石墨烯纳米片多级结构的构建活化及其超级电容行为研究

It is one of the main trends to develop the electrode materials with high electrochemical performance for supercapacitor. Graphene nanosheets with 2-D structure are very promising as novel electrode materials in supercapacitors. However,the low bulk conductivity and small effective surface area are two key scienctic issues which have restricted the practical appliction in supercapacitors.In this project, a new proposal which combines building and activation of 3D hierachical structures with graphene nanosheets is proposed to solve these two issues. One hand, the building of hierachical structures help to improve the conductivity between the graphene nanosheets, leading to the enhancement of bulk electric conductivity. On the other hand, the activation of graphene nanosheets will introduce suitable micropore and mesopores,which is favorable to the increase of effective surface area. Herein, the microstructure of graphene nanosheets will be controllably modified through "building and activation", and the rules and relationships between the microstructures of graphene and electrochemical performance will be studied.After optimizing the experimental parameters, we are aiming to obtain activated graphene nanosheets with 3D hierachical structures, which possess good electrochemical performance. The microstructure modification method for graphene proposed is favorable to improve the electrochemical performance,enrich and develop the theory of graphene building and activation, and facilitate the practical application for graphene nanosheets.

发展新型高性能电极材料，是当今超级电容器主要研究方向之一。石墨烯纳米片是一种非常有潜力的新型超级电容电极材料，然而体电导率低和有效比表面积小是限制其应用于超级电容器中的两大关键科学问题。本课题提出通过构建3D多级结构结合活化法以解决这两个关键科学问题，多级结构的构建，可以提高纳米片间电导率，从而提高体电导率；活化处理将使石墨烯生成适合的微介孔结构，从而增加有效比表面积。通过"构建-活化"调控石墨烯微观结构，研究微观结构与超级电容行为之间关系规律，优化实验，制备出具有高性能的多级结构的活化石墨烯纳米片。本课题提出的石墨烯微观结构调控方法，有助于大幅度提高超级电容器电极材料的性能，丰富和发展石墨烯构建及活化理论，早日实现石墨烯在超级电容器中的应用。

石墨烯材料是一种非常具有潜力的电极材料，在超级电容器等储能器件领域具有广泛的应用前景。本课题主要研究了石墨烯及其复合材料在超级电容器，锂离子电池等方面的性能，研究表明石墨烯的活化温度，制备方法及掺杂对其电化学性能有极大的影响：活化温度升高，有利于提高石墨烯的比表面积，活化温度为大约700摄氏度时制备的材料具有较高的比表面积和最大的比电容；一定量的氮掺杂有利于提高石墨烯材料的电化学性能，氮掺杂石墨烯/氮掺杂TiO2材料不仅表现了良好的比容量，而且具有优良的倍率性能和循环性能；研究还表明“弯曲”的石墨烯比“平面”石墨烯具有更好的循环稳定性和倍率性能。本项目的研究进一步深化了对石墨烯纳米片微观结构，杂原子掺杂等与电化学性能之间的内在关系的理解，为进一步开发高性能石墨烯基材料及石墨烯基复合材料打下了较好的基础。