硅/碳互贯网络多孔复合材料的可控制备及在储能器件中的应用研究

"New energy vehicle" is a landmark of “New economy” in the field of industry, which greatly depends on the progress of batteries. Studies on silicon anode materials for lithium ion batteries are great significant for the development of new energy vehicles. However, at present silicon anode materials cannot really replace graphite carbon materials. In order to develop high performance lithium ion batteries, full coordination and optimization of nano size, pores, network and interface of silicon/carbon composite should be carried out through the innovation of the design and preparation of anode materials to achieve the controllable construction and accurate control of the composition, pore structure and silicon/carbon network. In this project, a new idea of controllable preparation of silicon/carbon interpenetrating porous network is proposed. By choosing appropriate silica source (silica gel nanotubes or silicon compounds), synthesizing a silicon/carbon block precursor through controllable polymerization, and followed by assembly of the block precursor, a predetermined silicon/carbon interpenetrating porous network can be obtained, which can also be controlled and inherited during carbonization and reduction process. Furthermore, the structure and properties of silicon/carbon anode materials can be optimized by adjusting the procedure and conditions of controllable polymerization and controlling the accurate assembly of silicon/polymer block precursor. As the result, high performance anode materials with full coordination and optimization of nano size, pores, network and silicon/carbon interface will be achieved.

新能源汽车是新经济在工业领域的标志性行业，而新能源汽车极大程度上依赖于电池的进步。锂离子电池的硅负极材料研究对推动新能源汽车发展有重要的意义。目前的硅负极材料还未能达到取代石墨碳材料的程度，必须通过创新材料设计和制备方法，实现组成、孔结构和硅/碳复合网络的可控构筑和准确控制，从而达到纳米化、多孔化、网络化、碳复合化的充分协调和优化，这是发展高性能锂离子用硅负极材料的有效路径。本项目提出硅/碳互贯多孔网络的可控制备的新思路，通过选择合适硅源（硅凝胶纳米管或硅化合物），经过可控聚合改性得到硅/碳嵌段前驱体，进一步组装得到预定孔结构的硅/碳互贯网络，最后在碳化和还原过程中实现硅/碳纳米结构和多孔网络的可控继承。调节可控聚合的工艺与条件及调控硅/碳嵌段聚合物前驱体的准确组装，可以达到优化硅/碳负极材料的结构和性能的目的，从而得到纳米化、多孔化、网络化、碳复合化充分协调和优化的高性能负极材料。

如今，新能源汽车是工业领域的一个关键行业，其发展极大程度依赖于电池工艺和技术的进步。因此，推动高性能锂离子电池负极材料的研究（例如硅负极材料）对促进新能源汽车的发展具有重要的意义。然而，目前的硅负极材料还未能达到取代石墨碳材料的程度，这是因为硅负极材料在实际使用过程存在导电性差和充放电过程体积变化大等问题。有鉴于此，本项目在硅/碳复合材料的网络化、纳米化和富孔化结构设计、可控制备以及构效关系等方面开展系统研究，获得了一系列高性能硅/碳复合负极材料。代表性研究成果包括：基于自凝胶的一维杂化分子刷制备了一类三维纳米网络氧化硅/碳复合材料，有效整合氧化硅和碳网络的结构优势，并通过协同效应使其表现出优异的储锂性能；发展了一种界面交联策略精确定制前驱体二维纳米形貌，从而设计制备了一类硅/硅氧碳复合二维纳米片，解决碳载体储锂性能有限的问题；利用协同组装策略，成功制备了具有三文治夹心结构的多组分复合纳米片。在本项目资助下，项目组成员在Nat. Commun.、Adv. Mater.、Mater. Today、Carbon、J. Mater. Chem. A和Chem. Commun.等期刊发表SCI论文19篇，在国内会议上发表论文13篇，申请发明专利7件。