Cathode material and method of forming it

Abstract

A composite powder is useful for making cathodes and is comprised of cathode material particles coated by carbon and a stabilizer such as carboxymethylcellulose or salt thereof. The composite powder may be made by a milling a slurry comprised of a polar solvent (e.g., water) having therein cathode material particles, carbon particles and a stabilizer to form a milled mixture, the cathode material particle's specific surface area in m2 / g being at least an order magnitude less than the carbon particles' specific surface area in m2 / g, and removing the solvent to form a dried mixture comprised of secondary particles of milled disordered rocksalt particles coated with milled carbon particles and stabilizer.

Description

WCAT-193-B-WO CATHODE MATERIAL AND METHOD OF FORMING IT CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a PCT International application which claims priority to U.S. Provisional Patent Application Number 63 / 549,069 filed on February 2, 2024, and U.S. Provisional Patent Application Number 63 / 707,876 filed on October 16, 2024, which are incorporated herein by reference in their entirety for all purposes. FIELD

[0002] The present invention is in the field of battery technology. BACKGROUND

[0003] Lithium metal oxides lithium metal phosphates have been used to formulate cathode materials for lithium ion batteries. The cathodes have utilized a few basic crystallographic structure types, such as spinels, olivines, and layered oxide structures. The layered oxide structures have included lithium-excess type structures, where additional lithium is present in the structure.

[0004] Generally, the lithium metal oxide and phosphates have been mixed with carbon to improve the electrical conductivity of the cathode material when coated onto a metal foil to form the cathode. When doing so a binder such as fluoropolymers typically have been used that have been dissolved in a polar aprotic solvent. The polar aprotic solvents such as methyl-2- pyrrolidinone have been utilized to avoid deleteriously altering the chemistry of the cathode materials in the presence of water and to realize good distribution of the fluoropolymer binder when depositing on metal foil.

[0005] Accordingly, it would be desirable to provide a cathode material particle that avoids one or more problems of in the art such as described above and in particular allows for the processing of the cathode materials in air or water without loss in performance.WCAT-193-B-WO BRIEF SUMMARY

[0006] We discovered that improvements to cathode material compositions comprised of cathode materials such as lithium metal oxide (LMO), lithium metal sulfate (LMS) or lithium metal phosphate (LMP) powder and carbon may be realized by milling in a polar solvent as synthesized / unmilled cathode material particles, carbon particles and a stabilizer sufficiently to realize a carbon coated cathode material particle, which may be agglomerated into a secondary particle. To realize the desired cathode material coated powder with the desired phase purity, lack of formation of undesired compounds (e.g., lithium carbonate) and battery performance, generally requires the cathode material powder to be substantially larger than the carbon in the presence of a stabilizer. It is believed, without being limiting, that during the simultaneous milling of the smaller carbon and cathode material powder in the presence of a stabilizer and in particular a stabilizer comprised of a carboxymethylcellulose a desirable coating of the newly fractured surfaces of the cathode material powder are coated and protected with carbon and stabilizer and realize desirable electrical connection. The cathode material and carbon milled particles, may then be agglomerated by any suitable method such as spray drying to form secondary particles of the milled cathode material powder, stabilizer and carbon to form higher density secondary particles having desirable electronic conductivity and battery performance. It also has been discovered that the cathode material powder may be mixed solely with the stabilizer and then subject to heating in a non-oxidizing atmosphere to cause the stabilizer to carburize forming a carbon coating of the cathode material powder. In addition, the cathode material powder thereof may be cast from the polar solvent after milling or intensive mixing on to a metal foil directly and the polar solvent such as water being removed where the stabilizer or other soluble binder binds the coated cathode material powder to the metal foil forming the cathode.

[0007] An illustration is a method comprising, (i) milling a slurry comprised of a polar solvent having therein particles comprised of a cathode material powder, carbon particles and a stabilizer to form a milled mixture, the cathode material powder’s specific surface area in m2 / g being at least an order magnitude less than the carbon particles’ specific surface area in m2 / g and (ii) removing the solvent to form a dried mixture comprised of secondary particles of milled 2 4894-0899-6840, v.3WCAT-193-B-WO cathode material powder particles coated with milled carbon particles and stabilizer having a specific surface area of about 1, 2, 5 or10 m2 / g to 30, 40 or 50 m2 / g. Surprisingly the solvent may be water particularly when the stabilizer is comprised of a carboxymethylcellulose or salt thereof. The cathode material may be LMO, LMP or combination thereof.

[0008] An illustration is a composite powder comprised of a cathode material powder coated with carbon and a stabilizer comprised of carboxymethylcellulose. The composite powder having a specific surface area of 1, 5, or 10 m2 / g to 50 m2 / g and the cathode material particles comprising from 90% to 99% by weight of the composite powder have been found to be particularly useful.

[0009] An illustration is a method comprising, (i) milling a slurry comprised of a polar solvent having therein cathode material particles, carbon particles and a stabilizer to a milling energy of 200 kWh / t to 700 kWh / t to form a milled mixture and (ii) removing the polar solvent to form a dried mixture comprised of secondary particles of composite particles comprised of milled cathode material particles coated with milled carbon particles and stabilizer. The secondary particles may then be dispersed with other components useful to make a cathode (e.g., a binder) in a liquid such as a polar solvent (e.g., solvent comprised of water of any useful pH such as described herein) under agitation insufficient to deagglomerate the secondary particles, cast upon a metal foil and removal of the liquid to form a cathode for use in a battery. Insufficient means that the agitation is of a shear that fails to cause the secondary particles to be broken down to its primary particles retaining the shape of the secondary particles with at most about 10%, 5% or 1 % by number of the secondary particles being fractured. Alternatively, the secondary particles average particle size after mixing is at most 20%, 15% or 10% smaller than the secondary particles average particles size prior to mixing. The average particle size may be determined by a method described herein.

[0010] An illustration is a method to form composite particles comprising mixing a cathode material powder, a particulate carbon and a stabilizer comprised of a carboxymethylcellulose in a liquid, removing the liquid to form coated particles comprised of cathode material particles coated with the stabilizer, heating the coated particles to a carburizing temperature in an atmosphere sufficient to carburize the stabilizer to form composite particles comprised of 3 4894-0899-6840, v.3WCAT-193-B-WO cathode material particles coated with carbon. Desirably, the carbon coating is comprised of amorphous carbon realized from the carburization of the stabilizer and particulate carbon that is graphitic.

[0011] An illustration is a method of forming a cathode comprising mixing any of the aforementioned composite particles with a liquid (e.g., polar solvent with water being an example) to form a slurry, depositing the slurry onto a metal foil and removing the liquid to form the cathode. In an illustration, the cathode may be heated to a carburizing temperature in a non- oxidizing atmosphere to a temperature to carburize at least a portion of the stabilizer used to make the composite particles. In another illustration, the slurry is formed using secondary particles of the composite particles under agitation insufficient to deagglomerate the secondary particles prior to depositing on to the metal foil.

[0012] The composite powder (composite particles used herein interchangeably) or secondary particles of the composite powder may be used in a cathode in a primary and secondary battery such as a lithium ion battery. A cathode comprised of the composite powder may be used with any suitable electrolyte, separator and anode such as those known in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a plot of the surface area of disordered rocksalt particles coated of this invention with carbon and stabilizer as a function of milling energy.

[0014] Figure 2 is a is a plot of the average crystallite size of disordered rocksalt particles coated with carbon and stabilizer as a function of milling energy.

[0015] Figure 3 is a plot of the tap density of disordered rock salt particles coated with carbon and stabilizer as a function of milling energy.

