应用于全固态锂电池的复合固态电解质研究进展

Research Progress of Composite Solid Electrolytes for All-Solid-State Lithium Batteries

基于固态电解质和锂金属负极的全固态锂离子电池能量密度高、安全性好,能够有效地抑制锂枝晶生长并改善电池的本征安全性。固态电解质作为全固态电池的关键材料,成为近年来的研究热点。目前,通过在聚合物基体中添加无机填料得到的复合固态电解质具有优异的力学性能和电化学性能,实现了对单一固态电解质体系的“取长补短”,被视为最具前景的电解质材料。在复合固态电解质中,无机填料与聚合物基体的两相界面对锂电池的离子电导率有重要贡献,但两相界面的增加受到无机填料渗流阈值的影响。因此,从填料的形貌、排列方式等方面优化渗流结构是进一步提高离子电导率的关键。基于以上问题,总结了各单一类型固态电解质以及复合固态电解质的特点及其导电机理,并基于不同维度的无机填料分析了复合固态电解质研究中的渗流结构设计思路、方法优劣及性能变化,并展望了复合固态电解质未来研究重点。

The all-solid-state lithium batteries using solid electrolytes and metallic lithium anode exhibit high energy-density and safety,and excellent ability to inhibit the growth of lithium dendrite and improve the intrinsic safety of batteries.Solid-state electrolytes as the key material have become one of the research hotspots for the past few years.The composite solid-state electrolytes obtained by dispersing inorganic fillers in the polymer matrix are the most promising electrdytes,because of their excellent mechanical and electrochemical properties.In the composite electrolytes,the interface between ceramic fillers and polymer matrixes exhibit a huge contribution to the ionic conductivity.However,the increase of the two-phase interface has a percolation threshold with the content increase of fillers.Therefore,it is important to optimize the percolation structure,dimension and arrangement of the fillers for the further improvement of the ionic conductivity.Herein,this paper summarizes the characteristics and Li-ion conductive mechanism of several solid electrolytes and composite solid electrolytes,analyzes different research ideas of percolation structure,methods and the performance of the composite solid electrolytes based on different dimensional inorganic fillers.At last,the bottleneck of designing percolation structures with inorganic fillers and the goal of future researches are prospected.