WO2025188892A1

WO2025188892A1 - Process for conversion of products into useful cathode materials

Info

Publication number: WO2025188892A1
Application number: PCT/US2025/018572
Authority: WO
Inventors: Russell Pratt; Bree PHELPS; Danien SCIPIO; Peter CSERNICA; Wesley MICHAELS; Chirranjeevi Gopal
Original assignee: Mitra Future Technologies Inc
Current assignee: Mitra Future Technologies Inc
Priority date: 2024-03-05
Filing date: 2025-03-05
Publication date: 2025-09-12
Anticipated expiration: 2026-09-05
Also published as: WO2025188892A8

Abstract

Embodiments of the present invention relate to olivine-type cathode materials useful in lithium-ion batteries. More specifically, embodiments of the present invention comprise methods for the application of carbon coatings to oxidized olivine-type lithium-transition metal-phosphate (LMP) products synthesized using various synthesis routes.

Description

Docket No.113544-838846 PROCESS FOR CONVERSION OF PRODUCTS INTO USEFUL CATHODE MATERIALS CROSS-REFERENCE [0001] The present patent application claims the benefit of priority to a Provisional Patent Application Serial No.63/561,665, entitled “Process for Conversion of Products into Useful Cathode Materials,” filed on March 05, 2024, which is incorporated herein by reference in its entirety. TECHNICAL FIELD [0002] The present invention relates to synthesis of olivine-type cathode materials useful in lithium-ion bateries. More specificaly, the present invention relates to in-situ carbon coating olivine-type lithium- transition metal-phosphate (LMP) products, resulting in a reduction of oxidized impurities in the LMP product. BACKGROUND [0003] Lithium-ion bateries are the most promising portable energy source in electronic devices, including electric vehicles and hybrid electric vehicles, because of their high working voltage, high energy density, and good cyclic performance. In these bateries, olivine-type cathode materials such as LiMPO4 (M=Fe and Mn) have atracted significant interest, as LiMPO4 has low cost and high intrinsic safety. The olivine-type cathode materials can be synthesized by various methods including, but and not limited to, fusion synthesis, hydrothermal synthesis, solid state synthesis, melt synthesis, and similar methods. Numerous atempts have been made to enhance the electrochemical properties of the olivine-type cathode materials synthesized by these methods known in the art, including particle-size reduction, cation doping, and/or carbon coating. Nevertheless, the olivine-type cathode materials synthesized by these methods may typicaly retain oxidized byproducts if the atmosphere is not sufficiently reducing during the synthesis process. Such an atmosphere routinely arises from, for example, insufficient carbon addition in solid-state synthesis, or partial or complete cooling in an oxidizing atmosphere in fusion or solid-state synthesis method. In addition, even if pure, the olivine-type cathode materials synthesized by these methods require further processing, for example, they must be reduced to sub-micron length scales. [0004] As noted above, olivine-type cathode materials synthesized by the methods available in the art are inefficient, for example, these methods tend to produce cathode materials with oxidized impurities which require further processing. BRIEF SUMMARY 1 102268356.1 Docket No.113544-838846 [0005] Provided herein, inter alia, is a method for decreasing oxidation impurities in an olivine-type lithium-transition metal-phosphate (LMP) material. Also provided herein are olivine-type cathode materials having a decreased oxidized impurity profile. [0006] In a first aspect, the method includes dry miling particles of the olivine-type LMP material to obtain a dry miled LMP powder. The olivine-type LMP material further includes oxidation impurities. It further includes, adding a carbon-containing compound to the dry miled LMP powder to form a mixture. The method further includes, miling the LMP material and the carbon-containing compound mixture with a liquid medium to form a wet-miled slurry. The method additionaly includes drying the wet-miled slurry to yield primary particles comprising particles of the olivine-type LMP material and the carbon-containing compound. The primary particles have a d50 ranging from about 50 nm to about 5000 nm. Further, the method includes calcining the primary particles to produce carbon-coated secondary particles comprising LMP having a d50 ranging from about 50 nm to about 5000 nm. In an embodiment, the LMP in the secondary particles has a decreased oxidation impurity content. [0007] In an aspect, the LMP is a compound having the formula: Li1+x1(M)x2PO4,wherein M is one or more of Fe and Mn; x1 is 0-0.1; and x2 is 0.8-1.0. [0008] In an embodiment, the LMP compound further comprises a dopant (A) having the formula: Li1+x1(MA)x2PO4,wherein M is one or more of Fe and Mn; x1 is 0.0-0.1; x2 is 0.8-1.0; and Ais one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0009] In another aspect, the LMP compound has the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4,wherein x1 is 0.0-0.1; x2 is 0.9-1.0; y is 0.5-0.8; z is 0.0-0.1 and A is one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0010] In another aspect, the LMP compound has the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4,wherein x1 is 0.01-0.06; x2 is 0.9-1.0; y is 0.6-0.7; z is 0.0-0.05 and A is one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0011] In an embodiment, the LMP compound may have the formula: LixMyPO4,wherein M is one or more of Fe, Ti and Mg; x is 0.9-1.1; and y is 0.9-1.0. [0012] In some other embodiments, the LMP compound may have the formula: LixFeyAzPO4,wherein x is 0.99-1.02; y is 0.96-1.0; z is 0.00-0.03 and A is one or more of Ti and Mg. [0013] In an aspect, the carbon-containing compound is selected from the group consisting of glucose, sucrose, lactose, maltodextrin, soluble starch, polyethylene glycol, vinyl alcohol, acrylic acid, citric acid, oxalic acid, lauric acid, urea, and combinations thereof. 2 102268356.1 Docket No.113544-838846 [0014] In another aspect, the method further includes formulating a cathode sheet using the secondary particles; wherein the secondary particles have a d50 ranging from about 100 nm to about 1000 nm. In an aspect, the dry miled LMP powder has a d50 of less than or equal to 10 µm. In another aspect, the dry miled LMP powder has a d50 ranging from about 400 nm to about 800 nm. [0015] In an embodiment, the carbon-coated secondary particles have a d50 ranging from about 100 nm to about 300 nm. In another embodiment, the LMP in the secondary particles has an oxidation impurity content of less than or equal to 1% by weight. In another embodiment, the LMP in the secondary particles has an oxidation impurity content of less than or equal to 0.1% by weight. In another embodiment, the oxidation impurities are present in an amount of greater than 5% by weight. [0016] In some embodiments, the liquid medium comprises an organic solvent selected from methanol, ethanol, isopropanol, 2-butanol, acetone, 2-butanone, and combinations thereof. In an embodiment, the liquid medium is water. [0017] In an aspect, the wet-miled slurry is dried by a process of spray drying, air drying, or vacuum drying. In another aspect, the wet-miled slurry is spray dried with an inlet temperature of about 160 °Cand an outlet temperature of about 105 °C. [0018] In an embodiment, the calcining occurs at a temperature of about 700° C. In another embodiment, the calcining occurs for about 1 hour. [0019] In another aspect of the invention, a method for decreasing oxidation impurities in an olivine-type lithium-transition metal-phosphate (LMP) material is provided herein. The method includes dry miling particles of the olivine-type LMP material to obtain a dry miled LMP powder, wherein the olivine-type LMP material comprises oxidation impurities in an amount of greater than 5% by weight. In an aspect the method further includes adding a carbon-containing compound to form a mixture with the LMP, wherein the carbon-containing compound is selected from the group consisting of glucose, sucrose, lactose, maltodextrin, soluble starch, polyethylene glycol, vinyl alcohol, acrylic acid, citric acid, oxalic acid, lauric acid, urea, and combinations thereof. Further, the method includes miling the LMP and carbon-containing compound mixture with a liquid medium to form a wet-miled slurry. In another embodiment, the method further includes drying the wet-miled slurry to yield primary particles comprising particles of the olivine- type LMP material and the carbon-containing compound; wherein the primary particles have a d50 ranging from about 50 nm to about 5000 nm. In another embodiment, the method includes calcining the primary particles to produce carbon-coated secondary particles having a d50 ranging from about 50 nm to about 5000 nm; wherein the LMP in the secondary particles has a decreased oxidation impurity content of less than 1% by weight. 