# US 9,437,863 B2 · Surface coating method and a method for reducing irreversible capacity loss of a lithium rich transitional oxide electrode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,863 B2 - Document ID: US9437863B2 - Status: Granted - Kind: B2 - Application number: 13/785,783 - Filed: 2013-03-05 - Published: 2014-09-11 - Granted: 2016-09-06 - Earliest claimed: 2013-03-05 - Assignees: GM Global Technologies Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Qiangfeng Xiao; Mei Cai - Web page: https://patentgrep.com/patent/US9437863B2 ## CPC - H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis} - H01M 4/1391: of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx - H01M 4/366: {as layered products} - Y02E 60/10: Energy storage using batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A surface coating method and a method for reducing irreversible capacity loss of a lithium rich transitional oxide electrode are disclosed herein. In an example of the surface coating method, a dispersion of a lithium rich transitional oxide powder and an oxide precursor or a phosphate precursor in a liquid is formed. The liquid is evaporated. The forming and evaporating steps are carried out in the absence of air to prevent precipitation of the oxide precursor or the phosphate precursor. Hydrolyzation of the oxide precursor or the phosphate precursor is controlled under predetermined conditions, and an intermediate product is formed. The intermediate product is annealed to form an oxide coated lithium rich transitional oxide powder or the phosphate coated lithium rich transitional oxide powder. ## Claims ### Claim 1 A surface coating method, comprising: forming a dispersion of a lithium rich transitional oxide powder and an oxide precursor or a phosphate precursor in a liquid; evaporating the liquid; carrying out the forming and the evaporating steps in the absence of air to prevent precipitation of the oxide precursor or the phosphate precursor; controlling hydrolyzation of the oxide precursor or the phosphate precursor under predetermined conditions, thereby forming an intermediate product; and annealing the intermediate product to form an oxide coated lithium rich transitional oxide powder or a phosphate coated lithium rich transitional oxide powder. ### Claim 2 (depends on 1) The surface coating method as defined in claim 1 wherein the lithium rich transitional oxide powder is xLi2MnO3-(1−x)LiMO2, where 0≦x≦1, and M=Ni, Co or Mn. ### Claim 3 (depends on 1) The surface coating method as defined in claim 1 wherein: the oxide precursor is selected from the group consisting of a vanadium oxide precursor, a titanium oxide precursor, a zirconium oxide precursor, an aluminum oxide precursor, a zinc oxide precursor, a niobium oxide precursor, a tungsten oxide precursor, and a silicon dioxide precursor; or the phosphate precursor is selected from the group consisting of an aluminum phosphate precursor, a cobalt phosphate precursor, and a titanium phosphate precursor. ### Claim 4 (depends on 3) The surface coating method as defined in claim 3 wherein the oxide precursor is triisopropoxyvanadium(V) oxide. ### Claim 5 (depends on 4) The surface coating method as defined in claim 4 wherein annealing is accomplished at a temperature ranging from about 100° C. to about 300° C. ### Claim 6 (depends on 3) The surface coating method as defined in claim 3 wherein: the titanium oxide precursor is used, and annealing is accomplished at a temperature ranging from about 100° C. to about 400° C.; the zirconium oxide precursor is used, and annealing is accomplished at a temperature ranging from about 100° C. to about 400° C.; the aluminum oxide precursor is used, and annealing is accomplished at a temperature ranging from about 100° C. to about 350° C.; the zinc oxide precursor is used, and annealing is accomplished at a temperature of less than 90° C.; the niobium oxide precursor is used, and annealing is accomplished at a temperature ranging from about 100° C. to about 700° C.; the tungsten oxide precursor is used, and annealing is accomplished at a temperature ranging from about 100° C. to about 200° C.; or the silicon dioxide precursor is used, and annealing is accomplished at a temperature ranging from about 100° C. to about 500° C. ### Claim 7 (depends on 3) The surface coating method as defined in claim 3 wherein: the aluminum phosphate precursor is used, and annealing is accomplished at a temperature of about 400° C.; or the cobalt phosphate precursor is used, and annealing is accomplished at a temperature of about 400° C. ### Claim 8 (depends on 1) The surface coating method as defined in claim 1 wherein controlling hydrolyzation is accomplished by exposing the lithium rich transitional oxide powder and the oxide precursor or the phosphate precursor to water vapor, and wherein the predetermined conditions include: an air-free sealed environment; and a temperature ranging from about 