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 _0.25 Fe _0.15 Mn _0.3 Ti _0.1 Sn _0.05 Co _0.05 Li _0.1 O ₂ (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.