Effect of samaria doped ceria impregnation on the electrochemical performance of strontium doped lanthanum chromium manganite anode for solid oxide fuel cells

Strontium doped lanthanum chromium manganite (LSCM) is a potential ceramic anode material for next-generation hydrocarbonfueled 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.