Pore‐ and Heteroatom‐Controlled Superabsorbent‐Resin‐Derived Carbon Aerogels for Supercapacitors via Adjusting the Methylene Blue Concentration

Abstract The porous structure and heteroatom doping are crucial for the electrochemical performance of carbon materials for supercapacitors. However, designing carbon materials with appropriate pore sizes and heteroatom content is still facing daunting challenges. Herein, simultaneous regulation of porous structure and heteroatom doping in superabsorbent resin (SAR)‐based activated carbon aerogels (SACAs) is implemented by facilely immersing superabsorbent resin in methylene blue (MB) solution with different concentrations, and then followed by freeze‐drying and carbonization. The resulting SACAs possess variable oxygen/nitrogen/sulfur elements, adjustable high specific surface area, abundant micro–mesopores, and controllable porous structure. Hence, the assembled symmetric supercapacitors exhibit an excellent rate capacity of 83%, a superior energy density of 24.58 Wh kg −1 at the power density of 400 W kg −1 , as well as a satisfactory energy density of 20.84 Wh kg −1 at the power density of 4000 W kg −1 . Furthermore, outstanding cycling stability (94.59% retention) and high Coulombic efficiency (average value over 97%) are achieved for the supercapacitors after 10 000 cycles. This work broadens a new avenue to design the appropriate pore structure and heteroatom doping of carbon materials for high‐performance supercapacitors.