Visualizing the failure of solid electrolyte under GPa-level interface stress induced by lithium eruption

Haowen Gao; Xin Ai; Hongchun Wang; Wangqin Li; Ping Wei; Yong Cheng; Siwei Gui; Hui Yang; Yong Yang; Ming-Sheng Wang

doi:10.1038/s41467-022-32732-z

Visualizing the failure of solid electrolyte under GPa-level interface stress induced by lithium eruption

Nat Commun. 2022 Aug 27;13(1):5050. doi: 10.1038/s41467-022-32732-z.

Authors

Haowen Gao¹, Xin Ai², Hongchun Wang³, Wangqin Li¹, Ping Wei¹, Yong Cheng¹, Siwei Gui², Hui Yang⁴, Yong Yang³, Ming-Sheng Wang⁵

Affiliations

¹ State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Materials, Xiamen University, 361005, Xiamen, China.
² State Key Laboratory of Material Processing and Die & Mould Technology, Department of Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
³ State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen, 361005, Fujian, China.
⁴ State Key Laboratory of Material Processing and Die & Mould Technology, Department of Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China. huiyang2017@hust.edu.cn.
⁵ State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Materials, Xiamen University, 361005, Xiamen, China. mswang@xmu.edu.cn.

Abstract

Solid electrolytes hold the promise for enabling high-performance lithium (Li) metal batteries, but suffer from Li-filament penetration issues. The mechanism of this rate-dependent failure, especially the impact of the electrochemo-mechanical attack from Li deposition, remains elusive. Herein, we reveal the Li deposition dynamics and associated failure mechanism of solid electrolyte by visualizing the Li|Li₇La₃Zr₂O₁₂ (LLZO) interface evolution via in situ transmission electron microscopy (TEM). Under a strong mechanical constraint and low charging rate, the Li-deposition-induced stress enables the single-crystal Li to laterally expand on LLZO. However, upon Li "eruption", the rapidly built-up local stress, reaching at least GPa level, can even crack single-crystal LLZO particles without apparent defects. In comparison, Li vertical growth by weakening the mechanical constraint can boost the local current density up to A·cm^-2 level without damaging LLZO. Our results demonstrate that the crack initiation at the Li|LLZO interface depends strongly on not only the local current density but also the way and efficiency of mass/stress release. Finally, potential strategies enabling fast Li transport and stress relaxation at the interface are proposed for promoting the rate capability of solid electrolytes.

Abstract

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