Issue 13, 2024

Meta-kinks are key to binder performance of poly(arylene piperidinium) ionomers for alkaline membrane water electrolysis using non-noble metal catalysts

Abstract

Anion-exchange membrane water electrolysis (AEMWE) is a key technology for the production of green hydrogen at high current densities without the necessity of noble metal catalysts. AEMWE technology does not only rely on chemically stable and highly hydroxide-conducting membranes, but also on ionomer binders, to which additional criteria apply related to swelling, mechanical properties, gas permeability and porosity to form a triple phase boundary with catalyst particles on top of an membrane electrode assembly (MEA). Here, we investigate seven poly(arylene piperidinium)s (PAPs) with different ratios of meta-/para-terphenyl building blocks as binders for non-noble NiFe-LDH catalysts. We first analyze the materials comprehensively in pristine form and subsequently as binders. With increasing content of meta-terphenyl, specific surface area, water uptake, swelling ratio and ion-conductivity increase continuously, with the latter ranging from 145 to 216 mS cm−1 at 80 °C. We elucidate binder performance from rotating disk electrode experiments of oxygen evolution reactions (OER) catalysed by nickel–iron layered double hydroxides (NiFe-LDH) under AEMWE working potentials. Here, an increasing content of meta-kinks leads to improved catalyst utilization, superior OER performance and improved electrode stability. Finally, AEMWE single cell tests show a strong improvement in current density when altering binders from exclusively para- to meta-terphenyl in the polymer backbone. Current densities as high as 1000 to 1700 mA cm−2 at 1.8 V and 3000 mA cm−2 at 2.0 V are measured for the binder with exclusive meta-terphenyl kinks. The results highlight the role of the binder for AEMWE performance as well as the importance of its individual optimization aside from membrane properties.

Graphical abstract: Meta-kinks are key to binder performance of poly(arylene piperidinium) ionomers for alkaline membrane water electrolysis using non-noble metal catalysts

Supplementary files

Article information

Article type
Paper
Submitted
10 Nov 2023
Accepted
15 Feb 2024
First published
16 Feb 2024
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2024,12, 7826-7836

Meta-kinks are key to binder performance of poly(arylene piperidinium) ionomers for alkaline membrane water electrolysis using non-noble metal catalysts

R. Weber, M. Klingenhof, S. Koch, L. Metzler, T. Merzdorf, J. Meier-Haack, P. Strasser, S. Vierrath and M. Sommer, J. Mater. Chem. A, 2024, 12, 7826 DOI: 10.1039/D3TA06916H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements