Non-equilibrium steady states of electrolyte interfaces
- The non-equilibrium steady states of a semi-infinite quasi-one-dimensional univalent binary electrolyte solution, characterised by non-vanishing electric currents, are investigated by means of Poisson-Nernst-Planck (PNP) theory. Exact analytical expressions of the electric field, the charge density and the number density are derived, which depend on the electric current density as a parameter. From a non-equilibrium version of the Grahame equation, which relates the total space charge per cross-sectional area and the corresponding contribution of the electric potential drop, the current-dependent differential capacitance of the diffuse layer is derived. In the limit of vanishing electric current these results reduce to those within Gouy-Chapman theory. It is shown that improperly chosen boundary conditions lead to non-equilibrium steady state solutions of the PNP equations with negative ion number densities. A necessary and sufficient criterion on surface conductivity constitutive relations is formulated which allows one to detect such unphysical solutions.
Author: | Markus Bier |
---|---|
Persistent identifier: | https://doi.org/10.1088/1367-2630/ad19a9 |
Parent Title (English): | New Journal of Physics |
Document Type: | Article |
Language: | English |
Year of publication: | 2024 |
Publishing Institution: | Technische Hochschule Würzburg-Schweinfurt |
Release Date: | 2024/03/07 |
Tag: | Poisson-Nernst-Planck theory, non-equilibrium steady state, electrolyte interface, Gouy-Chapman model |
Volume: | 26 |
Issue: | 1 |
First Page: | 013008 |
Institutes and faculty: | Fakultäten / Fakultät für angewandte Natur- und Geisteswissenschaften |
Open access colour: | Gold |