Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers

Abstract Hydroxide exchange membrane electrolyzers (HEMELs) enable hydrogen production using low-cost, earth-abundant materials. Improving electrode fabrication is integral to enhancing device performance, and ionomer—responsible for transporting hydroxide and mechanically supporting the catalyst—is...

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Main Authors: Abigayle Polsky, Jacob Clary, Alexandra M. Oliveira, Teng Wang, Derek Vigil-Fowler, Lan Wang, Yushan Yan
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Communications Materials
Online Access:https://doi.org/10.1038/s43246-025-00900-5
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author Abigayle Polsky
Jacob Clary
Alexandra M. Oliveira
Teng Wang
Derek Vigil-Fowler
Lan Wang
Yushan Yan
author_facet Abigayle Polsky
Jacob Clary
Alexandra M. Oliveira
Teng Wang
Derek Vigil-Fowler
Lan Wang
Yushan Yan
author_sort Abigayle Polsky
collection DOAJ
description Abstract Hydroxide exchange membrane electrolyzers (HEMELs) enable hydrogen production using low-cost, earth-abundant materials. Improving electrode fabrication is integral to enhancing device performance, and ionomer—responsible for transporting hydroxide and mechanically supporting the catalyst—is a major component. Here, we use experiments and computation to study the effects of relative humidity (RH) during the drying process of poly(aryl piperidinium) ionomer films on HEMEL electrodes. Broadly, the drying environments determine the physical structure and electrochemical traits of the ionomer network. High RH drying yields a highly porous network with excessive water uptake, structural defects, washout, and 64% reduction in hydroxide conductivity. Extremely low RH drying produces an overly compact pore network that hinders hydroxide mobility. In contrast, moderately low RH drying (9% RH) creates an ionomer film with well-balanced traits: excellent mechanical stability and connectivity needed for catalyst retention and hydroxide transport, which improves HEMEL performance by 40% at 1.8 V compared to suboptimal RHs. This research advances HEMEL manufacturing by providing a simple, scalable, and low-cost approach to optimize electrode ionomer films.
format Article
id doaj-art-7a90ffab067249cd8979402ffccc71d1
institution DOAJ
issn 2662-4443
language English
publishDate 2025-08-01
publisher Nature Portfolio
record_format Article
series Communications Materials
spelling doaj-art-7a90ffab067249cd8979402ffccc71d12025-08-20T03:05:06ZengNature PortfolioCommunications Materials2662-44432025-08-01611910.1038/s43246-025-00900-5Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzersAbigayle Polsky0Jacob Clary1Alexandra M. Oliveira2Teng Wang3Derek Vigil-Fowler4Lan Wang5Yushan Yan6Center for Clean Hydrogen, University of DelawareMaterials, Chemical, and Computational Science Directorate, National Renewable Energy LaboratoryCenter for Clean Hydrogen, University of DelawareCenter for Clean Hydrogen, University of DelawareMaterials, Chemical, and Computational Science Directorate, National Renewable Energy LaboratoryCenter for Clean Hydrogen, University of DelawareCenter for Clean Hydrogen, University of DelawareAbstract Hydroxide exchange membrane electrolyzers (HEMELs) enable hydrogen production using low-cost, earth-abundant materials. Improving electrode fabrication is integral to enhancing device performance, and ionomer—responsible for transporting hydroxide and mechanically supporting the catalyst—is a major component. Here, we use experiments and computation to study the effects of relative humidity (RH) during the drying process of poly(aryl piperidinium) ionomer films on HEMEL electrodes. Broadly, the drying environments determine the physical structure and electrochemical traits of the ionomer network. High RH drying yields a highly porous network with excessive water uptake, structural defects, washout, and 64% reduction in hydroxide conductivity. Extremely low RH drying produces an overly compact pore network that hinders hydroxide mobility. In contrast, moderately low RH drying (9% RH) creates an ionomer film with well-balanced traits: excellent mechanical stability and connectivity needed for catalyst retention and hydroxide transport, which improves HEMEL performance by 40% at 1.8 V compared to suboptimal RHs. This research advances HEMEL manufacturing by providing a simple, scalable, and low-cost approach to optimize electrode ionomer films.https://doi.org/10.1038/s43246-025-00900-5
spellingShingle Abigayle Polsky
Jacob Clary
Alexandra M. Oliveira
Teng Wang
Derek Vigil-Fowler
Lan Wang
Yushan Yan
Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
Communications Materials
title Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
title_full Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
title_fullStr Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
title_full_unstemmed Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
title_short Impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
title_sort impact of processing humidity on ionomer film structure and performance in hydroxide exchange membrane electrolyzers
url https://doi.org/10.1038/s43246-025-00900-5
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