Lithium metal composite oxide, positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery
The present invention relates to a lithium metal composite oxide represented by the composition formula (I), the lithium metal composite oxide satisfies requirements (1) to (3): (1) a ratio (I 1 /I 2 ) of an integral intensity I 1 of a diffraction peak in a range of 2θ=36.7±1° with respect to an integral intensity I 2 of a diffraction peak in a range of 2θ=64.9±1° in a powder X-ray diffraction measurement for the lithium metal composite oxide using Cu-Kα ray is 2.0 or more; (2) a BET specific surface area is 0.7 m 2 /g or less; and (3) a 10% cumulative volume particle size D 10 is 5 μm or more.
1 . A lithium metal composite oxide represented by the following composition formula (I), the lithium metal composite oxide satisfies requirements (1) to (3):
Li[Li x (Ni 1-y-z-w) Co y Mn z M w ) 1-x ]O 2 (I)
wherein M is one or more elements selected from the group consisting of P, Fe, Cu, Ti, Mg, Al, W, B, Mo, Nb, Zn, Sn, Zr, Ga and V, and −0.1≤x≤0.2, 0≤y≤0.4, 0≤z≤0.4 and 0≤w≤0.1 are satisfied;
(1) a ratio (I 1 /I 2 ) of an integral intensity I 1 of a diffraction peak in a range of 2θ=36.7±1° with respect to an integral intensity I 2 of a diffraction peak in a range of 2θ=64.9±1° in a powder X-ray diffraction measurement for the lithium metal composite oxide using Cu-Kα ray is 2.0 or more;
(2) a BET specific surface area is 0.7 m 2 /g or less; and
(3) a 10% cumulative volume particle size D 10 is 5 μm or more, and
wherein the lithium metal composite oxide that satisfies the requirements (1) to (3) has been washed with a washing liquid containing water.
2 . The lithium metal composite oxide according to claim 1 ,
wherein a ratio (D 50 /average primary particle diameter) of a 50% cumulative volume particle size D 50 with respect to an average primary particle diameter is 2.0 or less.
3 . The lithium metal composite oxide according to claim 1 ,
wherein an average primary particle diameter is 4.5 μm or more.
4 . The lithium metal composite oxide according to claim 1 ,
wherein y is 0.5 times or more and 5 times or less of z in the composition formula (I).
5 . A positive electrode active material for a lithium secondary battery, which comprises the lithium metal composite oxide of claim 1 .
6 . A positive electrode for a lithium secondary battery, which comprises the positive electrode active material of claim 5 .
7 . A lithium secondary battery comprising the positive electrode of claim 6 .