Sodium-ion batteries have attracted significant interest due to the abundance of sodium resources and their cost-effectiveness. However, their practical use is often limited by the low capacity and poor cycling stability of current cathode materials. Developing high-performance cathodes with increased capacity and strong cyclic stability remains a key research challenge. In this study, we introduce a surface engineering method involving Nb 2 O 5 coating to improve the electrochemical performance of Na 3 VFe(PO 4 ) 3 -based cathodes. Three different coating levels (1%, 3%, and 5%) were applied using an affordable, scalable wet-chemical synthesis process. Compared to uncoated samples, the 1%-coated ones showed significantly better capacity retention at high current rates and demonstrated excellent stability in both half-cell (93% after 700 cycles at 5C) and full-cell (89% after 200 cycles at 2C) setups. The enhanced performance of the coated materials results from a combination of high surface capacitance, improved ion diffusion kinetics, and lowered internal resistance. These results suggest that Nb 2 O 5 -coated Na 3 VFe(PO 4 ) 3 has strong potential as a next-generation cathode material for sodium-ion batteries. • Niobium oxide coating enhances sodium iron vanadium phosphate cathodes. • Excellent high-rate capacity retention and stability in half- and full-cells. • Coating improves capacitance and diffusivity and lowers internal resistance. • Wet-chemical coating is low-cost, scalable, and suitable for mass production.
Morais et al. (Thu,) studied this question.