| abstract |
The object of the present invention is to provide a positive electrode active material usable for a lithium ion battery capable of high charge/discharge cycle performance and high discharge capacity. The positive electrode active material for a lithium secondary battery has a layered structure and comprises at least nickel, cobalt and manganese. Further, the positive electrode active material satisfies requirements (1) to (3) below: (1) a primary particle size of 0.1 μm to 1 μm, and a 50% cumulative particle size D 50 of 1 μm to 10 μm, (2) a ratio (D 90 /D 10 ) of volume-based 90% cumulative particle size D 50 to volume-based 10% cumulative particle size D 10 of 2 to 6, and (3) a lithium carbonate content in a residual alkali on particle surfaces of 0.1% by mass to 0.8% by mass as measured by neutralization titration. |