Time-dependent synthesis of tungsten disulfide for flexible supercapacitors

Abstract

Tungsten disulfide (WS2) with various nanostructures was synthesized for times ranging from 6 to 72 h, using a simple and easy hydrothermal technique, for high-performance supercapacitor applications. The synthesized WS2 for 24 h (WS2–24), among other synthesized WS2, exhibited flower-like structures, composed of numerous nanosheets, demonstrating superior electrochemical properties in terms of electrochemical surface area, charge transfer resistance, specific capacitance, and rate capability. In addition, WS2–24 was coated on a flexible activated carbon cloth substrate to make flexible electrodes and assemble a flexible symmetric supercapacitor with a gel electrolyte. The flexible supercapacitor exhibited a specific capacitance of 262.5 F g−1 at 1 A g−1 with an energy density of 23.6 Wh kg−1 and a power density of 802 W kg−1. It also showed excellent capacitance retention of 94.5 % and a Coulombic efficiency of 86.4 % after 5000 cycles. The remarkable electrochemical properties of the synthesized WS2 materials highlight them as highly effective active materials for high-performance supercapacitor electrodes.