It is meaningful to exploit copper sulfide materials with desired structure as well as potential application due to their cheapness and low toxicity. A low-temperature and facile solvothermal method for preparing three-dimensional (3D) hierarchical covellite (CuS) microspheres from an ionic liquid precursor [Bmim]2Cu2Cl6 (Bmim = 1-butyl-3-methylimidazolium) is reported. The formation of CuS nanostructures was achieved by decomposition of intermediate complex Cu(Tu)3Cl (thiourea = Tu), which produced CuS microspheres with diameters of 2.5-4 μm assembled by nanosheets with thicknesses of 10-15 nm. The ionic liquid, as an "all-in-one" medium, played a key role for the fabrication and self-assembly of CuS nanosheets. The alkylimidazolium rings ([Bmim](+)) were found to adsorb onto the (001) facets of CuS crystals, which inhibited the crystal growth along the [001] direction, while the alkyl chain had influence on the assembly of CuS nanosheets. The CuS microspheres showed enhanced electrochemical performance and high stability for the application in supercapacitors due to intriguing structural design and large specific surface area. When this well-defined CuS electrode was assembled into an asymmetric supercapacitor (ASC) with an activated carbon (AC) electrode, the CuS//AC-ASC demonstrated good cycle performance (∼88% capacitance after 4000 cycles) and high energy density (15.06 W h kg(-1) at a power density of 392.9 W kg(-1)). This work provides new insights into the use of copper sulfide electrode materials for asymmetric supercapacitors and other electrochemical devices.

3D ordered nanostructures assembled by 1D and 2D CuO building blocks dramatically improve the electrochemical performance for supercapacitors.

The optical properties of heavy metal-free quaternary CuZnInS3 QDs can be optimized by tuning the composition, which is promising for improving the efficiency of QDs-PEC hydrogen generation.

MoS2 nanotubes have received much attention due to their wide applications in various areas. However, the synthetic strategies to fabricate few-layer/single-layer nanosheet-assembled MoS2 nanotubes have rarely been developed. Herein, we have developed a hydrothermal route to synthesize three-dimensional (3D) nanosheet-assembled MoS2 nanotubes employing 1-n-butyl-3-methylimidazolium thiocyanate ([BMIM]­SCN) as a sulfur source and stabilizer. The obtained nanostructure with both advantages of tubular and nanosheets are able to cause the formation of some mesoporous structure, which are facilitate the insertion and extraction of lithium ions, the contact between the electrode and electrolyte, and the improvement of the mechanical stability of the electrode. These outstanding properties suggesting a potential application in high energy density lithium-ion batteries (LIBs), and that we believe that this simple approach can be applied to synthesize other transitional-metal chalcogenide 3D hollow structures.