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

Abstract

3D porous carbon nanosheets have attracted tremendous concern for their large opened layer with an ultrahigh specific surface area and superb electronic transportation capability. However, the high cost of traditional carbon nanosheet materials such as graphene and its derivatives is not sufficiently economical for their application on a large scale; low cost and facile alternatives have been long-pursued. Here, an extra facile one-pot synthesis method was adopted to transform forestry waste into a highly porous carbon nanosheet under a relatively low temperature (e.g., 700 °C) by copper bromide (CuBr2), and the structure of the obtained carbon materials can be adjusted easily by temperature control. As a result, the obtained bark-based carbon (BC) shows a delightful 3D porous nanosheet structure and ultrahigh specific surface area in the range of 1955–2396 m2 g–1; the optimal sample even demonstrates an excellent performance in energy storage. The as-prepared BC-700-based supercapacitor shows a delightful capacitance (e.g., 345 F g–1), and outstanding capacitance retention (e.g., 98.3%) after 10 000 charge–discharge cycles at 5 A g–1 in a 6.0 M KOH aqueous electrolyte system. Moreover, the BC-700-based symmetric supercapacitor demonstrates an attractive energy density as high as 24.3 Wh kg–1 at 224.9 W kg–1 in a 1.0 M Na2SO4 aqueous electrolyte system. This facile strategy provides a promising prospect for the translation of the various kinds of agricultural and forestry residues into high-value-added carbon materials which is full of potential application value.