Positive electrode material and preparation method and usage thereof
This disclosure relates to the electrochemical field, and in particular, to a positive electrode material and a preparation method and usage thereof. The positive electrode material of this disclosure includes a substrate, where a general formula of the substrate is Li x Ni y Co z M k Me p O r A m , where 0.95≤x≤1.05, 0.5≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤5.2, 0≤m≤2, m+r≤2, M is selected from one or more of Mn and Al, Me is selected from one or more of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, and Nb, and A is selected from one or more of N, F, S, and Cl; and an oxygen defect level of the positive electrode material satisfies at least one of condition (1) or condition (2): (1) 1.77≤OD1≤1.90; or (2) 0.69≤OD2≤0.74.
1. A positive electrode material, comprising a substrate,
wherein a general formula of the substrate is Li x Ni y Co z M k Me p O r A m , wherein 0.95≤x≤1.05, 0.5≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤5.2, 0≤m≤2, m+r≤2, M is selected from Mn and/or Al, Me is selected from one or more of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, and Nb, and A is selected from one or more of N, F, S, and Cl; and
an oxygen defect level of the positive electrode material satisfies at least one of condition (1) and condition (2):
(1) 1.77≤OD1≤1.90, wherein OD1=(I 101 /I 012 ) 0.5 , I 101 represents XRD diffraction peak intensity of the (101) crystal plane of the positive electrode material in an XRD pattern, and I 012 represents diffraction peak intensity of the (012) crystal plane of the positive electrode material in the XRD pattern; and
(2) 0.69≤OD2≤0.74, wherein OD2=(I 101 /I 104 ) 0.5 , I 101 represents the XRD diffraction peak intensity of the (101) crystal plane of the positive electrode material in the XRD pattern, and 1104 represents diffraction peak intensity of the (104) crystal plane of the positive electrode material in the XRD pattern; wherein a mean microstress (MMS) of the positive electrode material ranges from 0.03 to 0.20, wherein MMS=(β hkl ·cot θ hkl /4, β hkl represents a half-peak width of a characteristic diffraction peak (hkl) in the XRD pattern of the positive electrode material, and θ hkl represents a diffraction angle corresponding to the characteristic diffraction peak (hkl) in the XRD pattern of the positive electrode material.
2. The positive electrode material according to claim 1 , wherein when the positive electrode material is single-crystal particles, OD1 ranges from 1.77 to 1.87; and when the positive electrode material is secondary particles, OD1 ranges from 1.79 to 1.90.
3. The positive electrode material according to claim 1 , wherein when the positive electrode material is single-crystal particles, OD2 ranges from 0.69 to 0.72; and when the positive electrode material is secondary particles, OD2 ranges from 0.70 to 0.74.
4. The positive electrode material according to claim 1 , wherein a Li/Ni mixing ratio of the positive electrode material is 0.1% to 3%.
5. The positive electrode material according to claim 1 , wherein the substrate internally contains a doping element, and the doping element is selected from one or more of Al, Co, Cd, Mo, B, P, and Ag.
6. The positive electrode material according to claim 1 , wherein the positive electrode material further comprises a coating layer located on a surface of the substrate, the coating layer comprises a coating element, and the coating element is selected from one or more of Al, Ba, Zn, Ti, W, Y, Si, Sn, and B.
7. The positive electrode material according to claim 6 , wherein a content ratio of the coating element in the positive electrode material is 100 ppm to 3000 ppm.
8. The positive electrode material according to claim 6 , wherein a content ratio of the coating element in the positive electrode material is 200 ppm to 2000 ppm.
9. The positive electrode material according to claim 1 , wherein powder resistivity p of the positive electrode material under 12 MPa is 10 Ω·cm to 4500 Ω·cm.
10. The positive electrode material according to claim 9 , wherein the powder resistivity p is 1000Ω·cm to 4000Ω·cm.
11. The positive electrode material according to claim 1 , wherein in residual lithium on the surface of the positive electrode material, Li 2 CO 3 content is less than 3000 ppm, and LiOH content is less than 5000 ppm.
12. The positive electrode material according to claim 11 , wherein the Li 2 CO 3 content is less than the LiOH content.
13. The positive electrode material according to claim 1 , wherein a Li/Ni mixing ratio of the positive electrode material is 0.5% to 2%.
14. The positive electrode material according to claim 1 , wherein when the positive electrode material is single crystal particles, MMS ranges from 0.03 to 0.07; and when the positive electrode material is secondary particles, MMS ranges from 0.07 to 0.20.
15. A positive electrode plate, comprising a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer comprises the positive electrode material according to claim 1 .
16. An electrochemical energy storage apparatus, comprising the positive electrode material according to claim 1 .