氮掺杂中空介孔碳球的可控制备及性能研究

发布时间：2018-06-06 05:22

本文选题：中空碳球 + 淀粉　；参考：《天津工业大学》2017年硕士论文

【摘要】：超级电容器由于具有大的功率密度、长的循环稳定性、快的充放电能力等优点,作为储能装备有很大的市场潜力。而电极材料是决定超级电容器性能的重要因素之一,高度有序的介孔碳材料由于具有有序的中构造、高的比表面积、均匀和可调的孔结构、良好的导电性和优异的化学稳定性等特性,这些独特的化学和物理特性是其作为超级电容器最理想的电极材料。到目前为止,已经吸引了广大科研工作者巨大的兴趣和高度的重视。为了提高碳材料的电容性能,在其表面和结构框架中进行进一步的改性修饰是十分有必要的,本论文以制备超级电容器新型碳材料为目的,探索了一种新的、工艺简单的氮掺杂中空介孔碳球制备方法,并分别考察了该碳材料作为超级电容器的电极材料在碱性和中性电解质溶液中的电化学性能。本研究是以氨气为氮源,以淀粉为碳前驱体,经氯化钙溶液和碳酸钾/碳酸氢钾缓冲溶液预处理后,进行一步碳化和掺氮过程,得到氮掺杂中空介孔碳微球,并对合成中空碳微球的影响因素进行部分考察,主要包括碳化温度和预处理溶液的浓度等。通过扫描电镜、透射电镜、XRD、XPS、BET吸附测试,对电极活性碳材料的微观形貌、孔结构和表面官能团进行表征;通过循环伏安、恒流充放电和循环稳定性对超级电容器的电化学性能进行衡量,综合分析电极碳材料的微观形貌、孔结构和表面官能团的性质,以及电化学性能测试结果,探索其结构性质对超级电容器电化学性能的影响。实验结果表明,通过一步碳化和掺氮过程,能够制备出分散性较好、粒径分布相对均匀和形貌易控的氮掺杂中空碳微球,其比表面积高达750.6 m2g-1,以6MKOH溶液作为电解液,在扫速为5mVs-1比容量为240Fg-1,在300 mV s-1的高扫速下,其比容量达到163 Fg-1;容量保持率为67.9%;在1M Na2SO4中性电解质溶液中,扫速为5 mV s-1比容量高达155 Fg-1,在200 mV s-1的高扫速下,其比容量仍能达到69.6 Fg-1,其容量保持率为45%,在该中性电解质中的操作电位窗口扩展至2.0 V,拥有较大的能量密度。氢氧化钾溶液是一种腐蚀性液体,特别是在高浓度下,其腐蚀性更强,这限制了其在商业超级电容器中的应用,研究结果表明,该材料在中性Na2S04电解质溶液中具有相对较高的比容量和能量密度,降低了生产成本,有利于生态环境保护。
[Abstract]:Supercapacitors have great market potential as energy storage equipment due to their advantages of high power density, long cycle stability and fast charge-discharge capacity. The electrode material is one of the important factors that determine the performance of supercapacitor. The highly ordered mesoporous carbon material has ordered mesoporous structure, high specific surface area, uniform and adjustable pore structure. Excellent electrical conductivity and excellent chemical stability, these unique chemical and physical properties are the most ideal electrode materials for supercapacitors. Up to now, has attracted the vast number of scientific research workers huge interest and high attention. In order to improve the capacitive properties of carbon materials, it is necessary to modify them further in the surface and structural framework. In this paper, a new type of carbon materials for supercapacitors is proposed. The preparation method of nitrogen-doped hollow mesoporous carbon spheres was simple. The electrochemical properties of the carbon materials as electrode materials for supercapacitors in alkaline and neutral electrolyte solutions were investigated respectively. In this study, nitrogen doped hollow mesoporous carbon microspheres were prepared by one step carbonation and nitrogen doping with ammonia as nitrogen source and starch as carbon precursor after pretreatment with calcium chloride solution and potassium carbonate / potassium bicarbonate buffer solution. Some factors affecting the synthesis of hollow carbon microspheres were investigated, including carbonation temperature and concentration of pretreatment solution. The micromorphology, pore structure and surface functional groups of the electrode active carbon materials were characterized by scanning electron microscopy, transmission electron microscopy and XRDX XPS-BET adsorption test, and were characterized by cyclic voltammetry (CV), and cyclic voltammetry (CV). The electrochemical properties of supercapacitors were measured by constant current charge-discharge and cyclic stability. The microstructure, pore structure and surface functional group properties of electrode carbon materials were comprehensively analyzed, as well as the electrochemical performance test results. The effect of its structure and properties on the electrochemical performance of supercapacitors was investigated. The experimental results show that the nitrogen-doped hollow carbon microspheres with good dispersion, relatively uniform particle size distribution and easily controlled morphology can be prepared by one-step carbonization and nitrogen-doping process. The specific surface area of the hollow carbon microspheres is up to 750.6 m ~ (-2) g ~ (-1), and 6MKOH solution is used as electrolyte. When the specific capacity of 5mVs-1 is 240Fg-1, the specific capacity reaches 163Fg-1 at the high scanning speed of 300mV s-1, and the capacity retention is 67.9%. In the neutral electrolyte solution of 1M Na2SO4, the specific capacity of 5mV s-1 is up to 155Fg-1, and at 200mV s-1, the specific capacity is up to 155Fg-1. Its specific capacity can still reach 69.6 Fg-1, and its capacity retention rate is 45. The operating potential window in the neutral electrolyte extends to 2.0 V and has a large energy density. Potassium hydroxide solution is a corrosive liquid, especially at high concentration, which limits its application in commercial supercapacitors. The material has a relatively high specific capacity and energy density in neutral Na _ 2S _ 04 electrolyte solution, which reduces the production cost and is beneficial to the protection of ecological environment.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TM53

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