Solvent effects on the electrochemical performance of few layered MoS2 electrodes fabricated using FTO substrates

Abstract

Owing to its exceptional structural, electrical, and optical features, Molybdenum disulphide (MoS₂), a two-dimensional (2D) layered material with tuneable bandgap, finds its application in electrochemical supercapacitors for superior energy and power density. Because of their low toxicity and long-term energy storage, the development of MoS₂-based supercapacitors is inevitable. The study of solvent effects on the electrochemical performance of a few layered MoS₂ using FTO substrates is done for the first time to the best of our knowledge. Exfoliating bulk MoS₂ powder in different solvents with variable surface tensions such as Ethanol, Ethylene Glycol (EG), Dimethylformamide (DMF), and Dimethyl Sulfoxide (DMSO) results in the formation of few-layered MoS₂ structures. The sample’s structural, optical, and electrochemical behaviours are investigated using x-ray diffraction (XRD), atomic force microscopy (AFM), UV spectroscopy, Fourier transform infrared (FTIR), cyclic-voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). XRD confirms the formation of a 2D MoS₂ film with (002) planes and the optical investigation revealed the variation of layer-dependent bandgap with solvents. We observe both faradaic and non-faradaic charge storage mechanisms in the samples and demonstrate a superior pseudocapacitive behaviour for MoS₂ in DMF with a maximum specific capacitance of 34.25 F g⁻¹ at a current density of 1 A/g.