Fuel cell electrode assemblies

Abstract

Fuel cell membrane electrode assemblies having at least two solution cast films, preferably in combination with a perimeter sealing material between the solution cast films.

I claim:  
     
         1 . A membrane electrode assembly consisting essentially of a central layer of ionomer material comprising at least two solution-cast ionomer components; and a catalyst layer adjacent to each side of the central layer.  
     
     
         2 . A membrane electrode assembly of  claim 1  wherein the assembly is prepared by 
 a. applying a catalyst slurry onto each of a first and a second removable decal;  
 b. drying each catalyst slurry to form a dried catalyst layer;  
 c. applying at least one ionomer solution layer on each resulting dried catalyst layer;  
 d. drying and at least partly curing each of the resulting layers of at least one ionomer solution;  
 e. bringing the ionomer layers on each of the first and second decal assemblies into contact to join the ionomer layers; and  
 f. removing the decals from the resulting assembly.  
 
     
     
         3 . A membrane electrode assembly of  claim 1  wherein the assembly is prepared by 
 a. applying a catalyst slurry onto a first decal;  
 b. drying the catalyst slurry;  
 c. applying a solution of at least one ionomer to a second decal;  
 d. dying and at least partly curing the resulting applied ionomer solution;  
 e. joining the two decal assemblies with the ionomer and catalyst layers in contact with each other; and  
 f. removing the decal from the ionomer layer to form a first membrane electrode assembly component;  
 g. repeating steps (a) to (f) to form a second membrane electrode assembly component, and combining the resulting two membrane electrode components by bringing the ionomer layers of each component into contact to join the ionomer layers; and removing the decals from the resulting assembly.  
 
     
     
         4 . A membrane electrode assembly of  claim 1  further comprising a perimeter sealing material between the at least two solution-cast ionomer components, the sealing material having a solid perimeter and a central portion having at least one perforation formed therein.  
     
     
         5 . A membrane electrode assembly of  claim 4  wherein the sealing material consists essentially of polyimide.  
     
     
         6 . A membrane electrode assembly of  claim 4  having a plurality of perforations formed in the central portion of the sealing material.  
     
     
         7 . A membrane electrode assembly of  claim 6  wherein the perforations in the central portion of the sealing material have a diameter of about from 3 to 10 mils.  
     
     
         8 . A membrane electrode assembly of  claim 4  wherein the thickness of the sealing material is about from 10 to 30 microns.  
     
     
         9 . A membrane electrode assembly of  claim 4  wherein the perimeter sealing material has a thickness of about from 10 to 30 microns.