New cross-linked interfacial layer on hydrocarbon membrane to improve long-term stability of polymer electrolyte fuel cells

In order to enhance the chemical compatibility of membrane-electrode assembly (MEA) interface, the cross-linked interfacial layer was coated on the cathode side of the hydrocarbon membrane. The interfacial layer, which consists of the sulfonated poly(ether ether ketone) (sPEEK) and the Nafion, provided good adhesion between the sPEEK membrane and the Nafion based electrode. As a result, the interfacial layer coated MEA (i-MEA) showed distinct performance enhancement after wet-dry cycling test, compared with the pristine MEA. The improved cell performance is attributed to the interfacial layer that enhances dimensional stability of the membrane and makes interface chemically more compatible. Various physical property measurements and electrochemical characterizations consistently support the interfacial layer effect for the improved long-term stability.