Evaluation of diaphragms and membranes as separators for alkaline water electrolysis

0538945 - ÚMCH 2022 RIV US eng J - Journal Article
Brauns, J. - Schönebeck, J. - Kraglund, M. R. - Aili, D. - Hnát, J. - Žitka, Jan - Mues, W. - Jensen, J. O. - Bouzek, K. - Turek, T.
Evaluation of diaphragms and membranes as separators for alkaline water electrolysis.
Journal of the Electrochemical Society. Roč. 168, č. 1 (2021), č. článku 014510. ISSN 0013-4651. E-ISSN 1945-7111
Institutional support: RVO:61389013
Keywords : alkaline water electrolysis * separator * diaphragm
OECD category: Polymer science
Impact factor: 4.371, year: 2021
Method of publishing: Open access
https://iopscience.iop.org/article/10.1149/1945-7111/abda57

The separator is a critical component for the performance of alkaline water electrolysis as it ensures the ionic contact between the electrodes and prevents the product gases from mixing. While the ionic conductivity of the separator affects the cell voltage, the permeability of the dissolved product gases influences the product gas impurity. Currently, diaphragms are used as separators, the pore system of which is filled with the electrolyte solution to enable the exchange of ions. The breakthrough of the gas phase can be prevented up to a specific differential pressure. A drawback of diaphragms is the requirement of a highly concentrated electrolyte solution to maintain a high ionic conductivity. The usage of anion-exchange membranes could solve this problem. However, the long-term stability of such materials remains unproven. This study compares two pre-commercial diaphragms, an anion-exchange membrane, and an ion-solvating membrane with the state-of-the-art diaphragm ZirfonTM Perl UTP 500. Besides physical characterization, the material samples were evaluated electrochemically to determine the ohmic resistance and the product gas impurities. The results show that the thinner diaphragm outperforms the reference material and that polymer membranes can compete with the performance of the reference material.
Permanent Link: http://hdl.handle.net/11104/0317869