石墨烯气凝胶的可控制备及其弹性机理研究

Graphene aerogel is one of the most important macroscopic graphene-based materials. It shows high electronic conductivity, high elasticity, and low density, which are desirable properties for its applications in electrode, sensor, photocatalysis, and nanocomposite. So far there are two key scientific issues in this field including controlled fabrication of graphene aerogel and its elasticity mechanism study. Firstly, this proposal will focus on the controlled fabrication of graphene aerogels with fine microstructures and excellent properties, which are studied in three aspects by considering the structure of single layer graphene oxide, the mesophase structure of graphene oxide in the dispersed solution, the macroscopic porous structure of graphene aerogel. Secondly, elasticity mechanism of graphene aerogel will be studied systematically by considering the multiscale effect. In addition, the graphene aerogels with special cone structure will be designed and a unique in-situ SEM technique will be used to observe the compression-release behavior, which will provide direct experimental evidence of elasticity mechanism. The complete understanding structure-function relations will enable the controlled fabrication of graphene aerogels with high elasticity, high anti-fatigue and ultra-flyweight. A better understanding of elasticity mechanism of graphene aerogel provides the theoretical guidance for its potential applications in electro-catalysis, electromagnetic shielding, and flexible electrode.

石墨烯气凝胶是一类非常重要的石墨烯宏观材料。它具有高导电性、高弹性、低密度等特点，在电极材料、传感器、光催化、纳米复合材料等领域具有重要的应用前景。目前该领域还存在两个重要的科学问题，即石墨烯气凝胶的可控制备和相关弹性机理研究。本项目拟从单层氧化石墨烯的结构、分散液的聚集态以及石墨烯气凝胶的宏观多孔结构制备过程等三个不同层面对石墨烯气凝胶的精细微结构和宏观性能实现可控制备。从多尺度协同作用的角度对石墨烯气凝胶的弹性机理进行系统深入研究。设计锥形等定制结构的石墨烯气凝胶，利用扫描电镜表征手段对单片或多片石墨烯的压缩回弹行为进行原位观测，为确定弹性机理提供直接的实验证据。阐明结构-性能关系的规律，最终实现超高弹性、高耐疲劳性、超轻石墨烯气凝胶的精细可控制备和对弹性机理的深入认识，探索石墨烯气凝胶在电催化、电磁屏蔽、柔性电极方面的应用。

石墨烯气凝胶具有低密度、高弹性、比表面积大等特点，在电极材料，传感，电磁屏蔽等领域具有广泛的应用。本项目针对石墨烯气凝胶的可控制备、弹性机理以及相关应用展开研究。从石墨烯化学出发，考察单层氧化石墨烯的性质、分散液及其组装过程中的参数和后处理条件对石墨烯气凝胶微结构的影响，建立可参数化的稳定可控制备体系。并进一步考察上述参数对石墨烯气凝胶性能（如弹性）的调控，利用扫描电子显微镜手段跟踪气凝胶的压缩回弹行为，进一步总结规律，弄清结构和性能之间的关系，确认弹性机理。最终探索超弹性石墨烯气凝胶在力学、电学、电磁屏蔽、电极材料等领域的应用。具体来说，提出“湿法纺球”组装法，实现了具有团体效应和多功能的超弹性石墨烯气凝胶球的连续制备，多个球的组装体表现出比拟于单个球的优异性能；利用石墨烯/碳纳米管二元协同作用，进一步提高气凝胶球的弹性，探索了其在应力传感器、吸附、电极材料等领域的应用；通过构筑仿贝壳结构的石墨烯气凝胶导电网络，获得了具有高电磁屏蔽性能的石墨烯气凝胶复合材料，在极低石墨烯含量下（~0.42 wt%），电磁屏蔽性能可达到65 dB；此外，对石墨烯气凝胶的弹性机理进行了探索研究发现，石墨烯气凝胶的力学性能与其组装单元的固有性质紧密相关。项目执行期间，以第一作者/通讯作者身份，发表经费标注的SCI论文共7篇，包括Advanced Materials 1篇，ACS Nano 2篇，Carbon 3篇等。授权中国发明专利1项。