Electrochemical cell that operates efficiently with fluctuating currents

Abstract

Disclosed are electrochemical cells and methods of use or operation, in which one or more gas-producing electrodes operate in a manner that is bubble-free or substantially bubble-free. Disclosed are electrochemical cells and methods of operation or use under conditions of intermittent and/or fluctuating currents. In one aspect there is provided a method for operating an electrochemical cell, and an electrochemical cell, wherein the electrochemical cell comprises: a gas-producing electrode; a counter electrode, the gas-producing electrode and the counter electrode being separated by an electrolyte. Preferably there is also provided one or more void volumes. The method comprises: supplying an intermittent and/or fluctuating current to at least the gas-producing electrode; and producing a gas at the gas-producing electrode as a result of an electrochemical reaction. Preferably the gas is received by the one or more void volumes.

1 . A method for operating an electrochemical cell, wherein the electrochemical cell comprises:
 one or more void volumes;   a gas-producing electrode; and,   a counter electrode, the gas-producing electrode and the counter electrode being separated by an electrolyte;   wherein the method comprises:
 supplying an intermittent or fluctuating current to at least the gas-producing electrode; and 
 producing a gas at the gas-producing electrode as a result of an electrochemical reaction, wherein the gas is received by the one or more void volumes. 
   
     
     
         2 . The method of  claim 1 , wherein the electrolyte is a liquid electrolyte. 
     
     
         3 . The method of  claim 1 , wherein the electrolyte is a gel electrolyte. 
     
     
         4 . The method of any one of  claims 1  to  3 , wherein substantially no bubbles of the gas are formed at the gas-producing electrode, or bubbles of the gas are not formed at the gas-producing electrode. 
     
     
         5 . The method of any one of  claims 1  to  4 , wherein the current is unconditioned. 
     
     
         6 . The method of any one of  claims 1  to  5 , wherein the current is derived from excess electrical energy from an electrical grid. 
     
     
         7 . The method of any one of  claims 1  to  6 , wherein there is no ion exchange membrane positioned between the gas-producing electrode and the counter electrode. 
     
     
         8 . The method of any one of  claims 1  to  6 , wherein there is no diaphragm positioned between the gas-producing electrode and the counter electrode. 
     
     
         9 . The method of any one of  claims 1  to  8 , wherein the gas-producing electrode is a gas diffusion electrode. 
     
     
         10 . The method of any one of  claims 1  to  9 , wherein the counter electrode is a gas diffusion electrode. 
     
     
         11 . The method of any one of  claims 1  to  10 , wherein the counter electrode produces a second gas, and substantially no bubbles of the second gas are formed at the counter electrode, or bubbles of the second gas are not formed at the counter electrode. 
     
     
         12 . The method of  claim 11 , wherein the second gas is received by separate one or more void volumes. 
     
     
         13 . The method of any one of  claims 1  to  12 , wherein the current fluctuates by more than double the current. 
     
     
         14 . The method of any one of  claims 1  to  13 , wherein the current fluctuates by:
 more than triple the current, 
 more than four-fold the current, 
 more than five-fold the current, 
 more than six-fold the current, 
 more than eight-fold the current, 
 more than ten-fold the current, 
 more than twelve-fold the current, 
 more than fifteen-fold the current, 
 more than twenty-fold the current, or 
 more than twenty-five-fold the current. 
 
     
     
         15 . The method of any one of  claims 1  to  14 , wherein the one or more void volumes are positioned within, partially within or adjacent to the electrolyte. 
     
     
         16 . The method of any one of  claims 1  to  14 , wherein the one or more void volumes are positioned at or adjacent to the gas-producing electrode. 
     
     
         17 . An electrochemical cell for producing a gas from an electrochemical reaction, comprising:
 one or more void volumes;   a gas-producing electrode;   a counter electrode; and,   an electrolyte between the gas-producing electrode and the counter electrode;   wherein in operation an intermittent or fluctuating current is supplied to at least the gas-producing electrode; and   wherein the gas is produced at the gas-producing electrode and is received by the one or more void volumes.   
     
     
         18 . The electrochemical cell of  claim 17 , wherein the electrolyte is a liquid electrolyte or a gel electrolyte. 
     
     
         19 . The electrochemical cell of  claim 17  or  18 , wherein substantially no bubbles of the gas are formed at the gas-producing electrode, or bubbles of the gas are not formed at the gas-producing electrode. 
     
     
         20 . The electrochemical cell of any one of  claims 17  to  19 , wherein the one or more void volumes form a gaseous conduit to transport the gas. 
     
     
         21 . The electrochemical cell of any one of  claims 17  to  20 , wherein the one or more void volumes allow the gas if formed rapidly in the electrolyte to escape from the electrochemical cell. 
     
     
         22 . The electrochemical cell of any one of  claims 17  to  21 , wherein there is no diaphragm or ion exchange membrane positioned between the gas-producing electrode and the counter electrode. 
     
     
         23 . The electrochemical cell of any one of  claims 17  to  22 , wherein the gas-producing electrode is a gas diffusion electrode. 
     
     
         24 . The electrochemical cell of any one of  claims 17  to  23 , wherein the counter electrode is a gas diffusion electrode. 
     
     
         25 . The electrochemical cell of any one of  claims 17  to  24 , wherein the one or more void volumes are positioned within, partially within or adjacent to the electrolyte. 
     
     
         26 . The electrochemical cell of any one of  claims 17  to  24 , wherein the one or more void volumes are positioned at or adjacent to the gas-producing electrode. 
     
     
         27 . The electrochemical cell of any one of  claims 17  to  24 , wherein the one or more void volumes are positioned:
 outside of the electrical conduction pathway between the gas-producing electrode and the counter electrode, or 
 peripheral to or adjacent to the electrical conduction pathway between the gas-producing electrode and the counter electrode. 
 
     
     
         28 . The electrochemical cell of any one of  claims 17  to  24 , wherein the one or more void volumes are positioned between the gas-producing electrode and the counter electrode and within the electrical conduction pathway. 
     
     
         29 . The electrochemical cell of any one of  claims 17  to  24 , wherein the one or more void volumes have a small cross-sectional area relative to the electrical conduction pathway between the gas-producing electrode and the counter electrode. 
     
     
         30 . The electrochemical cell of any one of  claims 17  to  24 , wherein the one or more void volumes are positioned perpendicular to one or both of the gas-producing electrode and the counter electrode. 
     
     
         31 . The method of any one of  claims 17  to  30 , wherein the current is produced by an intermittent or fluctuating power source. 
     
     
         32 . The method of  claim 31 , wherein the power source is a solar-generator or a wind-generator.