Bulk Fabrication of WS₂ Nanoplates: Investigation on the Morphology Evolution and Electrochemical Performance

Two-dimensional layered chalcogenide WS₂, similar to graphene, is considered to be very interesting for materials scientists. However, to make it a useful material platform, it is necessary to develop sophisticated synthesis methods to control its morphology. In this paper, we present a simple approach to prepare various morphologies of WS₂ nanostructures by direct thermal evaporation of WO₃ and S powders onto Si substrates sputtered with W film without using any nanostructured W-contained precursors and highly toxic sulfide gases. This method can produce bulk quantities of pure hexagonal, horizontally grown WS₂ nanoplates, vertically grown nanoplates, and nanoplate-formed flowers simply by tuning the distance between the substrate and source powders. The synthesis mechanism and morphology evolution model were proposed. Moreover, when employed as a thin-film anode material, the Li-ion battery with as-prepared, vertically grown WS₂ nanoplates presented a rechargeable performance between 3 and 0.01 V with a discharge capacity of about 773 mAh/cm³ after recycling three times, much better than its already-reported counterparts with randomly distributed WS₂ nanosheet electrodes, but the battery with horizontally grown WS₂ nanoplates could not show any charge–discharge cycling property, which could be attributed to the different structures of WS₂ anodes for Li⁺ ion intercalation or deintercalation

Densities and Viscosities for the Ternary Mixtures of <i>n</i>‑Undecane (1) + Butylcyclohexane (2) + 1‑Pentanol (3) and Corresponding Binaries at <i>T</i> = (293.15 to 333.15) K

The actual composition is known to be highly responsible for the physical and chemical properties of a fuel. To understand the foundational physical properties of an aviation kerosene substitute mixture for hypersonic aircraft, n-undecane, butylcyclohexane, and 1-pentanol were used to construct a ternary system. The values of density (ρ) and viscosity (η) for the ternary system and three corresponding binaries were measured at temperatures T = (293.15 to 333.15) K and pressure p = 0.1 MPa. The Redlich–Kister equation was used to fit the excess molar volumes (VmE) and viscosity deviations (Δη) of the binary systems, while those of the ternary system were correlated with four semi-empirical formulas (Cibulka, Singh, Redlich–Kister, and Nagata–Tamura equations). The experimental results show that the VmE values of the three binary mixtures have a positive relationship with the mole fraction of nonpolar components, while Δη values have a negative relationship. The non-ideal behavior of mixtures is discussed from the perspective of molecular interactions and structural effects. This work provides data support and guidance for fuel compatibility research