Optimization of BaZr0.1Ce0.7Y0.2O3-δ-based proton-conducting solid oxide fuel cells with a cobalt-free proton-blocking La0.7Sr0.3FeO3-δ-Ce0.8SM0.2O2-δ composite cathode

BaZr0.1Ce0.7Y0.2O3-delta (BZCY)-based proton-conducting solid oxide fuel cells (H-SOFC) with a cobalt-free proton-blocking La0.7Sr0.3FeO3-delta-Ce0.8Sm0.2O2-delta (LSF-SDC) composite cathode were fabricated and evaluated. The effect of firing temperature of the cathode layer on the chemical compatibility, microstructure of the cathode and cathode electrolyte interface, as well as electrochemical performance of single cells was investigated in detail. The results indicated that the cell exhibited the most desirable performance when the cathode was fired at 1000 degrees C; moreover, at the same firing temperature, the power performance had the least temperature dependence. With humidified hydrogen (similar to 2% H2O) as the fuel and ambient air as the oxidant, the polarization resistance of the cell with LSF-SDC cathode fired at 1000 degrees C for 3 h was as low as 0.074 Omega cm(2) at 650 degrees C after optimizing microstructures of the anode and anode-electrolyte interface, and correspondingly the maximum power density achieved as high as 542 mW cm(-2), which was the highest power output ever reported for BZCY-based H-SOFC with a cobalt-free cathode at 650 degrees C. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.