Structural and electrochemical properties of nanostructured Pd-promoted La(1-x)SRXFEYCO(1-Y)O3-? cathodes for it-sofcs

Nanostructured La1-xSrxCo1-yFeyO3-? perovskites and Ce0.8Gd0.2O2-? fluorite powders were successfully prepared by citrate sol-gel method starting from nitrates of the metal cations. Calcined powders were characterized by XRD and Rietveld refinement, EXAFS and XPS analyses. Electrochemical impedance spectroscopy (EIS) measurements on symmetric cells were performed to evaluate the use of La1-xSrxCo1-yFeyO3-? as a cathode material for intermediate temperature solid oxide fuel cells based on gadolinium doped-ceria electrolytes. Moreover, to improve the performance of LSCF, the effect of Pd doping was investigated. Our results demonstrate that LSCF with 20% mol Fe content (LSCF0.2) has lower ohmic resistance (Rohmic) compared to LSCF with Fe 80% mol (LSCF0.8). In addition, Pd doping decreased both, ohmic (Rohmic) as well as polarization (Rp), resistances for LSCF samples. The best characteristics as cathode at intermediate operating temperatures were found for LSCF0.2-Pd at 690 °C with area specific resistance of 0.07 ? cm2. Copyright © 2013 Delta Energy and Environment.