Decoupling ion conductivity and fluid permeation through optimizing hydrophilic channel morphology

Peter Po Jen Chu, Yu Shin Fang, Yu Chen Tseng

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Approaches to improve membrane ion conductivity usually leads to higher degree of swelling, more serious fuel cross-over and often sacrificed membrane mechanical strength. Preserving all three main membrane properties is a tough challenge in searching high ion conducting fuel cell membrane. The long standing dilemma is resolved by decoupling ion conduction and fluid permeation property by creating optimized channel morphology using external electric field poling. Success of this approach is demonstrated in the proton conducting membrane composed of poly(ether sulfones) (PES) and sulfonated poly(ether ether ketone) (sPEEK, degree of sulfonation=50%) composites prepared under electric field poling condition. The external field enhanced the aromatic chain ordering from both sPEEK and PES and improved the miscibility. This induced interaction is conducive to the formation of more densely packed amorphous domains that eventually leads to preferentially ordered hydrophilic proton conducting channels having a average dimension (3 nm) smaller than that in generic sPEEK or Nafion. The narrower but more ordered channel displayed much lower methanol permeability (3.17×10-7 cm2/s), and lower swelling ratio (31.20%), while the conductivity (∼10-1 S/cm) is higher than that of Nafion, or sPEEK at higher (64%) degree of sulfonation. The composite is chemically stable and highly durable with improved membrane mechanical strength. Nearly 50% increase of DMFC power output is observed using this membrane, and the best power density is recorded at 155 mA/cm2 (80 °C, 1M Methanol).

Original languageEnglish
Title of host publicationVIII International Conference on "Times of Polymers and Composites"
Subtitle of host publicationFrom Aerospace to Nanotechnology
EditorsAlberto D'Amore, Luigi Grassia, Domenico Acierno
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735413900
DOIs
StatePublished - 18 May 2016
Event8th International Conference on Times of Polymers and Composites: From Aerospace to Nanotechnology - Ischia, Naples, Italy
Duration: 19 Jun 201623 Jun 2016

Publication series

NameAIP Conference Proceedings
Volume1736
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference8th International Conference on Times of Polymers and Composites: From Aerospace to Nanotechnology
Country/TerritoryItaly
CityIschia, Naples
Period19/06/1623/06/16

Keywords

  • electric field poling
  • fluid dynamics
  • Fuel cell
  • ion conductivity
  • ion exchange membrane

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