同步辐射谱学研究无序富锂氧化物正极材料的构效关系

The design of high-performance cathode materials is the key in the development of lithium-ion batteries (LIBs). In recent years, the emergence and improvement of new cathode materials offers the hope to get high-performance lithium-ion power batteries of next generation. Among them, disordered lithium-rich oxide with high capacity as novel potential cathode, is greatly attracting our attention. This kind of material can not only overcome the capacity fade caused by cation-disorder behavior in traditional layered materials, but also stable the O-O peroxo-like dimers formed in the charge/discharge process, which provides excess considerable capacity from the reversible oxygen anionic redox. Here, Li-Ni-Ru-O disordered oxide system has been selected to develop synchrotron-radiation-based (SR-based) in-situ X-ray absorption spectroscopy (XAS), combined with multiple scattering ab initio theory to study the internal structure’s evolution of high capacity disordered lithium-rich oxide during charge/discharge process in the electronic/atomic scale, especially the migration path which the anionic takes part in, to sufficiently understand the interaction between all the redox couples and their corresponding effect to lithium ions’ migration. The relationship between the microstructure evolution and the performance of battery observed by the real-time technology, will solidate the foundation of the design and development of high capacity novel disordered lithium-rich cathode material.

正极材料是锂离子电池的关键，近年来不断涌现和改进的正极材料为研发下一代高性能动力锂离子电池带来希望。其中，高容量无序富锂氧化物作为新型的极有潜力的锂离子电池正极材料，正在受到人们热点关注。此类材料不仅可以克服传统层状材料在充放电过程中发生的阳离子无序导致的容量衰退，而且其结构可以稳定充放电过程中形成的O-O二聚体，使得材料中阴离子氧能够可逆地发生氧化还原反应，从而额外提供相当可观的容量。本项目选取Li-Ni-Ru-O无序氧化物体系，发展完善同步辐射原位X射线吸收谱学测试技术，结合多重散射从头计算理论，在电子和原子尺度上研究高容量无序富锂氧化物正极材料在充放电过程中内部结构的微观演化，特别是阴离子氧所参与的演化路径，以充分理解各氧化还原电对之间的相互作用及对锂离子迁移的影响。实时观察的微观结构演化和电池性能之间的关系，将为高容量新型无序富锂正极材料的设计和开发打下坚实的基础。

正极材料是锂离子电池的关键，近年来不断涌现和改进的正极材料为研发下一代高性能动力锂离子电池带来希望。其中，高容量无序富锂氧化物作为新型的极有潜力的锂离子电池正极材料，受到人们热点关注。此类材料不仅可以克服传统层状材料在充放电过程中发生的阳离子无序导致的容量衰退，而且其结构可以稳定充放电过程中形成的O-O二聚体，使得材料中阴离子氧能够可逆地发生氧化还原反应，从而额外提供相当可观的容量。本项目选取Li-Ni-Ru-O无序氧化物体系，发展完善了同步辐射原位X射线吸收谱学测试技术，结合多重散射从头计算理论，在电子和原子尺度上研究了高容量无序富锂氧化物正极材料在充放电过程中内部结构的微观演化，特别是阴离子氧所参与的演化路径，以充分理解各氧化还原电对之间的相互作用及对锂离子迁移的影响。实时观察了微观结构演化和电池性能之间的关系，并设计合成了若干高容量新型二次电池正极材料。.相关研究成果发表在Journal of Power Sources、 Electrochimica Acta等期刊上，授权实用新型专利一项，发明专利正在申请过程中。.本项目联合培养了博士研究生3名。项目执行期间，共参加国内外国际学术会议5人次，召集学术论坛1次。