钾离子电池用超分散少层MoSe_(2)负极材料的实验设计

Ultra-dispersed low-layer MoSe_(2) materials for potassium ion batteries

该文设计了钾离子电池用超分散MoSe_(2)负极材料合成的研究型综合实验。该实验以层间作用力较弱的MoSe_(2)为研究对象,提出用有机小分子在MoSe_(2)层间“扩层-剥离”及MoSe_(2)在碳质骨架中诱导组装这两种策略来优化MoSe_(2)负极材料的设计原则。超分散的MoSe_(2)材料协同碳质骨架的空间-化学双重限域机制,可有效解决电极材料体积膨胀、易粉化、活性组分脱落等关键问题,进而获得高容量、高倍率、长循环的储钾负极材料。该综合实验将为高性能储钾负极材料的设计提供一定理论依据,同时有助于培养学生综合运用所学理论知识进行科学研究和解决实际问题的能力。

[Objective]A new research experiment is designed for the synthesis of ultra-dispersed MoSe_(2) anode materials for use in potassium ion batteries.In this experiment,MoSe_(2) with weak interlayer force is considered the research object,and two strategies are proposed to integrate the design principles of MoSe_(2) anode materials.The first strategy involves the expansion and stripping of organic small molecules between MoSe_(2) layers,and the other involves the induced assembly of MoSe_(2) in the carbon skeleton.The ultra-dispersed structure of MoSe_(2) material,coupled with the spatial-chemical dual confined mechanism of the carbon skeleton,helps address key problems such as electrode volume expansion,pulverization,and active component shedding.By integrating the above experimental design,the electrode material with high capacity,high rate,and long cycle can be obtained.[Methods]This experimental design involves two main steps:1.To improve the structural stability of layered MoS_(2) nanosheets,the MoS_(2) is first combined with a carbon skeleton material.The carbon skeleton that is prepared using the salt crystal template method offers benefits such as large specific surface area,abundant pore structure,and adjustable surface chemical environment.Thus,it is an excellent carrier of active materials for electrode materials.Under solvothermal conditions,MoS_(2) nanosheets can be self-loaded and uniformly dispersed in a carbon skeleton with abundant porous cavities.2.To further improve the electrochemical performance of the MoS_(2) material,small organic molecules are inserted into the MoS_(2) layer structure to effectively expand the layer spacing of MoS_(2).Small organic molecules with appropriate molecular size are selected,and according to their specific functional groups,they can be easily inserted into the Se-Mo-Se molecular layers under solvothermal conditions.The two aforementioned methods can effectively promote the rapid potassium storage behavior of the electrode material on the level of electrochemical reaction kinetics.[Results]The morphology of the ultra-dispersed MoSe_(2)@carbon skeleton material helps retain the original frame structure of the carbon skeleton,and there is no obvious agglomeration phenomenon.In contrast,pure MoSe_(2) materials exhibited obvious agglomerations,forming tight nanoclusters.From the high-resolution TEM images,it was observed that the pure MoSe_(2) material exhibited clear lattice fringes,and more than 10 layers of Se-Mo-Se molecular layers are tightly stacked,with a layer spacing of approximately 0.67 nm.In the ultra-dispersed MoSe_(2)@carbon skeleton material,the MoSe_(2) is stripped to 2–5 Se-Mo-Se molecular layers,and the layer spacing is 0.82 nm.The XRD and Raman data also confirm that the ultra-dispersed MoSe_(2)@carbon skeleton material exhibits a relatively low crystallinity,its layer spacing is also increased,and the number of Se-Mo-Se molecular layers is reduced.These results are consistent with the TEM data.The electrochemical data also showed that the ultra-dispersed MoSe_(2)@carbon skeleton material exhibited a significant improvement in terms of capacity,rate characteristics,and cyclic stability.[Conclusions]The good synergistic mechanism of carbon-skeleton-induced assembly and organic small molecule expansion can ensure the good structural stability of MoSe_(2) materials.Additionally,it can improve the reaction kinetics characteristics of materials.This comprehensive experiment will provide a theoretical basis for the design of high-performance potassium ions storage anode materials and help students develop the ability to comprehensively apply theoretical knowledge in scientific research and solve practical problems.