InBaCo4-xZnxO7 oxides have been synthesized and characterized as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFC). The effect of Zn substitution for Co on the structure, phase stability, thermal expansion, and electrochemical properties of the InBaCo4-xZnxO7 has been investigated. The increase in the Zn content from x = 1 to 1.5 improves the high temperature phase stability at 600 degrees C and 700 degrees C for 100 h, and chemical stability against a Gd(0.2)Ce(0.8)o(1.9) (GDC) electrolyte. Thermal expansion coefficient (TEC) values of the InBaCo(4-x)Zn(x)o(7) (x = 1, 1.5, 2) specimens were determined to be 8.6 x 10(-6) to 9.6 x 10(-6)/degrees C in the range of 80-900 degrees C, which provides good thermal expansion compatibility with the standard SOFC electrolyte materials. The InBaCo4-xZnxO7 +GDC (50:50 wt.%) composite cathodes exhibit improved cathode performances compared to those obtained from the simple InBaCo4-xZnxO7 cathodes due to the extended triple-phase boundary (TPB) and enhanced oxide-ion conductivity through the GDC portion in the composites. (C) 2011 Elsevier Ltd. All rights reserved.