Pre-nitrogen Doping Effects on Mesoporous Activated Carbon Derived from Passifloraedulis for High-Performance Supercapacitors

Biomass-derived activated carbon is a promising active material for energy storage in electrical double-layer capacitors (EDLCs) owing to its superior electrical conductivity, tunable chemical bonding, and low cost. However, the significant degradation of electrical conductivity by the increase in oxygen functional groups and decrease in graphitization during the biomass-activation process limits the application of high-performance supercapacitors. Maintaining electrical conductivity while increasing the specific surface area remains a major challenge. In this study, a high-performance supercapacitor electrode material is fabricated by promoting the pore-generation reaction during KOH activation through an appropriate amount of pre-N doping with Passiflora edulis, which provides a high surface area, electrical conductivity, and ion accessibility at the electrode–electrolyte interface. Although the semi-carbonized precursors undergo the same KOH activation process, the final pore structure and chemical-bonding state change depending on the inherent biochemical structure and nitrogen functionalization. Therefore, we present the characteristics of the precursor and directional potential of the process to obtain the characteristics (pore distribution, electrical conductivity, and wettability) required for supercapacitors using different fruit parts with different chemical compositions in the same derived carbon precursors.