Supercapacitor performance of nitrogen doped graphene synthesized via DMF assisted single-step solvothermal method

Abstract

We report a single step dymethyleformamide (DMF) assisted solvothermally synthesized nitrogen-doped reduced graphene oxide (N-RGO) as a novel electrode material. DMF effectively acts as a nitrogen dopant cum reducing agent for graphene which remarkably enhances its electrochemical properties. X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to characterize the structure and properties of the N-RGO. XRD study confirms effective reduction of GO in the N-RGO. SEM image shows the formation of fluffy and highly porous N-RGO. EDX, XPS and FTIR spectroscopic studies confirm the doping of nitrogen atom into the resultant material (N-RGO). The highest specific capacitance of N-RGO is found to be 516 Fg−1 at a scan rate of 2 mVs−1 along with a good cyclic stability and stable coulombic efficiency. Such a remarkable capacitive performance is attributed to its porous structure and effective nitrogen doping which facilitates the migration of electrolyte ions and provides abundant active sites for such electrochemical behaviour. The electrochemical impedance spectroscopy study showed a typical capacitive behavior of the N-RGO and a faster frequency response with a relaxation time constant of 0.4 s. Thus, the synthesized N-RGO using this simple, cost-effective, environment friendly method could be a potential candidate for high performance energy-storage applications.