Depressed P3–O3′ phase transition in an O3-type layered cathode for advanced sodium-ion batteries

The introduction of Cu 2+ and Sn 4+ ensures the remarkable structure stability of O3-Na 0.993 Ni 0.382 Mn 0.428 Cu 0.098 Sn 0.049 O 2 to depress the Na + /vacancy rearrangement and P3 → O3′ phase transition, and hence good electrochemical performance.