Title: Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers

Abstract

Here we demonstrate a roll-to-roll (R2R) process for direct coating of anode catalyst layers on a polymer electrolyte membrane for low-temperature water electrolysis. To develop this process, we studied catalyst ink formulation, ink-membrane interactions, and coating quality. The catalyst inks were a mixture of iridium oxide (IrO2) and Nafion in a water and alcohol dispersion medium. The type of alcohol (methanol, ethanol, propanols) and water-to-alcohol ratio were varied to determine their influence on membrane swelling, dispersion quality, and coatability. Interactions of the ink dispersion medium with the membrane were characterized using sessile-drop contact-angle measurements. These measurements show that the ratio of water to alcohol has a strong influence on how rapidly the dispersion media is absorbed by the membrane. Rheology of the catalyst inks was measured to understand the microstructure of the catalyst particles in the ink. This analysis found that 1-propanol leads to better dispersion of the IrO2 particles than ethanol. Small-scale coating samples were prepared to understand coating uniformity and formation of irregularities. Subsequently, two water/1-propanol ratios (90:10 and 75:25) were down-selected for large-scale R2R slot die coating. The R2R catalyst-coated membrane (CCM) coating process increased catalyst layer production throughput by over 500x compared to our standard lab-scalemore » spray coating. The CCMs obtained from this process were tested as single-cell membrane electrode assemblies. They exhibited a cell voltage of 1.91 V at a current density of 2 A/cm2, which is comparable to spray-coated CCMs. In conclusion, the work presented here demonstrates a continuous, scalable manufacturing process that eliminates the need for the decal transfer step typically used in CCM production.« less

Authors:

Park, Janghoon  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5897-4241"

Kang, Zhenye  ^[1];

• Search DOE PAGES for author "Kang, Zhenye"
• Search DOE PAGES for ORCID "0000-0002-1731-0705"

Bender, Guido  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3777-4707"

Ulsh, Michael  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3725-8032"

Mauger, Scott A.  ^[1]

• Search DOE PAGES for author "Mauger, Scott A."
• Search DOE PAGES for ORCID "0000-0003-2787-5029"

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+ Show Author Affiliations

1. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Fri Aug 28 00:00:00 EDT 2020

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1665785

Alternate Identifier(s):

OSTI ID: 1651241

Report Number(s):

NREL/JA-5900-76985
Journal ID: ISSN 0378-7753; MainId:24948;UUID:343004bf-a5c4-4df2-96a8-194a80f3feb1;MainAdminID:13714

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Power Sources

Additional Journal Information:

Journal Volume: 479; Journal ID: ISSN 0378-7753

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING; catalyst coated membranes; catalyst inks; iridium oxide; polymer electrolyte membrane water electrolyzers; roll-to-roll; slot-die coating