Preparation of Nafion 117™-SnO2 composite membranes using an ion-exchange method

Nafion 117™-SnO2 composite membranes were prepared by in-situ particle formation using an ion-exchange method. SnO2 was incorporated into Nafion 117™ membranes by ion-exchange in solutions of SnCl2. 2 H2O in methanol, followed by oxidation to SnO2 in air. By adjustment of the concentration of SnCl2 ∙ 2 H2O used in the ion-exchange step, compositions ranging from 2 to 8 wt.% SnO2 with SnO2 homogeneously distributed as nanoparticles were obtained.The prepared nanocomposite membranes were characterized by powder XRD, 119Sn MAS NMR spectroscopy, electrochemical impedance spectroscopy, water uptake, tensile stress–strain measurements and thermogravimetric analysis. A SnO2 content around 4 wt.% gave a significant increase in membrane stiffness without losses in conductivity.