Molten salt synthesis of nitrogen-doped hierarchical porous carbon from plantain peels for high-performance supercapacitor

Abstract

© 2022 Elsevier B.V. All rights reserved. This work employs a non-corrosive and non-toxic molten salt combination of NaCl and KCl as an activationagent in an air environment to synthesize nitrogen-doped hierarchical porous carbon from plantain peels at800 degrees C for supercapacitor application. Due to the synergistic effect of nitrogen doping, the synthesized nitro-gen-doped activated unripe porous carbon (AUPN) has a hierarchical (micro-meso-macropores) porous struc-ture and a high surface area of 959 m2/g, providing sufficient active sites for charge storage, rapid electrolyteand ionic mobility. X-ray diffraction and Raman spectroscopy analysis revealed the formation of a carbon pro-duct with a limited degree of graphitization and the crystallite size (La), which is valuable for evaluating thedefects caused by nitrogen doping. In a three-electrode cell with a 6 M KOH electrolyte, AUPN recorded a speci-fic capacitance of 550 F/g at 1 A/g. After 1000 cycles, capacitance retention was 99% at 4 A/g. Compared toother reported porous carbon materials, the overall electrochemical performance of AUPN is superior. This isdue to the abundant nitrogen-doping, which introduces pseudocapacitance and increases the surface wettabil-ity of the porous carbon, resulting in a decrease in ionic-transport resistance.Thesefindings indicate that this green and scalable technique is a potential synthesis method for producingporous carbon materials for energy storage applications.