静电纺丝法构筑一维纳米杂化材料及其电化学性能研究

发布时间：2018-03-12 21:49

本文选题：静电纺丝　切入点：磷化钴　出处：《东华大学》2017年硕士论文　论文类型：学位论文

【摘要】：伴随着人类文明的发展,突显出许多亟待解决的问题,诸如环境污染和能源危机。面对以上问题,必须发展先进的能源技术,实现能源的绿色化。在能源转化和储能系统研究领域,普遍持有的共识是一维纳米材料(包括纳米线、纳米棒和纳米管等)因具备较高的比表面积、大孔隙率和极大的长径比而被认为是最为理想的材料之一。静电纺丝技术自1934年被首次发现后,就引起了人们的广泛关注和深入研究。目前,静电纺丝作为有效的可以大规模连续化制备纳米纤维的方法之一被应用到各个研究领域。与其他制备一维纳米材料的方法相比,该方法具有操作设备简单、纺丝成本低廉、可纺纤维种类繁多和纤维形貌可控等优势。通过这种方法制备的一维纳米材料具有大比表面积、高孔隙率、大长径比等优势。通过加入功能性组分来有机的结合一维纳米材料与功能性组分的优势,制备获得一维纳米杂化材料在众多领域中具有广阔的应用前景。本文采用静电纺丝技术制备一维纳米杂化材料,通过无机组分的加入使其具备独特的功能性,经过预氧化、高温碳化、中温磷化和聚合物包覆、碳化等处理过程,成功制备功能化的一维纳米杂化材料,并探究其在电化学催化析氢催化剂和锂离子电池负极材料中的应用。本论文研究分为两个部分。其一,将四水合乙酸钴(Co(Ac)2·4H2O)和聚乙烯吡咯烷酮(PVP)共混,采用静电纺丝法制备一维纳米杂化材料Co@PVP,再经过200°C的预氧化,在空气中煅烧到550°C、2 h后得到一维中空纳米杂化材料四氧化三钴(Co3O4),再将得到的四氧化三钴与次亚磷酸钠(NaH2PO2)以一定的比例混合,在惰性气体保护下300°C中温磷化2 h,即成功制备得到一维中空纳米材料Co P,该一维纳米材料作为析氢催化剂时,在10 mA cm-2的电流密度下,只有-152 mV的过电位,说明其催化效率高,能量转化效果好。循环10 h后催化活性几乎没有衰减,说明材料的催化稳定性好。其二,将纳米硅(Si)颗粒与聚甲基丙烯酸甲酯(PMMA)、聚乙烯吡咯烷酮(PVP)混合。静电纺丝过程的独特之处在于将铝箔改用水接收,然后置于0~3°C的水溶液中聚合吡咯,之后在惰性气体下850°C,高温碳化2 h。最终成功制备得到具有多级孔结构的一维纳米杂化纤维材料Si@NC。将其组装成半电池测试电化学性能,在100圈的充放电循环以及倍率性能测试中,当电流密度由2 A g-1变为最初的0.1 A g-1时,其比容量高达910 mA h g-1,为同电流密度下电池初始比容量的100%,说明材料具有优异的倍率性能;而在1 A g-1的电流密度下循环测试200圈后,其放电比容量仍有515 mA h g-1,占1 A g-1电流密度下首次放电比容量(697 mA h g-1)的74%,说明该Si@NC具有优异的循环性能,有望作为一个理想的锂离子电池负极材料得到应用。
[Abstract]:With the development of human civilization, many problems need to be solved, such as environmental pollution and energy crisis. Achieving green energy. In the field of energy conversion and energy storage systems, there is a general consensus that one-dimensional nanomaterials (including nanowires, nanorods, nanotubes, etc.) have high specific surface areas, Macroporosity and great aspect ratio are considered as one of the most ideal materials. Electrostatic spinning technology has been widely concerned and deeply studied since it was first discovered in 1934. Electrospinning is one of the effective methods to fabricate nanofibers on a large scale and has been applied to various research fields. Compared with other methods for preparing one-dimensional nano-materials, this method has the advantages of simple operation equipment and low spinning cost. There are many kinds of textile fibers and the morphology of the fibers is controllable. The one-dimensional nanomaterials prepared by this method have large specific surface area and high porosity. Advantages such as large aspect ratio. Organic combination of one-dimensional nanomaterials with functional components by adding functional components, The preparation of one-dimensional nano-hybrid materials has a broad application prospect in many fields. In this paper, one-dimensional nano-hybrid materials are prepared by electrostatic spinning technology. The one-dimensional nano-hybrid materials have unique functions and are preoxidized by the addition of inorganic components. The functionalized one-dimensional nano-hybrid materials were successfully prepared by high-temperature carbonization, medium-temperature phosphating and polymer coating, carbonization and so on. Its application in electrochemical catalytic hydrogen evolution catalyst and anode materials for lithium ion batteries was investigated. The study was divided into two parts. First, the blends of cobalt acetate tetrahydrate (CoAcN) 2 路4H 2O and polyvinylpyrrolidone (PVP) were prepared. The one-dimensional nano-hybrid Costep PVP was prepared by electrospinning method and then preoxidized at 200 掳C. After calcined in the air for 2 h, the one-dimensional hollow nano-hybrid material cobalt trioxide (Co _ 3O _ 4O _ 4) was prepared, and then mixed with NaH _ 2PO _ 2 (NaH _ 2PO _ 2) in a certain proportion. The one-dimensional hollow nano-material Co P was successfully prepared under the protection of inert gas at 300 掳C for 2 h at medium temperature. When the one-dimensional nanomaterials were used as catalysts for hydrogen evolution, there was only -152mV overpotential at the current density of 10mA cm-2, which indicated that the catalytic efficiency was high. The effect of energy conversion is good. After 10 hours of cycle, the catalytic activity has almost no decay, which indicates that the catalytic stability of the material is good. The nano-SiSi particles were mixed with polymethyl methacrylate (PMMA) and polyvinylpyrrolidone (PVP). The unique feature of the electrostatic spinning process was that the aluminum foil was replaced with water and then placed in a water solution of 0 ~ 3 掳C to polymerize pyrrole. After carbonation at high temperature for 2 h at 850 掳C in the inert gas, the one-dimensional nano-hybrid fiber material Siforeign NCwith multilevel pore structure was successfully prepared. It was assembled into a semi-battery to test the electrochemical performance, and the electrochemical performance was tested in 100 cycles of charge and discharge cycles and rate performance tests. When the current density changed from 2 A g -1 to the initial 0.1 A g -1, the specific capacity of the cell reached 910 Ma h g -1, which was 100% of the initial specific capacity of the battery at the same current density, indicating that the material had excellent rate performance. The specific discharge capacity of the Si@NC is still 515mAhg-1 at current density of 1 A g ~ (-1), accounting for 697 Ma 路g ~ (-1) of the initial discharge capacity at 1 A g ~ (-1), which indicates that the Si@NC has excellent cycling performance. It is expected to be an ideal anode material for lithium ion batteries.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM912

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