Cathode active material used for lithium ion secondary battery and lithium ion secondary battery
The present invention is to provide a cathode active material used for a lithium ion secondary battery which has a large charge-discharge capacity, and excels in charge-discharge cycle properties, output properties and productivity, and, a lithium ion secondary battery using the same. The cathode active material used for a lithium ion secondary battery comprises a lithium transition metal composite oxide represented by the following Formula (1); Li 1+a Ni b Co c Mn d M e O 2+α , where, in the formula (1), M is at least one metal element other than Li, Ni, Co, and Mn; and a, b, c, d, e, and α satisfy the following conditions: −0.04≤a≤0.04, 0.80≤b<1.00, 0≤c≤0.04, 0<d<0.20, b+c+d+e=1, −0.2<α<0.2, and c and d in the Formula (1) satisfy c/d≤0.75.
1. A cathode active material used for a lithium ion secondary battery comprising:
a lithium transition metal composite oxide represented by the following Formula (1):
Li 1+a Ni b Co c Mn d MeO 2+α (1)
where M contains at least one kind of metal elements selected from a group consisting of Al, Ti, Zn, Ga, Zr, Mo, Nb, V, Sn, Mg, Ta, Ba, W and Y; a, b, c, d, e, and a are respectively numbers satisfying the following conditions: −0.04≤a≤0.04, 0.80≤b<1.00, 0.01≤c≤0.04, 0<d<0.20, b+c+d+e=1, −0.2<α<0.2, wherein
c and d in the Formula (1) satisfy 0<c/d≤0.75.
2. The cathode active material used for a lithium ion secondary battery according to the claim 1 , wherein
the lithium transition metal composite oxide represented by the Formula (1) has an α-NaFeO 2 type crystal structure, and
a site occupancy of nickel at a 3a site in a crystal structure belonging to a space group R-3m is less than 4%.
3. The cathode active material used for a lithium ion secondary battery according to the claim 1 , having an X-ray powder diffraction spectrum obtained using a CuKα radiation, wherein
I (003) and I (104) are defined as an integrated intensity of a diffraction peak assigned to planes (003) and (104) respectively, and
a value of I (003) /I (104) is 1.2 or more.
4. The cathode active material used for a lithium ion secondary battery according to the claim 1 , having an X-ray powder diffraction spectrum obtained using a CuKα radiation, wherein
a full width at half maximum of a diffraction peak assigned to a plane (003) is 0.130° or smaller.
5. The cathode active material used for a lithium ion secondary battery according to the claim 1 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
6. The cathode active material used for a lithium ion secondary battery according to the claim 1 having a specific surface area of 0.2 m 2 /g or more and 1.5 m 2 /g or less.
7. A lithium ion secondary battery comprising a cathode comprising the cathode active material used for a lithium ion secondary battery according to the claim 1 .
8. The cathode active material used for a lithium ion secondary battery according to the claim 2 , having an X-ray powder diffraction spectrum obtained using a CuKα radiation, wherein
I (003) and I (104) are defined as an integrated intensity of a diffraction peak assigned to planes (003) and (104) respectively, and
a value of I (003) /I (104) is 1.2 or more.
9. The cathode active material used for a lithium ion secondary battery according to the claim 2 , having an X-ray powder diffraction spectrum obtained using a CuKα radiation, wherein
a full width at half maximum of a diffraction peak assigned to a plane (003) is 0.130° or smaller.
10. The cathode active material used for a lithium ion secondary battery according to the claim 3 , having an X-ray powder diffraction spectrum obtained using a CuKα radiation, wherein
a full width at half maximum of a diffraction peak assigned to a plane (003) is 0.130° or smaller.
11. The cathode active material used for a lithium ion secondary battery according to the claim 8 , having an X-ray powder diffraction spectrum obtained using a CuKα radiation, wherein
a full width at half maximum of a diffraction peak assigned to a plane (003) is 0.130° or smaller.
12. The cathode active material used for a lithium ion secondary battery according to the claim 2 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
13. The cathode active material used for a lithium ion secondary battery according to the claim 3 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
14. The cathode active material used for a lithium ion secondary battery according to the claim 8 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
15. The cathode active material used for a lithium ion secondary battery according to the claim 9 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
16. The cathode active material used for a lithium ion secondary battery according to the claim 10 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
17. The cathode active material used for a lithium ion secondary battery according to the claim 11 , wherein
an a-axis lattice constant of a unit lattice is 2.878×10 −10 m or more.
18. The cathode active material used for a lithium ion secondary battery according to the claim 1 , wherein M is Ti.