Dimethylsulfamoyl Fluoride‐Based Electrolyte With Dual Cathodic‐Anodic Stability for Sodium‐Ion and Sodium‐Metal Batteries

ABSTRACT Sodium‐based batteries are attractive low‐cost alternatives to lithium‐ion systems; however, their practical deployment is limited by the insufficient electrochemical stability of conventional electrolytes. Here, we introduce a high‐performance electrolyte comprising sodium bis(fluorosulfonyl)imide (NaFSI) dissolved in N,N ‐dimethylsulfamoyl fluoride (DMSF), a fluorosulfonamide solvent. DMSF is synthesized via a sulfur fluoride exchange (SuFEx) click reaction under ambient conditions. Compared with conventional ether‐based electrolytes, the NaFSI/DMSF delivers improved electrochemical performance derived from its enhanced reductive and oxidative stabilities, affording higher coulombic efficiency and superior cycling stability for both sodium metal and hard carbon anodes, along with stable capacity retention of high‐voltage NaNi 0.6 Fe 0.2 Mn 0.2 O 2 cathodes. Comprehensive physi…