Fabrication and performance of GDC-impregnated (La,Sr)MnO3 cathodes for intermediate temperature solid oxide fuel cells

High-performance (La,Sr)MnO3 (LSM) cathodes for intermediate temperature solid oxide fuel cells were fabricated by the ion impregnation of oxygen ion conducting Gd-doped CeO2 (GDC) oxide. The microstructure of the GDC-impregnated LSM electrode was characterized by the uniform dispersion of very fine GDC particles in the LSM porous framework. The particle size of the impregnated GDC phase was in the range of 100-200 nm. Uniform distribution of the nanosized ionic conducting GDC phase significantly enhanced the electrode activities for the O-2 reduction reaction. In the case of the 5.8 mg cm(-2) GDC-impregnated LSM electrode, electrode polarization resistance was 0.21 Omega cm(2) at 700 degrees C, 56 times lower than that of the pure LSM at the same temperature. GDC-impregnated LSM electrode showed lower activation energy and low reaction order with respect to the partial pressure of oxygen, as compared to that on the pure LSM electrodes. The results indicate that GDC impregnation has significant electrocatalytic effect on the O-2 reduction reactions on the LSM electrodes. (c) 2005 The Electrochemical Society. All rights reserved.