Hybrid-entropy regulation to construct O3@P2 layered oxide cathodes with high rate and stability for sodium-ion batteries.

O3-type layered oxides stand as promising cathode candidates for sodium-ion batteries (SIBs) owing to their high specific capacity and facile synthesis, yet their practical deployment is hindered by inherent issues of structural instability upon cycling, sluggish kinetics, and air sensitivity. Herein, we constructed an O3@P2 layered oxide material using a hybrid-entropy regulation strategy to enhance the stability, rate performance, and air stability of SIB cathode materials. Based on the O3-NaNi0.4Mg0.05Cu0.05Mn0.3Ti0.2O2 substrate material, the growth of the epitaxial P2 layer was precisely controlled via the coprecipitation method, ultimately yielding O3@P2 cathode materials with varying compositions. With the protection of P2 crystal domains on the microscale surface during the (de)sodiation process, the mechanical stress of the primary O3 phase is alleviated, effectively preventing structural damage of the O3 phase and achieving excellent structural integrity. Furthermore, the designed O3@P2 cathode has a high reversible capacity (157.7 mAh g-1 at 0.1C) and excellent rate performance (78.3 mAh g-1 at 10C), verifying the synergistic effect of the O3 phase and P2 phase. Employing hybrid-entropy regulation to construct interfacial epitaxial growth layers enhances the stability of O3-type layered oxides and offers valuable insights for improving the rate performance of layered oxide cathodes.