Simulation of galvanostatic growth of polycrystalline Li deposits in rechargeable Li batteries

This brief communication is a preliminary attempt to apply models developed for electrochemical deposition of metals from aqueous solutions or molten salts (passivation-free condition), to the more complicated case of Li deposition from nonaqueous solutions. The model systems chosen were lithium electrodes in rechargeable, commercial Li (metal)-Li_xMnO₂ AA batteries cycled at different high charging rates. Under these conditions, the Li deposits formed are hemispherical in shape. The passivation of the active metal in solution is not efficient, and the active metal deposited reacts with the solution components at high rate, proportional to the surface of the grains that are exposed to the solution. Our measurements and calculations showed that the number of Li grains deposited per unit area of electrode increases with the current density applied, as predicted previously by models developed for the simpler electrodeposition processes.