N–O Codoped Carbon Nanofibers Decorated with Graphene for High‐Performance Supercapacitors

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.