LITHIUM METAL COMPOSITE OXIDE POWDER AND POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY

A lithium metal composite oxide powder having a layered structure, containing at least Li, Ni, an element X, and an element M, in which the element X is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, and V, the element M is one or more elements selected from the group consisting of B, Si, S, and P, M/(Ni+X) that is a content ratio of the element M to a total amount of Ni and the element X that are contained in the lithium metal composite oxide powder is 0.01 mol % or more and 5 mol % or less, Ni/(Ni+X) that is a content ratio of Ni to the total amount of Ni and the element X that are contained in the lithium metal composite oxide powder satisfies 0.40 or more in terms of a mole ratio, and a ratio of the element M eluted into N-methyl-2-pyrrolidone measured under specific measurement conditions is 0.09 or less.