6 research outputs found
Mechanism of Lithium Metal Penetration through Inorganic Solid Electrolytes
Li deposition is observed and measured on a solid electrolyte in the vicinity of a metallic current collector. Four types of ion-conducting, inorganic solid electrolytes are tested: Amorphous 70/30 mol% Li2S-P2S5, polycrystalline ÎČ-Li3PS4, and polycrystalline and single-crystalline Li6La3ZrTaO12 garnet. The
nature of lithium plating depends on the proximity of the current collector to defects such as surface cracks and on the current density. Lithium plating
penetrates/inïŹltrates at defects, but only above a critical current density.
Eventually, inïŹltration results in a short circuit between the current collector and the Li-source (anode). These results do not depend on the electrolytes shear modulus and are thus not consistent with the MonroeâNewman model for âdendrites.â The observations suggest that Li-plating in pre-existing ïŹaws produces crack-tip stresses which drive crack propagation, and an electroch-emomechanical model of plating-induced Li inïŹltration is proposed. Lithium short-circuits through solid electrolytes occurs through a fundamentally different process than through liquid electrolytes. The onset of Li inïŹltration depends on solid-state electrolyte surface morphology, in particular the defect size and density