▎ 摘　　要

NOVELTY - Positive electrode active material comprises a granule composed of olivine-type phosphate particles containing manganese and graphene particles having a phosphate group. USE - The positive electrode active material is used in a lithium ion secondary battery (claimed). ADVANTAGE - The positive electrode active material has a high discharge potential and excellent cycle resistance in high rate conditions, and provides lithium-ion secondary batteries with high energy density, excellent output characteristics and improved safety. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for producing the positive electrode active material, comprising (1) mixing and pulverizing olivine-type phosphate particles containing manganese and a dispersion medium to prepare a dispersion, (2) mixing the dispersion obtained in step (1) and graphene particles having a phosphate group to prepare a mixed dispersion of olivine-type phosphate particles containing manganese and graphene particles having a phosphate group, (3) spray drying the dispersion obtained in step (2) to obtain granules containing olivine-type phosphate particles containing manganese and graphene particles having a phosphate group, and (4) calcining the granules obtained in step (3) at a temperature of 400-1000° C in a reducing atmosphere or an inert atmosphere.