• A novel N, B co-doped sodium alginate-based porous carbon (NBSPC) was synthesized via one-step co-carbonization, exhibiting enhanced pore structure and surface functional groups.
• The NBSPC cathode delivers an excellent rate performance of 85.4 mA h g−1 at an ultra-high current density of 40 A g−1 in zinc-ion hybrid capacitors.
• Outstanding cycling stability is achieved with 94.5% capacity retention after 15,000 cycles at 20 A g−1, demonstrating durability for practical applications.
• The N, B co-doping strategy provides a template-free, cost-effective approach to develop high-performance carbon cathodes for advanced energy storage.