Electrochemical performance of flexible graphene-based fibers as electrodes for wearable supercapacitors

The miniaturized supercapacitors are promising energy storage devices that can replace traditional batteries in portable electronics. Excellent graphene-based fibers have becoming a dominant role as electrode materials for supercapacitors. Unique and excellent carbon nanotubes and graphene composite fibers (G/CNTs) with outstanding mechanical properties and excellent capacitive behaviors were prepared by a facile, one-step and timesaving process. Scanning electron microscopy images displayed that the diameter of obtained G/CNTs was similar to 150 mu m, and showed a directional structure of graphene nanosheets and few-walled carbon nanotubes (FWNTs) along the specific direction of the as-prepared composite fibers. The electrochemical performances of the resultant fibers as flexible electrodes were estimated by a three-electrode system. The as-synthesized G/CNTs delivered a specific volumetric capacitance of 312.6 F g(-1) at the current density of 200 mA g(-1), and the capacitance of Gio/CNTs could still remain at 89.6% of original capacitance after 10,000 cycles. Furthermore, the flexible G/CNTs could be fabricated into a stretchable and compressible fiber spring. The fiber super capacitor displayed much efficient electrochemical capacitive behaviors, promising for being portable and wearable electronics, and this development can potentially promote its application in other fields.