Phase-Field Investigation of Lithium Electrodeposition at Different Applied Overpotentials and Operating Temperatures

Despite the high promise, the commercialization of Li-metal-based batteries has been hampered due to the formation of dendrites that lead to mechanical instability, energy loss and eventual internal short circuits. The mechanism of dendrite formation and the strategies to suppress their growth have been studied intensively. However, the effect of applied overpotential and operating temperature on dendrite growth remains to be fully understood. Here, we elucidate the correlation of overpotential and temperature with the surface modulation during electrodeposition using phase-field simulations. We identify an optimal operating temperature of half-cell consisting of a Li metal anode and 1M LiPF6 in EC:DMC(1:1), which increases gradually as the overpotential increases. The investigation reveals that the temperature dependence identified in the simulations and experiments often disagree because they are primarily conducted in galvanostatic and potentiostatic conditions, respectively. The temperature increase under potentiostatic conditions increases the induced current while it decreases the induced overpotential under galvanostatic conditions. Therefore, the analysis and comparison of temperature-dependent characteristics must be carried out with care.