Multiple Strategies to Build High-Performance Spherical Na-Ion Layered Oxide Cathodes

The development prospect of layered transition metal oxides in sodium-ion batteries is excellent, but there are some problems, such as poor cycle stability and a complex phase transition. The spherical NaNi_0.25Fe_0.15Mn_0.3Ti_0.1Sn_0.05Co_0.05Li_0.1O₂ (SP-HEO) has been developed to address the challenges faced by O3-type layered oxide in sodium-ion batteries. The SP-HEO material is synthesized by piling and high entropy. The multiple strategies combine to enhance the electrochemical performance and air stability. The SP-HEO demonstrated a specific discharge capacity of 150.1 mA h g^-1 at 0.1 C and 100.4 mA h g^-1 at 7 C. Ex situ XRD analysis confirmed that the SP-HEO effectively retards complex phase transitions. This study not only introduces a high-entropy design for high tap density spherical storage materials but also dispels industry concerns regarding the performance of sodium ion layered oxide cathode materials.