Phosphoric acid doped crosslinked polybenzimidazole (PBI-OO) blend membranes for high temperature polymer electrolyte fuel cells

N. Nambi Krishnan, Dickson Joseph, Ngoc My Hanh Duong, Anastasiia Konovalova, Jong Hyun Jang, Hyoung Juhn Kim, SukWoo Nam, Dirk Henkensmeier

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Ionically crosslinked acid/base blend membranes of PBI-OO and a sulfonated polysulfone can be covalently crosslinked through aromatic sulfone groups, which form in a thermally induced Friedel-Crafts reaction. Here we systematically compare a series of blend membranes before and after curing. Even though the cured membranes have a lower phosphoric acid uptake even at increased doping time and temperature, they have an improved conductivity and therefore fuel cell performance than the ionically crosslinked membranes. For example, a covalently crosslinked blend membrane containing 5% of the acid component (c-BM 1) reached a conductivity of 260 mS/cm at 160 °C and a relative humidity of 5%, even though the PA uptake was just 266 wt%. In the fuel cell (H2, air, 160 °C), this membrane yielded a peak power density of 452 mW cm−2, about 100 mW cm−2 above that of the commercial meta-PBI membrane. In a long term stability test, the ionically crosslinked membrane uc-BM 1 already failed within 100 h, while the cured c-BM 1 membrane was much more stable. A cured membrane with less PA and higher amount of the acid blend component (c-BM 3) gave a stable performance for over 1000 h, proving that thermally induced sulfone crosslinking strongly increases the stability.

Original languageEnglish
Pages (from-to)416-424
Number of pages9
JournalJournal of Membrane Science
Volume544
DOIs
Publication statusPublished - 2017 Dec 15

Keywords

  • Crosslinked membranes
  • Friedel-Crafts reaction
  • HT PEMFC
  • Phosphoric acid
  • Polybenzimidazole

ASJC Scopus subject areas

  • Biochemistry
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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  • Cite this

    Krishnan, N. N., Joseph, D., Duong, N. M. H., Konovalova, A., Jang, J. H., Kim, H. J., Nam, S., & Henkensmeier, D. (2017). Phosphoric acid doped crosslinked polybenzimidazole (PBI-OO) blend membranes for high temperature polymer electrolyte fuel cells. Journal of Membrane Science, 544, 416-424. https://doi.org/10.1016/j.memsci.2017.09.049