Enhanced performance of La0.8Sr0.2MnO3 cathode for solid oxide fuel cells by co-infiltration of metal and ceramic precursors

Abstract

The electrochemical performance of a La0.8Sr0.2MnO3 (LSM) cathode electrode of solid oxide fuel cells (SOFCs) was promoted by the infiltration of metallic (Ag) and ceramic (La0.8Sr0.2FeO3 (LSF), CeO2) nano-catalysts. Electrochemical and microstructural techniques were used to investigate the effects of the addition of the infiltrated materials. The SEM observations showed that a well-dispersed arrangement of catalyst nano-particles is formed on the micron-sized LSM backbone. Electrochemical impedance spectroscopy (EIS) along with the analysis of distribution of relaxation time (DRT) and polarization measurement were conducted using a three electrode configuration setup. The EIS results revealed that the effect of the Ag nano-catalyst in lowering the polarization resistance is more sensible at lower temperatures, whereas LSF has more impact on the reduction of polarization resistance at higher temperatures. The best performance enhancement was achieved by the co-infiltration of Ag-ceria into the LSM electrode. The co-infiltration of Ag and ceria reduced the polarization resistance of the electrode to 2.5% of that for the pure LSM electrode. Furthermore, the infiltration of Ag solution reduced the electrode overpotential by about 114% at 700 °C.