On Modeling the Detrimental Effects of Inhomogeneous Plating-and-Stripping at a Lithium-Metal/Solid-Electrolyte Interface in a Solid-State-Battery

The understanding and modeling of the process of plating-and-stripping, and the effects of inhomogeneous deposition at a lithium-metal/solid-electrolyte (Li/SE) interface is still in its infancy. We have formulated a mechanics-based theory for modeling such a process, and we have numerically implemented the theory in a finite-element program. We demonstrate the utility of our simulation capability to model the process of plating-and-stripping of lithium, and also as a tool to analyze the detrimental effects of inhomogeneous deposition of lithium at chemical and geometric defects at a Li/SE interface, a circumstance which can result in the decohesion of the Li/SE interface, and/or mechanical fracture of the solid-electrolyte. Our numerical simulation capability should be of use in the design of lithium-metal-based next-generation energy storage devices. For instance, the simulation capability may be used (a) to determine the thickness of the ceramic SE to prevent its fracture; (b) to determine appropriate levels of cell stack-pressure to prevent decohesion of the Li/SE interface; and (c) to refine the design of novel ceramic-polymer composite electrolytes which have recently been proposed in the literature to overcome the fragility of monolithic thin-film ceramic electrolytes.