中文版 | English

News

Ionic association analysis of LiTDI, LiFSI and LiPF6 in EC/DMC for better Li-ion battery performance

New lithium salts such as lithium bis(fluorosulfonyl)imide (LiFSI) and lithium 4,5-dicyano-2-(trifluoromethyl)imidazole-1-ide (LiTDI) are now challenging lithium hexafluorophosphate (LiPF6), the most used electrolyte salt in commercial Li-ion batteries. Thus it is now important to establish a comparison of these electrolyte components in a standard solvent mixture of ethylene carbonate and dimethyl carbonate (EC/DMC: 50/50 wt%). With this aim, transport properties, such as the ionic conductivity, viscosity and 7Li self-diffusion coefficient have been deeply investigated. Moreover, as these properties are directly linked to the nature of the interionic interactions and ion solvation, a better understanding of the structural properties of electrolytes can be obtained. The Li salt concentration has been varied over the range of 0.1 mol L−1 to 2 mol L−1 at 25 °C and the working temperature from 20 °C to 80 °C at the fixed concentration of 1 mol L−1. Experimental results were used to investigate the temperature dependence of the salt ion-pair (IP) dissociation coefficient (αD) with the help of the Walden rule and the Nernst–Einstein equation. The lithium cation effective solute radius (rLi) has been determined using the Jones–Dole–Kaminsky equation coupled to the Einstein relation for the viscosity of hard spheres in solution and the Stokes–Einstein equation. From the variations of αD and rLi with the temperature, it is inferred that in EC/DMC LiFSI forms solvent-shared ion-pairs (SIP) and that, LiTDI and LiPF6 are likely to form solvent separated ion-pairs (S2IP) or a mixture of SIP and S2IP. From the temperature dependence of αD, thermodynamic parameters such as the standard Gibbs free energy, enthalpy and entropy for the ion-pair formation are obtained. Besides being in agreement with the information provided by the variations of αD and rLi, it is concluded that the ion-pair formation process is exergonic and endothermic for the three salts in EC/DMC.


The Li-ion battery has been widely used in many applications for its high energy density and high power density. To improve the performance of Li-ion batteries, the ionic association of LiTDI, LiFSI and LiPF6 in EC/DMC has to be taken into consideration.


LiTDI, LiFSI and LiPF6 are three of the most commonly used electrolyte solvents for Li-ion batteries. LiTDI is a liquid electrolyte with a high conductivity and a low freezing point, while LiFSI and LiPF6 are solid electrolytes with higher conductivity and higher thermal stability. The ionic association between the three electrolytes in EC/DMC can lead to better Li-ion battery performance.


In order to understand the ionic association of LiTDI, LiFSI and LiPF6 in EC/DMC, we have conducted an ionic association analysis. By doing so, we can determine the optimal combination of LiTDI, LiFSI and LiPF6 for the best Li-ion battery performance. The analysis includes the determination of the ionic association constants, the thermodynamic parameters and the electrical conductivity.


Our ionic association analysis of LiTDI, LiFSI and LiPF6 in EC/DMC can help to improve the performance of Li-ion batteries. It provides us with a better understanding of the ionic association between the three electrolytes, and can be used to determine the optimal combination of LiTDI, LiFSI and LiPF6 for the best Li-ion battery performance.


Related ProductsTag Cloud Overlap

Browse by Chemical Keyword Alphabetically
CAS Index:
123456789
CAS Number Length:
5678910
Chemical Name Index:
A B C D E F G H I
J K L M N O P Q R
S T U V W X Y Z

Contact Us

Quote Now