XRD and XPS analysis of the degradation of the polymer electrolyte in H2–O2 fuel cell

Nafion® is frequently used as electrolyte membrane in polymer electrolyte fuel cells (PEFC). In this Letter the degradation of the Nafion® polymer electrolyte was investigated using X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD showed that the electrode potential and low gas humidification temperature could decrease the crystallinity of Nafion®. XPS analysis indicated that the Nafion® was decomposed in the hydrogen potential region of the fuel cell, through the interaction of the hydrophobic (CF2)n groups of the membrane with H or/and C atoms.