基于paddle-wheel机制的高离子电导率固态电解质的研究

全固态电池比传统液态电池具有更高的理论能量密度和更好的安全性能，是最具有潜力的下一代储能技术。固态电解质作为固态电池的核心组成部件，其离子电导率和电化学性能很大程度上决定了固态电池的功率密度和循环稳定性。正确认识固体材料内部的离子输运机制，是设计和制备高离子电导率材料的关键。申请人在前期工作中发现[PS4]聚阴离子在室温下能发生转动，且通过打开钠离子扩散所需要跨越的三角形瓶颈，从而降低钠离子跃迁势垒。本申请基于申请人前期的积累，拟研究双阴离子电解质中阴离子的转动现象，研究自由体积、阴离子种类、晶体结构等对阴离子转动行为的影响，结合分子动力学模拟，核磁共振和中子衍射最大熵法分析等，阐明引起聚阴离子转动的本质原因及影响其激活温度的关键因素，进而为设计新型高离子电导率的电解质材料提供理论支撑和指导原则。

All-solid-state batteries (ASSBs) based on Li/Na metal is one of the most promising next-generation energy storage techniques as it potentially offers higher energy density and better safety compared to conventional Li ion batteries. As the most important component in ASSBs, solid electrolytes mostly determine the power density and cycling performance. Understanding the underlying ion conduction mechanism presents significant importance, as it can provide guideline for the design of highly conductive solid electrolytes. We have previously reported that [PS4] and [PSe4] polyanions exhibit facile rotation in thiophosphates and enhance cation mobility by transiently opening up the bottleneck for cations to squeeze through. The polyanion rotational behavior in other solid electrolytes, such as composites is yet to be studied. In this project, the impact of free volume, anion species, crystal structure on polyanion rotation will be studied with the joint utilization of AIMD simulations, NMR and MEM analysis based on neutron diffraction technique. We aim to figure out the driving factor for polyanion rotation and the key that determines the onset temperature, based on which guideline for the design of new fast ion conductors are expected to be proposed.