Solid oxide fuel cell electrode systems and methods

Abstract

A solid oxide fuel cell (SOFC) interconnect comprises a metal sheet with an air side and a fuel side in accordance with an embodiment of the present invention. The metal sheet comprises a metallic composite having a matrix. The matrix comprises a first metal. The metal sheet also comprises a plurality of discontinuous, elongated, directional reinforcement wires. The reinforcement wires comprise a second metal that is immiscible in the first metal. An oxidation protection layer is disposed on the air side of the metal sheet.

1 . A solid oxide fuel cell (SOFC) interconnect comprising:
 a metal sheet comprising an air side and a fuel side, wherein the metal sheet comprises a metallic composite having a matrix comprising a first metal and a plurality of discontinuous, elongated, directional reinforcement wires, the reinforcement wires comprising a second metal, wherein the second metal is immiscible in the first metal; and   an oxidation protection layer disposed on the air side of the metal sheet.   
     
     
         2 . The SOFC interconnect of  claim 1 , wherein the oxidation protection layer comprises one of rhenium or iridium. 
     
     
         3 . The SOFC interconnect of  claim 1 , wherein the first metal comprises one of copper and silver and the second metal comprises molybdenum. 
     
     
         4 . The SOFC interconnect of  claim 1 , wherein the first metal comprises copper, the second metal comprises molybdenum and the metal sheet comprises molybdenum in a range from 20 to 38 volume percent. 
     
     
         5 . The SOFC interconnect of  claim 1 , wherein the reinforcement wires comprise pure molybdenum. 
     
     
         6 . The SOFC interconnect of  claim 1 , wherein the reinforcement wires comprise a molybdenum alloy comprising at least a small amount of one of titanium, zirconium or hafnium. 
     
     
         7 . The SOFC interconnect of  claim 1 , wherein the metal sheet comprises a 0/90 lay-up composite. 
     
     
         8 . The SOFC of  claim 1 , further comprising a first plurality of channels on the air side and a second plurality of channels on the fuel side. 
     
     
         9 . The SOFC interconnect of  claim 1 , further comprising;
 a first plurality of channels on the air side and a second plurality of channels on the fuel side; and   wherein the first metal comprises copper, the second metal comprises molybdenum, the metal sheet comprises molybdenum in a range from about 20 to about 38 volume percent of the metal sheet, and the oxidation layer comprises one of rhenium or iridium.   
     
     
         10 . A solid oxide fuel cell (SOFC) comprising:
 a plurality of individual fuel cells, each individual fuel cell comprising an anode layer, a cathode layer and an catalyst layer between the anode layer and the cathode layer;   a plurality of interconnects, wherein each interconnect separates adjacent individual fuel cells; and   wherein each one of the plurality of interconnects comprises a metal sheet comprising a metallic composite having a matrix comprising one of copper or silver and a plurality of discontinuous, elongated, directional reinforcement wires dispersed in the matrix, the reinforcement wires comprising molybdenum.   
     
     
         11 . The SOFC of  claim 10 , wherein the metallic composite comprises molybdenum in a range from 20 to 38 volume percent. 
     
     
         12 . The SOFC of  claim 10 , further comprising an oxidation protection layer disposed on an air side of the interconnect, wherein the air side of the interconnect is adjacent a cathode side of an adjacent one of the plurality of individual fuel cells. 
     
     
         13 . The SOFC of  claim 12 , wherein the oxidation protection layer comprises one of rhenium or iridium. 
     
     
         14 . The SOFC of  claim 10 , wherein the anode comprises Ni—PSV, the catalyst comprises PSZ and the cathode comprises LaCrO3. 
     
     
         15 . The SOFC of  claim 10 , wherein the reinforcement wires comprise a molybdenum alloy comprising small amounts of at least one of titanium (Ti), zirconium (Zr) or halfnium (Hf) 
     
     
         16 . A method of fabricating an interconnect for a solid oxide fuel cell (SOFC), comprising:
 melting a charge comprising copper and from 20 to 38 volume percent molybdenum and then cooling the melted charge to form an ingot comprising a metallic composite having a copper matrix and spheroids comprising molybdenum dispersed within the matrix;   forging the ingot followed by a first anneal to form a rough bar of metallic composite;   swaging the rough bar followed by a second anneal to form a plurality of rods suitable for drawing;   drawing the plurality of rods followed by a third anneal to form a plurality of wires of the metallic composite; and   bundling and canning the plurality of wires to form a sheet of the metallic composite, wherein the sheet is suitable for use as an interconnect in an SOFC.   
     
     
         17 . The method of  claim 16 , wherein the drawing and third anneal are repeated a plurality of times before bundling and canning. 
     
     
         18 . The method of  claim 16 , further comprising one of hot isotropically pressing (HIP) or co-rolling the bundled and canned plurality of wires to sinter the plurality of wires together to form a sheet or plate of metallic composite. 
     
     
         19 . The method of  claim 16 , wherein the plurality of rods are cold drawn and the third anneal is performed at a temperature of about 800° C. 
     
     
         20 . The method of  claim 16 , further comprising providing an oxidation protection layer to at least one side of the sheet by one of co-rolling the sheet with a thin foil of one of iridium or rhenium or by vapor depositing a layer of one of iridium or rhenium onto the at least one side of the sheet.