Preparation of a Novel Composite Material Based on a Nafion® Membrane and Polypyrrole for Potential Application in a PEM Fuel Cell

Abstract

The process of embedding polypyrrole (PPy) on the surface of a Nafion Ò membrane was studied. Three methods of PPy synthesis directly on the membrane surface were compared. The diffusion method based on the separation of monomer and oxidant (peroxidisulphate) solutions by the membrane to be modified is proposed as the most promising one. The monomer diffuses through the membrane to the oxidant side, where it is polymerized. In this case sulphate is incorporated into the film as a counter-ion. PPy film prepared in this way adheres well to the Nafion Ò surface and shows promising electrochemical activity. The permeability of the composite for monomer in comparison to self-standing Nafion Ò film is reduced significantly. This may be important for the potential application of this composite, especially in a direct methanol fuel cell, as an alternative membrane-electrode assembly (MEA), particularly with regard to the currently used MEA's permeability for fuel.

Utilization of Nafion®/conducting polymer composite in the PEM type fuel cells

“…The electrocatalytic activity of the film is documented by the cyclic voltammetric polarization curves shown in Figure 6. It was found that a charge corresponding to the redox processes in the PPy film increased linearly with its thickness [9]. This offers an opportunity for a fast, nondestructive, in situ rough estimate of the synthesized film thickness.…”

“…A diffusion method for synthesis of CP directly on the PEM surface was proposed as an alternative approach [9] based on the work of Hsu [10]. A broader characterization of these composites is still missing.…”

“…The Nafion Ò /CP composite was synthesized by the diffusion method described in [9]. The synthesis of Nafion Ò /PPy was conducted at the room temperature.…”

“…For the synthesis of CP on the surface of the Nafion Ò membrane the diffusion method has been selected [9]. It allows simple and reproducible synthesis of compact, well adhesive CP film on the PEM surface.…”

Synthesis and Properties of Electroconductive Polymeric Composite Material Based on Polypyrrole

“…Polypyrrole can be obtained by chemical or electrochemical synthesis [12][13][14][15][16]. Chemical polymerization makes it possible to form PPy coatings on the objects of different geometry (microspheres, solid, and porous films, etc.)…”