Hierarchical porous carbon nanofibers with enhanced capacitive behavior as a flexible self-supporting anode for boosting potassium storage

Abstract

Carbonaceous materials with various morphologies and structures have been widely investigated as anode for potassium-ion batteries (PIBs), due to their low cost, nontoxicity, and high conductivity. However, there is still sluggish bulk diffusion in most carbon electrodes, which cannot well meet ever-increasing requirements for high power density. Herein, hierarchical porous one-dimensional carbon nanofibers (HPCNF-5) are successfully fabricated, in which one-dimensional (1D) conductivity nanostructure can facilitate electrons transfer. While the in-situ N-doping and suitable micro/mesopores configurations are beneficial for promoting surface-induced capacitive behaviors. Also, the resulting HPCNF-5 has excellent mechanical flexibility, indicating it can be directly used as a self-supporting electrode, thus endowing decreased overall battery weight and promoting reaction reversibility. These prominent structure advantages give HPCNF-5 electrode a fast ions/electrons diffusion capability, thus realizing superior rate property at a high current density of 2 A g−1 (204.6 mAh g−1) and excellent cyclability (with a capacity retention of 88% after 2000 cycles). Therefore, the findings demonstrate the comprehensive merits by combining 1D conductivity nanostructure, N-doping, hierarchical porous, and flexible self-supporting in one material, contributing to offering reference for constructing other advanced carbon materials.