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.