Electrochemical half-cell

Abstract

The present invention describes an electrochemical half-cell, comprising a gas space, an electrolyte space and a gas diffusion electrode in the form of a cathode or anode. The gas diffusion electrode separates the gas space from the electrolyte space and comprises an electrically conductive substrate and an electrochemically active coating. The gas diffusion electrode includes a coating-free edge region and is connected to a support structure in the coating-free edge region via an electrically conductive plate, which covers at least the coating-free edge region as well as a coated edge region.

1 . An electrochemical half-cell, comprising a gas space, an electrolyte space and a gas diffusion electrode in the form of a cathode or anode, which separates the gas space from the electrolyte space and comprises at least an electrically conductive substrate and an electrochemically active coating, the gas diffusion electrode having a coating-free edge region and is capable of being connected to a support structure, 
 wherein when the gas diffusion electrode is connected to the support structure, said connection can be made in the coating-free edge region with an electrically conductive plate, which covers at least the coating-free edge region and an edge region of the electrochemically active coating.    
   
   
       2 . An electrochemical half-cell according to  claim 1 , wherein the coating-free edge region measures from about 2 to about 10 mm.  
   
   
       3 . An electrochemical half-cell according to  claim 1 , wherein the edge region of the electrochemically active coating, which is covered by the electrically conductive plate, measures from about 2 to about 8 mm.  
   
   
       4 . An electrochemical half-cell according to  claim 1 , wherein in the gas diffusion electrode is connected to the support structure via the electrically conductive plate by a weld.  
   
   
       5 . An electrochemical half-cell according to  claim 1 , wherein the electrically conductive plate has a thickness of from about 0.05 to about 2 mm.  
   
   
       6 . An electrochemical half-cell according to  claim 1 , wherein the electrically conductive plate comprises metal.  
   
   
       7 . An electrochemical half-cell according to  claim 1 , further comprising a seal provided in a vicinity of the surface by which the gas diffusion electrode rests on the support structure.  
   
   
       8 . An electrochemical half-cell according to  claim 1 , further comprising a surfactant solution applied in the edge region of the coating.  
   
   
       9 . An electrochemical half-cell according to  claim 6 , wherein said conductive plate comprises nickel.  
   
   
       10 . An electrochemical half-cell comprising a support, a gas diffusion electrode electrically connected to the support via an electrically conductive plate, wherein gas space in said half cell is sealed off from electrolyte space in said half cell so that substantially little electrolyte can enter the gas space and substantially little gas can enter the electrolyte space.  
   
   
       11 . An electrochemical half cell comprising a support, a gas diffusion electrode comprising a substrate having an electrochemically active coating on a portion thereof so as to form at least one coated region and at least one uncoated region, said gas diffusion electrode being connected to said support via an electrically conductive plate, said plate contacting said substrate in both a coated region and an uncoated region thereof.  
   
   
       12 . An electrochemical half cell of  claim 11 , wherein said electrochemically active coating comprises silver and PTFE.  
   
   
       13 . An electrochemical half cell of  claim 11 , wherein said substrate of said electrode further includes a gas diffusion layer.  
   
   
       14 . An electrochemical half cell of  claim 12 , further comprising a PTFE seal between the support and the gas diffusion electrode.  
   
   
       15 . An electrochemical half cell of  claim 11 , wherein said coating is at least partially hydrophilic.  
   
   
       16 . A method for reducing the electrochemically active area lost due to installation of a gas diffusion electrode in a half cell, said method comprising sealing off gas space from electrolyte space in said half cell using an electrically conductive plate.  
   
   
       17 . A method according to  claim 16 , wherein said gas diffusion electrode includes at least one coated region and at least one uncoated region and said method further includes contacting said plate in both an uncoated and coated region of said electrode.  
   
   
       18 . A method installing a gas diffusion electrode in a half cell comprising 
 Removing a portion of electrochemically active coating from said electrode to form at least one coated and at least one uncoated region thereof    Placing said electrode on a support of said half cell, wherein said electrode is adjacent to said support in both a coated and an uncoated region thereof.    
   
   
       19 . A method of  claim 18 , further comprising placing an electrically conductive plate between said support and said electrode.  
   
   
       20 . A method of  claim 18 , further comprising placing a seal between the support and the electrode.  
   
   
       21 . A method of  claim 18 , wherein said support comprises nickel.  
   
   
       22 . An electrochemical half cell according to  claim 11 , wherein said support comprises nickel.