Effect of ethylene carbonate concentration on the conductivity of carbonate-based electrolytes with LiPF6 for Li-ion batteries

Abstract

A four-probe pouch-type cell was used to study the influence of carbonate-based electrolyte composition on the total conductivity of polyolefin separator impregnated with electrolyte through the electrochemical impedance spectroscopy. A frequency dispersion of separator with electrolyte is found to be dependent on the volume ratio of ethylene carbonate and ethyl methyl carbonate in an electrolyte solution. The origin of high-and lowfrequency relaxation processes obtained from the impedance spectra is discussed. A correlation between the direct current resistance of separator with electrolyte and dissociation degree of electrolyte salt is found.

Battery Electrolytes Based on Unsaturated Ring Ionic Liquids: Conductivity and Electrochemical Stability

“…The higher values for EC have been shown for other carbonate electrolytes where the addition of EC increases conductivity until the viscosity of the solution becomes a dominating factor and causes a decrease in solution conductivity. 32,33 In Figure 1c a similar mixture was prepared to that in Figure 1b, with the addition of LiBF 4 at 1M concentration. The most conductive solution is found to be the 1E3MIm-BF 4 :1M LiBF 4 +PC mixture with a conductivity of 10.66 mS/cm at 60% ionic liquid in PC.…”

“…1.0 M LiPF 6 EC-DMC, 1.0 M LiPF 6 EC-DEC, 1.0 M LiPF 6 EC-EMC) which have reported conductivity values between 3-11 mS/cm. 6,8,32,33 The conductivity of imidazolium-TFSI ionic liquids mixed with (a) EC, (b) PC, and (c) 1 M LiTFSI salt + PC was also determined (Figure 2). The upper solubility limit of EC in the Im-TFSI series of ionic liquids occurs at 60% EC in ionic liquid which is lower than the Im-BF 4 series.…”