The performance of a single-chamber solid oxide fuel cell was studied using a ceria-based solid electrolyte at temperatures below 773 kelvin. Electromotive forces of ∼900 millivolts were generated from the cell in a flowing mixture of ethane or propane and air, where the solid electrolyte functioned as a purely ionic conductor. The electrode-reaction resistance was negligibly small in the total internal resistances of the cell. The resulting peak power density reached 403 and 101 milliwatts per square centimeter at 773 and 623 kelvin, respectively.

Ceramics were synthesized and their ionic conduction was investigated. These ceramics showed protonic and oxide ionic mixed conduction under fuel cell condition. While protonic conduction was predominant below 1027 K, oxide ionic conduction became significant as the temperature increased. Using these oxides as solid electrolyte, hydrogen‐air fuel cell could be constructed. exhibited the best cell performance among the electrolytes examined. The maximum short‐circuit current density was about 900 mA/cm² at 1273 K. The polarization at each electrode was low. Porous nickel could be used as anode material instead of expensive platinum and as cathode material.

The performance of a solid oxide fuel cell (SOFC) with the configuration, <mml:math display="inline"><mml:msub><mml:mo>H</mml:mo><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>,</mml:mo></mml:math>H2, 3 wt % Pd-loaded FeO|25 mol % <mml:math display="inline"><mml:msup><mml:mo>Y</mml:mo><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math>Y3+ -doped <mml:math display="inline"><mml:msub><mml:mi mathvariant="normal">BaCeO</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mo> </mml:mo><mml:mo stretchy="false">(</mml:mo><mml:mo>BCY</mml:mo><mml:mn>25</mml:mn><mml:mo stretchy="false">)</mml:mo><mml:mo>|</mml:mo><mml:msub><mml:mi mathvariant="normal">Ba</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Pr</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">CoO</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mo>,</mml:mo></mml:math>BaCeO3 (BCY25)|Ba0.5Pr0.5CoO3, air, was studied between 350 and 600°C. The BCY25 electrolyte showed higher ion conductivities than 8 mol % yttria-stabilized zirconia (YSZ) below 800°C and 20 mol % <mml:math display="inline"><mml:msup><mml:mi mathvariant="normal">Sm</mml:mi><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math>Sm3+ -doped ceria (SDC) below 600°C, thus having the smallest ohmic resistance loss during cell discharge below 600°C among the three electrolytes. The overpotentials of the Pd-loaded FeO anode and the <mml:math display="inline"><mml:msub><mml:mi mathvariant="normal">Ba</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Pr</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">CoO</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:math>Ba0.5Pr0.5CoO3 cathode at 600°C were 25 and 53 mV, respectively, at 200 mA cm⁻², which were less than one-fourth those of a Pt electrode. The resulting peak power density was higher than those obtained for two SOFCs using the YSZ and SDC electrolytes with a Ni-SDC anode and a <mml:math display="inline"><mml:msub><mml:mi mathvariant="normal">Sm</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Sr</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">CoO</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:math>Sm0.5Sr0.5CoO3 cathode below 600°C. © 2002 The Electrochemical Society. All rights reserved.