Recent advances in anodic interface engineering for solid-state lithium-metal batteries

Lithium (Li) metal is recognized as “Holy Grail” in energy storage field because of its high specific capacity and ultralow anodic potential. To realize the high-safety and high-energy-density rechargeable batteries, the marriage of Li metal and high-safety solid-state electrolytes (SSEs) may be a promising and irreplaceable choice. In this case, various advanced Li-contained and Li-free cathodes, such as LiNi0.8Co0.1Mn0.1O2 (NCM811), S and O2, can be adopted to further improve the energy density of solid-state Li-metal batteries (SSLMBs). However, regardless of the complex interface problems between different cathodes and SSEs, the poor anodic interface between Li metal and SSEs has become the critical obstacle of the commercial application of SSLMBs, mainly including i) poor interfacial contact and dendrite growth, ii) chemical/electrochemical instability and iii) chemo-mechanical expansion. In this review, we analyze aforementioned anodic interface problems in SSLMBs. Based on these, advanced strategies to ameliorate the anodic interface by surface modification, interfacial structural design within SSEs and Li metal, composition optimization of SSEs and Li metal, and external methods such as pressure control and high temperature are systematically discussed. In situ characterization technologies are also introduced to understand the dynamic evolution of anodic interface. Moreover, we outline future perspectives in anodic interface engineering for SSLMBs.