Asymmetric Supercapacitor Based on Porous N‑doped Carbon Derived from Pomelo Peel and NiO Arrays

A three dimensional (3D) porous framework-like N-doped carbon (PFNC) with a high specific surface area was successfully fabricated through ammonia doping and graphitization based on pomelo peel. The obtained PFNC exhibits an enhanced specific capacitance (260 F g–1 at 1 A g–1) and superior cycling performance (capacitance retention of 84.2% after 10000 cycles at 10 A g–1) on account of numerous voids and pores which supply sufficient pathways for ion diffusion during cycling. Furthermore, a fabricated asymmetric PFNC//PFN device based on PFNC and porous flake-like NiO (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 kg–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 two light-emitting diodes for 25 min, which demonstrates great application potential.