Iodine added to iodide-based ionic liquids leads to extraordinarily efficient charge transport, vastly exceeding that expected for such viscous systems. Using terahertz time-domain spectroscopy, in conjunction with dc conductivity, diffusivity and viscosity measurements we unravel the conductivity pathways in 1-methyl-3-propylimidazolium iodide melts. This study presents evidence of the Grotthuss mechanism as a significant contributor to the conductivity, and provides new insights into ion pairing processes as well as the formation of polyiodides. The terahertz and transport results are reunited in a model providing a quantitative description of the conduction by physical diffusion and the Grotthuss bond-exchange process. These novel results are important for the fundamental understanding of conduction in molten salts and for applications where ionic liquids are used as charge-transporting media such as in batteries and dye-sensitized solar cells.
@article{arxiv.1011.2182,
title = {Extraordinarily Efficient Conduction in a Redox-Active Ionic Liquid},
author = {Verner K. Thorsmølle and Guido Rothenberger and Daniel Topgaard and Jan C. Brauer and Dai-Bin Kuang and Shaik M. Zakeeruddin and Björn Lindman and Michael Grätzel and Jacques-E. Moser},
journal= {arXiv preprint arXiv:1011.2182},
year = {2016}
}
Comments
Article: 17 pages, 3 figures. Supplementary information: 14 pages, 6 figures. Table of contents figure: 1 page. Accepted for publication in ChemPhysChem