Standard Article

Chemical and mechanical membrane degradation

Advances in Electrocatalysis, Materials, Diagnostics and Durability

Conductive membranes for low-temperature fuel cells

Membrane durability

  1. W. K. Liu,
  2. S. J. C. Cleghorn,
  3. B. E. Delaney,
  4. M. Crum

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f500028

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Liu, W. K., Cleghorn, S. J. C., Delaney, B. E. and Crum, M. 2010. Chemical and mechanical membrane degradation. Handbook of Fuel Cells. .

Author Information

  1. W.L. Gore and Associates, Elkton, MD, USA

Publication History

  1. Published Online: 15 DEC 2010

Abstract

In order to advance the fundamental understanding of the mechanism of polymer electrolyte membrane degradation and facilitate the development of new technologies, it is imperative to establish reliable, critical tests. It is now widely recognized that membrane degradation and failure proceeds by two interacting mechanisms: ionomer chemical degradation and membrane mechanical failure. This article focuses on the test methods developed that both separate and accelerate these two individual mechanisms, as well as the mechanistic learnings that have been discovered. In situ uniform fuel cell and tradition fuel cell experiments have been used to explore operational effects such as current density, relative humidity, membrane iron content, and cyclic operation on the rate of ionomer chemical degradation. In addition, new ex situ vapor-phase Fenton's reagent experiments have been used to further determine why fuel cell ionomer degradation rates do not always correlate with the results of traditional Fenton's reagent tests. In addition, in-cell relative humidity cycling tests are conducted in an inert environment to isolate the mechanical failure mode of fuel cell membranes, and then fuel cell reactants are introduced to combine mechanical and chemical degradation mechanisms. At this point, the relative rates of the two mechanisms are explored. Finally, results of long-term fuel cell tests are reported at more realistic conditions for today's automotive applications.

Keywords:

  • polymer electrolyte membrane fuel cell (PEMFC);
  • perfluorosulfonic acid;
  • ionomer chemical degradation;
  • durability;
  • mechanical failure;
  • OCV hold;
  • relative humidity cycling