Dual-metallic site regulation boosts charge storage in zinc-ion hybrid supercapacitors

Zinc-ion hybrid supercapacitors (ZIHCs) are compelling candidates for next-generation energy storage owing to their intrinsic safety, low cost, and high power density. However, their practical implementation remains hindered by the limited energy density of traditional carbon-based cathodes. Here, we rationally design porous carbon nanofibers embedded with atomically dispersed Zn and Fe dual-metal sites (ZnFe/PCNFs), synthesized via electrospinning followed by controlled carbonization. The introduction of Fe modulates the local electronic structure of Zn centers, thereby facilitating enhanced d -orbital hybridization and stronger ion adsorption through the formation of ZnFeN 6 coordination motifs. Coupled with high surface area and hierarchical porosity, these atomic-level interactions facilitate exceptional ion accessibility and rapid charge-transfer kinetics. As a cathode for ZIHCs, ZnFe/PCNFs deliver a specific capacity of 213 mAh g -1 , exceptional high-rate capability, and long-term cycling stability over 20000 cycles. This work elucidates mechanisms of dual-metal atomic coordination and provides a robust design strategy for high-performance, durable aqueous energy storage systems. Porous carbon nanofibers embedded with atomically dispersed Zn and Fe bimetallic sites (ZnFe/PCNFs) are developed for high-performance zinc-ion hybrid supercapacitors. The unique ZnFeN 6 configuration, combined with high specific surface area, porous architecture, and heteroatom functionalities, facilitates efficient ion adsorption and charge transfer, delivering outstanding electrochemical performance. • ZnFeN6 in ZnFe/PCNFs boosts Zn2+/anion adsorption and charge kinetics. • Hierarchical porous structure of ZnFe/PCNFs enables ultrafast ion diffusion. • In ZnFe/PCNFs, Fe regulates Zn’s electronic structure to enhance ion storage.