# US 8,771,876 B2 · Positive electrode active material, method for manufacturing positive electrode active material and nonaqueous electrolyte battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,876 B2 - Document ID: US8771876B2 - Status: Granted - Kind: B2 - Application number: 12/761,172 - Filed: 2010-04-15 - Published: 2010-10-28 - Granted: 2014-07-08 - Earliest claimed: 2009-04-22 - Assignees: Sony Corporation - Applicants: Haruo Watanabe; Tomoyo Ooyama; Yosuke Hosoya; Shigeru Fujita - Inventors: Haruo Watanabe; Tomoyo Ooyama; Yosuke Hosoya; Shigeru Fujita - Web page: https://patentgrep.com/patent/US8771876B2 ## CPC - H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx - 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} - H01M 4/485: of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) - 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 4/02: Electrodes composed of, or comprising, active material - H01M 4/587: for inserting or intercalating light metals - 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 positive electrode active material includes a lithium complex oxide particle, and a coating layer formed on at least a part of the surface of the lithium complex oxide particle. The lithium complex oxide particle is a lithium complex oxide particle composed mainly of nickel. The coating layer contains an oxo acid and/or an oxo acid compound, an acidity of the surface of the lithium complex oxide particle composed mainly of nickel is increased by the coating layer. The acidity is determined based on a pH of a supernatant of water in a state where after 1.0 part by weight of the lithium complex oxide particle composed mainly of nickel and having a coating layer formed thereon is dispersed in 50 parts by weight of water. The lithium complex oxide particle sediments, and the pH is less than 8.0. ## Claims ### Claim 1 A positive electrode active material comprising: a lithium complex oxide particle; and a coating layer formed on at least a part of a surface of the lithium complex oxide particle, wherein the lithium complex oxide particle is composed mainly of nickel, the coating layer contains an oxo acid and/or an oxo acid compound, an acidity of the surface of the lithium complex oxide particle is increased by the coating layer, the acidity is determined based on a pH of a supernatant of water in a state where after 1.0 part by weight of the lithium complex oxide particle and having a coating layer formed thereon is dispersed in 50 parts by weight of water, the lithium complex oxide particle sediments, and the pH is less than 8.0. ### Claim 2 (depends on 1) The positive electrode active material according to claim 1, wherein a discharge capacity of the lithium complex oxide particle is lowered by the formation of the coating layer by less than 5% relative to the discharge capacity of the lithium complex oxide particle prior to the formation of the coating layer. ### Claim 3 (depends on 1) The positive electrode active material according to claim 1, wherein the lithium complex oxide particle has an average composition represented by the following formula (1) LiaNixCoyAlzO2 (1) wherein nickel is able to be substituted with one or two or more kinds of metal elements selected from the group consisting of manganese, chromium, iron, vanadium, magnesium, titanium, zirconium, niobium, molybdenum, tungsten, copper, zinc, gallium, indium, tin, lanthanum and cerium within the range of not more than 0.1 of Ni when the amount of the whole of Ni is defined to be 1; a, x, y and z are values falling within the ranges of (0.20≦a≦1.40), (0.60