Understanding Zn Electrodeposits Morphology in Secondary Batteries Using Phase-Field Model

Zinc (Zn) aqueous rechargeable batteries (ZBs) have shown a tremendous success in various applications due to their environmental friendliness, multi-electron capacity, high abundance, safety and low cost; however, analogous to their Li-ion battery counterparts, they suffer from the dendrite formation leading to decrease in capacity and eventual failure. Despite many studies reporting a good performance and partial dendrites suppression, there have been little theoretical systematic studies of Zn electrodeposits morphology analysis in ZBs. In the current work, we present the results from phase-field modeling (PFM) of Zn electrodeposition at different current densities. Different Zn morphologies, such as boulders, mossy and dendritic shape are modeled. The computational model predicts two-dimensional distribution of Zn electrodeposits, Zn2+ ions concentration, electrostatic potential, stress and equivalent plastic strain. It was found that the stress has a major influence on the electrodeposition, and vice versa the Zn electrodeposits growth is found to affect the stress distribution significantly. The plastic yielding occurs preferentially at the node of the boulders and through the filaments and mossy structures. The results also provide a basis for development and design of novel strategies against unwanted Zn dendrites formation.