A Study of the Physical Properties of Li-Ion Battery Electrolytes Containing Esters

By E. Logan, E. Tonita, K. Gering, Jing Li, Xiaowei Ma, L. Y. Beaulieu, J. Dahn. 2018

218 citations recorded by the source corpus.

Adding esters as co-solvents to Li-ion battery electrolytes can improve low-temperature performance and rate capability of cells. This work uses viscosity and electrolytic conductivity measurements to evaluate electrolytes containing various ester co-solvents, and their suitability for use in high-rate applications is probed. Among the esters studied, methyl acetate (MA) outperforms other esters in its impact on the conductivity and viscosity of the electrolyte. Therefore, viscosity and conductivity were measured as a function of temperature and LiPF6 concentration for electrolytes ethylene carbonate (EC): linear carbonate: MA in the ratio 30:(70-x):x, where linear carbonate = {ethyl methyl carbonate (EMC), dimethyl carbonate (DMC)}, and x = {0, 10, 20, 30}. Adding MA leads to an increase in conductivity and decrease in viscosity over all conditions. Calculations of electrolyte properties from a model based on a statistical-mechanical framework, the Advanced Electrolyte Model (AEM), are compared to all measurements and excellent agreement is found. All electrolytes studied roughly agree with a Stokes' Law model of conductivity. A Walden analysis shows that the ionicity of the electrolyte is not significantly impacted by either MA content or LiPF6 concentration. Li[Ni0.5Mn0.3Co0.2]O2/graphite cells containing MA were cycled at charging rates up to 2C and showed improved cycling performance.

Subfields: Automotive Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/37ecf30ec88264ba5d61f3fd053019ae80efd4e9

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Citations in the corpus

A Review on Temperature-Dependent Electrochemical Properties, Aging, and Performance of Lithium-Ion Cells (2020, background): “[60] studied the effect of adding methyl acetate (MA) as an ester co-solvent on the low-temperature performance and rate capability of cells.”
Lithium Plating Mechanism, Detection, and Mitigation in Lithium-Ion Batteries (2021, background): “[219] with permission of Electrochemical Society).”
Rethinking How External Pressure Can Suppress Dendrites in Lithium Metal Batteries (2019, background): “6 viscosity of 2 cp[57], and a pore diameter of 0.”