Carbon nanofibers (CNFs) with exposed graphite edges were investigated for use as the electrode material of electrochemical capacitors. Among various modifications of CNFs, the olygoaniline-CNF composite showed the largest capacitance of 149 F/g. The formation of ethynylaniline linkages to the edges of KOH-activated CNFs effectively preserved mesopores. The dynamic properties of this material should be superior to those of the capacitors with micropores. (C) 2004 Elsevier B.V. All rights reserved.