Modulation of hierarchical porosity in metal-doping graphene/carbon hybrid aerogels for capacitive energy storage

Carbon aerogels hold great promise as the electrode materials for energy storage owing to their desirable porous structures and specific surface areas. Here, we report a scalable approach for the preparation of Co-doped graphene/carbon hybrid aerogel (CGCA) with hierarchically porous structure through a dual cross-linking strategy. By adjusting the cross-linking structure of the hydrogel precursor, the porous structure of CGCA can be readily regulated and the specific surface area of CGCA can achieve 1217 m 2 g −1 . As a result, the CGCA samples not only manifest improved electrical conductivity, but also possess enhanced capacitance storage capacity. The optimized CGCA electrode displays a high specific capacitance of 371 F g −1 at 1 A g −1 and maintains a large specific capacitance of 57 % at 150 A g −1 . Meanwhile, the supercapacitor assembled with CGCA electrodes shows a high specific capacitance of 80 F g −1 at 0.5 A g −1 and good cyclic stability with a capacitance retention of 95 % after 10,000 cycles. Moreover, the supercapacitor device can provide a high energy density of 11.1 Wh kg −1 at a power density of 250 W kg −1 . The superior energy-storage behaviors of CGCA make them promising electrode materials for high-performance supercapacitors. Benefited from the dual cross-linking effect from cobalt ions and graphene oxides, the cobalt-doped graphene/carbon hybrid aerogel (CGCA) exhibits desirable hierarchical porosity and thereby enhanced capacitive energy storage than the graphene/carbon aerogel (GCA) and pure carbon aerogel (PCA). • A facile strategy to construct the metal-doped graphene/carbon hybrid aerogels (CGCA) is reported. • The dual cross-linking effects from metal ions and graphene oxide can regulate the pore structures of CGCA. • The CGCA electrodes exhibit high capacitance of 371 F g -1 at 1 A g -1 , with good rate performance and cycle stability. • The supercapacitors with CGCA electrodes can achieve a high energy density of 11 Wh kg -1 at a power density of 250 W kg -1 .