Solid electrolytes have potential to dramatically improve energy density of batteries for demanding applications such as electrical vehicles by allowing the utilization of high energy density-Li metal anodes. However, harvesting the benefits of the solid electrolytes for Li-metal batteries is limited to due to interfacial instabilities, dendrite formation and large impedance. Chemo-mechanical deformations in the electrode- solid electrolyte interface are still the bottleneck to improve performance of solid-state batteries. It is critical to understand the governing forces behind the chemical and mechanical deformations during battery operation. The buried interface between Li metal and solid electrolyte presents challenges to probe dynamic changes in the interface during battery cycling. In this study, we utilized digital image correlation (DIC) to monitor chemo-mechanical deformations in solid-state batteries during battery cycling. A custom cell was designed to operate in operando strain measurements on solid electrolytes while cycling the all-solid-state battery1. Symmetrical Li | LAGP | Li cells were fabricated, and stainless-steel disks were used as a current collector. Here, we demonstrate experimental evidence for the correlation between overpotentials and mechanical deformations in the interface of solid electrolyte – Li metal. The increase in strains in the interphase layer coincides with the increase in overpotential. In situ strain measurements demonstrated the impact of the early non-uniform deformations on the spatial distribution of Li plating and stripping on the solid electrolyte – electrode interface. At the later cycles, large shear strains (∼0.75%) were generated in the middle of the solid electrolyte where fractures were detected by ex situ micro X-ray computed tomography. This work highlights the mechanical deformations in the LAGP/Li interface and its coupling with the electrochemical behavior of the battery.

Coupling between voltage profiles and mechanical deformations in the vicinity of Li Metal - LAGP solid electrolyte for all-solid-state batteries

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.