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

A positive electrode active material for a non-aqueous electrolyte secondary battery according to one embodiment comprises a lithium transition metal composite oxide represented by the compositional formula LiNaNiMnXO(where X is at least one element selected from metallic elements other than Li, Na, Ni, and Mn, 0.80≤α≤1.20, 0≤β≤0.05, 0.80≤α+β≤1.20, 0.25