The Research Of Tin-based Oxides For Li-ion Battery Anodes

During recent years, with the development of electric vehicles for decreasing environment pollution and portable electronic devices, these is an interest in developing new electronic devices, there is an interst indeveloping new electrode materials with higher capacity, higher stability, higher safety and lower cost for lithium ion batteries. This thesis selected tin-based oxides materials as anode for lithium ion battery. Different types of SnO2 and SnO2 -SiO2 compsite films were prepared by electrostatic spray deposition (ESD) method. The structure and electrochemical properties of films with different deposition method and technology parameters are investigated by electrochemical methods in combination with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), transmission Electron Microscopy (TEM). The new approach and work results to prepare a new type of tin-based oxides films anode materials by ESD.In this thesis, the film performance has been studied as a function of preparation condition, i.e. the solvent, the deposition temperature, the deposition rate and voltage. The thin films obtained from the optimal fabrication condition (ethanol-glycol-propanediol solvents, the deposition temperature of 250℃, the deposition rate of 2mL/h, and the voltage of 14kV) were homogeneous, reticular porous, crack-free. The first discharge capacity is 1276mAh/g, and the reversible capacity retained 416mAh/g after 100 cycles.The different SiO2 content of SnO2 -SiO2 compsite has been studied. With the increase of the SiO2 contents, the SnO2 -SiO2 compsite electrode of the first lithium intercalation capacity and the first cycle efficiency gradually increased, the first capacity loss declined. The micro-structure and electrochemical properties of SnO2 -SiO2 compsites have been studied. It has been found that the reversible capacity retained 364mAh/g after 100 cycles. For the second cycle, the charge and discharge efficiency is 98%, which can be astribed to the mixable SiO2 provides a transmission path for lithium ion insertion. Moreover, the SiO2 have an enfored function to tin body and decreased the breaking uo of electrodes.