| 摘要 |
Provided is a novel lithium composite metal oxide having excellent Li storage capacity even when used in a secondary battery driven by high voltage, i.e., used as an active material having excellent capacity retention. A lithium composite metal oxide represented by the general formula: LiaNibCocMndDeOf (0.2 ≦ a ≦ 1.5, b + c + d + e = 1, 0 < e < 1, D is at least one element selected from Fe, Cr, Cu, Zn, Ca, Mg, Zr, S, Si, Na, K, Al, Ti, P, Ga, Ge, V, Mo, Nb, W, La, Hf, and Rf, and 1.7 ≦ f ≦ 2.1), wherein the lithium composite metal oxide is characterized in having a high-manganese component that is a metal oxide containing at least Ni, Co, and Mn, the high-manganese component being represented by a compositional ratio of Ni, Co, and Mn of Ni:Co:Mn=g:h:i (where g + h + i = 1, 0 < g < 1, 0 < h < c, and d < i < 1), in the surface layer, and having a metal oxide component in the outermost layer of this high-manganese component. |
