Recent advances of Li₇La₃Zr₂O₁₂-based solid-state lithium batteries towards high energy density

To satisfy the demand for high energy density and high safety lithium batteries, garnet-based all-solid-state lithium batteries (ASSLBs) are the research hot spots in recent decades. Within the garnet family, Li₇La₃Zr₂O₁₂ (LLZO) is a promising candidate for solid-state electrolytes (SSEs) that has been extensively investigated due to the high ionic conductivity, chemical stability, electrochemical stability, air stability, thermal stability and safety. Recently, several laboratory-scale works on LLZO-based ASSLBs are achieved. However, although LLZO-based SSEs have made tremendous advancements today, there are still several critical issues in the practical application of ASSLBs with high energy density and low cost. Herein, optimization of LLZO structure, preparation of high-quality LLZO-based SSEs, engineering of the interface between LLZO-based SSEs and realization of LLZO-based ASSLBs with high energy density are systematically analyzed, discussed, and summarized to offer a clearer comprehension of the crucial challenges and future research orientations. It is expected to not only enhance the knowledge of audiences in this field but also facilitate the achievement of practical commercial applications in LLZO-based ASSLBs.