Preparation and electrochemical properties of carbon nanofibers derived from polybenzimidazole/polyimide precursor blends

Carbon nanofibers (CNFs) were fabricated by thermal treatment of electrospun nanofibers obtained from precursor blends of polybenzimidazole (PBI) and Matrimid (R). The microcarbon structures of CNFs obtained from PBI, and the 50:50 and 75:25 blends were studied using XRD and Raman spectra. Nitrogen adsorption/desorption measurements revealed that surface area and porosity of CNFs increased with an increase in Matrimid (R) content. Electrochemical performance of these CNF electrodes was studied for their application in energy storage devices. The CNFs from the PBI/Matrimid (R) (75:25)-precursor blend showed the lowest electrochemical impedance, and highest specific capacitance (111 F/g) and energy and power densities of 24 and 6 kW/kg, respectively. Steam activation and annealing further enhanced the performance resulting in a specific capacitance of 126 F/g, and energy and power densities of 49 and 7 kW/kg, respectively. (C) 2012 Elsevier Ltd. All rights reserved.