石墨烯基锂离子电池复合电极材料的设计合成和电化学性能研究

发布时间：2018-02-28 02:46

本文关键词： 锂离子电池负极材料正极材料石墨烯氧化锌五氧化二钒　出处：《北京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：可充电式锂离子电池具有能量密度高，维修费用低和自放电能力低等特点，在学术和商业领域吸引了极大的注意，使其成为了便携式电子设备、电动汽车和混合电动汽车的潜在电源。锂离子电池正负极电极材料是锂离子电池的重要组成部分，因其对锂离子电池的电化学性能有关键作用，所以电极材料的选择是锂离子电池性能得到提升的关键因素之一。石墨烯（Graphene）是由单层sp2杂化碳原子组成的六方蜂巢状二维结构物质，自2004年首次报道独立存在以来，在力学、热学、电学、光学等方面的优异性能，使之成为近年来化学、材料科学及物理学领域的研究热点。近来，石墨烯在作为锂离子电池的电极材料方面也激发了极大地研究兴趣，以石墨烯、不同含氧官能团的石墨烯衍生物如氧化石墨和还原氧化石墨等作为不同金属和金属氧化物纳米结构物质生长的2D基底，并以此作为电极材料的大量工作已被开展，且取得了一定的进展。本文以石墨烯基化合物为研究对象制备出了系列复合材料，采用XRD、XPS、SEM、TEM等测试方法对这些材料进行物相组成和结构形貌的表征，，并且将其作为正负极电极材料组装成锂离子电池，测试了其电化学性能。主要的研究内容如下： (1)采用冷冻干燥-热还原方法合成了氮（N）掺杂的ZnO-Graphene复合纳米材料。以氢氧化锌[Zn(OH)2]、乙二胺（EDA）和氧化石墨烯为原料，用冷冻干燥-热还原方法制备了N掺杂的ZnO-Graphene复合纳米材料。制备过程简单，条件易控制，无需任何模板和表面活性剂。该材料作为锂离子电池负极材料，容量高、循环稳定、倍率性能好，且与纯相ZnO、纯相Graphene及未掺N的ZnO-Graphene相比电池性能有了很大的提高，在100mA g-1电流密度下，容量可以达到900mAh g-1。 (2)采用水热-热解方法合成了V2O5-Graphene复合纳米材料。以偏钒酸铵（NH4VO3）和氧化石墨烯为原料，用水热-热解的方法合成了V2O5-Graphene复合纳米材料。方法简单，易操作，成本低等。合成的材料结构稳定，将其作为锂离子电池正极材料，电化学性能较好。在100mA g-1电流密度下，容量可以达到325mAh g-1。
[Abstract]:The rechargeable lithium-ion battery, with its high energy density, low maintenance cost and low self-discharge capacity, has attracted great attention in the academic and commercial fields, making it a portable electronic device. Potential power supply for electric vehicles and hybrid electric vehicles. Cathode materials for lithium-ion batteries are an important component of lithium ion batteries because they play a key role in the electrochemical performance of lithium ion batteries. Therefore, the selection of electrode materials is one of the key factors to improve the performance of lithium-ion batteries. Graphene (Graphene) is a hexagonal honeycomb structure material composed of monolayer sp2 hybrid carbon atoms. Because of its excellent thermal, electrical and optical properties, graphene has become a hot topic in recent years in the fields of chemistry, material science and physics. Recently, graphene has also aroused great interest in the field of electrode materials for lithium ion batteries. Using graphene, graphene derivatives with different oxygen functional groups, such as graphite oxide and reduced graphite oxide, as 2D substrates for the growth of different metal and metal oxide nanostructures, a great deal of work has been carried out as electrode materials. Some progress has been made. In this paper, a series of composite materials were prepared from graphene based compounds. The phase composition and structure morphology of these materials were characterized by XRDX XPS SEMTEM, and the materials were used as cathode electrode materials to form lithium ion batteries. The electrochemical properties have been tested. The main contents of the study are as follows:. 1) ZnO-Graphene nanocomposites doped with nitrogen nitride were synthesized by freeze-drying and thermal reduction method. Using zinc hydroxide [Zn(OH)2], ethylenediamine (EDA) and graphene oxide as raw materials, N-doped ZnO-Graphene composite nanomaterials were prepared by freeze-drying and thermal reduction method. No templates and surfactants are needed. The material is of high capacity, stable cycling, good performance of rate and high performance compared with pure phase ZnO, pure phase Graphene and ZnO-Graphene without N, which is a kind of anode material for lithium ion battery with high capacity, stable cycle and good rate of performance, and the performance of the battery is greatly improved compared with pure phase ZnO, pure phase Graphene and non-doped ZnO-Graphene. Under the current density of 100mAg-1, the capacity can reach 900mAh g-1. The V _ 2O _ 5-Graphene composite nanomaterials were synthesized by hydrothermal-pyrolysis method. Using ammonium metavanadate (NH4VO3) and graphene oxide as raw materials, V _ 2O _ 5-Graphene composite nanomaterials were synthesized by hydrothermal pyrolysis. The method is simple, easy to operate and low in cost. The synthesized materials have stable structure and are used as cathode materials for lithium ion batteries. The electrochemical performance is good. At the current density of 100mA g ~ (-1), the capacity can reach 325 mAh g ~ (-1).
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TM912

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