Electrochemical capacitive properties of CNT fibers spun from vertically aligned CNT arrays

Abstract

Due to their lightweight, large surface area; excellent electrical conductivity; and mechanical strength, carbon nanotube (CNT) fibers show great potentials in serving as both electrode materials and current collectors in supercapacitors. In this paper, the capacitive properties of both asspun CNT fibers and electrochemically activated CNT fibers have been investigated using cyclic voltammetry and electrochemical impedance spectroscopy. It is found that the as-spun CNT fibers exhibit a very low specific capacitance of 2.6 Fg −1 , but electrochemically activated CNT fibers show considerably improved specific capacitance. The electrochemical activation has been realized by cyclic scanning in a wide potential window. Different electrolytes have also been examined to validate the applicability of our carbon materials and the activation mechanism. It is believed that such an activation process can significantly improve the surface wetting of the CNT fibers by electrolyte (aqueous Na 2 SO 4 solution). The cycling stability and rate-dependence of the capacitance have been studied, and the results suggest practical applications of CNT fibers in electrochemical supercapacitors.

A Solid‐State Fibriform Supercapacitor Boosted by Host–Guest Hybridization between the Carbon Nanotube Scaffold and MXene Nanosheets

“…For comparison, devices comprised of bare CNT fibers and infiltrated MXene thin films were also tested in solid‐state using PVA‐LiCl gel electrolyte, respectively. Due to their highly packed/restacked structure, CNT fiber‐based and infiltrated MXene film‐based supercapacitors, respectively, exhibit capacitances of 0.6 and 1.2 F cm −3 at a current density of 1.0 A cm −3 (Figure S11, Supporting Information). By contrast, the C V of the MXene/CNT fiber‐based device was determined to be 22.7 F cm −3 at the current density of 0.1 A cm −3 .…”

Hybrid Fibers Made of Molybdenum Disulfide, Reduced Graphene Oxide, and Multi‐Walled Carbon Nanotubes for Solid‐State, Flexible, Asymmetric Supercapacitors

“…from vertically aligned MWCNT arrays are particularly desirable because of their excellent flexibility,m echanical strength, and electrical conductivity. [3] Although MWCNT fiber-based supercapacitors have been demonstrated, [4] the challenge to improve the energy density still remains.B ased on the equation E = 1 = 2 CV 2 ,w here E, C,a nd V are energy density,s pecific capacitance,a nd cell voltage,r espectively, E can be improved either by increasing the specific capacitance of the electrode materials or widening the operational voltage range. [5] In addition, the specific capacitance can be enhanced by the incorporation of electrochemically active nanomaterials (e.g., metal oxides or polymers) into MWCNT fibers.…”

Microfiber devices based on carbon materials

“…Fiber-shaped supercapacitors commonly use CF, CNTF or GF as electrodes and PVA-H 3 PO 4 (or PVA-H 2 SO 4 ) gel as the electrolyte [62][63][64][65][66][67][68]. A CF-based supercapacitor was fabricated by Zou's group (Fig.…”