3D石墨烯基复合电极柔性超级电容器的设计、制备和组装

发布时间：2018-01-14 03:08

本文关键词：3D石墨烯基复合电极柔性超级电容器的设计、制备和组装　出处：《兰州大学》2014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的电能存储器件,由于相比于传统的平行板电容器具有更高的能量密度,而相比于锂离子电池具有更高的功率密度和更长的寿命,而被广泛的研究。随着柔性电子学的发展,柔性超级电容器在柔性显示器件、柔性储能系统等方面具有很大的应用潜能。因此,轻质的柔性高性能储能系统越来越受到人们的重视。而石墨烯基柔性超级电容器由于其优异的特性成为很有潜力的发展方向。本论文中,以压薄的泡沫镍为模板和催化基底,以CH4为碳源,利用化学气相沉积(CVD)技术在1000℃的生长温度下生长了石墨烯。用HCl腐蚀去掉泡沫镍后,获得自支撑的柔性3D石墨烯(3DG)。所制备的超薄(200μm)3DG具有低的密度(0.70-0.75mg/cm2).高的电导率(55S/cm)、大的比表面积(392m2/g)和优异的柔韧性等优点。随后我们利用电沉积法在其上沉积MnO2制备了柔性的3DG/MnO2复合电极。由于3DG具有大的比表面积,它成为负载MnO2的优良基底,从而保证了高达9.8mg/cm2的MnO2负载量(对应于～92.9%的全电极比重),在2mV/s的扫描速率下获得了1.42F/cm2的最高面积比容量。从实际应用的角度考虑,优化了MnO2在全电极中的比重并获得了130F/g的全电极比容量。另外,我们将3DG/MnO2复合电极夹于聚合物隔膜两侧,形成三明治结构并在外边用PET塑料进行包装,组装了质量轻于10mg、厚度～0.8mm的柔性对称超级电容器。本研究为实现柔性、轻质、低成本和环境友好型的能量存储系统提供了参考。为了开发具有高功率密度的柔性超级电容器,我们通过在3DG上生长碳纳米管(CNTs)网络,制备了自支撑的柔性3DG/CNTs/MnO2复合电极。由于其中引入了相互交联的CNTs网络,所以形成了不间断连接的三元3D结构,从而在复合电极中构建了快速的电子和电解液离子扩散通道。因此,所制备的3DG/CNTs/MnO2复合电极在比容量和速率特性方面都表现出优于3DG/MnO2复合电极的电化学性能。另外,由3DG/CNTs/MnO2复合电极组装的非对称柔性超级电容器的能量密度和功率密度分别高达33.71Wh/kg和22727.3W/kg,而且基于3DG/CNTs/MnO2复合电极的对称和非对称超级电容器都表现出了高的能量密度保持率。此外,对组装的非对称超级电容器进行1000次循环测试后,其比容量保持率高达95.3%。本研究中提出的三元3D结构复合电极也可以应用于其他的高性能能量存储和转化系统。为了制备自支撑无粘接的超级电容器负极,我们首先在3DG上生长了ZnO纳米线,然后以ZnO纳米线为模板在含Fe3+的溶液中通过Fe3+的沉积和ZnO纳米线的溶解,在3DG上生长了Fe203纳米管(Fe2O3NTs)阵列。由于3DG和Fe2O3NTs独特结构的协同作用,所制备的3DG/Fe2O3NTs复合负极表现出了435mF/cm2的最高面积比容量。对3DG/Fe2O3NTs复合负极结构和性能的优化正在进行中,另外基于这种复合负极的柔性非对称超级电容器的组装还在探索中。
[Abstract]:Supercapacitor is a new energy storage device, as compared to the traditional parallel plate capacitor has higher energy density compared to the lithium ion battery has higher power density and longer life, and is widely studied. With the development of flexible electronics, flexible in super capacitor flexible display device, flexible storage has great application potentials system. Therefore, high performance lightweight flexible storage system has attracted more and more attention. The graphene based flexible supercapacitor because of its excellent properties has become a promising method.
In this paper, the thin nickel foam as a template and catalyst substrate, using CH4 as carbon source, by chemical vapor deposition (CVD) growth of graphene in the growth temperature of 1000 DEG C. Remove the foam nickel by HCl after corrosion, self supported flexible 3D graphene (3DG). Ultrathin (200 m) 3DG with low density (0.70-0.75mg/cm2). High conductivity (55S/cm), large specific surface area (392m2/g) and excellent flexibility and other advantages. Then we use electro deposition on the deposition of MnO2 prepared 3DG/MnO2 composite electrode. Because 3DG has great flexibility the specific surface area, it is an excellent base load MnO2, so as to ensure up to 9.8mg/cm2 MnO2 (full load electrode corresponding to the proportion of ~ 92.9%), in the scanning rate of 2mV/s was the highest in area 1.42F/cm2 than capacity. From a practical point of view, to optimize the MnO2 in the electrodes. The proportion and won the 130F/g electrode capacity. In addition, we will 3DG/MnO2 composite electrode sandwiched polymer diaphragm on both sides, forming a sandwich structure and outside PET plastic packaging and assembly quality of light in 10mg, flexible symmetric supercapacitor thickness to 0.8mm. The research for the realization of flexible, lightweight, provides the reference energy storage system with low cost and environment friendly.
In order to develop flexible supercapacitors with high power density, the growth of carbon nanotubes on 3DG (CNTs) network, flexible 3DG/CNTs/MnO2 composite electrode was prepared. The self support due to the introduced interconnected CNTs network, so the formation of a continuous three yuan 3D structure connection, thus constructing electronic and electrolyte fast ion diffusion channels in the composite electrode. Therefore, the preparation of 3DG/CNTs/MnO2 composite electrode prepared in specific capacity and rate characteristics have showed a better electrochemical performance than the 3DG/MnO2 composite electrode. In addition, the energy density and power density of unsymmetrical flexible supercapacitors assembled by 3DG/CNTs/ MnO2 composite electrode were as high as 33.71Wh/kg and 22727.3W/kg moreover, symmetric and asymmetric 3DG/CNTs/MnO2 composite electrode based on super capacitor showed a high energy density retention. In addition, the group. After 1000 cycles of asymmetric supercapacitors, the specific capacity holding rate is as high as 95.3%.. The three yuan 3D structure composite electrode proposed in this study can also be applied to other high-performance energy storage and conversion systems.
In order to prepare free-standing super capacitor anode without bonding, we first growth of ZnO nanowires on 3DG, then using ZnO nanowires as templates by Fe3+ deposition and dissolution of ZnO nanowires in solution containing Fe3+ and 3DG in the growth of Fe203 nanotubes (Fe2O3NTs) array. Because of synergistic effect of 3DG the unique structure and Fe2O3NTs, the prepared 3DG/Fe2O3NTs composite anode showed the highest specific capacity. The optimization area of 435mF/cm2 on the structure and properties of 3DG/Fe2O3NTs composite anode is underway, in addition still flexible assembly based on asymmetric supercapacitor this composite anode material for exploration.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM53

【共引文献】