Solid electrolyte properties of sulfonic acid functionalized mesostructured porous silica

The proton conduction properties of mesostructured templated-porous silica functionalized with sulfonic acid groups, grafted within the pores, were determined in dry nitrogen, at 100% relative humidity and in presence of liquid water using impedance spectroscopy. The proton conductivity (a) was strongly affected by the presence of water, changing by up to six orders of magnitude. Fully hydrated materials exhibited conductivities above 10 (2) S/cm at room temperature which places them among the most promising solid electrolytes. The impedance spectra showed up to three arcs with resolved time constants. Equivalent circuits worked out for the simulation of the experimental data were used for analysis of the transient behavior of the material after introduction of water. (C) 2002 Elsevier Science B.V. All rights reserved.