Electrochemical half-cell

Abstract

The invention describes an electrochemical half-cell, in particular for the electrolysis of aqueous solutions of hydrogen chloride, at least comprising a gas space, the gas space having a gas feed and a gas discharge as well as a liquid outlet, and a gas diffusion electrode which rests on an electrically conductive current distributor and makes an electrically conductive contact with the current distributor, the current distributor having a free area in the range from 5 to 65%, preferably from 10 to 60%, particularly preferably from 15 to 50%, based on the total area of the current distributor, and a thickness of from 0.3 mm to 5 mm, preferably from 0.35 to 0.6 mm.

1 . An electrochemical half-cell, suitable for the electrolysis of aqueous solutions of hydrogen chloride, said electrochemical half-cell comprising: 
 at least one gas space, the gas space having a gas feed and a gas discharge as well as a liquid outlet , and    a gas diffusion electrode which rests on an electrically conductive current distributor and makes electrically conductive contact with the current distributor, wherein the current distributor has a free area in the range from 5 to 65%, based on the total area of the current distributor, and a thickness of from 0.3 mm to 5 mm.    
     
     
         2 . An electrochemical half-cell according to  claim 1  wherein the current distributor has a free area from 10 to 60% based on the total area of the current distributor.  
     
     
         3 . An electrochemical half-cell according to  claim 1 , wherein the current distributor has a free area from 15 to 50%, based on the total area of the current distributor.  
     
     
         4 . An electrochemical half-cell according to  claim 1 , wherein the current distributor has a thickness from 0.35 to 2 mm.  
     
     
         5 . An electrochemical half-cell according to  claim 1 , wherein the current distributor at least comprises an expanded metal, net, woven fabric, foam, nonwoven, slotted metal sheet or perforated plate.  
     
     
         6 . An electrochemical half-cell according to  claim 1 , wherein the current distributor comprises an expanded metal having a mesh length in the range from 4 to 8 mm, a mesh width in the range from 3 to 5 mm, a web width in the range from 0.4 to 1.8 mm and a web thickness in the range from 0.35 to 2 mm.  
     
     
         7 . An electrochemical half-cell according to  claim 1 , wherein the current distributor rests on an electrically conductive base support and has an electrically conductive connection to the base support, the base support at least comprising an expanded metal, net, woven fabric, foam, nonwoven, slotted metal sheet or perforated plate.  
     
     
         8 . An electrochemical half-cell according to  claim 7 , wherein the base support comprises an expanded metal having a mesh length of from 10 to 40 mm, a mesh width of from 5 to 15 mm, a web width of from 2 to 5 mm and a web thickness of from 0.8 to 4 mm.  
     
     
         9 . An electrochemical half-cell according to  claim 7 , wherein the base support comprises a net having a thickness of from 1 to 4 mm and a mesh width of from 7 to 25 mm.  
     
     
         10 . An electrochemical half-cell according to  claim 7 , wherein the base support comprises a perforated metal sheet or slotted metal sheet having a free area of not more than 70% and a thickness of from 1 to 4 mm.  
     
     
         11 . An electrochemical half-cell according to  claim 1 , wherein the current distributor comprises at least one of (i) titanium or (ii) a noble metal-stabilized titanium, and said current distributor is further optionally provided with a noble metal oxide coating.  
     
     
         12 . An electrochemical half-cell according to  claim 1 , wherein the current distributor comprises expanded metal which has been rolled flat.