基于石墨烯纸的超级电容储能特性研究

发布时间：2018-01-01 22:19

本文关键词：基于石墨烯纸的超级电容储能特性研究　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：超级电容器是一种新型的电化学储能元件,拥有着比锂离子电池更高的功率密度和循环寿命,而被广泛研究。石墨烯纸具有良好的自支撑能力及导电性,在作为超级电容器电极材料时,不再需要粘结剂和导电剂的加入,正成为当今的超级电容器电极材料的研究热点。本文首先采用化学还原法制备了石墨烯,并利用真空抽滤法得到石墨烯纸,然后对其进行超级电容储能性能测试分析,发现在较低的扫速下,该种石墨烯纸表现出了良好的电容性能。在水系电解液中测得10mVs-1时的比电容达到了150Fg1。但是,随着扫速的增大,表现出了明显的电容衰减,在1000mV S-1时,比电容只有71.5F g-1。这说明真空抽滤得到的石墨烯纸内部石墨烯片的紧密堆叠,降低了石墨烯纸的比表面积利用率,而影响了其电容性能。针对化学还原石墨烯纸堆叠紧密的不足,提出了以常压直流辉光放电扫描正柱区等离子体还原得到石墨烯纸(P-rGO)的方法。经材料表征发现,P-rGO具有良好的孔隙结构,拥有大量的开放性通道,且具有优异的流体渗流性能。相比于传统化学法制备的石墨烯纸(C-rGO),拥有着更大的比电容,在有机体系测试得到,10mV s-1时P-rGO的比电容为181.4F g1,而传统方法制备的石墨烯纸只有为120F g-1。P-rGO还表现出了更好的倍率性能。当电流密度从1A-1增加到50A g-1时,P-rGO的比电容从162F g-1只降到125F g-1,比电容的保持率为77%,而传统方法制备的石墨烯纸的比电容保持率只有18%,要远远小于P-rGO。为了获得高倍率性能的石墨烯纸超级电容器,利用垂直石墨烯的高导电率及多暴露边缘等特点,对集流体与活性材料之间进行桥接,可为集流体和活性材料界面之间提供大量的接触点,从而减少了该界面间的电荷传输路径,减小了界面的接触电阻。结果显示,通过垂直石墨烯桥接集流体与活性材料的石墨烯纸超级电容器拥有良好的倍率性能,当扫速从20mV s-1增加到1000mV s-1,依然能够保持约90%的比电容。且当电流密度达到600A g-1时,可以获得超高的功率密度为112.6kW kg-1,同时仍能保持130F g-1的高比电容值。
[Abstract]:Supercapacitor is a new type of electrochemical energy storage element, which has higher power density and cycle life than Li-ion battery, and has been widely studied. Graphene paper has good self-supporting ability and electrical conductivity. As electrode materials of supercapacitors, the binder and conductive agent are no longer needed, which is becoming the research hotspot of electrode materials for supercapacitors. In this paper, graphene was prepared by chemical reduction method, and the graphene paper was obtained by vacuum filtration. Then the energy storage performance of super capacitor was tested and analyzed, and it was found that at low sweep speed. This kind of graphene paper shows good capacitance performance. The specific capacitance of 10mVs-1 measured in aqueous electrolyte reaches 150Fg1.However, with the increase of sweep speed. At 1000mV S-1, the specific capacitance is only 71.5 F g -1, which indicates the compact stacking of graphene sheets inside graphene paper by vacuum filtration. The specific surface area utilization ratio of graphene paper is reduced, and its capacitance performance is affected. In order to overcome the shortage of chemical reduction graphene paper stack, a method of plasma reduction of graphene paper by normal pressure DC glow discharge scanning positive column plasma reduction was proposed, which was characterized by material. P-rGO has a good pore structure, a large number of open channels, and excellent fluid percolation performance, compared with the traditional chemical method of graphene paper preparation C-rGO. With larger specific capacitance, the specific capacitance of P-rGO was 181.4 F / g1 when the organic system was tested with 10mV s ~ (-1). However, the graphene paper prepared by the traditional method showed better performance when the current density was increased from 1A ~ (-1) to 50 A ~ (-1) g ~ (-1). The specific capacitance of P-rGO was only reduced from 162 F g -1 to 125 F g -1, and the specific capacitance retention rate was 77%, while the specific capacitance retention rate of conventional graphene paper was only 18%. It is much smaller than P-rGO. In order to obtain graphene paper supercapacitors with high rate performance, the high conductivity and multiple exposed edges of vertical graphene were used to bridge the current collection with active materials. It can provide a large number of contact points between the interface of the collector and the active material, thus reducing the charge transfer path between the interface and the contact resistance of the interface. The graphene paper supercapacitors connected with active materials by vertical graphene bridging have good rate performance, when the sweep speed is increased from 20mV s-1 to 1000mV s-1. When the current density reaches 600A g ~ (-1), a high power density of 112.6kW kg-1 can be obtained. At the same time, the high specific capacitance of 130 F g -1 can be maintained.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM53

【参考文献】