeable battery, also known as a storage battery, is a group of two or more secondary cells. Reaction is a process in which one or more substances are changed into others. Olivine is a mostly close packed hexagonal array of oxygen anions, with a metalloid group (ZO 4 ) occupying ⅛ of the tetrahedral sites, and the metal cations (M) occupying ½ of the octahedral sites, and two distinct octahedral sites designated O1 and O2, where O2 is slightly larger and slightly more distorted than O1. Ordered is a crystal structure where the atoms of different elements seek preferred lattice positions. Composite materials are engineered materials made from two or more constituent materials with significantly different physical or chemical properties of the reactants and which remain separate and distinct on a macroscopic level within the finished structure. Phase is a distinct state of matter in a system. Drying is a mass transfer process resulting in the removal of water moisture or moisture from another solvent, by evaporation from a solid, semi-solid or liquid (hereafter product) to end in a solid state. Adding is to join or combine or unite with other ingredients. Mixing is a unit operation that involves manipulating a heterogeneous physical system, with the intent to make it more homogeneous and defines steps to allow the constituent molecules from two or more ingredients in the heterogeneous system to become physically proximal or in contact. Blending defines the mixing of two or more compounds to allow the constituent molecules from the two or more compounds to become physically proximal or in contact. Grinding defines the use of use of a mortar and pestle to break up a compound into smaller pieces resulting in physically cleaving chemical and/or physical bonds within the compound. Milling defines the use of machinery with a rotating tool to break up a compound into smaller pieces resulting in physically cleaving chemical and/or physical bonds within the compound. Dry Milling refers to grinding of compounds in the absence of a liquid and in which the presence of water in the compound does not result in the accumulation of visually detectable water molecules on the surface of the compound. A Ball Mill is a type of grinder. It is a cylindrical device used in grinding or mixing of materials. Ball mills rotate around a horizontal axis, partially filled with the material to be ground plus the grinding media. Different materials are used as the grinding media including ceramic balls. An internal cascading effect reduces the material to a fine powder. Wet Slurry Milling refers to milling solid compound in the presence of a liquid, solution, suspension or colloid. A Wet Ball Mill Slurry refers to a ball mill in which the material is present together with a liquid, solution, suspension or colloid and the grinding media. Homogeneous slurry refers to the final state of a heterogeneous precursor system with two or more solid compounds, wherein the two or more compounds are distributed evenly in a liquid physical system, wherein analysis of any portion of the whole liquid physical system reveals equal amounts of the compounds making up the entire heterogeneous precursor system. A Sol Gel Slurry uses a colloidal solution, gelation and solvent removal techniques to prepare mixtures of inorganic solid composite materials from liquids. A Colloidal solution can be prepared by controlled precipitation and peptisation of inorganic precursors or by hydrolysis and poly-condensation of metallic alkoxides. A metal or a “native metal” is a metal element in the zero oxidation state. Metal powder is a metal element in a physical powder state.

The performance of battery materials is highly dependent on the morphology, particle size, purity, and conductivity of the materials. Different material synthesis processes can readily produce materials with different morphology, particle size, purity, or conductivity. As a result, the performance of the battery materials is highly dependent on the synthesis process.

In order to improve the rechargeable battery performance and reduce the synthesis and production costs, different processing methods have been explored to synthesize LiFePO 4 type materials. Currently, the dominant production method is the ball mill method and using iron oxalate as a precursor. However, the processing cost of this method is very high especially due to the high cost of iron oxalate. In addition, as metal doping is needed, for example to control discharge voltage and improve conductivity, the ball mill method usually mixes dopant metal precursor(s) with iron oxalate. This kind of solid state mixing cannot achieve a homogeneous mixing of the dopant with other precursors. As a result, the quality and performance of the synthesized materials is negatively affected. These factors significantly limit the market for lithium electrodes synthesized using the ball mill production method.

For most current methods, the final calcination to achieve LMZO material phase is carried out with conventional furnace heating which requires longer calcinations time such as few hours to over 12 hours. In this conventional heating method, because of relatively long heating time, significant particle aggregation can result. In addition, conventional heating methods result in increased energy consumption and thus increased cost.

The safety issue of LiCoO 2 cathode materials and the high cost of reactants in the conventional method of producing the LiFePO 4 type materials significantly limit the available market for Li ion rechargeable batteries. This situation is exacerbated by the pursuit of low production cost means of manufacturing LiFePO 4 materials.

