Production Of MoS2 Nanosheets Research Articles

Toward layered MoS2 anode for harvesting superior lithium storage.

As a typical transition metal dichalcogenide (TMD), molybdenum disulphide (MoS2) has become one of the most promising anode materials for lithium-ion batteries (LIBs) due to its desirable electrochemical properties. But the development of commercial MoS2 is limited by the problem of agglomeration. Thus, the production of MoS2 nanosheets with few (<10) layers is highly desired but remains a great challenge. In this work, a facile and scalable approach is developed to prepare large-flake, few-layer (4–8) MoS2 nanosheets with the assistance of ultrasonics. Simultaneously, the as-prepared MoS2 nanosheets and commercial bulk MoS2 were analysed under multiple spectroscopic techniques and a series of electrochemical tests to understand the dependence of electrochemical performance on structural properties. When used as anode materials for LIBs, the obtained MoS2 nanosheets provide a reversible capacity of 716 mA h g−1 at 100 mA g−1 after 285 cycles, and demonstrated an excellent capacity retention rate of up to 80%. Compared with that of commercial MoS2 (14.8%), the capacity retention rate of our MoS2 nanosheets has a significant improvement. This work explored the ability of few-layered MoS2 nanosheets in the field of LIBs while suggesting the commercialization of the MoS2 by an ultrasonicated ball milling exfoliation technique.

Aqueous Cathodic Exfoliation Strategy toward Solution-Processable and Phase-Preserved MoS2 Nanosheets for Energy Storage and Catalytic Applications.

The production of MoS2 nanosheets by electrochemical exfoliation routes holds great promise as a means to access this two-dimensional material in large quantities for different practical applications. However, the use of electrolytes based on synthetic organic salts and solvents, as well as issues related to the unwanted oxidation and/or phase transformation of the exfoliated nanosheets, constitute significant obstacles that hinder the industrial adoption of the electrochemical approach. Here, we introduce a safe and sustainable method for the cathodic delamination of MoS2 that makes use of aqueous solutions of very simple and widely available salts, mainly KCl, as the electrolyte. Combined with an appropriate biomolecule-based solvent transfer protocol, such an electrolytic exfoliation route is shown to afford colloidally dispersed, oxide-free, and phase-preserved MoS2 nanosheets of high structural quality in considerable yields. The mechanisms behind the efficient aqueous delamination of the bulk MoS2 cathode are also discussed and rationalized on the basis of the penetration of hydrated cations from the electrolyte between its layers and the immediate reduction of the accompanying water molecules. An asymmetric supercapacitor assembled with a cathodic MoS2 nanosheet-single walled carbon nanotube hybrid as the positive electrode and activated carbon as the negative electrode delivered energy densities (e.g., 26 W h kg-1 at 750 W kg-1 in 6 M KOH) that were competitive with those of other MoS2-based asymmetric devices. When used as a catalyst for the reduction of nitroarenes, the present cathodically exfoliated nanosheets exhibited one of the highest activities reported so far with MoS2 nanostructures, the origin of which is accounted for as well. Overall, by facilitating access to this two-dimensional material through a particularly simple, efficient, and cost-effective technique, these results should expedite the practical implementation of MoS2 nanosheets in energy storage, catalysis, and beyond.