SrNb0.1Co0.9O3-delta (SNC) perovskite oxide has been prepared by high-energy ball milling followed by calcination at 1100 degrees C. According to oxygen temperature-programmed desorption and thermogravimetry analysis results, highly charged Nb5+ successfully stabilizes the perovskite structure to avoid order-disorder phase transition. The electrical conductivity reaches 550 S cm(-1) at 300 degrees C in air and as high as 106 S cm(-1) under P(O-2) = 1 x 10(-5) atm at 900 degrees C. The high electrical conductivity is beneficial in improving the charge-transfer process for the oxygen reduction reaction on the cathode. Based on the defect chemical analysis, the Nb-doping in SrCoO3-delta perovskite facilitates the formation of Co2+, which increases oxygen nonstoichiometry and, subsequently, the mixed valence of [Co2+]/[CO3+] under lower oxygen partial pressure. A relatively low thermal expansion coefficient of 19.1 x 10(-6) K (1) in air was achieved. All above properties show SNC to be a promising cathode material in the practical application of low-temperature solid oxide fuel cells. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved