Simultaneous Activation and Heteroatom Doping via Potassium Citrate in Chitosan‐Derived Porous Carbon for Supercapacitors

A novel strategy is developed to synthesize hierarchical porous carbon materials (CPC‐ x ) by employing potassium citrate as the activator and sulfonated precarbonized chitosan as the carbon precursor. The effects of the chitosan‐to‐potassium citrate mass ratio on the material structure and electrochemical properties are systematically investigated. The optimized sample, CPC‐4, exhibits remarkable electrochemical performance. It possesses a unique three‐dimensional hierarchical porous architecture with a high specific surface area of 1454.72 m 2 g −1 and substantial heteroatom doping (1.45 at% N, 9.84 at% O). Specifically, it achieves a high specific capacitance of 345 F g −1 at 0.5 A g −1 and outstanding cycling stability with 98.57% capacitance retention after 10,000 cycles at 10 A g −1 . When assembled into a symmetric supercapacitor, the CPC‐4//CPC‐4 device delivers attractive energy densities of 5.86 Wh kg −1 in 6 M KOH and 24.55Wh kg −1 in 1 M Na 2 SO 4 . These compelling results demonstrate the great promise of CPC‐4 as a high‐performance electrode material for advanced energy storage systems.