Perspectives on Li Dendrite Penetration in Li7La3Zr2O12‐Based Solid‐State Electrolytes and Batteries: Materials, Interfaces, and Charge Transfer

Abstract Garnet‐type Li 7 La 3 Zr 2 O 12 (LLZO) solid‐state electrolytes have gained significant attention as one of the most promising electrolyte candidates for high‐energy‐density energy storage devices due to their superior stability and high ionic conductivity. However, the problem of lithium (Li) dendrite penetration into LLZO hinders the practical application of LLZO in solid‐state Li metal batteries (SSLMBs). Multidisciplinary evaluations are carried out to understand the mechanism of dendrite penetration. Herein, the formation and evolution of different types of Li dendrites within LLZO are reviewed. The Li dendrite penetration process is addressed from the perspectives of material design, Li/LLZO interfacial adaptability, and the interfacial charge transfer process. On this basis, recent efforts and solutions to inhibiting the penetration of Li dendrites in LLZO, including stabilizing LLZO phase and densification techniques, interfacial modifications, and grain boundary manipulations, are summarized. It is expected that the in‐depth understanding of the Li dendrite penetration and corresponding solutions will provide a systemic guideline toward the development of LLZO‐based solid‐state electrolytes and the commercialization of ultra‐stable SSLMBs.