The thermal expansion match of the Gd1-xSrCoO3-delta system to the Ce0.8Gd0.2O1.95 IT-SOFC electrolyte material was examined for x=0 to 0.5. Thermal expansion was measured using dilatometry and a large mismatch in thermal expansion was found. Electrical conductivity was found to exceed 300 S cm(-1) in all compositions prepared. The Sr content in the Gd1-xSxCoO3-delta perovskite was maintained at x = 0.2 for subsequent thermal matching studies. Ce0.8Gd0.2O1.95 additions to the cobaltite material resulted in stable composite cathode materials that showed little interaction among their constituent phases according to X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. High electrical conductivity was maintained for compositions with excellent thermal expansion matching to the IT-SOFC electrolyte material Ce0.8Gd0.2O1.95. (C) 2004 Elsevier B.V. All rights reserved.