Hierarchical Nanoporous Carbon with Thermally Tunable Microstructures for Electrochemical Supercapacitors

Decoupling the structural factors that govern capacitive charge storage in porous carbons remains challenging because pore accessibility, surface state, and local atomic order are often intrinsically intertwined. Here, a hierarchical nanoporous carbon is produced by sequential dealloying and thermally tuned into a correlated series of carbon frameworks with progressively modified microstructures. The as-prepared carbon features a bicontinuous meso-/microporous architecture, but is initially electrochemically inactive because of undesired surface species. Thermal treatment activates the carbon surface and continuously transforms the carbon walls from a highly disordered amorphous state to increasingly ordered graphitic structures, while largely preserving the micropore size distribution. Comparative analyses reveal that, after electronic activation, capacitance is governed jointly by accessible surface area and the intrinsic capacitance efficiency of the carbon surface, the latter being strongly dependent on the local atomic structure of the carbon walls. The hierarchical and highly disordered nanoporous carbon delivers the best overall supercapacitor performance, while thinner electrodes further improve high-rate utilization and also show competitive behavior in organic electrolyte. These findings establish a design principle for porous carbon supercapacitors based on balancing electrical activation, accessible microporosity, local structural disorder, and transport length, while highlighting dealloying-derived hierarchical carbons as a versatile platform for disentangling structure–property relationships in electrochemical energy storage.