Composite Films of Poly(3,4-ethylenedioxythiophene) and Metal Oxide or Polyoxometallate Redox Centers for Effective Charge Storage in Redox Capacitors

摘要

Conducting polymer based hybrid (composite) films have drawn considerable attention during recent years due to their potential utility in such different technologies as displays, smart windows, sensors, catalysis, as well as secondary batteries and redox capacitors. One of the frequent problems related to the application of conducting polymers is a relatively low capacity to store charge in such devices. Among the organic polymers, PEDOT, or poly(3,4-ethylenedioxythiophene), and its derivatives have been recognized as one of the most stable organic polymers currently available. On the other hand, the use of amorphous tungsten oxide as an electrode material for display devices is based on not only its electrochromic properties but also very rapid and reversible proton supported redox transitions. The details of electrochemical preparation method for the fabrication of hybrid tungsten oxide/PEDOT films on carbon electrode substrates will be provided. The resulting system is characterized by fast redox reactions, high effective diffusion coefficients for charge propagation and excellent stability (resistance to degradation during repetitive potential cycling). The composite material provides capacitor-like performance. A cooperative effect (synergy) is expected with respect to the faradaic and capacitive responses of metal oxide and conducting polymer components. The hybrid system seems to be promising for the application to the construction of high current density charge storage devices.