Wheat straws-derived hierarchical porous carbon as electrode material for supercapacitor

Abstract Hierarchical porous carbon materials hold great potential in electrochemical energy storage, yet their efficient fabrication still faces numerous challenges. Herein, we successfully prepared hierarchical porous carbon materials with high specific surface area, broad pore size distribution, and interconnected pore structures by direct co-pyrolysis of wheat straw and potassium hydroxide, leveraging the natural reticular structure of wheat straw. As an electrode material for symmetric supercapacitors, CS-800 exhibited excellent electrochemical performance, retaining 96.94% of its initial capacity after 20,000 cycles at the current density of 1 A g⁻ 1 and achieving nearly 100% Coulombic efficiency. Furthermore, to expand its application scope, we assembled a zinc-ion capacitor using CS-800 as the cathode, which delivered a specific capacity of 173 mAh g⁻ 1 at a current density of 1 A g⁻ 1 . The hierarchical porous structure and interconnected channels significantly enhanced ion transport and storage capabilities and optimized the adsorption and desorption processes of charge carriers. This study demonstrates that the preparation of high-value-added electrode materials from biomass waste holds broad application prospects.