Facile Fabrication of N-doped Carbon Derived from Kiwi Fruit Peel for Advanced Supercapacitor

Abstract

As a potential material, biomass material has become a hot spot for energy storage equipment because of its enhanced properties and environmental-friendly features. Waste kiwi fruit peel is a kind of biomass material with a natural macroporous structure. After carbonization, acid pickling and activation, the kiwi fruit peel carbon (KFPC) with a 3D porous structure composed of macropores, mesopores and micropores on its surface and inner channels, respectively. The morphology and structure of the KFPC are studied by scanning electron microscopy (SEM). The electrochemicial properties were analyzed in a three-electrode system. The cyclic voltammetry (CV) measurement at the scan rate of 5-100 mV s-1 in 2 M KOH aqueous electrolyte. The Galvanostatic charge/discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) are used to calculate the specific capacitance and resistance, respectively. The KFPC exhibits a 2290 m2 g-1 specific surface area. The capacitor has a specific capacitance of 249.8F g− 1 at 1 A g− 1 and a capacity retention rate of 89.22 % after 5000 cycles at 5 A g− 1, indicating that the KFPC is relatively stable. After assembling the materials into a symmetric supercapacitor, it delivered a high energy density of 9.75 Wh kg-1, which reveals the promising application of KFPC in high-performance supercapacitors.