High‐Entropy Co‐Free O3‐Type Layered Oxyfluoride: A Promising Air‐Stable Cathode for Sodium‐Ion Batteries

(2-4.3 V) is observed in the first few cycles, along with a significant improvement in stability during prolonged cycling. Furthermore, in situ and ex situ diffraction studies during charging/discharging reveal that the high-entropy strategy successfully suppresses the complex phase transition. The impressive outcomes of the present work strongly motivate the pursuit of the high-entropy approach to develop efficient cathodes for sodium-ion batteries.