All-Climate and Nonflammable Electrolyte with a Strong Anion–Solvent Interaction for High-Performance Lithium Metal Batteries

Reinforced security and temperature tolerance are key prerequisites for the practical application of lithium metal batteries (LMBs). Achieving an optimal balance between maintaining a stable interface at a high temperature and ensuring rapid ion transport under a low temperature remains a critical challenge. Herein, an all-climate nonflammable electrolyte comprised of triethyl phosphate (TEP), lithium bis((trifluoromethyl)sulfonyl) azide (LiTFSI), and lithium nitrate (LiNO3) is proposed. The strong interaction between NO3– and TEP broadens the melting point of the electrolyte to −91.5 °C. A well-regulated lithium-ion solvation structure with low desolvation energy contributes to the formation of a durable inorganic–organic hybrid solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI), thereby enhancing the interfacial compatibility significantly. Consequently, the LMBs with the optimized TEP-based electrolyte demonstrate remarkable electrochemical performance in a wide temperature range of −60∼100 °C. The valuable insights gained from this work can offer theoretical guidance for developing wide-temperature electrolytes and high-performance LMBs.