Preparation and characterization of lead ruthenate based composite cathodes for SOFC applications

Nanometric pyrochlore lead ruthenate (Pb2Ru2O6.5) powders were prepared using a new chemical route as a possible candidate for cathode materials in solid oxide fuel cells (SOFCs). Pb2Ru2O6.5 was mixed with yttria-stabilized zirconia (YSZ) and erbia-stabilized bismuth oxide (ESB) to fabricate porous composite electrodes. Pure pyrochlore or composite electrodes were deposited as thick films onto YSZ and ESB electrolytes. Powders and films were analyzed using X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM). Electrochemical features of the electrodes were investigated using electrochemical impedance spectroscopy (EIS) measurements at different temperatures in air for symmetric cells. The composite electrodes were compared to single Pb2Ru2O6.5 phase electrodes to evaluate the effect on polarization of the addition of the pure ionic conductor phase in the electrodes.