Stabilizing P3‐Type Oxides as Cathodes for High‐Rate and Long‐Life Sodium Ion Batteries by Disordered Distribution of Transition Metals

Abstract As potential cathodes for sodium ion batteries, layered Na x TMO 2 (0.44 ≤ x ≤ 1, TM = transition metal) materials show high specific capacities but poor cycling and rate performance. In layered Na x TMO 2 , the distribution of TM at crystal sites determines the electrostatic interaction between TM and the coordinated atoms and affects the electrochemical behavior. Herein, the cycling performance of P3‐type Na 0.67 Mn 0.67 Ni 0.33 O 2 materials with ordered and disordered arrangement of TMs is investigated at different rates. Unlike the TM‐ordered material, the disordered one can be cycled at 2000 mA g −1 for 1500 cycles with 89% capacity retention. X‐ray absorption spectroscopy is performed to elucidate the reason for long cycle life of the TM‐disordered P3‐type Na 0.67 Mn 0.67 Ni 0.33 O 2 from the sight of local structural changes around Mn and Ni. The experimental results show that the structural stability of NiO 6 units in the TM‐disordered material is responsible for its better cycling performance in comparison with that of the TM‐ordered material.