Open AccessInsights into the Transport and Thermodynamic Properties of a Bis(fluorosulfonyl)imide-Based Ionic Liquid Electrolyte for Battery Applications
Author(s) -
Jack Fawdon,
Gregory J. Rees,
Fabio La Mantia,
Mauro Pasta
Publication year - 2022
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.1c04246
Subject(s) - electrolyte , ionic liquid , imide , electrochemistry , lithium (medication) , diffusion , chemistry , ionic bonding , ionic conductivity , ion , inorganic chemistry , chemical engineering , materials science , thermodynamics , organic chemistry , electrode , medicine , physics , engineering , endocrinology , catalysis
Ionic liquid electrolytes (ILEs) have become popular in various advanced Li-ion battery chemistries because of their high electrochemical and thermal stability and low volatility. However, because of their relatively high viscosity and poor Li + diffusion, it is thought large concentration gradients form, reducing their rate capability. Herein, we utilize operando Raman microspectroscopy to visualize ILE concentration gradients for the first time. Specifically, using lithium bis(fluorosulfonyl)imide (LiFSI) in N -propyl- N -methylpyrrolidinium FSI, its "apparent" diffusion coefficient, lithium transference number, thermodynamic factor, ionic conductivity, and resistance of charge transfer against lithium metal were isolated. Furthermore, the analysis of these concentration gradients led to insights into the bulk structure of ILEs, which we propose are composed of large, ordered aggregates.