Porz, Lukas ; Swamy, Tushar ; Sheldon, Brain W. ; Rettenwander, Daniel ; Frömling, Till ; Thaman, Henry L. ; Berendts, Stefan ; Uecker, R. ; Carter, W. Craig ; Chiang, Yet-Ming (2017)
Mechanism of Lithium Metal Penetration through Inorganic Solid Electrolytes.
In: Advanced Energy Materials, 7
doi: 10.1002/aenm.201701003
Article, Bibliographie

Abstract

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 β-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/infiltrates at defects, but only above a critical current density. Eventually, infiltration 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 Monroe–Newman model for “dendrites.” The observations suggest that Li-plating in pre-existing flaws produces crack-tip stresses which drive crack propagation, and an electroch-emomechanical model of plating-induced Li infiltration is proposed. Lithium short-circuits through solid electrolytes occurs through a fundamentally different process than through liquid electrolytes. The onset of Li infiltration depends on solid-state electrolyte surface morphology, in particular the defect size and density.

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