• FeNi bimetallic doped carbon coating on NaTi2(PO4)3 significantly enhances electronic conductivity and Na+ migration, improving rate capability and cycling stability.
• The NTP–C–FeNi composite delivers a high reversible capacity of 116.75 mAh·g−1 at 0.1 A·g−1, retaining 95.9% of initial capacity, and maintains 85.3% capacity retention after 500 cycles at 1.5 A·g−1.
• The synergistic effect of FeNi doping and carbon coating widens Na+ transport pathways and accelerates insertion/extraction, addressing the intrinsic poor conductivity of NTP.
• The findings demonstrate the potential of bimetallic doped carbon-modified NTP as a promising anode material for practical aqueous sodium-ion batteries.