In Situ Investigation of Chemomechanical Effects in Thiophosphate Solid Electrolytes
In Situ Investigation of Chemomechanical Effects in Thiophosphate Solid Electrolytes
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DOI：
10.1016/j.matt.2020.09.018
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发表时间：
2020-12-02
期刊：
影响因子：
18.9
通讯作者：
Hatzell, Kelsey B.
中科院分区：
文献类型：
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作者：
Dixit, Marm B.;Singh, Nikhilendra;Hatzell, Kelsey B.
在高电流密度下，固态电池可能由于固体电解质断裂、界面分解或锂丝生长而遭受灾难性的故障。失效与电化学循环过程中材料的化学力学转变有关。我们系统地研究了固体电解质微观结构和界面分解（例如，界面相）如何影响硫代磷酸锂（Li3PS4， LPS）电解质的失效机制。用碘掺杂设计了动力学亚稳态界面，并使用铣削和退火处理技术实现了微观结构控制。原位透射电镜显示碘向间相扩散，电化学循环后，在间相区域形成孔隙。原位同步加速器层析成像显示，相间孔隙形成驱动边缘断裂事件，这是穿面断裂破坏的根源。硫磷电解质中的裂缝主动向孔隙度较高的区域生长，并受到微观结构非均质性（如孔隙度因子）的影响。这项工作为高性能固态电池提供了基本的设计指南。
Solid-state batteries can suffer from catastrophic failure at high current densities due to solid electrolyte fracture, interface decomposition, or lithium filament growth. Failure is linked to chemomechanical material transformations that can manifest during electrochemical cycling. We systematically investigate how solid electrolyte microstructure and interfacial decomposition (e.g., interphase) affect failure mechanisms in lithium thiophosphates (Li3PS4, LPS) electrolytes. Kinetically metastable interphases are engineered with iodine doping, and microstructural control is achieved using milling and annealing processing techniques. In situ transmission electron microscopy reveals iodine diffusion to the interphase, and upon electrochemical cycling, pores are formed in the interphase region. In situ synchrotron tomography reveals that interphase pore formation drives edge fracture events, which are the origin of through-plane fracture failure. Fractures in thiophosphate electrolytes actively grow toward regions of higher porosity and are affected by heterogeneity in microstructure (e.g., porosity factor). This work provides fundamental design guidelines for high-performance solid-state batteries.