Brönsted Acid-Base Ionic Liquids and Membranes as Ion Conducting Materials: Synthesis, Properties and Applications pp. 113-144
Authors: (Harinder Pal Singh Missan, Marisa Singh, Fuel Cell Materials Research Lab, Department of Physics, University of West Indies, Trinidad and Tobago)
Abstract: Ionic liquids (IL’s) are salts in which the ions are poorly coordinated, resulting in these solvents being liquid below 100oC, or even at room temperature (room temperature ionic liquids, RTIL's). They are nonflammable, have low vapor pressure, high ionic
conductivity and excellent chemical and thermal stability over a large temperature range. IL’s can be synthesized in a wide range of structures and many IL’s have even been developed for specific applications and processes. One such group of IL’s is brönsted
acid - base IL’s. This system operates such that the brönsted base functions as an acceptor of protons of the brönsted acids and thus creates a grotthus mechanism based proton conduction path in the ionic liquids. One of the application of these brönsted acid –
base IL’s which are used in various morphologies and configurations includes membranes for fuel cells, the simplest approach being a supported liquid membrane. Other applications for these brönsted acid – base IL’s include sensors, electrochemical capacitor, electrochromic windows etc. IL’s can also be used as a liquid in a membrane contactor, where the liquid viscosity is an important factor which can be controlled by changing temperature and they can be functionalized to incorporate unsaturated carbon–carbon bonds that can be used to form polymers.