Solid-state nuclear magnetic resonance for garnet-type based solid lithium electrolytes

Solid-state batteries show high safety and theoretical energy density, receiving rapid-growing attention in both academic investigations and industrial applications. The garnet-type based solid electrolytes (Garnet-SEs) play a vital role due to their high Li+ conductivity and high electrochemical stability. The atomic structure at local environments, such as the Li+ coordination and site of doped ions, will have important impact on the ability of transport and migration pathway that determine ion conductivity and electrochemical performances. In addition to the average structure from long range perspective, the understanding at atomic level will be crucial for developing strategies to enhance ionic conductivity in Garnet-SEs. Solid-state nuclear magnetic resonance (NMR) is a powerful tool that can probe the local atomic environments and dynamics on a molecular level. NMR is proven as a suitable technique for characterizing the light weight and small radius of Li element, which is challenge for some conventional methods. In this review, atomic structure, ion pathways, dynamic and microstructure formation of Garnet-SEs from NMR view were discussed. These insights obtained from various NMR techniques will provide essential information for informing the control development and optimization of Garnet-SEs, contributing to the advancement of high-performance, safe, and reliable solid-state batteries.