| 摘要 |
A positive electrode active material includes composite oxide particles containing cobalt as a constituent metal, element. The composite oxide particles have a cobalt concentration which is higher in surface portions than in central portions of the composite oxide particles. In a particle size distribution of the composite oxide particles, a value of a ratio D10/D50 of a diameter D10 corresponding to 10% of a cumulative particle volume counted from a small particle diameter side in a particle size distribution of the composite oxide particles to a diameter D50 corresponding to 50% of the cumulative particle volume counted satisfies D10/D50≤0.75. |
