Development of LSCF-GDC composite cathodes for low-temperature solid oxide fuel cells with thin film GDC electrolyte

La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) powder was prepared by glycine-nitrate combustion method. The electrochemical properties of porous LSCF cathodes and LSCF-Gd0.1Ce0.9O1.95 (GDC) composite cathodes were evaluated at intermediate/low temperatures of 500-700 degrees C. The polarization resistance of pure LSCF cathode sintered at 975 degrees C for 2h was 1.20 Omega cm(2) at 600 degrees C. The good performance of pure LSCF cathode is attributed to its unique microstructure-small grain size, high porosity and large surface area. The addition of GDC to LSCF cathode further reduced the polarization resistance. The lowest polarization resistance of 0.17 Omega cm(2) was achieved at 600 degrees C for LSCF-GDC (40:60wt%) composite cathode. An anode-supported solid oxide fuel cell (SOFC) was prepared using LSCF-GDC (40:60wt%) composite as cathode, CDC film (49-mu m-thick) as electrolyte, and Ni-GDC (6S:35wt%) as anode. The total electrode polarization resistance was 0.27 Omega cm(2) at 600 degrees C, which implies that LSCF-GDC (40:60wt%) composite cathode used in the anode-supported SOFC had a polarization resistance lower than 0.27 Omega cm(2) at 600 degrees C. The cell generated good performance with the maximum power density of 562, 422, 257 and 139 mW/cm(2) at 650, 600, 550 and 500 degrees C, respectively. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.