Residual Stress Development in Lattice Mismatched Epitaxial Thin Films via Atomic and Molecular Layer Depositions

TL;DR

This paper combines ab initio simulations and continuum models to understand residual stress development in lattice-mismatched ALD/MLD coatings on Zn anodes, revealing how chemo-mechanical stresses influence dendrite suppression.

Contribution

It introduces a multiscale approach integrating simulations and experiments to predict residual stresses in lattice-mismatched thin films on battery anodes.

Findings

Large misfit strains cause significant interfacial stresses during deposition.

Good agreement between experimental curvature measurements and theoretical predictions.

Chemical bonding influences residual stress development in thin film coatings.

Abstract

Atomic and molecular layer deposition (ALD/MLD) coatings are promising solutions for preventing dendrite formation in aqueous and non-aqueous Li/Na/Zn metal batteries. Notably, alumina and alucone coatings have emerged as highly effective against dendrite formation in Zn anodes. Despite their demonstrated efficacy, a comprehensive understanding of their chemo-mechanical impact on anodes remains elusive. In this study, we take a bottom-up framework to these coatings on Zn foils, employing an approach that integrates \textit{ab initio} simulations with continuum theories to elucidate lattice misfit and chemical bonding. We use this insight to develop a macroscopic model to predict the epitaxial residual stresses generated during thin-film deposition. Our findings reveal a robust chemical bonding between the hydroxylated Zn surface and the thin film. This, in turn, generates large misfit strains that result in significant interfacial stresses during deposition. These results are then compared to experiments by measuring the curvature of the coated thin films, finding good agreement between experiments and theory. This novel understanding sheds light on the fundamental mechanisms underpinning the development of chemo-mechanical stresses in thin films, which impact dendrite suppression in anodes, offering valuable insights for the design of new coatings.