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RESEARCH PRODUCT

Energy Conversion: Solid Oxide Fuel Cells: First-Principles Modeling of Elementary Processes

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Fuel cells are electrochemical devices that directly transform the chemical free energy of combustion (e.g., H2 + O2 and CHx + O2) into electrical energy. The avoidance of a thermal detour guarantees high theoretical efficiency. As far as the temperature regimes are concerned, we distinguish between high temperature ceramic fuel cells, intermediate-temperature fuel cells, and low temperature (i.e., only slightly above room temperature) fuel cells. The high temperature fuel cells are usually based on oxide components (ternary transition metal oxides as cathodes, Ni or Cu cermets as anodes, and acceptor-doped zirconia or ceria as electrolytes). The high temperature necessary for ion conduction (though giving rise to problems concerning materials durability and compatibility) is favorable for the electrode reaction kinetics and additionally allows direct electrochemical conversion of hydrocarbons. Low temperature fuel cells basically rely on the reaction between H2 and O2 and typically use polymeric proton conductors (ionomers) ([1] and references cited there). A major materials challenge is the selection of the