Effects of zirconia coating on improvement of sodium-ion migration in NaNi1/3Fe1/3Mn1/3O2 cathodes for sodium-ion batteries

To investigate the mechanism by which ZrO 2 modification affects the electrochemical performance of the NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NFM) cathode material for sodium-ion batteries, ZrO 2 -coated NFM (ZrO 2 @NFM) was prepared via high-temperature calcination. XRD refinement results revealed that ZrO 2 modification increased the Na-layer spacing in the NFM material. XPS analysis results demonstrated that ZrO 2 modification adjusted the Mn 3+ /Mn 4+ ratio in NFM by reducing the Mn 3+ content. Electrochemical test results revealed that, compared to NFM, ZrO 2 @NFM exhibited superior rate capability and cycling stability. It also exhibited significantly enhanced Na + diffusion coefficients and reduced interfacial charge transfer resistance. The ZrO 2 coating increased Na-layer spacing, reduced electrochemical polarization, and inhibited side reactions. In summary, the synergistic effect of component regulation and surface engineering through ZrO 2 coating improved Na + diffusion kinetics and enhanced cycling stability.