Carboxylic multiwalled carbon nanotube aerogel-based macroscale fiber as a highly porous current collector

Carbon nanotube yarn is a potential substance for the fabrication of fiber-shaped energy storage devices owing to its lightweight, stiffness, and excellent electrical properties. However, it has a compact structure with a limited pore volume, leading to insufficient active material loading and inadequate gel electrolyte penetration. These seriously restrict its application in fiber-shaped energy storage devices made entirely of solid-state components. Herein, glycerol-functionalized polyacrylonitrile nanofibers (GPN) are electro-spun and collected on Ti wire. And they are chosen as hydrophilic support to load carboxylic multiwalled carbon nanotubes (CMWCNTs) via dipcoating. After oxidation, a 3D rolled O-CMWCNTs@GPN/Ti aerogel fiber-shaped structure with macroscopic thickness and excellent stability in water is fabricated. The O-CMWCNTs@GPN/Ti structure has a high lengthspecific capacitance value of 15.2 mF cm-1 itself. It also can be used as a current collector to load pseudocapacitive materials to improve capacity. With polyaniline (PANI) electrodeposited in this structure, the asprepared hybrid aerogel electrode PANI@O-CMWCNTs@GPN/Ti displays a high specific capacitance of 52.6 mF cm-1 in a fiber-shaped supercapacitor device. All features suggest that O-CMWCNTs@GPN/Ti aerogel is an excellent candidate for flexible fiber-shaped energy storage devices.