H360 Journal of The Electrochemical Society, 160 (6) H360-H367 (2013) 0013-4651/2013/160(6)/H360/8/$31.00 © The Electrochemical Society Electrochemical Characteristics of Closely Spaced Defect Tuned Carbon Nanotube Arrays

The ability to understand the role of defects in nanostructures, such as carbon nanotubes (CNTs), is crucial for determining their utility in many applications. We analyze the improvement in electrochemical performance of multi-walled CNT arrays that were exposed to argon and hydrogen based plasmas, where it was hypothesized that locally charged defects could be created through exposure to ions in the plasma. Such defects would influence the graphitic structure and were monitored through Raman spectroscopy. Cyclic voltammetry and associated electrochemical techniques were employed to infer the effects of plasma exposure on electrochemical charge transfer. It was seen that the effective area of charge transfer could be reproducibly increased through argon plasma exposure by ∼100%, while exposure to hydrogen based plasmas resulted in decrease in the effective area by nearly 60%, under the investigated conditions. Our experiments indicate enhanced faradaic currents, involving non-planar diffusion processes of the electroactive species, with implications for enhanced charge and energy storage. © 2013 The Electrochemical Society. [DOI: 10.1149/2.122306jes] All rights reserved. Manuscript submitted February 7, 2013; revised manuscript received April 2, 2013. Published April 10, 2013. The need for high energy density materials continually increases with the proliferation of portable electronics and energy harvesting de-vices. In this article, we present principles and methodologies, through which the energy density of electrochemical devices can be furthe