Hierarchical porous carbon derived from Monoon longifolium seeds as high-performance supercapacitor electrodes

Electrochemical capacitors predominantly rely on porous carbon materials with high specific surface areas; however, precise control over pore size distribution remains a critical challenge in optimizing electrode performance. In this study, we present a two-step activation strategy for fabricating hierarchical porous carbon derived from Monoon longifolium seed biomass (HPC-MS), which enables systematic tuning of the pore architecture. The optimized carbon material demonstrated a high specific surface area of 898 m² g⁻¹ with well-developed hierarchical porosity. When evaluated in a two-electrode symmetric configuration, the HPC-MS electrode delivered an impressive specific capacitance of 368 F g⁻¹ at a current density of 1 A g⁻¹, along with outstanding cycling stability, retaining 97.2% of its capacitance after 5000 charge–discharge cycles. These results demonstrate the potential of waste biomass as a sustainable carbon source and provide a promising pathway for developing high-performance supercapacitors through rational pore structure engineering.