Kai Yao,Zhanwei Xu,Zhi Li,Xinyue Liu,Xuetao Shen,Liyun Cao,Jianfeng Huang
Graphical Letting steam do the work : A grain-like MoS 2 is synthesized by sulfiding MoO 3 using a highly concentrated sulfur vapor. MoS 2 grows epitaxially on three lattice planes, giving rise to particulate MoS 2 coated with MoS 2 nanosheet. Such an architecture gives rise to good dispersity and sufficient distance between neighbors to accommodate the volume change associated with sodiation/desodiation and exhibits a high and stable capacity when used in a sodium-ion battery. MoS 2 is a promising anode material for sodium-ion batteries (SIBs) due to its attractive theoretical capacity and low cost. MoS 2 generally presents a sheet-like structure based on its (002) lattice plane; however, such a structure tends to result in agglomeration and stacking of the sheets that cannot accommodate volume expansion, resulting in poor cyclability. Herein, grain-like MoS 2 particulates (G-MoS 2 ) are synthesized by sulfiding MoO 3 in highly concentrated sulfur vapor, which results in epitaxial growth of MoS 2 in (002), (100), and (110) lattice planes, with the product consisting of MoS 2 particulates of about 300 nm coated with few-layered MoS 2 nanosheets. The unique G-MoS 2 architecture ensures good dispersion and sufficient distance to accommodate volume expansion during sodiation/desodiation, which effectively prevents stacking of MoS 2 , maintaining structural stability. When employed as the working electrode for SIB, G-MoS 2 delivers a high reversible capacity of 324 mAh g −1 at 0.5 A g −1 , retaining 312 mAh g −1 over 300 cycles with an average coulombic efficiency of 99.8 %. Even when G-MoS 2 is cycled at a high current density (2.0 A g −1 ), the retained capacity is 175 mAh g −1 after 400 cycles. Comparison with literature reveals that these capacities are among the more promising reversible values reported for pure MoS 2 .
Recently, the moiré superlattice structure (MSS) has garnered increasing attention thanks to its extensive research potential in condensed matter physics . However, how to create MSSs on non-van der Waals crystal plates is still elusive. In the present study, we propose a new method to prepare MSSs on the MoO 2 (010) surface by soaking MoO 2 in sulfur vapour at high temperature. MoO 2 is 2D non-layered materials and is prepared by annealing MoO 3 with sulfur vapour at 500 °C. The torsional modulation between two stacked monolayers is periodic, which provides additional freedom to change the material properties . Under sulfur vapour, the surface atoms of MoO 2 first change from monoclinic to tetragonal crystals, and the interlayer covalent bonds are broken at the same time. Then, the top layer and buffer layer atoms of MoO 2 form the original MSS, and the top layer continue to rotate into different twisted angles. Our work provides some inspiration and reference to the preparation of MSSs on the surface of the other 2D non-van der Waals crystals. In addition, we further compared the wettability of MSS@MoO 2 and ordinary MoO 2 powder. The results show that the surface of MSS@MoO 2 is strongly hydrophobic (approximately 140°), while that of ordinary MoO 2 is superhydrophilic (4.3°). Our results suggest that MSSs may be a potential application to change the surface wettability of materials.
危险品化学品经营许可证（带存储）