β-Cyclodextrin-assisted fabrication of hierarchically porous carbon sheet with O/N defects for electrical double-layer supercapacitor

The development of an efficient synthesis process for carbon-based supercapacitor electrodes is highly appreciated for its practical application. In this work, using β-cyclodextrin (O and C sources), melamine (C and N sources) and zinc chloride (active agent) as affordable precursors, we proposed a cost-efficient route integrating one-pot hydrothermal treatment and in situ carbonization/activation to obtain a N/O co-doped hierarchically porous carbon sheets and employ them as a potential electrode for supercapacitor. The β-cyclodextrin with abundant hydrophobic cavity assists the formation of porous architecture with a large specific surface area (SSA) of 1427 m2 g−1. The materials are systematically characterized using various technologies including SEM, XRD, Raman, TEM and XPS measurements. Further, the supercapacitor performances are analyzed using cyclic voltammetry at different scan rates, ac impedance and galvanostatic charge/discharge measurement. A specific capacitance of 240 F g−1 (at 0.5 A g−1) and 120 F g−1 (at 0.3 A g−1) could be obtained in three-electrode system and symmetric two-electrode full device measurements, respectively. This work points out a new avenue for the fabrication of carbon-based high-performance supercapacitors.