Preparation And Electrochemical Properties Of Molybdenum Disulfide Matrix Composites

Lithium-ion batteries have many advantages,such as portable,environmentally friendly and high energy density.Therefore,lithium-ion batteries have been widely concerned and applied in portable electronic devices,electric vehicles and other fields.Anode materials are a key component of lithium-ion batteries,which play a vital role in the electrochemical performance of lithium-ion batteries.Molybdenum disulfide(MoS2),as a typical layered transition metal binary compound,has a similar structure to graphene.It consists of three atomic layers(S-Mo-S),assembled by weak van der Waals force interaction,and has a high theoretical specific capacity(669.7 mAh/g).This kind of graphene structure of molybdenum disulfide is very advantageous to the intercalation and removal of lithium ions because of its super-large interlayer spacing,and the volume of molybdenum disulfide does not change much during this process.In this paper,molybdenum disulfide was used as a negative material in lithium/sodium ion batteries after modification,and its electrochemical performance was also studied.The research contents of this paper are as follows:(1)since graphite negative electrode is unable to meet the demand of high-performance lithium-ion batteries,graphene nanosheets and molybdenum disulfide nanosheets are used to crosslink the three-dimensional porous aerogel structure into lithium / sodium ion battery anode.In addition,the effects of different substrates on the electrochemical performance of lithium batteries were also investigated by loading graphene and molybdenum disulfide on different substrates.In the aerogel material,the conductivity of molybdenum disulfide can be improved obviously by introducing graphene,and the contact resistance of electrode material and substrate can be reduced by using new type of non adhesive substrate.The material preparation method used in this paper is simple and conducive to large-scale production.Therefore,the aerogel material prepared has good commercial application prospects.(2)Considering that the contact between graphene and molybdenum disulfide nanosheets still has a blind spot of poor conductivity,it is expected to introduce nano-metal particles to improve the conductivity of graphene and Molybdenum Disulfide Composites so as to improve the electrochemical properties of the materials.Molybdenum disulfide and graphene composites(MoS2/GS/Fe)adhering to nano-iron particles were prepared by water bath heating method.The prepared composite will form a foam structure with porous materials,enabling lithium ion to be embedded and released rapidly.The adhesion of nanoscale iron particles significantly improved the conductivity of foam materials,and the enhancement of electrical conductivity accelerated the transmission rate of ions and electrons during charging and discharging.When testing the lithium storage properties of foam materials,the first charge and discharge capacity of the MoS2/GS/Fe composite material is 1967,1437mAh/g at the current density is 100mA/g.The first coulombic efficiency is 73.1%..After 100 times constant current charge discharge cycle,the specific capacity can reach 1557mAh/g,the capacity retention rate reaches 108.4%,can be considered as the material is activated during the cycle,which further proves the excellent cycle stability of the foam material.