Effect of Samaria Doped Ceria Impregnation on the Electrochemical Performance of Strontium Doped Lanthanum Chromium Manganite Anode for Solid Oxide Fuel Cells

Abstract

Strontium doped lanthanum chromium manganite (LSCM) is a potential ceramic anode material for next-generation hydrocarbon-fueled solid oxide fuel cells. Because of its relatively low electrochemical performance, however, its application is still limited. This work investigated the effect of samaria-doped ceria (SDC) impregnation on the electrode performance regarding the surface reaction and oxygen-ion transport in the electrode reaction. The results showed that the electrochemical performance had been promoted by incorporating with nano-SDC particles. Electrical conductivity relaxation (ECR) of dense LSCM exhibited significant improvement in the surface exchange coefficient, from 5.34 × 10−6 cm s−1 at 850°C for bare LSCM to 1.48 × 10−4 cm s−1 for LSCM coated with 0.9 mol L−1 SDC precursor solution. The surface reaction promotion factor was about 28 for the nano SDC particle coating, much higher than the factor of 6.5 for LSCM-SDC composite. It was demonstrated that the promotion in surface reaction rate are mainly contributed by LSCM-SDC-gas three-phase boundaries (3PB). Interfacial polarization resistances of SDC impregnated LSCM symmetrical cells presented over 1 order of magnitude reduction at 850°C with a SDC loading of 35.8 wt%. The electrode performance improvement was attributed to the connective oxygen ion conduction path and increased 3PB formed by the impregnated SDC particles.