Nanomechanics of Brittle Solid Electrolytes—A Case Study on Garnets

Solid-state batteries employing lithium metal as a negative electrode promise high energy and safety. Plating at the lithium metal/solid electrolyte interface is fundamentally complex compared to plating in a liquid electrolyte due to mechanical considerations as well as heterogeneities. Ideally, lithium metal should plate densely in a planner fashion, growing away from the solid electrolyte. In reality, however, lithium plating is heterogeneous and can be directed towards the solid electrolyte, ultimately leading to short-circuit and penetration through the solid electrolyte. In this talk, I will overview our recent efforts to understand and control chemo-mechanics in garnet solid electrolytes. Specifically, we employ local electrochemical probes to correlate current-voltage behavior to defect and mechanical forces, both locally and macroscopically. Building on these fundamental understanding, I will show how interfacial engineering through coatings enable more uniform lithium plating.