Positive electrode plate, preparation method thereof and sodium-ion battery
The present disclosure provides a positive electrode plate, a preparation method thereof and a sodium-ion battery. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material film. The positive electrode active material film provided on the positive electrode current collector and comprises a positive electrode active material. The positive electrode active material comprises a prussian blue analogue material, a molecular formula of the prussian blue analogue material is A x M[M′(CN) 6 ] y , a water content of the positive electrode active material film is 100 μg/g˜5000 μg/g. The water content of the positive electrode active material film is controlled within a certain range, which can not only ensure the sodium-ion battery do not seriously swell during charge-discharge process, but also can ensure sodium-ion battery have excellent charge-discharge performance and cycle performance.
1. A positive electrode plate, comprising:
a positive electrode current collector; and
a positive electrode active material film provided on the positive electrode current collector and comprising a positive electrode active material;
wherein,
the positive electrode active material comprises a Prussian blue analogue material, a molecular formula of the Prussian blue analogue material is A x M[M′(CN) 6 ] y , where, A is one or more selected from a group consisting of alkali metal ion and alkaline-earth metal ion, M is a transition metal, M′ is a transition metal, 0<x≤2, 0<y<1;
a water content of the positive electrode active material film is 100 μg/g˜5000 μg/g.
2. The positive electrode plate according to claim 1 , wherein
A is one or more selected from a group consisting of Li + , Na + , K + , Mg + and Ca 2+ ;
M is one selected from a group consisting of Mn, Fe, Co, Ni, Cu, Zn, V and Cr;
M′ is one selected from a group consisting of Mn, Fe, Co, Ni, Cu, Zn, V and Cr.
3. The positive electrode plate according to claim 2 , wherein A is one or two selected from a group consisting of Na + and K + .
4. The positive electrode plate according to claim 1 , wherein the water content of the positive electrode active material film is 300 μg/g˜3000 μg/g.
5. The positive electrode plate according to claim 1 , wherein the positive electrode active material film further comprises a conductive agent, the conductive agent is one or more selected from a group consisting of conductive carbon black, conductive graphite, carbon nanotube and carbon nanofiber.
6. The positive electrode plate according to claim 1 , wherein the positive electrode active material film further comprises a binder, the binder is one or more selected from a group consisting of polyvinylidene fluoride binder, styrene butadiene rubber, sodium carboxymethylcellulose, sodium alginate, polyacrylic acid and polytetrafluoroethylene.
7. The positive electrode plate according to claim 5 , wherein the positive electrode active material film further comprises a binder, the binder is one or more selected from a group consisting of polyvinylidene fluoride binder, styrene butadiene rubber, sodium carboxymethylcellulose, sodium alginate, polyacrylic acid and polytetrafluoroethylene.
8. The positive electrode plate according to claim 1 , wherein a specific surface area of the positive electrode active material is 5 m 2 /g˜20 m 2 /g.
9. A preparation method of a positive electrode plate comprising steps of:
(1) fully mixing a Prussian blue analogue material with a molecular formula of A x M[M′(CN) 6 ] y which is prepared in advance, a conductive agent, a binder and a solvent and obtaining a positive electrode slurry, where, A is one or more selected from a group consisting of alkali metal ion and alkaline-earth metal ion, M is a transition metal, M′ is a transition metal, 0<x≤2, 0<y<1;
(2) coating the positive electrode slurry which is obtained in the step (1) on a positive electrode current collector, after drying and cold-pressing, obtaining an initial positive electrode plate;
(3) drying the initial positive electrode plate obtained in step (2) under vacuum, and controlling a water content of the positive electrode active material film to be 100 μg/g˜5000 μg/g, and obtaining a positive electrode plate.
10. The preparation method of the positive electrode plate according to claim 9 , wherein in the step (3), a vacuum degree of the drying under vacuum is less than or equal to −0.07 MPa.
11. The preparation method of the positive electrode plate according to claim 9 , wherein in the step (3), a temperature of the drying under vacuum is 85° C. ˜220° C.
12. A sodium-ion battery, comprising a positive electrode plate, the positive electrode plate comprising a positive electrode current collector and a positive electrode active material film, the positive electrode active material film being provided on the positive electrode current collector and comprising a positive electrode active material;
wherein,
the positive electrode active material comprises a Prussian blue analogue material, a molecular formula of the Prussian blue analogue material is A x M[M′(CN) 6 ] y , where, A is one or more selected from a group consisting of alkali metal ion and alkaline-earth metal ion, M is a transition metal, M′ is a transition metal, 0<x≤2, 0<y<1;
a water content of the positive electrode active material film is 100 μg/g˜5000 μg/g.
13. The sodium-ion battery according to claim 12 , wherein
A is one or more selected from a group consisting of Li + , Na + , K + , Mg + and Ca 2+ ;
M is one selected from a group consisting of Mn, Fe, Co, Ni, Cu, Zn, V and Cr;
M′ is one selected from a group consisting of Mn, Fe, Co, Ni, Cu, Zn, V and Cr.
14. The sodium-ion battery according to claim 13 , wherein A is one or two selected from a group consisting of Na + and K + .
15. The sodium-ion battery according to claim 12 , wherein the water content of the positive electrode active material film is 300 μg/g˜3000 μg/g.
16. The sodium-ion battery according to claim 12 , wherein the positive electrode active material film further comprises a conductive agent, the conductive agent is one or more selected from a group consisting of conductive carbon black, conductive graphite, carbon nanotube and carbon nanofiber.
17. The sodium-ion battery according to claim 12 , wherein the positive electrode active material film further comprises a binder, the binder is one or more selected from a group consisting of polyvinylidene fluoride binder, styrene butadiene rubber, sodium carboxymethylcellulose, sodium alginate, polyacrylic acid and polytetrafluoroethylene.
18. The sodium-ion battery according to claim 16 , wherein the positive electrode active material film further comprises a binder, the binder is one or more selected from a group consisting of polyvinylidene fluoride binder, styrene butadiene rubber, sodium carboxymethylcellulose, sodium alginate, polyacrylic acid and polytetrafluoroethylene.
19. The sodium-ion battery according to claim 12 , wherein a specific surface area of the positive electrode active material is 5 m 2 /g˜20 m 2 /g.