Combination of a Phase-Field Model with Nucleation Kinetics to Simulate Lithium Dendrite Growth

Abstract

The nonuniform deposition of lithium at the current collector severely hinders the development of anode-free lithium metal batteries. The morphology of such electrodeposition relies on the nucleation and growth kinetics at the electrochemical interface. Although dendritic growth remains a subject of extensive research, nucleation of lithium metal on the current collector surface remains relatively unexplored. In this article, a phase-field model will be coupled with classical nucleation theory to understand the interactions between nucleation and growth dynamics. The simulation explores the effect of overpotential on the growth morphology at slow and fast nucleation kinetics by varying the preexponential kinetic factor. At low values of the pre-exponential factor, lithium nucleation is highly dependent on the overpotential. Poor current collector surface coverage and columnar dendrite morphology are common features of such depositions. On the other hand, a high pre-exponential factor results in denser deposits and complete coverage of the current collector surface. As expected, this model shows that, in general, dendritic growth occurs at a high overpotential. This model also opens an avenue where optimization of various factors such as surface energy, additives, and operating parameters may be explored theoretically.