▎ 摘　　要

Traditional electrode materials still face vital challenges of few active sites, low porosity, complex synthesis process, and low specific capacitance. Herein, N-doped and 3D hierarchical porous graphene nanofoam (N-GNF) is created on car-bon fibers (CFs) by employing a facile, fast, and environmentally friendly strategy of N-2 plasma activation. After an appropriated N-2 plasma activation, the graphene nanosheets (GNSs) synthesized by Ar/CH4 plasma deposition transform into N-GNF successfully. N doping donates rich active sites and increases the hydro-philia, while hierarchical nanoarchitecture exposes an enlarged effective contact area at the interface between electrode and electrolyte and affords sufficient space for accommodating more electrolytes. The as-assembled flexible N-GNF@CFs//Zn NSs@CFs Zn ion capacitor delivered a high energy density of 105.2 Wh kg(-1) at 378.6 W kg(-1) and initial capacity retention of 87.9% at the current of 2 A g(-1) after a long cycle of 10,000.