基于铁氧体锂离子电池负极材料的构筑及其性能研究

发布时间：2018-04-13 16:49

本文选题：锂离子电池 + 负极材料　；参考：《南京理工大学》2017年硕士论文

【摘要】：近年来,随着新能源产业的快速发展,越来越多高性能的电极材料被应用于储能器件中。单一组分的铁氧体电极材料由于自身固有的缺陷,很难满足现今动力电池高能量密度、高功率密度和循环稳定性强的要求。开发研究新型复合电极材料日渐成为电池研发的重点,利用多组分材料之间的协同效应,发挥各个组份材料的优势,将其应用于锂离子电池电极材料有利于整体性能的提升与优化。在本论文研究中,设计制备了一系列基于铁氧体的纳米复合材料,并将其应用于锂离子电池负极材料,研究其电化学储锂性能以及储锂机理。1.铁氧体-氮掺杂石墨烯纳米复合材料的制备及储锂性能研究通过一步水热反应,制备氮掺杂石墨烯并将铁氧体(MFe204,M=Ni,Co,Zn)纳米颗粒均匀负载在其表面,得到铁氧体-氮掺杂石墨烯纳米复合材料,并将其应用于锂离子电池负极材料。利用氮原子掺杂有效调变石墨烯表面的电子层结构,提供更多的储锂活性位点,同时发挥铁氧体高的储锂容量,实现性能优异、循环稳定的锂离子电池负极材料的可控制备。并通过XRD、Raman、TEM、BET等手段进行结构和形貌表征,以及进行电化学性能测试。结果表明,所制备的铁氧体-氮掺杂石墨烯纳米复合材料表现出良好的循环性能和倍率性能。2.铁氧体-有序插层石墨烯纳米复合材料的制备及储锂性能研究通过两步法制备出铁氧体-有序插层石墨烯纳米复合材料,并研究其电化学储锂性能。有序插层石墨烯巨大的比表面积使得铁氧体纳米粒子能够均匀分散,有效缓解在锂离子嵌入与脱出过程中体积收缩与膨胀,有利于电化学储锂的循环稳定性。有机插层石墨烯的有序排列以及优异的导电性,减小了电荷及锂离子在电极材料的中的扩散阻力,从而有利于大电流密度的充放电性能。多组分材料之间的协同效应,使得所制备的纳米复合材料具有卓越的电化学储锂性能。3.铁酸镍纳米棒-石墨烯纳米复合材料的制备及储锂性能研究利用金属有机框架设计、制备铁酸镍纳米棒的前驱体,在不同气氛下的焙烧,将所得产物应用于锂离子电池负极材料并测试其性能。实验表明,在氮气氛围中焙烧得到的产物具有良好的循环稳定性和倍率性能,而在氧气中焙烧则性能较差,这主要是因为在但其氛围中能够保留碳骨架,不仅可以增强材料的导电性,有利于电荷转移,同时也可以防止纳米粒子在充放电过程中粉化破裂,改善材料的的循环稳定性。与石墨烯材料复合,凭借石墨烯优异的电化学性质、良好的导电性和机械强度以及巨大的比表面积,复合材料的储锂性能得到进一步优化与改善。
[Abstract]:In recent years, with the rapid development of new energy industry, more and more high-performance electrode materials have been used in energy storage devices.Because of its inherent defects, the single component ferrite electrode material can not meet the requirements of high energy density, high power density and high cycle stability of power battery.The development and research of new composite electrode materials have become the focus of battery research and development. The advantages of each component material can be brought into play by the synergistic effect among multicomponent materials.Its application in the electrode material of lithium ion battery is beneficial to the improvement and optimization of the overall performance.In this thesis, a series of ferrite based nanocomposites were designed and fabricated, and applied to the cathode materials of lithium ion batteries. The electrochemical lithium storage performance and the mechanism of lithium storage were studied.Preparation and Lithium Storage Properties of Nitrogen-doped Graphite Nanocomposites; Nitrogen-doped graphene was prepared by one step hydrothermal reaction and loaded on the surface of ferrite MFe204 (MFe204) NiCoCoZN) nanoparticles.Ferrite-nitrogen-doped graphene nanocomposites were prepared and used as anode materials for lithium ion batteries.The electronic layer structure of graphene surface can be effectively adjusted by nitrogen atom doping to provide more lithium-storage active sites. At the same time, the high lithium-storage capacity of ferrite can be used to achieve the controllable preparation of cathode materials for lithium ion batteries with excellent performance and stable cycle.The structure and morphology were characterized by means of XRDX Ramante Tem BET, and the electrochemical properties were tested.The results show that the ferrite nitrogen-doped graphene nanocomposites exhibit good cycling and rate properties.Preparation and lithium storage properties of ferrite-ordered intercalated graphene nanocomposites the ferrite-ordered intercalated graphene nanocomposites were prepared by two-step method and their electrochemical lithium storage properties were studied.The large specific surface area of ordered intercalated graphene enables the homogeneous dispersion of ferrite nanoparticles, which effectively alleviates the volume contraction and expansion during the intercalation and removal of lithium ions, which is conducive to the cyclic stability of electrochemical lithium storage.The ordered arrangement and excellent electrical conductivity of organic intercalated graphene reduce the diffusion resistance of charge and lithium ions in electrode materials, which is beneficial to the charge-discharge performance of high current density.Because of the synergistic effect among multicomponent materials, the nanocomposites have excellent electrochemical lithium storage properties.Preparation and lithium storage properties of nickel ferrate nanorod-graphene nanocomposites; preparation of nickel ferrate nanorods precursor by metal-organic frame design and calcination in different atmosphere.The product was applied to the cathode material of lithium ion battery and its performance was tested.The experimental results show that the products calcined in nitrogen atmosphere have good cycling stability and rate performance, while those calcined in oxygen have poor performance, which is mainly due to the ability to retain the carbon skeleton in the atmosphere.It can not only enhance the conductivity of the material, but also prevent the particles from breaking down during charge and discharge, and improve the cycle stability of the material.With the excellent electrochemical properties of graphene, good electrical conductivity and mechanical strength and huge specific surface area, the lithium storage properties of the composites were further optimized and improved.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912

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