Positive-electrode active material containing lithium composite oxide, and battery including the same
A positive-electrode active material contains a lithium composite oxide containing manganese. The crystal structure of the lithium composite oxide belongs to a space group Fd-3m. The integrated intensity ratio I (111) /I (400) of a first peak I (111) on the (111) plane to a second peak I (400) on the (400) plane in an XRD pattern of the lithium composite oxide satisfies 0.05≤I (111) /I (400) ≤0.90.
1. A positive-electrode active material comprising
a lithium composite oxide represented by a formula Li x Me y O α Q β , where Me is Mn or Me is Mn and at least one selected from the group consisting of Co, Ni, Fe, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, W, B, Si, P, and Al; Q is at least one selected from the group consisting of F, Cl, N, and S; 1.05≤x≤1.4; 0.6≤y≤0.95; x+y=2; 1.33≤α≤2; and 0≤β≤0.67,
wherein a crystal structure of the lithium composite oxide belongs to a space group Fd-3m, and
an integrated intensity ratio I (111) /I (400) of a first peak I (111) on a (111) plane to a second peak I (400) on a (400) plane in an X-ray diffraction (XRD) pattern of the lithium composite oxide satisfies 0.05≤I (111) /I (400) ≤0.90.
2. The positive-electrode active material according to claim 1 , wherein
0.05≤I (111) /I (400) ≤0.70.
3. The positive-electrode active material according to claim 2 , wherein
0.05≤I (111) /I (400) ≤0.30.
4. The positive-electrode active material according to claim 1 , wherein Me is Mn.
5. The positive-electrode active material according to claim 1 , wherein
Me is Mn and at least one selected from the group consisting of Co, Ni, Fe, Cu, V, Nb, Ti, Cr, Ru, W, B, Si, P, and Al.
6. The positive-electrode active material according to claim 1 , wherein
Mn constitutes 50 mol % or more of Me.
7. The positive-electrode active material according to claim 1 , wherein
Q includes F.
8. The positive-electrode active material according to claim 7 , wherein
Q is F.
9. The positive-electrode active material according to claim 1 , wherein
1.1≤x≤1.2, and
y=0.8.
10. The positive-electrode active material according to claim 1 , wherein
1.67≤α≤2, and
0−β≤0.33.
11. The positive-electrode active material according to claim 10 , wherein
1.67≤α<2, and
0<β≤0.33.
12. The positive-electrode active material according to claim 10 , wherein
1.67≤α≤1.9, and
0.1≤β≤0.33.
13. The positive-electrode active material according to claim 1 , wherein
1.3≤x/y≤1.9.
14. The positive-electrode active material according to claim 13 , wherein
1.38≤x/y≤1.5.
15. The positive-electrode active material according to claim 1 , wherein
5≤α/β≤19.
16. The positive-electrode active material according to claim 1 , wherein
0.75≤(x+y)/(α+β)≤1.2.
17. The positive-electrode active material according to claim 16 , wherein
0.95≤(x+y)/(α+β)≤1.0.
18. A battery comprising:
a positive electrode including the positive-electrode active material according to claim 1 ;
a negative electrode; and
an electrolyte.
19. The battery according to claim 18 , wherein
the negative electrode includes a negative-electrode active material which lithium ions are occluded in and released from, or a material which lithium metal is dissolved from and deposited on, and
the electrolyte is a non-aqueous electrolyte solution.
20. The battery according to claim 18 , wherein
the negative electrode includes a negative-electrode active material which lithium ions are occluded in and released from, or a material which lithium metal is dissolved from and deposited on, and
the electrolyte is a solid electrolyte.