Characterization of Nafion XL membrane for PEMFC after VUV degradation and titanium nitride coating

The surface Nafion^®XL membrane, which suffered from photo-degradation by various VUV irradiations fluences, was investigated by photoemission spectroscopy. After VUV light exposure, the fluorine was dissociated and the CC double bond was then measured. It can be concluded that the membrane degradation was developed, which significantly suppresses the PEMFC efficiency. Degraded membranes were coated with a TiN film by reactive RF-magnetron sputtering to maintain the membrane stability. The modified membranes were investigated by X-ray absorption spectroscopy, X-ray photoelectron spectroscopy and small and wide angle X-ray scattering. The performance of the fuel cell using uncoated and TiN coated membranes decreases with photon fluences; however, the reduction rate of the current density is lower in case of TiN-coated membranes. It was suggested that the TiN film provides greater stability, resulting in a more reliable PEMFC.