(Digital Presentation) Electrochemical-Mechanical Coupling between Single-Ion Conducting Electrolytes and Metal Electrodes

Abstract

Solid-state metal batteries provide increased gravimetric and volumetric energy density compared to conventional Li-ion batteries and their development is essential for meeting performance and cost targets for consumer applications. Conventional liquid electrolytes exhibit reactivity with pure Li and undergo significant dendrite formation, thus single-ion conducting solid electrolytes have been explored to prevent and mitigate dendrite formation as they possess high modulus, high room temperature ionic conductivity, and the potential to improve safety compared to organic liquid electrolytes. Unfortunately, ceramic single-ion conducting electrolytes such as LLZO have been demonstrated to form dendrites above critical current densities. Understanding the electrochemical-mechanical coupling between the electrolyte and electrode can help elucidate the mechanisms of dendrite formation and propagation in solid-state metal batteries as well as methods for prevention and mitigation. Mechanical stresses arise during battery operation due to external stack pressure, expansion and contraction of intercalation electrodes, and the deposition and stripping of metal electrodes. As we demonstrated in a previous work1, the thermodynamic state of the electrode is affected by its mechanical state, therefore, applied stresses alter the equilibrium potential of metal electrodes. Additionally, the mechanical state of the electrode can influence the metal electrode plating and stripping kinetics. Previous studies in the literature have examined the effect of mechanics on the current distribution; however, careful attention is required when coupling electrochemistry and mechanics as well as consideration as to the importance of the mechanical state of the electrolyte. This talk will focus on the effects of mechanical stresses on the current distribution at the metal electrode/single-ion conducting electrolyte interface and the implications on dendrite formation and mitigation.