The practical application of Lithium–Sulfur batteries largely depends on highly efficient utilization and conversion of sulfur under the realistic condition of high-sulfur content and low electrolyte/sulfur ratio. Rational design of heterostructure electrocatalysts with abundant active sites and strong interfacial electronic interactions is a promising but still challenging strategy for preventing shuttling of polysulfides in lithium–sulfur batteries. Herein, ultrathin nonlayered NiO/Ni₃S₂ heterostructure nanosheets are developed through topochemical transformation of layered Ni(OH)₂ templates to improve the utilization of sulfur and facilitate stable cycling of batteries. As a multifunction catalyst, NiO/Ni₃S₂ not only enhances the adsorption of polysulfides and shorten the transport path of Li ions and electrons but also promotes the Li₂S formation and transformation, which are verified by both in-situ Raman spectroscopy and electrochemical investigations. Thus, the cell with NiO/Ni₃S₂ as electrocatalyst delivers an area capacity of 4.8 mAh cm⁻² under the high sulfur loading (6 mg cm⁻²) and low electrolyte/sulfur ratio (4.3 μL mg⁻¹). The strategy can be extended to 2D Ni foil, demonstrating its prospects in the construction of electrodes with high gravimetric/volumetric energy densities. The designed electrocatalyst of ultrathin nonlayered heterostructure will shed light on achieving high energy density lithium–sulfur batteries.

The development of magnetic two-dimensional (2D) materials in its infancy has generated an enormous amount of attention as it offers an ideal platform for the exploration of magnetic properties down to the 2D limit, paving the way for spintronic devices. Due to the nonnegligible advantages including time efficiency and simplified process, the facile bottom-up chemical vapor deposition (CVD) is regarded as a robust method to fabricate ultrathin magnetic nanosheets. Recently, some ultrathin magnets possessing fascinating properties have been successfully synthesized via CVD. Here, the recent researches toward magnetic 2D materials grown by CVD are systematically summarized with special emphasis on the fabrication methods. Then, heteroatoms doping and phase transition induced in CVD growth to bring or tune the magnetic properties in 2D materials are discussed. Characterizations and applications of these magnetic materials are also discussed and reviewed. Finally, some perspectives in need of urgent attention regarding the development of CVD-grown magnetic 2D materials are proposed.

Two-dimensional layers of metal dichalcogenides have attracted much attention because of their ultrathin thickness and potential applications in electronics and optoelectronics. Monolayer SnS₂, with a band gap of ~2.6 eV, has an octahedral lattice made of two atomic layers of sulfur and one atomic layer of tin. Till date, there have been limited reports on the growth of large-scale and high quality SnS₂ atomic layers and the investigation of their properties as a semiconductor. Here, we report the chemical vapor deposition (CVD) growth of atomic-layer SnS₂ with a large crystal size and uniformity. In addition, the number of layers can be changed from a monolayer to few layers and to bulk by changing the growth time. Scanning transmission electron microscopy was used to analyze the atomic structure and demonstrate the 2H stacking poly-type of different layers. The resultant SnS₂ crystals is used as a photodetector with external quantum efficiency as high as 150%, suggesting promise for optoelectronic applications.