Supramolecular Regulation of Anions Enhances Conductivity and Transference Number of Lithium in Liquid Electrolytes

J Am Chem Soc. 2018 Sep 5;140(35):10932-10936. doi: 10.1021/jacs.8b05915. Epub 2018 Jul 17.

Abstract

Achieving high ionic conductivity in lithium-ion battery (LIB) electrolytes requires dissociation of Li-salts; however, though the generation of free Li+ from salt dissociation is advantageous, the presence of freely diffusing anions may reduce the Li+ transference number. The use of supramolecular anion recognition to regulate and modify ion-pairing and diffusion of anions in battery electrolytes is yet to be deeply understood. Herein, we demonstrate that addition of a selective and strong PF6--binding macrocycle to a solution of LiPF6 in low dielectric media leads to enhanced ion pair dissociation and an increased Li+ transference number. This work provides a well-defined model system to study the effects of anion binding in battery electrolytes.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't