WS₂ Nanoflowers as Efficient Electrode Materials for Supercapacitors

Abstract

Supercapacitors are considered as the next‐generation energy storage devices due to their unique performance features. Properties such as large surface areas, high theoretical capacitance, and occurrence of efficient redox reactions at their surfaces make 2D WS2 transition metal dichalcogenides propitious constituents in energy storage devices. Herein, the synthesis of WS2 nanoflowers by a facile hydrothermal technique is reported. Free‐standing flexible supecapacitor electrodes are fabricated by the deposition of the WS2 nanoflowers over flexible conducting carbon fabric substrate. The electrochemical performance of the as‐prepared material is evaluated in a symmetric two‐electrode configuration. The WS2 symmetric capacitor delivers a significant specific capacitance of 119 F g−1 at 1 A g−1 current density. The device exhibits outstanding stability and nearly 100% capacitance retention after 10 000 charge–discharge cycles.

A study on the effect of phase conversion of tungsten nanostructures on their electrochemical energy storage performance

“…Two dominant peaks were observed at 347 ± 2 cm −1 and 415 ± 2 cm −1 corresponding to the in-plane and out-of-plane vibration of the WS 2 . 30,32…”

“…Also the peak observed at 452 cm −1 suggests the confirmation of the existence of the S–S stretching vibrations of WS 2 . 32,35,46,47…”

“…The existence of an immense quantity of redox-active regions will contribute to better conductivity for WS 2 , thereby improving the electrochemical performance of the electrode material. 32…”

“…The hysteresis loop also confirms that all three electrode materials were mesoporous in nature. 32,41…”

“…The storage mechanism of WS 2 can be explained by using equations 6 and 7, 32 WS 2 + K + + e − ⇔ WS––SK (faradaic)(WS 2 ) surface + K + + e − ⇔ (WS 2 ––K + ) surface (non faradaic)…”