METHOD FOR PREPARING AN ENHANCED PROTON EXCHANGE MEMBRANE AND ENHANCED PROTON EXCHANGE MEMBRANE

摘要

Styrene radiation grafted ETFE-based proton conducting membranes are subject to degradation under fuel cell operating conditions and show a poor stability. Lifetimes exceeding 2'000 h can only be achieved with crosslinked membranes. In this patent application, a novel approach based on the increase of the intrinsic oxidative stability of uncrosslinked membranes is addressed. Hence, the co-grafting of styrene with methacrylonitrile (MAN), which possesses a protected ±-position and strong dipolar pendant nitrile group, onto 25 µm ETFE base film is disclosed. Styrene / MAN co-grafted membranes were compared to styrene based membrane in durability tests in single H 2 /O 2 fuel cells. It is shown that the incorporation of MAN dramatically improves the chemical stability. The membrane preparation based on the copolymerization of styrene and MAN shows encouraging results and offers the opportunity of tuning the MAN and crosslinker content to enhance the oxidative stability of the resulting fuel cell membranes.