Study On Preparation And Electrochemical Properties Of Tin Dioxide And Its Nanocomposite Anode For Lithium Ion Battery

Tin dioxide (SnO2) is considered as an alternative anode material for lithium ionbatteries because of its relatively high theoretical gravimetric and volumetric lithiumstorage capacity. In order to reduce the volume of the expansion of SnO2, two kinds ofSnO2-based composites with new structure were prepared by the hydrothermal methodthat included that in situ growth of SnO2with different morphology on the surface ofcarbon materials with different dimension. The as-prepared products were characterizedby X-ray diffraction, scanning electron microscope and thermo gravimetric analyses. Theelectrochemical performance of SnO2-based composites were measured by galvanostaticcharge/discharge cycling, cyclic voltammetry and electrochemical impedancespectroscopy.The SnO2nanosheets grown on multi-walled carbon nanotubes were successfullysynthesized by hydrothermal method, in which the SnCl2·2H2O was used as Sn source.SEM observations shows crystalline SnO2nanoparticles are coated on the surface of theSWCNTs. Galvanostatic charge/discharge cycle display the reversible discharge capacitiesof SnO2/MCNTs nanocomposite are higher than that of113mAh/g for SnO2nanosheetsat the current densities of0.2C after20cycles. The charge transfer resistance is257.4,which is87.5lower than that of bare SnO2nanosheets; the exchange current density is24.94mA/g, which is6.33mA/g higher than that of bare SnO2nanosheets.The graphene was prepared by microwave from graphite oxide which wassynthesized by modified Hummers’ method. SnO2microspheres and SnO2nanorods/GNSnanocomposite were prepared by hydrothermal method, in which the SnCl4·5H2O and H2Owere used as Sn source and solvent, respectively. The discharge capacities of SnO2/GNSnanocomposite are higher than that of207mAh/g for bare SnO2nanorods at the currentdensities of0.2C after20cycles, which decreases with the increase of discharge currentdensity. After15cycles at current density of0.5C,1C,2C and5C, the discharge capacityof the SnO2/GNS nanocomposite anode is615mAh/g,582mAh/g,554mAh/g and417mAh/g, respectively, which is higher than that of bare SnO2nanorods. The charge transferresistance is227.6, which is120.9lower than that of bare SnO2nanorods; the exchange current density is28.20mA/g, which is9.8mA/g higher than that of bare SnO2nanorods.