Electrolyzer Performance Loss from Accelerated Stress Tests and Corresponding Changes to Catalyst Layers and Interfaces

Shaun Alia, Kimberly Reeves, Haoran Yu, Jaehyung Park, Nancy Kariuki, A. Kropf, Deborah Myers, David Cullen

Research output: Contribution to journalArticlepeer-review

14 Scopus Citations

Abstract

Stress tests are developed for proton exchange membrane electrolyzers that utilize low catalyst loading, elevated potential, and frequent cycling with square- and triangle-waves to accelerate anode catalyst layer degradation during intermittent operation. Kinetics drive performance losses (ohmic/transport secondary) and are accompanied by decreasing exchange current density, decreasing cyclic voltammetric capacitance, and increasing polarization resistance. Decreased kinetics are likely due to a combination of iridium (Ir) migration into electrochemically inaccessible locations in the anode or membrane, Ir particle growth (supported by X-ray scattering), changes in the extent of the Ir oxidation state (supported by X-ray absorption spectroscopy), and anode catalyst layer reordering. Decreasing catalyst/transport layer contact and catalyst/membrane interfacial tearing may add contact resistances and account for increasing ohmic losses. Performance losses for low and moderate catalyst loading, as well as from accelerated and model wind/solar cycling protocols, were likewise dominated by kinetics but vary in severity. Accelerated cycling (1 cycle per minute) appears to reasonably accelerate relevant loss mechanisms and can be used to project electrolyzer lifetime from anode deterioration. Ongoing accelerated stress test development and studies into performance loss mechanisms will continue to be critical as electrolysis shifts to intermittent power and low-cost applications.

Original languageAmerican English
Article number054517
Number of pages14
JournalJournal of the Electrochemical Society
Volume169
Issue number5
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.

NREL Publication Number

  • NREL/JA-5900-78750

Keywords

  • degradation
  • electrolysis

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