Aging Gracefully? Investigating Iridium Oxide Ink's Impact on Microstructure, Catalyst/Ionomer Interface, and PEMWE Performance

Xiang Lyu, Jayson Foster, Robin Rice, Elliot Padgett, Erin Creel, Jianlin Li, Haoran Yu, David Cullen, Nancy Kariuki, Jae Park, Deborah Myers, Scott Mauger, Guido Bender, Svitlana Pylypenko, Alexey Serov

Research output: Contribution to journalArticlepeer-review

7 Scopus Citations


In this study, we conducted a thorough investigation of the impact of aging iridium oxide (IrO2) perfluorosulfonic acid ionomer ink for up to 14 days on the properties of the ink and the resulting catalyst layers. We examined ink properties, such as zeta potential, dynamic light scattering (DLS), density, surface tension, and rheology, as functions of ink aging time. To evaluate the microstructure and catalyst/ionomer interface, we employed transmission electron microscopy (TEM), X-ray scattering, and X-ray photoelectron spectroscopy (XPS) techniques. Furthermore, we assessed the effect of ink aging on the performance of proton exchange membrane water electrolyzers (PEMWEs). Our findings reveal that most ink properties remain stable for 14 days. The variations in PEMWE cell performance are minimal, and no clear trend is observed in relation to ink aging time. This study demonstrates that the effects of aging the inks for 14 days on ink properties, catalyst layer structure, catalyst/ionomer interface, and PEMWE performance are negligible, indicating a substantial time window after ink preparation without any significant changes in its properties. These insights provide crucial guidance for the commercial production and coating processes of ink, which is necessary for scaling up PEM technologies to meet future demand.

Original languageAmerican English
Article number233503
Number of pages10
JournalJournal of Power Sources
StatePublished - 15 Oct 2023

Bibliographical note

Publisher Copyright:
© 2023 Elsevier B.V.

NREL Publication Number

  • NREL/JA-5900-87463


  • Aging effect
  • Iridium oxide
  • Microstructure and interface of catalyst/ionomer
  • XPS


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