Design of Graded Cathode Catalyst Layers with Various Ionomers for Fuel Cell Application

Xiang Lyu, Tim Van Cleve, Erica Young, Jianlin Li, Haoran Yu, David Cullen, K. Neyerlin, Alexey Serov

Research output: Contribution to journalArticlepeer-review

14 Scopus Citations


Proton exchange membrane fuel cells (PEMFCs) powered by green hydrogen (H2) have become a promising alternative to conventional hydrocarbon-fueled power generators. Despite technological advancements, further improvements in efficiency, durability, and low-cost production are required for the widespread adoption of PEMFCs. Though numerous approaches to improve PEMFC electrodes have been reported, most strategies utilize a single material set (e.g., one combination of catalyst and ionomer) to improve performance. Alternatively, anisotropic (graded) electrode structures with locally tunable properties may yield superior electrode performance due to improved ionic and gas phase transport. In this work, graded cathode catalyst layers (CCLs) incorporating different ionomers (Nafion D2020, Aquivion D79-25BS, and HOPI) were designed and prepared. Performance screening shows that some of these graded electrode structures have comparable performance to optimized single-ionomer electrode structures (D2020) suggesting some synergistic benefit. Additionally, we show that electrodes with lower equivalent weight (EW) D79 ionomer near the membrane and D2020 ionomer near the gas diffusion media outperformed electrodes with the inverted configuration. Finally, EIS analysis shows some graded ionomer structures (e.g. D79/D2020) have better than expected H+ conductivity, generally leading to better electrode performance. However, further optimization of ionomer content and catalyst ink formulations is needed to improve overall PEMFC performance.

Original languageAmerican English
Article number232530
Number of pages8
JournalJournal of Power Sources
StatePublished - 1 Feb 2023

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

NREL Publication Number

  • NREL/JA-5900-84118


  • Cathode catalyst layer
  • Fuel cell
  • Graded MEA
  • Heavy duty fuel cell truck
  • M2FCT


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