高Li+通量隔膜表面调控及锂离子电池电化学行为

The development of Li-ion battery with higher energy, power density and safety puts forward higher requirements for the R&D of separators. To reveal the affecting mechanism of micro/nano structures of separators on the kinetics of lithium-ion battery charging/discharging process will provide scientific guidance for the design and development of separators. This project aims to construct supramolecular films on the separator surface using layer by layer assembly, which offers the ability to exert molecular-level control over the surface characteristics of the separator by the selection of organic and inorganic building blocks. The interaction between the separator and electrolyte will be studied. Its effects on the ionic conductivity of the separator, Li-ion transference number and the separator/electrode interface compatibility will be clarified. The relationship between the kinetics process of the electrode/electrolyte interface and the ionic conductivity of the separator, Li-ion transference number and the separator/electrode interface compatibility will be elucidated. The affecting mechanism of the separator surface characteristics on the SEI film formation, the lithium dendrite growth, and the Li-ion intercalation/deintercalation kinetics process will be revealed. The achievements of the research will provide deep insight into the role of separators in the Li-ion battery, and more guidance to the design and optimization of separators, which is significant for the development of lithium ion batteries with high performances.

发展更高能量密度、功率密度和安全性的锂离子电池对新型隔膜的研发提出了更高的要求。揭示隔膜的微纳结构如何影响锂离子电池充放电的动力学过程对隔膜的设计开发具有重要的指导意义。本项目拟采用层层自组装法在聚烯烃隔膜孔表面构筑超分子膜，通过有机和无机构筑基元的选择精细调控隔膜的表面特性；研究隔膜/电解液间相互作用，明确其对隔膜的离子电导率、锂离子迁移数、隔膜/电极间界面性质的影响规律；阐明电池电极/电解液界面的动力学过程与隔膜的离子电导率、锂离子迁移数、隔膜/电极间界面性质之间的关系；揭示隔膜的表面特性影响电极/电解液界面SEI膜的形成、锂枝晶的生长、锂离子的嵌脱等动力学过程的机制。本项目的研究成果有助于从更微观层面上理解隔膜的表面结构及特性对锂离子电池电化学性能的作用机制，进一步指导隔膜体系设计及工艺优化，满足未来高性能锂离子电池对隔膜不断发展的需求。

本项目立足下一代高能量密度、高功率密度、高安全性锂离子电池对隔膜不断发展的需求，从微观尺度上深入研究了锂离子电池电极/电解液界面动力学过程与隔膜的物理化学性质，隔膜/电解液间相互作用，以及隔膜/电极间界面性质之间的关系，揭示出隔膜的表面结构组成对电解液中的离子传输性能存在显著影响，具有高锂离子通量的隔膜对锂离子电池理论容量的发挥具有重要作用，基于以上研究成果发表SCI论文9篇，其中影响因子大于5的8篇；申请相关发明专利5项，其中1项已获授权。本项目的实施启发我们去重新认识隔膜在锂电池系统中的角色和作用，为隔膜性能优化及产品开发提供了理论指导。