Dry energy storage device electrode and methods of making the same
An energy storage device can include a cathode and an anode, where at least one of the cathode and the anode are made of a polytetrafluoroethylene (PTFE) composite binder material including PTFE and at least one of polyvinylidene fluoride (PVDF), a PVDF co-polymer, and poly(ethylene oxide) (PEO). The energy storage device can be a lithium ion battery, a lithium ion capacitor, and/or any other lithium based energy storage device. The PTFE composite binder material can have a ratio of about 1:1 of PTFE to a non-PTFE component, such a PVDF, PVDF co-polymer and/or PEO. Methods of fabricating the anode and/or the cathode of the energy storage device are also disclosed.
1. A method of fabricating an anode of an energy storage device, comprising:
combining an active material and at least one component of a composite binder material to form a first mixture, wherein the at least one component comprises at least one of polyvinylidene fluoride (PVDF), a PVDF co-polymer, and poly(ethylene oxide) (PEO);
adding PTFE to the first mixture to form a second mixture; and
subjecting the second mixture to a process to form an electrode film mixture,
wherein subjecting the second mixture to the process comprises fibrillizing the PTFE.
2. The method of claim 1 , wherein each of the combining and the adding steps comprises blending at a temperature of 20° C. to 75° C.
3. The method of claim 1 , wherein the fibrillizing comprises jet-milling.
4. The method of claim 1 , wherein combining further comprises combining a conductive carbon additive with the active material and the at least one component of the composite binder material to form the first mixture.
5. The method of claim 4 , wherein the conductive carbon additive comprises carbon black.
6. The method of claim 1 , wherein a mass ratio of the PTFE to the at least one component is 1:3 to 3:1.
7. The method of claim 1 , wherein the method is a dry fabrication process.
8. The method of claim 1 , further comprising calendering the electrode film mixture to form a free-standing anode film.
9. The method of claim 8 , further comprising disposing the anode film over a current collector to form an anode.
10. The method of claim 9 , wherein the disposing comprises laminating the anode film to the current collector.
11. The method of claim 10 , wherein the laminating is performed at a temperature of about 100° C. to about 200° C.
12. The method of claim 8 , wherein the calendering is performed at a temperature sufficient to melt the at least one component.
13. The method of claim 8 , wherein the calendering is performed at a temperature of about 140° C. to about 300° C.
14. The method of claim 1 , wherein a mass ratio of the PTFE to the at least one component is 1:5 to 5:1.
15. The method of claim 1 , wherein the process comprises a high shear process with a grinding pressure of more than about 40 psi.
16. The method of claim 1 , wherein the active material comprises a lithium ion intercalating carbon component.
17. The method of claim 1 , wherein the active material comprises synthetic graphite, natural graphite, hard carbon, soft carbon, graphene, mesoporous carbon, silicon, silicon oxides, tin, tin oxides, germanium, lithium titanate, or mixtures or composites thereof.
18. The method of claim 17 , wherein the active material comprises synthetic graphite, natural graphite, or combinations thereof.
19. A method of fabricating an energy storage device, comprising:
inserting the anode of claim 9 , a cathode and a separator within a housing, wherein the separator is positioned between the anode and the cathode.
20. The method of claim 19 , wherein the energy storage device is a lithium ion battery or a lithium ion capacitor.