Nitrogen‐Doped Carbon‐Coated Na ₂ FeTi(PO ₄ ) ₃ with Enhanced Sodium Storage Performance

The practical application of NASICON‐structured phosphate cathodes in sodium‐ion batteries (SIBs) is primarily constrained by their inherently low electronic conductivity and unsatisfactory cycling durability, despite their advantageous three‐dimensional ion diffusion pathways. To address this challenge, a nitrogen‐doped carbon‐coated Na ₂ FeTi(PO ₄ ) ₃ composite was developed through a facile sol–gel route using dicyandiamide (DCDA) as a nitrogen/carbon precursor. Through systematic optimization of the DCDA content, we tailored the NFTP@NC‐2 composite to achieve an outstanding initial discharge capacity of 123.1 mA h g ⁻¹ at a current density of 20 mA g ⁻¹ . More importantly, it exhibits exceptional high‐rate performance (100.0 mA h g ⁻¹ at 1000 mA g ⁻¹ ) and outstanding long‐term cyclability, retaining 89.1% capacity retention after 1000 cycles. These improvements are ascribed to the DCDA‐induced elevation in carbon layer graphitization, which promotes better electron transport and Na ⁺ diffusion kinetics, thereby lowering interfacial resistance. The results highlight the potential of the NFTP@NC‐2 composite as a high‐performance cathode material for advanced sodium‐ion storage systems.