Symposium ET03: Application of Nanoscale Phenomena and Materials to Practical Electrochemical Energy Storage and Conversion

Matthew Gebbie, Stanford University

Ionic Liquids and Dilute Electrolytes—The Surprising Connection

 Written by Tianyu Liu

Do you think that a cup of concentrated salt solution behaves microscopically the same as a cup of water with little salt? In terms of the ionic conductivity, the answer of Matthew Gebbie from Stanford University is yes. He investigated the origin of the ultralow ionic conductivities of ionic liquids, that is, fluids composed of only cations and anions. With the help of an in situ electrochemical spectroscopy, Gebbie observed that more than 99% of the cations and anions in ionic liquids formed neutral pairs that are not ionically conductive. This characteristic of ionic liquids resembles that of diluted aqueous solutions containing a limited number of mobile ions. Due to the small population of moveable ions, ionic liquids having 100% ions exhibit comparably low ionic conductivity to diluted solutions with nearly no ions.