Preparation And Electrochemical Properties Of Molybdenum Based Compound Composites

Facing the increasingly serious global energy crisis and environmental problems,the development of clean renewable energy materials and their devices is increasingly urgent.The superior performance of the energy storage device is closely related to the performance of the electrode material.Transitional metal dihalide compounds(TMDs)and transition metal carbides(TMCs)have the characteristics of large surface volume and more surface active sites.These characteristics give them good kinetic properties and have attracted wide attention due to their great energy storage and conversion potential.This article mainly molybdenum base compound composite material as the research object,analyses the chemical reactivity and electrochemical performance,on this basis,successful design two can be used in lithium-ion batteries was prepared on the composite material.The composite material was characterized by XRD,XPS,SEM and TEM,and through electrochemical tests prove that the material has excellent electrochemical performance,extended the second transition metal halogen compounds and transit ion metal carbides in the application in the field of lithium-ion batteries.The specific work contents are as follows:(1)Using MoO₃ hexagonal prism prefabricated by hydrothermal method as regulator,two kinds of flower Mo Se₂@NC composites with different morphologies and sizes were prepared by combining self-assembly and heat treatment.The composite material was characterized by XRD,XPS,SEM and TEM,and was prepared into a button cell for electrochemical analysis.It is found that the Mo Se₂/NC SNCs composites with particle size of about 500 nm have higher cycle stability and better rate performance.It has a high rate capacity of 480 m Ah/g at the current density of 4.0A/g.At the current density of 2.0 A/g,it still has a reversible capacity of 501 m Ah/g after 320charge-discharge cycles.Therefore,Mo Se₂/NC SNCS composites have excellent rate performance and long cycle life,and are expected to become one of the promising anode candidates for the construction of lithium-ion batteries.(2)Using the replacement reaction of molybdenum chloride and sodium sulfide to obtain molybdenum sulfide,and using this as a springboard to further carbonize with glucose to form Mo₂C@Na Cl@C composite material,and then using sufficient amount of deionized water to conduct soaking and stirring treatment of Mo₂C@Na Cl@C composite material to get pure composite material.By adjusting the proportion of molybdenum chloride,sodium sulfide and glucose,Mo₂C@C composites with different shape characteristics and load loads were obtained.The characterization methods of composite materials include XRD,SEM and TGA tests,and then prepared into a button cell for electrochemical analysis.It is found that Mo₂C(45.2%)@C composite has higher structural stability and maintains a high capacity of 295 m Ah/g after 1000 cycles at the current density of 2A/g.In addition,it still has a reversible capacity of 405 m Ah/g at a current density of 4A/g.Therefore,it can be seen that this material has excellent rate performance and long cycle life,and is expected to become one of the promising anode materials for the construction of lithium ion batteries.