Nanoscopic spheres of poly(3,4-ethylenedioxythiophene) from its poly(styrene sulfonate) stabilised dispersion was converted to nanofibers by acid treatment. The nanofibers showed a conductivity of 1800 S/cm. The specific capacitance of nanofiber based supercapcitors increased by 10 times compared to nanospeheres. The specific capacitance and power density were found to be 288 F/g and 9491 W/kg. (C) 2017 Elsevier Ltd. All rights reserved.