Excellent Electrochemical Performance and Air Storage Stability of Na-Ion Layered Oxide Cathodes Benefiting from...

The widespread application of layered oxides is constrained by their low electrochemical performance and complex irreversible phase transition. The high entropy oxide NaNi_0.25Fe_0.15Mn_0.3Ti_0.1Sn_0.05Co_0.05Li_0.1O₂ (HEO) is synthesized by leveraging the entropy stabilization effect, which offers a partial solution to this issue, but electrochemical performance and air stability imperative to be improved. On the high entropy oxide HEO, due to the strong bond energy of Ce-O, the introduction of Ce⁴⁺ improves the specific discharge capacity and reduces the battery gas production problem. It also improves the air stability. NaNi_0.25Fe_0.15Mn_0.3Ti_0.1Sn_0.03Ce_0.02Co_0.05Li_0.1O₂ (HEO-Ce2) demonstrated a specific discharge capacity of 160 mA h g^-1 at 0.1 C. The discharge-specific capacity retention rate of the material is 86%, after air exposure for 10 days. The high entropy effect and introduction of Ce⁴⁺ provide a viewpoint for a layered oxide of sodium-ion batteries.