[0016] Figure 4 displays the X-ray diffraction patterns of the disordered rock salt particles coated with carbon milled at differing milling energies.

[0017] Figure 5 is a scanning electron micrograph (SEM) of secondary particles of disordered rocksalt primary particles coated with carbon and stabilizer of this invention. 4 4894-0899-6840, v.3WCAT-193-B-WO

[0018] Figure 6 is a scanning electron micrograph (SEM) of secondary particles of disordered rocksalt primary particles coated with carbon and stabilizer of this invention.

[0019] Figure 7 is a plot showing the cycle 1 capacity of batteries made from coated disordered rocksalt composite powders of this invention that were heat treated at differing temperatures.

[0020] Figure 8 is a plot showing the cycle 1 coulombic efficiency of batteries made from coated disordered rocksalt composite powders of this invention that were heat treated at differing temperatures.

[0021] Figure 9 are plots of the capacity of batteries made from coated disordered rocksalt composite powders of this invention versus cycle number.

[0022] Figure 10 are plots of the capacity retention of batteries made from coated disordered rocksalt composite powders of this invention versus cycle number.

[0023] Figure 11 is a plot showing the cycle 1 capacity of batteries made from coated disordered rocksalt composite powders of this invention and not of this invention.

[0024] Figure 12 is a plot showing the cycle 1 coulombic efficiency of batteries made from coated disordered rocksalt composite powders of this invention and not of this invention.

[0025] Figure 13 are plots of the capacity of batteries made from coated disordered rocksalt composite powders of this invention and not of this invention versus cycle number.

[0026] Figure 14 are plots of the capacity retention of batteries made from coated disordered rocksalt composite powder of this invention and not of this invention versus cycle number.

[0027] Figure 15 is a plot of the cycle 1 capacity of a battery made from a coated disordered rocksalt composite powder not of this invention.

[0028] Figure 16 is a plot of the cycle 1 capacity v. V of a battery made from a coated disordered rocksalt composite powder not of this invention. 5 4894-0899-6840, v.3WCAT-193-B-WO DETAILED DESCRIPTION

[0029] The following definitions apply to some of the aspects described with respect to some embodiments of the invention. These definitions may likewise be expanded upon herein. Each term is further explained and exemplified throughout the description, figures, and examples. Any interpretation of the terms in this description should take into account the full description, figures, and examples presented herein. It is understood that any reference to a property or characteristic of a material may be determined by any suitable methods such as commonly used methods and standards for such characteristics. For example, if the specific surface area is of a material is described, it would be acceptable to use the common nitrogen adsorption isotherm method referred to as BET (Brunauer-Emmet-Teller) method, without citing the particular standard (i.e., ISO 9277).

[0030] When a majority is specified of a component, it means more than 50% by mole or (readily understood from the context used) to essentially all of that component (99% or less). That is, the majority specified constituent of a component is present in an amount greater than 50% to 99%, 90, 80%, 70% or 60% of that component. When a minority of a component is a specified constituent, it is present in an amount less than 50% to about 1% with the balance being the majority specified constituent.

[0031] The singular terms “a,” “an,” and “the” include the plural unless the context clearly dictates otherwise. Thus, for example, reference to an object can include multiple objects unless the context clearly dictates otherwise.

[0032] A rate “C” refers to either (depending on context) the discharge current as a fraction or multiple relative to a “1 C” current value under which a battery (in a substantially fully charged state) would substantially fully discharge in one hour, or the charge current as a fraction or multiple relative to a “1 C” current value under which the battery (in a substantially fully discharged state) would substantially fully charge in one hour.

[0033] To the extent certain battery characteristics can vary with temperature, such characteristics are specified at 30 degrees C, unless the context clearly dictates otherwise. 6 4894-0899-6840, v.3WCAT-193-B-WO

[0034] Ranges presented herein are inclusive of their endpoints. Thus, for example, the range 1 to 3 includes the values 1 and 3 as well as the intermediate values.

[0035] In one illustration to form the composite powder, a cathode material powder that is substantially larger in size than a particulate carbon is milled in a polar solvent in the presence of a stabilizer. Illustratively, the specific surface area of the carbon is at least 10 times, 15 times, 20 times, 50 times, or 100 times to 500 times, 250 times or 200 times greater than the specific surface area of the cathode material powder.

[0036] The cathode material may be any useful cathode material suitable to intercalate lithium in a secondary battery such as those known in the art. Illustratively, the cathode material may be a lithium transition metal oxide, a transition metal sulfide, and the like. The cathode may include any material sufficient to have desirable discharge capacity and charge retention when used with an anode. Examples of suitable cathode materials may include phosphates, fluorophosphates, fluorosulfates, fluorosilicates, spinels, lithium-rich layered oxides, and composite layered oxides. Further examples of suitable cathode materials may include spinel structure lithium metal oxides, layered structure lithium metal oxides, lithium-rich layered structured lithium metal oxides, lithium metal silicates, lithium metal phosphates, metal fluorides, metal oxides, sulfur, metal sulfides, disordered rock salt structures, or any combination thereof.

[0037] Illustratively, the positive electrode material may be at least one complex oxide of lithium and a metal selected from cobalt (Co), nickel (Ni), and a combination thereof, and 65 more particularly, a compound represented by at least one Formula of LiaA1-bBbD2(wherein, 0.90≤l.8 and 0≤b≤0.5); LiaE1-bBbO2-cDc(wherein, 0.90≤a≤l.8, 0≤b≤0.5, 0≤c≤0.05); LiE2-bBbO4-cDc (wherein, 0≤b≤0.5, 0≤c≤0.05); LiaNi1-b-cCobBcDα (wherein, 0.90≤a≤l .8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); LiaNil-b-cCobBcO2-aF^ (wherein, 0.90≤a≤l.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); LiaNi1-b-cCobBcO2-αFα (wherein, 0.90≤a≤l.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); LiaNi1-b-cMnbBcDα (wherein, 0.90≤a≤l.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); LiaNil-b-cMnbBcO2-αFα(wherein, 0.90≤a≤l.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); LiaNibEcGdO2(wherein, 0.90≤a≤l.8, 0≤b≤0.9, 0≤c≤0.5, 0.00l≤d≤0.1); LiaNibCocMndGeO2 (wherein, 0.90≤a≤l .8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5); LiaNiGbO2(wherein, 0.90≤a≤l.8, 0.00l≤b≤0.1.); LiaCoGbO2(wherein, 0.90≤a≤l.8, 0.00l≤b≤0.1); LiaMnGbO2 (wherein, 0.90≤a≤l.8, 0.00l≤b≤0.1); LiaMn2GbO4(wherein, 0.90≤a≤l.8, 7 4894-0899-6840, v.3WCAT-193-B-WO 0.00l≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O2; LiIO2; LiNiVO4; Li(3-f)J2PO4)3(wherein 0≤f≤2); Li(3-f)Fe2(PO4)3(wherein 0≤f≤2); and LiFePO4.

[0038] In the formulae above, A is Ni, Co, manganese (Mn), or a combination thereof; B is aluminum (Al), Ni, Co, Mn, chromium (Cr), iron (Fe), strontium (Sr), vanadium (V), or a combination thereof; D is oxygen (0), fluorine (F), sulfur (S), phosphorus (P), or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, magnesium (Mg), lanthanum (La), Cerium (Ce), Sr, V, or a combination thereof; Q is titanium (Ti), molybdenum (Mo), Mn, or a combination thereof; I is Cr, V, Fe, scandium (Sc), yttrium (Y), or a combination thereof; J is V, Cr, Mn, Co, Ni, copper (Cu), or a combination thereof.

