A Simple Self-Cross-Linking Strategy for Double-Layered Proton Exchange Membranes with Improved Methanol Resistance and Good Electrochemical Properties for Passive Direct Methanol Fuel Cells

A series of new double-layered proton exchange membranes (PEMs) with improved methanol resistance has been successfully prepared through the self-cross-linking of cyano groups catalyzed by super acid. The experimental results indicate that the variation of mixed solvents and cross-linking time have important effects on the morphology of the membrane. Moreover, the presence of a methanol barrier layer with appropriate thickness can significantly improve the performance of cross-linking PEMs, including proton conductivity, proton selective permeability, and electrochemical property. The passive direct methanol fuel cells (DMFCs) based on these cross-linking membranes present a maximum power density of 45.0 mW cm(-2) at 25 degrees C, which is superior to the values of a pristine membrane (24.5 mW cm(-2)) and a commercial Nafion 115 membrane (29.3 mW cm(-2)) The present study provides a new idea for the design and development of high-performance PEM materials for DMFC applications.