Standard Article

Conductivity, permeability, and ohmic shorting of ionomeric membranes

Advances in Electrocatalysis, Materials, Diagnostics and Durability

Conductive membranes for low-temperature fuel cells

Characterization

  1. C. K. Mittelsteadt,
  2. H. Liu

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f500025

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Mittelsteadt, C. K. and Liu, H. 2010. Conductivity, permeability, and ohmic shorting of ionomeric membranes. Handbook of Fuel Cells. .

Author Information

  1. Giner Electrochemical Systems, LLC, Newton, MA, USA

Publication History

  1. Published Online: 15 DEC 2010

Abstract

To minimize resistance losses, polymer electrolyte membranes are being fabricated thinner and with a higher acid content. This affects membrane resistance, gas permeability, and membrane durability. Models for the conductivity of perfluorinated sulfonic acid (PFSA) and sulfonated aromatic hydrocarbons are developed on the basis of the conductivity of small-molecule analogues. These models are used to project an upper bound for conductivity of these systems. Gas permeability of PFSA membranes is modeled by separating transport into the hydrophobic and hydrophilic regions. Generally it is found that the gas permeability of PFSA materials is higher than that of hydrocarbon membranes. Two types of ohmic shorting tests are conducted on membranes of various thicknesses as well as membranes with an expanded poly(tetrafluoroethylene) support. Membranes with thickness above 90 μm do not short by these tests. For thinner membranes, both the addition of a catalyst layer and the poly(tetrafluoroethylene) support mitigates ohmic shorting.

Keywords:

  • polymer electrolyte membrane;
  • Nafion;
  • gas permeability;
  • conductivity;
  • ohmic shorting;
  • fuel cell vehicles;
  • model