| abstract |
A positive electrode active material for lithium-ion secondary batteries having excellent cycle and rate characteristics, even when charged at a high voltage, is provided. The positive electrode material for lithium-ion secondary batteries: comprises particles (III) having a covering layer containing a metal oxide (I), which contains at least one type of metal element selected from a group comprising Al, Y, Ga, In, La, Pr, Nd, Gd, Dy, Er and Yb, and a compound (II), which contains at least one type of non-metal element selected from a group comprising Li, S and B, on the surface of a lithium-containing complex oxide; and is characterized in that the atomic ratio (the non-metal element/the metal element) within 5 nm of the surface layer of the particles (III) lies in a specific range. |