Porous solid oxide fuel cell anode with nanoporous surface and process for fabrication

Abstract

Electrochemical devices including solid oxide fuel cells (SOFCs) or thin film solid oxide fuel cells (TFSOFCs) having a porous metallic anode with nanoporous surface structure enabling the deposition of a dense, impermeable thin film electrolyte layer on the porous anode. Fabricating methods include forming a mixture of nanopowder metallic agents and nanopowder proppant that are sintered, smoothed and etched to form the nanoporous surface structure.

We claim: 
     
         1 . A method comprising the step:
 combining a metallic nanopowder and a proppant nanopowder to form a nanopowder mixture, pressing the nanopowder mixture into a pressed shape having a least one flat surface, and   heating the pressed shape at an elevated temperature to form a sintered slab.   
     
     
         2 . The method of  claim 1 , further comprising:
 polishing the flat surface of the sintered slab to a smooth surface having a roughness of less than or equal to about 50 nm.   
     
     
         3 . The method of  claim 2 , wherein the polishing step comprises mechanical polishing. 
     
     
         4 . The method of  claim 2 , wherein the polishing step comprises chemical polishing. 
     
     
         5 . The method of  claim 2 , wherein the polishing step comprises chemical-mechanical polishing (CMP). 
     
     
         6 . The method of  claim 2 , further comprising:
 an additional step of pore opening to improve the opening of surface nanopores having a largest dimension of between about 10 mm and about 1000 nm.   
     
     
         7 . The method of  claim 6 , wherein the additional step comprises ion etching, chemical etching or other technique for opening surface nanopores. 
     
     
         8 . The method of  claim 1 , further comprising:
 depositing onto the smoothed surface an oxide electrolyte to form a continuous, dense, and electrically insulating thin film layer thereon.   
     
     
         9 . The method of  claim 8 , wherein the depositing step comprises physical deposition, chemical vapor deposition, other thin film deposition process or mixtures and combinations thereof. 
     
     
         10 . The method of  claim 1 , further comprising the step of:
 after the depositing step, depositing a cathode layer on the insulating thin film layer to form a thin film solid oxide fuel cell electrical element.   
     
     
         11 . The method of  claim 10 , wherein the metallic nanopowder comprises particles having particle sizes between about 10 nm and 500 nm and the proppant nanopowder comprises particles having sizes between from 10 nm and 500 nm.