[0039] Desirably, the cathode is a lithium metal phosphate or lithium oxide comprised of Ni, Mn, and Co (NMC). The NMC desirably is one having at least 50%, 60%, 70% or 75% by mole Ni of the total moles of the Ni, Mn and Co present in the NMC. Preferably, the NMC is a layered oxide.

[0040] In a particular embodiment, the cathode material may be comprised of a disordered rocksalt DR. DR is a compound where both lithium and a transition metal occupy a cubic close- packed lattice of octahedral sites. In electrochemical reactions, lithium diffusion proceeds by the lithium hopping from one octahedral site to another octahedral site via an intermediate tetrahedral site. Lithium in the intermediate tetrahedral site is the activated state in lithium diffusion. The activated tetrahedral lithium ion shares faces with four octahedral sites as follows: (i) the site previously occupied by the lithium ion itself; (ii) the vacancy the lithium ion will move into; and (iii & iv) two sites that can be occupied by lithium, a transition metal, or a vacancy.

[0041] An example of a disordered rocksalt (DR) is one having a formula: LixM’yMzO2-(a+b)FaZbwhere 1.0<x<1.75; 0≤y<0.55; 0.1<z<1; 0≤(a+b)≤0.7; (b≥0) M’ is one of Ti, Ta, Zr, W, Nb, or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, Sn, Bi and Sb; Z is one or more of P, N and S. Further dopants may be included such as those substituting 8 4894-0899-6840, v.3WCAT-193-B-WO for Li such as Na and Mg, which may be at any useful amount, but generally are at most about 10% or 5% to 0.01% by mole of the lithium and such dopants present in the DR.

[0042] The amount of F and Z, when present, may be a majority or minority of the anion (i.e., O, F and one or more of P, S and N). Illustratively (a+b) is 0.05 to 1.5, 1, 0.95, 0.8, 0.65, 0.5. It may be desirable for a to be 0.05 to 0.25. Z may be any combination of P, N and S, or may be just one of them. The ratio between P, N and S when two or more are present may be any useful ratio depending on the attributes sought. For example, it may be desirable to have S present when a reduced redox potential is desired. It may also be desirable for S to be the majority of the P, S and N present in the composition.

[0043] The DR may have any desirable Li of 1 or above, but it may be desirable for Li as represented by x to be at least 1.1, 1.15, 1.2 to 1.65, 1.5 or 1.4.

[0044] The cation of the DR may be the metals described, but desirably, at least one of the metals as represented by M is comprised of one or more of Ti, Mn, Fe, Co,V, Cr, Ni and Cu. It may be desirable for M to be comprised of Ti and Mn. The composition may illustratively be one where M’ is comprised of Nb. When Nb is present, it may desirable for M to be comprised of Mn. Illustratively, M’ may be Nb and M may be Mn. When Nb and Mn are present with or without other metals, they may be present in a ratio of Mn / Nb of 1 or 2 to 200, 150, 100, 75, 50, 25 or 10 by mole.

[0045] The DR may be made by any suitable method such as those known in the art to make disordered rocksalts. Illustrative methods are described in U.S. Pat. Nos.10,280,092, 10,978,706 and ACS Appl Mater Interfaces.2019 Oct 2;11(39):35777-35787, each incorporated herein by reference.

[0046] The cathode material prior to milling with the carbon and stabilizer in water desirably has an average particle size greater than about 0.5 micrometer, 1 micrometer, or 2 micrometers to about 20 micrometers, 15 micrometers or 10 micrometers equivalent spherical diameter. More particularly, the size of the cathode material particles as given by the specific surface area illustratively is at most 1 m2 / g, 0.75 m2 / g 0.5 m2 / g to 0.05 m2 / g, 0.1 m2 / g or 0.2 m2 / g prior to 9 4894-0899-6840, v.3WCAT-193-B-WO milling with the carbon. The specific surface area may be determined by a single point nitrogen BET method as described herein.

[0047] The amount of cathode material particles in the slurry is at least about 80%, 85%, 90% or 92%, to 96%, 97% 98% or 99% by weight of the cathode material particles, carbon particles and stabilizer present in the slurry. The carbon particles and stabilizer may be present at useful ratio within the slurry to realize the desired battery performance, with useful carbon particles / stabilizer weight ratios being from 0 (only stabilizer present, when further carburizing is contemplated to form the carbon solely from the stabilizer such as CMC described herein), 0.1, 0.2, 0.5, 0.75 to 1.5, 2, 3, 5 or 10. The total amount of the cathode material particles, carbon particles and stabilizer may be any useful amount to efficiently mill the cathode material particles, carbon particles and effectuate the stabilizer. Illustratively, the amount of these present in the solvent typically is at least about 1%, 5%, 10% to any practical amount that allows for the effective milling without clogging and the like, with 50%, 40%, 30% or 20% by weight or volume being common upper limits depending on the particular milling method and solvent used.

[0048] The carbon particles may be any suitable carbon such as those known in the art. Exemplary carbon particles include carbon black, carbon nanotubes, graphene, graphite, carbon fiber, and acetylene black. Illustratively, the carbon particles are carbon black powders that may be standard conductive or non-conductive. The carbon may be comprised of primary particles that are chemically bound into secondary particles (e.g., carbon black) and referred to as structured inorganic powders or the primary particles may not be chemically bound other than by hydrogen or Van-der Waals forces (e.g., carbon nanotubes). The particle size may be determined as previously described. The carbon particles may have any useful oil absorption number (ASTM D-2414-09). For example, the carbon particles such as carbon black typically should have an oil absorption number (OAN) of about 40, 50, or 60 to 250, 200 or 175 mls per 100 grams. The specific surface area of the carbon particles, such as carbon nanotubes and in particular single wall carbon nanotubes, double walled carbon nanotubes or mixture thereof, may be any useful, and generally is at least 10 m2 / g, 20 m2 / g or 50 m2 / g to any practical surface area, 1000 m2 / g, 500 m2 / g, 300 m2 / g or 150 m2 / g. Exemplary single wall / double wall carbon nanotubes such as produced by chemical vapor deposition (CVD) methods include those 10 4894-0899-6840, v.3WCAT-193-B-WO available under the tradename TUBALL from OCSiAl USA, Gahanna, OH and CVD SW / DW nanotubes available from Cheap Tubes Inc., Grafton, Vt.

[0049] The carbon black may be a standard carbon black which is not specially treated to render it nonconductive. Standard carbon black is carbon black which is not specifically surface treated or oxidized. Alternatively, one or more conductive carbon blacks may be used exclusively or in conjunction with the standard carbon black. Conductive carbon blacks are generally recognized as having at a purity of at least 97% carbon, but preferably may be 99% or greater in purity, OAN of 100 or greater and specific surface area of 120 m2 / g or greater. Examples of standard carbon blacks include RAVEN 790, RAVEN 450, RAVEN 500, RAVEN 430, RAVEN 420 and RAVEN 410 carbon blacks available from Colombian and carbon blacks available from Cabot Corporation under the tradenames VULCAN, PROPEL, REGAL, STERLING, and SPHERON.

[0050] The stabilizer may be any suitable that results in the coating of the milled cathode material particles by the carbon and stabilizer or the stabilizer alone. Illustratively, the stabilizer is desirably comprised of carboxymethycellulose (CMC) or salt thereof. The CMC or salt thereof may be any suitable such as those known in the art and may have any useful weight average molecular weight (Mw) with commercially available CMC having an Mw of 10,000 to 1,000,000 Daltons being suitable with the method providing sufficient milling to decrease the Mw of the CMC, for example, to less than 200,000150,000 or 100,000 Daltons to 1000 Daltons. Alternatively, lower molecular weight CMCs such as those having a Mw of less than 200,000 Daltons may be used to start with and it may be desirable to have a mixture of high Mw CMC (greater than 500,000 Daltons Mw) and lower molecular weight CMC (at most 200,000 Daltons Mw), for example, to pre-disperse the carbon particles prior to milling.

