Nanocomposites of Inorganic Oxides with Ionic Liquids. Synthesis, Properties, Application (Review)

Abstract

The paper is a review of the recent developments in the field of creation and application of new promising composites of ionic liquids with inorganic oxide nanomaterials. The combination of properties of inorganic materials—high thermal stability, chemical inertness, different combinations of dielectric properties and low-temperature melts of organic electrolytes that are characterized, in addition to high ionic conductivity, by low vapor pressure, high thermal stability, solvation ability—is the basis for developing new types of functional materials. The paper considers two types of nanocomposites: physical mixtures—ionic liquids thickened with inorganic oxide fillers and systems formed by porous oxide materials and ionic liquids, in which the ionic liquids can be included into the nanocavities of the inorganic materials. It also describes the methods of synthesizing composite materials of different types. They include methods of direct mixing, sol-gel synthesis of hybrid organo-inorganic mesostructures and inclusion into the inter-layer spaces of natural layered alumosilicates. The paper also discusses mutual effects of ionic liquids and inorganic oxides as well as the role of confinement of an organic electrolyte in the pores of inorganic materials on the formation of new structures, thermal and transport properties of the composites. Possible application areas of the new types of nanocomposites are electrochemical devices (lithium chemical sources of electrical energy, supercapacitors, sensors), environment protection (ion-exchangers, adsorbents of organic pollutants), biomedicine (antibacterial coatings, surface modifiers, gels), functionalized polymer films, plastics.