• Journal Article

Electrochemical Charge Storage Properties of Vertically Aligned Carbon Nanotube Films: Effects of Thermal Oxidation

Citation

Brown, B., Parker, C. B., Stoner, B., Grill, W. M., & Glass, J. T. (2012). Electrochemical Charge Storage Properties of Vertically Aligned Carbon Nanotube Films: Effects of Thermal Oxidation. Journal of Physical Chemistry C, 116(36), 19526-19534. DOI: 10.1021/jp304419a

Abstract

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 degrees 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