The development of new proton exchange membranes for PEMFC has to be related to the
membrane processing as it can change drastically the final properties of the material. Indeed, for the
same material, a membrane prepared by a solvent-casting process has a lower lifetime than an
extruded one. The proton conduction of the membrane can also be dependent on the membrane
processing, especially when some removable plasticizers are used to perform the membrane
extrusion. Some residual porosity, left in the material after removing the plasticizer, is suspected to
enhance the proton conduction of the film. Fuel cell experiments have shown that extruded
sulfonated polysulfone membrane can give the same performance as a Nafion® reference
membrane whereas the proton conductivity of PSUs is twenty times lower than the Nafion® one.
Additional improvements of the membrane properties can also be expected by adding some proton
conductive fillers to the organic polymer. This approach enhances the proton conductivity of
sulfonated polysulfone to values similar to Nafion®. On the other hand, when Nafion® is used as a
matrix for the proton conductive fillers, a very significant improvement of fuel cell performance is
obtained.
Anhydrous Proton Conduction of Natural Aromatic Polymer: Preparation of Ligninsulfonic Acid-Heterocyle Composite and its Proton Conductivity
