Vapor-phase polymerized poly(3,4-ethylenedioxythiophene) (PEDOT)/TiO2 composite fibers were fabricated and applied as the supercapacitor electrode materials. TiO2 fibers were prepared as substrates for the vapor-phase polymerization process, by electrospinning and calcination in air. The symmetric supercapacitor cells assembled with the resulting composites were studied by a series of electrical measurements including cyclic voltammetry, charge-discharge characterization and electrochemical impedance spectroscopy. To further understand the capacitive behavior, the band gap energy of the composite fibers and the specific surface area of TiO2 fibers calcined at varied temperatures were measured. The highest specific capacitance of PEDOT on TiO2 fibers to date, 87.9 Fg(-1), was achieved with the composite fibers prepared by vapor-phase polymerization at 50 degrees C on the TiO2 fibers calcined at 550 degrees C. The pseudocapacitance and the reversibility of PEDOT were improved in comparison to other PEDOT/TiO2 binary composites. (C) 2016 Elsevier Ltd. All rights reserved.