Three-Dimensional Graphene-Wrapped CoSe2 Nanowires for High-Performance Asymmetric Supercapacitors

Herein, a three-dimensional graphene (3DG)-coated porous nanowire architecture was developed, which exhibited favorable multiscale and multidimensional porous nanostructures, resulting in an airgel (3DG/CoSe2NWs) with abundant ion transport channels, high specific surface area, and excellent electrical conductivity. This airgel can be used directly as a flexible binder-free electrode with a high specific capacity of 1272 F g–1 at 1 A g–1 and an excellent rate capability of 1156 F g–1 when the current density was increased to 10 A g–1. The prepared asymmetric supercapacitor (3DG/CoSe2NWs//AC) exhibited excellent cycle stability with a coulombic efficiency of 96.19% at 5 A g–1 after 10,000 cycles. The performance of the flexible asymmetric supercapacitor (ASC) device under different bending angles was evaluated, and the discharge stability was confirmed, which indicated its potential in practical applications. Furthermore, two 3DG/CoSe2NWs//AC ASCs (1 cm × 3 cm) connected in series were able to light up an LED lamp, highlighting the promising prospect of the device.