Crosslinked polymer electrolytes of high pyridine contents for HT-PEM fuel cells

Abstract

This report evaluates a new family of pyridine containing aromatic polyether sulfones as polymer electrolytes for high temperature polymer electrolyte membrane fuel cells (HTPEM FCs). The polymers are prepared by high temperature polyetherification reactions, yielding highly soluble polymers even with pyridine contents as high as 90%. Along with the pyridine content, crosslinking density is also tuned, leading to the enhancement of membrane properties such as film integrity, dimensional stability and doping ability in acidic media. The completion of the crosslinking reaction is enabled by a short thermal pre-treatment, preceding the doping step in H3PO4 85%. Both the linear and the crosslinked membranes show high thermal and oxidative stability. Membranes before and after crosslinking are integrated in single cells where their conductivity and performance are monitored, revealing conductivities above 7 × 10−2 S/cm at temperatures higher than 180 °C.