Spore-derived porous carbon with tailored heteroatom doping for anode of sodium-ion capacitors

• • The optimized GLSHC-HNO3 anode delivers an ultrahigh reversible capacity of 446.1 mAh g−1 at 50 mA g−1 and retains 237.3 mAh g−1 at 2 A g−1, demonstrating superior rate capability for high-power sodium-ion storage. • • The full sodium-ion capacitor achieves an energy density of 114.4 Wh kg−1 at 290 W kg−1 and 43.1 Wh kg−1 at 1450 W kg−1, with a maximum power density of 5800 W kg−1, outperforming many reported SICs. • • Long-term cycling stability is exceptional: 84.3% capacity retention after 5000 cycles at 2.0 A g−1 with nearly 100% Coulombic efficiency, indicating robust electrode durability for practical applications. • • The synthesis integrates hydrothermal pretreatment, low-temperature carbonization, and acid-mediated functionalization to create hierarchical porosity and multi-element co-doping, offering a scalable and sustainable route for biomass-derived carbon anodes.