Superior one-pot synthesis of a doped graphene oxide electrode for a high power density supercapacitor

Abstract

In this work, we report the synthesis of sulfur-doped reduced graphene oxide (S-rGO) using sodium borohydride (NaBH₄) and sodium sulfide (Na₂S) by a facile one-pot approach via refluxing in deionised water. The undoped rGO chemical structure is partially reduced by NaBH₄, whereas the addition of a small amount of Na₂S with NaBH₄ resulted in a better reduction of rGO. XPS analysis confirmed the successful doping of sulfur and Raman spectroscopy verified the increased defect density. The S-rGO electrode exhibits good power density (3202 W kg⁻¹) with increased specific capacitance (392 F g⁻¹) and cyclic stability (91%, 2000 cycles) in 1 M Na₂SO₄ aqueous electrolyte. The obtained results suggest that the simple tuning of the graphene oxide structure using Na₂S with NaBH₄ enhances the above properties. Moreover, this method is facile and allows the easy reproduction of bulk quantities of materials for use in commercial applications.