Ionic liquids (ILs) are molten salts with tunable composition. The unique physico-chemical properties (e.g., negligible vapor pressure, wide electrochemical window, high thermal stability, low flammability) and the high “tunability” of ILs, which derives from the virtually unlimited number of permutations of cations and anions, make them candidate materials for several applications, including solvents in catalysis, reaction media, electrolytes in energy storage devices, active pharmaceutical ingredients, and lubricating fluids.
Since in most potential applications of ILs the functional behaviors (e.g., catalysts’ selectivity, charge storage of supercapacitors, lubricity) depend on the response of the ions at solid/IL interfaces to external stimuli (electric field, pressure, and temperature), the dependence of the properties and structures of ILs on externally controlled parameters has been the subject of extensive research. In our group, we are currently evaluating the response of ILs at elevated pressures, which is critical for applications in which the ILs are confined in very narrow spaces (e.g., in porous electrodes of energy storage devices) or squeezed between two bodies (e.g., across sliding interfaces). Through the combined use of atomic force microscopy (AFM) and spectroscopic methods, we aim to elucidate the relationship between pressure-induced phase transitions in nanoconfined ILs and funcational performance.
Relevant publications:
- Li, F. Mangolini, Recent Advances in Nanotribology of Ionic Liquids, Experimental Mechanics, accepted, 2021