High Performance Fluorine Free Membranes for Direct Methanol Fuеl Cells

Direct Methanol Fuel Cells (DMFC) were developed for a variety of applications and different markets. Such applications range from micro fuel cells as a battery replacement in small electronic devices such as mobile phones or laptops. Thus, primary advantages of DMFCs over existing battery technology are increased power density and energy storage capacity as well as the potential for an uninterrupted operations.

 A number of perfluorinated proton conducting polymeric membranes was created for fuel cell application.

However, until now the main problems of their applications remain elevated cost of production and high methanol crossover.

Pirelli Labs team has created a new family of membranes for DMFC application based on cheap fluorine free chemistry with possibility of the membrane properties tuning in high range.

The interpenetrated polymers structure characterized by a crystalline polyolefine part, free from the presence of sulfoaromatic chains and  an amorphous part rich by such chains divided the material in hydrophobic and hydrophilic areas. The hydrophilic areas create excellent channels of protonic conductivity. The model is presented in figure 1.

The main properties of such type of membranes like protonic conductivity and methanol crossover are presented in table 1.

Methanol Flux (µmol/cm² min)	Conductivity (mS/cm)
<10	>90

These properties of Pirelli Labs fluorine free membranes for DMFC application open the possibility for their wide application. Continuing work on the further improvement of membranes the Pirelli Labs team is strongly concentrated on the development of new types of Membrane Electrode Assembly (MEA) adapted for DMFC application.

Ongoing activities are also focused on the development of membranes tailored for application in neat methanol.