LLZO-Based Solid-State Lithium Metal Batteries: Electrolyte Regulation and Interface Optimization Strategies

Solid-state lithium-metal batteries (SSLMBs) are regarded as a next-generation electrochemical energy storage technology due to their potential for high energy density and enhanced safety. As a critical component, solid-state electrolytes (SSEs) significantly influence the performance of SSLMBs. Among various SE types, garnet-type Li₇La₃Zr₂O₁₂ (LLZO) electrolytes exhibit notable chemical stability against lithium metal, thereby attracting considerable attention. However, LLZO-based SSLMBs are still plagued by short-circuit failures caused by lithium dendrites. This review elucidates the origins of the issues related to SSEs, focusing on inherent imperfections such as high porosity and electron leakage at grain boundaries, as well as challenges at the interface between the SSEs and the lithium metal anode, including poor solid contact. Additionally, we summarize current strategies and recent research advances addressing lithium dendrite formation in garnet-type SSLMBs, aiming to support future development and technological breakthroughs in this energy storage technology.