Mathematical modeling of the transport characteristics of a PVDF-based cation-exchange membrane with low water content

New effective ion-exchange membranes are needed for a variety of applications, with a particularly pressing need for membranes used in fuel cells and membrane water electrolysis. PVDF-based membranes are promising for these and other applications. Two samples of such membranes with a low water conte...

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Bibliographic Details
Published in:	Journal of membrane science Vol. 707; p. 122931
Main Authors:	Kislyi, A.G., Kozmai, A.E., Mareev, S.A., Ponomar, M.A., Anokhin, D.V., Ivanov, D.A., Umarov, A.Z., Maryasevskaya, A.V., Nikonenko, V.V.
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 01-07-2024
Subjects:	Conducting channels Conductivity Diffusion permeability Ion-exchange membranes Percolation PVDF-based Transport numbers Water content Diffusion permeability Water content Conductivity Percolation Ion-exchange membranes Transport numbers Conducting channels PVDF-based
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Summary:	New effective ion-exchange membranes are needed for a variety of applications, with a particularly pressing need for membranes used in fuel cells and membrane water electrolysis. PVDF-based membranes are promising for these and other applications. Two samples of such membranes with a low water content are studied. The interest in the behavior of these samples is that with an increase in the bathing NaCl solution concentration, the diffusion permeability decreases, whereas usually it increases along with increasing membrane conductivity. The hypothesis is that with increasing concentration, the water content decreases even more, which leads to a narrowing of the intercluster ion-conducting channels and a reduction in the effective mobility of coions, since the latter have to go around narrowed sections of channels. To simulate the concentration dependence of conductivity, diffusion permeability and transport numbers for the two above samples, the microheterogeneous model is extended to describe the loss of water with increasing external concentration and take into account the decrease of coion percolation through the membrane. The results of simulation are compared with the experimental data. [Display omitted] •Concentration-dependent transport properties of PVDF-based membranes are studied.•Percolation is introduced in mechanistic-thermodynamic-microheterogeneous model.•Membrane microheterogeneous structure is taken into account.•Effect of low-water content on membrane structure is described.•Dependence of coion diffusion coefficients on water content and swelling degree is simulated.
ISSN:	0376-7388 1873-3123
DOI:	10.1016/j.memsci.2024.122931