Electrochemical characterization of LaBaCuCoO5+δ-Sm0.2Ce0.8O1.9 composite cathode for intermediate-temperature solid oxide fuel cells

In order to improve the electrochemical performance of the LaBaCuCoO5+delta (LBCC) electrode, LaBaCuCoO5+delta-Ce0.8Sm0.2O1.9 (LBCC-SDC) are prepared and characterized for potential application as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on an SDC electrolyte. Electrical conductivity, thermal expansion and electrochemical properties are investigated by four probing DC technique, dilatometry, AC impedance and polarization techniques, respectively. It is found that the thermal expansion coefficient (TEC) and electrical conductivity decrease with the increase of SDC content in LBCC-SDC composites. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures show that the addition of SDC to LBCC improves the electrochemical performance of a LBCC cathode, and that a LBCC-SDC20 cathode exhibits superior electrochemical performance in the LBCC-SDCx composite cathodes. Moreover, even when the content of SDC is up to 40 wt%, the area specific resistance of the LBCC-SDC40 composite cathode on SDC electrolyte is lower than the corresponding interfacial resistance for pure LBCC at 650-800 degrees C. The power density of the Ni-SDC/SDC/LBCC-SDC20 cell is 615 mW cm(-2) at 800 degrees C. These results indicate that LBCC-SDCx is a potential cathode material for application in IT-SOFCs. (C) 2011 Elsevier Ltd. All rights reserved.