Electrochemical behavior and capacitance properties of carbon xerogel/multiwalled carbon nanotubes composites

Abstract

The electrochemical behavior of carbon xerogel/multiwalled carbon nanotubes composite in a 6 M KOH solution has been investigated. Three different mixtures of teflonized carbons with varying nanotube content were prepared. The electrodes containing multiwalled carbon nanotubes were found to provide enhanced capacities compared to those prepared with only carbon xerogel. Cyclic voltammetry and charge-discharge experiments reveal the presence of a strong resistive component, which decreases as the amount of nanotubes increases. Electrochemical impedance spectroscopy results analyzed in terms of an adequate physicochemical model of the porous electrode, show that an increasing amount of nanotubes enhances both the effective solid phase conductivity and the effective liquid phase conductivity, linked to the porosity of the electrodes.