▎ 摘　　要

Graphene and biomass-derived porous carbon materials are the basic materials for designing of many electrochemical energy storage devices. In this regard, we presented an environment-friendly, simple and scalable method for combining the porous carbon, derived from Typha domingensis, as an almost freely available biomass source, and graphene to produce a hierarchical carbon composite with high porosity and conductivity. The physical characteristics of composite were studied by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, thermogravimetric analysis (TGA), Raman spectroscopy, field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM). The electrochemical behaviors of the composite were investigated with two and three electrode systems. The composite used as a positive electrode, in two-electrode assembly, against a Vulcan XC-72R as the negative electrode in 6 M KOH as electrolyte. The specific capacitance of electrode was 277.5 F g(-1) and it retained more than 94% of the initial specific capacitance after 5000 cycles of successive charge/discharge. The two-electrode capacitor had a specific capacitance of 45.8 F g(-1) while it retained 93% of the initial specific capacitance after 5000 cycles of successive charge/discharge. Two cells in series lighted up LED lamps brightly. (C) 2019 Published by Elsevier B.V.