Ultrahigh Surface Area Hierarchically Porous Carbon Materials from Polyacrylamide–Cellulose Hydrogel for High-Performance Supercapacitors

High surface area, hierarchically micro/mesoporous carbon materials with interconnected pore structures have significant potential as electrode materials for high-performance supercapacitor applications. Here, we present the synthesis of ultrahigh surface area hierarchically porous carbon materials, prepared by potassium carbonate (K 2 CO 3 ) activation of polyacrylamide–hydroxy propyl cellulose (PAM–HPC) hydrogel at high temperatures (500–900 °C), and their energy storage performances in two- and three-electrode cell setup. The carbon material obtained by carbonization of the PAM–HPC hydrogel at 800 °C exhibits an ultrahigh surface area of 3387.2 m 2 g –1 with a large pore volume of 1.963 cm 3 g –1 . The electrode prepared using this material demonstrated excellent supercapacitance performance in the three-electrode system, achieving a high specific capacitance of 545.5 F g –1 at 1 A g –1 current density with superior rate capability and an outstanding cycling stability of 96.3% after 5000 charge–discharge cycles. Furthermore, the assembled symmetric supercapacitor device constructed by using this material showed a high specific capacitance of 102.5 F g –1 at 0.5 A g –1 . It delivers a high energy density of 17.2 W h kg –1 at the power density of 550 W kg –1, and a superior cycling stability of 94.2% after 5000 consecutive charge–discharge cycles. The electrochemical properties reported here indicate that hierarchically porous carbons obtained from PAM–HPC hydrogels are promising materials for high-performance supercapacitor applications.