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

Improves Fuel Cell Power Density to Increase Rate of Energy Output

This fuel-cell technology improves power density and efficiency. Fuel cells combine oxygen and fuel to chemically generate electricity without combustion. The global fuel cell market could grow to $6 billion by 2024. Of the many existing fuel-cell technologies, solid-oxide fuel cells are distinctly able to use fuels other than hydrogen. When combined with a liquid tin anode, it forms 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, while tolerating impurities such as sulfur. However, this type of fuel cell typically uses a thick electrolyte portion that reduces power density.

Researchers at the University of Florida have developed a fuel-cell anode comprising 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.

Application

A fuel-cell anode made up of a porous ceramic molten metal composite of a metal or metal alloy that increases power generation efficiency

Advantages

• Uses a thinner and more conductive electrolyte, increasing power density and efficiency
• Combines with liquid tin anode technology, allowing the solid oxide fuel cell to use a wide variety of fuels in gas, liquid, or solid form

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 their 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 in generating the electrical power resulting from the chemical reaction produced 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.