Preparation And Modification Of MoS₂ Anode Material For Lithium Ion Batteries

Lithium-ion batteries are widely used in consumer electronics because of their high energy density,long life and environmental friendliness.As one of the core materials of lithium-ion batteries,anode materials play a vital role in new energy lithium-ion batteries.The research of high-capacity MoS2 anode materials has become one of the most active segments of current lithium-ion batteries.However,MoS2 anode materials also have some shortcomings,such as poor conductivity,easy agglomeration and volume expansion during charge and discharge,which impedes the wide application of MoS2 anode materials in lithium ion batteries.This thesis focuses on MoS2 materials,further enhances electrochemical performance and explores related energy storage mechanisms in different ways.The research contents of this thesis are as follows:(1)Firstly,the multi-stage structure of MoS2 was designed by theoretical calculation.The primary structure of Mo-terminated MoS2 and the crumpled structured MoS2 were synthesized by the modified hydrothermal method.It was found by electrochemical tests that the crumpled structure is superior to the primary structure in terms of specific capacity,rate performance and cycle stability.The in situ mechanical compression of the crumpled MoS2 revealed that it difficult to agglomerate and collapse during extrusion,resulting in a decrease in volume expansion during charge and discharge.It found that the crumpled MoS2 exhibited a superior specific capacity of 1754 mAh/g at 1 A/g and over 83%after 200 cycles,indicating that the multi-stage structure design can enhance the electrochemical performance of MoS2.(2)Secondly,stoichiometric ratio of MoS2 was synthesized by Mo and S ratio control.The electrochemical properties at room temperature and low temperature were studied under different electrolyte ratios.It was found that this structure of MoS2 was exhibited an inferior the capacity retention rate of 20%at 0.1 A/g and after 100 cycles at room temperature.And the capacity retention rate was 64%after 50 cycles of 0.5 A/g at low temperature.(3)Finally,MoS2/RGO nanocomposites were prepared by hydrothermal method.The material performance,which shows excellent the specific capacity of 1754 mAh/g at 0.1 A/g over 98%after 200 cycles at room temperature.Also,the specific capacity remains at 544.5 mAh/g at 0.2 A/g and over 84.9%after 100 cycles at low temperature,indicating it was a promising electrode material.