• • NFPP-U0.5% delivers 80.3 mAh g−1 at 20 C, enabling high-power sodium-ion battery operation with minimal capacity fade under fast discharge conditions.
• • Capacity retention of 82.66% after 25,000 cycles at 20 C demonstrates exceptional long-term cycling stability, surpassing typical polyanion cathodes and reducing replacement costs in grid-scale storage.
• • The C–S–Fe interaction induces small lattice volume changes during cycling, as confirmed by in-situ XRD, mitigating mechanical degradation and extending electrode lifespan.
• • S-doped carbon coating with porous coral-like morphology enhances electronic conductivity and Na+ diffusion, addressing the intrinsic limitations of NFPP and enabling practical high-rate performance.