Phase field simulation of dendrites morphology evolution in sodium metal batteries

Abstract

Sodium (Na) dendrite growth poses challenges such as short circuits and capacity loss, and the underlying mechanisms are unclear. Although the experiments of Na dendrite growth were reported, there are very few simulations that can assist in analyzing its morphology evolution mechanism. In addressing this challenge, we develop a phase-field model to explore the influence of current density, anisotropic strength, and Na-ion consumption on the evolution of Na dendrite morphology. It is found that higher current density promotes more dendrite growth and lateral branches. Anisotropy strength influences dendrite growth rates horizontally and vertically, with horizontal growth exceeding or equaling vertical growth, reducing short-circuit risks. Increased Na-ion consumption results in significant lateral branches, kinks, and pores in dendrite structures. These results offer valuable insights into mitigating the formation of erratic dendrites, holding significant implications for the advancement of Na-based batteries with high stability and safety.