▎ 摘　　要

In this paper, nitrogen-doped graphene hydrogel (NGH) has been synthesised by chemically reducing aqueous graphene oxide (GO) solution in the presence of carbamide.Its nitrogen content reaches 8.97 at%. It exhibits a 3D porous network structure with pore sizes of about 2 to 4 mu m comparable to the graphene hydrogel (GH) prepared without nitrogen source. Meanwhile, the NGH shows same hierarchical mesoporous structure with dominant pore size about 2-5 nm as the GH's. Besides, its specific surface area (132.8 m(2) g(-1)) is higher than that of the GH (122.9 m(2) g(-1)). The NGH can deliver an enhanced specific capacitance of 199.80 F g(-1) at 2 A g(-1) compared to that of the GH (142.23 F g(-1)). In addition, the NGH can retain 62.6% of specific capacitance from 2 to 50 A g(-1). The NGH also can maintain 97% of its initial specific capacitance after 20,000 cycles at 10 A g(-1).