Corn stem-derived, hierarchically nanoporous carbon as electrode material for supercapacitors

Waste biomass-derived, carbon-based materials have potential as electrode materials for energy storage because of their advantageous characteristics, which include their low cost, sustainability, eco-friendly recycling, and intrinsic microstructures. In this study, corn stem-derived, hierarchically nanoporous carbon (CS-HNPC) was fabricated by carbonization of corn stems, followed by activation with potassium hydroxide. The CS-HNPC had a high specific surface area of ~1,420 m² g⁻¹ and abundant nanopores with a hierarchical pore structure, which allowed the facile diffusion of electrolyte ions. It also showed a high specific capacitance of 232 F g⁻¹ and good rate capabilities in an aqueous electrolyte when used as an electrode material for a supercapacitor. In addition, it exhibited stable cycling over 10,000 charge/discharge cycles at a current density of 10 A g⁻¹.