POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

A positive electrode active material for nonaqueous electrolyte secondary batteries which allows the capacity of nonaqueous electrolyte secondary batteries to be increased and offers a smaller decrease in charge discharge cycle characteristics, and to provide a nonaqueous electrolyte secondary battery having such a positive electrode active material. A positive electrode active material for nonaqueous electrolyte secondary batteries according to the present invention includes a composite oxide containing Li, Ni, Co, Al, W and additive elements M, the proportion of Ni in the composite oxide being not less than 80 mol % relative to the total number of moles of the metal elements except Li, the additive elements M including at least either of an alkaline earth metal element and an alkali metal element except Li, and a tetravalent or higher valent element, the average valence of the additive elements M being not less than 3.6.