Effect of temperature on the kinetics of electrochemical insertion of Li-ions into a graphite electrode studied by kinetic Monte Carlo

E.M. GAVILÁN; M. P. MERCER; O. A. PINTO; O. A. OVIEDO; BARRACO, D.E.; H. E. HOSTER; E. P. M. LEIVA

JOURNAL OF THE ELECTROCHEMICAL SOCIETY

ELECTROCHEMICAL SOC INC

Año: 2019

0013-4651

To better understand the operation of lithium ion batteries at different temperatures, there is a need to model the physical processes underpinning the kinetics of the staging transitions in graphite. Here, the effect of temperature on the kinetics of electrochemical insertion/removal of lithium in graphite is analyzed by kinetic Monte Carlo methods. The response of the system under the application of different electrochemical techniques is simulated and compared with experimental results. Voltammograms at a given sweep rate show how the behavior of the system becomes closer to equilibrium as temperature increases, resembling experimental data. Chronoamperometric profiles were predicted on the basis of theoretical calculations, with the finding that current shows a different qualitative behavior at different temperatures, especially in the Cottrell representation peaks. Although results at room temperature are in good agreement with experiment, trends at elevated temperature have not been described in experimental or theoretical works yet. Exchange current densities for different degrees of lithium intercalation at different temperatures are predicted using potentiostatic simulations. The dependence of the exchange current on the electrolyte composition is also simulated. The influence of temperature on the diffusion phenomena is also addressed and the results are compared with experimental data from the literature.