Low‐LUMO Solvation Structure Enabled by Propylene Carbonate for Stable Lithium Metal Batteries at Low‐Temperature

ABSTRACT Propylene carbonate (PC) is a promising ethylene carbonate (EC) replacement for low‐temperature electrolytes due to its low melting point (−48.8°C). However, its tendency to form an unstable, organic‐rich solid electrolyte interphase (SEI) on Li anodes severely limits practical application. Multicomponent electrolyte show potential in constructing stable interfaces; however, the contribution of specific solvation structures in multicomponent electrolyte to the interface formation process remains unclear. Herein, a multicomponent electrolyte is designed by introducing LiBF ₄ / LiDFOB/ LiNO ₃ into methyl acetate (MA)/ PC/ fluoroethylene carbonate (FEC) mixed solvent. The PC with a low donor number (15.1) exhibits weak interactions with Li ⁺ , which not only facilitates rapid Li ⁺ desolvation but also allows more anions into the solvation shell to form anion‐rich solvation structures. More importantly, the lowest unoccupied molecular orbital (LUMO) energy is significantly lower when PC replaces EC in the solvation structure, which facilitates the formation of an inorganic‐rich SEI. The inorganic‐rich SEI possesses high mechanical strength, thereby suppressing Li dendrite growth. Consequently, the cell delivers an initial specific capacity of 145.7 mAh g ⁻¹ with 97.5% capacity retention after 180 cycles at −20°C. This work provides a strategy for advanced electrolyte design to realize practical low‐temperature LMBs.