Solid Oxide Fuel Cells, Electrolyzers, and Sensors, and Methods of Making and Using the Same

Abstract

The present invention provides solid oxide fuel cells, solid oxide electrolyzer cells, solid oxide sensors, components of any of the foregoing, and methods of making and using the same. In some embodiments, a solid oxide fuel cell comprises an air electrode (or cathode), a fuel electrode (or anode), an electrolyte interposed between the air electrode and the fuel electrode, and at least one electrode-electrolyte transition layer. Other embodiments provide novel methods of producing nano-scale films and/or surface modifications comprising one or more metal oxides to form ultra-thin (yet fully-dense) electrolyte layers and electrode coatings. Such layers and coatings may provide greater ionic conductivity and increased operating efficiency, which may lead to lower manufacturing costs, less-expensive materials, lower operating temperatures, smaller-sized fuel cells, electrolyzer cells, and sensors, and a greater number of applications.

We claim: 
     
         1 . A sensor for at least one analyte, comprising at least one metal oxide made by a process comprising:
 applying at room temperature a liquid composition to a substrate that can be adapted to function as an electrode in the sensor,   the liquid composition comprising at least one metal compound, at least one nanoparticle having an average size of 50-100 nm, and optionally at least one carboxylic acid, and   converting at least some of the at least one metal compound to at least one metal oxide on the substrate; and   wherein the sensor is adapted to function by passing at least one ion through the at least one metal oxide to detect at least one analyte.   
     
     
         2 . The sensor of  claim 1 , wherein the at least one analyte is chosen from O 2 , CO, CO 2 , H 2 , NO x , SO x , H + , K + , Na + , and glucose. 
     
     
         3 . The sensor of  claim 1 , wherein the at least one analyte is oxygen. 
     
     
         4 . The sensor of  claim 1 , wherein the at least one metal compound comprises at least one zirconium compound and at least one yttrium compound. 
     
     
         5 . The sensor of  claim 1 , further comprising a transition layer between the substrate and the at least one metal oxide. 
     
     
         6 . The sensor of  claim 5 , wherein the transition layer has a thickness less than about 10 nm. 
     
     
         7 . The sensor of  claim 1 , wherein the substrate comprises at least one catalytic material. 
     
     
         8 . The sensor of  claim 7 , wherein the at least one catalytic material is chosen from platinum, palladium, rhodium, nickel, cerium, gold, silver, zinc, lead, ruthenium, rhenium, and combinations thereof. 
     
     
         9 . The sensor of  claim 1 , wherein the at least one metal oxide comprises a plurality of metal oxide layers on the substrate. 
     
     
         10 . The sensor of  claim 9 , wherein the plurality of metal oxide layers comprise at least one compositional gradient. 
     
     
         11 . The sensor of  claim 10 , wherein the at least one compositional gradient comprises substrate material, and the plurality of metal oxide layers comprise a greater concentration of substrate material in a region proximal to the substrate than in a region distal to the substrate. 
     
     
         12 . The sensor of  claim 1 , wherein the sensor is a lambda sensor. 
     
     
         13 . The sensor of  claim 1 , further comprising a second electrode separated from the substrate by the at least one metal oxide. 
     
     
         14 . The sensor of  claim 13 , wherein the second electrode comprises at least one catalytic material. 
     
     
         15 . The sensor of  claim 14 , wherein the at least one catalytic material is chosen from platinum, palladium, rhodium, nickel, cerium, gold, silver, zinc, lead, ruthenium, rhenium, and combinations thereof.