模板辅助组装法构筑三维多孔石墨烯及其复合物功能材料

Graphene is a two-dimensional nanomaterial with unique nanostructures and excellent physical and chemical properties. However, graphene sheets tend to form agglomerates, resulting in limitation of its practical application. Self-assembly of two-dimensional graphene sheets is an important strategy for producing macroscopic graphene three-dimensional porous networks architectures with high surface area, which makes them with extraordinary potential in terms of energy storage, adsorption, and catalysis etc.. This project is to build a low-cost and simple method for preparing a 3D graphene and its composites functional materials using 2D graphene nanosheets via template-assisted assembly process. The topics include: the preparation of graphene oxide monomers and the choice of the template; the forming mechanism of the monomers adsorption in the limiting surface or filling in the space of the templates, and the assembly process formation mechanism of the three-dimensional structure; controlling the ordered pore structures of the assembly system as well as effectively removing the oxygen groups during the reduction process; chemical doping and chemical activation to form nano-pore structure on the surface of the three-dimensional graphene; preparation and combination of the three-dimensional graphene composites together with their components utilizing their synergistic effects. The project aims to introduce the new template-assisted assembly techniques to control and build macroscopic three-dimensional graphene and their composites materials with special functional structures, providing basic theory and technology to promote the practical application of graphene industry.

石墨烯是一种二维纳米材料，具有独特的纳米结构及优异的物理化学性能。然而石墨烯极易发生团聚而限制了它的实用化。构造三维石墨烯多孔网络结构是一种可以确保其高比表面积的重要策略，使其在储能、吸附、催化等方面具有非凡的应用潜力。本项目通过模板的辅助组装技术将石墨烯单体组装在一起构筑三维石墨烯多孔网络结构，旨在建立一种成本低廉、工艺简单的制备三维石墨烯及其复合物功能材料的方法。具体内容包括：氧化石墨烯单体的制备及模板的选择；单体在模板表面或其限制空间的吸附、填充、组装过程及结构的形成机制；体系有序孔结构的控制及含氧官能团的有效去除；三维石墨烯的元素掺杂及表面化学改造形成纳米孔结构；三维石墨烯复合材料的制备及表面与负载组分之间协同效应的应用。本项目旨在引入新型模板辅助组装技术，实现可控构筑具有特殊结构宏观三维石墨烯功能材料及功能复合材料，为推动石墨烯产业的实用化提供理论和技术的支持。

三维石墨烯结构的独特性能使其在储能、吸附、催化等方面具有非凡的应用潜力。本项目通过对石墨烯的模板辅助组装及调控，并结合水热法和原位化学气相沉积技术构筑三维石墨烯及其复合物功能材料，以实现其在锂离子电池、锂硫电池及钠离子电池方面的应用。主要成果包括（1）以三聚氰胺海绵为模板并结合水热及高温处理过程，制备了氮掺杂石墨烯@MoS2多级微管结构，将其用于钠离子电池的负极材料，表现出稳定的循环性能，以及优良的倍率性能。在100 mA/g和1 A/g的电流密度下，循环100圈后仍然有407mAh/g和391mAh/g的放电比容量；（2）提出了一种通过原位化学气相沉积技术，一步还原氧化石墨烯并原位负载ZnO纳米颗粒，合成氮掺杂石墨烯微米带@ZnO纳米复合材料，表现出优异的电化学储锂性能，在0.2 A/g的电流密度下，250次循环后仍保持有728.4 mAh/g可逆放电容量，即使在高倍率5 A/g，仍然有406.1 mAh/g可逆比容量。；（3）设计制作了形貌可控的三维氮掺杂石墨烯海绵，用于锂硫电池，具有较高的放电容量、良好的倍率能力和优异的循环稳定性，在电流密度为0.1，0.2，0.5，1，2 C时，其平均可逆比容量分别为819.8，722.7，629.1，565.4，495.5 mAh/g。本项目的开展对于推动石墨烯的实用化研究具有一定的理论指导意义和重要的实际应用价值。