钠离子电池对苯二甲酸盐负极材料的研究

发布时间：2018-01-08 20:06

本文关键词：钠离子电池对苯二甲酸盐负极材料的研究　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：锂离子电池由于其高电压、高能量密度、低的自放电率以及优异的循环稳定性,在便携式电子产品的电源市场中独占鳌头。目前看来,锂离子电池可持续发展面临最大的问题就是锂资源的不足。因此,开发资源储存丰富、成本低廉的先进电池体系是解决未来大规模电能储存的必然出路。为了实现这个目标,自然将目光转移到了和锂元素同一个主族、性能比较接近的钠元素。一方面,地球上钠资源丰富,成本低廉;另一方面,由于钠的氧化还原电位较高,可使用一些安全性高的液体电解质体系,电池具有更高的安全性。如果用钠代替锂,开发出工作性能优良的钠离子电池,在大规模储能领域将拥有比锂离子电池更大的竞争优势。因此,探寻高比容量及优异循环性能的钠离子电池电极材料已成为目前电池领域的备受关注的课题。在众多的电极材料中,有机材料因具有廉价、容易提取、绿色环保等无机材料不具备的优势,最近引起了较大的关注。其中,共轭羰基类有机物由于具有比容量高、反应速率快以及种类繁多等优点而成为目前的研究热点。但是,目前对共轭羰基类有机物的研究仍然处在起步阶段,如羰基结构、晶体结构以及衍生物等因素与电化学性能之间的联系尚不清楚,因此本论文通过研究几种对苯二甲酸盐在钠离子电池中的电化学性能,旨在总结出一些结构与性能之间的内在联系,进一步深化共轭羰基类有机物在钠离子电池中应用的认识。本论文系统研究了对苯二甲酸盐体系对钠离子电池的电化学活性。首先利用酸碱中和反应和沉淀反应制备了对苯二甲酸锂(PTALi2)、对苯二甲酸镁(PTAMg)、对苯二甲酸钙(PTACa)、对苯二甲酸钡(PTABa)以及对苯二甲酸铝(PTAAl2/3),然后探究了上述对苯二甲酸盐在钠离子电池中的电化学性能,结果表明制备的对苯二甲酸盐对钠离子电池表现出优异的倍率性能和良好的循环稳定性。此外,通过对比PTALi2、PTACa和PTAAl2/3的电化学性能,发现随着对苯二甲酸盐中金属阳离子电荷量的增加,对苯二甲酸盐呈现出倍率性能和循环性能变优异的现象;通过对比PTAMg、PTACa和PTABa的电化学性能,发现随着对苯二甲酸盐中金属阳离子半径的增加,对苯二甲酸盐呈现出倍率性能和循环性能变优异的现象。在得知对苯二甲酸盐对钠离子电池具有电化学活性之后,本论文继续探讨了结晶水对对苯二甲酸盐电化学性能的影响。以PTAMg为研究对象,制备了含结晶水的对苯二甲酸(PTAMg·2H2O),并对比了PTAMg·2H2O和PTAMg的电化学性能,结果表明PTAMg·2H2O的电化学性能明显优于PTAMg。最后,鉴于对苯二甲酸盐导电性差,选择了碳包覆技术对其进行改性。本文选择了PTAMg为研究对象,以甘氨酸为碳源,对PTAMg实施碳包覆,结果表明:碳包覆能一定程度增加PTAMg的容量,并且添加质量比为15%碳源得到的碳包覆PTAMg具有最优异的电化学性能。
[Abstract]:Li-ion batteries are the leading power market in portable electronics because of their high voltage, high energy density, low self-discharge rate and excellent cycle stability. The biggest problem in the sustainable development of lithium-ion batteries is the shortage of lithium resources. The low cost advanced battery system is the inevitable way to solve the future large-scale electric energy storage. In order to achieve this goal, we naturally turn our attention to the same family as the lithium element. On the one hand, the earth is rich in sodium resources, low cost; On the other hand, because of the high redox potential of sodium, it is possible to use some liquid electrolyte systems with high safety, and the battery has higher safety if sodium is used instead of lithium. The development of sodium ion batteries with good working performance will have a greater competitive advantage than lithium ion batteries in the field of large-scale energy storage. To explore the high specific capacity and excellent cycling performance of sodium ion battery electrode materials has become a topic of great concern in the battery field. Among the many electrode materials, organic materials are easy to be extracted because of their low cost. Recently, the advantages of inorganic materials such as green environmental protection have attracted more and more attention. Among them, conjugated carbonyl organic compounds have high specific capacity. The study of conjugated carbonyl organic compounds is still in its infancy, such as the structure of carbonyl group. The relationship between crystal structure, derivatives and electrochemical properties is not clear. Therefore, the electrochemical performance of several terephthalates in sodium ion batteries is studied in this paper. The purpose of this paper is to summarize some internal relations between structure and performance. In this paper, the electrochemical activity of terephthalate system to sodium ion battery was systematically studied. Firstly, the neutralization reaction and precipitation reaction of acid and base were used to study the electrochemical activity of terephthalate system. Lithium terephthalate was prepared. PTALi2). Magnesium terephthalate (PTAMgN), calcium terephthalate (PTACaA), Barium terephthalate (Barium terephthalate) and aluminum terephthalate (PTAAl2 / 3). Then the electrochemical performance of terephthalate in sodium ion battery was studied. The results showed that the prepared terephthalate showed excellent performance of rate and good cycle stability for sodium ion battery. By comparing the electrochemical properties of PTALi2PTACa and PTAAl2/3, it was found that with the increase of metal cationic charge in terephthalate. Terephthalate showed excellent performance of rate and cycle. By comparing the electrochemical properties of PTAMgCa and PTABa, it was found that with the increase of metal cationic radius in terephthalate. Terephthalate showed excellent performance of rate and cycle. After it was known that terephthalate had electrochemical activity for sodium ion battery. The effect of crystalline water on the electrochemical properties of terephthalate was studied in this paper. Taking PTAMg as the research object, the PTA-Mg-2H2O containing crystalline water was prepared. The electrochemical properties of PTAMg 路2H2O and PTAMg were compared. The results showed that the electrochemical performance of PTAMg 路2H2O was better than that of PTAMg 路2H2O. Finally, the electrochemical performance of PTAMg 路2H2O was better than that of PTAMg 路2H2O. In view of the poor electrical conductivity of terephthalate, carbon coating technology was chosen to modify it. In this paper, PTAMg was selected as the research object and glycine as carbon source to implement carbon coating on PTAMg. The results show that the carbon coated PTAMg can increase the capacity of PTAMg to a certain extent, and the carbon coated PTAMg with a mass ratio of 15% carbon source has the best electrochemical performance.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912

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