Atomic Structure of Tungsten Disulfide

tungsten disulphide structure image

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.

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The 3 Most Common Tungsten Alloys—Its Properties & Applications

pure tungsten picture

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.

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Tungsten Disulfide for Electrode Materials of Supercapacitor

Electrochemical impedance spectroscopy spectra and diffusivity of lithium ions image

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.

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Challenges of Current Applications on WS2 Nanomaterials

Tungsten disulfide nanoparticles image

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.

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Tungsten Disulfide in Applications of Sodium-Ion Batteries

Electrochemical cyclability tests and HR-TEM of the WS2-r-GO and Sx-WS2-r-GO electrodes image

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.

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