La0.65Ca0.35FeO3-δ as a novel Sr- and Co-free cathode material for solid oxide fuel cells

Abstract This study is conducted to evaluate the electrochemical performance of anode-supported solid oxide fuel cells (SOFCs) fabricated with La0.65Ca0.35FeO3-δ (LCaF)-based cathodes. LCaF has a high oxygen permeation flux JO2 compared with typical mixed ionic-electronic conductors composed of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCoF) oxygen permeation membranes. LCaF powder with a high specific surface area (SBET = 9.62 m2 g−1) and high crystallinity is prepared by a citrate-based liquid mixing technique. The anode-supported cell with an LCaF cathode has a high power density of 3.4 W cm−2 at 800 °C under a terminal voltage of 0.7 V. The performance of the cells is further enhanced by preparing a composite cathode of LCaF-Gd-doped CeO2 (GDC). The maximum power density of the cell fabricated with the LCaF-GDC composite cathode reaches 4.4 W cm−2 at 800 °C. Compared with a cell with a cathode prepared from commercial La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCoF), this cell exhibites superior electrochemical performance at all temperatures within the range of 500–800 °C. The high electronic and ionic conductivity of LCaF is presumed to have contributed to the superior electrochemical performance of the anode-supported cells with LCaF-based cathodes. LCaF is found to be a promising candidate as a cathode material for SOFCs.