Maximum Electrical Conductivity of Associated Lithium Salts in Solvents for Lithium–Air Batteries

Abstract

The choice of optimal electrolytes is crucial for improving the electrochemical performance of a lithium air battery because it determines the morphology of the discharge products in the cathode and the conductivity of the electrolyte. We have critically analyzed an important aspect related to the behavior of highly associated electrolytes, as those used in lithium−air batteries: the prediction of the concentration of maximum conductivity. Lithium triflate and lithium bis(trifluoromethyl sulfonyl)imide in glymes of low dielectric constant (1,2-di-methoxyethane and bis(2-methoxy-ethyl)ether) were used as a model of electrolytes exhibiting strong ionic clustering. The viscosity and lithium transference number of all the electrolytes were measured, and it was found that the correlation between the concentration of maximum conductivity and coefficient that describes the high-order dependence of the electrolyte viscosity with the concentration is no longer valid in these electrolytes because of the failure of Walden's rule, although a qualitative correlation with the salts' association constant was observed.

Glyme-based electrolytes: suitable solutions for next-generation lithium batteries

“…We remark herein that viscosity and Li + transference number measurements on solutions using either G 1 or G 2 and either LiTf or LiTFSI have suggested a failure of the Walden's rule, in spite of a qualitative correlation with the association constant of the salts. 126 The electrolyte composition may affect crucial parameters for applications in a Li-O 2 battery using a carbon-cloth GDL, such as the conductivity, viscosity, contact angle, and decomposition temperature. Among various formulations, the G 4 -LiTFSI was often selected as the electrolyte of choice due to its suitable properties for use in the open metal-oxygen cell design.…”

“…We remark herein that viscosity and Li + transference number measurements on solutions using either G 1 or G 2 and either LiTf or LiTFSI suggested a failure of Walden's rule, in spite of a qualitative correlation with the association constant of the salts. 126…”

“…Notably, this system could store even more energy than the Li–S cell and has been suggested as a possible battery for future applications. 105–130 In this review, we discuss with chronological details various developments in the research on glyme-based electrolytes for lithium batteries, which are summarized in the scheme in Fig. 1 (panel a).…”

Potential solvents and electrolytes for energy storage applications: A Review

“…Horwitz G. et al [30] fundamentally analysed a significant viewpoint identified with the conduct of profoundly related electrolytes, as those utilized in lithium−air batteries. As a model of electrolytes with solid ionic grouping, lithium triflate and lithium bis(trifluoromethylsulfonyl)imide were used in monoglyme and diglyme.…”

Operational Strategies to Improve the Performance and Long‐Term Cyclability of Intermediate Temperature Sodium‐Sulfur Batteries

“…[45,46] Thus, it was restated to a comparable specific conductivity quantity, called molar conductivity ( Figure 3). [47,48] The value of molar conductivity is equivalent to the conductance caused by all the mobile ionic charge-carriers in the solution reduced to 1 M concentration, but for the same volume (cm 3 ) in-between the electrodes (area 1 cm 2 and 1 cm apart).…”