Cathode for fuel cells and method of manufacturing membrane electrode assembly having the same

Abstract

A cathode for fuel cells includes a carbon support, a platinum catalyst supported on the carbon support and an ionomer surrounding the carbon support and the platinum catalyst, wherein the ionomer is removed from the surface of the platinum catalyst. The cathode for fuel cells has a structure in which an ionomer film coating the surface of the platinum catalyst and thus acting as oxygen transfer resistance is removed from the surface of the platinum catalyst and, thus, mass transfer resistance (oxygen diffusion resistance) may be reduced and performance of a fuel cell may be improved. Further, the cathode having a low amount of platinum used due to improvement in platinum utilization may effectively execute oxygen transfer and thus increase the amount of platinum participating in catalysis, as compared to conventional cathodes.

What is claimed is: 
     
         1 . A cathode for fuel cells comprising:
 a carbon support;   a platinum catalyst supported on the carbon support; and   an ionomer surrounding the carbon support and the platinum catalyst,   wherein the ionomer is removed from a surface of the platinum catalyst.   
     
     
         2 . The cathode for fuel cells of  claim 1 , wherein the carbon support is a highly crystalline carbon support having a high degree of graphitization. 
     
     
         3 . The cathode for fuel cells of  claim 1 , wherein the carbon support and the platinum catalyst are surrounded with the ionomer such that only the surface of the platinum catalyst is not coated with the ionomer. 
     
     
         4 . A membrane electrode assembly for fuel cells comprising the cathode of  claim 1 . 
     
     
         5 . A fuel cell comprising the membrane electrode assembly of  claim 4 .