Facile preparation of supramolecular ionogels exhibiting high temperature durability as solid electrolytes

Abstract

Ionogels, solid-like materials maintaining many of the physicochemical properties of ionic liquids, have aroused much interest as excellent functional materials. Here, a facile strategy of the preparation of supramolecular ionogels is reported. Benzenetricarboxylic acid (H₃BTC) and Fe(NO₃)₃·9H₂O are selected as gelators, which form stable supramolecular ionogels within several seconds via metal-coordination interactions in the ionic liquids 1-butyl-3-methylimidazolium chloride (bmimCl) and 1-butyl-3-methylimidazolium benzenesulfonate (bmimBsa). The time for preparing ionogels is reduced dramatically. The ionogel Fe–H₃BTC–bmimCl is broken down at 100 °C, but the ionogel Fe–H₃BTC–bmimBsa can remain stable at 150 °C, exhibiting high temperature durability. These ionogels are characterized further by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TG) in detail. In addition, oscillatory rheological measurements and electrochemical measurements show that these ionogels display superior mechanical properties and high conductivity due to the high ionic liquid content.