Effect of Temperature on The Kinetics of Electrochemical Insertion of Li-Ions into a Graphite Electrode Studied by Kinetic Monte Carlo

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

Journal of The Electrochemical Society

IOP

Año: 2020 vol. 167

The effect of temperature on the kinetics of electrochemical insertion/removal of lithium in graphite is analyzed by kinetic MonteCarlo methods. Different electrochemical techniques are simulated at different temperatures and responses are compared withexperimental results. Simulated voltammograms show, similarly to experiment, how the behavior of the system becomes closer toequilibrium as temperature increases. Calculated chronoamperometric profiles show a different qualitative behavior in the current atdifferent temperatures, especially in the Cottrell representation peaks, explained in terms of the relative importance of diffusive versuscharge transfer processes at different temperatures. Results at room temperature are in good agreement with experiment, and wefurther evaluate trends at elevated temperature that have not yet been described in experimental or theoretical works. Exchange currentdensities for different degrees of lithium intercalation at different temperatures are predicted using potentiostatic simulations, showingan Arrhenius-type relationship. The dependence of the exchange current on electrolyte composition is simulated by investigatingthe effect of different activation energy barriers at different temperatures. The influence of temperature on diffusion coefficients as afunction of lithiation fraction in graphite is simulated and related to Arrhenius plots, explaining the experimentally observed changesin diffusion phenomena with lithium composition and temperature.