Fabrication and characterization of anode-supported tubular SOFCs with zirconia-based electrolyte for reduced temperature operation

An anode-supported tubular solid oxide fuel cell (SOFC) with a thin electrolyte film for reduced temperature operation was fabricated by a wet cofire process. Instead of the traditional extrusion method, the anode substrate was formed by a tape-cast method. This allows design the substrate with some advantageous configurations that can improve the performance of SOFCs. Sc2O3 and Y2O3-stabilized zirconia electrolyte films were fabricated on the substrate by a modified slurry dip-coating method and then cofired. In order to use (La0.6Sr0.4) CoO3 cathode, a thin (CeO2)(0.9)(GdO1.5)(0.1) interlayer was also fabricated by the slurry dip-coating method. The fabricated tubular cell generated electricity successfully between 600 and 850 degreesC. Power density of ca. 170 and 220 mW/cm(2) was achieved at 600 and 700 degreesC, respectively, however, the ohmic resistance was larger than expected. Because (CeO2)(0.9)(GdO1.5)(0.1) interlayer was used, ohmic resistance could be high due to the formation of a layer of (Zr, Ce)O-2 solid solution at the zirconia/ceria interface. The gaseous diffusion resistance governed the performance between 700 and 850 degreesC. Better performances of the anode-supported tubular SOFCs can be achieved by further optimizations for the zirconia/ceria interface, control of both porosity and thickness of the anode substrate, as well as improvement of the (La0.6Sr0.4) CoO3 cathode. (C) 2004 The Electrochemical Society.