3 102268356.1 Docket No.113544-838846 [0020] In an aspect, the LMP is a compound having the formula: Li1+x1(M)x2PO4,wherein M is one or more of Fe Mn, Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, Na; x1 is 0-0.1; and x2 is 0.8-1.0. [0021] In an embodiment, the LMP compound further comprises a dopant (A) having the formula: Li1+x1(MA)x2PO4,wherein M is one or more of Fe and Mn; x1 is 0.0-0.1; x2 is 0.8-1.0; and Ais one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0022] In another aspect, the LMP compound has the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4,wherein x1 is 0.0-0.1; x2 is 0.9-1.0; y is 0.5-0.8; z is 0.0-0.1 and A is one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0023] In another aspect, the LMP compound may have the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4,wherein x1 is 0-0.1; x2 is 0.9-1.0; y is 0.5-0.8; z is 0.0-0.1 and A is one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0024] In another aspect, the LMP compound has the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4,wherein x1 is 0.01-0.06; x2 is 0.9-1.0; y is 0.6-0.7; z is 0.0-0.05 and A is one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. [0025] In some embodiments, the LMP compound has the formula: LixMyPO4,wherein M is one or more of Fe, Ti, and Mg; x1 is 0.9-1.1; and y is 0.9-1.0. [0026] In some other embodiments, the LMP compound has the formula: LixFeyAzPO4,wherein x1 is 0.99-1.02; y is 0.96-1.0; z is 0.00-0.03 and A is one or more of Ti and Mg. BRIEF DESCRIPTION OF FIGURES [0027] FIG.1 is a representative XRD (X-ray diffractogram) patern of a LMFP product as synthesized herein; the XRD diffractogram shows phase-pure LMFP with no residual oxidized impurities; [0028] FIG.2 demonstrates the specific capacity of cels manufactured by using the cathode as described herein; these cels indicated discharge capacity of 149 mAh/g at C/5 and 136 mAh/g at 1C when cycled from 2.5-4.4V; [0029] FIG.3 is a representative XRD patern of a LMFP product as synthesized herein; the XRD diffractogram shows phase-pure LMFP with no residual oxidized impurities; [0030] FIG.4 is a representative XRD patern of a LMFP product as synthesized herein; the XRD diffractogram shows phase-pure LMFP with no residual oxidized impurities; [0031] FIG.5 is a representative XRD patern of a LMFP product as synthesized herein; the XRD diffractogram shows phase-pure LMFP with no residual oxidized impurities; 4 102268356.1 Docket No.113544-838846 [0032] FIG.6 is a representative XRD patern of a LMFP product as synthesized herein; the XRD diffractogram shows phase-pure LMFP with no residual oxidized impurities; [0033] FIG.7 demonstrates the specific capacity of cels manufactured by using the cathode as described herein; these cels indicated discharge capacity discharge capacity of 113 mAh/g at C/5 when cycled from 2.5-4.4V; [0034] FIG.8 is a representative XRD patern of a LMFP product as synthesized herein; the XRD diffractogram shows phase-pure LMFP with no residual oxidized impurities; [0035] FIG.9 demonstrates the specific capacity of cels manufactured by using the cathode as described herein; these cels indicated discharge capacity discharge capacity of 113 mAh/g at C/5 when cycled from 2.5-4.4V; [0036] FIG.10 is a representative XRD patern of a LFP product as synthesized herein; the XRD diffractogram shows phase-pure LFP with no residual oxidized impurities; and [0037] FIG.11 demonstrates the specific capacity of cels manufactured by using the cathode as described herein; these cels indicated discharge capacity discharge capacity of 158 mAh/g at C/25 and 148 mAh/g at 1C when cycled from 2.5-3.8V. DETAILED DESCRIPTION [0038] Generaly provided herein inter alia, are methods to make cathode materials with decreased oxidation impurities using an olivine-type lithium-transition metal-phosphate (LMP) material. Also provided herein is a method for application of carbon coatings to fused olivine-type material. Further, the methods described herein alow the use of oxidized starting material to make cathode materials. Overal, the resultant LMP exhibits improved discharge capacities. [0039] In particular, the instant invention provides a method for decreasing oxidation impurities in an olivine-type lithium-transition metal-phosphate (LMP) material. The method includes a number of steps. Firstly, particles of the olivine-type LMP material undergo dry miling to obtain a dry miled LMP powder. The olivine-type LMP material as described herein includes oxidation impurities. The method further includes adding a carbon-containing compound to the dry miled LMP powder to form a mixture. Next, the mixture including the LMP material and the carbon-containing compound is miled further with a liquid medium to form a wet-miled slurry. Furthermore, the wet-miled slurry is dried to yield primary particles. The primary particles further comprise the olivine-type LMP material, and the carbon-containing compound and the primary particles have a d50 ranging from about 50 nm to about 5000 nm. Next, the method includes calcining the primary particles to produce carbon coated secondary particles. The secondary particles include LMP material having a d50 ranging from about 50 nm to about 5000 nm and the secondary particles has a reduced oxidation impurity content. 5 102268356.1 Docket No.113544-838846 [0040] The olivine-type lithium-transition metal-phosphate (LMP) material as used herein may have a compound having a formula of Li1+x1(M)x2PO4. In the formula, x1 may range from about 0 to about 0.1. Specificaly, x1 may be about 0.0 to about 0.09, about 0.0 to about 0.08, about 0.0 to about 0.07, about 0.0 to about 0.06, about 0.01 to about 0.08, about 0.01 to about 0.06, about 0.02 to about 0.08 or about 0.02 to about 0.06, about 0.02 to about 0.06, or about 0.01 to about 0.06. Further, in the above formula, x2 may range from about 0.8 to about 1.5. More specificaly, x2 may be about 0.6 to about 1.5, about 0.6 to about 1.4, about 0.8 to about 1.4, about 0.9 to about 1.3, about 0.9 to about 1.5, about 0.8 to about 1.2, about 0.9 to about 1.2, about 0.9 to about 1.1, about 0.9 to about 1.0, about 0.8 to about 1.0, about 0.8 to about 0.9, about 0.9 to about 0.98, about 0.95 to about 1.0, about 0.91 to about 1.0, about 0.92 to about 1.0, about 0.94 to about 1.0, or about 0.96 to about 1.0. [0041] The transition metal (M) of the LMP material with a formula Li1+x1(M)x2PO4 may include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Cd or combination thereof. In an embodiment, M is one or more of: Fe or Mn. [0042] In an embodiment, the LMP compound has a formula of, Li1+x1(M)x2PO4,whereinx1 is about 0.00 to about 0.1, x2 is about 0.8 to about 1.0, and M is one or more of: Mn or Fe. [0043] Alternatively, the olivine-type lithium-transition metal-phosphate (LMP) material may have a compound having a formula of Li1+x1(MA)x2PO4. In the formula, x1 may range from about 0.0 to about 0.1. More specificaly, x1 may range from about 0.0 to about 0.09, about 0.0 to about 0.08, about 0.0 to about 0.07, about 0.0 to about 0.06, about 0.01 to about 0.08, about 0.01 to about 0.06, about 0.02 to about 0.08 or about 0.02 to about 0.06, about 0.02 to about 0.06, or about 0.01 to about 0.06. Further, in the above formula, x2 may range from about 0.8 to about 1.5. More specificaly, x2 may range from about 0.6 to about 1.5, about 0.6 to about 1.4, about 0.8 to about 1.4, about 0.9 to about 1.3, about 0.9 to about 1.5, about 0.8 to about 1.2, about 0.9 to about 1.2, about 0.9 to about 1.1, about 0.9 to about 1.0, about 0.8 to about 1.0, about 0.8 to about 0.9, about 0.9 to about 0.98, about 0.95 to about 1.0, about 0.91 to about 1.0, about 0.92 to about 1.0, about 0.94 to about 1.0, or about 0.96 to about 1.0. [0044] In addition, the transition metal (M) of the LMP material with a formula Li1+x1(MA)x2PO4 may include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Cd or combination thereof. Further, the variable A may be one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na or combination thereof. In an embodiment, M is one or more of: Fe or Mn. [0045] In an embodiment, the LMP compound has a formula of, Li1+x1(MA)x2PO4,whereinx1 is about 0.00 to about 0.1, x2 is about 0.8 to about 1.0, A is one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, or Na and M is one or more of: Mn or Fe. 6 102268356.1 Docket No.113544-838846 [0046] Alternatively, the olivine-type lithium-transition metal-phosphate (LMP) material as used herein may have a compound having a formula of Li1+x1(Fe1-y-zMnyAz)x2PO4.In the formula, x1 may range from about 0.0 to about 0.1. Specificaly, x1 may range from about 0.0 to about 0.09, about 0.0 to about 0.08, about 0.0 to about 0.07, about 0.0 to about 0.06, 0.01 to about 0.08, about 0.01 to about 0.06, about 0.02 to about 0.08, about 0.02 to about 0.06, about 0.02 to about 0.06, or about 0.01 to about 0.06. In the formula, x2 may range from about 0.6 to about 1.5. Specificaly, x2 may range from about 0.6 to about 1.4, about 0.8 to about 1.4, about 0.9 to about 1.3, about 0.9 to about 1.5, about 0.8 to about 1.2, about 0.9 to about 1.2, about 0.9 to about 1.1, or about 0.9 to about 1.0, about 0.8 to about 1.0, about 0.8 to about 0.9, about 0.9 to about 0.98, about 0.95 to about 1.0, about 0.91 to about 1.0, about 0.92 to about 1.0, about 0.94 to about 1.0, or about 0.96 to about 1.0. [0047] Further, in the formula Li1+x1(Fe1-y-zMnyAz)x2PO4,y may range from about 0.0 to about 1.0. Specificaly, y may range from about 0.1 to about 0.9, about 0.1 to about 0.8, about 0.1 to about 0.7, about 0.1 to about 0.6, about 0.1 to about 1.5, about 0.2 to about 0.8, about 0.3 to about 0.8, about 0.4 to about 0.8, about 0.5 to about 0.9, about 0.6 to about 1.0, about 0.6 to about 0.8, about 0.5 to about 0.8 or about 0.6 to about 0.7. Further, in the formula,z may range from about 0.00 to about 0.1. Specificaly, z may range from about 0.0 to about 0.09, about 0.0 to about 0.08, about 0.0 to about 0.07, about 0.02 to about 0.09, about 0.02 to about 0.08, 0.03 to about 0.08, 0.03 to about 0.06, 0.04 to about 0.07, 0.03 to about 0.07, 0.05 to about 0.07 or 0.05 to about 0.06. [0048] In addition, in the formula Li1+x1(Fe1-y-zMnyAz)x2PO4, A may be one or more of the alkali metals and/or one or more of the transition metals. The alkali metal may include Na, K, Rb, Cs and Fr or a combination thereof. The transition metal may include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Cd or a combination thereof. In an embodiment, A is one or more of: Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, or Na. [0049] In a particular embodiment, the LMP compound has a formula of, Li1+x1(Fe1-y-zMnyAz)x2PO4, whereinx1 is about 0.01 to about 0.06, x2 is about 0.9 to about 1, y is about 0.6 to about 0.7, z is about 0.0 to about 0.05, and A is one or more of: Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, or Na. In another embodiment, the LMP compound has a formula of, Li1+x1(Fe1-y-zMnyAz)x2PO4, whereinx1 is about 0.0 to about 0.1, x2 is about 0.9 to about 1.0, y is about 0.5 to about 0.8, z is about 0.0 to about 0.1, and A is one or more of: Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, or Na. [0050] Alternatively, the LMP compound may have a compound having a formula, LixMyPO4. In the formula, x may range from about 0.0 to about 1.5. In