Chemical Modification of Perfluorosulfo-nated Membranes with Pyrrole for Fuel Cell Application: Preparation, Characteri-sation and Methanol Transport

• Published in: Fuel cells (Weinheim an der Bergstrasse, Germany) Germany), 2005-08, Vol.5 (3), p.398-405
• Main Authors: Xu, F., Innocent, C., Bonnet, B., Jones, D. J., Rozière, J.
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Fuel Cells; Hydro-Organic Media; Ion Exchange Membranes; Material chemistry; Methanol Crossover; Polymers; Pyrrole-Modified Nafion
• ISSN: 1615-6846; 1615-6854
• DOI: 10.1002/fuce.200400077

In situ chemical polymerisation of pyrrole in Nafion®‐115 membranes produces a composite material that shows a decrease in methanol crossover compared with the non‐modified material, and a good protonic conduction (area resistance of 0.65 Ω cm2). Pyrrole is impregnated from an appropriate solvent, and the choice of oxidising agent (hydrogen peroxide, ammonium peroxodisulfate) provides two types of modified membrane. Membrane characterisation using infrared spectroscopy shows the presence of pyrrole oligomers and polymer, but the proton conductivity is lower than that of the Nafion®‐115 membrane by only a factor 2–3. Methanol transport measurements in 2 mol dm–3 methanol with and without application of an electric field show ca. 30% lower crossover for the pyrrole‐modified membranes. In single cell hydrogen – oxygen fuel cell tests, the pyrrole‐modified Nafion® prepared using hydrogen peroxide oxidant gave higher open circuit voltage and current density, in particular at > 80 °C, than non‐modified Nafion®‐115.