Different approaches to obtain functionalized alumina as additive in polymer electrolyte membranes

Abstract A series of sulfated aluminum oxides (S-Al 2 O 3 ), investigated as an electrolyte additive in Nafion membranes, was synthesized via three different methods: (i) sol–gel sulfation starting from alkoxide precursor, (ii) room temperature fumed oxide, and (iii) hydrothermal oxide. Through the characterization S-Al by means X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared (IR) spectroscopy, a higher rate found to be achieved sulfation, coordination state sulfate groups identified monodentate. By using this hydrothermally additive, composite Nafion-based membrane realized compared plain Nafion, thermal analyses fuel cell tests. Although hydration degree for undoped differential scanning calorimetry (DSC), improved retention performance upon increase operation observed electrolyte, confirming stabilizing effect acidic inorganic additive.