A Polysulfides‐Defensive, Dendrite‐Suppressed, and Flame‐Retardant Separator with Lean Electrolyte for Room Temperature Sodium–Sulfur Batteries

Abstract The dissolution/shuttling of sodium polysulfides, coupled with sodium dendrites growth, severely compromises the lifespan and stability of room temperature sodium–sulfur (RT Na–S) batteries. Herein, it proposes employing a functionalized porous ZIF‐based membrane (PZM) to address these two challenges. First, the metal ions embedded within the zeolitic imidazolate framework chemically bind with polysulfide anions, curtailing their detrimental shuttling. Second, the tailored porous structure of the membrane ensures a selective and uniform pathway for sodium ions, significantly reducing non‐uniform deposition and curbing dendritic sodium growth. Third, the intrinsically non‐combustible nature of the ZIF‐based membrane acts as a fortification against thermal outbursts and electrolyte decomposition. Implementing this polysulfide‐resistant, dendrite‐inhibiting and flame‐retardant PZM with a standard S/C cathode leads to the creation of a robust separator with lean electrolyte RT Na–S battery. This configuration may impart a novel perspective for the advancement and enhancement of RT Na–S battery systems.