| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material, usable even under a high voltage, excellent in battery performance such as discharge capacity, discharge average voltage, stability, volume capacity density, and charge/discharge cycle durability.SOLUTION: The positive electrode active material for a lithium ion secondary battery has phosphate on particle surfaces of a complex oxide containing lithium cobalt. A ratio D2/D1 of a phosphate crystallite diameter D2 to a lithium cobalt-containing complex oxide crystallite diameter D1 satisfies D2/D1≥0.45. |
