A novel work-flow to study Ir electrode thinning and dissolution in proton exchange membrane water electrolyzers

• Published in: Journal of power sources 2021-07, Vol.500, p.229978, Article 229978
• Main Authors: Burch, M.J., Lewinski, K.A., Buckett, M.I., Luopa, S., Sun, F., Olson, E.J., Steinbach, A.J.
• Format: Article
• Language: English
• Subjects: Degradation; Electrolyzers; Imaging analytics; Perfluorosulfonic acid (PFSA); Proton Exchange Membrane (PEM); Transmission Electron Microscopy (TEM)
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.229978

In this work, a new workflow to analyze the structural degradation of proton exchange membrane (PEM) water electrolysis catalyst coated membrane (CCM) was developed, utilizing a unique cryo-microtomy sample preparation method, transmission electron microscopy (TEM) imaging, and a semi-automatic image analytics approach. This workflow is used to demonstrate how an iridium based Ir-NanoStructured Thin Film (Ir-NSTF) oxygen evolution reaction (OER) catalyst/electrode degrades over time at various applied currents and show that iridium interpenetrates into the perfluorosulfonic acid (PFSA) PEM, suggestive of degradation mechanism involving iridium dissolution. The utilization of this workflow in future degradation and lifetime measurements is discussed in detail. •The structure of durability-aged oxygen evolution electrodes was characterized.•A new microscopy and image analytics quantification method were developed.•Electrode thickness loss increased with time and operating current density.•Water electrolysis performance did not depend on electrode thickness.•Iridium particles were found within the membrane after testing.