Application of electrochemically prepared carbon nanofibers in supercapacitors

Supercapacitive behavior of electrochemically synthesized carbon nanofibers by the controlled reduction of chloroform at room temperature is demonstrated. The important advantage of the electrochemical route is in situ functionalization of carbon fibers (Us), which can be controlled by the nature of the precursor. The FTIR spectrum of as-prepared Us reveals substantial amounts of functionalized species, namely, -OH, =O, -COOH, etc., while scanning electron micrographs show Us packed in bundles of 25 mum. The presence of amorphous carbon as well as traces of a graphitic phase is confirmed by means of thermogravimetric analysis (TGA) and X-ray diffraction (XRD), respectively. The capacitive behavior of the carbon nanofibers is studied in terms of charge-discharge curves and cyclic voltammograms. A specific capacitance of 28 F g(-1) is obtained for a measured surface area of 78 m(2) g(-1). Thermal treatment does not cause a chan-e in surface structure as well as capacitive behavior of the carbonaceous materials although there is an increase in surface area to 592 m(2) g(-1). (C) 2002 Published by Elsevier Science B.V.