SmBaCoCuO5+delta-xCe(0.9)Gd(0.1)O(1.95) (SBCCO-xGDC, x = 10, 30, 50, 60, wt%) composite cathodes have been investigated for their potential utilization in intermediate temperature solid oxide fuel cells (IT-SOFCs). The thermal expansion behavior shows that the thermal expansion coefficient (TEC) values of SBCCO cathode decrease with GDC addition. The TEC of SBCCO-50GDC cathode is 13.1 x 10(-6) K-1 from 30 to 850 degrees C in air. By means of DC polarization and AC impedance spectroscopy, the electrochemical performance of SBCCO-xGDC composite cathodes on GDC electrolyte is examined. Results indicate that the proper addition of GDC could improve the performance of SBCCO cathode. The optimum content of GDC in the composite cathodes is 50 wt% with the polarization resistance (R-p) of 0.040 Omega cm(2) at 800 degrees C. An electrolyte-supported single-cell configuration of SBCCO-50GDC/GDC/Ni-GDC attains a maximum power density of 628 mW cm(-2) at 800 degrees C. Preliminary results indicate that SBCCO-50GDC is especially promising as a cathode for IT-SOFCs. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.