Robust N-doping porous carbon nanofiber membranes with inter-fiber cross-linked structures for supercapacitors

Enhancing the electrochemical performance while maintaining excellent mechanical properties of carbon nanofiber-based flexible electrodes remains a significant challenge, which blocks their potential application in advanced energy storage and conversion. Herein, taking advantage of the thermal stability difference between polyacrylonitrile and polypyrrolidone, we report a simple strategy to fabricate N-doped porous carbon nanofiber membranes with inter-fiber cross-linked structures via eccentric coaxial electrospinning combined with carbonization processes. During carbonization processes, the obstacles of large contact resistance are removed and sufficient contacts among electrospun nanofibers are formed, endowing the carbon nanofiber membranes with outstanding electrical conductivity (25.4 S cm -1) and flexibility in various forms. Further, NiCo2O4 nanoneedles are in-situ decorated onto the prepared carbon nanofiber membranes to construct hybrid electrodes for improving capacitance. The hybrid electrodes (NiCo2O4@NPCNFs) achieve a competitive specific capacitance (capacity) of 1474.2 F g-1 (245.4 mAh g-1) at the current density of 0.5 A g-1, as well as good rate performance (78.0% capacitance retention at a current density of 10 A g-1). In addition, the assembled asymmetric super -capacitors exhibit a high energy density of 53.0 Wh kg -1. This study paves a promising way toward carbon nanofiber-based electrodes for application in energy storage systems.

Automated summary

In this study, N-doped porous carbon nanofiber membranes with inter-fiber cross-linked structures were successfully fabricated through eccentric coaxial electrospinning and carbonization processes. The prepared carbon nanofiber membranes showed outstanding electrical conductivity and flexibility. Additionally, NiCo2O4 nanoneedles were in-situ decorated onto the carbon nanofiber membranes to construct hybrid electrodes, which exhibited competitive capacitance and good rate performance. The assembled asymmetric supercapacitors also demonstrated a high energy density. These findings pave a promising way for the application of carbon nanofiber-based electrodes in energy storage systems.