Unveiling the Electrochemical Versatility of N‐Doped Porous Carbon in Aqueous and Redox Additive Electrolytes

Supercapacitors are prized for their high‐power delivery, though their energy storage capacity is generally lower than that of batteries. A novel one‐pot strategy for synthesizing nitrogen‐doped porous carbon derived from KOH and urea‐activated wheat bread waste (Triticum aestivum) is presented. This unique synthesis simultaneously achieves chemical activation and nitrogen doping in a single‐step process, offering a cost‐effective and scalable route for high‐performance electrode materials. The supercapacitive properties of bread waste‐derived activated carbon (BWC‐700) in a 1 M H 2 SO 4 aqueous electrolyte are investigated, with 0.01 M hydroquinone (HQ) acting as a redox‐active agent. Morphological analysis via field‐emission scanning electron microscopy confirms the material's hierarchical porous structure. The (BWC‐700) exhibits a specific capacitance of 486 F g −1 at a current density of 1 A g −1 in a half‐cell configuration, with specific capacities of 1422 C g −1 and 904 C g −1 in three‐ and two‐electrode systems, respectively. When HQ is incorporated into the electrolyte, the AC demonstrates excellent cyclic stability, retaining 82% of its capacitance after 5000 cycles. Notably, BWC‐700 achieves a peak energy density of 56.5 Wh kg −1 , outperforming symmetric supercapacitors. These findings underscore the novel combination of waste valorization, green synthesis, and redox‐enhanced energy storage, making this work highly relevant and competitive in the rapidly evolving field of supercapacitors.