Composite cathode based on yttria stabilized bismuth oxide for low-temperature solid oxide fuel cells

Composites consisting of silver and yttria stabilized bismuth oxide (YSB) have been investigated as cathodes for low-temperature honeycomb solid oxide fuel cells with stabilized zirconia as electrolytes. At 600 degreesC, the interfacial polarization resistances of a porous YSB-Ag cathode is about 0.3 Omega cm(2), more than one order of magnitude smaller than those of other reported cathodes on stabilized zirconia. For example, the interfacial resistances of a traditional YSZ-lanthanum maganites composite cathode is about 11.4 Omega cm(2) at 600 degreesC. Impedance analysis indicated that the performance of an YSB-Ag composite cathode fired at 850 degreesC for 2 h is severely limited by gas transport due to insufficient porosity. The high performance of the YSB-Ag cathodes is very encouraging for developing honeycomb fuel cells to be operated at temperatures below 600 degreesC. (C) 2003 American Institute of Physics.