| abstract |
Lithium-nickel-manganese-cobalt composite oxide used as a positive electrode active material for a Li secondary battery has low battery performance, particularly discharge capacity and discharge capacity maintenance ratio, even when the packing density (press density) increases. There is provided a lithium-nickel-manganese-cobalt composite compound. A lithium-nickel-manganese-cobalt composite oxide having a press density of 3.3 to 4.5 g / cm 3 and a ratio of particles of 10 μm or less in a volume-based particle size distribution of 10 to 70% by volume. Is used as the positive electrode material. The lithium-nickel-manganese-cobalt composite oxide preferably has a BET specific surface area represented by the following chemical formula of 0.05 to 1.0 m 2 / g. Li 1 + a Ni b Mn c Co d Me O 2 (M is a metal other than Ni, Mn, Co and Li) a + b + c + d + e = 1 0 <a ≦ 0.2 0.2 ≦ b / (b + c + d) ≦ 0.4 0 .2 ≦ c / (b + c + d) ≦ 0.4 0 <d / (b + c + d) ≦ 0.4 0 ≦ e ≦ 0.1 [Selection figure] None |