| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material for a lithium ion secondary battery, which has a low resistance, a high capacity, and superior charge and discharge cycle characteristics.SOLUTION: A positive electrode active material for a lithium ion secondary battery comprises: primary particles of a material expressed by the compositional formula (1), LiNiCoMO(1) [where x is a number satisfying -0.12≤x≤0.2; y is a number satisfying 0.7≤y≤0.9; z is a number satisfying 0.05≤z≤0.3; and M represents at least one element selected from a group consisting of Mg, Al, Ti, Mn, Zr, Mo and Nb]; or secondary particles each composed of an agglomerate of the primary particles. The primary particles or the secondary particles include a free lithium compound at a percentage of 0.1-2.0% by weight. The weight of lithium hydroxide in the free lithium compound is 60% or less of the weight of lithium carbonate in the free lithium compound.SELECTED DRAWING: Figure 1 |
