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

1 . A lithium metal composite oxide powder, comprising:

secondary particles that are aggregates of primary particles, and

single particles that are present independently of the secondary particles,

wherein the lithium metal composite oxide is represented by composition formula (I), and a relationship [a/(a+b)] satisfies 0.5<[a/(a+b)]<1.0 when a number of the single particles is a and a number of the secondary particles is b:

Li[Li x (Ni (1-y-z-w) Co y Mn z Mn w ) 1-x ]O 2   (I)

wherein M is one or more metal elements selected from the group consisting of Fe, Cu, Ti, Mg, Al, W, B, Mo, Nb, Zn, Sn, Zr, Ga, La, and V, −0.1≤x≤0.2, 0≤y≤0.4, 0≤z≤0.4, and 0≤w≤0.1.

2 . The lithium metal composite oxide powder according to claim 1 , wherein in the composition formula (I), 0<x≤0.2.

3 . The lithium metal composite oxide powder according to claim 1 , wherein the relationship [a/(a+b)] satisfies 0.8<[a/(a+b)]<1.0.

4 . The lithium metal composite oxide powder according to claim 1 , wherein an average particle diameter of the single particles is 0.5 μm or more and 7 μm or less.

5 . The lithium metal composite oxide powder according to claim 1 , wherein an average particle diameter of the secondary particles is 2 μm or more and 20 μm or less.

6 . A positive electrode active material for a lithium secondary battery, comprising the lithium metal composite oxide powder according to claim 1 .

7 . A positive electrode comprising the positive electrode active material of claim 6 .

8 . A lithium secondary battery comprising the positive electrode of claim 7 .