Chemo-Mechanical Characterization of Lithium-Ion and Lithium Metal Batteries Using Operando Acoustic Scanning

Spatially sensitive operando characterization techniques provide fundamental insights into dynamic and complex electrode phase behaviors of electrochemical cells during operation. However, real-time characterization of cell-level behavior is challenged by low sensitivity to lithium and the need for high spatial and temporal resolution. First, I will demonstrate an operando acoustic scanning technique to detect local variations in phase behavior for the entire cell area during charging at all practical rates. Lithium plating and spatial variations in graphite lithiation for lithium-ion cells can be imaged during fast-charging. Second, I describe the capability of acoustic scanning to image the rate of electrolyte wetting propagation and lithium deposition in NMC811/Cu anode-free lithium metal cells. Third, the operando acoustic technique is coupled with solid-state nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) to characterize the chemo-mechanical changes, such as void formation and crack propagation, in LLZO solid-state batteries.