Conducting composite current collector for a battery or supercapacitor and production process
Provided is a composite thin film current collector for a battery or supercapacitor, the thin film comprising graphene sheets dispersed in or bonded by an electron-conducting polymer network (also referred to as conducting network polymer, crosslinked polymer, or hydrogel polymer) wherein the composite thin film has a thickness from 2 nm to 500 μm and an electrical conductivity from 10 −4 to 10 4 S/cm and wherein the graphene sheets occupy from 10% to 99% by weight and the polymer network from 1% to 90% by weight of the total composite weight.
1 . A composite thin film for a battery or supercapacitor, said composite thin film comprising graphene sheets dispersed in or bonded by an electron-conducting polymer network, wherein said composite thin film has a thickness from 2 nm to 500 μm and an electrical conductivity from 10 −4 to 10 4 S/cm and wherein the graphene sheets occupy from 10% to 99% by weight and the polymer network from 1% to 90% by weight of the total composite weight, wherein said electron-conducting polymer network comprises chains of a conjugated polymer selected from poly(3-alkylthiophenes), poly(2,5-bis(cholestanoxy) phenylene vinylene), poly(2,5-dialkoxy) paraphenylene vinylene, poly[(1,4-phenylene-1,2-diphenylvinylene)], polyparaphenylene sulphide, polyheptadiyne, poly(3-octylthiophene), poly(3-cyclohexylthiophene), poly(3-methyl-4-cyclohexylthiophene), poly(2,5-dialkoxy-1,4-phenyleneethynylene), poly(2-decyloxy-1,4-phenylene), a derivative thereof, a copolymer thereof, or a combination thereof, or comprises polythiophene hydrogel polymer in a dehydrated state.
2 . The composite thin film of claim 1 , wherein the graphene sheets comprise sheets of a graphene material selected from pristine graphene, graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof.
3 . The composite thin film of claim 1 , wherein the graphene sheets comprise single-layer graphene or few-layer graphene, wherein a few-layer graphene sheet consists of 2-10 graphene planes.
4 . The composite thin film of claim 1 , wherein the graphene sheets in the composite thin film are aligned to be substantially parallel to one another.
5 . A current collector comprising the composite thin film of claim 1 .
6 . The current collector of claim 5 , wherein the current collector comprises a metal tab that is bonded to the composite thin film and is used as a terminal pole for connection to an external circuit.
7 . A current collector comprising a metal foil having two primary surfaces, wherein at least one of the primary surfaces is chemically bonded to the composite thin film of claim 1 to form the current collector.
8 . The current collector of claim 7 , wherein the metal foil is selected from Cu, Ti, Ni, stainless steel, Ti, or Al foil.
9 . The current collector of claim 7 , wherein a surface of the metal foil is free from a passivating layer.
10 . The current collector of claim 7 , wherein said metal foil is porous, containing surface pores, interior pores, or through-thickness holes.
11 . A battery or capacitor using the composite thin film of claim 1 as a current collector.
12 . A battery or capacitor comprising the current collector of claim 7 .
13 . A process of producing the composite thin film of claim 1 , said process comprising: (a) dispersing multiple graphene sheets in a reacting mass comprising an oligomer or a monomer, an initiator or catalyst, a curing or cross-linking agent, and/or a liquid solvent to form a reacting suspension; (b) depositing a wet layer of said reacting suspension onto at least one of the two primary surfaces of a solid substrate; and (c) polymerizing or crosslinking the reacting suspension and at least partially removing any liquid or unreacted ingredients to form said composite thin film supported by the solid substrate.
14 . The process of claim 13 , wherein (b) comprises a procedure selected from casting, coating, printing, spraying, painting, extrusion, or a combination thereof.
15 . The process of claim 13 , wherein the composite thin film has a layer thickness from 2 nm to 100 nm and the solid substrate comprises a metal foil having a thickness from 1 μm to 30 μm.
16 . The process of claim 13 , wherein said solid substrate comprises a metal foil selected from Cu, Ti, Ni, stainless steel, Ti, or Al foil.
17 . The process of claim 13 , wherein the solid substrate comprises a metal foil and the process further comprises a procedure of chemically etching a surface of the metal foil to remove a surface-borne passivating layer prior to (b).
18 . The process of claim 13 , wherein (b) and (c) include depositing and forming a layer of said composite thin film on each of said two primary surfaces of the solid substrate.
19 . The process of claim 13 , wherein said solid substrate comprises a metal foil that is porous, containing surface pores, interior pores, or through-thickness holes.
20 . The process of claim 13 , which is a roll-to-roll process wherein said (b) and (c) include feeding a continuous sheet of said solid substrate from a roller to a deposition zone, depositing a wet layer of said reacting suspension onto said at least one primary surface of said solid substrate, polymerizing or crosslinking the reacting suspension to form a composite film, and collecting the composite film on a collector roller.
21 . The process of claim 13 , wherein the solid substrate is selected from a sheet, film, or block of a glass, ceramic, plastic, rubber, or metal and the process further comprises peeling off the composite thin film from the solid substrate to obtain a free-standing composite thin film.
22 . The process of claim 13 , wherein (b) of depositing comprises subjecting the reacting suspension to a shear stress and/or conducting (c) of polymerizing or crosslinking the reacting suspension under compression to align the graphene sheets to be substantially parallel to one another.