High Performance Supercapacitor Electrode Materials from Electrospun Carbon Nanofibers in Situ Activated by High Decomposition Temperature Polymer

Most previous works on in situ activation of electrospun carbon nanofibers have usually used a sacrificing polymer with a low decomposition temperature (e.g., less than 300 °C) as an activation agent, which leads to limited mesoporous structure and surface area in the carbon nanofibers. In this study, we have prepared carbon nanofibers by carbonization of electrospun polyacrylonitrile (PAN) in the presence of a high decomposition temperature polymer, polysulfone (PSF), which is homogeneously blended with PAN. The use of PSF as in situ activation agent largely increased mesopore content, specific surface area, graphitization degree, interfiber connection, and conductivity in the carbon nanofibers. The PAN/PSF ratio showed an effect on these properties, and 20% PSF within the precursor nanofibers (based on the polymer weight) had the best results. When using the PAN/PSF derived carbon nanofibers as an electrode material, the prepared supercapacitor showed a specific capacitance as high as 289 F/g at the scan rate of 10 mV/s and 257 F/g at the current density of 0.25 A/g. The device had excellent cycling stability (100% capacitance retention after 6000 cycles) and large energy capability (∼36 Wh/kg). Carbon nanofibers activated with PSF may serve as a high performance electrode material for supercapacitor applications.