【作者】 张杰；

【导师】 王太宏；

【作者基本信息】 湖南大学 ， 凝聚态物理， 2009， 硕士

【摘要】 近年来,随着信息时代多功能便携式和高能量电子设备的需求日益增长,以及为减小环境污染而提出的使用电动汽车的迫切要求,开发高比容量、高稳定性、高安全性、长寿命、低成本的新型锂离子电池负极材料显得尤为迫切。本文在综合评述了锂离子电池及其负极材料研究进展的基础上,选取锡(Sn)基氧化物负极材料作为研究对象,采用静电喷雾技术,在不锈钢基片上制备了不同工艺参数的SnO2薄膜及其复合薄膜。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等技术和设备,以及循环伏安(CV)、恒电流充放电等电化学测试方法,重点研究了制备方法、工艺参数对SnO2薄膜及其复合薄膜的形貌及电化学性能等影响,为利用静电喷雾技术开发新型的锡基氧化物薄膜负极材料提供了理论依据和关键的制备技术。本文系统地研究了溶剂、衬底温度和液体流速、电压等工艺参数对SnO2薄膜的结构、形貌及电化学性能的影响。对这些工艺参数的优化结果表明:乙醇、乙二醇和丙二醇三种溶剂,衬底温度为250℃,液体流速为2mL/h,电压为14kV获得的SnO2薄膜具有最佳的综合性能。该条件下制得的薄膜表面均一、多孔网状、无裂痕,首次放电容量为1276mAh/g,经100次循环后,容量仍然保持在416mAh/g,具有较好的电化学性能。在此基础上,本文还研究了二氧化硅含量对SnO2-SiO2复合薄膜形貌和电化学性能的影响。随着二氧化硅含量的增加,SnO2-SiO2复合薄膜电极的首次嵌锂容量逐渐升高,首次库仑效率逐渐升高,首次容量损失呈减少趋势,SnO2-SiO2复合薄膜的100次循环后容量为364mAh/g:其库仑效率基本维持在98%,SnO2-SiO2复合薄膜结构有利于锂离子嵌脱,能够提供较多的嵌锂通道和嵌锂位置,并利用二氧化硅抑制SnO2电极的体积膨胀,在一定程度上提高了薄膜电极的循环性能。更多还原

【Abstract】 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.更多还原