Ag-BaCe0.8Sm0.2O2.9 (BCS) composite cathodes are fabricated by an ion impregnation technique in this work, and the effect of fabrication details on their electro-performance is studied. The firing temperature of impregnated Ag has little effect on Ag loading but has a great impact on the polarization resistances. When fired at 400 degrees C, the minimum polarization resistance for symmetric cells reaches 0.11 Omega cm(2) measured at 600 degrees C with an Ag loading of 0.40 mg cm(-2). When fired at 600 degrees C, the minimum polarization resistance is 29.73 Omega cm(2) at 600 degrees C with 0.24 mg cm(-2) Ag-impregnated cathodes due to severe aggregation. The performance of Ag-impregnated cathodes is also compared with that of a Sm0.5Sr0.5CoO3-delta (SSC) impregnated cathode. With the same volume ratio of 57%, the polarization resistance of an Ag-impregnated cathode is only about half of that for a SSC-impregnated cathode. Resistance simulation suggests that the reduction of low frequency resistances is the main reason for the decrease in polarization resistances in Ag-impregnated cathodes, which is consistent with its high oxygen diffusion coefficient. With a 57 vol.% Ag-impregnated cathode fired at 400 degrees C, the maximum power density of single cells is 283 mW cm(-2) at 600 degrees C, about 16% larger than that for a 57 vol.% SSC-impregnated cathode. (C) 2010 Elsevier B.V. All rights reserved.