Active material for non-aqueous electrolyte secondary battery, method for production of the active material, electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery

There is provided an active material for a nonaqueous electrolyte secondary battery, including a lithium-transition metal composite oxide which has an ±-NaFeO 2 -type crystal structure and of which the average composition is represented by the composition formula of Li 1+± Me 1-± O 2 (Me is a transition metal containing Co, Ni and Mn; and ± > 0), wherein the lithium-transition metal composite oxide is a particle having a core and a coated part, the cobalt concentration of the coated part is higher than the cobalt concentration of the core, the manganese concentration of the coated part is lower than the manganese concentration of the core, and the ratio of cobalt present in the coated part is 3 to 10% in terms of a molar ratio based on the amount of the transition metal present in the core.