N, P Co-Doped Hierarchically Porous Carbon Fiber for High Performance Zinc-Ion Hybrid Capacitors

Abstract

Multi-heteroatoms co-doped hierarchically porous carbon-based electrode is an effective strategy to solve the low energy density and poor cycle stability of Zn-ion hybrid capacitors (ZHCs). Herein, N and P co-doped porous carbon nanofiber (N-P-PCF) was prepared, which displays fibrous network hierarchically porous structure to fast electron/ Zn2+ transport and enhance Zn2+ adsorption sites. Meanwhile, rich N (9.47 at.%) and P (1.29 at.%) co-doping introduce more defects and then promote Zn2+ storage capability. The N-P-PCF based ZHCs can yield a large specific capacitance (205 mAh g-1 at 1 A g-1), high energy density (173 Wh kg-1 at 823 W kg-1) and excenllent cycle stability for 10000 cycles (98.6% capacity retention), which provides a reliable multi-heteroatoms co-doped porous carbon fiber for high-performance ZHCs.

Keywords: Carbon materials, Porous materials, N and P co-doping, Zinc-ion hybrid capacitors