particular, x may range from about 0.1 to about 1.5, about 0.2 to about 1.0, about 0.5 to about 1.2, about 0.6 to about 1.2, about 0.6 to about 1.5, about 0.7 to about 1.3, about 0.8 to about 1.3, about 0.8 to about 1.2, about 0.8 to about 1.1, or about 0.9 to about 1.1. Further, in formula, LixMyPO4, the variable y may may range from about 0.0 to about 1.5. Specificaly, y 7 102268356.1 Docket No.113544-838846 may range from about 0.1 to about 1.5, about 0.2 to about 1.0, about 0.5 to about 1.5, about 0.6 to about 1.2, about 0.6 to about 1.5, about 0.7 to about 1.3, about 0.8 to about 1.3, about 0.8 to about 1.2, about 0.8 to about 1.1, about 0.8 to about 1.0 or about 0.9 to about 1.0. In addition, in the formula, LixMyPO4, M may be one or more of the transition metals or alkaline-earth metals or a combination thereof, including Be, Mg, Ca, Sr, Ba, Ra, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, or Cd. Further, A may be one or more of Ti or Mg. [0051] In an embodiment, the LMP compound has a formula of, LixMyPO4; whereinx is about 0.9 to about 1.1, y is about 0.9 to about 1.0, and M is one or more of: Fe, Ti or Mg. [0052] Alternatively, the LMP compound may have a compound having a formula, LixFeyAzPO4. In the formula, x may range from about 0.5 to about 1.5. Specificaly, x may range from about 0.6 to about 1.2, about 0.8 to about 1.3, about 0.9 to about 1.1, about 0.90 to about 1.1, about 0.95 to about 1.09, about 0.96 to about 1.05, about 0.98 to about 1.05, about 0.98 to about 1.09, about 0.98 to about 1.04, about 0.98 to about 1.02, about 0.99 to about 1.05, about 0.97 to about 1.04, about 0.98 to about 1.04, about 0.99 to about 1.03, or about 0.99 to about 1.02. Further in the formula, y may range from about 0.6 to about 1.5. More specificaly, y may range from about 0.6 to about 1.4, about 0.8 to about 1.4, about 0.9 to about 1.3, about 0.9 to about 1.5, about 0.8 to about 1.2, about 0.9 to about 1.2, about 0.9 to about 1.1, about 0.9 to about 1.0, about 0.8 to about 1.0, about 0.8 to about 0.9, about 0.9 to about 0.98, about 0.95 to about 1.0, about 0.91 to about 1.0, about 0.92 to about 1.0, about 0.94 to about 1.0, about 0.96 to about 1.0. In addition, in the formula, z may range from about 0.00 to about 0.1. More specificaly, z may range from about 0.01 to about 0.09, about 0.02 to about 0.08, about 0.03 to about 0.07, about 0.0 to about 0.09, about 0.02 to about 0.09, about 0.02 to about 0.07, about 0.02 to about 0.06, about 0.02 to about 0.05. [0053] In addition, in the formula LixFeyAzPO4,A may be one or more of the alkaline-earth metals or a combination thereof, including Be, Mg, Ca, Sr, Ba, or Ra. Alternatively, A may be one or more of the transition metals or a combination thereof, including Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Rh, Pd, or Cd. Further, A may be one or more of Ti or Mg. [0054] In an embodiment, the LMP material comprises LixFeyAzPO4 whereinx is 0.99-1.02, y is 0.96-1.0, z is 0.00-0.03, and A is one or more of Ti or Mg. [0055] The LMP material may further include one or more type of oxidation impurities. For example, the oxidization impurities may include any foreign substances within the LMP material that have undergone oxidation. Alternatively, the oxidization impurities include trace elements including transition metals, or transition metal ions. In an embodiment, the oxidized impurities include Al, Cu, Fe, Mn, Co, Ni or Mg. 8 102268356.1 Docket No.113544-838846 [0056] Alternatively, in some embodiments the LMP material does not include oxidization impurities. As described herein, the olivine-type material may be substantialy pure, free of oxidization impurities, but has poor electrochemical performance due to poor electrical conductivity. [0057] Further, the oxidization impurities when present in the olivine-type LMP material may be present in an amount of greater than 10% by weight, greater than 8% by weight or greater than 5% by weight. [0058] In accordance with methods described herein, the LMP material may include an amount of inorganic carbon. The inorganic carbon may be present in an amount of less than 5% by weight. Specificaly, the inorganic carbon may be present in an amount of less than 3% by weight, less than 2% by weight, less than 1% by weight, or less than 0.5% by weight. In an aspect, the LMP material comprises no inorganic carbon or the amount of inorganic carbon present is undetectable. [0059] Alternatively, the inorganic carbon may be present in an amount of less than 0.3% by weight, less than 0.2% by weight, or less than 0.1% by weight. In an embodiment, the LMP material includes less than 0.77% inorganic carbon by weight or less than 0.28% inorganic carbon by weight. [0060] Further, as described herein the average oxidation state of at least two transition metal species in the LMP material differs from each other. The average oxidation state of the transition metal present in the LMP material may be between 2+ to 3+. In an embodiment, the average oxidation state of the transition metal present in the LMP material is 2+. [0061] Fruther according to the methods described herein, one or more carbon-containing compounds are added to a dry miled LMP powder to form a mixture. The one or more carbon-containing compounds are introduced to reduce the olivine-type material. In addition, the one or more carbon-containing compounds is at least partialy decomposed or completely decomposed. [0062] According to an embodiment of the invention, the one or more carbon-containing compounds form a carbon coating on the LMP material. The carbon coating modifies the surface chemical stability, enhances the structural stability. It further improves diffusion of Li-ions and reduces the oxidation impurities in the LMP material. [0063] The one or more carbon-containing compound is obtained from a carbon source. The carbon source as described herein may be an organic polymer, a saccharide compound, an aromatic hydrocarbon compound, or a gas containing carbon atoms. For example, the carbon-containing compound is selected from an aromatic hydrocarbon compound may include an alcohol, an acid, or a ketone. The aromatic hydrocarbon compound may include toluene, p-xylene, asphalt, or paraffin oil and, the gas containing carbon atoms may include ethylene, methane, acetylene, carbon monoxide or the like. 9 102268356.1 Docket No.113544-838846 [0064] Alternatively, the carbon-containing compound may be ascorbic acid, malic acid, tartaric acid, succinic acid, fumaric acid, citric acid, oxalic acid, gluconic acid, or lauric acid. The carbon-containing compound may also include carbon nanotubes, graphene, or carbon black. In some embodiments, the carbon-containing compound includes sugars. For example, sucrose, glucose, dextrose, fructose, lactose, or maltodextrin. [0065] Another source of the carbon-containing compound may include organic polymers comprising polyethylene, polypropylene, polystyrene, polyethylene glycol, polyvinylpyrrolidone, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylonitrile, polymethyl methacrylate, polyurethane, polyacrylamide, poly(acrylic acid), polyethylene oxide, poly(ethylene imine), carboxylmethyl celulose, hydroxypropyl celulose, polyethylene oxide, alkylated polyethylene oxide, cross-linked polyethylene oxide, polyvinyl ether, poly(methyl methacrylate), polyvinylidene fluoride, a copolymer of polyhexafluoropropylene and polyvinylidene fluoride, poly(ethyl acrylate), polytetrafluoro ethylene, polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, derivatives, blends, or copolymers thereof. [0066] In a preferred embodiment, the carbon-containing compound is polyvinylpyrrolidone (PVP, (C6H9NO)n). PVP is used to obtain improved stability and rate capability. During the synthesis steps, the decomposition of PVP can cause carbon material to form on the electrode surface, resulting in an improved electrical conductivity of the active material. In addition, a reducing atmosphere, is generated by the decomposition of PVP, which potentialy induces an oxygen loss. In an embodiment, PVP reduces surface area and changes morphology of the cathode material. [0067] In an embodiment, the carbon-containing compound is selected from the group consisting of organic carbon sources, including sucrose, glucose, lactose, maltodextrin, soluble starch, polymers (e.g. poly(ethylene glycol), poly(vinyl alcohol), poly(acrylic acid), polyvinyl pyrrolidone), vinyl alcohol, acrylic acid, citric acid, oxalic acid, and lauric acid; inorganic carbons; urea; and combinations thereof. [0068] In an embodiment, the carbon-containing compound may be added an amount equal to about 0.0 to about 3 wt%, based on the total weight of the olivine-type LMP material. In an embodiment, the carbon- containing compound may be added in an amount of 0.0 wt% to 1.5 wt%, 0.01 wt% to 1.5 wt%, 0.06 wt% to 1.2 wt%, 0.1 wt% to 0.5 wt%, 0.15 wt% to 0.3 wt%, 0.2 wt% to 0.3 wt%. Alternatively, the carbon- containing compound may be added in an amount of 0.3 wt% to 1.0 wt%, 0.5 wt% to 0.8 wt%, 0.6 wt% to 0.8 wt%, or 0.7 wt% to 0.8 wt%. [0069] The carbon source may include three carbon-containing compounds present in a ratio of 1:1:1, 1:1:2, 1:2:1, 2:1:1, 2:2:1, 1:2:2, 2:1:2, 1:1:3, 1:3:1, 3:1:1, 3:3:1, 1:3:3, 3:1:3; 1:1:4, 1:4:1, 4:1:1, 4:4:1, 4:1:1, 1:4:4, or 4:1:4. Optionaly, the three carbon-containing compounds may be present in a ratio of 1:2:3, 1:3:2, 3:2:1, 2:3:1, 3:1:2, 1:4:3, 3:4:1, 3:1:4, 1:3:4, or 4:3:1. Alternatively, carbon source includes four carbon- 10 102268356.1 Docket No.113544-838846 containing compounds present in a ratio of 1:1:1:1, 1:2:2:1, 1:1:1:1, 1:2:2:1, 1:1:1, 1:3:1, 1:1:1:1, or 1:2:2:1. In another embodiment, the carbon source may include two carbon-containing compounds present in a ratio of 1:1, 1:2, or 2:1. [0070] Further, according to the methods described herein the particles of the olivine-type LMP material undergo dry miling to obtain the dry miled LMP powder. Dry miling treatment causes intensive mixing and, at the same time, deagglomeration or a reduction in the size of the particles. The particle size of the dry miled LMP powder can be expressed as a d50 value, as known in the