Synergistic Integration of Mesoporous Carbon and Dual Redox‐Active Electrolyte (NH ₄ VO ₃ /HQ) for High‐Energy Supercapacitors

The pursuit of advanced energy storage systems requires the development of novel electrode materials and electrolyte formulations. In this work, we report a synergistic strategy that integrates mesoporous carbon electrodes with a dual redox‐active electrolyte consisting of 0.05 M NH 4 VO 3 and hydroquinone (HQ) in 1 M Na 2 SO 4 aqueous solution. The mesoporous carbon, with a high surface area of 1300 m 2 g −1 and interconnected pore structure, facilitated efficient ion diffusion and charge storage. The introduction of dual redox species markedly boosted faradaic contributions, accounting for 60% of the total capacitance, as verified by Trasatti analysis. This hybrid system delivered a remarkable specific capacitance of 1380 F g −1 at 1 A g −1 . In a symmetric two‐electrode configuration, a maximum specific energy of 116.2 Wh kg −1 and a specific power of 852 W kg −1 were achieved—representing more than a 14‐fold improvement over pure electrolyte system. Moreover, 90% capacitance retention after 4000 cycles at 4 A g −1 confirmed the long‐term durability of the device. These findings demonstrate a powerful approach to overcoming the energy–power trade‐off in supercapacitors, highlighting the practical potential of mesoporous carbon combined with dual redox‐active electrolytes for next‐generation energy storage technologies.