In situ nanoarchitecturing of conjugated polyamide network-derived carbon cathodes toward high energy-power Zn-ion capacitors

Abstract

Zn-ion hybrid capacitors, with a large-capacity Zn anode (battery-type) integrated with a capacitive cathode, hold great potential to relieve the unsatisfactory energy-to-power ratio of aqueous supercapacitors. The research into cathode design is expected to bridge the capacity gap between the two electrodes without sacrificing the inherent power/cycling superiorities but is still in its infancy. In this work, robust O/N-decorated porous carbon cathodes were derived by the in situ calcination of conjugated polyamides, wherein the solvent-guided strategy was applied to shape the carbon nanoarchitecture for the activation of Zn storage sites. After optimizing the solvent–precursor interactions, the packed particle architecture (C_DMF) ultimately exposed ample electrosorption platform up to 1656 m² g⁻¹, and O/N dopants (15.77 wt%) promoted interfacial Zn adsorption by lowering the energy barrier for C–O–Zn bonding. Further experimental evaluations revealed that the CO species on the robust C_DMF framework tended to boost reversible chemical adsorption to form C–O–Zn bondings while maintaining durable charge transfer, which minimized capacity loss even at high rates. As a result, the aqueous C_DMF//Zn capacitor achieved a large capacity of 180 mA h g⁻¹, an ultrahigh energy density of 106.7 W h kg⁻¹ and an excellent power output of 13.4 kW kg⁻¹, as well as 91.1% capacity retention over 300 000 cycles. This design strategy gives an appealing insight into the subtle fabrication of high-performance carbon cathodes and highlights their applicability towards practical Zn-based energy storage in the future.