NICKEL COMPOSITE HYDROXIDE PARTICLE AND PROCESS FOR PRODUCING THE SAME, POSITIVE ELECTRODE ACTIVE MATERIAL FOR NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND PROCESS FOR PRODUCING THE SAME, AND NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

An objective of the present invention is to provide a non-aqueous electrolyte secondary battery positive electrode active material formed from a lithium-nickel composite oxide which, while retaining high capacity and a high level of safety, has an excellent cycle characteristic by controlling reaction resistance and a method for producing it. [Solution] A lithium-nickel composite oxide is produced by steps (a) to (c) described below: (a) nickel hydroxide and/or nickel oxyhydroxide in a prescribed composition are sintered in a non-reducing atmosphere having 850° C. or lower to give nickel oxide; (b) after the nickel oxide and a lithium compound are mixed in a prescribed molar ratio, the mixture is sintered in an oxygen atmosphere at a temperature of 650 to 850° C.; and (c) after an obtained powder is made to be in a prescribed slurry concentration, it is washed with water during a period of time which satisfies the following formula: B/40