Patent ID: 8187747

Claim:
A method for producing a positive electrode active material for a non-aqueous electrolyte-based secondary battery, comprising a lithium/nickel composite oxide, characterized by including the following steps (a) to (c): (a) A nickel oxide containing nickel, as a main component, and at least one kind of an element selected from a group of Co, Al, Mg, and Mn, as a side component is prepared by roasting nickel hydroxide or nickel oxyhydroxide containing nickel, as a main component, and at least one kind of an element selected from a group of Co, Al, Mg, and Mn, as a side component, at a temperature of 600 to 1100° C. under air atmosphere; (b) Fired powders represented by the following composition formula (1) are prepared by mixing the nickel oxide and a lithium compound, and then firing at a maximal temperature range of 650 to 850° C. under oxygen atmosphere: LiNi 1-a M a O 2 (1) (wherein, M represents at least one kind of an element selected from a group of Co, Al, Mg, and Mn; and “a” satisfies 0.01 <a <0.5); (c) The fired powders are washed with water desirably within a time satisfying the following equation (2) and then filtered and dried: A ≦B/ 40 (2) (wherein, A represents water washing time represented by unit of minute; and B represents slurry concentration represented by unit of g/L).