Compositions and methods for passivation of electrode binders
Passivation methods and compositions for electrode binders are disclosed. A coated binder particle for use in an electrode film of an energy storage device is provided. The coated binder particle can comprise a coating over the surface of a binder particle, wherein the coating provides ionic insulation to the binder particle. In some embodiments, the coating covers the entire surface of the binder particle. In still further embodiments, a coated binder particle in an energy storage device blocks ionic contact between the binder and an electrolyte.
1 . An electrode film comprising:
active material particles; and
fibrillized polymeric binder particles coated with a coating material;
wherein the coating material is ionically insulating and electrically conductive;
wherein the fibrillized polymeric binder particles form a matrix within the electrode film such that the electrode film is self-supporting; and
wherein at least about 70% of an average surface of the fibrillized polymeric binder particles are coated with the coating material.
2 . The electrode film of claim 1 , wherein the fibrillized polymeric binder particles comprise a binder selected from the group consisting of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), polyvinylidene fluoride (PVDF), a PVDF co-polymer, poly(ethylene oxide) (PEO), and combinations thereof.
3 . The electrode film of claim 1 , wherein the active material particles comprise a material selected from the group consisting of graphite, hard carbon, soft carbon, graphene, mesoporous carbon, silicon, a silicon oxide, tin, a tin oxide, germanium, lithium titanate, combinations thereof, and composites thereof.
4 . The electrode film of claim 1 , wherein the fibrillized polymeric binder particles form composite particles with the coating material.
5 . The electrode film of claim 4 , wherein the fibrillized polymeric binder particles comprise composite particles of PTFE and conductive carbon.
6 . The electrode film of claim 1 , wherein the coating material comprises a material selected from the group consisting of carbon black, conductive carbon, graphene-containing carbon, graphite, and combinations thereof.
7 . The electrode film of claim 1 , wherein the coating material further comprises a ductile metal.
8 . The electrode film of claim 7 , wherein the ductile metal is selected from the group consisting of Cu, Sn, Sb, and combinations thereof.
9 . The electrode film of claim 1 , wherein the coating material comprises conductive carbon.
10 . The electrode film of claim 1 , wherein at least about 90% of the average surface of the fibrillized polymeric binder particles are coated with the coating material.
11 . The electrode film of claim 1 , wherein about 80% to 90% of an average surface of the fibrillized polymeric binder particles are coated with the coating material.
12 . The electrode film of claim 1 , wherein the electrode film is substantially free from solvent residue.
13 . The electrode film of claim 1 , wherein the total mass of the coating material is about 1-50% the total mass of the fibrillized polymeric binder particles.
14 . The electrode film of claim 1 , wherein the thickness of the coating material coated on the fibrillized polymeric binder particles is about 0.1-100 microns.
15 . An electrode, comprising the electrode film of claim 1 and a current collector.
16 . An energy storage device comprising the electrode of claim 15 .
17 . The energy storage device of claim 16 , further comprising an electrolyte comprising lithium ions in contact with the electrode film.
18 . The energy storage device of claim 17 , wherein the fibrillized polymeric binder particles are insulated from contact with the lithium ions.
19 . The energy storage device of claim 16 , wherein the energy storage device is a battery.
20 . The energy storage device of claim 16 , wherein the energy storage device is configured to maintain at least 75% of its initial capacity when operating for a period of at least 1500 hours at about 65° C. or greater.
21 . An electrode film comprising:
active material particles; and
fibrillized polymeric binder particles coated with a coating material;
wherein the coating material is ionically insulating and electrically conductive;
wherein the fibrillized polymeric binder particles form a matrix within the electrode film such that the electrode film is self-supporting; and
wherein the total mass of the coating material is about 1-50% the total mass of the fibrillized polymeric binder particles.
22 . An electrode film comprising:
active material particles; and
fibrillized polymeric binder particles coated with a coating material;
wherein the coating material is ionically insulating and electrically conductive;
wherein the fibrillized polymeric binder particles form a matrix within the electrode film such that the electrode film is self-supporting; and
wherein the thickness of the coating material coated on the fibrillized polymeric binder particles is about 0.1-100 microns.