| abstract |
Disclosed is a positive electrode active material for a lithium ion secondary battery that can suppress gas generation and can provide a lithium ion secondary battery having a high capacity retention rate in a charge / discharge cycle. The positive electrode active material for a lithium ion secondary battery according to the present embodiment has a layered rock salt structure, and Li x Fe s M 1 (z−s) M 2 y O δ (1.05 ≦ x ≦ 1. 90, 0.05 ≦ s ≦ 0.50, 0.05 ≦ z ≦ 0.50, 0.33 ≦ y ≦ 0.90, 1.20 ≦ δ ≦ 3.10, z−s ≧ 0, M 1 is at least one element selected from the group consisting of Co and Ni, and M 2 is at least one element selected from the group consisting of Mn, Ti and Zr.) And specific 1,3-propanedione derivatives. |