art. It further results in the reduction of the d50 value of the LMP powder, wherein the dry miled LMP powder has a d50 of less than or equal to 30 µm, less than or equal to 25 µm, less than or equal to 20 µm. In another embodiment, the dry miled LMP powder has a d50 of ≤15 µm, ≤13 µm, ≤12 µm, ≤11 µm or ≤10 µm. [0071] In an embodiment the d50 value of the LMP powder may range from about 500 nm to about 30 µm. More specificaly, the d50 range may be from about 800 nm to about 25 µm, about 750 nm to about 25 µm about 1000 nm to about 20 µm, about 5 µm to about 20 µm, about 5 µm to about 15 µm, or about 5 µm to about 10 µm. [0072] In an embodiment, the dry miled LMP powder has a d50 of about 1 µm to about 30 µm, about 5 µm to about 25 µm, about 5 µm to about 20 µm, about 5 µm to about 15 µm or about 5 µm to about 10 µm. Alternatively, the dry miled LMP powder may have a d50 of about 400 nm to about 800 nm, 450 nm to about 750 nm, about 400 nm to about 750 nm, about 400 nm to about 750 nm, about 400 nm to about 600 nm or about 400 to about 500 nm. [0073] Dry miling is wel-known in the art and any apparatus suitable to the person skiled in the art and, available in the art may be used to carry out the dispersing or miling treatment according to the invention. Miling or dry miling alows sufficient shearing forces or turbulence to be generated to achieve intensive mixing and, at the same time, deagglomeration or a reduction in the size of the particles, resulting in a D90 value of less than 50 μm. Preferred apparatuses comprise dispersing means (with or without pump rotors), Ultraturrax, mils such as coloid mils or Manton-Gaulin mils, intensive mixers, centrifugal pumps, in-line mixers, mixing nozzles, such as injector nozzles, or ultrasound appliances. Apparatuses of this type are known per se to the person skiled in the art. The setings required to obtain the desired effect on the mean particle size for the olivine-type LMP material can be determined using routine tests as known to a person skiled in the art. [0074] In many cases, as part of the miling treatment according to the invention, mechanical power optionaly in the form of crushing, grinding, and/or impacting is introduced into the olivine-type LMP material to reduce the particle size. This introduction of power can be determined in a known way for the particular apparatus, for example using the formula P=2πnM, where M represents the torque and n represents the rotational speed, when using an Ultraturrax stirrer. 11 102268356.1 Docket No.113544-838846 [0075] Further, according to the methods described herein the mixture of the LMP material and the carbon-containing compound is miled with a liquid medium to form a wet-miled slurry. The liquid medium used in the wet-miling process may be organic or inorganic solvents known in the art. Optionaly, non- aqueous solvents can also be utilized. For example, the liquid medium is an organic solvent selected from the group consisting of methanol, ethanol, isopropanol, 2-butanol, acetone, 2-butanone, and any combination thereof. In an embodiment, the liquid medium is water. [0076] The wet-miled slurry formed in accordance with the methods described herein includes the LMP material and the carbon-containing compound. The wet-miled slurry leads to the formation of an intimate admixture of solids. The admixture of solids has a homogeneous distribution. In some embodiments, the intimate admixture of the solids has a large number of smal crystal nuclei of approximately the same size. [0077] The method further includes drying the wet-miled slurry to remove the liquid medium. The wet- miled slurry is dried to yield a dried mixture of primary particles including the olivine-type LMP material and the carbon-containing compound. [0078] The liquid medium is removed by evaporation to recover the solids and/or the primary particles. Alternatively, the liquid is removed from the wet-miled slurry using any method known to one skiled in the art. Non-limiting examples of the drying method include spray drying, air drying, or vacuum drying. [0079] In an embodiment, the liquid medium is removed by spray drying. The process of spray drying can minimize the separation of phases during drying. It provides favorable morphologies of the dried solids that enhance their handling characteristics (e.g., “flowability”). It further involves atomizing a liquid slurry containing active materials, binders, and additives into fine droplets, which are rapidly dried to form spherical particles. The resulting powder exhibits controled particle size distribution and excelent morphology, making it ideal for electrode fabrication. The spray drying process alows precise control over particle size, achieves homogenous mixing, maximizes surface area, and uniformly distributes the individual particles. [0080] The desired spray drying inlet and outlet temperature may be varied. The desired spray drying inlet temperature ranges between about 50 °Cto about 500 °C. More specificaly, about 50 °Cto about 300 °C, about 50 °Cto about 250 °C, about 50 °Cto about 200 °C or about 100 °Cto about 250 °C. Alternatively, the desired spray drying inlet temperature may range between about 100 °Cto about 500 °C, about 100 °Cto about 400 °C, or about 100 °Cto about 300 °C. Further, the desired spray drying inlet temperature may range about 50 °Cto about 180 °C, about 100 °Cto about 180 °C, or about 150 °Cto about 180 °C. [0081] Alternatively, the desired spray drying inlet temperature is about 140 °C. In another embodiment, the desired spray drying inlet temperature is about 150 °C. In another embodiment, the desired spray drying inlet temperature is about 160 °C. 12 102268356.1 Docket No.113544-838846 [0082] The desired spray drying outlet temperature may range about 50 °Cto about 500 °C. More specificaly, about 50 °Cto about 300 °C, about 50 °Cto about 250 °C, about 50 °Cto about 200 °C or about 80 °Cto about 250 °C. Alternatively, the desired spray drying outlet temperature may range about 80 °Cto about 150 °C, about 90 °Cto about 125 °C, or about 95 °Cto about 150 °C. Further, the desired spray drying outlet temperature may range about 80 °Cto about 120 °C, about 90 °Cto about 110 °C, or about 100 °Cto about 110 °C. [0083] In an embodiment, the desired spray drying outlet temperature may be about 90 °C, about 95 °C, about 100 °C or about 105 °C. [0084] According to the methods described herein, spray drying yields primary particles including particles of the olivine-type LMP material and the carbon-containing compound. The particle size of the primary particles may be expressed as a d50 value, as known in the art. In an embodiment, the average d50 value of the primary particles after spray drying is about 50 nm to about 5000 nm. [0085] The primary particles may have a d50 ranging from about 50 nm to about 4000 nm. More specificaly, about 50 nm to about 3000 nm, about 100 nm to about 3000 nm, about 200 nm to about 1000 nm, or about 500 nm to about 1000 nm. Alternatively, the primary particles may have a d50 ranging from about 200 nm- about 5000 nm, about 300 nm- about 3000 nm, about 400 nm- about 3000 nm, about 500 nm to about 5000 nm, about 500 nm to about 2500 nm, about 500 nm to about 1500 nm, about 700 nm to about 2500 nm, about 800 nm to about 2500 nm, about 900 nm to about 3000 nm, about 1000 nm to about 3000 nm, about 1000 nm to about 2000 nm, about 1500 nm to about 3000 nm, about 1500 nm to about 2000 nm, or about 1500 nm to about 2500 nm. [0086] Further, the primary particles obtained via spray drying are calcinated to yield carbon-coated secondary particles. In other words, the primary particles are subsequently heated in a furnace to a desired temperature under a controled atmosphere. [0087] During the calcination process, the primary particles are present in a powdered form and are typicaly held in a graphite crucible during the heating process. Alternatively, as known in the art, alumina crucibles can also be used. The powder depth can range from 0.2 cm to 15 cm with the crucible. [0088] Calcination is a method known to one skiled in the art. Calcination involves exposing the dried mixture to temperatures of about 700 °C to about 900 °C to remove any remaining water or binder from the drying process, and to fuse the metals tightly together. Precise temperature control throughout the process is critical, as it influences the electrochemical performance, optimizes the crystal structure, and particle size of the materials. 13 102268356.1 Docket No.113544-838846 [0089] As known to a person skiled in the art, calcination involves a flow of inert gas, usualy nitrogen or argon, is used to remove traces of oxygen as wel as gaseous byproducts. In some embodiments, the atmosphere can be made mildly reductive by inclusion of traces of reducing gases such as hydrogen, methane, or ammonia in the incoming gas flow. In some embodiments, the furnace interior containing the primary particles can be evacuated and placed under vacuum to remove ambient gases before refiling with inert, oxygen-free gases. [0090] During the calcination process an internal temperature of the furnace is raised from room temperature at 0.5-15 °C/min continuously or with one or more intermediate hold temperature periods. In an embodiment, the furnace is heated in a nitrogen-purged furnace at 8°C/min. [0091] In an embodiment, a final hold temperature ranges from about 500 °C to about 1000 °C. In an embodiment, a final hold temperature is about 600 to about 800 °C. In other embodiments, the final hold temperature ranges from about 650 °C to about 850 °C. In another embodiment, a final hold temperature ranges from about 650 °C to about 750 °C. In an embodiment, a final hold temperature ranges from about 680 to about 720 °C. In an embodiment, a final hold temperature is about 700 °C. [0092] The desired calcination furnace temperature ranges from about 100 °Cto about 10000 °C. More specificaly, the furnace temperature ranges from about 200 °Cto about 8000 °C, about 300 °Cto about 5000 °C, about 300 °Cto about 2000 °C or about 500 °Cto about 1000 °C. Alternatively, the desired calcination furnace temperature More specificaly, the furnace