Localized Solvent‐Anchored Carboxylate Ester Electrolyte Enables Wide Temperature and Fast Charging Sodium Metal Batteries

ABSTRACT Sodium‐metal batteries (SMBs) have attracted considerable interest due to their abundant raw material supply and high energy density. Nevertheless, realizing fast charging and long‐term cycling stability over a wide temperature range remains a considerable challenge. In this work, we propose a novel strategy that integrates molecular anchoring with weak solvation by modulating the dipole‐dipole interactions between methyl propionate (MP) and fluoroethylene carbonate (FEC). This approach effectively stabilizes the free solvent ratio, suppresses the irregular dendrite formation under low‐temperature and fast‐charging conditions, and minimizes HF generation at elevated temperatures, thereby enhancing electrolyte chemical stability and Na + desolvation kinetics. These synergistic enhancements enable rapid Na + transport and facilitate the formation of a robust interface layer across a broad temperature range. Consequently, Na 3 V 2 (PO 4 ) 3 ||Na cells demonstrate stable operation from −40°C to 70°C and sustain over 10 000 cycles at 80°C, outperforming previous reports on wide‐temperature fast‐charging systems. Notably, the cells achieve a capacity retention of 98.58% after 1200 cycles at −20°C and 85.93% after 1500 cycles at 60°C. Moreover, pouch cells configured with this electrolyte exhibit superior all‐weather adaptability and fast‐charging capability. This work offers valuable insights for developing high‐performance SMBs operable under broad‐ temperature conditions.