Sustainable Release of LiNO₃ from a Fluorine‐Decorated Metal–Organic Framework Separator to Enable High‐Performance Li‐Metal Batteries in Carbonate Electrolytes

Abstract High‐voltage Li‐metal batteries hold great prospects for boosting energy density, while the Li‐metal anodes show poor compatibility with high‐voltage tolerant carbonate electrolytes, leading to unstable solid‐electrolyte interphase (SEI) and uncontrolled Li dendrites growth. Herein, a F‐decorated UIO‐66/polyimide (PI) functional separator encapsulated with LiNO 3 (LNO@UIO‐66F/PI) is rationally designed to regulate the interfacial chemistry and Li deposition behavior. Specifically, the UIO‐66F nanoparticles in situ grown on the PI fibers form continuous electronegative nanochannels, which promote rapid and uniform Li + flux while repelling the anion migration. Furthermore, the LiNO 3 encapsulated in the UIO‐66F nanopores sustainably releases to form a thin and conductive Li 3 N‐rich SEI. This synergy effect induces a dense and spherical Li deposition behavior, effectively inhibiting the growth of Li dendrites. Consequently, this LNO@UIO‐66F/PI separator demonstrates highly reversible Li plating/stripping over 1000 h at an extremely high current density of 10 mA cm −2 in carbonate electrolytes, and also enables the stable cycling of Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 cell over 1000 cycles under a high cut‐off voltage of 4.5 V, paving the way for practical application of high‐energy‐density Li‐metal batteries.