▎ 摘　　要

Herein, nitrogen, oxygen codoped porous carbon nanofibers (CNFs) from corn residue-derived lignin are fabricated via the electrospinning method, followed by introduction of graphenes (GNs) via a simple "brush-coating and drying" process. The obtained GN-coated carbon nanofibers (CNFs@GNs) exhibit a 3D network architecture, abundance of heteroatoms, excellent electrical conductivity, high specific surface area (700.92 m(2 )g(-1)), thus boosting the electrochemical performances. The CNFs@GNs electrode delivers a higher specific capacitance of 271.1 F g(-1) than CNFs (200.3 F g(-1)) at 1 A g(-1). Furthermore, the assembled CNFs@GNs symmetric supercapacitor exhibits an energy density of 20.3 Wh kg(-1) at the power density of 199.97 W kg(-1) together with a high charge/discharge reversibility of 97.3% and Coulombic efficiency of 99.81% after 10 000 cycles. This "brush-coating and drying" strategy utilized here provides a convenient and efficient route for designing CNFs and GN composites and can be utilized in other active materials.