Recycling of garnet solid electrolytes with lithium-dendrite penetration by thermal healing

Solid-state lithium metal batteries (SSLMBs) have attracted a lot of interest owing to their high safety and high energy density potential. However, the growth of lithium dendrite in solid electrolytes still hinders practical applications of SSLMBs. In this study, we develop a simple heat treatment method for reviving and recycling garnet oxide electrolytes with Li dendrite penetration. Interestingly, the recovered garnet electrolyte exhibits higher relative density, enhanced ionic conductivity and improved critical current density compared with the pristine one. The thermal healing is due to the products of the reaction between dendritic Li metal and air that contribute to the further densification of garnet electrolytes during heat treatment. This work demonstrates a new way to recycle garnet electrolytes, which may further extend to other various solid electrolytes.

Automated summary

Solid-state lithium metal batteries (SSLMBs) have potential for high safety and energy density, but the growth of lithium dendrite in solid electrolytes limits their practical applications. This study develops a simple heat treatment method to revive and recycle garnet oxide electrolytes with Li dendrite penetration. The recovered garnet electrolyte shows higher relative density, enhanced ionic conductivity, and improved critical current density compared to the pristine one. Thermal healing is attributed to the reaction products between dendritic Li metal and air, contributing to further densification of garnet electrolytes during heat treatment.