Improved performance of a symmetrical solid oxide fuel cell by swapping the roles of doped ceria and La0.6Sr1.4MnO4+δ in the electrode

Abstract

Symmetrical solid oxide fuel cells (SSOFCs) show many advantageous features as compared with conventional cells with nickel cermet anode and oxide cathode. A K2NiF4-type layer-structured oxide, La0.6Sr1.4MnO4+δ (LSMO4), was reported to be a potential electrode for SSOFCs, and the modification of LSMO4 surface with samaria-doped ceria (SDC) and NiO was found to be the key in improving performance. In this study, the swapping of roles for SDC and LSMO4 in electrodes of SSOFCs is exploited, i.e., SDC is applied as the scaffold and LSMO4 as the surface modifier. Different from pristine LSMO4, the impregnated LSMO4 demonstrates amorphous phase. Compared to NiO-SDC impregnated LSMO4, NiO-LSMO4/SDC electrodes show a superior cathodic performance with an area specific resistance of 0.1 Ω cm2 at 700 °C. Under optimized conditions, maximum power densities of 714 and 108 mW cm−2 at 800 °C are achieved for an electrolyte-supported symmetrical single cell with a NiO-LSMO4/SDC electrode operating with hydrogen and methane, respectively. The difference in performance of the electrodes built by swapping the role and function of the SDC and LSMO4 phases is discussed, and a possible mechanism responsible for such different behaviours in cell power outputs via the impregnation of LSMO4 (NiO)+SDC electrodes is proposed.