锂离子电池锡基复合负极与富锂层状正极材料的制备与电化学性能表征

发布时间：2018-11-21 07:38

【摘要】：近年来,由于锂离子电池具有能量密度高、比容量高和质量轻等优点,在手机、笔记本电脑等小型电子产品中得到了广泛的应用。随着电动汽车与电动工具等产业的迅猛发展,迫切需要开发具有更高功率密度和能量密度、更长循环寿命的锂离子电池作为动力支持。作为可逆充放电的主体,电极材料是新型锂离子电池成功开发的关键。本论文的研究内容集中于新型锂离子电池负极二氧化锡纳米材料和正极富锂层状材料的合成、优化及电化学性能表征。论文第一章中主要介绍了锂离子电池的组成结构、工作原理和发展历史,并展望了锂离子及动力型电池的应用前景。文中首先分别对锂离子电池的正负极材料进行了总体概述,然后着重论述了两种电极材料(金红石型SnO2负极材料和富锂正极材料xLi2MnO3-(l-x)LiMO2(M=Co, Ni, Mn))的结构、储锂机理、合成以及改性的研究现状。论文在第二章简要介绍了实验工作中所涉及的实验试剂、方法和仪器。此外,还特别介绍了2025型扣式电池的组装方法,以及常用的材料结构、形貌和成分等表征手段和电化学测试方法。论文第三章中,采用氧化石墨烯作为氧化剂一步快速水热法合成了SnO2/石墨烯纳米复合材料,通过调节氧化石墨烯的配比,成功地制备出SnO2/SnO两相复合物和纯相SnO2,并研究了氧化石墨烯与亚锡离子比例对最终产物的形貌、结构和电化学性能的影响。结果表明,当氧化石墨烯质量分数为32%时,合成的SnO2/石墨烯纳米复合材料表现出了高的循环稳定性,经过90次循环后,放电比容量仍然保持在525mAh/g,平均容量损失仅为0.3%。论文第四章中,采用一步快速燃烧法合成了富锂正极材料,并分别应用有机酸尿素和柠檬酸作为燃料,系统考察了两种燃料对所制备材料的结构、形貌和电化学性能的影响；同时,对应用不同燃料所制备的材料的电化学性能差异的原因进行了细致分析。结果表明,尿素燃烧法合成的富锂正极材料Li[Li0.2Mn0.54Ni0.13Co0.13]O2综合电化学性能最佳。0.1C电流倍率下首次放电比容量为264.6mAh/g,1C下最高放电比容量为167.5mAh/g,经过100次循环后容量为150.3mAh/g,保持率达90%。
[Abstract]:In recent years, lithium-ion batteries have been widely used in small electronic products such as mobile phones, laptops and other small electronic products because of their advantages of high energy density, high specific capacity and light quality. With the rapid development of electric vehicles and power tools, it is urgent to develop lithium ion batteries with higher power density and energy density and longer cycle life as power support. As the main body of reversible charge and discharge, electrode material is the key to the successful development of new lithium ion battery. This paper focuses on the synthesis, optimization and electrochemical characterization of novel anode tin dioxide nanomaterials and positively rich lithium layered materials for lithium-ion batteries. In the first chapter, the structure, working principle and development history of Li-ion battery are introduced, and the application prospect of Li-ion and power battery is prospected. In this paper, the cathode materials of lithium ion batteries are summarized, and the structure of two kinds of electrode materials (rutile SnO2 anode and lithium-rich xLi2MnO3- (l-x) LiMO2, Ni, Mn) are discussed. Research status of lithium storage mechanism, synthesis and modification. In the second chapter, the reagents, methods and instruments involved in the experiment are briefly introduced. In addition, the assembly method of 2025 type button battery, the usual characterization methods, such as structure, morphology and composition, as well as electrochemical measurement methods are also introduced. In chapter 3, SnO2/ graphene nanocomposites were synthesized by one step hydrothermal method using graphene oxide as oxidant. By adjusting the proportion of graphene oxide, SnO2/SnO two-phase composites and pure phase SnO2, were successfully prepared. The effect of the ratio of graphene oxide to tin oxide on the morphology, structure and electrochemical properties of the final product was studied. The results show that when the mass fraction of graphene oxide is 32, the synthesized SnO2/ graphene nanocomposites exhibit high cyclic stability. After 90 cycles, the discharge specific capacity remains at 525mAh/ g. The average capacity loss is only 0.3%. In chapter 4, Lithium rich cathode materials were synthesized by one step rapid combustion method. The effects of organic acid urea and citric acid on the structure, morphology and electrochemical properties of the materials were investigated. At the same time, the reasons for the difference of electrochemical properties of the materials prepared by different fuels were analyzed in detail. The results show that the lithium rich cathode material Li [Li0.2Mn0.54Ni0.13Co0.13] O2 synthesized by urea combustion has the best comprehensive electrochemical performance, and the first discharge specific capacity is 264.6 mAh/ g at 0.1C current ratio. The maximum discharge capacity at 1C is 167.5 mg / g, and after 100 cycles the capacity is 150.3 mg / g, and the retention rate is 90%.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912;TB33

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