50° C. to about 80° C. ### Claim 9 (depends on 1) The surface coating method as defined in claim 1 wherein forming the dispersion includes: adding the lithium rich transitional oxide powder to the liquid to form an initial dispersion; and adding the oxide precursor or the phosphate precursor to the initial dispersion. ### Claim 10 (depends on 1) The surface coating method as defined in claim 1 wherein a weight ratio of oxide coating or phosphate coating to the lithium rich transitional oxide powder ranges from about 10:100 to about 20:100. ### Claim 11 (depends on 1) The surface coating method as defined in claim 1 wherein carrying out the forming and the evaporating steps in the absence of air is accomplished by performing the forming and the evaporating steps in a glove box in the presence of argon gas. ### Claim 12 A method for reducing irreversible capacity loss of a lithium rich transitional oxide electrode, the method comprising: forming a dispersion of a lithium rich transitional oxide powder in a liquid; adding an oxide precursor to the dispersion; evaporating the liquid from the dispersion; carrying out the forming, the adding, and the evaporating steps in the absence of air to prevent precipitation of the oxide precursor; hydrolyzing the oxide precursor in an air-free sealed environment using water vapor at a predetermined temperature, thereby forming an intermediate product; annealing the intermediate product, thereby forming an oxide coated lithium rich transitional oxide powder; and using the oxide coated lithium rich transitional oxide powder to form the lithium rich transitional oxide electrode. ### Claim 13 (depends on 12) The method as defined in claim 12 wherein using the oxide coated lithium rich transitional oxide powder to form the lithium rich transitional oxide electrode includes: mixing the oxide coated lithium rich transitional oxide powder with a conductive carbon black material and a binder to form a mixture; forming a slurry of the mixture; spreading the slurry into a sheet form; and punching and drying the sheet form to generate the lithium rich transitional oxide electrode. ### Claim 14 (depends on 13) The method as defined in claim 13 wherein a ratio of the oxide coated lithium rich transitional oxide powder to the conductive carbon black material to the binder is 75:25:5. ### Claim 15 (depends on 12) The method as defined in claim 12 wherein: the lithium rich transitional oxide powder is xLi2MnO3-(1−x)LiMO2, where 0≦x≦1, and M=Ni, Co or Mn; the liquid is tetrahydrofuran; and the oxide precursor is selected from the group consisting of a vanadium oxide precursor, a titanium oxide precursor, a zirconium oxide precursor, an aluminum oxide precursor, a zinc oxide precursor, a niobium oxide precursor, a tungsten oxide precursor, a silicon dioxide precursor, and combinations thereof. ### Claim 16 (depends on 12) The method as defined in claim 12 wherein the predetermined temperature ranges from about 50° C. to about 80° C. ### Claim 17 (depends on 12) The method as defined in claim 12 wherein a weight ratio of oxide coating to the lithium rich transitional oxide powder ranges from about 10:100 to about 20:100. ### Claim 18 (depends on 12) The method as defined in claim 12 wherein carrying out the forming, the adding, and the evaporating steps in the absence of air is accomplished by performing the forming, the adding, and the evaporating steps in a glove box in the presence of argon gas. ### Claim 19 A method for reducing irreversible capacity loss of a lithium rich transitional oxide electrode, the method comprising: forming a dispersion of a lithium rich transitional oxide powder in tetrahydrofuran; adding triisopropoxyvanadium(V) oxide to the dispersion; evaporating the tetrahydrofuran from the dispersion; carrying out the forming, the adding, and the evaporating steps in the absence of air to prevent precipitation of the triisopropoxyvanadium(V) oxide; hydrolyzing the triisopropoxyvanadium(V) oxide in an air-free sealed environment using water vapor and a temperature ranging from about 50° C. to about 80° C., thereby forming an intermediate product; annealing the intermediate product, thereby forming a vanadium oxide coated lithium rich transitional oxide powder; and using the vanadium oxide coated lithium rich transitional oxide powder to form the lithium rich transitional oxide electrode. ### Claim 20 (depends on 19) The method as defined in claim 19 wherein using the vanadium oxide coated lithium rich transitional oxide powder to form the lithium rich transitional oxide electrode includes: mixing the vanadium oxide coated lithium rich transitional oxide powder with a conductive carbon black material and a polytetrafluoroethylene (PTFE) binder to form a mixture; adding isopropanol to form a slurry of the mixture; spreading the slurry into a sheet form; and punching and drying the sheet form to generate the lithium rich transitional oxide electrode.