Green hydrothermal synthesis of Mg-doped transition metal dichalcogenides using Camellia sinensis extract for enhanced energy storage

Tungsten disulfide (WS₂) is one of the new materials for energy storage applications that are transition metal dichalcogenides (TMDs). In this work, Camellia sinensis extract was used as a natural reducing and stabilizing agent in the green hydrothermal synthesis of magnesium-doped WS₂ (Mg-WS₂). The hexagonal structure and a modest increase in d-spacing (from 5.967 to 6.027 Å) were shown by X-ray diffraction (XRD), and improved porosity was demonstrated by Brunauer–Emmett–Teller (BET) surface area analysis. UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR) spectroscopy verified the optical spectrum’s blue shift and structural integrity, which suggested better electronic characteristics. The faradic behavior is validated by cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD) shows an elevated specific capacitance of 274.5 F/g at 2 A/g for the Mg-doped sample. Improved ion diffusion and a significant drop in charge transfer resistance (from 8.72 to 5.64 Ω) were shown by electrochemical impedance spectroscopy (EIS). Increased surface flaws, wider interlayer spacing, and improved conductivity brought about by magnesium doping are responsible for these enhancements. This study demonstrates Mg-WS₂ potential as a sustainable, high-performance electrode material for supercapacitor applications.

Graphical Abstract

Utilizing Camellia sinensis extract in green synthesis offers a sustainable, non-toxic, cost-effective, and eco-friendly alternative to conventional chemical methods.