[0051] The CMC generally has any substitution useful to realize the desired coating of the milled cathode material particles when milled with or without the carbon particles and CMC. The average number of methoxyl groups per anhydroglucose unit in the CMC is designated as the degree of substitution of methoxyl groups (DS). Typically, the DS may be any useful and typically is from 0.4 to fully substituted and may depend on the particular polar solvent employed when milling. Illustratively, the DS may be from 0.4 to fully etherified (3), 1.5, 1.2 or 1. Other substitutions may also be desirable such as those that render the CMC thermoplastic 11 4894-0899-6840, v.3WCAT-193-B-WO and soluble in a particular solvent such as described in U.S. Pat. No.2,831,852. Illustratively, when other substitutions such as a hydroxypropoxyl group as expressed by MS may be any useful amount to disperse the carbon and coat the cathode material particles. MS is the average number of moles of hydroxypropoxyl groups per anhydroglucose unit in the hydroxypropyl methylcellulose. It is to be understood that during the hydroxypropoxylation reaction the hydroxyl group of a hydroxypropoxyl group bound to the cellulose backbone can be further etherified by a methylation agent and / or a hydroxypropoxylation agent. Multiple subsequent hydroxypropoxylation reactions with respect to the same carbon atom position of an anhydroglucose unit yields a side chain, wherein multiple hydroxypropoxyl groups are covalently bound to each other by ether bonds, each side chain as a whole forming a hydroxypropoxyl substituent to the cellulose backbone. The term “hydroxypropoxyl groups” thus has to be interpreted in the context of the MS as referring to the hydroxypropoxyl groups as the constituting units of hydroxypropoxyl substituents, which either comprise a single hydroxypropoxyl group or a side chain as outlined above, wherein two or more hydroxypropoxyl units are covalently bound to each other by ether bonding. Within this definition it is not important whether the terminal hydroxyl group of a hydroxypropoxyl substituent is further methylated or not; both methylated and non-methylated hydroxypropoxyl substituents are included for the determination of MS. The MS, when other substituents are present such as hydroxypropoxyl substituents may any useful and typically is at least 0.5 or 1 to 2.1, 2.4 or 2.5.

[0052] The determination of the % methoxyl and % hydroxypropoxyl may be carried out according to the United States Pharmacopeia (USP 35, “Hypromellose”, pages 3467-3469). The values obtained are % methoxyl and % hydroxypropoxyl. These may subsequently be converted into degree of substitution (DS) for methoxyl substituents and molar substitution (MS) for hydroxypropoxyl substituents. Residual amounts of salt are taken into account in the conversion.

[0053] The CMC may be a purified (i.e., the alkali removed when making the CMC) or the CMC stabilizer may be comprised solely of the salt form of the CMC stabilizer or a mixture thereof. Desirably, at least some of the CMC stabilizer is comprised of the salt such as at least 10%, 20%, 50%, 75% or 90% of the CMC stabilizer being comprised of the salt form of the CMC stabilizer. Illustrations of CMC stabilizers that may be useful include those commercially available under the tradenames CELLOGEN, from Dai-Ichi Kogyl Seiyaku,Co., LTD, Japan, 12 4894-0899-6840, v.3WCAT-193-B-WO AVICEL microcrystalline cellulose and sodium CMC available from Signet Excipients Pvt. Ltd. India as well as those under the tradename TUBALL in suspension with carbon nanotubes. The stabilizer may also be comprised of cellulose that has been rendered dispersible or soluble in water by oxidation mediated by 2,2,6,6-Tetramethylpiperidne-1-oxyl (TEMPO), phosphorylation by phosphoric acid, and sulfonation by sulfuric acid.

[0054] The solvent may be any that is useful for dispersing and milling the cathode material particles, carbon particles and stabilizer and typically is a polar solvent such as those having one or more groups creating a sufficient dipole to realize a dielectric constant of at least 10 and typically less than about 100. Examples of such groups include an ether, carbonyl, ester, alcohol, amine, nitrile, amide, imide, halogen or any combination thereof. The dielectric constant may be calculated from the dipoles present in the solvent molecule or determined experimentally such as described in J. Phys. Chem. C 2017, 121, 2, 1025–1031. Water or mixture of water with a polar solvent are preferred, with the pH of the water being neutral or weakly basic (e.g., pH 7 to 16) and the water may be neutral to start the milling and due to chemistry of the cathode material particles may form a slightly basic solution.

[0055] The slurry may also be comprised of a carbon precursor or binder (organic compound) such as fluorocarbon polymer described herein. Other organic compounds that form carbon at the desired carburizing temperature (carbon precursor) that may act as a binder as well. The carbon precursor may only be partially carburized at the carburizing temperature as described for the stabilizer. The carbon precursor desirably has a low decomposition temperature (e.g., below about 200 ℃) that is referred to herein as a low temperature decomposing (LTD) carbon precursor. The LTD carbon precursor may be any that begins decomposing prior to the just mentioned decomposition temperature. Decomposition temperature is when a TGA substantially deviates from linear at a heating rate of 20 ℃ / min and is performed under nitrogen or inert gas in the absence of any other compound. Exemplary LTD carbon precursors may be carboxylic acids or derivatives thereof (e.g., esters). The carboxylic acid may be saturated or unsaturated (e.g., linoleic acid). Desirably, the carboxylic has from 8 to 24 carbon atoms. The carboxylic may also desirably have 2 or more acid or hydroxyl groups to 10 or 6 such groups. 13 4894-0899-6840, v.3WCAT-193-B-WO

[0056] Other precursor compounds may be any useful organic compounds that may decompose to form carbon during the heating to carburizing temperature. It may be desirable for the carbon precursors to be comprised of a nitrogen bearing organic carbon precursor and a hydroxyl bearing organic carbon precursor such as the carboxylic acid described above. The nitrogen bearing precursor illustratively may be an amine or amide. Exemplary nitrogen bearing precursors may include one or more of cyanoguanadine, melamine, urea, hexamethylene tetramine, trimethylamine, diethanolamine, triethanolamine, tetramethylenediamine, acetoguanamine, benzyldimethylamine, methylolmelamine, alkylated methylolmelamine, hexamethoxymethyl melamine, N,N'-dimethyl-p-phenylenediamine, tetraaminobenzene, diaminobenzidine, thiourea, formamide, acetamide, benzamide, oxamide, succinamide, malonamide, guanidine, biuret, triuret, dicyandiamide, biurea, ethylene urea, ammelide, ammeline, aminoguanidine, quaternary ammonium compounds (CTAB, etc.), semicarbazide, thiosemicarbazide, cationic starch (amino modified starch) and acrylamide.

[0057] Exemplary hydroxyl bearing precursors may include sucrose, fructose, glucose, mannose, xylose, raffinose, dextrin, amylose, maltose, lactose, arabinose, dextrose, galactose, amylopectin, glucose polymers (glucans), xylose polymers (xylans), copolymers of glucose and xylose (gluco-xylans), invert sugar, partially invert sugar, molasses from sucrose refining, whey from milk processing, corn syrup, starch, modified starch, cationic starch, and soy protein.

