Positive active material, preparation process thereof, sodium ion battery and apparatus containing the same
A positive electrode active material and a preparation process thereof, a sodium ion battery ( 5 ) and an apparatus containing the sodium ion battery ( 5 ) are described, the positive electrode active material satisfying the chemical formula of Na 0.67 Mn x A y B z O 2±δ , in which A is selected from one or more of Co, Ni and Cr, B is selected from one or more of Mg, Al, Ca, Ti, Cu, Zn and Ba, 0.6<x<1, 0<y<0.1, 0.6<x+y<0.8, z>0, x+y+z=1, 0≤δ≤0.1, and (I) 3 . 3 3 + 2 ( δ - y - z ) 4 < x < 3 . 3 3 + 2 ( δ - y - z ) 3 .
1. A positive electrode active material satisfying the chemical formula of Na 0.67 Mn x A y B z O 2±δ , in which A is selected from one or more of Co, Ni and Cr, B is selected from one or more of Mg, Al, Ca, Ti, Cu, Zn and Ba, 0.6<x<1, 0<y<0.1, 0.6<x+y<0.8, z>0, x+y+z=1, 0≤δ≤0.1, and
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2. The positive electrode active material according to claim 1 , wherein the positive electrode active material satisfies 1≤z/y≤12.
3. The positive electrode active material according to claim 1 , wherein the positive electrode active material has a unit cell parameter that satisfies 3.8510≤c/a≤4.9000.
4. The positive active material according to claim 1 , wherein the positive active material has an average particle diameter Dv50 of 3 μm-20 μm.
5. The positive active material according to claim 1 , wherein the positive active material has a specific surface area of 0.01 m 2 /g-6 m 2 /g.
6. The positive active material according to claim 1 , wherein the positive active material has a hexagonal phase crystal structure.
7. The positive active material according to claim 1 , wherein the positive active material has a powder resistivity of 20 Ω·cm to 10000 Ω·cm under a pressure of 12 MPa.
8. The positive active material according to claim 1 , wherein the positive active material has a tap density of ≥1.5 g/cm 3 ; and/or,
the positive electrode active material has a compacted density of ≥3 g/cm 3 under a pressure of 8 tons.
9. The positive electrode active material according to claim 1 , wherein the positive electrode active material has a morphology in a polygonal sheet structure.
10. A process for preparing a positive electrode active material, comprising the following steps:
mixing a sodium precursor, manganese oxide, an oxide of A and an oxide of B to form a mixture, and then sintering the mixture to obtain the positive electrode active material;
wherein the positive electrode active material satisfies the chemical formula of Na 0.67 Mn x A y B z O 2±δ , in which A is selected from one or more of Co, Ni and Cr, B is selected from one or more of Mg, Al, Ca, Ti, Cu, Zn and Ba, 0.6<x<1, 0<y<0.1, 0.6<x+y<0.8, z>0, x+y+z=1, 0≤δ≤0.1, and
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2
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11. A sodium ion battery comprising a positive electrode plate, the positive electrode plate comprising the positive electrode active material according to claim 1 .
12. An apparatus comprising the sodium ion battery according to claim 11 .
13. The positive electrode active material according to claim 1 , wherein the positive electrode active material satisfies 3≤z/y≤9.
14. The positive electrode active material according to claim 1 , wherein the positive electrode active material has a unit cell parameter that satisfies 3.8602≤c/a≤3.8800.
15. The positive active material according to claim 1 , wherein the positive active material has an average particle diameter Dv50 of 5 μm-12 μm.
16. The positive active material according to claim 1 , wherein the positive active material has a specific surface area of 0.5 m 2 /g-4 m 2 /g.
17. The positive active material according to claim 1 , wherein the positive active material has a powder resistivity of 20 Ω·cm to 1000 Ω·cm under a pressure of 12 MPa.
18. The positive active material according to claim 1 , wherein the positive active material has a tap density of ≥1.5 g/cm 3 ; and/or,
the positive electrode active material has a compacted density of from 3.5 g/cm 3 to 5 g/cm 3 under a pressure of 8 tons.
19. The positive active material according to claim 1 , wherein the positive active material has a tap density of from 1.5 g/cm 3 to 3.0 g/cm 3 ; and/or,
the positive electrode active material has a compacted density of ≥3 g/cm 3 under a pressure of 8 tons.
20. The positive active material according to claim 1 , wherein the positive active material has a tap density of from 1.5 g/cm 3 to 3.0 g/cm 3 ; and/or,
the positive electrode active material has a compacted density of from 3.5 g/cm 3 to 5 g/cm 3 under a pressure of 8 tons.
21. The positive electrode active material according to claim 1 , wherein the positive electrode active material has a morphology in a hexagonal sheet structure.