Title

Rigid-Rod Poly(phenylenesulfonic acid) Proton Exchange Membranes with Cross-Linkable Biphenyl Groups for Fuel Cell Applications

Authors

Authors

K. Si; R. Wycisk; D. X. Dong; K. Cooper; M. Rodgers; P. Brooker; D. Slattery;M. Litt

Comments

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Abbreviated Journal Title

Macromolecules

Keywords

POLYMER ELECTROLYTE MEMBRANES; HUMIDITY FIXED-POINTS; HIGH-CONDUCTIVITY; POLYBENZIMIDAZOLES; TEMPERATURE; POLYIMIDES; STABILITY; NAFION; PEMS; Polymer Science

Abstract

Biphenyl was grafted on rigid-rod aromatic poly(p-phenylenesulfonic acids) (IEC similar to 8 mequiv g(-1)) to generate cross-linkable polyelectrolytes. Cross-linking conditions and film properties before and after cross-linking were studied. Films equilibrated between 20 and 30% relative humidity (RH) had tensile moduli of 2 to 1 GPa and broke at 5 to 9% elongation. The moduli decreased as RH increased and dropped drastically at high humidity if the films were not cross-linked. Grafted films had conductivities at 80 degrees C 4-5 times that of Nafion NR-212 over the whole relative humidity range even after cross-linking. The sample reported in detail here had a conductivity of 0.10 S cm(-1) at 120 degrees C and 30% RH. As is usual for this class of materials, even after the loss of 24% of starting sulfonic acid groups by grafting and cross-linking, ionic conductivity was high at low humidity. A membrane electrode assembly (MEA) prepared with this rigid-rod poly(phenylenesulfonic acid) proton exchange membrane and tested in a fuel cell exhibited performance and properties similar to those of Nafion NR-212 films. The power density was similar to 95% of that of the Nafion MEA over the operating range in spite of relatively high hydrogen crossover due to the presence of nanocracks in the membrane.

Journal Title

Macromolecules

Volume

46

Issue/Number

2

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

422

Last Page

433

WOS Identifier

WOS:000314081800011

ISSN

0024-9297

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