SrCo0.7Fe0.2Ta0.1O3-δ perovskite as a cathode material for intermediate-temperature solid oxide fuel cells

Perovskite oxide SrCo0.7Fe0.2Ta0.1O3-delta (SCFT) was synthesized by a solid-state reaction and investigated as a potential cathode material for intermediate-temperature solid oxide fuel cell (IT-SOFC). The single phase SCFT having a cubic perovskite structure was obtained by sintering the sample at 1200 degrees C for 10 h in air. Introduction of Ta improved the phase stability of SCFT. The SCFT exhibited a good chemical compatibility with the La0.9Sr0.1Ga0.8Mg0.2O3-delta (LSGM) electrolyte at 950 degrees C for 10 h. The average thermal expansion coefficient was 23.8 x 10(-6) K-1 between 30 and 1000 degrees C in air. The electrical conductivities of the SCFT sample were 71-119 S cm(-1) in the 600-800 degrees C temperature range in air, and the maximum conductivity reached 247 S cm(-1) at 325 degrees C. The polarization resistance of the SCFT cathode on the LSGM electrolyte was 0.159 Omega cm(2) at 700 degrees C. The maximum power density of a single-cell with the SCFT cathode on a 300 mu m-thick LSGM electrolyte reached 652.9 mW cm(-2) at 800 degrees C. The SCFT cathode had shown a good electrochemical stability over a period of 20 h short-term testing. These findings indicated that the SCFT could be a suitable alternative cathode material for IT-SOFCs. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.