Evaluation and performance optimization of double-perovskite LaSrCoTiO5+δ cathode for intermediate-temperature solid-oxide fuel cells

Double-perovskite LaSrCoTiO5+delta (LSCT) is synthesized in air by a modified sol gel method and investigated as a cathode material for intermediate-temperature solid-oxide fuel cells (IT-SOFCs). The LSCT material exhibits good chemical compatibility with LaGaO3-/CeO2-based electrolytes at 1000 degrees C for 10 h. XPS analysis shows that Co in the LSCT material exists in two valence states, i.e., Co3+/Co2+. The electrical conductivity of the LSCT material gradually increases with increasing temperature, an increase that corresponds to semiconductor-like behavior. Compared with LaSrCo2O5+delta material, the substitution of Ti for Co efficiently reduces the average thermal expansion coefficient. The area-specific resistance and maximum power density are 0.056 Omega cm(2) and 776 mW cm(-2) at 800 degrees C respectively. The addition of an appropriate amount of SDC into LSCT to form LSCT-SDC composite cathodes further reduces the TEC and improves cathode performance. Results demonstrate that LSCT and LSCT-SDC composite materials are promising candidates for IT-SOFC cathodes. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.