Aqueous-based solid polymer suspensions in a polymer solution as a binder for Si dominant anodes
Systems and methods utilizing aqueous-based polymer binders for silicon-dominant anodes may include an electrode coating layer on a current collector, where the electrode coating layer is formed from silicon and an aqueous-based suspension-solution binder composition comprising a water soluble (aqueous-based) polymer as part of a multi-component binder composition that also contains an water insoluble polymer. The electrode coating layer may include more than 70% silicon and the anode may be in a lithium ion battery.
1. A method of forming an electrode, the method comprising:
creating an electrode coating layer from an electrode slurry comprising silicon powder and a binder composition, where the binder composition comprises a water-insoluble polymeric component and a water-soluble polymer component;
fabricating a battery electrode by coating the slurry on a current collector; and
pyrolyzing said electrode coating layer;
wherein said water-soluble polymer component comprises an aqueous solution of a water soluble polymer.
2. The method according to claim 1 , wherein said water-insoluble polymeric component is a nano-micro size solid polymer component.
3. The method according to claim 2 , wherein said nano-micro size solid polymer component comprises particulates, beads, flakes or rods.
4. The method according to claim 1 , wherein said water-insoluble polymeric component comprises an insoluble polymer powder.
5. The method according to claim 1 , wherein said water-insoluble polymeric component is one or more of polyacrylonitrile (PAN), polyetherimide (PEI), PAI (poly amide-imide), polyimine and polyimide (PI).
6. The method according to claim 1 , wherein said water-soluble polymer is one or more of carboxymethyl cellulose (CMC), sucrose, poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), starch, chitosan, lignin, and gums.
7. The method according to claim 1 , wherein said electrode coating layer is dried, resulting in an electrode coating layer comprising a layer of dried solids.
8. The method according to claim 7 , wherein said electrode coating layer comprising a layer of dried solids is further pyrolyzed into carbon during making of the electrode.
9. The method according to claim 8 , wherein said electrode coating layer has a char yield upon pyrolysis of 40-60% by weight.
10. The method according to claim 1 , wherein having one or more additional component in the binder composition.
11. The method according to claim 10 , wherein said additional component is a conductive additive.
12. The method according to claim 11 , wherein said conductive additive comprises one or more of Super P, carbon black, graphite, graphene, carbon nano/micro fibers, carbon nanotubes, and porous (meso/macro) carbons.
13. The method according to claim 1 , wherein the electrode is in electrical and physical contact with an electrolyte, the electrolyte comprising a liquid, solid, or gel.
14. The method according to claim 1 , wherein the battery electrode is in a lithium ion battery.