SPINEL TYPE LITHIUM NICKEL MANGANESE-CONTAINING COMPOSITE OXIDE

Disclosed is a 5 V class spinel type lithium nickel manganese-containing composite oxide having an operating potential of 4.5 V or more with respect to a metal Li reference potential, wherein the composite oxide is able to improve cycle characteristics while suppressing the amount of gas generated under high temperature environments and, moreover, to improve output characteristics while suppressing a shoulder on discharge at around 4.1 V in a charge and discharge curve.Proposed is a spinel type lithium nickel manganese-containing composite oxide represented by a general formula [Li(LiaNiyMnxTibMgzMα)Oz-δ] (where 0 < a, 0 < b, 0.30 ≤ y < 0.60, 0 < z, 0 ≤ α, x = 2-a-b-y-z-α < 1.7, 3 ≤ b/a ≤ 8, 0.11 < b+z+α, 0 < z/b ≤ 1, 0 ≤ δ ≤ 0.2, and M represents one or two or more elements selected from the group consisting of Fe, Co, Ba, Cr, W, Mo, Y, Zr, Nb, P, and Ce).