International Journal of Hydrogen Energy, Vol.37, No.3, 2546-2551, 2012
SmBa0.5Sr0.5Cu2O5+delta and SmBa0.5Sr0.5CuFeO5+(delta) layered perovskite oxides as cathodes for IT-SOFCs
Novel Cobalt-free layered perovskite oxides SmBa0.5Sr0.5Cu2O5+delta (SBSCO) and SmBa0.5 Sr0.5CuFeO5+delta (SBSCFO) were investigated as cathode materials for intermediate-temperature solid fuel cells (IT-SOFCs). The thermal expansion coefficients (TEC) of SBSCO and SBSCFO were 14.1 x 10(-6)/degrees C and 14.9 x 10(-6)/degrees C in 50 degrees C-800 degrees C, which were more compatible with electrolyte than cobalt-based cathodes. When A'-site is partially substituted by Sr, the conductivity of SBSCO and SBSCFO had been improved. The max electrical conductivity of SBSCO was 277.7 S cm(-1), about one order of magnitude higher than SmBaCu2O5+delta. Polarization resistance of SBSCO is 0.25 Omega cm(2) at 650 degrees C, which is twice lower than that of SmBaCu2O5+delta (SBCO). This implies SBSCO has higher activity for oxygen reduction than SBCO. Preliminary results indicate that SBSCO are promising as cathodes for IT-SOFCs. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.