The electrochemical performance of ESB [(Bi2O3)(1-x)(Er2O3)(x)]-Ag composite material for IT-SOFC cathode was studied on the SSZ [(ZrO2)(0.89)(Sc2O3)(0.1)(CeO2)(0.01)] electrolyte. The influence of different ESB/Ag ratio and erbium-doped content on the performance of the composite cathode was investigated using AC impedance spectroscopy analysis. The investigation showed that there was a low polarization resistance (0.16 Omega cm(2) to 0.50 Omega cm(2) at temperatures from 750 degrees C to 650 degrees C) when the content of 3ESB [(Bi2O3)(0.7)(Er2O3)(0.3)] and Ag was equal in composite cathode. (C) 2008 Elsevier B.V. All rights reserved.