Chemomechanics of Lithium Batteries via Operando Acoustics
Gunnar Thorsteinsson, Earth and Environmental Engineering
Abstract: This dissertation explores the application of acoustics as a characterization technique for three anode materials in lithium-based battery systems. The first focus is on the formation process of anode-free lithium metal batteries, examining how various parameters and properties influence lithium metal plating and stripping dynamics. Across three interconnected chapters, the key finding is that higher current density on formation supports cycling performance. Graphite is the second anode material, with a special consideration of observing its staging behavior. This is done using resonance, a novel method for extracting acoustic features of battery systems where conventional “chirping” falls short. The third and last anode material is silicon. Paired with a solid-state electrolyte, its phasing dynamics, expansion, and pitting are observed in the chemomechanical domain.