Patent ID: 7556889

Claim:
A positive electrode active material for a secondary battery comprising a lithium manganate and a lithium nickelate, wherein said lithium manganate is a particle compound having a spinel structure represented by the following formula (1) or said compound in which some of Mn or O sites are replaced with another element; and an Mn elution amount when immersing said particles in a mixture comprising an electrolyte salt and a carbonate solvent is 1000 ppm or less as determined by inductive coupling plasma emission analysis; and a specific surface area of said particles as determined by the BET method is 0.3 m 2 / g to 0.8 m 2 /g both inclusive: Li 1+x Mn 2−x O 4 (1) (in said formula (1) above, 0.15 x 0.24).