Achieving fast Zn-ion storage kinetics by confining nitrogen-enriched carbon nanofragments in a honeycomb-like matrix

Contriving ingenious and stable carbon structures is critical but of great challenge to improve the electrochemical kinetics in Zn-ion storage devices. In this study, nitrogen-enriched carbon nanofragments confined in a three-dimensional honeycomb-like hierarchical porous matrix are designed and constructed with a simple in situ confined thermal polymerization and carbonization strategy. By employing the as-prepared hierarchical carbon nanostructures for an advanced Zn-ion hybrid supercapacitor, a record high-rate capability has been obtained, manifested as a high specific capacity of 101.3 mAh g−1 at an extraordinary fast discharge rate of 100 A g−1. Additionally, a maximum energy density of 130.2 Wh kg−1 at a power density of 185 W kg−1, and a peerless power density of 92500 W kg−1 at the corresponding energy density of 93.7 Wh kg−1 are achieved, demonstrating the feasibility for high-power Zn-ion storage devices. Further kinetics and mechanism studies reveal that the fast Zn2+ storage kinetics originates from the N-enriched chemistry and the multiscale pore network which provide a hydrophilic surface, boost charge transfer, and expedite the ion diffusion.