Three-Dimensional Porous Carbon Nanotubes/Reduced Graphene Oxide Fiber from Rapid Phase Separation for High-Rate All-Solid-State Supercapacitor.

Graphene fiber-based supercapacitors are rising as one of the greatest potentials for portable/ wearable energy-storage devices. However, their rate performance is not well-pleasing, which greatly impedes their broad practical applications. Herein, 3D porous CNT/rGO fibers were prepared by a non-solvent induced rapid phase separation method followed by hydrazine vapor reduction. Benefit from their three-dimensional porous structure, large specific surface area and high conductivity, the fabricated supercapacitor exhibits a high volume capacitance of 54.9 F cm-3 , and a high energy and power density (4.9 mWh cm-3 and 15.5 W cm-3 ). Remarkably, the supercapacitor works well at a high scan rate of 50 V s-1 and shows a fast frequency response with a short time constant of 78 ms. Furthermore, the fiber-shaped supercapacitor also exhibits very stable electrochemical performances when it is subjected to mechanical bending and succeeding straightening process, indicating its great potential application in flexible electronic devices.