Enhancing the Volumetric Performance of Supercapacitors via Reconfiguration of Multiscale Structure of Commercial Activated Carbon by Mechanical Force

Activated carbon (AC) is a pivotal electrode material for supercapacitors owing to its high specific surface area and mature manufacturing processes. However, traditional AC electrodes suffer from a trade-off effect between porous structure and material density, impeding the achievement of volumetric energy density. Herein, a mechanical grinding post-treatment strategy is employed to reconstruct the full-scale pore network of commercial AC by simultaneously optimizing particle aggregation morphology and eliminating ineffective pores. Results demonstrate that prolonged mechanical treatment induces an evolution of carbon particles, characterized by initial fragmentation followed by aggregation, which significantly alters the macroscopic pore network. Comprehensive pore characterizations reveal that micropores and meso-/macropores can be synchronously adjusted during short-duration mechanical processing. With extended treatment, a dynamic transformation between closed and open pores occurs, enhancing the connectivity of the pore structure. Benefiting from this optimized configuration, the resulting carbon exhibits an ultra-low specific surface area of 17.7 m² g⁻¹ while delivering an excellent volumetric capacitance of 421 F cm⁻³. Furthermore, the constructed ionic liquid-based symmetric supercapacitor achieves an ultra-high volumetric energy density of 75.6 Wh L⁻¹. This work decouples the restrictive relationship between pore configuration and structural densification, and elucidates the impact of mechanical force on pore reconstruction.