Highly Sulfonated and Highly Cross-Linked Poly(ether Ether Ketone) Proton Exchange Membranes

Abstract

Sulfonated poly(ether ether ketone) with pendant carboxylic acid groups was synthesized and used to prepare polymer electrolyte membranes for fuel cell applications. The cross-linking was employed to limit the extreme water uptake and improve the dimensional stability of the membrane. compared with Nafion 117, this cross-linked membranes were likely far more robust. The proton conductivity, water uptake, methanol permeability, thermal stability and cell performance were investigated in order to evaluate its fuel cell applications. The CSPEEK-20% membrane exhibited a high proton conductivity of 0.05 S cm-1, a methanol permeability of 4.3×10-7 cm2 s-1, and a water uptake of 21%. This especially good cell performance, and high oxidative and hydrolytic stability operation suggested that this cross-linked membrane is a promising candidate in fuel cell applications.