Mechanism of Void Formation in Lithium Metal Solid-State Batteries

Abstract

Solid-state batteries (SSBs) with lithium metal anodes promise higher energy and power density over conventional lithium-ion batteries. But the development of SSBs faces fundamental challenges related to the electro-chemo-mechanics and stability of solid-solid interfaces. Among these, the formation and growth of voids at the lithium metal-solid electrolyte interface during stripping persists to be a major limitation. In this work, we analyze the nature of metal electro-dissolution and its critical implication on the evolution of solid-solid point contacts. The competing nature of lithium self-diffusion, reaction kinetics and ionic transport at the solid-solid interface, dependent on factors such as temperature and surface roughness are examined. Hotspots in the dissolution morphologies are identified and systematically connected to the electrochemical signature and onset of failure in SSBs.