Advanced Mesostructured Hybrid Silica−Nafion Membranes for High-Performance PEM Fuel Cell

Abstract

Organic−inorganic hybrid membranes of Nafion and mesoporous silica containing sulfonic acid groups were synthesized using the sol−gel process with the goal of increasing the proton conductivity and water retention at higher temperatures and lowering relative humidities as well as improving the dimensional stability. These hybrid membranes were prepared via in situ co-condensation of tetraethoxysilane and chlorosulfonylphenethylsilane via self-assembly route using organic surfactants as templates for the tuning of the architecture of the silica or hybrid organosilica components. In this paper, we describe the elaboration and characterization of new hybrid membranes all the way from the precursor solution to the evaluation of the fuel cell performances. These hybrid materials were extensively characterized with the determination of their physicochemical and electrochemical properties. The membrane containing functionalized silica showed a higher ionic exchange capacity and greater water management than standard Nafion. The hybrid membranes showed improved proton conductivity at 95 °C and over the whole range of relative humidity in comparison to recast Nafion and Nafion 112 membranes.