Development of High Performance Ceria/Bismuth Oxide Bilayered Electrolyte SOFCs for Lower Temperature Operation

Abstract

This study examines the development of lower temperature solid oxide fuel cells (SOFCs) and the incremental improvement in performance obtained from a wide range of techniques, from pressed anodes to tape-cast anodes, from gadolinia-doped ceria (GDC) single-layer electrolytes to erbium-stabilized bismuth oxide (ESB)/GDC bilayer, and from La0.6Sr0.4Co0.2Fe0.8O3-delta-GDC composite cathodes to optimized Bi2Ru2O7-ESB composites. GDC single-layer electrolyte-based SOFCs were prepared from four different fabrications and exhibit maximum power densities ranging from 0.338 to 1.03 W/cm(2) at 650 degrees C. At each fabrication stage, an ESB layer was applied to form a bilayer electrolyte. ESB was deposited by a range of techniques including colloidal deposition and pulsed laser deposition. The result confirms that depending on a fabrication route, the bilayer electrolyte can reduce the total area specific resistance (ASR) 33-49% and increase the maximum power density 44-93%. By using a combination of the materials and fabrication routes, a maximum power density of 1.95 W/cm(2) and 0.079 cm(2) total cell ASR was achieved at 650 degrees C for a bilayer cell.