Review of Garnet-Based Solid Electrolytes for Li-Ion Batteries (LIBs)

The scientific community is exploring novel all-solid-state batteries (ASSBs) as a substitute for conventional lithium-ion batteries with liquid electrolytes. These ASSBs possess several attractive advantages, including improved safety, extended temperature range, and improved energy density. Solid-state electrolytes (SSE) have become significant parts of ASSBs. For example, garnet-type Li7La3Zr2O12 (LLZO) SSE has shown promise among the various forms of SSEs. LLZO demonstrates ionic conductivity of 10(-3) to 10(-4) S/cm and remarkable chemical durability in combination with lithium metal. Because of these qualities, LLZO is a good option for solid-state Li-metal batteries. Various advancements have been made in garnet-type SSEs and ASSBs since the discovery of LLZO in 2007, resulting in enhanced electrochemical durability and energy density. The advantages of LLZO include durability and safety under elevated temperatures, high-temperature stability, and safety of garnet-type electrolytes. This review article examines current developments in garnet-type LLZO electrolytes, considering experimental research and theoretical findings. We discuss the synthetic methodology, modifications, the robustness of these garnet-based electrolyte materials, novel blueprints for nanostructures, understanding of the electrolyte decomposition pathway, and routes to overcome the electrolyte decomposition pathway with regard to LZZO. Additionally, battery architectures and integrations are explored. The review provides a comprehensive outlook for garnet-based LLZO electrolyte research, focusing on its applications in different solid-state battery concepts, such as Li-ion, Li-S, and Li-air batteries. It highlights the opportunities and perspectives that garnet-type LLZO electrolytes offer, serving as a roadmap for future advancements in SSEs and batteries.