[0058] Other carbon precursors may include polymers or resins such as aromatic containing polymers, resins and compounds that form cross-linked thermoset polymers. Illustratively, the carbon forming material may be a polycarbonate, epoxy, polyimide, polyamide, phenol- formaldehyde resin (e.g., resole and novolac resins), polyacrylonitrile pitch, carbon pitch (distillation product of coal or oil / petroleum tar). Desirably, the carbon pitch is a petroleum pitch having a softening temperature of 100 ℃, 150 ℃, 200 ℃ to 300 ℃, 275 ℃, or 260 ℃ as measured by the method described in ASTM D3104-14a. Examples of pitches having high softening points and high carbon yield that may be useful are described in U.S. Pat. Nos. 4,927,620 and 7,220,348, each incorporated herein by reference. The phenolic resin desirably is a novolac phenolic resin dissolvable in alcohols such as those known in the art with representative examples being described in U.S. Pat. Nos.3,244,671 and 3,299,167 and U.S. Pat. Pub. No.2006 / 0241276. 14 4894-0899-6840, v.3WCAT-193-B-WO

[0059] The milling may be performed by any suitable mill to realize the desired primary particle size of the cathode material particles coated with the carbon particles and stabilizer. Generally, this requires a high energy micromedia mill. The micromedia mill may include concentric cylinders with a milling media (less than 2 mm in size and often referred to as a sand mill) present in an annular gap between the cylinders. The milling media grinds the cathode material particles and carbon particle as the cylinders are rotated relative to each other to create small nano-sized primary particles coated with the carbon particles and stabilize after removing the solvent from the slurry. The micromedia mill may also be designed to form homogenously- sized particles such that all of the primary precursor particles have approximately the same size, within a designated range. The cathode material primary coated particles out of the mill may have an average particle size that is useful for intercalating Li, but desirably the average primary size is no greater than 1 micrometer, 500 nanometers or 400 nanometers (nm). The average primary particle size of each of the cathode material particles coated with carbon and stabilizer may be no greater than 500 nm, 100 nm, or less to any practicable size such as greater than about 25 nm. Illustratively, the milled cathode material particles and carbon particles which may form secondary particles of coated cathode material particles with the carbon particles and stabilizer may have surface area that is at least 5 m2 / g, 10 m2 / g or 20 m2 / g to at most about 100 m2 / g , 60 m2 / g, 50 m2 / g or 40 m2 / g. It has been discovered that the carbon particles should undergo some pulverization to break up structure or reduce size of the nanotubes (e.g., reduce the length) to realize the desired coating of the cathode material particles with the stabilizer and carbon particles.

[0060] In an illustration, the cathode material particles and carbon particles have a surface area of less than 10 m2 / g for a milled input energy of greater than 100 kWh / t or at least 150 kWh / t to at most about 700 kWh / t, 400 kWh / t or 300 kWh / t, which realizes a dried milled secondary cathode material particle coated with carbon particles agglomerated into secondary particles having a surface area described above. Such particles display desirable battery performance and phase purity.

[0061] An example of a suitable micromedia mill is a laboratory bead mill, such as the Buhler PML2 product, which is trademark of the Buhler Group. The size of the particles may be determined, for example, by laser diffraction or image analysis of micrographs of a sufficient 15 4894-0899-6840, v.3WCAT-193-B-WO number of particles (~100 to ~200 particles). A representative laser diffractometer is one produced by Microtrac, such as the Microtrac S3500.

[0062] After milling, the solvents such as water is removed to agglomerate the milled coated cathode material particles. The secondary particles may be formed by any useful method and illustratively may be formed by spray drying. Desirably, the secondary particles (composite powder) have a secondary particle average size of about 1 or 2 micrometers to 20, 15 or 10 micrometers. The spray drying may be performed, for example, using a mini spray dryer, such as the Buchi B-290 model, which is a trademark of Buchi.

[0063] In another illustration, the composite powder may be formed by milling a slurry comprised of the cathode material powder in a solvent with the stabilizer (e.g., the CMC described herein) in the absence of a solid carbon such as those described herein. Other carbon precursors (i.e., organic compounds that upon heating in a non-oxidizing atmosphere forms carbon) may be included in the slurry when milling. After milling the solvent (e.g., polar solvent described herein) is removed and the stabilizer coated cathode material particles with or without further coating by other carbon precursors is heated to an annealing or carburizing temperature to at least carburize a portion of the stabilizer and carbon precursor, if present to form the composite powder. Desirably, the carbon that is formed is essentially amorphous and is present in any suitable amount such as described herein when a solid carbon is present to form the composite powder.

[0064] The composite powder may be used to form a cathode by any suitable method such as those known in the art. For example, the secondary particles of cathode material particles, carbon and stabilizer may be mixed with a binder such a polymer useful to make cathodes (e.g., polyfluoropolymer such as polyvinylidene fluoride “PVDF” and a polyimide) one or more solvents to form a slurry. Non-limiting examples of the one or more solvents may be an aprotic polar solvent such as methyl-2-pyrrolidinone (NMP). The slurry may then be deposited on a metal current collector (e.g., stainless steel, copper, or any suitable conductive metal thin) and the solvent removed to form the cathode. It has been surprisingly discovered that the solvent may be comprised of water using the method to coat the cathode material particles, where the water does not detrimentally affect the chemistry or battery performance of the cathode, which is believed to be due to the carbon coating of the cathode material during milling in the presence of 16 4894-0899-6840, v.3WCAT-193-B-WO the stabilizer (e.g., CMC). The CMC may further act as a binder when the solvent is removed to form the cathode comprised of the composite particles deposited upon a metal foil.

[0065] The composite powder of cathode particles, carbon particles, when present, and stabilizer may be further annealed to a temperature in a non-oxidizing atmosphere comprised of one or more of carbon monoxide, hydrogen, nitrogen and an inert gas (e.g., noble gas), which may improve the performance of a battery made therefrom and may cause at least a portion of the stabilizer (at least 10% , 20%, 35%, 50%, 75%, 90% by weight to essentially all of the stabilizer such as the CMC) to carburize to form an amorphous carbon. Illustratively, the temperature may be from about 200 °C, or 225 °C to 450 °C, 400 °C, 350 °C, 350 °C or 275 °C. The time of the further annealing / carburizing may be any useful to realize the desired performance or carburization of the stabilizer such as 5, 10 or 15 minutes to 24, 18, 12 or 6 hours. Amorphous means that the carbon essentially fails to display graphitic crystallinity in a powder X-ray diffraction pattern. The amount of binder remaining may be determined by solubilization of the remaining organic polymer from the solid amorphous or graphitic carbon. The ratio of the amorphous to graphitic carbon may be any useful to realize a desired electrochemical performance. The amount of amorphous desirably being at least 10%,25%, 50%, 75%, 90%, 99% to all of the carbon.

[0066] The composite powder of cathode particles, carbon particles, when present, and stabilizer may be further annealed to a temperature in an oxidizing atmosphere comprising oxygen or mixture of oxygen with other gas, which may improve the performance of a battery made therefrom and may cause at least a portion of the stabilizer (at least 10% , 20%, 35%, 50%, 75%, 90% by weight to essentially all of the stabilizer such as the CMC) to carburize to form an amorphous carbon and portion of it to oxidize forming gaseous products thus increasing the energy density of a battery by decreasing the total carbon amount. Illustratively, the temperature may be from about 200 °C to 400 °C, 350 °C, 350 °C or 275 °C. The time of the further annealing / carburizing may be any useful to realize the desired performance or carburization / oxidation of the stabilizer such as 5, 10 or 15 minutes to 24, 18, 12 or 6 hours.

