CuSe基纳米材料的制备及其电化学性能研究

发布时间：2018-01-01 17:32

本文关键词：CuSe基纳米材料的制备及其电化学性能研究　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：锂离子电池作为一种储能装置,由于具有比能量高、寿命长、环保轻便等特点已在手机等便携式设备中得到了广泛应用。但是,近年来由于电动汽车、电网储能等的高速发展,现阶段的锂离子电池技术已经满足不了这类设备的需求,因此开发出具有高容量、高功率、长寿命的锂离子电池负极材料是科学研究的热点。铜基硫属化合物中的铜离子具有较好的流动性,使其具有高的离子电导率和足够的空位供锂离子嵌入,是一种具有潜在应用价值的锂离子电池电极材料。因此,本课题选用Cu Se基材料作为研究对象,采用微波辅助法制备具有特殊形貌的CuxSe样品,并在此基础上采用溶剂热法合成Cu Se S三元纳米材料,然后通过X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱等对样品结构与形貌进行表征,测试其电化学性能,研究电化学性能与不同形貌、组成之间的关系。本课题采用微波辅助法在甲酰胺体系下合成了Cu2-xSe纳米棒,并研究了酒石酸钠和碱量对纳米棒尺寸和均一性的影响。由于其具有独特的一维纳米结构,能有效地提升其电化学性能,在50 m A g-1的电流密度下,经过100次充放电循环,容量仍能保持在210 m Ah g-1。采用微波法在乙二醇体系下合成了具有钉板状分级结构的Cu2-xSe纳米片。研究表明,体系中酒石酸钠的添加量增加会引起纳米片上生长的粒子数量增多。由于这种分级结构的存在,样品的电化学性能有所提升,首次放电容量为400m Ah g-1,循环30次之后容量仍为330 m Ah g-1。首次采用溶剂热法制备了Cu Se1-xSx三元材料,制备的样品具有六方相Cu Se结构,且选区电子衍射表明六方纳米片为单晶。研究发现,溶剂配比影响六方纳米片的厚度和尺寸,只有当乙二醇与水的比例为10:18时才能形成尺寸均一、厚度较薄的样品。Cu Se1-xSx六方纳米片的电化学性能测试表明,电极可逆容量可达500 m Ah g-1,循环60次之后容量稳定在300 m Ah g-1以上,而且在大电流密度下容量衰减并不明显。交流阻抗测试表明,随着循环次数的增加,电极的界面电荷转移电阻在降低。
[Abstract]:Lithium ion battery as an energy storage device, due to its high specific energy, long life, light environmental characteristics has been widely used in portable devices such as mobile phone. However, in recent years due to the rapid development of electric vehicles, power grid energy storage, the lithium ion battery technology has been unable to meet the the demand for equipment, thus developed has the advantages of high capacity, high power, long life lithium ion battery cathode material is a hot topic of scientific research. The copper based chalcogenide copper ionic compounds with good fluidity, which has high ionic conductivity rate and enough space for lithium ion insertion, is a kind of the potential application of the lithium ion battery electrode materials. Therefore, the project uses Cu Se based material as the research object, using microwave assisted preparation with special morphologies of CuxSe samples, and on the basis of the solvent thermal synthesis of Cu Se S three nano materials, and then by X ray diffraction, scanning electron microscopy, transmission electron microscopy, X ray photoelectron spectroscopy were used to characterize the structure and morphology of the samples, test their electrochemical performances and electrochemical properties of different morphology, the relationship between composition. The subject of Cu2-xSe nanorods were synthesized in the system using formamide microwave assisted method, and studied the effect of tartaric acid sodium and alkali on the size and uniformity of the nanorods. Because of its unique one-dimensional nanostructures, can effectively improve the electrochemical performance, in the current density of 50 m A g-1, after 100 cycles, the capacity can still remain in the glycol system the synthesis of nano Cu2-xSe with nail plate hierarchical structure at 210 m Ah g-1. by microwave method. The research results show that the addition of sodium tartrate system increase will cause the growth of the number of particles on the nano film The amount of increase. Because of the hierarchical structure, the electrochemical properties of samples increase, the first discharge capacity was 400m Ah g-1, after 30 cycles the capacity is still 330 m Ah g-1. for the first time by solvothermal method Cu Se1-xSx three materials were prepared, prepared samples with six Cu Se structure, and electron the six diffraction show that the nano film is single crystal. The study found that the solvent ratio influence the thickness and size of six square nanoplates, only when ethylene glycol and water ratio of 10:18 to the formation of uniform size, thickness of thin samples of.Cu Se1-xSx six nano plate electrochemical performance test shows that the electrode reversible capacity can reach 500 m Ah g-1, after 60 cycles the capacity of M Ah stabilized at more than 300 g-1, and in the case of high current density attenuation capacity is not obvious. The EIS test shows that with the increase of cycle number, charge transfer resistance at the electrode interface Lower.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O646.54;TM912

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