WIAS Preprint No. 2361, (2016)

Boundary conditions for electrochemical interfaces



Authors

  • Landstorfer, Manuel

2010 Mathematics Subject Classification

  • 78A57 35Q35 34B15

2008 Physics and Astronomy Classification Scheme

  • 82.45.Fk, 82.45.Gj, 68.43.Mn, 82.45.-h

Keywords

  • Boundary conditions, double layer charging, charge transfer, current voltage relation, mixture theory, electrode/electrolyte interface

DOI

10.20347/WIAS.PREPRINT.2361

Abstract

Consistent boundary conditions for electrochemical interfaces, which cover double layer charging, pseudo-capacitive effects and transfer reactions, are of high demand in electrochemistry and adjacent disciplines. Mathematical modeling and optimization of electrochemical systems is a strongly emerging approach to reduce cost and increase efficiency of super-capacitors, batteries, fuel cells, and electrocatalysis. However, many mathematical models which are used to describe such systems lack a real predictive value. Origin of this shortcoming is the usage of oversimplified boundary conditions. In this work we derive the boundary conditions for some general electrode-electrolyte interface based on non-equilibrium thermodynamics for volumes and surfaces. The resulting equations are widely applicable and cover also tangential transport. The general framework is then applied to a specific material model which allows the deduction of a current-voltage relation and thus a comparison to experimental data. Some simplified 1D examples show the range of applicability of the new approach.

Appeared in

  • J. Electrochem. Soc., 164 (2017) pp. 3671--3685.

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