In various embodiments of the invention, metal powder is used as the precursor to generate LMZO material, such as LiFePO 4 , LiCoPO 4 . This can be very attractive as it can produce high performance materials with low cost. This is essentially because of the low cost of metal powder, such as Fe and Co metals compared to their salts or oxides, such as iron oxalate and cobalt oxide. Known methods for generating FePO 4 or LiFePO 4 have many processing steps. The numerous processing steps result in a high production cost. In addition, the numerous processing steps make it difficult for fine control. In addition, when iron metal powder is used, it is necessary to have a process to completely dissolve and react the iron powder. If the process does not insure complete dissolution and thereby reaction of the iron powder, iron powder residue is readily observed in the resulting product. The presence of even minute amounts of iron in an electrode will reduce the capacity and cycle life of the electrode material. These problems are present in the previously reported processes to produce LiMPO 4 type materials. Further, no process has been developed to address the reduced capacity and cycle life of inhomogeneous cathode materials. In an embodiment of the present invention, microwave calcinations can be used in a process to synthesize LiFePO4 olivine phase compounds to significantly reduce the processing time and cost.

In various embodiments of the invention, a simplified and cost efficient process to synthesize LMZO material can be accomplished by using metal powder and at least one compound selected from the group consisting of P 2 O 5 , H 3 PO 4 , SiO 2 , H 2 SiO 3 , H 4 SiO 4 , NH 4 HSiO 3 , (NH 4 ) 2 SiO 3 , (NH4) 4-w H w SiO 4 (where w=0, 1, 2, or 3), H 2 SO 4 NH 4 HSO 4 , and (NH 4 ) 2 SO 4 Al 2 O 3 , Al(OH) 3 , AlNH 4 (SO 4 ) 2 , GeSe 2 , GeO, GeO 2 , Ge 2 O 3 , Ge 2 O 7 , SiGeO 2 , HNO 3 , NH 3 , Q 3 N 2 (where Q is a divalent metal), R 3 N (where R is a monovalent metal), V 2 O 3 , VO 2 , VO, V 2 O 5 , VOSO 4 , NaVO 3 , and Na 3 VO 4 as the precursors. In the general formula Li x MZO 4 , where 0<x≦1, M is at least one metal selected from one of the following groups: (i) a 1 st row transition metal, (ii) Al, Ga, Si, Ge, Mg, Ca, Sr, (iii) Zr, Nb, Ta, Mo, W and (iv) a rare earth metal, and Z is at least one element selected from the group consisting of P, Si, S, Al, Ge, N, and V. In an embodiment of the invention, a simplified process synthesizes pure LiMPO 4 , where M is Fe, Mn, Co, or Ni. In an embodiment of the invention, a simplified process synthesizes LiMPO 4 , where M is at least one metal. In an embodiment of the invention, a simplified process synthesizes LiMZO 4 , where M is at least one metal, Z is P 1-m-n-q-r-t-u Si m , S n Al q Ge r N t V u and 0≦m, n, q, r, t, u≦1. A major advantage of this invention is the low cost due to simplified process with use of metal powder as precursor. This process is suitable for mass production of cathode material. In addition, the process can produce homogeneous pure metal and mixed metal LiMPO 4 because it involves the co-dissolution of metal precursors to form a homogeneous slurry.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metal powder with at least one from P, Si, S, Al, Ge, N, and V precursor in an aqueous based solvent, drying the reaction, mixing the dried reaction with a lithium precursor and calcinating the mixture with heating in an inert or reducing environment under vacuum. In various embodiments of the invention, heating includes one or more of convection heating, conduction heating and microwave heating.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metallic metal powder with at least one ZO 4 precursor where Z is selected from P, Si, S, Al, Ge, N, and V and the ZO 4 precursor can be selected from the group consisting of P 2 O 5 , NH 4 H 2 PO 4 , (NH4) 2 HPO4, H 3 PO 4 , SiO 2 , H 2 SiO 3 , H 4 SiO 4 , NH 4 HSiO 3 , (NH 4 ) 2 SiO 3 , (NH4) 4-w H w SiO 4 (where w=0, 1, 2, or 3), H 2 SO 4 NH 4 HSO 4 , and (NH 4 ) 2 SO 4 Al 2 O 3 , Al(OH) 3 , AlNH 4 (SO 4 ) 2 , GeSe 2 , GeO, GeO 2 , Ge 2 O 3 , Ge 2 O 7 , SiGeO 2 , HNO 3 , NH 3 , Q 3 N 2 (where Q is a divalent metal), R 3 N (where R is a monovalent metal), V 2 O 3 , VO 2 , VO, V 2 O 5 , VOSO 4 , NaVO 3 , and Na 3 VO 4 in an aqueous based solvent, drying the reaction, mixing the dried reaction with a lithium precursor and calcining the mixture with heating in an inert or reducing environment under vacuum.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metallic metal powder with at least one from P, Si, S, Al, Ge, N, and V precursor in an aqueous based solvent, drying the reaction, mixing the dried reaction with a lithium precursor selected from the group consisting of a carbamate salt, a hydroxide salt and an acetate salt and calcining the mixture with heating in an inert or reducing environment under vacuum.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metal powder with at least one from P, Si, S, Al, Ge, N, and V precursor in an aqueous based solvent, drying the reaction, mixing the dried reaction with a lithium precursor, adding a dopant either during the reaction between the metal(s) and P, Si, S, Al, Ge, N, and V or before the mixing step and calcining the mixture with heating in an inert or reducing environment under vacuum.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metal (M) powder with at least one ZO 4 precursor where Z is selected from P, Si, S, Al, Ge, N, and V and the ZO 4 precursor can be selected from the group consisting of P 2 O 5 , H 3 PO 4 , SiO 2 , H 2 SiO 3 , H 4 SiO 4 , NH 4 HSiO 3 , (NH 4 ) 2 SiO 3 , (NH4) 4-w H w SiO 4 (where w=0, 1, 2 or 3), H 2 SO 4 NH 4 HSO 4 , (NH 4 ) 2 SO 4 Al 2 O 3 , Al(OH) 3 , AlNH 4 (SO 4 ) 2 , GeSe 2 , GeO, GeO 2 , Ge 2 O 3 , Ge 2 O 7 , SiGeO 2 , HNO 3 , NH 3 , Q 3 N 2 (where Q is a divalent metal), R 3 N (where R is a monovalent metal), V 2 O 3 , VO 2 , VO, V 2 O 5 , VOSO 4 , NaVO 3 , and Na 3 VO 4 in an aqueous based solvent, drying the reaction, mixing the dried reaction with a lithium precursor, adding a dopant either during the reaction between the metal and Z precursor or before the mixing step and calcining the mixture with heating in an inert or reducing environment under vacuum.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metallic iron powder with a phosphorous precursor in an aqueous based solvent, drying the reaction, mixing/milling the dried reaction with a lithium precursor selected from the group consisting of a carbonate salt, a hydroxide salt and an acetate salt, adding a dopant either during the reaction between the iron and phosphorous or before the mixing step and calcining the mixture with heating in an inert or reducing environment under vacuum.

