PrBaCo2O5+delta-Ce0.8Sm0.2O1.9 (PBCO-SDC) composite material are prepared and characterized as cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction result proves that there are no obvious reaction between the PBCO and SDC after calcination at 1100 degrees C for 3 h. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures shows that the addition of SDC to PBCO improved remarkably the electrochemical performance of a PBCO cathode, and that a PBCO-30SDC cathode exhibits the best electrochemical performance in the PBCO-xSDC system. The total interfacial resistances R-p is the smallest when the content of SDC is 30 wt%, where the value is 0.035 Omega cm(2) at 750 degrees C, 0.072 Omega cm(2) at 700 degrees C, and 0.148 Omega cm(2) at 650 degrees C, much lower than the corresponding interfacial resistance for pure PBCO. The maximum power density of an anode-supported single cell with PBCO-30SDC cathode, Ni-SDC anode, and dense thin SDC/LSGM (La0.9Sr0.1Ga0.8Mg0.2O3-delta)/SDC tri-layer electrolyte are 364, 521 and 741 mW cm(-2) at 700, 750 and 800 degrees C, respectively. (C) 2009 Elsevier B.V. All rights reserved.