temperature ranges from about 100 °Cto about 2000 °C, about 500 °Cto about 1500 °C, or about 600 °Cto about 1000 °C, about 500 °Cto about 1000 °C, about 600 °Cto about 900 °C, or about 650 °Cto about 850 °C. In an embodiment, the desired calcination furnace temperature is about 650 °Cto about 850 °C. [0093] According to an aspect of the instant invention, the final temperature is held for about 0.5 to about 8 hours before cooling to a safe handling temperature, usualy below 100 °C. The final temperature may be held for about 1 to about 4 hours. In an embodiment, the final temperature is held for about 1 hour. [0094] Calcination produces secondary particles including the particles of the olivine-type LMP material and the carbon-containing compound. The secondary particles are stoichiometricaly balanced carbon coated particles of the LMP material. In a specific embodiment, the secondary particles are carbon-coated. [0095] The particle size of the carbon-coated secondary particles may be expressed as a d50 value, as known in the art. In an embodiment, the carbon-coated secondary particles may have a d50 ranging from about 50 nm to about 5000 nm in size. More specificaly, the secondary particles may have a d50 ranging from about 100 nm to about 5000 nm, about 100 nm to about 3000 nm, about 200 nm to about 3000 nm, about 200 nm to about 1000 nm, about 500 nm to about 1000 nm, about 200 nm to about 5000 nm, about 300 nm to about 3000 nm, about 400 nm to about 3000 nm, about 500 nm to about 5000 nm, about 500 nm 14 102268356.1 Docket No.113544-838846 to about 2500 nm, about 500 nm to about 1500 nm, about 700 nm to about 2500 nm, about 800 nm to about 2500 nm, about 900 nm to about 3000 nm, about 1000 nm to about 3000 nm, about 1000 nm to about 2000 nm, about 1500 nm to about 3000 nm, about 1500 nm to about 2000 nm, or about 1500 nm to about 2500 nm. [0096] Alternatively, the carbon-coated secondary particles may have a d50 ranging from about 50 nm to about 500 nm. More specificaly, the secondary particles may have a d50 ranging from 100 nm to about 500 nm, about 100 nm to about 300 nm, about 200 nm to about 300 nm, about 200 nm to about 250 nm, about 200 nm to about 500 nm, about 50 nm to about 150 nm, about 70 nm to about 250 nm, about 80 nm to about 250 nm, about 90 nm to about 300 nm, about 100 nm to about 300 nm, about 100 nm to about 200 nm, about 150 nm to about 300 nm, about 150 nm to about 200 nm, or about 150 nm to about 250 nm or 100 nm to about 300 nm. [0097] Further, the carbon-coated secondary particles may have a d50 ranging from about 10 nm to about 500 nm. More specificaly, the secondary particles may have a d50 ranging from about 50 nm to about 500 nm, about 50 nm to about 500 nm, about 80 nm to about 500 nm, about 80 nm to about 450 nm, about 100 nm to about 500 nm, about 100 nm to about 450 nm, about 100 nm to about 400 nm, about 120 nm to about 500 nm, about 120 nm to about 450 nm or about 150 nm to about 400 nm. [0098] Optionaly, the carbon-coated secondary particles may have a d50 ranging from about 10 nm to about 1000 nm. More specificaly, the secondary particles may have a d50 ranging from about 50 nm to about 250 nm, about 80 nm to about 300 nm, about 100 nm to about 300 nm, about 120 nm to about 300 nm, about 150 nm to about 300 nm, about 180 nm to about 450 nm, about 180 nm to about 400 nm, about 200 nm to about 450 nm, about 200 nm to about 300 nm or about 100 nm to about 400 nm. [0099] The carbon-coated secondary particles may have a d50 of about 50 nm, about 80 nm, about 100 nm, about 120 nm, about 150 nm, about 180 nm, about 200 nm, about 250 nm, about 300 nm, or about 350 nm. In some embodiments, the secondary particle diameter ranges from about 30 nm, about 90 nm, about 110 nm, about 120 nm, about 140 nm, about 160 nm, about 190 nm, about 220 nm, about 280 nm, about 310 nm, about 340 nm, about 380 nm or about 410 nm. In another embodiment, the secondary particles have a d50 of about 4500 nm, about 4000 nm, about 3000 nm, about 2000 nm, about 1500 nm, about 1800 nm, about 1500 nm, about 1000 nm, about 900 nm, or about 750 nm. The secondary particles may have a d50 of about 2800 nm, about 2500 nm, about 2800 nm, about 3100 nm, about 3400 nm, about 3800 nm or about 4100 nm. [0100] In an embodiment, the carbon-coated secondary particles have a d50 ranging from about 50 nm to about 500 nm. In another embodiment, the secondary particles have a d50 ranging from about 100 nm to about 300 nm. [0101] In an aspect of the invention, the LMP in the secondary particles has a decreased oxidation impurity content. The oxidation impurity present in the secondary particle content may be quantified 15 102268356.1 Docket No.113544-838846 according to any method(s) known to a person skiled in the art, including but not limited to X-ray powder diffraction. As analyzed with the methods provided herein, the oxidation impurity in the secondary particles may be present in an amount of less than 5% by weight. More preferably, the oxidation impurity content may be less than 4% by weight, less than 3% by weight, less than 2% by weight or less than 1% by weight. [0102] Further, the LMP in the secondary particles may have an oxidation impurity content of less than or equal to 1% by weight. In an embodiment, the LMP in the secondary particles has an oxidation impurity content of less than or equal to 0.1% by weight. [0103] Alternatively, the oxidation impurity content may be less than 0.5% by weight, less than 0.1% by weight, less than 0.08% by weight, less than 0.05% by weight, less than 0.03% by weight or less than 0.01% by weight. In an embodiment, the oxidation impurity content in the secondary particles is negligible. [0104] The desired calcination temperature induces at least a partial decomposition of the carbon- containing compounds. Further, the carbon-containing compounds deposit predominantly as a carbon layer on the surface of the olivine-type material particles. In addition, the formation of the carbon layer alows fusion products to be used as performant cathode materials for lithium-ion bateries. [0105] The desired calcination temperature does not re-fuse the olivine-type material. According to embodiments described herein, during calcination, the carbon-containing compounds reduce the oxidized olivine-type material and simultaneously break down to form a desirable carbon layer. The subsequent heating step alows the use of oxidized, defective olivine materials. In some embodiments calcining the dried mixture imparts pyrophosphate impurities in the secondary particles. [0106] The methods described herein alow the use of bare olivine materials, synthesized by an initial solid-state reaction. The olivine materials used herein may be synthesized by other known methods in the art. In a series of steps, the bare olivine materials are carbon-coated in a to yield performant cathodes. The carbon coated olivine materials have sufficient electrical conductivity to enhance the performance of the olivine materials in lithium-ion batery cathodes. [0107] In an additional aspect of the invention, the method further includes formulating a cathode sheet using the secondary particles. The carbon coated secondary particles used herein have a d50 ranging from about 100 nm to about 1000 nm, about 100 nm to about 800 nm, 150 nm to about 600 nm, 150 nm to about 450 nm, about 150 nm to about 300 nm. In another embodiment, the secondary particles have a d50 ranging from about 150 nm to about 200 nm. [0108] The method of formulating the cathode further includes adding one or more additional compounds comprising at least one element, wherein the one or more additional compounds is added in an amount that does not alter the stoichiometry of the secondary particles . As understood herein, an amount of the at least 16 102268356.1 Docket No.113544-838846 one element also does not alter the overal stoichiometry of the secondary particles . Further, the at least one of the elements may be selected from the group consisting of magnesium, scandium, titanium, vanadium, chromium, cobalt, nickel, zinc, molybdenum, niobium, tungsten, aluminum, silicon, tin, and any combination thereof. [0109] In an embodiment, the one or more additional compounds may added in an amount equal to 0.00 wt% to 0.01 wt%, 0.01 wt% to 0.02 wt%, 0.02 wt% to 0.03 wt%, 0.02 wt% to 0.04 wt%, 0.03 wt% to 0.04 wt%, 0.04 wt% to 0.2 wt%, 0.05 wt% to 0.2 wt%, 0.05 wt% to 0.1 wt%, 0.08 wt% to 0.15 wt%, or 0.1 wt% to 0.2 wt%. [0110] Another aspect of the invention includes a method for decreasing oxidation impurities in an olivine-type lithium-transition metal-phosphate (LMP) material. The method includes the folowing steps. Firstly, dry miling particles of the olivine-type LMP material to obtain a dry miled LMP powder. The olivine-type LMP material includes oxidation impurities in an amount of greater than 5% by weight. Further, obtaining a dry miled powder. Next, adding a carbon-containing compound to form a mixture with the LMP. The carbon-containing compound is selected from the group consisting of glucose, sucrose, lactose, maltodextrin, soluble starch, polyethylene glycol, vinyl alcohol, acrylic acid, citric acid, oxalic acid, lauric acid, urea, and combinations thereof. The method further includes, miling the LMP and carbon- containing compound mixture with a liquid medium to form a wet-miled slurry. Additionaly, drying the wet-miled slurry to yield primary particles comprising particles of the olivine-type LMP material and the carbon-containing compound. The primary particles have a d50 ranging from about 50 nm to about 5000 nm. Finaly, calcining the primary particles to produce carbon-coated secondary particles having a d50 ranging from about 50 nm to about 5000 nm. The LMP in the secondary particles has a decreased oxidation impurity content of less than 1% by weight. [0111] As described herein, the olivine-type lithium-transition metal-phosphate (LMP) material comprises lithium iron phosphate (LFP) and lithium manganese iron phosphate (LMFP). [0112] Also provided herein are compositions comprising carbon-coated LMP materials for lithium-ion bateries made from the methods described herein. [0113] In