Comprehensive Understanding of the Impact of Alkaline-Activated Bamboo-Derived Carbon for Enhancing Supercapacitor Performance

This study explored the potential of steam-treated bamboo-derived activated carbon (AC) for electric double-layer capacitor (EDLC) applications, using KOH, K₂CO₃, and Na₂CO₃ as activation agents to improve electrode materials. The activation process significantly affected the textural properties: KOH enhanced the surface area and micropore volume, K₂CO₃ impacted micropores and macropores, and Na₂CO₃ contributed to mesopores and macropores. TEM and SEM images showed distinct morphologies, with K₂CO₃ exhibiting bubble-like structures and Na₂CO₃ displaying a foam-like appearance. X-ray photoelectron spectroscopy analysis revealed specific surface modifications of ACs. Electrochemical performance assessments, including charge–discharge behavior, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS), demonstrated the superiority of KOH-AC in EDLC applications due to its high specific area and microporosity. The discharge capacitance of EDLC made from KOH-AC reached 24 F^g-1 at a current density of 100 mA^g-1, while those from K₂CO₃ and Na₂CO₃-AC did not surpass 14 F^g-1 under the same conditions. Fitting EIS data with the electrical circuit model partially revealed correlations between ion diffusion and capacitance values, although further durability studies are needed for practical applications. This investigation provides valuable insights into optimizing steam-treated bamboo-derived AC for advanced energy storage systems.