Physicochemical properties of alkaline doped polybenzimidazole membranes for anion exchange membrane fuel cells

L. Zeng, T. S. Zhao, Liang An, G. Zhao, X. H. Yan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

49 Citations (Scopus)

Abstract

Alkaline doped PBI membranes are investigated for their physicochemical properties when employed in alkaline direct alcohol fuel cells. Alkali uptake, water uptake, alcohol permeability, ion conductivity, mechanical strength and evolution of the morphology for the alkaline doped PBI membranes are measured. It is demonstrated that the alkaline doping process has a profound influence on the physicochemical properties of PBI membranes. With a high alkaline doping level, the alkali uptake of alkaline doped PBI membranes reaches 14%. The high alkaline uptake results in a separation of the polymer backbones and partial cleavage of hydrogen bonds, which leads to a reduction in the mechanical strength and an increase the alcohol permeability of alkaline doped PBI membranes. However, the high alkaline doping level is beneficial to the ionic conductivity. The conductivity of alkaline doped PBI membranes increases to 96.1mScm-1 at 363.15K after PBI membranes are doped with 6M KOH solution. Based on these investigations, a mechanism is proposed to interpret the chemical interaction during the alkaline doping process and its influence on physicochemical properties. The existence of a neutralization reaction and the re-establishment of hydrogen bonding networks should be attributed to the property transformation during the alkaline doping process.
Original languageEnglish
Pages (from-to)340-348
Number of pages9
JournalJournal of Membrane Science
Volume493
DOIs
Publication statusPublished - 1 Nov 2015
Externally publishedYes

Keywords

  • Alcohol permeability
  • Anion exchange membrane
  • Fuel cell
  • Ionic conductivity
  • Polybenzimidazole

ASJC Scopus subject areas

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

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