Electrochemical charge storage properties of vertically aligned carbon nanotube films: Effects of thermal oxidation

Vertically aligned carbon nanotube (VACNT) films were synthesized and investigated in vitro for their potential use as a neural stimulation electrode. Materials and electrochemical (EC) characterization (cyclic voltammetry, electrochemical impedance spectroscopy, and high-rate potential transient measurements) were performed before and after flash oxidation in O 2 at various temperatures and over a wide frequency range. The results showed distinct EC behavior within three ranges of treatment temperature. Oxidative thermal treatments that did not visibly etch the VACNT film caused a significant improvement in electrode performance compared to the as-deposited electrode. Surprisingly, flash oxidation within a narrow temperature range (400 < T ≥ 450 °C) selectively increased capacitance/charge injection at high frequencies (10 2-10 4 Hz). A phenomenological model is proposed to explain the temperature-dependent behavior and indicates the importance of modifying a porous coating to increase the charging rate rather than maximizing the total charge accumulated at long times for high-rate charge storage applications. © 2012 American Chemical Society.

Full Text

Duke Authors

Cited Authors

  • Brown, B; Parker, CB; Stoner, BR; Grill, WM; Glass, JT

Published Date

  • 2012

Published In

Volume / Issue

  • 116 / 36

Start / End Page

  • 19526 - 19534

International Standard Serial Number (ISSN)

  • 1932-7447

Digital Object Identifier (DOI)

  • 10.1021/jp304419a

Citation Source

  • SciVal