Modeling of Conductivity of Lithium Salt in Electrolytes for Lithium-Ion Batteries

Abstract

The lithium ion battery is the most competitive power source for electric vehicles needed in the future, thus attracting extensive interest. The performance of a lithium ion battery depends to a great extent on the conductivity of electrolyte solution, because the conductivity of electrolyte solution is related to transport process and play an important role in field of lithium batteries as knowledge of the conductivity is necessary for the design of Li cells [1]. The conductivity provides also useful insights on ion solvation and association. We present in this work a comparative study on experimental values of conductivity of several formulated electrolytes (pure solvents, binary or ternary systems involving a lithium salt) with calculated values by modelling. At first, by using different well-known equations based on Stock-Einstein, Jones-Dole and Bjerrum theories and of the solvent-solvent and solvent-salt interactions a model of conductivity ionic had been developed. The relative permittivity values of the electrolytes as well as the B- coefficients of the Jones-Dole equation for the relative viscosity of concentrated electrolyte solutions have been determined as a function of the temperature. Finally, the calculated values were then compared with experimental data of conductivity to evaluate the predictive capability of the model. Excellent agreements were obtained between calculations and experimental data electrolytes as a function of temperature with deviations up to (4 and 10) %. Results obtained by modeling during this work will guide the formulation of safer electrolytes able to improve the performances of lithium-ion batteries of lithium-ion batteries and the lifetime [1] F.Blanchard, B. Carré, P.Willmann, D. Lemordant, Journal of power sources. 109 (2002) 203-213.