Improving La0.6Sr0.4Co0.2Fe0.8O3-δ cathode performance by infiltration of a Sm0.5Sr0.5CoO3-δ coating

LaxSr1-xCoyFe1-yO3-delta (LSCF) represents one of the state-of-the-art cathode materials for solid oxide fuel cells (SOFCs) due primarily to its high ionic and electronic conductivity. In this study, a one-step infiltration process has been developed to deposit, on the surface of a porous LSCF cathode, a thin film (50-100 nm) of Sm0.5Sr0.5CoO3-delta (SSC), which is catalytically more active for oxygen reduction. Electrochemical impedance spectroscopy reveals that the SSC coating has dramatically reduced the polarization resistance of the cathode, achieving area-specific resistances of 0.036 Omega cm(2) and 0.688 Omega cm(2) at 750 degrees C and 550 degrees C, respectively. It has also maintained the stability of LSCF cathodes. In particular, the peak power densities are increased by similar to 22% upon the infiltration of SSC onto the porous LSCF cathodes of our best performing cells. These results demonstrate that a conductive backbone (e.g., LSCF) coated with a catalytic film (e.g., SSC) is an attractive approach to achieving an active and stable SOFC cathode for low-temperature solid oxide fuel cells. (C) 2009 Elsevier B.V. All rights reserved.