Conductivity variation of the liquid electrolyte, EC : PC : LiCF3SO3 with salt concentration

Abstract

It is a well known fact that liquid electrolytes inherit better conductivity values than other electrolytes such as solid electrolytes and polymer electrolytes. Basically, a liquid electrolyte consists of a salt dissolved in a solvent or a mixture of solvents. Their conductivity values therefore depend on the salt concentration as well as solvent concentration. Present study is based on the liquid electrolyte, ethylene carbonate (EC), propylene carbonate (PC) and lithium trifluoromethane sulfonate (LiCF 3 SO 3 -LiTF). Its conductivity variation with the salt concentration was investigated using AC impedance spectroscopy. The maximum conductivity observed at room temperature (RT) was 2.80 x 10 -3 S cm -1 at the salt concentration of 0.85 mol kg -1 . To explore the reasons governing the conductivity below and above that salt concentration, viscosity measurements were done using a Ostwalds viscometer. Upto the salt concentration of 0.85 mol kg -1 , conductivity increases. Hence, it can be assumed that due to the increment of charge carrier concentration with salt concentration, conductivity increases upto 0.85 mol kg -1 . After that, the effect of viscosity may dominate resulting in conductivity reduction. According to the observations, with the salt concentration, viscosity increased. The carrier mobility and hence, the conductivity decrease with viscosity. Conductivity variation with temperature of all samples followed the Vogel Tamman Fulcher (VTF) behaviour.

Ionic Liquid-Based Electrolytes for Sodium-Ion Batteries: Tuning Properties To Enhance the Electrochemical Performance of Manganese-Based Layered Oxide Cathode

“…The equations’ parameters are listed in Table , while the fitting results are reported in Figure S2. It is worth noting that the calculated activation energies are slightly lower than those reported for lithium- and sodium-based ionic liquids, but rather comparable to those of carbonate-based electrolytes …”

“…It is worth noting that the calculated activation energies are slightly lower than those reported for lithium-51 and sodium 52 -based ionic liquids, but rather comparable to those of carbonate-based electrolytes. 53 The physical−chemical properties of the electrolytes were also investigated in terms of density, as reported in Figure 5a,b. In the investigated temperature range, both the NaFSI (Figure 5a)-and the NaTFSI (Figure 5b)-based electrolytes show a decrease of density (ρ) with increasing temperature in a linear relationship well described by eq 3, in which A and B are fitting parameters.…”