Combining Operando Techniques to Probe Chemo-Mechanical Evolution at Buried Solid/Solid Interfaces

Abstract

Chemical and mechanical changes local to the electrode/electrolyte interface critically impact performance in all-solid-state batteries. Unfortunately, the dynamics at electrochemical interfaces are exceptionally challenging to probe in all-solid-state batteries because these changes take place across multiple length scales (from the nano- to meso-scale) and are buried within the system (at the solid/solid electrode/electrolyte interface). Here, I show our efforts to couple operando acoustic transmission measurements with nuclear magnetic resonance spectroscopy and imaging to correlate changes in interfacial mechanics with the growth of Li microstructures and the solid electrolyte interphase (SEI) in a non-invasive, multimodal fashion. Specifically, we study chemo-mechanical changes at the interface between Li metal anodes and Li7La3Zr2O12 solid electrolytes as a function of stack pressure and current density.