O3-NaNi0.47Zn0.03Mn0.5O2 cathode material for durable Na-ion batteries

Abstract O3-type transition metal oxides as the cathodes for Na-ion batteries have attracted extensive attention owing to their high theoretical specific capacity and ease of synthesis. This work indicates enhanced electrochemical reversibility and improved air stability via a rational Zn2+ doping for O3-NaNi0.5Mn0.5O2. It exhibits a discharge capacity of 113 mAh g−1 at 0.5 C, excellent capacity retention of 80% after 150 cycles, and the capability to release a capacity of 82 mAh g−1 at 5 C in the voltage range of 2–4 V. The doped cathode undergoes a phase transition of O3-O3/O′3-P3-P′3-O''3 with a small volume change of approximately 2.00% in the voltage range of 2–4 V, and a subsequent slight structural change in the high voltage range of 4–4.2 V, which well demonstrates the enhanced cyclic stability. The assembled full cell confirms the feasibility of applying O3-type NaNi0.47Zn0.03Mn0.5O2 cathode for Na-ion batteries. Thus, the work suggests an efficient strategy to better release the potential of high-energy cathode for Na-ion batteries.