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

Abstract

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