Stability Criterion for Electrodeposition in Solid-State Batteries with Metallic Anodes

Abstract

We establish an analytical criterion for stable electrodeposition by combining electrochemistry and mechanics. In situ experiments combined with molecular simulations are performed to validate the robustness of the theoretical predictions. Our analysis shows that stable electrodeposition is intimately linked with the interfacial defect size, fracture toughness, and molar volume of solid electrolytes. We find an exponential scaling law between the critical current density and the interfacial defect size, and the inherent softening in strength of grain boundaries lowers the critical current density in polycrystalline solid electrolytes. Modeling and analyses provide roadmaps to design solid electrolytes with metallic anodes for achieving stable electrodeposition.