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-delta 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 Sc+ into the B-site of La0.8Sr0.2MnO3-delta (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 degrees C, it was only similar to 0.094 Omega cm(2) after a current passage of 400 mA cm(-2) for 30 min, significantly lower than that of LSM (similar to 0.25 Omega cm(2)). An anode-supported cell with a LSSM0.05 cathode demonstrated a peak power density of 1300 mW cm(-2) at 850 degrees 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. (C) 2008 Elsevier B.V. All rights reserved.