M. Asamoto, S. Miyake, Y. Yonei, H. Yamaura, H. Yahiro
Proton conductor is the potential candidate as an electrolyte for an intermediate temperature-solid oxide fuel cell (IT-SOFC). However, a major issue with the reduced operating temperature is the decrease in the catalytic activity of the cathode. In the present study, the cathode performances of the perovskite-type oxide were investigated in hydrogen-oxygen SOFC systems using proton conductor. Among the perovskite-type oxides, La-Sr-Fe-O, La-Sr-Mn-O, and La-Sr-Co-O, La-Sr-Fe-O exhibited the lowest cathodic overpotential at the temperature as low as 773 K for SOFC with Sr-Ce-Yb-O proton conducting electrolyte. It was found that the cathodic overpotential of LSFO was much lower than that of Pt. The cathode overpotential increased with the increase in the heat-treatment temperature prior to fuel cell measurement. The electrophoretic deposition (EPD) technique was applied to fabricate cathode materials on electrolyte surface. The overpotential of La-Sr-Fe-O cathode fabricated by the EPD technique was lower than that by the conventional technique. In addition, the sufficient contact between electrode and electrolyte was obtained for the device fabricated by EPD technique. Thus, EPD is promising technique for fabricating the electrode in IT-SOFC with proton conductor.