Preparation and fuel cell performance of catalyst layers using sulfonated polyimide ionomers

Takuya Omata, Manabu Tanaka, Kenji Miyatake, Makoto Uchida, Hiroyuki Uchida, Masahiro Watanabe

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Sulfonated polyimide (SPI-8) ionomers were used as binders in the catalyst layers, and their fuel cell performance was evaluated. SPI-8 ionomers functioned well in the anode with only minor overpotential even at low humidity (50% relative humidity (RH)). In contrast, the cathode performance was significantly dependent on the content and molecular weight of the ionomers and humidity of the supplied gases. Higher molecular weight of the ionomer caused larger potential drop at high current density at 80 and 100% RH since oxygen supply and/or water discharge became insufficient due to higher water uptake (swelling) of the ionomer. Similar results were obtained at higher ionomer content, because of the increase of thickness in the catalyst layer. The mass transport was improved with decreasing humidity, however, proton conductivity became lower. While the maximum values of j @0.70 V for all membrane electrode assemblies (MEAs) were ca. 0.35 A/cm 2, each electrode could have the different appropriate operating conditions. The results suggest that the parameters such as oxygen supply, proton conductivity, and water uptake and discharge need to be carefully optimized in the catalyst layers for achieving reasonable cathode performance with hydrocarbon ionomers.

Original languageEnglish
Pages (from-to)730-737
Number of pages8
JournalACS Applied Materials and Interfaces
Volume4
Issue number2
DOIs
Publication statusPublished - 2012 Feb 22
Externally publishedYes

Keywords

  • catalyst layers
  • fuel cells
  • hydrocarbon ionomers
  • sulfonated polyimides

ASJC Scopus subject areas

  • Materials Science(all)

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