[0067] A cathode made of the composition may be used in a rechargeable lithium ion battery cell. The battery cell includes the cathode, an anode, separator and electrolyte. The battery or battery cell may be formed in any suitable atmosphere such as common in the art. For example, 17 4894-0899-6840, v.3WCAT-193-B-WO a high purity argon atmosphere may be used to limit any undesirable contamination from species present in atmospheric air. Illustrations:

[0068] Illustration 1. A method comprising, (i) milling a slurry comprised of a polar solvent having therein cathode material particles, carbon particles and a stabilizer to form a milled mixture, the cathode material particle’s specific surface area in m2 / g being at least an order magnitude less than the carbon particles’ specific surface area in m2 / g, and (ii) removing the solvent to form a dried mixture comprised of secondary particles of milled cathode material particles coated with milled carbon particles and stabilizer.

[0069] Illustration 2. The method of illustration 1, wherein the stabilizer is comprised of carboxymethylcellulose (CMC).

[0070] Illustration 3. The method of illustration 1, wherein the dried mixture has a surface area of at least 1 m2 / g to 40 m2 / g.

[0071] Illustration 4. The method of illustration 1, wherein the carbon particles’ specific surface area is at least 20 times greater than the cathode material particles’ specific surface area.

[0072] Illustration 5. The method of any one of the preceding illustrations, wherein the carbon particles are comprised of one or more of carbon black, carbon nanotubes, graphene, graphite, carbon fiber, and acetylene black.

[0073] Illustration 6. The method of illustration 5, wherein the carbon particles are comprised of single wall carbon nanotubes.

[0074] Illustration 7. The method of either illustration 5 or 6, wherein the carbon particles’ specific surface is at least 50 m2 / g to 200 m2 / g and the cathode materials particles’ specific surface area is from 0.01 m2 / g to 1 m2 / g.

[0075] Illustration 8. The method of any one of the preceding illustrations further comprising one or more of annealing the dried mixture to 200 ℃ to 350 ℃. 18 4894-0899-6840, v.3WCAT-193-B-WO

[0076] Illustration 9. The method of any one of the preceding illustrations, wherein the carbon particles are present in an amount of 1% to 10% by weight of the dried mixture.

[0077] Illustration 10. The method of any one of the preceding illustrations wherein the cathode material is comprised of one or more of a phosphate, fluorophosphate, fluorosulfate, fluorosilicate, spinel, lithium-rich layered oxide, and composite layered oxide.

[0078] Illustration 11. The method of any one of the preceding illustrations, wherein the milled cathode materials primary particles’ average particle size is at most 500 nm and the milled carbon particles’ average primary particle size is less than the milled cathode material particles’ average primary particle size.

[0079] Illustration 12. The method of any one of the preceding illustrations, wherein the removing of the solvent is by spray drying.

[0080] Illustration 13. The method of any one of the preceding illustrations, wherein the solvent is comprised of water having a pH of 7 to 16.

[0081] Illustration 14. The method of illustration 8, wherein the dried mixture is annealed from 225 ℃ to 275 °C.

[0082] Illustration 15. The method of either illustration 8 or 14, wherein the annealing is for a time of 1 to 24 hours under non-oxidizing atmosphere.

[0083] Illustration 16. The method of any one of the preceding illustrations wherein the stabilizer is comprised of two chemically different stabilizers.

[0084] Illustration 17. The method of any one of the preceding illustrations, wherein the stabilizer is comprised of carboxymethylcellulose stabilizer.

[0085] Illustration 18. The method of any one of the preceding illustrations, wherein the stabilizer is comprised of a surface modified carboxymethylcellulose.

[0086] Illustration 19. The method any one of the preceding illustrations wherein the slurry is deposited upon a metal foil followed by removing the solvent to form a cathode. 19 4894-0899-6840, v.3WCAT-193-B-WO

[0087] Illustration 20. The method of illustration 19, wherein the slurry has one or more additive.

[0088] Illustration 21. The method of illustration 20, wherein the additive is a binder that is comprised of a fluoropolymer or imide.

[0089] Illustration 22. The method of claim 19, wherein the cathode is heated to a carburizing temperature to carburize at least a portion of the stabilizer and the stabilizer is comprised of carboxymethylcellulose.

[0090] Illustration 23. A composite powder comprised of cathode material particles coated with carbon and a stabilizer comprised of carboxymethylcellulose.

[0091] Illustration 24. The composite powder of illustration 23, wherein the carbon is comprised of one or more of carbon black, carbon nanotubes, graphene, graphite, carbon fiber, and acetylene black.

[0092] Illustration 25. The composite powder of illustration 24, wherein the carbon is comprised of the carbon nanotube.

[0093] Illustration 26. The composite powder of illustration 25, wherein the carbon nanotube is comprised of a single wall carbon nanotube.

[0094] Illustration 27. The composite powder of any one of illustrations 22 to 26, wherein the cathode material particles have a specific surface area of 1 m2 / g to 40 m2 / g.

[0095] Illustration 28. The composite powder of any one of illustration 23 to 27, wherein the carbon is present in an amount of 1% to 10% by weight of the cathode material particles, carbon and stabilizer.

[0096] Illustration 29. The composite powder of any one of illustrations 23 to 28, wherein the carbon’s specific surface area is at least 200 m2 / g.

[0097] Illustration 30. The composite powder of any one of illustrations 23 to 29, wherein the carbon / stabilizer weight ratio is 0.2 to 5. 20 4894-0899-6840, v.3WCAT-193-B-WO

[0098] Illustration 31. The composite powder of illustration 30, wherein the carbon / stabilizer weight ratio is 0.5 to 2.

[0099] Illustration 32. The composite powder of any one of illustrations 23 to 31, wherein the stabilizer is comprised of carboxymethylcellulose or salt thereof.

[0100] Illustration 33. The composite powder of illustration 32, wherein the stabilizer is further comprised of a surface modified carboxymethylcellulose.

[0101] Illustration 34. A cathode comprising the composite powder of any one of illustrations 23 to 33.

[0102] Illustration 35. A battery comprising the cathode of illustration 34.

[0103] Illustration 36. A method comprising, (i) milling a slurry comprised of a polar solvent having therein cathode material particles, carbon particles and a stabilizer to a milling energy of 100kWh / t to 700 kWh / t to form a milled mixture and (ii) removing the polar solvent to form a dried mixture comprised of secondary particles of milled cathode material particles coated with milled carbon particles and stabilizer.

[0104] Illustration 37. The method of illustration 36, wherein the cathode material particles have a surface area of 0.1 m2 / g to 1 m2 / g and the carbon particles have a surface area of 50 m2 / g to 400 m2 / g and the carbon particles and stabilizer are present in an amount of 1% to 10% by weight of the cathode material particles, carbon particles and stabilizer.

[0105] Illustration 38. The method of either illustration 36 or 37, wherein the stabilizer is comprised of a carboxymethylcellulose or salt thereof.

[0106] Illustration 39. The method of any one of illustrations 36 to 38, wherein the dried mixture has a surface area of 10 m2 / g to 50 m2 / g.

[0107] Illustration 40. The method of any one of illustrations 36 to 39, wherein the carbon particles are comprised of single wall carbon nanotubes. 21 4894-0899-6840, v.3WCAT-193-B-WO

[0108] Illustration 41. The method of any one of illustration 36 to 40, wherein the cathode material is comprised of one or more of a phosphate, fluorophosphate, fluorosulfate, fluorosilicate, spinel, lithium-rich layered oxide, and composite layered oxide.

