ACM基活化炭气凝胶的制备及其在双电层电容器中的应用

发布时间：2018-08-28 16:02

【摘要】：随着化石类能源的日益耗竭以及环境污染问题的日渐突显,绿色清洁能源受到社会越来越多的关注和重视,而作为新型储能元件的双电层电容器近年的发展尤其迅速。炭气凝胶是一类极具潜力和应用前景的双电层电容器用多孔炭电极材料。采用两亲性炭材料(ACM)制备炭气凝胶,具有原料成本低廉,过程简单易行、环境友好等优点,符合绿色化工的理念,具有一定的科研价值与应用前景。本文以混酸氧化中温煤沥青制备的两亲性炭材料(ACM)为原料,通过对ACM溶解过程和溶剂置换过程中溶剂的调控,制备出了不同形貌的有机气凝胶,并对凝胶的结构和形成机理作了初步分析。以丙酮置换法得到有机气凝胶OAs-1,经炭化稳定化后,分别采用KOH活化法和ZnCl2活化法调节孔道结构,制备活化炭气凝胶。系统研究了活化条件对活化炭气凝胶的形貌、收率、比表面积和孔道参数的影响,并考察了其作为双电层电容器电极材料的电化学行为。研究表明,采用KOH活化制备的活化炭气凝胶PCAs具有非常高的比表面积,活化收率为20%左右,低碱炭比活化时能够较好保持炭气凝胶的骨架结构。碱炭比为1.5时,PCAs-1.5比表面积高达2598.2 m2/g,小中孔主要分布在2~5 nm。在30%KOH为电解液的双电层电容器体系中,PCAs-1.5在0.05 A/g电流密度下的比容量高达283 F/g,40 A/g时的比容量仍然高达221.3 F/g,在5000次循环测试后的容量衰减仅为5.73%(电流密度为1 A/g条件下),表现出优异的倍率性能和循环性能。ZnCl2作为活化剂时,得到的ACAs样品较好的继承了炭气凝胶的三维骨架形貌,并且具有高于80%的活化收率。ZnCl2制备的多孔炭以微孔为主,中孔主要分布在2~3 nm。实验得到的最优活化条件为:活化温度是500℃、ZnCl2/CAs的质量比是3:1。在此条件下制备的ACAs-500-3-2样品比表面积为1306.8 m2/g。在水系电容器中,样品ACAs-500-3-2在电流密度为50 mA/g时的比容量高达255.2 F/g,40 A/g时比容量仍然有216.8 F/g,容量保持率为82.4%,体现出良好的大倍率性能。
[Abstract]:With the increasing depletion of fossil energy and environmental pollution, more and more attention has been paid to green and clean energy. As a new type of energy storage element, double-layer capacitor has been developed rapidly in recent years. Carbon aerogel is a kind of porous carbon used in double-layer capacitors with great potential and application prospects. Polar materials. Carbon aerogels prepared from amphiphilic carbon materials (ACM) have the advantages of low cost, simple process and friendly environment. It conforms to the concept of green chemical engineering and has certain scientific research value and application prospect. In this paper, amphiphilic carbon materials (ACM) prepared by mixed acid oxidation of medium temperature coal tar pitch are used as raw materials through the dissolution process of ACM. Organic aerogels with different morphologies were prepared by adjusting the solvents in the process of solvent replacement and acetone replacement. OAs-1 was obtained by acetone replacement. After carbonization and stabilization, the pore structure was adjusted by KOH activation method and ZnCl2 activation method, respectively, to prepare activated carbon aerogels. The effects of activation conditions on the morphology, yield, specific surface area and pore parameters of activated carbon aerogels were investigated, and the electrochemical behavior of activated carbon aerogels as electrode materials for double layer capacitors was investigated. The specific surface area of PCAs-1.5 is as high as 2598.2 m2/g when the ratio of alkali to carbon is 1.5, and the small and medium pores are mainly distributed between 2 and 5 nm. In the double-layer capacitor system with 30% KOH as electrolyte, the specific capacity of PCAs-1.5 is as high as 283 F/g at 0.05 A/g current density, 221.3 F/g at 40 A/g and 5000 times. When ZnCl2 was used as an activator, the ACAs samples inherited the three-dimensional skeleton morphology of the carbon aerogel and had a high activation yield of more than 80%. The porous carbon prepared by ZnCl2 was mainly microporous and mesoporous. The optimum activation conditions are as follows: activation temperature is 500 C and the mass ratio of ZnCl2 to CAs is 3:1. The specific surface area of ACAs-500-3-2 sample prepared under this condition is 1306.8 m2/g. The specific capacitance of ACAs-500-3-2 sample is as high as 255.2 F/g at current density of 50 mA/g and 2.2 F/g at 40 A/g. 16.8 F/g, the capacity retention rate is 82.4%, reflecting good high rate performance.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ427.26;TM53

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