Accelerating Electrochemical Kinetics in Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 Cathodes Through Oxygen Vacancy Modulation for Wide‐Temperature Ah‐Level Sodium‐Ion Batteries

at 10C and retains 96.42% capacity after 1500 cycles at 2C. Moreover, kilogram-scale synthesis using cost-effective raw precursors has been achieved via a sand-milling-assisted spray-drying route. When assembled into Ah-level pouch cells with hard carbon anodes, the NFPP-2.79-based cell demonstrates excellent rate capability (93.75% capacity retention from 0.5C to 4C), outstanding cyclability (75.63% retention after 3000 cycles), and superior safety under extreme conditions (overheating, crushing, nail penetration, overcharge, and external short-circuit). This work highlights oxygen vacancy modulation as an effective pathway for advancing polyanionic cathodes toward practical applications.