Durability of (Pr0.7Sr0.3)MnO3±δ/8YSZ composite cathodes for solid oxide fuel cells

Half cell SOFCs with (Pr0.7Sr0.3)MnO3 +/-delta/8YSZ composite cathodes on 8YSZ electrolytes were aged up to 1000 h at 1000 degrees C in air with/without 0.318 A cm(-2) cathodic polarization. During the aging, the performance of the half cell SOFCs was measured using electrochemical impedance spectroscopy (EIS). After aging, the surface of the composite cathode and the interface between the composite cathode and the electrolyte was investigated with scanning electron microscopy (SEM). Chemical element analysis was performed with energy dispersive X-ray spectroscopy (EDS). The performance of the half cell SOFCs degraded after aging with/without polarization compared to the initial state. The SOFCs had a larger polarization resistance after 1000 h of aging. The cathodic current was shown to have an impact on the performance by slowing down the rate of decrease of polarization resistance of the SOFCs. After aging, the microstructural properties-mean pore size increased and cumulative pore volume decreased, and growth of grains was found on the (Pr0.7Sr0.3)MnO3 +/-delta phases. (c) 2005 Elsevier B.V. All rights reserved.