Improved performance of a symmetrical solid oxide fuel cell by swapping the roles of doped ceria and La_0.6Sr_1.4MnO_4+δin the electrode

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, La_0.6Sr_1.4MnO_4+δ(LSMO₄), was reported to be a potential electrode for SSOFCs, and the modification of LSMO₄surface 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 LSMO₄in electrodes of SSOFCs is exploited, i.e., SDC is applied as the scaffold and LSMO₄as the surface modifier. Different from pristine LSMO₄, the impregnated LSMO₄demonstrates 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 cm²at 700 °C. Under optimized conditions, maximum power densities of 714 and 108 mW cm⁻²at 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 LSMO₄phases 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.