SOFC Anodes Based on LST–YSZ Composites and on Y0.04Ce0.48ZrM0.48O2
The properties of solid oxide fuel cell (SOFC) anode functional layers prepared by impregnation of 1 wt % Pd and 10 wt % ceria into porous scaffolds of either Y0.04Ce0.48Zr0.48O2 (CZY) or composites of La0.3Sr0.7TiO3 (LST) and yttria-stabilized zirconia (YSZ) were examined to determine whether these scaffold materials would have sufficient electronic and ionic conductivity. Laminated tapes were cofired to produce 50 m YSZ electrolytes and 50 µm scaffolds, supported on LSF–YSZ cathodes. The electronic conductivities of LST–YSZ composites were a function of the porosity and the weight fraction of LST but could be sufficient for use in thin functional layers. However, anodes made with LST–YSZ composites had higher nonohmic losses than cells made with YSZ scaffolds. With CZY scaffolds, some migration of Ce into the YSZ electrolyte was observed after cofiring. While CZY exhibited electronic conductivity, the loss in ionic conductivity compared to YSZ again resulted in higher nonohmic losses. The implications of these results for producing better ceramic anodes are discussed.