Co 2+ -coordination-assisted enhancement of mechanical and iodynamic properties of 3D graphene-based double network hydrogels for all-solid-state supercapacitors

This paper reports an enhanced strategy for improving the mechanical flexibility and ionic kinetic properties of a double network hydrogel based on Co 2+ -coordination assistance. The modified double-network hydrogel was obtained by using acrylic acid and N , N -dimethylacrylamide as monomers, adding cross-linking agents and 3D nitrogen-doped graphenes. The tensile fracture rate of the modified hydrogel was 1925% and its tensile strength was 1696 kPa. In addition, the hydrogel exhibited excellent ionic dynamics, and its application to an all-solid-state supercapacitor was able to achieve a specific capacitance of up to 182.8 F g −1 . The supercapacitor exhibited an energy density of 34.2 Wh kg −1 , even when operating at a power density of 5 kW kg −1 , highlighting its significant potential for practical applications.