| 摘要 |
To provide a cathode active material for a lithium ion secondary battery excellent in the cycle characteristics and rate characteristics even when charging is conducted at a high voltage. A cathode active material for a lithium ion secondary battery, which comprises particles (III) having a covering layer comprising a metal oxide (I) containing at least one metal element selected from the group consisting of elements in Groups 3 and 13 of the periodic table and lanthanoid elements, and a compound (II) containing Li and P, on the surface of a lithium-containing composite oxide comprising lithium and a transition metal element, wherein the atomic ratio of said P to said metal element (P/metal element) contained within 5 nm of the surface layer of the particles (III) is from 0.03 to 0.45. |
