Comparative performance of anode-supported SOFCs using a thin Ce0.9Gd0.1O1.95 electrolyte with an incorporated BaCe0.8Y0.2O3-alpha layer in hydrogen and methane

Multilayered Ce0.9Gd0.1O1.95/ BaCe0.8Y0.2O3-alpha/ Ce0.9Gd0.1O1.95 (GDC/BCY/GDC) electrolytes were prepared by tape casting on a Ni - Ce0.8Sm0.2O1.9 anode support. The overall electrolyte thickness ranged from 30 to 35 mu m, including a 3 mu m thick BCY layer. When the multilayered electrolyte cell was tested with hydrogen at the anode and air at the cathode in the temperature range of 500 - 700 degrees C, it yielded open-circuit voltages (OCVs) of 846 - 1024 mV, which were higher than the OCVs of 753 - 933 mV obtained for a single-layered GDC electrolyte cell under the same conditions. The corresponding peak power densities reached 273, 731, and 1025 mW cm(-2) at 500, 600, and 700 degrees C, respectively. The multilayered electrolyte cell could also be applied to direct methane solid oxide fuel cell (SOFC) and single-chamber SOFC operating in a mixture of methane and air. These SOFCs yielded OCVs of 880 - 950 mV and reasonable power densities without coking. (C) 2006 The Electrochemical Society.