【作者】 盛凯旋；

【导师】 石高全；

【作者基本信息】 清华大学 ， 化学， 2013， 博士

【摘要】 石墨烯因其独特的二维结构和各种优异的性能而在电子器件、复合材料、催化和能量存储等领域有着巨大的应用前景。石墨烯材料的性能依赖于它的形貌和结构。将纳米尺寸的石墨烯片构筑成高级有序的宏观组装体，不仅提供了多种调控其形貌和结构的手段，而且能够拓展石墨烯的功能和应用。本论文以石墨烯组装体的制备及其电化学应用研究为主题，以氧化石墨烯作为基本组装单元，采用不同的自组装策略制备了多种石墨烯组装体，并研究了它们在电致变色器件和超级电容器中的应用。主要研究内容和结果如下：结合层层自组装技术和氢碘酸还原氧化石墨烯的方法制备了石墨烯/PANI多层复合膜。该复合膜的厚度、透光率和表面电阻能够通过组装层数而非常容易地调控。石墨烯的加入提高了复合膜的导电性、机械柔韧性和电化学稳定性，使其能够用作不需要ITO基底的电致变色电极。具有15个双层的石墨烯/PANI复合膜表现出很好的电致变色性能和更好的电化学稳定性。采用抗坏血酸钠作为还原剂，通过化学还原氧化石墨烯一步法制备了高性能石墨烯自组装水凝胶。该方法具有绿色环保、节能省时、简便易行且能够规模化生产的优势。石墨烯水凝胶由规整的三维连通网络构成，不仅具有很好的导电性（3S/m）和力学性能（存储模量275kPa），而且还表现出优异的电容性能（240F/g）。此外，通过对反应条件和组装过程的研究，提出了石墨烯水凝胶的形成机理。在氧化石墨烯水溶液中，通过电化学还原氧化石墨烯一步法制备了三维多孔石墨烯电极。孔尺寸在微米至几十微米之间，且孔壁几乎垂直于集流体表面。石墨烯突出的导电性和电极“开放型”的孔结构非常有利于电子和电解质离子的传输，使基于该电极的超级电容器表现出超快速的充放电性能和很高的面积比电容。因此，它能够取代铝电解电容用于交流滤波。更多还原

【Abstract】 Owing to its unique two-dimensional structure and excellent properties,graphene has shown enormous potential applications in various fields, such aselectronic devices, composite materials, catalysts and energy storage, et al.Assembling graphene into macroscopic assemblies with hierarchical structures, notonly offers various methods to adjust the morphology and structure of grapheneassemblies, but also can improve their properties and extend their applications. In thisdissertation, we focus on the preparation of graphene assemblies and theirelectrochemical applications. Several macroscopic graphene assemblies wereconstructed through proper assembly strategies with graphene oxide as buildingblocks, and their electrochemical performances in electrochromic devices andelectrochemical double layer capacitors were investigated.Graphene/PANI multilayer films have been successfully fabricated by thecombination of LBL assembly and chemical reduction of grapheme oxide withhydroiodic acid. In addition, the thickness, conductivity and transmittance of themultilayer film can be easily tuned by changing the alternate deposition steps.Integration of graphene increased the conductivity, electrochemical stability andimproved the mechanical flexibility of the multilayer films, allowing it to be apromising electrode materials for electrochromic devices even without using ITO asthe supporting electrodes. The electrochomic device based on (graphene/PANI)15filmshowed good electrochromic performances and improved electrochemical stability.High-performance self-assembled graphene hydrogels were fabricated byone-step chemical reduction of graphene oxide with sodium ascorbate. This method isenvironmentally friendly, fast, energy saving, simple and readily scalable to industriallevels. The self-assembled graphene hydrogel, consisting of well-defined andcross-linked three dimensional porous structure, not only was electrically conductive(3S/m) and mechanically strong (storage modulus,275kPa), but also exhibited ahigh specific capacitance (240F/g) when used as electrode materials in supercapacitor. Furthermore, a mechanism of forming the self-assembly graphenehydrogels was proposed based on the study on the reaction condition and gelationprocess.Three-dimensional interpenetrating graphene electrodes were prepared byone-step electrochemical reduction of graphene oxide from its aqueous suspension.The pore sizes of the network are in the range of several micrometers to larger thanten micrometers, and the pore walls are nearly vertical to the surface of currentcollector. Because the high conductivity of graphene and interpenetratingmicrostructure of electrodes were convenient for electron/ion transportations, theinterpenetrating graphene electrodes based DLCs showed ultrahigh-rate capabilityand high specific capacitance. It was capable of replacing AEC for ac line-filtering.更多还原