RUI: Investigations of hydrogen ion solvation in acidic ionic liquids - approach to high proton conductivity in ionic liquid electrolytes

Rowan University, Glassboro NJ

Investigators

Abstract

In this project funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professors Lei Yu and Timothy Vaden of the Department of Chemistry and Biochemistry at Rowan University will study the hydrogen ion ionization, solvation, transportation, and reduction in acidic ionic liquid solutions. These solutions can be used in fuel cells, which receive significant attention in chemistry and engineering as they can provide efficient, clean, and renewable energy. The application of acidic ionic liquid solutions can potentially improve the high temperature performance of the fuel cells, which is important in many applications. The research plan is well integrated with an educational plan. The project will involve undergraduate students heavily and high school students will be included in summer research activities. The principal investigators also plan to develop curricula for undergraduate students on batteries and fuel cells. Nafion, a perfluorosulfonic acid membrane, is widely used as the proton exchange membrane in fuel cells due to its excellent thermal and chemical stability, proton conductivity, and mechanical strength. However, Nafion provides high proton conductivity only when it is fully hydrated. At temperatures close to or above 100 degree, fast water evaporation results in significant reduction of proton conductivity, usually ending in cell failure. However, working at around 100 - 150 degree is desirable because higher temperature reduces catalyst poisoning and increases fuel cell efficiency. Ionic liquids with high proton conductivity could improve the high temperature performance and life span of the proton exchange membrane. In this project, hydrogen ion solvation, transportation, and reduction in ionic liquids will be studied. A series of strong and weak acids such as bis(trifluoromethanesulfonyl)imide, boric acid, sulfonic acids, carboxylic acids and their mixtures in imidazolium ionic liquids will be investigated using conductivity and viscosity measurements, vibrational spectroscopy, calorimetry, electrochemistry, and computational simulation.