Abstract
To describe charge conduction in conducting polymers a dual transmission line with one resistance describing electronic motion in the polymer and a second resistance describing ionic motion in the pores has proved applicable to a number of systems. A further feature of ac impedance plots for these polymers is a high-frequency semicircle. This may be attributed to a charge-transfer resistance and double-layer capacitance at either the electrode/polymer or the polymer/electrolyte interface. A general expression for such a charge-transfer resistance is derived and it is shown that the current will be proportional to the difference in Nernst potential across such a resistance. This circuit element together with a double-layer capacity is then combined with the dual transmission line. A general expression for the ac impedance for the combined circuit is obtained. Care has to be taken to use the right potentials, Nernst, Donnan or the actual potential. Depending on the relative resistances in the transmission line different types of behaviour can be found. In particular the variation of the real part of the impedance at high frequency can be used to determine whether the charge-transfer resistance is at the electrode or at the electrolyte interface. The procedure is exemplified with results from polypyrrole.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of the Chemical Society, Faraday Transactions
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.