Understanding Charge-Transfer and Mass-Transfer Effects on Dendrite Growth and Fast Charging of Li Metal Battery

Abstract

Lithium (Li) metal is facing the challenge of poor cyclic performance and potential safety hazards caused by Li dendrites growth. Herein, the role of charge-transfer and mass-transfer process on dendrite growth and fast charging is illustrated. The effects of charge-transfer coefficient, applied current density, concave-convex structure, and properties of artificial solid electrolyte interphase (SEI) on guiding the Li dendrite growth are investigated via an electrochemical multiphysics model. The charge-transfer coefficient is meaningful for regulating the redox rate of electrode surface. Large applied current density and high ion conductivity of artificial SEI influence the distribution of local deposition rate significantly. Different deposition behaviors are found on concave and convex Li metal surfaces. The convex surface is sensitive than concave surface and is easy to generate Li dendrites under the conditions of high applied current density and high ion conductivity. Moreover, the experimental results can well reflect the influence of dendrite growth and dead Li on the capacity. This study not only provides an essential perspective on designing the artificial SEI for resolving the harmful dendrite issues but also boosts the practical applicability of Li metal battery.