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.