A Scalable and Low‐Temperature Route to Abundant Heteroatoms‐Doped Freestanding Carbon Anodes for Fast Sodium‐Ion Storage Kinetics

ABSTRACT Realizing fast‐charging sodium‐ion batteries with outstanding power density is a key challenge for next‐generation flexible electronics. At present, carbon‐based anodes are considered the most promising commercial candidates yet remain limited rate performance. To improve the sluggish kinetics of conventional carbon anodes, herein we introduce an ideal electrode architecture that combines structural engineering with chemical modulation, incorporating hierarchical pore structures and heteroatom sites into carbon nanofibers, establishing a continuous conductive network, and stabilizing heteroatom chemistry, thereby redistributing capacity toward fast, reversible, surface‐dominated sodium‐ion storage. This deliberately designed structure provides abundant sodium storage sites and rapid electron/ion transport pathways, reduces the tendency toward Na‐plating, suppresses side reactions, and mitigates structural stress during cycling. Consequently, the anode delivers a high reversible specific capacity (414 mAh g −1 ), an excellent rate performance (134 mAh g −1 at 10 A g −1 ), and a high initial Coulombic efficiency (83.90%). This study offers an effective strategy for achieving high‐rate, long‐life, and mechanically robust sodium‐ion storage devices, paving the way for next‐generation flexible electronics.