one aspect, the composition includes a useful cathode material comprising carbon-coated olivine-type LMP materials comprising less than 25 wt% of oxidized impurities. Further, the oxidized impurities may be present in an amount less than 15 wt%, less than 10 wt%, less than 5 wt%, less than 3 wt%, less than 2.5 wt%, less than 1.5 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt%. In an embodiment, the oxidized impurities are present in a negligible amount. [0114] While the embodiments provided herein describe materials synthesized using solid-state and fusion synthesis, one of ordinary skil in the art would recognize that the present technology is applicable to materials synthesized through various other synthesis routes including, but not limited to, melting, fusion, 17 102268356.1 Docket No.113544-838846 solid-state, hydrothermal, etc. Similarly, one of ordinary skil in the art would recognize that the present technology is applicable to off-stoichiometric material according to its chemical composition in addition to (or in place of) the crystalographic phase of the material. For example, one of ordinary skil in the art would recognize that the material can be an amorphous material, and the chemical stoichiometry of the amorphous material can be adjusted using the present technology. [0115] EXAMPLES [0116] It wil be appreciated that the folowing examples are intended to ilustrate but not to limit the present disclosure. Various other examples and modifications of the foregoing description and examples wil be apparent to a person skiled in the art after reading the disclosure without departing from the spirit and scope of the disclosure, and it is intended that al such examples or modifications be included within the scope of the appended claims. [0117] Olivine-type LMP materials useful as cathode materials in lithium-ion bateries can be synthesized by via both solid-state and liquid-phase reactions. Briefly, in solid-state reactions, an intimate admixture of solid components created by miling and spray drying is calcined in inert atmosphere, typicaly at temperatures ranging from 650 ºC to 850 ºC, to create the fused olivine product. In a liquid-phase reaction, in which an intimate mixture of precursors is raised to a temperature above the melting point of the final product, the reaction of the precursors creates the liquid phase of the olivine product, which as a liquid medium accelerates further reaction and homogenization. The liquid phase is then cooled to provide the olivine material in solid form. Cooling can be achieved by methods such as casting the melt into an ingot or spraying the liquid into a container, and may take place under oxidizing, reducing, or inert atmosphere. To be useful as cathode materials in lithium-ion bateries, olivine-type materials must both be (a) reduced in size to approximately micron-scale or smaler particles and (b) coated at the level of individual particles with an electricaly conductive layer. [0118] Summary of non-limiting examples synthesized herein is provided in Table 1. [0119] Table 1: Example Chemistry Precursor Main Precursor Stoichiometric Has Dopant(s) number synthesis oxidized carbon corection electrochemistry route impurity wt. % data (%) 1 LMFP Solid- LISICON 0.28% No yes Ti state (5%) 18 102268356.1 Docket No.113544-838846 2 LMFP Solid- LISICON 0.77% No No Ti state (6%) 3 LMFP Solid- LISICON 0% No No Ti state (34%) 4 LMFP Solid- FePO4 0.18% No No Ti state (15%) 5 LMFP Fusion LISICON 0% No Yes Ti (9%) 6 LMFP Fusion LISICON 0% Yes (Li, Fe, Yes Ti, Mg (18%) Mn) 7 LFP Fusion LISICON 0% No yes None (18%) [0120] Example 1: [0121] Material: A solid-state-synthesized sample of LMFP was generated for use whose compositional analysis by powder X-ray diffraction (PXRD) indicated the crystaline fraction contained 8% oxidized impurities by weight (90.7% LMFP, 5.3% Li3Fe2(PO4)3, 2.4% Li3PO4, and 1.6 % metal pyrophosphates). It has 0.28% carbon by weight, as measured by C/S combustion elemental analysis. Because of its substantial oxidized impurities and low carbon content, the LMFP sample synthesized herein is not a useful cathode material. Therefore, we have applied the invention disclosed herein to remedy the material. [0122] The synthesized LMFP powder (24g) was combined with glucose (0.96 g), polyethylene glycol (0.96 g), polyvinylpyrrolidone (0.24 g), titanium dioxide (0.072 g), lithium carbonate (0.04 g), and water (56 g). The resulting slurry was miled in a planetary bal mil for 40 minutes with 0.5 mm beads. The slurry was dried in a Yamato spray dryer. A 12 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 765°C for 2 h, then cooled, to provide 10 g of a fine black powder. The XRD diffractogram of the product shows phase-pure LMFP, containing no residual oxidized impurities and less than 1.2% trace impurities. A residual carbon layer remained after heat treatment: the final powder contained 1.75% carbon by weight, as measured by C/S combustion elemental analysis. Further, the powder’s electrical conductivity, measured on a powder pelet compacted at 20 MPa by a four-point probe, was 60 ohm*cm. The powder was formed into a cathode sheet by formulation into a 95:2.5:2.5 slurry with conductive carbon additive and poly(vinylidene fluoride) binder combined in NMP which was coated and dried onto an aluminum foil backing. Circular punches of this sheet were assembled into coin cels with Celgard separators, lithium metal anodes, and 1.2M LiPF6 in 19 102268356.1 Docket No.113544-838846 EC:EMC (3:7 w/w) plus 2wt% vinylene carbonate electrolyte. The coin cels had a specific discharge capacity of 149 mAh/g at C/5 and 136 mAh/g at 1C when cycled from 2.5-4.4V. The powder metrology and electrochemical data demonstrate that (1) the carbon coating is wel-distributed over the LMFP particles, (2) it is sufficiently electricaly conductive to yield good electrochemistry, and (3) it does not deleteriously affect the processability of the cathode into an electrode. See Fig.1 and Fig.2. [0123] Example 2: [0124] Material: A solid-state-synthesized sample of LMFP was generated for use whose compositional analysis by PXRD indicated the crystaline fraction contained 18% oxidized impurities by weight (81.8% LMFP, 6.3% Li3Fe2(PO4)3, 7% Li3PO4, and 4.9 % metal pyrophosphates). It has 0.77% carbon by weight, as measured by C/S combustion elemental analysis. Because of its substantial oxidized impurities and low carbon content, the LMFP sample synthesized herein is not a useful cathode material. Therefore, we have applied the invention disclosed herein to remedy the material. [0125] The synthesized LMFP powder (24g) was combined with glucose (0.96 g), polyethylene glycol (0.96 g), polyvinylpyrrolidone (0.24 g), titanium dioxide (0.072 g), and lithium carbonate (0.04 g). The resulting slurry was miled in a planetary bal mil for 40 minutes with 0.5 mm beads. The slurry was dried in a Yamato spray dryer. A 12 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 700°C for 2 h, then cooled, to provide 10 g of a fine black powder. The XRD diffractogram of the product shows phase-pure LMFP, containing no residual oxidized impurities and less than 1.1% trace impurities. A residual carbon layer remained after heat treatment: the final powder contained 2.07% carbon by weight, as measured by C/S combustion elemental analysis. Further, the powder’s electrical conductivity, measured on a powder pelet compacted at 20 MPa by a four-point probe, was 169 ohm*cm. Akin to the previous example, the powder metrology and data demonstrate that (1) the carbon coating is wel-distributed over the LMFP particles, (2) it is sufficiently electricaly conductive to yield good electrochemistry. Thus, the invention disclosed herein can, starting with previously unusable material, generate cathode material useful in lithium-ion bateries. See Fig.3. [0126] Example 3: [0127] Starting Material: A solid-state-synthesized sample of LMFP was generated for use whose compositional analysis by PXRD indicated the crystaline fraction contained 37% oxidized impurities by weight (62.7% LMFP, 34.3% Li3Fe2(PO4)3, 2.5% Li3PO4, and 0.5% metal pyrophosphates). It has 0% carbon by weight. Because of its substantial oxidized impurities and lack of carbon, the LMFP sample synthesized herein is not a useful cathode material. Therefore, we have applied the invention disclosed herein to remedy the material. 20 102268356.1 Docket No.113544-838846 [0128] The LMFP powder (24g) was combined with glucose (0.96 g), polyethylene glycol (0.96 g), polyvinylpyrrolidone (0.24 g), titanium dioxide (0.072 g), and lithium carbonate (0.04 g). The resulting slurry was miled in a planetary bal mil for 40 minutes with 0.5 mm beads. The slurry was dried in a Yamato spray dryer. A 12 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 765°C for 2 h, then cooled, to provide 10 g of a fine black powder. The XRD diffractogram of the product shows phase-pure LMFP, containing no residual oxidized impurities and less than 1.1% trace impurities. A residual carbon layer remained after heat treatment: the final powder contained 1.91% carbon by weight, as measured by C/S combustion elemental analysis. Further, the powder’s electrical conductivity, measured on a powder pelet compacted at 20 MPa by a four-point probe, was 35 ohm*cm. Akin to the previous example, the powder metrology and data demonstrate that (1) the carbon coating is wel-distributed over the LMFP particles, (2) it is sufficiently electricaly conductive to yield good electrochemistry. Thus, the invention disclosed herein can, starting with previously unusable material, generate cathode material useful in lithium-ion bateries. See Fig.4. [0129] Example 4: [0130] Starting Material: A solid-state-synthesized sample of LMFP was generated for use whose compositional analysis by PXRD indicated the crystaline fraction contained 25% oxidized impurities by weight (75% LMFP, 14.6% FePO4, 6.5% Li3PO4, 2.2% Li3Fe2(PO4)3, and balance metal pyrophosphate). It has 0.77% carbon by weight, as measured by C/S combustion elemental analysis. Because of its substantial oxidized impurities and low carbon content, the LMFP sample synthesized herein