POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES, METHOD FOR PRODUCING SAME AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY USING SAID POSITIVE ELECTRODE ACTIVE MATERIAL

Provided is a positive electrode active material that has high output characteristics and battery capacity when used for a positive electrode of a nonaqueous electrolyte secondary battery and can inhibit gelation of positive electrode mixture paste. A method for producing the positive electrode active material is also provided. A positive electrode active material for a nonaqueous electrolyte secondary battery contains a lithium-nickel-cobalt-manganese composite oxide represented by General Formula (1): LiNiCoMnBM1O and having a hexagonal layered crystal structure. The lithium-nickel-cobalt-manganese composite oxide contains a secondary particle formed of a plurality of flocculated primary particles and a boron compound containing lithium present at least on part of surfaces of the primary particles. A water-soluble Li amount present on the surfaces of the primary particles is up to 0.1% by mass relative to the entire amount of the positive electrode active material.