Nitrile‐Assisted Hybrid‐Solvation Electrolyte Enables Wide‐Temperature, High‐Voltage, and Ultrafast‐Charging Lithium‐Metal Batteries

The stable operation of lithium metal batteries (LMBs) requires simultaneous stabilization of anode and cathode interfaces, a challenge that intensifies under extreme operating conditions due to divergent formation mechanisms. Here, we present a hybrid‐solvation electrolyte design employing isobutyronitrile (IBN) as the primary solvent to regulate both Li + solvation and interfacial protection. Functioning as a bifunctional modulator, IBN drives dual‐source interfacial chemistry at the anode where anion‐enriched solvation and coordinated‐solvent decomposition co‐generate an inorganic‐ and nitrogen‐rich solid–electrolyte interphase (SEI) while lowering Li + desolvation barriers. At the cathode surface, excess IBN molecules form an adsorption‐derived protective layer that effectively suppresses solvent oxidation and stabilizes the cathode–electrolyte interface (CEI) under high‐voltage and high‐temperature conditions. Enabled by this design, Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 coin cells exhibit robust operation across wide temperatures (−40°C∼60°C) and high voltages (4.6 V), alongside ultrafast charging capabilities (20 C). Upscaling to practical pouch cells under lean‐electrolyte conditions (1.2 g Ah −1 ) yields a high energy density of 403 Wh kg −1 with a 12‐min fast‐charging/discharging capability. The hybrid solvation design framework integrates solvent‐ and anion‐driven chemistries in a unified electrolyte, enabling high‐energy LMB operation under demanding conditions.