is not a useful cathode material. Therefore, we have applied the invention disclosed herein to remedy the material. [0131] The powder (24g) was combined with glucose (0.96 g), polyethylene glycol (0.96 g), polyvinylpyrrolidone (0.24 g), titanium dioxide (0.072 g), and lithium carbonate (0.04 g). The resulting slurry was miled in a planetary bal mil for 40 minutes with 0.5 mm beads. The slurry was dried in a Yamato spray dryer. A 12 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 765°C for 2 h, then cooled, to provide 10 g of a fine black powder. The XRD diffractogram of the product shows phase-pure LMFP, containing no residual oxidized impurities and less than 1.1% trace impurities. A residual carbon layer remained after heat treatment: the final powder contained 1.59% carbon by weight, as measured by C/S combustion elemental analysis. Further, the powder’s electrical conductivity, measured on a powder pelet compacted at 20 MPa by a four-point probe, was 23 ohm*cm. Akin to the previous example, the powder metrology and data demonstrate that (1) the carbon coating is wel-distributed over the LMFP particles, (2) it is sufficiently electricaly conductive to yield good electrochemistry. Thus, the invention disclosed herein can, starting with previously unusable material, generate cathode material useful in lithium-ion bateries. See Fig.5. [0132] Example 5: 21 102268356.1 Docket No.113544-838846 [0133] Starting Material: A fusion-synthesized sample of LMFP was generated for use whose compositional analysis by PXRD indicated the crystaline fraction contained 17% oxidized impurities by weight (83.1% LMFP, 8.9% Li3Fe2(PO4)3, 0.9 % Li3PO4, and 7.1% metal pyrophosphates). It has no carbon content. Because of its substantial oxidized impurities and lack of carbon, the LMFP sample synthesized herein is not a useful cathode material. Therefore, we have applied the invention disclosed herein to remedy the material. [0134] The solid was ground and jet miled until 99% of the mass had a particle size less than 11.2 um as measured by dry laser diffraction particle size analysis. This dry miled powder (24g) was combined with glucose (0.96 g), polyethylene glycol (0.96 g), polyvinylpyrrolidone (0.24 g), titanium dioxide (0.072 g), and water (56 g). The resulting slurry was miled in a planetary bal mil for 200 minutes with 0.5 mm beads. The slurry was dried in a Yamato spray dryer. A 12 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 765°C for 2 h, then cooled, to provide 10 g of a fine black powder. The XRD diffractogram of the product shows phase- pure LMFP, containing no residual oxidized impurities and less than 1.9% trace impurities. A residual carbon layer remained after heat treatment: the final powder contained 1.51% carbon by weight, as measured by C/S combustion elemental analysis. Further, the powder’s electrical conductivity, measured on a powder pelet compacted at 20 MPa by a four-point probe, was 133 ohm*cm. The powder was formed into a cathode sheet by formulation into a 95:2.5:2.5 slurry with conductive carbon additive and poly(vinylidene fluoride) binder combined in NMP which was coated and dried onto an aluminum foil backing. Circular punches of this sheet were assembled into coin cels with Celgard separators, lithium metal anodes, and 1.2M LiPF6 in EC:EMC (3:7 w/w) plus 2wt% vinylene carbonate electrolyte. The coin cels had a specific discharge capacity of 113 mAh/g at C/5 when cycled from 2.5-4.4V. The powder metrology and electrochemical data demonstrate that (1) the carbon coating is wel-distributed over the LMFP particles, (2) it is sufficiently electricaly conductive to yield good electrochemistry, and (3) it does not deleteriously affect the processability of the cathode into an electrode. Thus, the invention disclosed herein can, starting with previously unusable material, generate cathode material useful in lithium-ion bateries. See Fig.6 and Fig.7. [0135] Example 6: [0136] Starting Material: A fusion-synthesized sample of LMFP was generated for use whose compositional analysis by PXRD indicated the crystaline fraction contained 20% oxidized impurities by weight (80% LMFP, 18% Li3Fe2(PO4)3, 0.5% Li3PO4, and 1.5% metal pyrophosphates). It has no carbon content. Because of its substantial oxidized impurities and lack of carbon, the LMFP sample synthesized herein is not a useful cathode material. Therefore, we have applied the invention disclosed herein to remedy the material. 22 102268356.1 Docket No.113544-838846 [0137] The solid was ground and jet miled until 99% of the mass had a particle size less than 11.2 um as measured by dry laser diffraction particle size analysis. This dry miled powder (380g) was combined with glucose (15.2 g), polyethylene glycol (15.2 g), polyvinylpyrrolidone (3.8 g), titanium dioxide (1.14 g), iron oxalate dihydrate (4.4 g), lithium carbonate (3.6 g), manganese oxalate dihydrate (6.5 g), magnesium acetate tetrahydrate (7.8 g), and water (887 g). The resulting slurry was miled in a horizontal disk mil with 0.3 mm beads. The slurry was dried in a Mobile Minor spray dryer. A 12 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 765°C for 2 h, then cooled, to provide 10 g of a fine black powder. The XRD diffractogram of the product shows phase-pure LMFP, containing no residual oxidized impurities and less than 1.9% trace impurities. A residual carbon layer remained after heat treatment: the final powder contained 1.47% carbon by weight, as measured by C/S combustion elemental analysis. Further, the powder’s electrical conductivity, measured on a powder pelet compacted at 20 MPa by a four-point probe, was 42 ohm*cm. The powder was formed into a cathode sheet by formulation into a 90:5:5 slurry with conductive carbon additive and poly(vinylidene fluoride) binder combined in NMP which was coated and dried onto an aluminum foil backing. Circular punches of this sheet were assembled into coin cels with Celgard separators, lithium metal anodes, and 1.2M LiPF6 in EC:EMC (3:7 w/w) plus 2wt% vinylene carbonate electrolyte. The coin cels had a specific discharge capacity of 113 mAh/g at C/5 when cycled from 2.5-4.4V. The powder metrology and electrochemical data demonstrate that (1) the carbon coating is wel-distributed over the LMFP particles, (2) it is sufficiently electricaly conductive to yield good electrochemistry, and (3) it does not deleteriously affect the processability of the cathode into an electrode. Thus, the invention disclosed herein can, starting with previously unusable material, generate cathode material useful in lithium-ion bateries. See Fig.8 and Fig.9. [0138] Example 7: [0139] Starting Material: A fusion-synthesized sample of LFP was generated for use whose compositional analysis by PXRD indicated the crystaline fraction contained 22% oxidized impurities by weight (78% LFP, 18% Li3Fe2(PO4)3, 4% Fe2O3). [0140] The LFP solid was ground and dry miled until 99% of the mass had a particle size less than 11.2 um as measured by dry laser diffraction particle size analysis. This dry miled powder (36.00 g) was combined with glucose (2.16 g) and deionized water (84 g), and the resulting slurry was miled in a Fritsch planetary mil for 6 h with 0.3mm beads. The slurry was dried in a Yamato spray dryer with an atomizing pressure, blower rate, inlet temperature, and outlet temperature of 0.2 MPa, 0.5 m3/min, 160ºC, and 105ºC, respectively, and 12.7 g of spray dried powder was recovered. A 10.0 g portion of the spray dried powder in a graphite crucible was heated in a nitrogen-purged Linn furnace at 8°C/min to a hold temperature of 700 °C for 1 h, then cooled, to provide 8.9 g of a fine black powder. The XRD diffractogram of the product shows 23 102268356.1 Docket No.113544-838846 phase-pure LMFP, containing no residual oxidized impurities and less than 1.9% trace impurities. A residual carbon layer remained after heat treatment. The powder was formed into a cathode sheet by formulation into a 90:5:5 slurry with conductive carbon additive and poly(vinylidene fluoride) binder combined in NMP which was coated and dried onto an aluminum foil backing. Circular punches of this sheet were assembled into coin cels with Celgard separators, lithium metal anodes, and 1.2M LiPF6 in EC:EMC (3:7 w/w) plus 2wt% vinylene carbonate electrolyte. The coin cels had a specific discharge capacity of 158 mAh/g at C/25 and 148 mAh/g at 1C when cycled from 2.5-3.8V, demonstrating useful performance of these materials in lithium-ion bateries. See Fig.10 and Fig.11. [0141] Although the invention has been described with reference to the disclosed embodiments, those skiled in the art wil readily appreciate that the specific examples and studies detailed above are only ilustrative of the invention. It should be understood that various modifications can be made without departing from the spirit of the invention. DEFINITIONS [0142] Al publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application were specificaly and individualy indicated to be incorporated by reference. [0143] The terms “comprising,” “including,” “having” and their derivatives, are not intended to exclude the presence of any additional component, step, or procedure, whether or not the same is specificaly disclosed. In order to avoid any doubt, al compositions claimed through use of the term “comprising” may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. [0144] The term “or” unless stated otherwise, refers to the listed members individualy as wel as in any combination. Use of the singular includes use of the plural and vice versa. [0145] The terms “a,” “an,” “the” and similar referents used in the context of describing the inventive features (especialy in the context of the folowing claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Thus, for example, reference to a “starch” may include one, two or more starches. [0146] The term “method” refers to a sequence of steps performed to complete a process. [0147] The term “composition” refers to a mixture of materials which comprise the composition, as wel as reaction products and decomposition products formed from the materials of the composition. 