Grain Selection Growth of Soft Metal in Electrochemical Processes

TL;DR

This paper develops a thermodynamic and phase-field model to understand and control grain selection growth in soft metals like lithium and sodium during electrochemical processes, impacting battery performance and safety.

Contribution

It introduces a comprehensive framework combining thermodynamics and phase-field modeling to analyze grain growth influenced by surface energy and atomic mobility in soft metals.

Findings

Grain growth differences are due to surface energy and diffusion barrier anisotropy.

Kinetic limitations in Li metal batteries are linked to surface energy anisotropy under stress.

An amorphous LixSi1-x seed layer enhances critical current density in solid-state batteries.

Abstract

Soft metals like lithium and sodium play a critical role in battery technology owing to their high energy density. Texture formation by grain selection growth of soft metals during electrochemical processes is a crucial factor affecting power and safety. Developing a framework to understand and control grain growth is a multifaceted challenge. Here, a general thermodynamic theory and phase-field model are formulated to study grain selection growth of soft metals. Our study focuses on the interplay between surface energy and atomic mobility-related intrinsic strain energy in grain selection growth. Differences in grain selection growth arise from the anisotropy in surface energy and diffusion barrier of soft metal atoms. Our findings highlight the kinetic limitations of solid-state Li metal batteries, which originate from load stress-induced surface energy anisotropy. These insights lead to the development of an amorphous LixSi1-x (0.50<x<0.79) seed layer, improving the critical current density at room temperature for anode-free Li solid-state batteries through the control of grain selection growth.