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

This positive electrode active material used in a non-aqueous electrolyte secondary battery includes a lithium transition metal composite oxide containing Al and Ni in an amount of at least 80 mol% with respect to the total number of moles of metal elements excluding Li, wherein a primary particle of the lithium transition metal composite oxide has a surface modification layer containing at least Ca on the surface thereof.