Phase stability and electrochemical performance of Y0.5Ca0.5-xInxBaCo3.2Ga0.8O7+delta (x=0 and 0.1) as cathodes for intermediate temperature solid oxide fuel cells

摘要

Y0.5Ca0.5-xInxBaCo3.2Ga0.8O7+delta (x = 0.0 or 0.1, and denoted as YCBCG, YCIBCG, respectively) oxides are synthesized and investigated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The In content (x) significantly affects the properties of Y0.5Ca0.5-xInxBaCo3.2Ga0.8O7+delta. The YCIBCG oxide exhibit superior phase stability compared to YCBCG at high temperatures (700-950 degrees C). The substitution of In for Ca improves the long-term phase stability at higher temperatures, but slightly degrades the electrochemical performance. Thermal expansion coefficient (TEC) values of the YCBCG and YCIBCG oxides are 9.8 x 10(-6) K-1 and 9.7 x 10(-6) K-1 in the range of 30-850 degrees C, respectively, which provides good mechanical compatibility with the electrolyte (10.9 x 10(-6) K-1 for LSGM). The interfacial polarization resistances for YCBCG and YCIBCG cathode are as low as 0.140 Omega cm(2) and 0.146 Omega cm(2) at 700 degrees C, respectively. The maximum power densities of the NiO-SDC/SDC/LSGM/YCBCG and NiO-SDC/SDC/LSGM/YCIBCG cells are 434 and 415 mW cm(-2) at 800 degrees C, respectively with a 300 mu m thick electrolyte. The results of this study demonstrate that YCBCG and YCIBCG are very promising cathode materials for intermediate temperature SOFCs. (C) 2016 Elsevier B.V. All rights reserved.