(Invited) Lithium Metal Nucleation and Growth on Conductive Substrates— a Multi-Scale Understanding from Micro, Meso, to Macro-Scales

Abstract

Repetitive lithium (Li) metal deposition and stripping on conductive substrates such as copper is a critical process involved in the rechargeable Li batteries for high energy applications. Most of the time, the reversibility of this deposition and stripping process by electrochemical methods is of paramount importance for long life performance of these batteries. Solid electrolyte interphase (SEI) formation and the dendritic formation of Li whiskers are often cited as the challenges in achieving a uniform, reversible Li deposition and stripping in the process, rendering a short life duration of these batteries for practical applications. The fundamental question of how Li metal nucleates and grows on the conductive substrate has not been well understood until some recent experiments and in situ, operando observations [1,2] began to shed light on this process to offer some clues how to control the morphology of the Li deposition and stripping process.Here, a collection of experimental evidence and molecular dynamics simulations are presented to provide some insight of this seemingly straightforward process of elemental metal deposition. An explanation to peel off the mystery of the Li nucleation and growth from the atomic level to the micro (<20 nm), meso (20-100 nm), and the macro-scale (>100 nm) is offered to provide some guidance of the control needed to regulate the morphology. Success to demonstrate some highly dense and reversible Li deposition and stripping is shown.