Bark-Based 3D Porous Carbon Nanosheet with Ultrahigh\nSurface Area for High Performance Supercapacitor Electrode Material

Abstract

3D\nporous carbon nanosheets have attracted tremendous concern for\ntheir large opened layer with an ultrahigh specific surface area and\nsuperb electronic transportation capability. However, the high cost\nof traditional carbon nanosheet materials such as graphene and its\nderivatives is not sufficiently economical for their application on\na large scale; low cost and facile alternatives have been long-pursued.\nHere, an extra facile one-pot synthesis method was adopted to transform\nforestry waste into a highly porous carbon nanosheet under a relatively\nlow temperature (e.g., 700 °C) by copper bromide (CuBr₂), and the structure of the obtained carbon materials can be adjusted\neasily by temperature control. As a result, the obtained bark-based\ncarbon (BC) shows a delightful 3D porous nanosheet structure and ultrahigh\nspecific surface area in the range of 1955–2396 m² g^–1; the optimal sample even demonstrates an excellent\nperformance in energy storage. The as-prepared BC-700-based supercapacitor\nshows a delightful capacitance (e.g., 345 F g^–1),\nand outstanding capacitance retention (e.g., 98.3%) after 10 000\ncharge–discharge cycles at 5 A g^–1 in a 6.0\nM KOH aqueous electrolyte system. Moreover, the BC-700-based symmetric\nsupercapacitor demonstrates an attractive energy density as high as\n24.3 Wh kg^–1 at 224.9 W kg^–1 in\na 1.0 M Na₂SO₄ aqueous electrolyte system. This\nfacile strategy provides a promising prospect for the translation\nof the various kinds of agricultural and forestry residues into high-value-added\ncarbon materials which is full of potential application value.