A solid oxide fuel cell using an exothermic reaction as the heat source

Performance of a single-chamber solid oxide fuel cell was evaluated using a 0.15 mm thick Sm-doped ceria (SDC) electrolyte together with a 30 wt % SDC-Ni anode and a Sm0.5Sr0.5CoO3 cathode at heating temperatures below 500 degreesC in a flowing mixture of butane and air. A large quantity of reaction heat, which was evolved by the partial oxidation of butane by oxygen at the anode, caused a temperature rise of more than 100 degreesC at the anode, followed by thermal conduction to the cathode through the electrolyte. Simultaneously, the cell generated a large electromotive force of ca. 900 mV between the two electrodes. The resulting peak power density reached 245, 180, 105, and 38 mW cm(-2) at heating temperatures of 450, 400, 350, and 300 degreesC, respectively. The comparison of the butane fuel with the other hydrocarbon fuels showed that the fuel cell performance became enhanced, especially at reducing temperatures, as the carbon number of the hydrocarbon increased, and the chain structure was branched. (C) 2001 The Electrochemical Society.