Solid Oxide Fuel Cells for Direct Oxidation of Liquid Hydrocarbon Fuels in Automotive Auxiliary Power Units: Sulfur Tolerance and Operation on Gasoline

To be practical, auxiliary power units (APUs) should operate on the same fuels that the internal combustion engine (ICE) uses for vehicle propulsion. Solid oxide fuel cells (SOFCs) have previously been shown to be able to convert the chemical energy of certain room-temperature-liquid hydrocarbon fuels (toluene and synthetic diesel fuel) to electricity by direct oxidation. Because such SOFCs operate without reformers, the systems based on these SOFCs are expected to be compact. To work with existing infrastructure fuels, the cells must be able to tolerate typical contaminants such as sulfur that are found in the everyday fuels. In this paper, we report on recent laboratory results that show direct oxidation SOFCs with ceria-copper anodes can provide at least 2 hours operation in the presence of 200 ppm sulfur in the fuel. Also, a laboratory cell has been run for 12 hours on regular unleaded gasoline.