Low-Temperature Conductivity Study of Multiorganic Solvent Electrolyte for Lithium-Sulfur Rechargeable Battery Application

The conductivity of an electrolyte plays a significant role in deciding the performance of any battery over a wide temperature range from -40 degrees C to 60 degrees C. In this work, the conductivity of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at a varied salt concentration range from 0.2 M to 2.0 M in a multisolvent organic electrolyte system over a wide temperature range from -40 degrees C to 60 degrees C is reported. The mixed solvents used were 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), and tetraethylene glycol dimethyl ether (TEGDME) with an equal ratio of DOL : DME : TEGDME (1 : 1 : 1 by volume). The experimental analysis performed over a wide temperature range revealed the maximum conductivity at salt concentrations ranging from 1.0 M to 1.4 M for equal molar solvents. The optimum salt concentration and maximum conductivity in a different solvent composition ratio (i.e., 3 : 2 : 1) for all the temperatures is reported herein. The temperature-dependence conductivity of the salt concentration did not fit the Arrhenius plot, but it resembled the Vogel-Tamman-Fulcher plot behavior. The present conductivity study was carried out to evaluate the overall operable temperature limit of the electrolyte used in the lithium-sulfur battery.