Fuel cell electrolyte membrane with acidic polymer

Abstract

An electrolyte membrane is formed by an acidic polymer and a low-volatility acid that is fluorinated, substantially free of basic groups, and is either oligomeric or non-polymeric.

1 . An electrolyte membrane comprising:
 a polysulfonated fluoropolymer; and   a fluorinated acid selected from the group consisting of sulfonic acids, imide acids, and combinations thereof.   
     
     
         2 . The electrolyte membrane of  claim 1 , wherein the acidic polymer comprises a highly fluorinated backbone and pendant groups, wherein the pendent groups are selected from the group consisting of —OCF 2 CF(CF 3 )OCF 2 CF 2 SO 3 Y, —O(CF 2 ) 4 SO 3 Y, and combinations thereof, wherein Y is selected from the group consisting of a hydrogen ion, a cation, and combinations thereof. 
     
     
         3 . The electrolyte membrane of  claim 1 , wherein the fluorinated acid comprises a bis-acid. 
     
     
         4 . The electrolyte membrane of  claim 1 , wherein the electrolyte membrane is substantially free of phosphoric acid. 
     
     
         5 . The electrolyte membrane of  claim 1 , further comprising inorganic additives. 
     
     
         6 . The electrolyte membrane of  claim 1 , further comprising a reinforcement matrix.