POSITIVE ELECTRODE ACTIVE MATERIAL FOR NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD FOR PRODUCING THE SAME

A positive electrode active material for a non-aqueous electrolyte secondary battery that includes a lithium transition metal composite oxide having a spinel structure and containing nickel and manganese is provided. The positive electrode active material includes a first surface region having a chemical composition with a molar ratio of nickel to manganese of 0.1 or less on the surface of the lithium transition metal composite oxide.