Synthesis and assessment of La0.8Sr0.2ScyMn1−yO3−δ as cathodes for solid-oxide fuel cells on scandium-stabilized zirconia electrolyte

Perovskite-type La0.8Sr0.2ScyMn1−yO3−δ oxides (LSSMy, y = 0.0–0.2) were synthesized and investigated as cathodes for solid-oxide fuel cells (SOFCs) containing a stabilized zirconia electrolyte. The introduction of Sc3+ into the B-site of La0.8Sr0.2MnO3−δ (LSM) led to a decrease in the oxides’ thermal expansion coefficients and electrical conductivities. Among the various LSSMy oxides tested, LSSM0.05 possessed the smallest area-specific cathodic polarization resistance, as a result of the suppressive effect of Sc3+ on surface SrO segregation and the optimization of the concentration of surface oxygen vacancies. At 850 °C, it was only ~0.094 Ω cm2 after a current passage of 400 mA cm−2 for 30 min, significantly lower than that of LSM (~0.25 Ω cm2). An anode-supported cell with a LSSM0.05 cathode demonstrated a peak power density of 1300 mW cm−2 at 850 °C. The corresponding value for the cell with LSM cathode was 450 mW cm−2 under the same conditions. The LSSM0.05 oxide may potentially be a good cathode material for IT-SOFCs containing doped zirconia electrolytes.