Mechanical failure of garnet electrolytes during Li electrodeposition observed by in-operando microscopy

• Published in: Journal of power sources 2019-02, Vol.412, p.287-293
• Main Authors: Manalastas, William, Rikarte, Jokin, Chater, Richard J., Brugge, Rowena, Aguadero, Ainara, Buannic, Lucienne, Llordés, Anna, Aguesse, Frederic, Kilner, John
• Format: Article
• Language: English
• Subjects: All-solid-state batteries; Ceramic electrolyte; Failure mechanisms; Garnet; Li electrodeposition/plating; Short-circuit; Soft dendrites
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2018.11.041

Metallic Li anodes are key to reaching high energy densities in next-generation solid-state batteries, however, major problems are the non-uniform deposition of Li at the interface and the penetrative power of Li metal during operation, which cause failure of the ceramic electrolyte, internal short-circuits and a premature end of battery life. In this work, we explore the anode-electrolyte interface instability of a Li metal-garnet electrolyte system during Li electrodeposition, and its implications for mechanical fracture, Li metal propagation, and electrolyte failure. The degradation mechanism was followed step-by-step during in-operando electrochemical cycling using optical and scanning electron microscopy. High amounts of Li electrodeposition in a localized zone of the interface lead to ceramic fracture followed by an electrode-to-electrode electrical connection via a conductor Li metal filament. This work enables deeper understanding of battery failure modes in all-solid-state batteries containing a ceramic electrolyte membrane. [Display omitted] •In-operando visualization of Li metal propagation in a ceramic electrolyte.•Mechanisms of mechanical failure in a garnet electrolyte.•Li electrodeposition leading to short circuit via soft dendrite formation.•Limitation of all-solid-state batteries with a ceramic membrane.