The researchers found that tungsten disulfide (WS2) can be converted into a direct semiconductor with a band gap of 2.1 eV by controlling the chemical composition and number of layers due to the quantum confinement effect. In addition, WS2 has better saturable absorption properties than graphene and carbon nanotubes in the near- and mid-infrared bands. Due to these excellent properties, it is increasingly being used in laser saturable absorbers (SAs).

Tungsten disulfide (WS2) is promising electrocatalysis with a layered structure with adjustable electrical properties and exposed edges that can act as the active center. It is mainly used as an electrocatalyst for hydrogen evolution reactions. The surface of WS2 is inert; however, the catalytic activity of WS2 occurs at the lamellar edges, which determines the overall catalytic performance. In order to improve the catalytic effect of WS2, the electrolyte must be in complete contact with the WS2 layer.

Bulk tungsten disulfide (WS₂) can be stripped by physical and chemical methods, which are classified as mechanical and stripping method, and lithium-ion intercalation method. In recent years, in order to obtain large-area, high-quality monolayer tungsten disulfide films, researchers have tried to grow monolayer tungsten disulfide films on ingot substrates and then exfoliate them by atomic or molecular intercalation methods.

Two common methods for preparing tungsten disulfide (WS₂) films by chemical methods are chemical vapor deposition (CVD) and hydrothermal growth of single-crystal tungsten disulfide from aqueous solutions under high temperature and pressure conditions. CVD is the most common method used to prepare tungsten disulfide. The CVD method involves a reaction process in which a gaseous precursor reacts chemically on a solid surface to produce a solid deposit.

Owing to unique physical and chemical properties, transition metal dichalcogenides (TMDs) attract research interest. Among the family of TMDs, tungsten disulfide (WS₂) has a unique band structure due to its semiconductor properties; i.e., its broadband spectral response characteristics, ultra-fast bleaching recovery time, and excellent saturable light absorption.

The atomic structure of tungsten disulfide (WS₂) consists of a stack of three layers formed by a transition metal layer (W atom) sandwiched between two S-atom layers, each with a hexagonal lattice structure. In the three-layer stack, W and S atoms are bonded together by strong ion-covalent bonds. WS₂ formed by these three layers is held together by weak van der Waals interactions, which allow mechanical exfoliation of the WS₂ layer. In the bulk phase, polymorphism is a unique feature of TMDs.

Alloys are metals made by combining two or more metallic elements, primarily to provide greater strength or corrosion resistance. The tungsten alloy family has many industrial applications due to its strength. Tungsten offers a unique contribution because it imparts exceptional strength, corrosion resistance and other useful properties to base metals. In addition to being an excellent alloying element, tungsten can also serve as the basis for its own alloys, and this article will focus on the basic categories of these tungsten alloys. Below are some details on the 3 most common tungsten alloys widely used in industry. Their properties and applications will also be introduced.

The current applications on WS₂ nanomaterials still face challenges and should be investigated in depth in the following aspects. Firstly, the study mechanism of HER needs to be deepened and clarified in terms of the fundamental properties of WS₂. Advanced characterization methods, such as in situ techniques, can be combined to analyze the structural changes of the material during the catalytic process and reveal the catalytic process of WS₂-based nanomaterials, especially electrocatalysis.

Recently, researchers demonstrated a specific capacitance of 398.5 F.g^-1 for sheet tungsten disulfide anode materials. However, the performance of these materials remains unsatisfactory. Encouragingly, Nagaraju et al. synthesized WS₂ nanoparticles used as supercapacitor electrode materials, which provided a high capacitance value of 1439.5 F.g^-1 at a current density of 5 mA.cm^-2 and maintained excellent cycling stability of 77.4% after 3000 cycles. This result suggests that WS₂ can be considered a promising candidate for supercapacitor electrode materials.

Tungsten disulfide possesses a much larger interlayer spacing of 0.62 nm than that of graphite (0.34 nm). This would be very favorable for the reversible process of Na⁺ intercalation/de-intercalation, making WS₂ a promising anode material for sodium-ion batteries (SIBs). For example, Liu et al. reported WS₂ nanowires (NWs) with an expanded interlayer spacing of 0.83 nm.