Manipulating ion transfer and interface stability by a bulk interphase framework for stable lithium metal batteries

Lithium metal batteries (LMBs) have attracted widespread concern as the next-generation energy storage devices with high energy density. At the surface of lithium metal anodes (LMAs) toward electrolytes, lithium plating always competes with interfacial reactions. This makes interfacial reactions light shadow right behind lithium plating, leading to performance degradation. Herein, lithium plating is spatially decoupled from interfacial reactions by constructing a 3D solid electrolyte interphase framework (3D-SEIF) inside LMAs. Spontaneous while mild chemical reactions between lithium metal and lithium bisfluorosulfonimide/lithium nitrate form the robust 3D-SEIF, mainly consisting of LiF, Li${}_3$N, and LiN${}_x$O${}_y$. The built-in 3D-SEIF avoids electrolyte contact but enables the diffusion and reduction of Li${}^{+}$ ions in the bulk phase, thus isolating the plating sites and electrolyte contact interface. The 3D-SEIF facilitates large granular plating and the generation of thin, inorganic-rich SEI. When assembled with high-loading LiNi${}_{0.6}$Co${}_{0.2}$Mn${}_{0.2}$O${}_2$ cathode (3 mAh cm${}^{-2}$), the cells present capacity retention of 92.0% after 130 cycles with barren electrolyte (≈30 µL) at 0.5 C. The conception of 3D inner interphase allows breaking the coupling of interfacial reactions with electrochemical reactions, which is taken for granted in electrochemical consortium. It also desires to inspire new thoughts to develop scalable solutions for the early industrialization of LMBs. (© 2023 Wiley‐VCH GmbH)