Thermodynamic Factor for Facilitating Homogeneous Dendrite Growth in Alkali Metal Batteries

摘要

This study suggests a critical factor that regulates (in)homogeneous growthbased on an in-depth understanding of three alkali metal ((AM): Li,Na, and K) models using unified-multiscale atomistic calculations. Theimportance of AM disordered phases as a transition state is covered witha thermodynamic energy dataset using density functional theory (DFT)calculations, which indicates that the disordered-phase energy level(DPEL) plays a decisive role in controlling the degree of non-homogeneityduring electrochemical deposition. Using the DFT-assisted machinelearning method, the DPEL-related cohesive energy is investigatedto understand in depth the energy level of disordered phase. Reliablemolecular dynamics (MD) simulations systematically compare AM growthduring charging. The results illustrate severely fluctuating morphologiesincluding sharp tips in Li metal, whereas Na and K metals showed smoothsurfaces. Finally, the transition state thermodynamics are explored usingcross-sectional AM growth models. Metallic Li is preferentially adsorbedon its crystalline phase rather than on grain boundaries comprisingdisordered phases, resulting in severe dendritic Li growth. However,these characteristics are rarely observed for K metal during the entiredeposition process. Based on the growth mechanisms of the three typesof AM models, DPEL poses a potentially universal design strategy forfacilitating homogeneous lithium-metal dendrite growth.