Lithium composite metal oxide, positive electrode active material for lithium secondary batteries, positive electrode for lithium secondary batteries, and lithium secondary battery
The present invention relates to a lithium composite metal oxide which satisfies the requirements (1) and (2) described below. Requirement (1): The ratio of the half width A of the diffraction peak within the range of 2θ=64.5±1° to the half width B of the diffraction peak within the range of 2θ=44.4±1°, namely A/B is from 1.39 to 1.75 (inclusive) in powder X-ray diffractometry using a Cu—Kα ray. Requirement (2): The ratio of the volume-based 90% cumulative particle size (D 90 ) to the volume-based 10% cumulative particle size (D 10 ), namely D 90 /D 10 is 3 or more.
1. A lithium composite metal oxide which satisfies requirements (1) and (2):
(1) a ratio (AB) of a half width A of a diffraction peak in a range of 2θ=64.5±1° with respect to a half width B of a diffraction peak in a range of 2θ=44.4±1° in a powder X-ray diffraction measurement for the lithium composite metal oxide using Cu—Kα ray is 1.43 or more and 1.75 or less;
(2) a ratio (D 90 /D 10 ) of a volume-based 90% cumulative particle size (D 90 ) determined from a particle size distribution measurement with respect to a volume-based 10% cumulative particle size (D 10 ) determined from the particle size distribution measurement is 3 or more.
2. The lithium composite metal oxide according to claim 1 , which satisfies requirement (1)-1: the half width A is 0.200° or more and 0.350° or less.
3. The lithium composite metal oxide according to claim 2 , which satisfies requirement (3): a ratio I 2 /I 1 of an integral intensity I 2 of a diffraction peak in a range of 2θ=18.5±1° with respect to an integral intensity I 1 of a diffraction peak in a range of 2θ=64.5±1° in a powder X-ray diffraction measurement for the lithium composite metal oxide using Cu—Kα ray is 4.0 or more and 6.0 or less.
4. The lithium composite metal oxide according to claim 1 , which satisfies requirement (3): a ratio I 2 /I 1 of an integral intensity I 2 of a diffraction peak in a range of 2θ=18.5±1° with respect to an integral intensity I 1 of a diffraction peak in a range of 2θ=64.5±1° in a powder X-ray diffraction measurement for the lithium composite metal oxide using Cu—Kα ray is 4.0 or more and 6.0 or less.
5. The lithium composite metal oxide according to claim 1 , which satisfies composition formula (I):
Li[Li x (Ni (1-y-z-w) Co y Mn z M w ) 1-x ]O 2 (I),
wherein relations −0.1≤x≤0.2, 0≤y≤0.4, 0≤z≤0.4, 0≤w≤0.1, and y+z+w<1 are satisfied, and M is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, Zn, B, Al, Ga, Ti, Zr, Ge, Fe, Cu, Cr, V, W, Mo, Sc, Y, Nb, La, Ta, Tc, Ru, Rh, Pd, Ag, Cd, In, and Sn.
6. The lithium composite metal oxide according to claim 5 , wherein x in the composition formula (I) is 0<x≤0.2.
7. The lithium composite metal oxide according to claim 6 , wherein y+z+w in the composition formula (I) is 0<y+z+w≤0.3.
8. The lithium composite metal oxide according to claim 5 , wherein y+z+w in the composition formula (I) is 0<y+z+w≤0.3.
9. The lithium composite metal oxide according to claim 1 , wherein a volume-based 50% cumulative particle size (D 50 ) determined from the particle size distribution measurement is 500 nm or more and 9 mm or less.
10. A positive electrode active material for a lithium secondary battery, comprising the lithium composite metal oxide according to claim 1 .
11. A positive electrode for a lithium secondary battery, comprising the positive electrode active material for a lithium secondary battery according to claim 10 .
12. A lithium secondary battery, comprising the positive electrode for a lithium secondary battery according to claim 11 .