Compositions and methods for dry electrode films having reduced binder content
Materials and methods for preparing dry cathode electrode film including reduced binder content are described. The cathode electrode film may be a self-supporting film including a single binder. The binder loading may be 3 weight % or less. In a first aspect, a method for preparing a dry free standing electrode film for an energy storage device is provided, comprising nondestructively mixing a cathode active material, a porous carbon, and optionally a conductive carbon to form an active material mixture, adding a single fibrillizable binder to the active material mixture, nondestructively mixing to form an electrode film mixture, and calendering the electrode film mixture to form a free standing electrode film.
1. A dry electrode film of an energy storage device, comprising:
90 wt. % to 99 wt. % of a dry active material;
at most 8 wt. % of a porous carbon material; and
at most 2 wt. % of a dry binder, wherein the dry electrode film is free-standing.
2. The dry electrode film of claim 1 , comprising about 95 wt. % to about 98 wt. % of the dry active material.
3. The dry electrode film of claim 1 , wherein the dry active material comprises dry active material particles with a D 50 particle size of at least about 10 μm.
4. The dry electrode film of claim 3 , wherein the dry active material particles have a D 50 particle size of about 10 μm to about 20 μm.
5. The dry electrode film of claim 1 , wherein the dry active material is selected from at least one of a metal oxide, metal sulfide, a sulfur-carbon composite, a lithium metal oxide and a material including sulfur.
6. The dry electrode film of claim 1 , wherein the electrode film comprises about 1 wt. % to 2 wt. % of a dry binder.
7. The dry electrode film of claim 1 , wherein the dry binder consists essentially of a single dry binder.
8. The dry electrode film of claim 1 , wherein the dry binder comprises a dry fibrillizable binder.
9. The dry electrode film of claim 8 , wherein the dry fibrillizable binder comprises polytetrafluoroethylene (PTFE).
10. The dry electrode film of claim 1 , wherein the dry electrode film comprises about 1 wt. % to about 7 wt. % of a porous carbon material.
11. The dry electrode film of claim 1 , wherein the dry electrode film further comprises at most about 5 wt. % of a conductive additive.
12. The dry electrode film of claim 11 , wherein the conductive additive comprises a conductive carbon material.
13. The dry electrode film of claim 12 , wherein the conductive carbon material comprises carbon black.
14. An electrode comprising the dry electrode film of claim 1 contact with a current collector.
15. A lithium ion battery comprising the electrode of claim 14 .
16. The lithium ion battery of claim 15 , having a first cycle device efficiency of at least about 90%.
17. The lithium ion battery of any one of claim 16 , having a first cycle device efficiency of about 90% to about 94%.
18. A method of fabricating the dry electrode film of claim 1 for an energy storage device, comprising:
mixing the dry active material with the porous carbon material to form a dry active material mixture;
mixing the dry active material mixture with the dry binder to form a dry electrode film mixture; and
calendering the dry electrode film mixture to form the dry electrode film.
19. The method of claim 18 , wherein calendering the dry electrode film mixture comprises at most three passes through a calender.
20. The method of claim 18 , wherein at least one of the mixing of the dry active material and the porous carbon material and the mixing of the dry active material mixture with a dry binder is performed by a non-destructive mixing process.
21. The method of claim 20 , wherein the non-destructively mixing process is a resonant acoustic mixing process.
22. The method of claim 20 , wherein the non-destructively mixing process is performed by a blade type mixer with a tip speed of about 10 meters/min to about 40 meters/min.
23. The method of claim 18 , wherein at least one of the mixing of the dry active material and the porous carbon material and the mixing of the dry active material mixture with a dry binder is performed by a high shear process.
24. The method of claim 23 , wherein the high shear process comprises a jet milling process.
25. The dry electrode film of claim 18 , wherein the porous carbon material comprises activated carbon.