In an embodiment of the invention, a method of producing LMZO active electrode material for secondary battery comprises reacting metallic (M) powder with a ZO 4 precursor in an aqueous based solvent, drying the reaction, mixing the dried reaction with a lithium precursor, adding a dopant either during the reaction between the metal powder and at least one ZO 4 precursor where Z is selected from P, Si, S, Al, Ge, N, and V or before the mixing step wherein the dopant is selected from the group consisting of a 1st row transition metal, Al, Ga, Si, Ge, Mg, Ca, Sr, Zr, Nb, Ta, Mo, W and a rare earth metal, and calcining the mixture with heating in an inert or reducing environment under vacuum.

In an embodiment of the invention, a reaction accelerator selected from the group consisting of O 2 , H 2 O 2 , Cl 2 , and HClO 4 , can be used to accelerate the reaction between the metal powder and the Z precursor.

In an embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture.

In an alternative embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein the M precursor is one or more of a powder and the M precursor added to ZO 4 is selected from the group consisting of Fe, Co, Ni, and Mn.

In another embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein Z is one or more of either phosphorous and the PO 4 precursor is selected from the group consisting of P 2 O 5 and H 3 PO 4 ; silicon and the SiO 4 precursor is selected from the group consisting of SiO 2 , H 2 SiO 3 , H 4 SiO 4 , NH 4 HSiO 3 , (NH 4 ) 2 SiO 3 and (NH4) 4-w H w SiO 4 (where w=0, 1, 2 or 3); sulfur and the SO 4 precursor is selected from the group consisting of H 2 SO 4 , NH 4 HSO 4 , and (NH 4 ) 2 SO 4 ; aluminum and the AlO 4 precursor is selected from the group consisting of Al 2 O 3 , Al(OH) 3 and AlNH 4 (SO 4 ) 2 ; germainum and the GeO 4 precursor is selected from the group consisting of GeSe 2 , GeO, GeO 2 , Ge 2 O 3 , Ge 2 O 7 and SiGeO 2 ; nitrogen and the NO 4 precursor is selected from the group consisting of HNO 3 , NH 3 , Q 3 N 2 (where Q is a divalent metal) and R 3 N (where R is a monovalent metal) and vanadium and the GeO 4 precursor is selected from the group consisting of V 2 O 3 , VO 2 , VO, V 2 O 5 , VOSO 4 , NaVO 3 , and Na 3 VO 4 .

In a different embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein one or both of the dopant is the same as the M precursor reacted the ZO 4 precursor and the dopant referred is added to the lithium precursor.

In another embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, further comprising adding an accelerator to the M precursor and ZO 4 precursor, wherein the accelerator is selected from the group consisting of O 2 , H 2 O 2 , HClO 4 , and Cl 2 .

In an alternative embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein one or more of the reaction between M precursor and the ZO 4 precursor occurs in a wet ball mill slurry, the drying step after M precursor and the ZO 4 precursor have reacted is carried out in air and the mixing with the lithium precursor includes one or more of grinding, milling and blending.

