Evaluation of (Bi0.4Sr0.6)xCo0.3Fe0.7O3-δ (x=0.7, 0.8, 0.9, 1.0, 1.1) perovskite-type oxide as potential cathode for intermediate-temperature solid oxide fuel cells

Perovskite-type (Bi0.4Sr0.6)(x)Co0.3Fe0.7O3-delta (BiSCF) oxides with various A-site proportions (x = 0.7, 0.8, 0.9, 1.0 and 1.1, denoted as BiSCF407, BiSCF408, BiSCF409, BiSCF410 and BiSCF411, respectively) have been developed and investigated as cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The crystal structure of the BiSCF sample is refined based on the Pm-3m space group with perfectly cubic structure (a = a(0)). The cells with thick La0.8Sr0.2Ga0.8Mg0.2O3-sigma (LSGM) electrolyte (0.5 mm thickness) and symmetrical BiSCF electrodes are fabricated for electrocatalaytic activity test and it is found that the cell with BiSCF408 shows the lowest polarization resistance of 0.10 Omega cm(2) at 700 degrees C. The LSGM electrolyte-supported (similar to 300 mu m thickness) cell with BiSCF408 cathode exhibits power densities of 0.34 and 0.46 W cm(-2) at 650 and 700 degrees C, respectively, with humidified H-2 (similar to 3% H2O) as the fuel and ambient air as the oxidant. Over 100 h stability test at 600 degrees C indicates that a little performance decrease occurs but no interfacial damage happens even after the long-term operation, suggesting that BiSCF408 is a potential material for IT-SOFCs. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.