The Effects of Parameters for Preparing Conducting Polymer and Modification of Carbon Nanotubes on Electrochemical Characteristics of Aluminum Capacitors

Abstract

Carbon nanotubes (CNTs) which are directly grown on nanoporous alumina templates by chemical vapor deposition are modified by acid-treatment or/and annealing and then a negative electrode is obtained. Next, alumina is deposited onto the nanoporous alumina templates with the grown as well as modified CNTs by a chemical liquid phase deposition method and then a positive electrode is obtained. Finally, the negative electrode coated with solid electrolyte polymerized by changing weight ratios between iron(III) p-toluenesulfonate hexahydrate-6 H 2 O and 3,4-ethylenedioxythiophene is assembled with the positive electrode into an aluminum capacitor. The capacitance of the aluminum capacitor reaches a maximum at 6 of the weight ratio between iron(III) p-toluenesulfonate hexahydrate-6 H 2 O and 3,4-ethylenedioxythiophene. Furthermore, the highest capacitance as well as operation potential of the aluminum capacitor and the lowest leakage current density of the aluminum capacitor at the 10000th cycle of potential cycling are obtained by the CNTs being treated with acid and annealed. Moreover, the decreasing rates of the capacitance as well as operation potential of the aluminum capacitor and the increasing rate of the leakage current density of the aluminum capacitor for the raw CNTs are quicker than those for the CNTs treated with acid or/and annealed.