In a varying embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture wherein one or more of the drying after M precursor and the ZO 4 precursor have reacted is carried out at a temperature between a lower limit of approximately 1.5×10 2 ° K and an upper limit of approximately 7.5×10 2 ° K, the lithium precursor is selected from the group consisting of a carbamate salt, a hydroxide salt and an acetate salt, and wherein the carbon is uniformly dispersed throughout the composite material produced.

In another embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein the dopant added is one or more of a metal, a salt, an oxide, and selected from the group consisting of Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Zr, Nb, Mo, Ta, W, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

In various embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein the carbon precursor is one or more of added before one or both the mixing with the lithium precursor and the calcining step, selected from the group consisting of carbon black, Super P carbon and Super P Li carbon, selected from one or more sugar molecules selected from the group consisting of monosaccharides, disaccharides and polysaccharides, including one or more sugar units selected from the group consisting of ribose, arabinose, xylose, lyxose, fructose, galactose, glucose and mannose and selected from one or more oxygen and carbon containing polymers selected from the group consisting of one or more of polyether, polyglycol, polyester, polyethylene, poly(halogen)ethylene (where polyhalogen ethylene includes polyfluoroethylene and polychoroethylene), polypropylene, polyvinylidene halogen, polymethylmethacrylate, polyacrylonide, polycaprolactone, polylactide, poly butylene succinate, polybutylene succinate adipate, polybutylene succinate terephthalate, poly-hydroxypropionate, poly-hydroxybutyrate, poly-hydroxyvalerate, poly-hydroxyhexanoate, poly-3-hydroxyoctanoate, poly-3-hydroxyphenylvaleric acid and poly-3-hydroxyphenylhexanoic acid.

In a different embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein the calcination is carried out with one or more conditions selected from the group consisting of an inert environment, a reducing environment, under vacuum, using microwave heating, using convection heating, using conduction heating and wherein the calcining temperature is between a lower limit of approximately 7×10 2 ° K and an upper limit of approximately 1.2×10 3 ° K.

In another embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M has an oxidation state less than one, wherein Z is selected from the group consisting of P, Si, S, Al, Ge, N, V; drying the reaction, mixing the dried reaction with a lithium precursor, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element and calcining the doped mixture, wherein the calcination is carried out with two or more conditions selected from the group consisting of an inert environment, a reducing environment, under vacuum, using microwave heating, using convection heating, using conduction heating and wherein the calcining temperature is between a lower limit of approximately 7×10 2 ° K and an upper limit of approximately 1.2×10 3 ° K.

In an alternative embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M is a metal element and Z is selected from the group consisting of P, Si, S, Al, Ge, N, and V, drying the reaction, mixing the dried reaction with a lithium precursor, milling the mixture in a ball mill, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element, wherein the dopant is not the M precursor reacted with the ZO 4 precursor and calcining the doped mixture in an inert or reducing environment.

In an alternative embodiment of the invention, a method of producing a LMZO comprising reacting at least one M precursor with at least one ZO 4 precursor in an aqueous based solvent, wherein M is a metal element and Z is selected from the group consisting of P, Si, S, Al, Ge, N, and V, drying the reaction, mixing the dried reaction with a lithium precursor, milling the mixture in a ball mill, adding one or both a dopant and a carbon precursor to the mixture, wherein the dopant is at least a M precursor, wherein M is a metal element, wherein the dopant is not the M precursor reacted with the ZO 4 precursor and calcining the doped mixture in an inert or reducing environment, wherein the M precursor reacted with ZO 4 precursor is one or more of in a metallic form with an oxidation state of zero, a powder and selected from the group consisting of Fe, FeO, Fe 2 O 3 , Fe 3 O 4 , Fe 2 O 5 , Co, CoO, Co 2 O 3 , Co 3 O 4 , Ni, NiO, Ni 2 O 3 , NiO 2 H, Mn, MnO, MnO 2 , Mn 2 O 3 , MnO 3 , MnO 6 , Mn 2 O 7 , Mn 3 O 4 and Mn 5 O 8 .

Previous Process

Previously, it has been shown that FeC 2 O 4 +LiCO 3 +NH 4 H 2 PO 4 can be reacted to form LiFePO 4 . However the cost of the many of the reagents and in particular the FeC 2 O 4 and the NH 4 H 2 PO 4 is high. Alternatively, it has been shown that FePO 4 +LiCO 3 can be reacted to form LiFePO 4 . However, the reaction between FePO 4 and LiCO 3 does not produce a homogeneous material. Further, the reaction can be difficult to control when carried out to produce material with reduced particulate size. Finally, LiFePO 4 synthesized from FePO 4 +LiCO 3 results in micro particles rather than nano particles sizes.