Garnet-based solid-state Li batteries: From materials design to battery architecture

Driven by the demands for high energy density and safe Li batteries, designing a high-performance, all-solid-state Li battery (ASSLB) has been the focus of much attention in the past few decades. As a promising solid electrolyte (SE) candidate, the garnet family has been extensively studied, mainly due to its high ionic conductivity and stability toward reaction with elemental Li. Recently, several works have realized garnet-based ASSLBs at the lab scale. The aim of this Focus Review is to provide a brief description of the garnet structure, its optimization for ionic conductivity, and synthesis methods for bulk, thin-film, and composite garnet SEs, as well as a detailed comparison of garnet-based ASSLBs in terms of cell design and testing considerations. This work is targeted to provide a fundamental insight into the latest achievements in the field that can pave the way to realize practical garnet-based ASSLBs.