| 摘要 |
Provided are a positive electrode active material for a lithium ion secondary battery and a secondary battery using the same, by which high discharge energy is obtained at low cost and capacity drop with cycles can be suppressed. A positive electrode active material for a secondary battery according to the embodiment of the present invention is represented by the following formula (I): Lia(FexNiyMn2-x-y-zAz)O4  (I) wherein 0.2<x≦̸1.2, 0<y<0.5, 0≦̸a≦̸1.2 and 0<z≦̸0.3; A is at least one selected from the group consisting of Li, B, Na, Mg, Al, K and Ca. |
