| 초록 |
Methanol crossover is a crucial problem of Nafion membrane for direct methanol fuel cells (DMFCs). α-Zirconium phosphate (α-ZrP) which functions a barrier for methanol crossover and has a moderate proton conductivity has been introduced to fabricate novel nanocomposites with Nafion. Exfoliated α-ZrP in ethanol can be obtained with ultra-sonication and surfactant (tetrabutylammonium hydroxide, TBA+OH-). Diaminoalkane as linking agent is used to render ionic bonding with α-ZrP and Nafion: one end amine group in diaminoalkane is ionic-bonded with -POH group of α-ZrP, and the other end amine group with -SO3H group in Nafion. A novel α-ZrP/Nafion nanocomposite electrolyte membrane was fabricated by coating the α-ZrP/Nafion solution on Nafion 117 membrane. By using X-ray diffraction (XRD) and transmission electron microscopy (TEM), it was found that α-ZrP was well-dispersed in Nafion matrix. Scanning electron microscopy (SEM) measurements and energy dispersive X-ray analysis (EDX) indicated that a lot of α-ZrP sheets exist in the nanocomposite layers which have uniform thickness and good adhesion with Nafion 117 membrane. There was a significant decreases in methanol permeability of the nanocomposite electrolyte membrane compared with Nafion 117 membrane, while the proton conductivity of that was slightly less than that for Nafion 117 membrane. |
