Pre-Stretched Low Equivalent Weight PFSA Membranes with Improved Fuel Cell Performance

  • Zhang W
  • Wycisk R
  • Kish D
 et al. 
  • 13

    Readers

    Mendeley users who have this article in their library.
  • 2

    Citations

    Citations of this article.

Abstract

Uniaxial stretching of recast perfluorsulfonic acid (PFSA) films was used to promote desirable morphological changes for 3M Company’s 825 equivalent weight (EW) and 733 EW PFSA polymers. Stretching to a draw ratio (DR) of four was followed by a high temperature annealing step in order for the morphological changes to be permanent. For 825 EW PFSA, stretching increased the polymer crystallinity by 22.5%, with a reduction in methanol permeability and a small increase in proton conductivity. In direct methanol fuel cell tests at 60◦C with 1.0 M methanol, the power density at 0.4 V with a DR = 4 stretched 825 EW membrane (72 mW/cm2) was considerably greater than that obtained with a solution-cast membrane (28 mW/cm2) or with a commercial Nafion 117 membrane (55mW/cm2). For 733 EW PFSA, stretching promoted the formation of ordered ionic domains leading to an increase in proton conductivity. There was also a substantial increase in the polymer’s α-transition temperature and an improvement in membrane mechanical properties after stretching. The lifetime of a stretched 733 EW PFSA membrane (DR = 4) was extended by a factor of 3.5 as compared to that of a solution-cast film in an open circuit voltage humidity cycling test at 80◦C

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • W. Zhang

  • R. Wycisk

  • D. L. Kish

  • P. N. Pintauro

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free