多孔管状碳材料的制备及其电容性能的研究

发布时间：2018-03-01 16:53

  本文关键词： 双电层电容器 活性炭 碳纳米管 活化剂　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：双电层电容器因其具有高功率密度、快的充放电速率、长循环寿命等特点,受到许多人的关注。在电极/电解质界面,双电层电容器物理存储能量是基于电化学双电层机制。因此,高比表面积和短离子传输路径是碳基电极材料的基本要求。多孔管状碳材料同时具备1D纳米结构和多孔结构的优点,不仅可以提供高比表面积,还可以提供快速离子通路和高电解质-电极接触面积,使得电解质离子的传输更快和电极的利用率更高。本文中以FeCl_3为催化剂,三聚氰胺为碳源,通过热解制备不同微观结构的N掺杂碳纳米管(CNTs)。通过三聚氰胺和FeCl_3的摩尔比和煅烧温度来调控N掺杂CNTs的微观结构。当三聚氰胺和FeCl_3的摩尔比为4,碳化温度为700℃时,形成具有竹节状结构的CNTs。样品的BET表面积和电容随着三聚氰胺和FeCl_3的摩尔比的增加而增加,并且最大BET表面积和电容分别为294 m~2/g和67 F/g。但是,低电容对于双电层电容器的电极材料是不够的。为了进一步提高CNTs的电容性能,我们引入造孔剂ZnCl_2,来增加CNTs的比表面积。通过一步法合成高气孔率的N掺杂CNTs/Fe_3C。原位形成的Fe_3C纳米棒嵌入到CNTs的内部结构。孔结构分析表明,N掺杂的CNTs/Fe_3C拥有大的比表面积高达1206.23 m~2/g。在电流密度为0.1 A/g时,N掺杂的CNTs/Fe_3C电极显示出181 F/g的高比电容,以及优异的电容率和循环稳定性。为了降低制备成本,利用废弃的生物质原料竹筷子作为碳源。通过水热法除去竹筷子中的木质素,来获得纤维素纤维,然后用KOH作为活化剂来制备多孔碳微管/薄片复合材料。所制备的样品具有高达2337 m~2/g的比表面积。在6M KOH溶液中,当电流密度0.1 A/g时,表现出212 F/g的高比电容。在电流密度为1 A/g时,经过1000次循环后电容保持率为96%。结果表明,竹筷子可以作为储能装置的原材料。
[Abstract]:Because of its high power density, fast charge and discharge rate and long cycle life, double layer capacitors have attracted much attention. The physical storage of energy in double layer capacitors is based on the electrochemical double layer mechanism. High specific surface area and short ion transport path are the basic requirements of carbon based electrode materials. Porous tubular carbon materials have the advantages of both 1D nanostructure and porous structure, which can not only provide high specific surface area. It can also provide fast ion path and high electrolyte-electrode contact area, which can make electrolyte ion transport faster and electrode utilization higher. In this paper, FeCl_3 is used as catalyst, melamine as carbon source, melamine as carbon source, melamine as carbon source, and melamine as carbon source. N-doped carbon nanotubes with different microstructure were prepared by pyrolysis. The microstructure of N-doped CNTs was controlled by the molar ratio of melamine and FeCl_3 and the calcination temperature. When the molar ratio of melamine to FeCl_3 was 4, the carbonization temperature was 700 鈩，

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