Solid-Oxide Fuel Cell Anode With Greater Fuel Flexibility and More Efficient Power Generation


The University of Florida is seeking companies interested in commercializing fuel-cell technology with improved range of use. Fuel cells combine oxygen and fuel to chemically generate electricity without combustion. The domestic market for this innovative energy source could grow to $975 million by the year 2012 according to some studies. Of the many existing fuel-cell technologies solid-oxide fuel cells have the distinct advantage of being able to use fuels other than hydrogen allowing for greater flexibility. One of the major components of a fuel cell is called the anode where oxygen ions come into contact with the fuel used by the cell. Different substances can be used for this anode but one that has particular benefits including tolerance to impurities is the liquid tin anode. The combination of the two technologies is known as a liquid tin anode solid-oxide fuel cell (LTA-SOFC). This kind of fuel cell marries the efficiency and reliability of conventional solid-oxide fuel cells with an expanded range of potential fuels including gaseous liquid and solid fuels and tolerates impurities such as sulfur. However this type of fuel cell typically uses a thick electrolyte portion (yttria-stabilized zirconium oxide) that reduces power density. University of Florida researchers used a fuel-cell anode comprised of a porous ceramic molten metal composite that can be employed in a solid-oxide fuel cell with a thin ceramic electrolyte thus increasing efficiency in energy output and power density. Technology: Fuel cells create electricity without combustion by combining oxygen and various fuels. Solid-oxide fuel cells have the advantage of greater flexibility among the many types of fuel cells available. When used with liquid tin anodes these types of fuel cells take on other benefits including resistance to pollutants. However traditional liquid tin anodes have low power density and efficiency. University of Florida researchers have developed a fuel cell anode that resolves this problem while keeping the fuel flexibility benefits. These solid-oxide fuel cells employ a porous ceramic molten metal composite anode with a cathode an electrolyte in contact with the anode and the cathode and an electrical circuit connecting the anode and the cathode for use of the electrical power resulting from the chemical reaction generated by the oxidation of the fuel. The porous ceramic for example Gd-doped CeO2 (GDC) not only supports the molten metal for example tin but also complements the molten metal as it facilitates oxygen diffusion into the anode from the electrolyte and within the anode to an extent that is not possible in the liquid metal alone due to the low solubility of oxygen ion in the metal. Application: A fuel-cell anode made up of a porous ceramic molten metal composite of a metal or metal alloy for increased efficiency

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