Nanopore Ceramic Membranes as Novel Electrolytes for Proton Exchange Membranes

摘要

Silica, titania, and alumina monolithic ceramicchips were prepared via sol-gel processes. All chips weremesoporous, with average pore sizes of 3.5, 7.7, and 2.9 nm forSiO2, TiO2, and Al2O3, respectively. Proton conductivity variedlinearly with relative humidity in Al2O3, whereas a steep increasewas observed for TiO2 and SiO2 between 58 and 81% relativehumidity. The variation was linear with temperature for SiO2, andexponential for TiO2 and Al2O3. At high relative humidity andtemperature, conductivities of 3.9×10-3 and 4.0×10-3 Ωcm-1were measured for TiO2 and SiO2, respectively. These values areless than one order of magnitude lower than that of Nafion, apolymeric material, and because our membranes can be prepared100 times thinner than Nafion, they are possible candidates forapplication as electrolytes in fuel cells.