Charge-flow and potential shifts in electrochemical double layer emersion

Abstract

Electrochemical double layer emersion and ex situ characterization of the emersed double layer by a variety of spectroscopic and diffraction methods have become powerful techniques for information about the structural properties of the electrode-electrolyte interfacial region. In this work we provide the first theoretical frame for the emersion process in terms of the mutually related electrical and ionic charge distributions in the equilibrated emersed double layer. Specific results have been obtained for a simple model based on a diffuse Gouy-Chapman layer combined with an inner Stern layer, but conceptually straightforward extensions to solvent molecular structural effects and electronic structural effects of the metal electrode also emerge. When the emersed double layer thickness is comparable to the Gouy length of the intact double layer, emersion is accompanied by characteristic electrode potential changes and recharging features which both reflect the electronic and molecular double layer structure and which can be monitored experimentally.