Preparation and characterization of graded SSC–SDC MIEC cathode for low-temperature solid oxide fuel cells

Mixed ionic/electronic conductor (MIEC) cathodes with graded composition and microstructures have been fabricated using improved spin-coating technique. Two components, Sm0.2Ce0.8O1.9 (SDC) and Sm0.5Sr0.5CoO3 (SSC), were utilized to prepare the graded MIEC cathode. Graded microstructures, i.e., a SSC-rich outer layer with large interconnected pores and a SDC-rich inner layer with small interconnected pores, were observed. The corresponding single cell had an increase of 13.3% in maximum power density at operating temperature of 600 °C. The present work suggests that the graded MIEC cathode has great potential in improving performance of solid oxide fuel cells operated at lower temperature.