共价-有机框架化合物的设计、合成及其在新能源中的应用

In Li-S batteries, the physical absorption of sulfur into the nanodomins of porous materials can efficiently restrict the lose of soluble lithium polysulphides intermediates generated during the discharge process. However, we should mention here, the choosing of the porous materials is quite challenge. Therefore, it is very important to figure out how to rational design cathode materials in Li-S batteries. As a new type of organic porous materials, covalent-organic frameworks (COFs) have several advantages, such as low density, large surface area, highly porous ordered structure, facilely tailored functionality, and so on. In principle, COFs appear as suitable host for sulfur in Li-S batteries.In this proposal, we will investigate the application of COFs in Li-S batteries for the first time. In detail, we will 1) design and synthesize a series of COFs containing different functional units (e.g. porphyrin and pyrene) and having different pore size and volume; 2) prepare sulfur cathode for Li-S battery by using COFs as the host. From this study, we are trying to explore the structure and property relationships of COFs. Furthermore, we are going to systematically discuss how to rational design cathode materials in Li-S batteries.

锂硫电池中，通过物理吸附将硫固载于多孔材料的孔隙中，可有效改善充放电过程中产生的活性物质溶解流失问题。但是，多孔材料的选择带有一定的偶然性，载体与电池性能之间的关系仍缺乏足够的理性认识。因此，我们迫切需要去探讨：如何从分子层面上设计、构建适合锂-硫电池的载体材料，进一步形成对载体材料设计的系统性认识？作为一类新型的有机多孔材料，共价有机框架化合物（COFs）具有密度小、比表面高、孔结构高度有序、模块构筑多样化等特点。原理上讲，COFs可用作载体来负载硫单质并构建正极复合材料。本项目中，申请人拟首次研究COFs在锂硫电池中的应用：设计、合成含有不同功能性结构单元（如卟啉、芘）并具有不同孔径、孔容的COFs；进一步，以COFs为载体来固载硫单质并构建锂硫电池。申请人将探索COFs的结构-性能关系规律，并系统地探讨如何从分子层面上设计、构筑适合锂硫电池的载体材料。

经过四年的不懈努力，课题按计划进展顺利，各项研究任务得以落实和执行。发表通讯作者论文16篇，包括J. Am. Chem. Soc.（2篇）、Nature. Commun.（1篇）、Angew. Chem. Int. Ed. （2篇）、Sci. Adv.（1篇）、Adv. Mater. （1篇）、J. Mater. Chem. A（2篇）等。取得了如下的研究成果：1）设计合成了系列功能二维COFs，进一步构筑了高稳定性的锂硫电池；2）设计合成了系列功能三维COFs，提出了构筑三维COF的拓扑设计新策略。在本项目的资助下，我们对COFs的设计、合成及应用有了较深刻的认识，研究成果也获得了国内外同行的广泛关注，他引最高225次并被Science等杂志引用。此外，我们还在响应性金属-有机框架化合物（MOFs）做了一些工作，提出了简单、高效构筑MOF可控药物释放体系的新思路以及荧光光诱导电子转移固态调控的新策略。