Lithium ion storage ability, supercapacitor electrode performance, and photocatalytic performance of tungsten disulfide nanosheets

Abstract

Although tungsten disulfide (WS₂), an analogue of graphite, has long been pursued as a promising energy storage material due to its unique layered structure, structural changes, volumetric expansion and poor electronic conductivity have limited its practical use. Here, we report the synthesis of porous WS₂ composed of a few layered nanosheets (P-WS₂) using a simple and scalable hydrothermal method, as well as its electrochemical properties when used for a lithium storage electrode, a supercapacitor electrode, and a visible light active photocatalytic material. P-WS₂ as an anode for lithium-ion batteries showed a high specific capacity of 292 mA h g⁻¹ at a current density of 0.2C with excellent cycling stability over 100 cycles. The half-cell electrochemical assembly test demonstrated that P-WS₂ delivered 241.5 F g⁻¹ at a current density of 0.75 A g⁻¹ and showed excellent stability over 2000 consecutive charge–discharge cycles. P-WS₂ nanosheets exhibited 10 times higher photocatalytic activity than bulk commercial WS₂ (C-WS₂) for the degradation of Rhodamine B dye under visible light irradiation. The excellent performance of P-WS₂ is due to its sheet-like structure, porous characteristics, and high surface area.