Polyacrylonitrile/polyvinyl alcohol‐based porous carbon nanofiber electrodes for supercapacitor applications

Summary Porous carbon nanofibers (PCNFs) were produced from polyacrylonitrile (PAN)/polyvinyl alcohol (PVA) hybrid nanofibers with different mixing ratios and used as the free‐standing, flexible, high performance electrodes for the supercapacitors. The effect of PAN/PVA ratio, PVA removing and stabilization/carbonization process on the chemical structure, and the morphology of PAN/PVA hybrid nanofibers and PCNF were investigated by Fourier transform infrared (FT‐IR), field emission scanning electron microscopy (FE‐SEM), and thermogravimetric analyzer (TGA). It was proved by FT‐IR and FE‐SEM analyses that PAN/PVA hybrid nanofibers are successfully produced and carbonized. In addition, the electrochemical performance of PCNF electrodes was analyzed by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) methods. Results showed that PCNFs exhibit higher specific capacitance and better electrochemical performance than neat carbon nanofibers (N‐CNF). The specific capacitance of the EK5 PCNF (67/33 PAN/PVA wt ratio) was 157 F/g at 5 mV/s scan rate in 1 M H2SO4, while the specific capacitance of N‐CNF was 96 F/g at the same conditions. Moreover, the PCNF showed excellent cyclic stability without losing performance through 2500 charge/discharge cycles at a current density of 2 A/g. As a result, free‐standing, flexible, and high‐performance PCNFs are excellent candidates as supercapacitor electrodes for flexible energy‐storage devices. PAN/PVA hybrid nanofibers with different mixing ratios were produced. PAN/PVA hybrid nanofibers were used as precursors for porous carbon nanofibers. Porous carbon nanofiber mat showed 64% higher specific capacitance compare to neat carbon nanofiber mat. The porous carbon nanofiber electrode maintained its performance over 2500 cycles.