High-performance Y0.9In0.1BaCo3(Zn,Fe)O7 + δswedenborgite-type oxide cathodes for reduced temperature solid oxide fuel cells

Abstract

With the goal of improving the electrochemical performance while maintaining good phase stability, the Fe-substituted swedenborgite-type Y0.9In0.1BaCo3Zn1 − xFexO7 + δ series of oxides have been investigated as cathode materials for solid oxide fuel cells (SOFCs). All the samples with 0 ≤ x ≤ 0.8 were obtained as single-phase oxides with the P31c space group. Both the x = 0 and 0.2 samples were stable after 120 h exposure to 600, 700, and 800 °C, while the x = 0.6 and 0.8 samples showed instability at 700 and 800 °C. The x = 0.4 sample was stable at 600 and 800 °C, but generated a BaCoO3 impurity phase at 700 °C. The reversible oxygen absorption tendency of these materials was found to increase with increasing Fe content. Increasing the Fe content in the range of 0 ≤ x ≤ 0.4 was found to reduce the polarization resistance in the Y0.9In0.1BaCo3Zn1 − xFexO7 + δ + Gd0.2Ce0.8O1.9 composite cathodes, and the x = 0.4 sample was found to have performance superior to that of the well-studied Ba0.5Sr0.5Co0.8Fe0.2O3 − δ (BSCF) cathode in the range of 400–700 °C, making it an attractive cathode candidate for intermediate temperature SOFCs.