Positive active material, positive electrode plate, electrochemical energy storage apparatus, and apparatus
This application provides a positive active material, a positive electrode plate, an electrochemical energy storage apparatus, and an apparatus. The positive active material is Li x Ni y Co z M k Me p O r A m , or Li x Ni y Co z M k Me p O r A m with a coating layer on its surface; and the positive active material is single crystal or quasi-single crystal particles, and a particle size D n 10 of the positive active material satisfies: 0.3 μm≤D n 10≤2 μm. In this application, particle morphology of the positive active material and an amount of micro powder in the positive active material are properly controlled, to effectively reduce side reactions between the positive active material and an electrolyte solution, decrease gas production of the electrochemical energy storage apparatus, and improve storage performance of the electrochemical energy storage apparatus without deteriorating an energy density, cycle performance, and rate performance of the electrochemical energy storage apparatus.
1. An electrochemical energy storage apparatus, wherein the electrochemical energy storage apparatus comprising positive active material and negative active material, the positive active material is ternary materials comprising Ni, Co, and M, the ratio of nickel, cobalt and manganese is y:z:k, y+z+k=1, 0.7≤y≤0.9, M is selected from one or two of Mn and Al;
the actual specific surface area BET2 of the positive active material is 0.5 m 2 /g to 1.5 m 2 /g;
the particle size Dn10 of the positive active material satisfies: 0.3 μm≤Dn10≤2 μm, the particle size Dv10 of the positive active material satisfies: 0.5 μm≤Dv10≤3 μm;
Dn10 is a corresponding particle size when a cumulative number distribution percentage of the positive active material reaches 10%;
Dv10 is a corresponding particle size when a cumulative volume distribution percentage of the positive active material reaches 10%.
2. The electrochemical energy storage apparatus according to claim 1 , wherein the particle size Dn10 of the positive active material satisfies:
0.5 μm≤Dn10≤1.5 μm.
3. The electrochemical energy storage apparatus according to claim 1 , wherein the particle size Dv10 of the positive active material satisfies: 1 μm≤Dv10≤2 μm.
4. The electrochemical energy storage apparatus according to claim 1 , the positive active material is single crystal or quasi-single crystal particles.
5. The electrochemical energy storage apparatus according to claim 1 , wherein the surface of positive active material comprising a coating layer, the coating layer comprising one or more coating elements.
6. The electrochemical energy storage apparatus according to claim 5 , wherein the one or more coating elements selected from Al, Ba, Zn, Ti, Co, W, Y, Si, Sn, B, and P.
7. The electrochemical energy storage apparatus according to claim 5 , wherein the coating layer comprising at least two coating elements.
8. The electrochemical energy storage apparatus according to claim 5 , wherein the content of Li 2 CO 3 on the surface of the positive active material is less than that of LiOH.
9. The electrochemical energy storage apparatus according to claim 8 , wherein the content of Li 2 CO 3 is less than 3000 ppm, and the content of LiOH is less than 5000 ppm.
10. The electrochemical energy storage apparatus according to claim 1 , wherein the particle size D v 50 of the positive active material is 1 μm to 6 μm.
11. The electrochemical energy storage apparatus according to claim 1 , wherein the particle size D v 50 of the positive active material is 2 μm to 5 μm.
12. The electrochemical energy storage apparatus according to claim 1 wherein the particle size Dn10 of the positive active material measured in μm and a particle size Dv10 of the positive active material measured in μm satisfy: 0.15≤Dn10×Dv10≤6.
13. The electrochemical energy storage apparatus according to claim 1 , wherein a theoretical specific surface area BET 1 of the positive active material and an actual specific surface area BET 2 of the positive active material satisfy: 0.3≤(BET 2 −BET 1 )/BET 1 ≤5.5, BET 1 =6/(ρ×D v 50), ρ is an actual density of the positive active material, and a unit of measurement is g/cm 3 ; and D v 50 is a corresponding particle size when the cumulative volume distribution percentage of the positive active material reaches 50%, and a unit of measurement is μm.
14. The electrochemical energy storage apparatus according to claim 1 , wherein the negative active material comprising one or a combination of silicon-oxygen compound, and a silicon-carbon composite.
15. The electrochemical energy storage apparatus according to claim 1 , wherein the electrochemical energy storage apparatus also comprising an electrolyte solution, the electrolyte solution comprising electrolyte and solvent, concentration of the electrolyte is 0.8 mol/L to 1.5 mol/L, the electrolyte comprising one or a combination of LiPF 6 , and LiN(SO 2 F) 2 (LiFSI).