Title
Non-ohmic resistance of multiple ion-exchange membranes in series
Author
Kramer, Zino (TU Delft Electrical Engineering, Mathematics and Computer Science)
Contributor
Kelder, E.M. (mentor) 
Vermaas, D.A. (graduation committee)
Haverkort, J.W. (graduation committee)
den Haan, S. (mentor)
Degree granting institution
Delft University of Technology
Date
2022-08-16
Abstract
This research aims to analyse the non-ohmic resistance of multiple ion-exchange membranes (IEM) in series, for a better understanding of membrane resistances. These membranes can be found in series in energy storage systems such as acid-base flow batteries (ABFB).
The effect of different current densities on the ohmic and non-ohmic resistance of bipolar membranes (BPM), under forward and reverse bias were studied using electrochemical impedance spectroscopy (EIS). Hereafter, an anion exchange membrane (AEM), cation exchange membrane (CEM) and BPM were examined individually and in series using EIS, to compose a simplified equivalent circuit for a whole ABFB triplet.
For the effect of different current densities on the BPM, an exponential decline of the non-ohmic resistance of the diffusion boundary layer (DBL) was found as a function of the current density. Under forward bias, the DBL resistance becomes significant. The resistance of the water dissociation reaction (WDR) was minimal under all current densities. Flow experiments validate a depletion and enrichment of the DBL during water association and dissociation, respectively.
To compose a simplified equivalent circuit for an AEM, BPM and CEM in series, it was found that the specific resistances of all membranes can be summed at their respective frequencies. This made it possible to construct a simplified equivalent circuit for a whole triplet containing an AEM, BPM and CEM.
Subject
Electrochemical impedance spectroscopy
Ion Exchange Membranes
Acid-base flow battery
Bipolar membrane/BPM
Membrane resistance
Diffusion boundary layer
Membrane characterisation
Equivalent circuit
To reference this document use:
http://resolver.tudelft.nl/uuid:29d66cd5-a737-4a01-9c1e-81ef47fc6884
Embargo date
2024-08-16
Part of collection
Student theses
Document type
master thesis
Rights
© 2022 Zino Kramer