Synergetic enhancement of structural stability and kinetics of P’2-type layered cathode for sodium-ion batteries via cation–anion co-doping

The P'2-type layered oxides attract much attention as viable cathode materials for sodium-ion batteries (SIBs), due to their high specific capacity and environmental friendliness. Nevertheless, the sluggish Na+ diffusion kinetics and drastic capacity decay triggered by irreversible phase transition limit their large-scale application. In this study, we employ a synergistic optimization strategy involving cation and anion dopants to successfully restrain intergranular strain and tune local electronic structure, strengthening structural stability and electrochemical performance of the cathode material. Specifically, the Mg2+ dopant suppresses Na+/vacancy rearrangement and Mn-O anisotropic changes, while the F− dopant facilitates Na+ transport and alleviates phase evolution in high-voltage regions. Through this co-doping design, the modified electrodes display more alleviated voltage decay and exceptional capacity retention enhancements ranging from 6.57 % to 81.23 % after 750 cycles at 1000 mA g–1. This work provides novel perspectives on precise design of cathode materials, making layered oxides promising contenders for the next generation energy storage systems.