功能化碳材料的制备及其在超级电容器中的应用

发布时间：2018-03-11 07:54

  本文选题：功能化碳材料　切入点：超级电容器　出处：《华中农业大学》2015年博士论文　论文类型：学位论文

【摘要】：超级电容器作为一种新型储能装置,集高能量密度、高功率密度、长使用寿命等特性于一身,是一种极具应用潜力的绿色能源,开展超级电容器的研究工作具有非常大的现实意义和社会效益。本论文主要研究了超级电容器的关键组成部分-电极材料。以碳材料为电极基体材料,选用不同的制备方法,改进其组成成分和微观结构,获得了多种类型的具有高电容量的功能化碳电极材料。采用各种表征手段对其形貌和结构进行表征,同时利用循环伏安、恒电流充放电、交流阻抗等方法测试材料相应的电化学性能。对相关的形成机理和结果进行了探讨分析,旨在得到具备优异电化学性能的碳电极材料。主要研究工作如下:1.以nano-Ca CO3为硬模板,三聚氰胺甲醛树脂(MF)为碳源和氮源,制备出新型氮掺杂多级孔碳材料。通过改变模板加入量和碳化温度,可以得到不同形貌和不同含氮量的多孔碳。含氮量高达20.9 wt%,具有丰富的孔洞结构和高的比表面积(834 m2 g-1)。电化学测试结果表明:900℃碳化条件下,模板比例高的样品具有最高的电容值283 F g-1(1 A g-1),此外,电极还展示了优异的倍率性能和长时间充放电循环稳定性。该方法简便,模板成本低,为合成多孔碳材料提供了新的思路。2、通过简单的水热法制备了石墨烯/Ni(OH)2复合电极材料,Ni(OH)2呈现出纳米线和纳米片两种形式,均匀的负载在石墨烯片上,包括α和β两种晶相。我们对其形成机理进行了详细的探讨和分析。与石墨烯和纯Ni(OH)2材料相比,复合材料具有更高的比电容值(970 F g-1),优良的倍率性能和较好的稳定性。其原因总结如下:Ni(OH)2具有优异的赝电容性质,与石墨烯复合后可以大大提高材料的整体电容值;石墨烯作为结构支撑材料,避免了Ni(OH)2在充放电过程中发生严重的聚集,增加电解液离子与活性位点的接触面积,提高材料的导电性;石墨烯的存在有效地改善了材料的倍率性能和稳定性。3、以Si O2球作为间隔物,离子液体(IL)作为结构导向剂,采用低温水热法合成了功能化的3D分级多孔石墨烯材料,该材料具有丰富的大孔和介孔,比表面积高达341 m2 g-1。Si O引入为材料提供了大量开放性的大孔,IL附着在石墨烯片上可以防止其在后处理过程中发生堆叠,并且改善石墨烯的导电性。这种独特的3D分级孔结构促进了电解液离子的扩散和电荷转移,继而提高了材料的利用效率。低温处理保留的大量含氧官能团,提高了材料的亲水性,而且在充放电过程中产生赝电容。实验结果表明,该材料具有高的比电容值,好的倍率性能和优异的循环稳定性。此外,组装的对称两电极电容器拥有13.3 k W kg-1的高功率密度,展现了非常大的应用潜力。同时,我们制备的功能化3D多孔石墨烯有望应用于其他领域,我们所用的制备方法能够对其他材料的设计调控起到借鉴和指导作用。
[Abstract]:As a new type of energy storage device, supercapacitor is a kind of green energy with high energy density, high power density and long service life. The research work of supercapacitor has great practical significance and social benefit. In this paper, the key component of supercapacitor, electrode material, is studied. Carbon material is used as electrode matrix material, and different preparation methods are selected. Various kinds of functional carbon electrode materials with high capacitance were obtained by improving their composition and microstructure. The morphology and structure were characterized by various means of characterization, at the same time, cyclic voltammetry, constant current charge and discharge were used. Electrochemical properties of the materials were measured by AC impedance method. The formation mechanism and results were discussed and analyzed to obtain carbon electrode materials with excellent electrochemical properties. The main research work is as follows: 1. Using nano-Ca CO3 as hard template, Melamine formaldehyde resin (MFF) was used as carbon source and nitrogen source to prepare a new type of nitrogen-doped multiporous carbon material. By changing the amount of template and carbonation temperature, Porous carbon with different morphology and nitrogen content can be obtained. The nitrogen content is up to 20.9 wts. it has abundant pore structure and high specific surface area of 834 m2 g-1.The electrochemical test results show that under the carbonation condition of 1: 900 鈩，

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