Advanced Carbon‐Fluorine Interfacial Engineering on Current Collectors for Room Temperature Sodium‐Sulfur Batteries

Abstract Room temperature sodium‐sulfur (RT Na‐S) batteries are promising for large‐scale energy storage due to their high theoretical energy density and cost‐effectiveness. However, challenges such as unstable sodium deposition/dissolution hinder their practical application. This study addresses this issue by introducing an advanced carbon‐fluorine interfacial on an aluminum current collector (CF@Al) via a pyrolytic evaporation‐deposition method. The fluorine‐rich interface promotes the formation of NaF‐rich solid electrolyte interphase (SEI) and improves electrolyte wettability, while the continuous carbon network ensures efficient electron/ion transport and alleviates electric field‐induced inhomogeneities. The intrinsic flexibility of the carbon‐fluorine interface effectively buffers the volume variations during cycling. Consequently, the CF@Al architecture enables a high sodium plating/stripping Coulombic efficiency of 99.6% at 0.5 mA cm −2 and stable cycling for over 1000 h. When integrated into full RT Na‐S cells with a standard sulfur/carbon cathode without a catalyst, the CF@Al/Na anode enables a high initial reversible capacity and superior long‐term cycling performance with minimal capacity decay. This work highlights the great potential of advanced current collectors in enabling high‐performance RT Na‐S batteries through efficient interfacial behavior regulation.