Void Growth Dynamics in Solid-State Batteries

Abstract

Solid-state batteries (SSBs) can potentially offer improved energy density and safety, when compared to current lithium-ion batteries. Despite their irrefutable theoretical promise, further advancement of SSBs relies on developing a comprehensive understanding of various fundamental aspects including electro-chemo-mechanics, transport interactions, morphological evolution and related failure modes at solid-solid interfaces. Amongst the wide range of challenges, the formation and evolution of interfacial voids at the lithium-metal/solid-electrolyte interface during stripping is critical, due to its associated effect on internal short-circuit and cell failure during subsequent plating. The void growth phenomenon in SSBs is jointly determined by different factors such as the self-diffusion kinetics and mechanical response of lithium, reaction distribution at the solid-solid interface, and operating conditions such as external pressure and temperature. In this presentation, the pivotal role of reaction heterogeneity on the contact evolution process, along with key descriptors such as the lithium microstructure, surface morphology and contact percolation are discussed. The underlying asymmetry in terms of the competing electrochemical/mechanical processes and contact evolution during plating and stripping is highlighted. Lastly, the influence of non-uniformities in external pressure and temperature on the occurrence of disparate void growth patterns and electrochemical response is examined in this presentation.