Graphene electrode

Abstract

An electrode with a relatively high surface area formed substantially from graphene sheets.

1 . An electrode with a relatively high surface area formed substantially from graphene sheets. 
     
     
         2 . An electrode according to  claim 1  with a relatively high mesoporous volume, adapted for use in the capacitive separation of ions. 
     
     
         3 . An electrode according to  claim 2  adapted for use in the capacitive deionisation of saline solutions. 
     
     
         4 . An electrode according to  claim 2  adapted for use in the capacitive energy storage in aqueous media. 
     
     
         5 . An electrode according to  claim 2  adapted for use in the capacitive energy storage in non-aqueous media. 
     
     
         6 . An electrode according to  claim 2  adapted for use in both capacitive energy storage in aqueous media and capacitive desalination of water. 
     
     
         7 . An electrode according to  claim 2 , wherein the relatively high mesoporous volume is produced by incorporation of spacers between the graphene sheets. 
     
     
         8 . An electrode according to  claim 7  where the spacers are bound to the graphene sheets in a graphene dispersion. 
     
     
         9 . An electrode according to  claim 7  where the spacers are incorporated between the graphene sheets during conversion of the graphene dispersion to agglomerates. 
     
     
         10 . An electrode according to  claim 7  where the spacers are incorporated between the graphene sheets during conversion of the graphene dispersion to an electrode. 
     
     
         11 . An electrode according to  claim 10  where the spacer is a polymer that is also used to bind the graphene sheets together or to a substrate, preferably said polymer is selected from a group consisting of CMC, SBR, PvDF and PTFE. 
     
     
         12 . An electrode according to  claim 7  where the spacers are incorporated between the graphene sheets by co-precipitation from a charge stabilised dispersion of graphene containing the spacer. 
     
     
         13 . An electrode according to  claim 7  where the spacers are incorporated between the graphene sheets by filtration from a charge stabilised dispersion of graphene containing the spacer. 
     
     
         14 . An electrode according to  claim 7  where the spacers are incorporated between the graphene sheets by evaporation of the solvent from a charge stabilised dispersion of graphene containing the spacer in said solvent. 
     
     
         15 . An electrode according to  claim 7  where the spacers are carbon particles or fibres. 
     
     
         16 . An electrode according to  claim 15  where the carbon particles are selected from a group containing: carbon black; carbon nanotubes; carbon nano-onions and carbon nano-fibres. 
     
     
         17 . An electrode according to  claim 7  where the spacers are oxide particles. 
     
     
         18 . An electrode according to  claim 17  where the oxide particles are substantially manganese oxide, or titanium oxide, or iron oxide. 
     
     
         19 . An electrode according to  claim 17  where the oxide particles are substantially aluminium oxide, or zirconium oxide, or silicon oxide. 
     
     
         20 . An electrode according to  claim 7  where the spacers are silicon particles. 
     
     
         21 . An electrode according to  claim 7  where the spacers are nitride particles. 
     
     
         22 . An electrode according to  claim 7  where the spacers are polymers or large molecules. 
     
     
         23 . An electrode according to  claim 22  where the polymer or large molecule is immobile within the electrode. 
     
     
         24 . An electrode according to  claim 22  where the polymer or large molecule is removed after formation of the electrode. 
     
     
         25 . An electrode according to  claim 22  where the polymer or large molecule is an ionic liquid, a polyionic liquid polymer, an ionomer or an equivalent binder. 
     
     
         26 . An electrode according to  claim 2  where the mesoporous volume is produced from the assembly of graphene sheets containing defects and distortions. 
     
     
         27 . An electrode according to  claim 2  where the mesoporous volume is produced from the assembly of graphene agglomerates containing graphene containing defects and distortions. 
     
     
         28 . An electrode according to  claim 27  where said defects and distortions are curvatures of the graphene sheet or wrinkles formed by drying an aerosol of graphene dispersion. 
     
     
         29 . An electrode according to  claim 27  where the defects and distortions are curvatures of the graphene sheet or wrinkles formed by quenching graphene from high temperature. 
     
     
         30 . An electrode according to  claim 27  where the defects and distortions are curvatures of the graphene sheet or wrinkles formed by thermal reduction of graphene oxide to graphene. 
     
     
         31 . An electrode according to  claim 27  where the defects and distortions are wrinkles and bubbles formed by expansion of the graphene interlayer spaces due to volatilisation of species incorporated between the sheets. 
     
     
         32 . A capacitive electrode for ionic separation formed on a substrate including a graphene foil, a graphene film or a graphene coating. 
     
     
         33 . A capacitive electrode according to  claim 32  where the graphene foil is electrically conductive, flexible and mechanically robust. 
     
     
         34 . A capacitive electrode according to  claim 33  where the graphene foil provides all of the electrical pathway in the substrate. 
     
     
         35 . A capacitive electrode according to  claim 32  where the graphene is a coating on the surface of a metal foil, a metal film, a metal mesh, a metal cloth or a metal fibre. 
     
     
         36 . A capacitive electrode according to  claim 35  where the graphene coating protects the metal surface from corrosion. 
     
     
         37 . A capacitive electrode according to  claim 35  where the graphene coating provides an electrical connection between the active electrode material and the metal surface. 
     
     
         38 . A capacitive electrode according to  claim 35  where said conductive fibres or mesh are embedded in, or in contact with, said graphene coating.