Mechanical Failure of Solid-State Electrolyte Rooted in Synergy of Interfacial and Internal Defects

摘要

The mechanical failure of solid-state electrolytes induced by the growth of thelithium metal anode hinders the development of solid-state Li metal batterieswith good safety and high energy density, and thus the understanding of thefailure mechanism is of high importance for the application of solid-statelithium-metal batteries. Herein, a modified electro-chemo-mechanical modelis built to bridge the dynamic relationship between the mechanical failureof solid-state electrolytes and the electrodeposition of lithium metal. Theresults, visualize evolution of local stress fields and the corresponding relativedamage, and indicate that the generation of damage inside the solid-stateelectrolyte is rooted in a synergy of interfacial and internal defects. Compressionby electrodeposited lithium inside interfacial defects and further transmissionof stress inward in the electrolyte causes catastrophic damage, whichis determined by the geometry of interfacial defects. Moreover, the internaldefects of the solid-state electrolyte from sintering can influence the pathwayof damage and work as the inner fountainhead for further damage propagation,and as such, the position and amount of the internal voids exhibit amore competitive role in the mechanical failure of solid-state electrolyte.Thus, the synergetic failure mechanism of solid-state electrolytes raised inthis work provides a modeling framework to design effective strategies forstate-of-the-art solid-state lithium-metal batteries.