二维多孔石墨烯材料的微波控制氧化制备及其在全固态锂电池中的应用探索研究

Due to the good electric / thermal conductivity and the two-dimensional nanostructure, the graphene provides good conductive network in electrodes, and also protects the active material by coating, thus contributing to electrode kinetics and battery cycle-stability. Recently, the "graphene battery" is sensational, but essentially it is a graphene-based lithium-ion battery with small amount of graphene added in electrodes. From the viewpoint of ion transport, however, the graphene with two-dimensional structure hinders and slows the transport of ions in the electrode, which is adverse to fast ionic transport and electrode dynamics. So, the actual effect of graphene additive for batteries should be discounted. On the basis of literature and our previous work, it is suggested that in the graphene sheet “chisel” out of a large number of depth-through nano-holes can help the ions transport through these nano-holes, and significantly enhance ion transport efficiency and electrode dynamics. Therefore, the two-dimensional holey graphene technology is an effective solution to improve graphene additive in terms of ionic transport. Presently, the methods of preparation of such two-dimensional holey graphene in literature are time-consuming, high-energy consuming, and environmentally unfriendly. To address this problem, we will study the preparation of the holey graphene in ambient air by means of microwave controlled oxidation, elucidate the method for the preparation and regulation of holey graphene, reveal the influence on the conductivity of HG, and explore the application of HG in all-solid-state lithium batteries. We will also study the interfacial issues of HG with solid-electrolyte and active material. This project will lay a foundation for the development of the novel conductive additive of holey graphene, and also has practical significance to the promotion of all-solid-state lithium batteries.

石墨烯具有良好的导电/导热性和二维纳米结构，可为极片提供好的导电和导热网络，还可通过包覆来保护活性材料，有助于电极的动力学和循环稳定性。石墨烯导电剂已经受到很大关注，如最近热炒的“石墨烯电池”实质就是石墨烯基电池。然而从离子输运角度看，石墨烯的离子通透性差，不利于离子快速输运。石墨烯导电剂的实际作用将打折扣。文献和申请人以往的研究表明在石墨烯片“凿”出大量洞穿的纳米孔，离子经孔穿越而不必绕行石墨烯片，可提高离子输运效率。二维多孔石墨烯（HG）技术是改善石墨烯离子通透性的有效方案。目前文献制备HG存在耗时、耗能，且环境不友好的问题。为解决该问题，本项目拟开展微波控制氧化制备HG的研究，阐明该方法制备和调控HG的规律，揭示影响HG导电性的因素。探索HG在全固态锂电池中的应用，研究HG与固态电解质、活性材料之间的界面问题。本项目为开发HG新型导电剂奠定基础，对促进全固态锂电池的发展具有实际意义。

本项目提出并研究了石墨烯/微波作用体系及其应用策略，这包括基于石墨烯/微波作用，提出并演示了二维多孔石墨烯的快速制备、石墨烯的N、B、P等元素的快速掺杂、超细化石墨烯/硫复合电极的快速制备，以及一种新型储热机制。本研究成果有望开启多孔石墨烯的规模化制备及其应用，以及石墨烯/微波作用体系本身在储能和材料合成等领域的应用研究。在本项目资助下共发表了14篇SCI文章，申请了8项发明专利，其中1项获得正式授权，3项获得实施许可。基于本项目研究成果，成功获得“多孔石墨烯（基）超级电容器”横向项目。