(Invited) Computational Modeling of Void Formation Mechanism at the Lithium/Solid-Electrolyte Interface

Abstract

Stabilization of the lithium deposition by the introduction of solid electrolytes was attempted in the past with partial success. However, electrochemical dissolution of lithium from the metal electrode to the solid electrolyte introduces unique challenges, such as, formation of micron sized voids at the electrode/electrolyte interface. These interfacial pores form due to stripping of lithium at a rate higher than they can actually be replenished from the bulk. Presence of these porous domains will minimize the electrochemically active surface area, dramatically increase the interfacial resistance, and effectively render the cell unusable. In the present research, a phase field based computational framework is developed that can capture the evolution of these micron sized voids at the lithium/solid-electrolyte interface during the electrochemical dissolution of lithium. Importance of lithium surface diffusion in determining the pore morphology is introduced for the first time. Impact of applied current density, external pressure, and operating temperature on the dynamics of void evolution is investigated in detail. Figure 1