Enhancement of zinc-ion storage capability by synergistic effects on dual-ion adsorption in hierarchical porous carbon for high-performance aqueous zinc-ion hybrid capacitors

Aqueous zinc -ion capacitors (AZICs) are considered potential energy storage devices thanks to their ultrahigh power density, high safety, and extended cycling life. Carbon -based materials widely used as cathodes in AZICs face challenges, such as inappropriate pore sizes, poor electrolyte - electrode wettability, and insufficient vacancy defects and active sites. These limitations hinder efficient energy storage capacity and long-term stability. To address these issues, the B and F co -doped hierarchical porous carbon cathode materials (BFPC) are constructed through a facile annealing treatment process. The BFPC-2//Zn device exhibited high capacities of 222.4 and 118.3 mAh g -1 at current densities of 0.2 and 10 A g -1 , respectively. Notably, the BFPC-2//Zn device demonstrated long-term cycling stability with a high capacity retention of 96.9 % after 20,000 cycles at 10 A g -1 . Additionally, the assembled BFPC-2 based AZICs displayed a maximum energy density of 175.8 Wh kg - 1 and an ultrahigh power density of 17.3 kW kg -1 . Mechanism studies revealed that the exceptional energy storage ability and charge -transfer process of the BFPC cathode are attributed to the synergistic effect of B and F heteroatoms and the coupling effect between vacancy defects and pore size. This work presents a novel design strategy by incorporating B and F active sites into hierarchical porous carbon materials, providing enhanced energy storage capabilities for practical application in AZICs.