Conductive copper-based metal-organic framework nanowire arrays grown on graphene fibers for flexible all-solid-state supercapacitors

Abstract Graphene fiber-based electrodes have the promising potential to develop flexible supercapacitors because of their outstanding advantages such as small volume, lightweight, high mechanical flexibility and large-scale production. However, the low electrochemical performance severely blocks their practical application. In this study, integrating the conductive Cu3(2,3,6,7,10,11-hexahydroxytriphenylene)2 (Cu-MOF) nanowire arrays into the reduced graphene oxide (rGO) fibers significantly boosts the electrochemical performance. Inside the electrode structure, the 3D conductive Cu-MOF nanowire array layers with an open porous structure and large surface area significantly enlarge the contact area between electrode materials and electrolytes, shorten the electrolyte diffusion path and offer high electrical conductivity. This composite fiber electrode shows high capacitance property of 44.6 mF cm−2 at a scan rate of 5 mV s−1, good cycling stability and excellent mechanical flexibility. The assembled all-solid-state symmetric fiber supercapacitor exhibits an energy density of 0.51 μW h cm−2 at a power density of 2.54 μW cm−2. The promising electrochemical performance makes the rGO/Cu-MOF fiber electrode have a great future in the flexible supercapacitor field.