[0109] Illustration 42. The method of any one of illustrations 36 to 41, wherein the polar solvent is comprised of water.

[0110] Illustration 43. The method of any one of illustrations 1-22 or 36 to 42, further comprising mixing the secondary particles with a liquid comprised of a polar solvent to form a slurry, depositing the slurry on a metal foil and removing the solvent to form a cathode, wherein the mixing is under agitation insufficient to deagglomerate the secondary particles.

[0111] Illustration 44. The method of illustration 43, wherein the polar solvent is comprised of water.

[0112] Illustration 45. The method of illustration 44, wherein liquid is solely comprised of water.

[0113] Illustration 46. A method to form composite particles comprising mixing a cathode material powder, a particulate carbon and a stabilizer comprised of a carboxymethylcellulose in a liquid, removing the liquid to form coated particles comprised of cathode material particles coated with the stabilizer, heating the coated particles to a carburizing temperature in an atmosphere sufficient to carburize the stabilizer to form composite particles comprised of cathode material particles coated with carbon.

[0114] Illustration 47. The method of illustration 46, wherein the particulate carbon is comprised of graphitic carbon.

[0115] Illustration 48. The method of either illustration 46 or 47, wherein the carbon is comprised of amorphous carbon.

[0116] Illustration 49. The method of any one of illustration 46 to 48, wherein the carburizing temperature is from 200 ℃ to 400 ℃. 22 4894-0899-6840, v.3WCAT-193-B-WO

[0117] Illustration 50. The method of any one of illustration 46 to 49, wherein the amount of carbon is from 1% to 10% by weight of the composite particles. Examples:

[0118] Disordered rocksalt is synthesized via a conventional solid state reaction such as described in U.S. Pat. Publ. No.2022 / 0059816. Typically, stoichiometric amounts of precursors (Mn2O3, TiO2, Nb2O5, Li2CO3 and LiF) were mixed in deionized water to make a suspension (35wt% solids), which is ball milled with a planetary ball mill to decrease the particle size (<300 nm) as well as to obtain a homogeneous mixture of all precursors. The mixture is dried at 100°C for 12h under air before being annealed 12 h at 700C and 20 min at 900C under argon or nitrogen flow (20L / h) to obtain the disordered rocksalt particles having a surface area of about 0.4 m2 / g, which is used herein for each of the examples and comparative examples.

[0119] The appropriate amount of DR and single wall carbon nanotubes having a specific surface area of about 100 m2 / g and stabilizer (2-10 wt%) available under the Tradename TUBALL as a water suspension is wet milled in water with 10 wt% solid content with various milling energies (100 to 500 kWh / T) and bead size of 0.3 mm. The obtained slurry is spray dried (slurry flow rate 3ml / min, temperature 80-90oC, gas flow rate 740 L / h in a Buchi B-290 model mini spray dryer) to obtain carbon / stabilizer coated DR particles with varying primary particle size as reflected by the surface area and average crystallite size (from X-ray line broadening and SEM analysis) as shown in Figures 1 and 2 and 1-5 micrometer secondary particle size as shown in the SEMs of Figures 5 and 6. Figure 3 shows the tap density as a function of the milling energy. Figure 4 shows the X-ray diffractograms of the DR coated particles displaying only the DR phase with no other impurity phases being indicated as well as the line broadening associated with the smaller crystallite size as a function of milling energy.

[0120] The spray dried particles have an average diameter of ~2 micometers and are composed of primary DR nanoparticles coated with carbon particles and stabilzer as shown in scanning electron micrographs of Figures 5 (milled at 200 kWh / t) and 6 (milled at 300 kWh / t). The carbon is uniformly distributed within the secondary particles as observed from energy dispersive X-ray (EDX) elemental mapping. 23 4894-0899-6840, v.3WCAT-193-B-WO

[0121] A summary of the results of the milling the DR particles with carbon nanotubes and CMC stabilizer is shown in Table 1. Table 1: Example Milling SBET Avg Tap Total Carbon* Moisture

[0122] The obtained powder was post annealed at different temperatures such as 150, 250, and 350 ℃ under argon for 12 hours respectively and underwent electrochemical testing and 24 4894-0899-6840, v.3WCAT-193-B-WO washed with water and dried when indicated. The DR carbon / stabilizer coated powder and Comparative Examples are made into battery cells and electrochemical performance evaluated as described below. Comparative Examples 1 and 2 (Control 4 wt% and Control 7 wt% respectively):

[0123] The same DR are particles are dry milled with the same carbon nanotubes in a manner described in U.S. Pat. Pub. US2015-0372299 at a 4% or 7% by weight to form DR carbon coated particles.

[0124] Battery cells of Examples 1-5 are assembled in a high purity argon filled glovebox (M-Braun, O2 and humidity content <0.1ppm) as are the Comparative Examples. The cathode was prepared by mixing the carbon / stabilizer coated disordered rocksalt powder with poly(vinylidene fluoride) (Sigma Aldrich) and 1-methyl-2-pyrrolidone (Sigma Aldrich), and the resulting slurry was deposited on a stainless steel current collector and dried to form a composite powder cathode film. In a like manner the Comparative Examples were made without the stabilizer. For the anode, a thin Li foil was cut into the required size. Each battery cell included a composite cathode film, a polypropylene separator, and a lithium foil anode. An electrolyte (1.0M LiPF6 in EC / EMC (1:2 v / v)) containing lithium hexafluorophosphate in a mixture of ethylene carbonate and ethyl methyl carbonate with an additive was used. The battery cell was sealed and cycled between 1.5-4.6V at 30 ℃ at C / 20 formation rate and C / 3 cycling rate, where 1C = 300 mAh / g. For full cell testing graphite anode has been used and battery has been cycled between 2-4.5 or 2-4.6 V at 30 oC at C / 20 formation rate and C / 3 cycling rate unless otherwise indicated. Comparative Example 3 (CMC stabilizer without any particular carbon):

[0125] Comparative 3 is made in the same manner as Example 3 (500kWh / t milling) except that no particulate carbon is added. The amount of stabilizer is 2g and the amount of carbon formed after annealing at 250C for 12h in Air is about 2-3wt% of carbon.

[0126] Unwashed Examples 1-3 cycle 1 capacity and coulombic efficiency are shown in Figures 7 and 8 that have been heated at differing temperatures after being formed into secondary particles (spray dried). Figures 9 and 10 show the cycling behavior of the same 25 4894-0899-6840, v.3WCAT-193-B-WO battery examples heated to 250 ℃ in air, where it is apparent that Examples 2 and 3 display higher capacity and longer cycle lives compared to Example 1, which may due to the DR of Example 1 not having sufficiently small particle size or coating of carbon and stabilizer (milled less time). The cycle life of Example 2 likewise displays the longest cycle life, which may be due to the size and coating achieved being particularly useful.

[0127] Figures 11 and 12 show the first cycle capacity and coulombic efficiency of Example 4 that has been washed and then heat treated to 250 ℃ versus Comparative Examples 1 and 2. From these results, it is apparent that the method and coated particles of the present invention even though having less carbon and including an electronically insulative compounds (stabilizer) realizes essentially the same first cycle capacity and improved coulombic efficiency. Further Figures 13 and 14 show the cycling behavior of the same examples and comparative examples, where it is readily apparent that the batteries made from the coated DR particles of Example 4 have similar initial capacity and much improved cycle life. Batteries made from the coated DR of Example 5 made in the same manner display similar results as those made from Example 4’s coated DR composite powder.

