Anhydrous proton-conducting imidazole triflate-SiO2 composite.

ImidazoleTriflate (ITF)-SiO2 composites xITF-(100-x)SiO2 were prepared by planetary ball-milling method. The structure of the composites was studied by TG-DTA, XRD and FT-IR methods. The ionic conductivity was assessed by alternative current (AC) electrochemical impedance measurement. From XRD results, the crystal size of imidazole triflate became smaller as its loading in xITF-(100-x)SiO2 decreased. With x = 40 weight percent, the calculated crystal size was about 7.3 nm. FT-IR spectra showed the existence of CF3SO3 -···H+ ion aggregates and imidazole-proton bonds. The electrical conductivity of sample x = 50 was about 6.3 × 10-3 Scm-1 at 130 °C under anhydrous condition and about 30 times higher than that of sample x = 100.