Gas permeable electrode and method of manufacture

Abstract

A gas permeable or breathable electrode and method of manufacture thereof. In one example there is an electrolytic cell having an electrode comprising a porous material, wherein gas produced at the electrode diffuses out of the cell via the porous material. In operation the gas is produced at the at least one electrode without substantial bubble formation. In another example there is an electrode having a porous conducting material with a hydrophobic layer or coating applied to a side of the porous conducting material. A catalyst may be applied to another side. The gas permeable or breathable electrode can be used in an electrolytic cell, electrochemical cell, battery and/or fuel cell. Gas produced at the electrode diffuses out of a cell via at least part of the electrode, separating the gas from the reaction at the electrode.

1 - 30 . (canceled) 
     
     
         31 . A gas permeable electrode comprising:
 a porous conducting material; and   a hydrophobic layer.   
     
     
         32 . The gas permeable electrode according to  claim 31 , wherein the hydrophobic layer is a coating on at least part of a first side of the porous conducting material. 
     
     
         33 . The gas permeable electrode according to  claim 31 , including a catalyst applied to at least a portion of the porous conducting material. 
     
     
         34 . The gas permeable electrode according to  claim 33 , wherein the catalyst is applied to at least part of a second side of the porous conducting material. 
     
     
         35 . The gas permeable electrode according to  claim 31 , wherein the porous conducting material is gas permeable and electrolyte impermeable. 
     
     
         36 . The gas permeable electrode according to  claim 34 , wherein the hydrophobic layer does not cover or overlay the second side of the porous conducting material. 
     
     
         37 . The gas permeable electrode according to  claim 31 , wherein the porous conducting material is at least partially formed of a material selected from the group consisting of conducting carbon, carbon fibre, non-woven carbon fibre, carbon nanotube felt, graphene and carbon nanotubules. 
     
     
         38 . The gas permeable electrode according to  claim 31 , wherein the porous conducting material is at least partially formed of a material selected from the group consisting of Ni, Ti, Cr, Cu, Au or Ag. 
     
     
         39 . The gas permeable electrode according to  claim 31 , wherein the porous conductive material is a woven or non-woven mesh, grid, net, lattice or web. 
     
     
         40 . The gas permeable electrode according to  claim 31 , wherein the porous conductive material is formed of a conductive material coated onto fibres, strands or fabric, which are then woven to form the porous conducting material. 
     
     
         41 . The gas permeable electrode according to  claim 31 , wherein the porous conductive material has a resistance less than 3 Ω/m 2 . 
     
     
         42 . The gas permeable electrode according to  claim 31 , wherein the porous conductive material has a pore size less than 50 μm. 
     
     
         43 . The gas permeable electrode according to  claim 31 , wherein the hydrophobic layer is a polymer material. 
     
     
         44 . The gas permeable electrode according to  claim 31 , wherein the hydrophobic layer is formed from at least one fluorinated hydrocarbon precursor. 
     
     
         45 . The gas permeable electrode according to  claim 31 , wherein the hydrophobic layer is poly-perfluoro(methyldecalin). 
     
     
         46 . The gas permeable electrode according to  claim 33 , wherein the gas permeable electrode is a ‘hydrophobic coating’-‘porous conducting material’-‘catalyst’ combination selected from the group consisting of poly(perfluoro(methyldecalin))-carbon fibre-poly(3,4-ethylenedioxy thiophene), poly(perfluoro(methyldecalin))-copper-platinum, poly(perfluoro(methyldeclain))-nickel and poly(perfluoro(methyldecalin))-nickel-platinum. 
     
     
         47 . A method of manufacturing a gas permeable electrode, comprising the steps of:
 providing a porous conducting material; and   associating a hydrophobic layer with the porous conducting material.   
     
     
         48 . The method according to  claim 47 , wherein the hydrophobic layer is applied as a coating to at least part of a first side of the porous conducting material. 
     
     
         49 . The method according to  claim 47 , further including a step of pre-treating a surface of the porous conducting material to remove oxide prior to associating the hydrophobic layer. 
     
     
         50 . The method according to  claim 47 , further including a step of applying a catalyst to at least part of a second side of the porous conducting material. 
     
     
         51 . The method according to  claim 50 , wherein the hydrophobic layer does not cover or overlay the second side of the porous conducting material. 
     
     
         52 . An electrolytic cell comprising:
 at least one gas permeable electrode comprising a porous conducting material and a hydrophobic layer associated with at least part of a first side of the porous conducting material; and   an electrolyte;   
       wherein, the first side of the porous conducting material faces away from the electrolyte, and in operation, gas is produced at the at least one gas permeable electrode without substantial bubble formation and diffuses out of the cell via the at least one gas permeable electrode. 
     
     
         53 . The electrolytic cell according to  claim 52 , in operation used for reduction of N 2 , 2NO 2   −  or CO 2 ; or oxidation of a halide, H 2 O 2  or NO 2   − . 
     
     
         54 . The electrolytic cell according to  claim 52 , for use in a battery or fuel cell. 
     
     
         55 . The electrolytic cell according to  claim 52 , wherein the electrolytic cell is a water splitting cell and the electrolyte is at least partially water. 
     
     
         56 . The electrolytic cell according to  claim 55 , wherein the at least one gas permeable electrode is a cathode, and in operation H 2  gas is produced at the cathode and diffuses out of the cell via the porous conductive material without substantial bubble formation. 
     
     
         57 . The electrolytic cell according to  claim 55 , wherein the at least one gas permeable electrode is an anode, and in operation O 2  gas is produced at the anode and diffuses out of the cell via the porous conductive material without substantial bubble formation. 
     
     
         58 . A method of using the electrolytic cell according to  claim 52 , the method comprising the steps of:
 immersing the at least one gas permeable electrode in the electrolyte; and   passing a current through the at least one gas permeable electrode.