Anhydrous Proton Conducting Inorganic–Organic Composite Membranes Based on Tetraethoxysilane/ Ethyl-Triethoxysilane/Trimethylphosphate and 1-Butyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide

Abstract

In this paper, we report on inorganic–organic composite membranes with anhydrous proton conduction prepared by the sol–gel process with tetraethoxysilane/ethyl-triethoxysilane/trimethylphosphate and 1-butyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide ([BMI][BTSI]) ionic liquid as precursors. The Fourier transform IR spectroscopy, , , and NMR, and thermogravimetric and differential thermal analysis measurements confirmed that the membranes possess good chemical stability and are thermally stable up to . Thermal stability was considerably enhanced by the presence of the inorganic framework and the stability of [BTSI] anion. The conductivity of all the fabricated membranes was measured from −30 to , and a high conductivity of was measured for the 40 wt % [BMI][BTSI] ionic liquid doped membrane at under anhydrous conditions. The hydrogen permeability was decreased from to for the 40 wt % [BMI][BTSI] ionic liquid doped hybrid membrane during temperature increment from 20 to . For 40 wt % ionic liquid doped hybrid membrane, membrane electrode assemblies were fabricated, and a maximum power density value of at as well as a current density of were achieved at under nonhumidified conditions.