LAUSR

Abstract We report simple and cost effective production of water soluble graphene sheets using coal. The synthesized coal derived graphene (CDG) sheets were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), Raman, Fourier transform infrared (FTIR), ultra-violet visible (UV–vis) spectroscopy, and photoluminescence (PL) measurements. The presence of edge oxygen functionalities in CDG sheets causes to induce fluorescent properties. The nature emission peak does not change with varying the excitation wavelength. To determine its energy storage properties, cyclic voltammetry (CV), charge-discharge and electrochemical impedance spectroscopy (EIS) measurements were done in different electrolytes. The value of specific capacitance (SC) of CDG in 1 M Na2SO4 electrolyte turns out to be 277 F/g at scan rate of 5 mV/s. CDG show long cycle stability i.e., the value of SC remains at ~91% after 2000 cycles at the current density of 10 mA/g.