[0128] The results for a battery made using Comp. Ex.3 cathode material and made in the same manner as described above are shown in Figures 15 and 16, where it is readily apparent that the milling of particulate carbon such as carbon nanotubes without CMC stabilizer results in poor performance (low 1stcharge / discharge capacity). That is, the CMC stabilizer synergistically results in substantial improvements in cycle 1 capacity as is readily apparent from Comp. Ex 3’s results compared to the Examples. It is believed, without being limiting, that the combination of carbon nanotubes, which may be hydrophobic, with the CMC may somehow interact and unexpectedly result in protection of the DR from loss of Li during the milling. 26 4894-0899-6840, v.3

Claims

WCAT-193-B-WO WHAT IS CLAIMED IS:

1. A method comprising, (i) milling a slurry comprised of a polar solvent having therein cathode material particles, carbon particles and a stabilizer to form a milled mixture, the cathode material particle’s specific surface area in m2 / g being at least an order magnitude less than the carbon particles’ specific surface area in m2 / g, and (ii) removing the solvent to form a dried mixture comprised of secondary particles of milled cathode material particles coated with milled carbon particles and stabilizer.

2. The method of claim 1, wherein the stabilizer is comprised of carboxymethylcellulose (CMC).

3. The method of claim 1, wherein the dried mixture has a surface area of at least 1 m2 / g to 40 m2 / g.

4. The method of claim 1, wherein the carbon particles’ specific surface area is at least 20 times greater than the cathode material particles’ specific surface area.

5. The method of claim 1, wherein the carbon particles are comprised of one or more of carbon black, carbon nanotubes, graphene, graphite, carbon fiber, and acetylene black.

6. The method of claim 5, wherein the carbon particles are comprised of single wall carbon nanotubes.

7. The method of claim 5, wherein the carbon particles’ specific surface is at least 50 m2 / g to 200 m2 / g and the cathode materials particles’ specific surface area is from 0.01 m2 / g to 1 m2 / g.

8. The method of claim 1 further comprising one or more of annealing the dried mixture to 200 ℃ to 350 ℃.

9. The method of claim 1, wherein the carbon particles are present in an amount of 1% to 10% by weight of the dried mixture. 27 4894-0899-6840, v.3WCAT-193-B-WO 10. The method of claim 1 wherein the cathode material is comprised of one or more of a phosphate, fluorophosphate, fluorosulfate, fluorosilicate, spinel, lithium-rich layered oxide, and composite layered oxide.

11. The method of claim 1, wherein the milled cathode materials primary particles’ average particle size is at most 500 nm and the milled carbon particles’ average primary particle size is less than the milled cathode material particles’ average primary particle size.

12. The method of claim 1, wherein the removing of the polar solvent is by spray drying.

13. The method of claim 1, wherein the polar solvent is comprised of water having a pH of 7 to 16.

14. The method of claim 8, wherein the dried mixture is annealed from 225 ℃ to 275 °C.

15. The method of claim 14, wherein the annealing is for a time of 1 to 24 hours under non-oxidizing atmosphere.

16. The method of claim 1 wherein the stabilizer is comprised of two chemically different stabilizers.

17. The method of any one of the preceding claims, wherein the stabilizer is comprised of carboxymethylcellulose stabilizer.

18. The method of either claim 17, wherein the stabilizer is comprised of a surface modified carboxymethylcellulose.

19. The method of claim 1, wherein the slurry is deposited upon a metal foil followed by removing the polar solvent to form a cathode.

20. The method of claim 19, wherein the slurry has one or more additive.

21. The method of claim 20, wherein the additive is a binder that is comprised of a fluoropolymer or polyimide. 28 4894-0899-6840, v.3WCAT-193-B-WO 22. The method of claim 19, wherein the cathode is heated to a carburizing temperature to carburize at least a portion of the stabilizer and the stabilizer is comprised of carboxymethylcellulose.

23. A composite powder comprised of cathode material particles coated with carbon and a stabilizer comprised of carboxymethylcellulose.

24. The composite powder of claim 23, wherein the carbon is comprised of one or more of carbon black, carbon nanotubes, graphene, graphite, carbon fiber, and acetylene black.

25. The composite powder of claim 24, wherein the carbon is comprised of the carbon nanotube.

26. The composite powder of claim 25, wherein the carbon nanotube is comprised of a single wall carbon nanotube.

27. The composite powder of claim 23, wherein the cathode material particles have a specific surface area of 1 m2 / g to 40 m2 / g.

28. The composite powder of claim 24, wherein the carbon is present in an amount of 1% to 10% by weight of the cathode material particles, carbon and stabilizer.

29. The composite powder of claim 23, wherein the carbon’s specific surface area is at least 200 m2 / g.

30. The composite powder of claim 23, wherein the carbon / stabilizer weight ratio is 0.2 to 5.

31. The composite powder of claim 30, wherein the carbon / stabilizer weight ratio is 0.5 to 2.

32. The composite powder of any one of claims 23 to 31, wherein the stabilizer is comprised of carboxymethylcellulose or salt thereof.

33. The composite powder of claim 32, wherein the stabilizer is further comprised of a surface modified carboxymethylcellulose. 29 4894-0899-6840, v.3WCAT-193-B-WO 34. A cathode comprising the composite powder of claim 22.

35. A battery comprising the cathode of claim 34.

36. A method comprising, (i) milling a slurry comprised of a polar solvent having therein cathode material particles, carbon particles and a stabilizer to a milling energy of 100kWh / t to 700 kWh / t to form a milled mixture and (ii) removing the polar solvent to form a dried mixture comprised of secondary particles of milled cathode material particles coated with milled carbon particles and stabilizer.

37. The method of claim 36, wherein the cathode material particles have a surface area of 0.1 m2 / g to 1 m2 / g and the carbon particles have a surface area of 50 m2 / g to 400 m2 / g and the carbon particles and stabilizer are present in an amount of 1% to 10% by weight of the cathode material particles, carbon particles and stabilizer.

38. The method of claim 36, wherein the stabilizer is comprised of a carboxymethylcellulose or salt thereof.

39. The method of claim 36, wherein the dried mixture has a surface area of 10 m2 / g to 50 m2 / g.

40. The method of claim 36, wherein the carbon particles are comprised of single wall carbon nanotubes.

41. The method of claim 36, wherein the cathode material is comprised of one or more of a phosphate, fluorophosphate, fluorosulfate, fluorosilicate, spinel, lithium-rich layered oxide, and composite layered oxide.

42. The method of claim 36, wherein the polar solvent is comprised of water.

43. The method of either claim 1 or 36, further comprising mixing the secondary particles with a liquid comprised of a polar solvent to form a slurry, depositing the slurry on a metal foil and removing the solvent to form a cathode, wherein the mixing is under agitation insufficient to deagglomerate the secondary particles. 30 4894-0899-6840, v.3WCAT-193-B-WO 44. The method of claim 43, wherein the polar solvent is comprised of water.

45. The method of claim 44, wherein liquid is solely comprised of water.

46. A method to form composite particles comprising mixing a cathode material powder, a particulate carbon and a stabilizer comprised of a carboxymethylcellulose in a liquid, removing the liquid to form coated particles comprised of cathode material particles coated with the stabilizer, heating the coated particles to a carburizing temperature in an atmosphere sufficient to carburize the stabilizer to form composite particles comprised of cathode material particles coated with carbon.

47. The method of claim 46, wherein the carbon is comprised of amorphous carbon.

48. The method of claim 46, wherein the carburizing temperature is from 200 ℃ to 400 ℃.

49. The method of any one of claim 46 to 48, wherein the carbon is present in an amount from 1% to 10% by weight of the composite particles. 31 4894-0899-6840, v.3

Images