Patent ID: 8801960

Claim:
A method for producing a lithium-containing complex oxide, comprising: coprecipitating a complex compound containing at least Ni and Mn as constituent elements in an inactive atmosphere; mixing the complex compound and a compound of Li at a predetermined ratio; and sintering the mixture at a sintering temperature of about 700° C. to 1100° C. in an atmosphere containing oxygen, thereby forming a complex oxide with a layered crystal structure, wherein the lithium-containing complex oxide further contains a substituent element M, wherein the substituent element M contains Co, and assuming that a total quantity of Ni, Mn, and the substituent element M is 1-x, and a quantity ratio of the substituent element M is y, x satisfies 0≦x≦0.05, y satisfies 0.1<y≦0.4, and a quantity ratio of Co is 0.1 or more, wherein a composition of the complex compound containing at least Ni and Mn as constituent elements is adjusted so that a difference δ in a quantity ratio between Ni and Mn constituting the lithium-containing complex oxide satisfies −0.1≦δ≦0.1, and wherein an average valence of Mn constituting the lithium-containing complex oxide is set to be about 3.3 to 4.