Abstract
Porous carbon nanofibers are fabricated by one-step carbonization and activation of electrospun cellulose acetate (CA) nanofibres. Electrospun CA nanofibers were obtained by the electrospinning of a CA/DMAC/acetone solution, followed by deacetylation in NaOH/ethanol solution. One-step carbonization and activation was achieved by dipping the as-spun fibers in ZnCl(2) solution, followed by one-step high temperature treatment. The effects of the concentration of the dipping solution on the microstructure of the CA-based carbon nanofibers (CACNFs), including the morphology, crystal structure, porous structure, specific surface area and surface chemical properties, have been investigated. The coating of ZnCl(2) effectively improves the thermal stability of electrospun CA nanofibers and obviously enhances the oxygen-containing surface groups of the CACNFs. The CACNFs have a norrow pore size distribution (0.6-1.2 nm) and a high specific surface area (∼1188 m(2) g(-1)). Electrochemical performances of the CACNFs were evaluated as supercapacitor electrodes in 6 M KOH solution. The CACNFs demonstrate high specific capacitance (202 F g(-1) at 0.1 A g(-1)) and excellent rate capability (61% of the retention from 0.1 to 20 A g(-1)). After 5000 cycles of the electrode, the capacitance is maintained at 92%, and the coulombic efficiency is close to 100%, showing high electrochemical stability and reversibility. The renewable features and excellent performance make CACNFs quite a promising alternative to efficient supercapacitor electrodes for energy storage applications.