Effects of nitrogen, sulphur, and temperature treatments on the spectral, structural, and electrochemical characteristics of graphene oxide for energy storage applications

Abstract

The structural and surface modifications have been studied on the hydrothermally Nitrogen (N) and Sulphur (S) doped and thermally reduced at 350 °C nitrogen-doped, nitrogen-sulfur-doped graphene oxides. Raman spectra confirmed the reduction of graphene oxides by shifts in position and intensity variations of the D and G bands. EDX and mapping images revealed the carbon-oxygen ratio as well as the doping of nitrogen and sulphur into two-dimensional graphene oxide. The electrochemical properties of undoped and doped graphene oxides were investigated using a three-electrode system using a 1 M KOH electrolyte. It shows how doping, and reduction improve current conduction in graphene oxides. The specific capacitance of N,S-rGO after being synthesized and reduced at 350°C was 930 Fg−1 and 1059 Fg−1, respectively, according to cyclic voltammetry results. The N-rGO specific capacitance was found to be similar, with 850 Fg−1 and 891 Fg−1, respectively, for the as prepared and reduced at 350°C. The charge-discharge analysis, cycle stability, and impedances for the applied frequency ranges of undoped and doped graphene oxides for energy storage applications have all been estimated and discussed.

Keywords

• N,S-doped graphene oxide
• Reduced graphene oxide
• Electrochemical applications
• Thermal reduction
• Surface modifications of graphene oxide