Sulfonated polybenzimidazole for low-alkalinity ion solvating membrane water electrolysis
Abstract Ion solvating membranes based on polybenzimidazole (PBI) are alternatives to diaphragms in alkaline water electrolysers but can typically only operate with electrolyte concentrations of 15–30 wt% KOH. Sulfonation of the membrane broadens the operational range to 0.1 wt%–30 wt%; however, the swelling of sulfonated para -PBI means that crosslinkers are needed, complicating membrane fabrication and decreasing alkaline stability. Here we report a non-crosslinked PBI membrane with a 50% degree of sulfonation that shows a high room temperature conductivity in 1 M KOH of 135 mS cm −1 . We did not observe degradation in a 6-month alkaline stability test at 80 °C. Using this membrane in an anion-exchange membrane water electrolyser, we report a current density of 4.8 A cm −2 at 2 V (3 M KOH at 80 °C; Pt and NiFe electrode catalysts); the H 2 crossover to the O 2 side remained <2%. Using non-platinum group metal electrodes and a polyphenylene sulfide-reinforced membrane, a cell operated for >1,000 h without failure.
Authors
- David Aili
- Fatemeh Razmjooei (ORCID: https://orcid.org/0000-0002-8355-6252)
- Hyun S. Park (ORCID: https://orcid.org/0000-0002-7960-9729)
- Olga Żurowska (ORCID: https://orcid.org/0009-0005-1979-6031)
- Artur Michalak (ORCID: https://orcid.org/0000-0003-1408-5474)
- Franz Egert (ORCID: https://orcid.org/0009-0005-7415-7830)
- Dirk Henkensmeier
- Mikkel Rykær Kraglund (ORCID: https://orcid.org/0000-0002-1229-1007)
- Muhammad Mara Ikhsan (ORCID: https://orcid.org/0000-0003-4360-1773)
- Syed-asif Ansar
- Kamal Ghotia
- Chaeyeon Yang
- Maria Rózga
Institutions
- University of Stuttgart (DE)
- Jagiellonian University (PL)
- Seoul National University (KR)
- Seoul National University of Education (KR)
- Korea University (KR)
- Fuel Cells and Hydrogen (BE)
- Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (DE)
- Stuttgart Technical University of Applied Sciences (DE)
- National University (SD)
- Korea Institute of Science and Technology (KR)
- Korea University of Science and Technology (KR)
- Technical University of Denmark (DK)
Publication Details
- Journal
- Nature Energy
- Published
- 2025-10-10
- DOI
- https://doi.org/10.1038/s41560-025-01876-9
- Citations
- 5
- Primary Topic
- Fuel Cells and Related Materials
- Type
- article
- Field-Weighted Citation Impact
- 3.65
Funders
- European Commission
- Korea Institute of Science and Technology
- Narodowym Centrum Nauki
- Infrastruktura PL-Grid
- European Regional Development Fund
- Academic Computer Centre Cyfronet, AGH University of Science and Technology