多维碳材料的构建及其电化学性能的研究

发布时间：2018-06-05 05:47

本文选题：石墨烯 + 富勒烯　；参考：《天津大学》2014年硕士论文

【摘要】：超级电容器具有容量大、功率密度高、循环寿命长等特点，在各种领域有着广泛的应用。其研究重点是提高能量密度和功率密度，发展具有高比表面积、电导率和结构稳定性的电极材料。石墨烯是碳原子紧密堆积而成的蜂窝状二维晶格碳纳米材料，具有良好的电学、力学和热学性质，是极具潜力的储能材料。但是单一组分的石墨烯无法满足电化学检测的所有要求，且石墨烯本身的卷曲、团聚、层间的堆叠和其在溶剂中的分散性等限制了它在电化学领域中的应用。因此，对石墨烯进行掺杂或与其他材料形成复合电极材料是当前研究的一个热点。本文的研究目标是将多种形态碳插层到石墨烯中，重点是构建多维的石墨烯纳米复合材料，发挥它们之间的相互协同作用，，改善石墨烯容易发生团聚的性质，提高其电化学性能。以氧化石墨和常见的糖为原料，通过超声-煅烧法制备石墨烯/碳纳米复合材料。研究表明，煅烧温度、糖类的用量和种类对产物的形貌、结构有重要影响，进而影响产物的电化学性能。当以葡萄糖为碳源时，制备的石墨烯/碳纳米复合材料的比表面积为414.8m2·g-1。该材料用作超级电容器的电极材料时，在0.5A·g-1电流密度下比电容的值为273F g-1。在1A·g-1的电流密度下循环2000次后，其放电容量仍保持237F·g-1，循环稳定性好，并且具有较好的大电流放电能力。以氧化石墨和处理的富勒烯为原料，在不同的条件下还原，通过加热回流法制备石墨烯/富勒烯纳米复合材料。研究表明，以葡萄糖做还原剂时有利于复合材料的形成。该材料用作超级电容器的电极材料时，在1A·g-1的电流密度下循环1000次后其放电容量仍保持135.36F·g-1。以氧化石墨和单壁碳纳米管为原料，通过在水溶剂中加热回流处理，在氮气的保护下，高温煅烧法制备石墨烯/单壁碳纳米管复合纳米材料。结构测试表明单壁碳纳米管分散到石墨烯的表面，接触良好。该材料用作超级电容器的电极材料时，在1A·g-1的电流密度下，比电容达到163.8F·g-1。经过1500次充/放电循环后电容为初始值的90.56％，表明这种材料具有很好的稳定性。
[Abstract]:Supercapacitors with large capacity, high power density and long cycle life are widely used in various fields. The research focus is to improve the energy density and power density, and to develop electrode materials with high specific surface area, conductivity and structural stability. Graphene is a honeycomb two-dimensional lattice carbon nanomaterials, which has good electrical, mechanical and thermal properties, and is a potential energy storage material. However, the single component graphene can not meet all the requirements of electrochemical detection, and the crimp, agglomeration, interlaminar stacking and dispersion of graphene in the solvent restrict its application in the electrochemical field. Therefore, doping graphene or forming composite electrode materials with other materials is a hot topic. The aim of this paper is to intercalate various forms of carbon into graphene, with emphasis on the construction of multi-dimensional graphene nanocomposites, so as to improve the agglomeration properties of graphene. The electrochemical performance was improved. Graphene / carbon nanocomposites were prepared by ultrasonic-calcination method using graphite oxide and common sugar as raw materials. The results show that the calcination temperature, the amount and type of carbohydrates have an important effect on the morphology and structure of the products, and then affect the electrochemical properties of the products. When glucose was used as carbon source, the specific surface area of graphene / carbon nanocomposites was 414.8m2 g-1. When the material is used as electrode material for supercapacitor, the specific capacitance is 273F g-1 at the current density of 0.5A g ~ (-1). After 2000 cycles at the current density of 1A g ~ (-1), the discharge capacity is still 237F g ~ (-1), the cycle stability is good, and the discharge capacity is high. Graphene / fullerene nanocomposites were prepared by heating reflux method with graphite oxide and treated fullerenes as raw materials and reduced under different conditions. The results show that glucose as reducing agent is beneficial to the formation of composite materials. When the material is used as electrode material of supercapacitor, its discharge capacity remains 135.36F g-1 after 1000 cycles at the current density of 1A g ~ (-1). Graphene / single-walled carbon nanotubes (SCNTs) were prepared by high temperature calcination with graphite oxide and single-walled carbon nanotubes as raw materials by heating and refluxing in water solvent and under the protection of nitrogen. The structure test showed that the single walled carbon nanotubes dispersed onto the surface of graphene and had good contact. When the material is used as electrode material of supercapacitor, the specific capacitance reaches 163.8F g-1 at the current density of 1A g ~ (-1). After 1500 charge / discharge cycles, the capacitance is 90.56 with initial value, which shows that the material has good stability.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O613.71;TM53

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