Polyaniline-V2O5 hybrid materials have been prepared by an oxidative intercalation reaction and the factors that affect their electrochemical discharge-charge performance have been investigated. The first discharge capacity of a sample produced from a nominal molar ratio of aniline: V2O5 = 3 (V2O5-(AN)3.0) is higher than that of a sample prepared from the lower ratio of aniline: V2O5 = 0.5 (V2O5-(AN)0.5). The V2O5-(AN)0.5 sample also shows better reversibility. Samples have been post-treated at different temperatures in air or oxygen. Post-treatment improves the electrochemical performance of V2O5-(AN)0.5 but degrades both the capacity and reversibility of V2O5-(AN)3.0. A V2O5-(AN)0.5 sample post-treated at 70degreesC in air exhibits the best discharge-charge characteristics. (C) 2004 Elsevier B.V. All rights reserved.