Preparation And Electrochemical Properties Of Tin Dioxide-based Composites As Anode Materials For Lithium-ion Batteries

With the sharp increase in the number of vehicles such as ships and automobiles,the large consumption of traditional energy sources,and the problem of environmental pollution have become increasingly serious.It is imminent to develop new green energy storage devices to be used in the application engineering of ships and automobiles.Lithium-ion batteries have many advantages such as high energy,density,long cycle life,no memory effect,wide operating temperature range,and environmental friendliness.They have successfully become the main power source for portable electronic equipment.It also has a broad application prospect and research value in the field of vehicle.The anode material is one of the core materials of the lithium-ion battery.The optimization of the anode material has a greater effect on improving the overall performance of the lithium-ion battery.Due to its high theoretical capacity and abundant reserves,SnO2 is considered to be one of the most promising anode materials.However,SnO2 has poor conductivity,and the large volume expansion during charging and discharging causes the material to pulverize and agglomerate,resulting in poor cycle stability.In this paper,nanostructured SnO2 was prepared by changing the process conditions with hydrothermal method,and the effects of hydrothermal time and hydrothermal temperature on its micromorphology and electrochemical performance were studied and analyzed.In order to further improve the performance,on this basis,the method of composite with biomass carbon and other carbon sources and metal oxide coating is adopted to improve its conductivity and cycle stability.The main research conclusions of this paper are as follows:(1)Using SnCl2 2H2O as a tin source,hydrothermal method was used to prepare SnO2 with different nanostructures by controlling the reaction temperature and reaction time.It was found that SnO2 nanospheres were prepared at 180? for 12 h.At a current density of 200 mA/g,the specific discharge capacity after 48 cycles of charge and discharge is 485.6 mAh/g.(2)The prepared SnO2 powder was compounded with graphene,carbon nanotubes,and porous amorphous carbon self-made using a corncob core as a biomass template.The results showed that:under 200 mA/g current density,100 charge After the discharge cycle,the discharge specific capacity and cycle stability were improved to different degrees,of which the graphene improvement effect is the most obvious.The analysis believes that this is related to the addition of graphene to greatly improve the internal resistance of the electrode.(3)The prepared SnO2 nanospheres were coated with Fe2O3 by hydrothermal method to obtain SnO2@Fe2O3 composite material.The study found that SnO2@Fe2O3-10 showed very excellent cycle stability and rate performance.After 100 charge-discharge cycles at a current density of 200 mA/g,the specific discharge capacity can still reach 680 mAh/g.