Positive electrode active material including lithium transition metal particles with graphene coating layer positive electrode and lithium ion secondary battery including the same
A positive electrode active material for lithium ion secondary battery includes: active material particles including one or more compounds including Li and a transition metal; and a coating layer coating at least a part of a surface of the active material particles. The coating layer includes at least one of graphene or multilayer graphene The coating layer has a Raman spectrum with a G band (a peak of 1530 cm −1 to 1630 cm −1 ), a D band (a peak of 1300 cm −1 to 1400 cm −1 ), and a 2D band (a peak of 2650 cm −1 to 2750 cm −1 ). At least the intensity of the 2D band normalized by the intensity of the G band (2D int /G int ) satisfies 0.05≤2D int /G int .
1. A positive electrode active material for lithium ion secondary battery, comprising:
active material particles including one or more compounds including Li and a transition metal; and
a coating layer coating at least a part of a surface of the active material particles,
wherein the coating layer includes at least one of graphene or multilayer graphene,
the coating layer has a Raman spectrum with a G band, a D band and a 2D band, where the G band is a peak of 1530 cm −1 to 1630 cm −1 , the D band is a peak of 1300 cm −1 to 1400 cm −1 , and the 2D band is a peak of 2650 cm −1 to 2750 cm −1 ,
at least the intensity of the 2D band normalized by the intensity of the G band (2D int /G int ) satisfies 0.05≤2D int /G int ≤0.438, and
the intensity of the D band normalized by the intensity of the G band (D int /G int ) satisfies 0.513≤D int /G int ≤0.964.
2. The positive electrode active material for lithium ion secondary battery according to claim 1 , wherein the intensity of the D band normalized by the intensity of the G band (D int /G int ) satisfies 0.6≤D int /G int ≤0.964.
3. The positive electrode active material for lithium ion secondary battery according to claim 1 , wherein the intensity of the 2D band normalized by the intensity of the G band (2D int /G int ) satisfies 0.1≤2D int /G int ≤0.438.
4. The positive electrode active material for lithium ion secondary battery according to claim 3 , wherein the intensity of the D band normalized by the intensity of the G band (D int /G int ) satisfies 0.6≤D int /G int ≤0.964.
5. A positive electrode for lithium ion secondary battery, comprising the positive electrode active material for lithium ion secondary battery according to claim 1 .
6. A positive electrode for lithium ion secondary battery, the electrode comprising the positive electrode active material for lithium ion secondary battery according to claim 2 .
7. A positive electrode for lithium ion secondary battery, comprising the positive electrode active material for lithium ion secondary battery according to claim 3 .
8. A positive electrode for lithium ion secondary battery, comprising the positive electrode active material for lithium ion secondary battery according to claim 4 .
9. A lithium ion secondary battery comprising:
the positive electrode for lithium ion secondary battery according to claim 5 ;
a negative electrode including a negative electrode active material;
a separator disposed between the positive electrode and the negative electrode; and
a nonaqueous electrolyte.
10. A lithium ion secondary battery comprising:
the positive electrode for lithium ion secondary battery according to claim 6 ;
a negative electrode including a negative electrode active material;
a separator disposed between the positive electrode and the negative electrode; and
a nonaqueous electrolyte.
11. A lithium ion secondary battery comprising:
the positive electrode for lithium ion secondary battery according to claim 7 ;
a negative electrode including a negative electrode active material;
a separator disposed between the positive electrode and the negative electrode; and
a nonaqueous electrolyte.
12. A lithium ion secondary battery comprising:
the positive electrode for lithium ion secondary battery according to claim 8 ;
a negative electrode including a negative electrode active material;
a separator disposed between the positive electrode and the negative electrode; and
a nonaqueous electrolyte.