Novel hydrothermal synthesis of time-variant tungsten disulfide electrode material for high-performance supercapacitors

Layered nanospheres of tungsten disulfide (WS2) were synthesized by a simple one-step hydrothermal technique at various periods (3, 6, and 9 h) for high-performance supercapacitors (SCs), and their corresponding crystallographic phases and the structural and morphological characteristics were analyzed by X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The WS2-6h electrode possessed dense clouds of spherical nanoparticles evenly distributed on the Ni foam surface, creating clear pathways that enhanced the mobility of electrons/ions. Electrochemical studies were conducted in a 3 M KOH electrolyte with a three-electrode system, and the energy storage behavior was illustrated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electron impedance spectroscopy. The CV and GCD results confirmed that the fabricated WS2-6h electrode exhibited battery-type behavior. Electrochemical studies revealed that the WS2-6h electroactive material exhibited an enhanced specific capacity of 102.909 mA h g(-1) at 1 A g(-1), a rate capability of 87.68%, and excellent cycling stability of 98.26% after 4000 cycles. The remarkable electrochemical features, structure, and morphology indicate that the as-synthesized WS2-6h electrode is a promising electrode for highperformance SCs.