Effect of Anisotropy on Lithium Dendrite Growth

Abstract

Lithium dendrite formation is one of the leading causes of performance degradation and safety hazards in lithium batteries. Understanding dendrite evolution and its morphology during cycling can provide the critical insight into improving battery performance and safety. Recent experimental studies with cryo-electron microscopy have revealed anisotropic morphologies of lithium metal during deposition. Lithium, being a crystalline material, exhibits different surface energies and reaction rates depending on the crystal surfaces. In this study, we apply a quantitative electrochemical phase-field model to study the impact of thermodynamic and kinetic anisotropy on lithium morphology during battery cycling. We examine scenarios involving the alignment or misalignment of lithium crystals with the applied current. We observe that due to the rapid deposition rates, lithium dendrites tend to grow along crystal directions with high kinetics, resulting in a needle-like morphology. Furthermore, we study the effect of anisotropy magnitude on morphology selection, as well as the interaction between neighboring dendrites during cycling and the effect of various factors, including the applied current and electrolyte properties. Overall, this study elucidates the relationship between lithium dendrite morphology and various factors, ultimately contributing to the development of improved batteries with enhanced performance and safety.