24 102268356.1 Docket No.113544-838846 [0148] The term “≤” as used herein refers to a quantitative measure which is interpreted as “less than or equal to.” [0149] The term “micron,” “micrometer,” “μm” or “micrometers” refers to refers to a unit of measure which is equal to one thousand meters. The term “sub-micron” refers to “to a quantitative measure less than a micron or less than 1 micrometer.” With respect to the present invention the term is used to define particle size. [0150] The term “nm,” “nanometers, “or “nanometer” refers to a unit of length which is one thousand- milionth of a meter. With respect to the present invention the term is used to define particle size. [0151] The term “additives,” “additional compounds,” “agents” al refer to “one or more additional compounds,” as described herein. [0152] The term “substantialy free of” used in reference to oxidized impurities refers to less than 5%, less than 1%, less than 0.5%, less than 0.2%, or less than 0.1%. [0153] The term “LMP” used in reference to olivine-type material refers to “lithium-transition metal- phosphate.” As used herein, “LFP” refers to “lithium iron phosphate.” As used herein, “LMFP” refers to “lithium manganese iron phosphate.” [0154] “Capacity” of a batery or batery cel is a measure of the charge stored by the batery and is determined by the active materials contained in the batery. The capacity represents the maximum amount of charge that can be extracted from the batery under certain specified conditions. The batery has a discharge current in amperes that can be delivered over time. The capacity of the batery is given in ampere-hours (Ah). [0155] “D50” and/or “d50” as used herein is a measurement of the average particle size in a group of particles. For example, as used in reference to the size of particles in the LMP powder, dry miled particles, primary particles, and/or secondary particles. [0156] “Gravimetric capacity” is the capacity per unit mass (mAh/g). Gravimetric capacity is also referred to as specific discharge capacity. [0157] Unless otherwise stated, al percentages, ratios, parts, and amounts used and described herein are by weight. [0158] Numbers, percentages, ratios, or other values stated herein may include that value, and also other values that are about or approximately the stated value, as would be appreciated by one of ordinary skil in the art. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result, and/or values that 25 102268356.1 Docket No.113544-838846 round to the stated value. The stated values include at least the variation to be expected in a typical manufacturing process, and may include values that are within 25%, 15%, 10%, within 5%, within 1%, etc. of a stated value. [0159] “wt%” as used herein refers to the percent ratio of the mass of the non-fluid particles or dissolved solids relative to the total mass of said mixture. For example, mass of the carbon-containing compounds, and/or additional compounds in a given mixture relative to the total mass of the olivine-type LMP material. [0160] Unless defined otherwise, al technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skil in the art to which this disclosure belongs. The initial definition provided for a group or term herein applies to that group or term throughout the present specification individualy or as part of another group unless otherwise indicated. 26 102268356.1

Claims

Docket No.113544-838846 CLAIMS 1.A method for decreasing oxidation impurities in an olivine-type lithium-transition metal-phosphate (LMP) material, the method comprising: dry miling particles of the olivine-type LMP material to obtain a dry miled LMP powder, wherein the olivine-type LMP material comprises oxidation impurities; obtaining a dry miled LMP powder; adding a carbon-containing compound to the dry miled LMP powder to form a mixture; miling the LMP material and the carbon-containing compound mixture with a liquid medium to form a wet-miled slurry; drying the wet-miled slurry to yield primary particles comprising particles of the olivine- type LMP material and the carbon-containing compound; wherein the primary particles have a d50 ranging from about 50 nm to about 5000 nm; and calcining the primary particles to produce carbon-coated secondary particles comprising LMP having a d50 ranging from about 50 nm to about 5000 nm; wherein the LMP in the secondary particles has a decreased oxidation impurity content. 2.The method of claim 1, wherein the LMP is a compound having the formula: Li1+x1(M)x2PO4 wherein: M= one or more of Fe and Mn; x1= 0-0.1; and x2= 0.8-1.0. 3.The method of claim 2, wherein the LMP compound further comprises a dopant (A), and has the folowing formula: Li1+x1(MA)x2PO4 wherein: 27 102268356.1 Docket No.113544-838846 M= one or more of Fe and Mn; x1= 0-0.1; x2= 0.8-1.0; and A= one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. 4.The method of claim 1, wherein the LMP is a compound having the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4 wherein: x1= 0-0.1; x2= 0.9-1.0; y = 0.5-0.8; z= 0.0-0.1; and A= one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. 5.The method of claim 1, wherein the LMP is a compound having the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4 wherein: x1= 0.01-0.06 x2= 0.9-1.0 y = 0.6-0.7 z= 0.0-0.05 A= one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. 6.The method of claim 1, wherein the LMP is a compound having the formula: LixMyPO4 wherein: M= one or more of Fe, Ti, and Mg; x= 0.9-1.1; and 28 102268356.1 Docket No.113544-838846 y = 0.9-1.0. 7.The method of claim 1, wherein the LMP is a compound having the formula: LixFeyAzPO4 wherein: x= 0.99-1.02 y = 0.96-1.0 z= 0.00-0.03 A= one or more of Ti and Mg. 8.The method of claim 1, wherein the carbon-containing compound is selected from the group consisting of glucose, sucrose, lactose, maltodextrin, soluble starch, polyethylene glycol, vinyl alcohol, acrylic acid, citric acid, oxalic acid, lauric acid, urea, and combinations thereof. 9.The method of claim 1, further comprising formulating a cathode sheet using the secondary particles; wherein the secondary particles have a d50 ranging from about 100 nm to about 1000 nm. 10.The method of claim 1, wherein the dry miled LMP powder has a d50 of less than or equal to 10 µm. 11.The method of claim 1, wherein the dry miled LMP powder has a d50 ranging from about 400 nm to about 800 nm. 12.The method of claim 1, wherein the carbon-coated secondary particles have a d50 ranging from about 100 nm to about 300 nm. 13.The method of claim 1, wherein the LMP in the secondary particles has an oxidation impurity content of less than or equal to 1% by weight. 14.The method of claim 1, wherein the LMP in the secondary particles has an oxidation impurity content of less than or equal to 0.1% by weight. 15.The method of claim 1, wherein the oxidation impurities are present in an amount of greater than 5% by weight. 29 102268356.1 Docket No.113544-838846 16.The method of claim 1, wherein the liquid medium comprises an organic solvent selected from methanol, ethanol, isopropanol, 2-butanol, acetone, 2-butanone, and combinations thereof. 17.The method of claim 1, wherein the liquid medium is water. 18.The method of claim 1, wherein the wet-miled slurry is dried by a process of spray drying, air drying, or vacuum drying. 19.The method of claim 1, wherein the wet-miled slurry is spray dried with an inlet temperature of about 160 °Cand an outlet temperature of about 105 °C. 20.The method of claim 1, wherein the calcining occurs at a temperature of about 700° C. 21.The method of claim 1, wherein the calcining occurs for about 1 hour. 22.A method for decreasing oxidation impurities in an olivine-type lithium-transition metal-phosphate (LMP) material, the method comprising: dry miling particles of the olivine-type LMP material to obtain a dry miled LMP powder, wherein the olivine-type LMP material comprises oxidation impurities in an amount of greater than 5% by weight; adding a carbon-containing compound to form a mixture with the LMP, the carbon- containing compound selected from the group consisting of glucose, sucrose, lactose, maltodextrin, soluble starch, polyethylene glycol, vinyl alcohol, acrylic acid, citric acid, oxalic acid, lauric acid, urea, and combinations thereof; miling the LMP and carbon-containing compound mixture with a liquid medium to form a wet-miled slurry; drying the wet-miled slurry to yield primary particles comprising particles of the olivine- type LMP material and the carbon-containing compound; wherein the primary particles have a d50 ranging from about 50 nm to about 5000 nm; and calcining the primary particles to produce carbon-coated secondary particles having a d50 ranging from about 50 nm to about 5000 nm; wherein the LMP in the secondary particles has a decreased oxidation impurity content of less than 1% by weight. 23.The method of claim 22, wherein the LMP is a compound having the formula: 30 102268356.1 Docket No.113544-838846 Li1+x1(M)x2PO4 wherein: M= one or more of Fe, Mn, Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, Na; x1= 0-0.1; and x2= 0.8-1.0. 24.The method of claim 23, wherein the LMP compound further comprises a dopant (A), and has the folowing formula: Li1+x1(MA)x2PO4 wherein: M= one or more of Fe and Mn; x1= 0-0.1; x2= 0.8-1.0; and A= one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. 25.The method of claim 22, wherein the LMP is a compound having the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4 wherein: x1= 0-0.1; x2= 0.9-1.0; y = 0.5-0.8; z= 0.0-0.1; and A= one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. 26.The method of claim 22, wherein the LMP is a compound having the formula: Li1+x1(Fe1-y-zMnyAz)x2PO4 wherein: x1= 0.01-0.06 31 102268356.1 Docket No.113544-838846 x2= 0.9-1.0 y = 0.6-0.7 z= 0.0-0.05 A= one or more of Zn, Mg, Zr, Ti, V, Nb, Al, Ni, Co, Cr, Cu, and Na. 27.The method of claim 22, wherein the LMP is a compound having the formula: LixMyPO4 wherein: M= one or more of Fe, Ti, and Mg; x= 0.9-1.1; and y = 0.9-1.0. 28.The method of claim 22, wherein the LMP is a compound having the formula: LixFeyAzPO4 wherein: x= 0.99-1.02 y = 0.96-1.0 z= 0.00-0.03 A= one or more of Ti and Mg. 32 102268356.1