Electrochemical Characterization of Single-Walled Carbon Nanotube Electrodes

Carbon nanotubes are of significant interest due to their unique properties and potential applications.1-4 We are interested in using single-walled carbon nanotubes (SWNTs) as an electrode material suitable for electromechanical actuators.5 Such application requires a good understanding of the electrochemical properties of SWNTs. In this initial report, we describe some of the basic electrochemi-cal characteristics of sheets of SWNTs. These sheets, called nanotube paper (NTP) due to their appearance, consist of SWNT bundles joined by mechanical entanglement and van der Waals interactions. The NTP shows high porosity and large surface area.5,6 It is general-ly considered1-6 that in the material used the nanotubes ends are closed and that the interstitial spaces between individual nanotubes inside a bundle are not accessible to the electrolyte. Consequently, the pores responsible for most of the surface area correspond to the void spaces between bundles. The techniques utilized for the characteriza-