Nonlinear Diffusion Behavior for the Prussian Blue Electrode: II. Interpretation of Variable Diffusivity during the Insertion/Extraction Processes
Resource
J. Electrochem. Soc.,149(2),E40-E44.
Journal
J. Electrochem. Soc
Journal Volume
149
Journal Issue
2
Pages
-
Date Issued
2002-02
Date
2002-02
Author(s)
Abstract
The apparent diffusivity has been measured at the Prussian blue (PB) electrode. It was shown that varies with the applied potential and there exists a minimum around the voltammetric peak potential. By applying the binary-solution model, which considers a partially reduced PB film as a binary mixture of PB and Everitt's salt (ES), the peak-shaped behavior was successfully explained. According to the model, the concave-up behavior is attributed to a corresponding concave-down excess energy-potential characteristic, which results in the maximum excess free energy and suppresses the random mixing of PB and ES. In addition, it is deduced that the coupled movement of and into a PB lattice or out of an ES lattice results in a net binary diffusion of PB and ES. To be sure, the binary-solution model provides a common foundation for other insertion electrodes, as long as their redox behaviors are analogous to that of PB. © 2002 The Electrochemical Society. All rights reserved.
SDGs
Type
journal article