Hydrogen-bond-guided micellar self-assembly-directed carbon superstructures for high-energy and ultralong-life zinc-ion hybrid capacitors

Abstract

Well-intricate carbon superstructures have tremendous potential as cathode materials in zinc-ion hybrid capacitors (ZHCs) owing to their maximum accessible surface, superior structural integrity and robustness. However, significant challenges still remain in simplifying the synthesis process. Herein, a hydrogen-bond-guided micellar self-assembly strategy was leveraged to construct flower-like carbon superstructures for targeting high-energy and ultralong-life ZHCs. This approach employed aggregated micelles to serve as structural guides facilitating the controlled growth of oligomers into intricate polymer superstructures with a distinct flower-like morphology and architecture. The subsequent hierarchical porous carbon superstructures exhibited a considerable surface area (2824 m² g⁻¹) with efficient charge-transport pathways. Remarkably, the synergistic combination of dual-ion storage, ion-accessible pore structures, and endogenous zincophilic sites enabled exceptional performance. This included a remarkable energy density of 160.8 W h kg⁻¹ at 112.1 W kg⁻¹, extraordinary cycling stability of 200 000 cycles at 20 A g⁻¹, and a high specific capacity of 262.8 mA h g⁻¹ at 0.2 A g⁻¹. The exceptional electrochemical performances were primarily attributed to the effective and alternating Zn²⁺/CF₃SO₃⁻ adsorption at the abundant, easily accessible zincophilic sites within the superstructures. Additionally, proton-assisted zinc-ion storage through H⁺ adsorption onto the carbon matrix significantly enhanced the capacity and rate performance. This work paves a novel pathway for the exploration and design of well-intricate carbon superstructure cathodes for enabling superior performance in ZHCs.