Asymmetric Supercapacitor\nBased on Porous N‑doped Carbon Derived from Pomelo Peel and\nNiO Arrays

Abstract

A three\ndimensional (3D) porous framework-like N-doped carbon (PFNC) with\na high specific surface area was successfully fabricated through ammonia\ndoping and graphitization based on pomelo peel. The obtained PFNC\nexhibits an enhanced specific capacitance (260 F g^–1 at 1 A g^–1) and superior cycling performance (capacitance\nretention of 84.2% after 10000 cycles at 10 A g^–1) on account of numerous voids and pores which supply sufficient\npathways for ion diffusion during cycling. Furthermore, a fabricated\nasymmetric PFNC//PFN device based on PFNC and porous flake-like NiO\n(PFN) arrays achieves a specific capacitance of 88.8 F g^–1 at 0.4 A g^–1 and an energy density of 27.75 Wh\nkg^–1 at a power density of 300 W kg^–1 and still retains 44 F g^–1 at 10 A g^–1 and 13.75 Wh kg^–1 at power density of 7500 W kg^–1. It is important that the device is able to supply\ntwo light-emitting diodes for 25 min, which demonstrates great application\npotential.