Public Abstract

DE-SC0001780: SISGR: Physical Chemistry of Reaction Dynamics in Ionic Liquids

Award Status: Inactive

Institution: Rutgers, The State University of New Jersey, New Brunswick, NJ
UEI: M1LVPE5GLSD9
DUNS: 001912864

Most Recent Award Date: 06/20/2017
Number of Support Periods: 7
PM: Fecko, Christopher

Current Budget Period: 03/15/2016 - 03/14/2018
Current Project Period: 03/15/2016 - 03/14/2018
PI: Castner, Edward

Supplement Budget Period: N/A

Public Abstract

This project is focused on the physical chemistry of ionic liquids (ILs), particularly those aspects that relate to their performance in systems for the collection, storage and utilization of energy. ILs are liquid salts; they consist solely of combinations of organic and inorganic molecular anions and cations that have low melting temperatures because of the divergent shapes and charge distributions of the ions. Because of their nature, ILs differ from conventional liquids in several ways, and those differences make them useful in a wide range of energy applications. The objective of the project is to understand how ILs affect fundamental processes necessary for energy capture and storage, which include the absorption of energy from light and its conversion into chemical energy. We examine photoinduced charge transfer, photocleavage and photoionization reactions in ILs, the response of ILs to charge redistribution within molecules, the impact of the IL environment on the properties of solute molecules, the transport of solute molecules in ILs, and the diffusion of the constituent ions of the IL. Because of the way the ions come together, ILs have structural organization on the molecular scale that strongly affects all of the phenomena we study, and understanding IL structure is an important part of our work. In particular, recent work from the group has experimentally demonstrated a vast difference in the speeds of diffusion in ILs of small neutral molecules (faster) versus small charged ones (slower), and our molecular dynamics simulations showed that this is caused by the difference in interactions of the charged and uncharged solutes with the molecular-scale structure of the IL. Our team includes five investigators with diverse and complementary specializations. Our methods include a full set of instruments for preparing ILs and characterizing their physical properties, ultrafast transient absorption, emission, Raman and time-resolved infrared detection techniques, pulse radiolysis, high-energy X-ray scattering, NMR diffusion measurements, and high-performance computational studies of electronic structure and molecular dynamics. The work that has taken place under this project has already had a significant impact on the IL research community, and prominent IL researchers collaborate with us to mutual benefit. Exciting progress was made during the prior grant period with a landmark series of articles that explain the broad distribution of solvent relaxation times in ILs. Significant progress has been made in comprehending the intrinsic structure of ILs, and in the coming period we will apply the knowledge we gained to better understand how structure affects transport and reactivity in them. A growing facet of our research is the effect of adding cosolvents on IL structure and its impact on transport and reactivity in ILs. This work will benefit the Department of Energy’s mission by providing the fundamental information needed to enable the effective use of ILs in advanced and durable systems for the collection and storage of energy, with emphasis on light-driven processes for charge separation and transport.

This project is focused on the physical chemistry of ionic liquids (ILs), particularly those aspects that relate to their performance in systems for the collection, storage and utilization of energy. ILs are liquid salts; they consist solely of combinations of organic and inorganic molecular anions and cations that have low melting temperatures because of the divergent shapes and charge distributions of the ions. Because of their nature, ILs differ from conventional liquids in several ways, and those differences make them useful in a wide range of energy applications.

The objective of the project is to understand how ILs affect fundamental processes necessary for energy capture and storage, which include the absorption of energy from light and its conversion into chemical energy. We examine photoinduced charge transfer, photocleavage and photoionization reactions in ILs, the response of ILs to charge redistribution within molecules, the impact of the IL environment on the properties of solute molecules, the transport of solute molecules in ILs, and the diffusion of the constituent ions of the IL. Because of the way the ions come together, ILs have structural organization on the molecular scale that strongly affects all of the phenomena we study, and understanding IL structure is an important part of our work. In particular, recent work from the group has experimentally demonstrated a vast difference in the speeds of diffusion in ILs of small neutral molecules (faster) versus small charged ones (slower), and our molecular dynamics simulations showed that this is caused by the difference in interactions of the charged and uncharged solutes with the molecular-scale structure of the IL.

Our team includes five investigators with diverse and complementary specializations. Our methods include a full set of instruments for preparing ILs and characterizing their physical properties, ultrafast transient absorption, emission, Raman and time-resolved infrared detection techniques, pulse radiolysis, high-energy X-ray scattering, NMR diffusion measurements, and high-performance computational studies of electronic structure and molecular dynamics.

The work that has taken place under this project has already had a significant impact on the IL research community, and prominent IL researchers collaborate with us to mutual benefit. Exciting progress was made during the prior grant period with a landmark series of articles that explain the broad distribution of solvent relaxation times in ILs. Significant progress has been made in comprehending the intrinsic structure of ILs, and in the coming period we will apply the knowledge we gained to better understand how structure affects transport and reactivity in them. A growing facet of our research is the effect of adding cosolvents on IL structure and its impact on transport and reactivity in ILs.

This work will benefit the Department of Energy’s mission by providing the fundamental information needed to enable the effective use of ILs in advanced and durable systems for the collection and storage of energy, with emphasis on light-driven processes for charge separation and transport.