The role of interlayer chemistry in Li-metal growth through a garnet-type solid electrolyte
Journal
Advanced Energy Materials
Date
2020.02.12
Abstract
One of the critical issues that need to be addressed for the successful employment of solid electrolyte toward all-solid-state-batteries is to secure the chemical and physical stability of the interface among electrode material and solid electrolyte. Direct probe of those interfaces during the electrochemical reactions would significantly enrich our understanding and inspire potential solutions to regulate them. Herein, we attempt to elucidate the electrochemical nature of the interface between lithium metal and the garnet-type Li7La3Zr2O12 (LLZO) electrolyte by the real-time probing of the electrochemical lithium deposition through LLZO electrolyte in the anode-free solid-state battery setup. It is found that the lithium plating is strongly affected by the geometry of LLZO surface, where the non-uniform/filamentary lithium growth is triggered particularly at the morphological defects. More interestingly, we show that, when a surface of the LLZO is modified by an artificial interlayer, lithium growth behavior is significantly altered, and a regulated lithium deposition on the LLZO can be effectively achieved. The kinetics of lithium deposition process is remarkably varied depending on the nature of the interlayer species, subsequently leading to distinct lithium deposition morphologies. We believe our findings here broaden the understanding on the electrochemical lithium plating process at the interface between solid electrolyte and the lithium, and signify the role of the interlayer on tailoring the lithium deposition process. It further offers an insight on the lithium growth nature in the potential anode-free solid-state batteries.