Functionalization of supercapacitors electrodes oriented hydrochar from cornstalk: A new vision via biomass fraction

The development of corn stalk-based carbon materials presents a promising approach towards sustainable energy storage and agricultural waste valorization. However, the impact of varying portions of the cornstalk on electrochemical performance has been previously disregarded. An innovative strategy is proposed herein for the preparation of supercapacitor electrodes from different fractions of the same corn stalks via hydrothermal carbonization and KOH activation. The potential of the resulting composition, morphology structure, and electrochemical performance was analyzed to evaluate its suitability for supercapacitor electrodes. The capacity of CC-carbons could reach up to 133.32 F g-1 at 1 A g-1 and exhibit excellent electrochemical properties owing to their highly specific surface area (812.84 m2 g-1) in combination with their abundant active sites. Moreover, the leaf blade (LB) was found unsuitable for preparing porous carbon. The results further revealed that the high lignin content increased the material's defects and active sites. Additionally, inorganic components present in raw materials may remain in the activated carbons in the form of ash through mineralization reactions, thereby affecting pore formation and charge ion transport. The outcomes of this study provide a novel perspective on the high-value utilization of corn stalks.