Lithium composite metal oxide, positive electrode active substance, positive electrode, and non-aqueous electrolyte secondary battery

1. A lithium composite metal oxide which

contains Li, Ni, and Mn,

has a lamellar structure,

has a diffraction peak in a range of 2θ=20.8±1° in a powder X-ray diffraction pattern obtained through powder X-ray diffraction measurement using a Cu—Kα radiation,

has a BET specific surface area of from 6 m 2 /g to 30 m 2 /g, and

has an average particle diameter measured by a laser diffraction scattering method of from 0.1 μm to 10 μm, and

wherein the lithium composite metal oxide is represented by Formula (B) described below

n Li 2b/3 MnO 3 .(1 −n )Li b/3 Ni 1-p-q Mn p M q O 2   (B),

wherein in Formula (B) 0.2≦n≦0.6, 2.75≦b<3.0, 0.25≦p≦0.5, 0≦q≦0.31, 0.38≦p+q≦0.5, and M represents one or more elements selected from the group consisting of Co, Fe, Mg, Al, and Ca.

2. The lithium composite metal oxide according to claim 1 ,

wherein an average primary particle diameter of the lithium composite metal oxide is from 0.05 μm to 0.3 μm.

3. The lithium composite metal oxide according to claim 1 ,

wherein M represents one or more elements selected from the group consisting of Co and Fe.

4. A positive electrode active material comprising:

the lithium composite metal oxide according to claim 1 .

5. A positive electrode comprising:

the positive electrode active substance according to claim 4 .

6. A non-aqueous electrolyte secondary battery comprising:

a negative electrode and the positive electrode according to claim 5 .

7. The non-aqueous electrolyte secondary battery according to claim 6 ,

wherein a charge potential of the positive electrode in a fully charged state is 4.35 V (vs. Li/Li + ) or more.