Mapping and Modeling Physicochemical Fields in Solid-State Lithium Metal Batteries

The safety and energy density of solid-state batteries can be, in principle, substantially increased compared with conventional batteries. However, the use of solid-state electrolytes introduces pronounced complexities to the solid-state system because of the strong coupling between different physiochemical fields. This necessitates the development of experimental and theoretical methods to directly trace the evolution of electrochemical, stress, crack and thermal fields upon battery cycling, to fully understand the electrochemical processes. In this talk, I will discuss imaging tools that are developed in our group to track the electrochemical reaction fronts (i.e., electrochemical deposits of lithium metal), stress and crack evolution in 3D during processing and cycling of solid-state lithium metal batteries. We show that the crack formation and stress distribution in solid-state electrolytes are extremely sensitive to the preparation conditions, which, in turn, affect the electrochemical performance of batteries. Further, these imaging data can be combined with theoretical efforts to develop electromechanical and/or electrothermal models for solid-state lithium metal batteries. These works provide a strong basis to understand the strong coupling between different physiochemical fields, a prerequisite to fully unlock the potential of solid-state lithium metal batteries.