# US 12,603,279 B2 · Positive electrode active material for secondary battery, positive electrode for secondary battery, and secondary battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,603,279 B2 - Document ID: US12603279B2 - Status: Granted - Kind: B2 - Application number: 17/875,978 - Filed: 2022-07-28 - Published: 2022-12-01 - Granted: 2026-04-14 - Earliest claimed: 2020-01-31 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Kazuaki Endoh; Hironobu Kubota - Web page: https://patentgrep.com/patent/US12603279B2 ## CPC - H01M 4/366: {as layered products} - H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx - H01M 4/364: {as mixtures} - H01M 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy - H01M 4/525: of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 2004/021: {Physical characteristics, e.g. porosity, surface area} - H01M 2004/028: {Positive electrodes} - 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 secondary battery includes a positive electrode for a secondary battery, a negative electrode, and an electrolytic solution. The positive electrode for a secondary battery includes a positive electrode active material for a secondary battery. The positive electrode active material for a secondary battery includes first particles and second particles. The first particles have a median diameter D50 of greater than or equal to 15 micrometers and less than or equal to 30 micrometers and each include a lithium-containing compound. The second particles have a median diameter D50 of greater than or equal to 1 micrometer and less than or equal to 10 micrometers and each include a center part that includes a lithium-containing compound and a covering part provided on a surface of the center part. The covering part includes, in order from a side closer to the center part, an underlayer and a surface layer. The underlayer includes a reaction product of a first metal alkoxide in which no alkyl group is bonded to a metal atom. The surface layer includes a reaction product of a second metal alkoxide in which the alkyl group is bonded to the metal atom. The reaction product of the second metal alkoxide is bonded to the reaction product of the first metal alkoxide. ## Claims ### Claim 1 A positive electrode active material for a secondary battery, the positive electrode active material comprising: first particles having a median diameter D50 of greater than or equal to 15 micrometers and less than or equal to 30 micrometers and each including a lithium-containing compound; and second particles having a median diameter D50 of greater than or equal to 1 micrometer and less than or equal to 10 micrometers and each including a center part that includes a lithium-containing compound and a covering part provided on a surface of the center part, wherein the covering part includes, in order from a side closer to the center part, an underlayer including a reaction product of a first metal alkoxide in which an alkyl group is not bonded to a first metal atom, a surface layer including a reaction product of a second metal alkoxide in which the alkyl group is bonded to a second metal atom, the reaction product of the second metal alkoxide being bonded to the reaction product of the first metal alkoxide, and the first metal atom is same as the second metal atom, wherein the first metal atom and the second metal atom are a titanium atom. ### Claim 2 (depends on 1) The positive electrode active material for a secondary battery according to claim 1, wherein the first metal alkoxide includes a compound represented by Formula (4), and the second metal alkoxide includes a compound represented by Formula (5), M11-OR11a (4) where M11 is the first metal atom, R11 is an alkyl group having carbon number of greater than or equal to 1 and less than or equal to 10, and a is a value determined in accordance with a valence of M11, R12-M12-OR13b (5) where M12 is the second metal atom, R12 is an alkyl group having carbon number of greater than or equal to 8 and less than or equal to 30, R13 is an alkyl group having carbon number of greater than or equal to 1 and less than or equal to 10, and b is a value determined in accordance with a valence of M12. ### Claim 3 (depends on 1) The positive electrode active material for a secondary battery according to claim 1, wherein the lithium-containing compound includes at least one of a compound represented by Formula (1), a compound represented by Formula (2), or a compound represented by Formula (3), LiaNi(1-b-c)MnbM1cO(2-d)Xe (1) where M1 is at least one of elements belonging to groups 2 to 15 in a long period periodic table of elements other than Ni and Mn, X is at least one of elements belonging to groups 16 and 17 in the long period periodic table of elements other than O, and a, b, c, d, and e satisfy 0≤a≤1.5, 0≤b≤1, 0≤c≤1, −0.1≤d≤0.2, and 0≤e≤0.2, LiaCo(1-b)M2bO(2-c) (2) where M2 is at least one of V, Cu, Zr, Zn, Mg, Al, Ga, Y, or Fe, and a, b, and c satisfy 0.9≤a≤1.1, 0≤b≤0.3, and −0.1≤c≤0.1, LiaNibCocMndM3(1-b-c-d)O(2-e) (3) where M3 is at least one of V, Cu, Zr, Zn, Mg, Al, Ga, Y, or Fe, and a, b, c, d, and e satisfy −0.1≤a≤0.1, 0.9≤b≤1.1, 0