Morphological investigation of Nafion/TiO2 nanocomposite membranes of PEM Fuel Cell

Effect of morphology on the water uptake of proton exchange composite membranes, which are used in proton exchange membrane (PEM) fuel cells, were investigated in this study. Nafion/TiO2 nanocomposite membranes have been prepared by in-situ sol-gel and casting methods. For sol-gel method, preformed Nafion membranes were soaked in tetrabutylortotitanate (TBT) and methanol solution. Different reaction time causes production of different amount of titanium dioxide particles by the in-situ sol-gel inside the cluster of Nafion. In order to compare synthesis methods, a Nafion-TiO2 composite membrane is fabricated with 3%wt of TiO2 particles by the solution casting method. The membranes were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDXA) and for the water uptake. X-Ray spectra of the composite membranes indicate presence of TiO2 in the modified membranes. In case of a same doping level, sol-gel method produces more uniform distribution of Ti particles in Nafion/TiO2 composite membrane than the casting method. Water uptake of Nafion/TiO2 membrane with 3% of doping level is 51% higher than that of the pure Nafion membrane. Among the nanocomposite membranes, the sample with 2-3wt % of TiO2 content exhibits no agglomeration of particles but higher water uptake.

Keywords:

Proton exchange membrane fuel cell , Nanocomposite membrane , Nafion , Water uptake , sol-gel