Thin catalyst layer deposited on proton-exchange membrane by self-breathing method

Catalyst layers at membrane–electrode interfaces play an important role in the performance of proton-exchange membrane fuel cells. Increasing the effective interface area and reducing the interface charge transfer resistance are key factors in enhancing cell performance. This study reports on a self-breathing process that has been developed to coat a thin catalyst layer on a membrane surface prior to application of Pt/C slurry. To further improve the breathing efficiency, oxygen plasma treatment was applied. The morphology and surface bonding of the processed membranes were characterized by scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. The interface charge transfer resistances of the membrane electrode assemblies were measured by electrochemical impedance spectroscopy. The results show that the charge transfer resistance of the cell with the self-breathing membrane is one order lower than that of a pristine cell.

► We use oxygen plasma and self-breathing technique for membrane modification. ► Oxygen plasma treatment can increase the effective contact area of the membrane. ► XPS spectra show functional groups of C–S, COOH, CF2, CF3 on plasma treated membranes. ► Self-breathed catalyst layer can reduce Rct.