Conductive Poly(vinyl alcohol)/Multi-Walled Carbon Nanotube Nanocomposite Fiber Electrodes for Lightweight and Energy Dense Supercapacitor Applications

Danielle A. Lynch, Hunter T. Beauchamp, Jeffrey Tantow, Sawyer J. Madsen, Evan W. Ousley, Blake T. Koppel, Enoch A. Nagelli

Department of Chemistry & Life Science, Chemical Engineering Program, United States Military Academy, West Point, New York 10996

Abstract

This study develops an energy-free, scalable, and cost-effective method for synthesizing conductive PVA/CNT nanocomposite fibers and films for configurable, lightweight, and high-performance electrodes for supercapacitor applications. CNTs are comprised of carbon atoms in hexagonal formations with a backbone of alternating carbon-carbon double bonds (C=C) that form linear high aspect ratio walled tubes. Chemically oxidized CNTs have carboxylic acid, carbonyl, and epoxide functional groups on the side walls and tips of the carbon hexagons along the CNT structure. In this method, multi-walled carbon nanotubes (CNTs) were chemically oxidized in strong acids at high temperature, PVA was hydrolyzed and integrated with the oxidized carbon nanotubes, and the resulting PVA/ox-CNT mixture was extruded and dehydrated in a bath of methanol to form nanocomposite PVA/CNT fibers and films through hydrogen bonding and physical crosslinking. The Fourier-transform infrared (FTIR) spectra was confirmed the chemical functional groups difference between pristine CNTs from ox-CNTs. Raman spectroscopy of the chemically functionalized CNTs indicates the presence of oxygen in the carbon nanotube crystalline structure by the increase in the ratio of D-band to G-band intensity. The scanning electron microscopy (SEM) was used to characterize the structure of the PVA/CNT nanocomposite and the nanocomposite network of integrated ox-CNTs into the PVA polymer. The electrochemical characterization of the PVA/CNT fiber was conducted with cyclic voltammetry (CV) of the CNT/PVA fiber in 0.5 M KCl at various scan rates (5 mV/s, 10 mV/s, 25 mV/s, 50 mV/s, 75 mV/s, and 100 mV/s) exhibiting capacitive double layer current from 0.2 V to +0.8 V (vs Ag/AgCl) demonstrating the fibers conductivity and exhibiting capacitive rectangular shape throughout the voltage window.

KEYWORDS: Nanocomposites, Polymers, Carbon Nanotubes, Films, Fibers, Supercapacitor Electrodes

CONTACT: Dr. Enoch A. Nagelli, Email: enoch.nagelli@westpoint.edu