Efficient electrochemical synthesis of 2H-MoS2/S-Doped graphene oxide composites for Binder-Free High-Performance supercapacitor electrodes

Abstract

The objective of this research is to examine the synthesis and characterization of molybdenum disulfide (MoS₂) and sulphur-doped graphene oxide (S-GO) composites as potential materials for advanced supercapacitors. The study reports the first use of 2H-MoS₂@SG-based materials, synthesized via an electrochemical method at room temperature, as binder-free electrode materials in supercapacitors. The synthesis of 2H-MoS₂ involved cyclic voltammetry (CV), while sulfur-doped graphene oxide (SGO) was synthesized using chronoamperometry (CA). The materials were comprehensively characterized using various techniques, including Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction (XRD), to gain insights into their chemical structure. The surface morphology of the composites was examined using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX). Additionally, the capacitive behavior changes over numerous cycles were evaluated through cyclic voltammetry, electrochemical impedance spectroscopy, and cyclic charge/discharge tests. The highest specific capacitance achieved was 532.8 mF cm⁻² at 10 mA cm⁻² (266.4F/g at 0.5 A g⁻¹ current density) with the 2H-MoS₂@SG electrode and 247.4 mF cm⁻² at 10 mA cm⁻² (190.31F/g at 0.5 A g⁻¹ current density) with the SG10 electrode. These values were measured at charge–discharge current rates of 10 mAcm⁻² in a 1.0 M H₂SO₄ electrolyte. Moreover, the capacitive behavior of this electrode was tested over 5000 cycles, showing a capacitance retention of more than 99.2 % at the end of the 5000 cycles. 2H-MoS₂@SG electrodes shows a high coulombic efficiency of 100 % over 5000 cycles at 0.5 A g⁻¹.