In this work, activated carbon nanofiber(ACNF) electrodes with high double-layer capaci-tance and good rate capability were prepared from polyacrylonitrile nanofibersby optimiz-ing the carbonization temperature prior to H2O activation. The morphology of the ACNFs was observed by scanning electron microscopy. The elemental composition was determined by analysis of X-ray photoelectron spectroscopy. N2-adsorption-isotherm characteristics at 77 K were confirmedby Brunauer-Emmett-Teller and Dubinin-Radushkevich equations. ACNFs processed at different carbonization temperatures were applied as electrodes for electrical double-layer capacitors. The experimental results showed that the surface mor-phology of the CNFs was not significantlychanged after the carbonization process, although their diameters gradually decreased with increasing carbonization temperature. It was found that the carbon content in the CNFs could easily be tailored by controlling the carbonization temperature. The specificcapacitance of the prepared ACNFs was enhanced by increasing the carbonization temperature.

Activated carbon nanofibers(ACNF) were prepared from polyacrylonitrile (PAN)-based nanofibersusing CO2 activation methods with varying activation process times. The surface and structural characteristics of the ACNF were observed by scanning electron microscopy and X-ray diffraction, respectively. N2 adsorption isotherm characteristics at 77 K were con-firmedby Brunauer-Emmett-Teller and Dubinin-Radushkevich equations. As experimental results, many holes or cavernous structures were found on the fibersurfaces after the CO2 activation as confirmedby scanning electron microscopy analysis. Specificsurface areas and pore volumes of the prepared ACNFs were enhanced within a range of 10 to 30 min of acti-vation times. Performance of the porous PAN-based nanofibersas an electrode for electrical double layer capacitors was evaluated in terms of the activation conditions.