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Published November 8, 2006 | public
Journal Article

High Power Density Single Chamber Fuel Cells Operated on Methane

Abstract

Single-chamber solid oxide fuel cells (SC-SOFCs) incorporating thin-film Sm_(0.15)Ce_(0.85)O_(1.925) (SDC) as the electrolyte, thick Ni + SDC as the (supporting) anode and SDC + BSCF (Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ)) as the cathode were operated in a mixture of methane, oxygen and helium at furnace temperatures of 500–650 °C. Because of the exothermic nature of the oxidation reactions that occur at the anode, the cell temperature was as much as 150 °C greater than the furnace temperature. Overall, the open circuit voltage was only slightly sensitive to temperature and gas composition, varying from ∼0.70 to ∼0.78 V over the range of conditions explored. In contrast, the power density strongly increased with temperature and broadly peaked at a methane to oxygen ratio of ∼1:1. At a furnace temperature of 650 °C (cell temperature ∼790 °C), a peak power density of 760 mW cm^(−2) was attained using a mixed gas with methane, oxygen and helium flow rates of 87, 80 and 320 mL min^(−1) [STP], respectively. This level of power output is the highest reported in the literature for single chamber fuel cells and reflects the exceptionally high activity of the BSCF cathode for oxygen electro-reduction and its low activity for methane oxidation.

Additional Information

© 2006 Elsevier. Received 26 May 2006. Revised 30 June 2006. Accepted 3 July 2006. Available online 22 August 2006. The authors gratefully acknowledge Dr. Shaomin Liu (formerly of Caltech) for providing a portion of the BSCF powder used in this work, Dr. Ma Chi for assistance with acquisition of scanning electron microscopy images and Prof. Janet Hering for providing access to surface area analysis instrumentation. This work was funded by the Defense Advanced Research Projects Agency, Microsystems Technology Office. Additional support was provided by the National Science Foundation through the Caltech Center for the Science and Engineering of Materials.

Additional details

Created:
August 22, 2023
Modified:
October 25, 2023