The performance of SmBaCoFeO(5+delta) (SBCF)-xCe(0.9)Gd(0.1)O(1.95) (GDC) (x = 0, 10, 30, 50, 60, wt%) composite cathodes has been investigated for their potential utilization in intermediate-temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction (XRD), thermal expansion coefficient (TEC) and electrochemical property measurements are employed to study the materials. The XRD results prove that there is no serious reaction between SBCF and GDC oxides even at 1000 degrees C. The thermal expansion behavior shows that the TEC value of SBCF cathode decreases greatly with GDC addition. The addition of GDC to SBCF cathode further reduces the polarization resistance. The lowest polarization resistance of 0.036 0 cm(2) is achieved at 800 degrees C for SBCF-50GDC composite cathode. An electrolytesupported fuel cell is prepared using SBCF-50GDC as cathode and NiO-GDC (65:35 by weight) as anode. The cell generates good performance with the maximum power density of 691 mW cm(-2), 503 mW cm(-2) and 337 mW cm-2 at 800 degrees C, 750 degrees C and 700 degrees C, respectively. Preliminary results indicate that SBCF-50GDC is especially promising as a cathode for ITSOFCs. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.