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Synthesis & Electrochemical Characterization of Homogeneous & Heterogeneous Composite Nanotube & Nanowire Arrays

Principal Investigator(s): 

Abstract: 

Lee’s group is investigating fundamental electrochemical properties of conductive polymer nanotubes and their heterogeneous and homogeneous metal oxide nanocomposite structures. Conductive polymer nanotubes are electrochemically synthesized in a porous alumina membrane, and their structures are characterized using electron microscopes. Various electrochemical techniques such as cyclic voltammetry, galvanostatic cycles, and AC impedance spectroscopy are used to characterize electrochemical properties (capacitance, power, energy) of the nanotubes. Metal oxides/conductive polymer nanocomposite structures are also synthesized and characterized. We show that PEDOT nanotube-based supercapacitor can achieve high power density of 25 kW/kg while maintaining 80 % of their energy density (5.6 Wh/kg). This high power capability is attributed to their fast charge/discharge of nanotubular structures: hollow nanotubes allow electrolyte ions to readily penetrate into the polymer and access their internal surfaces, while thin wall provides short diffusion distance to facilitate the ion transport. The significance of this work is on

  1. the demonstration of high-power based on nanotube and nanowire structures as well as the characterization of their detailed structures and evaluation of their electrochemical performance and
  2. the provision of a plausible mechanism to explain the fast charge/discharge in the nanostructures.

supercapacitors
(a) Supercapacitors made of PEDOT nanotubes in porous alumina template.
(b) Schematic of ion transport (doping or charging) in a single nanotube.
Complete and fast doping of anions can be achieved because of short
diffusion distance and high porosity in the PEDOT nanotubes.