From Atoms to Devices - Multiscale Modeling of Interfaces in Solid-State Batteries

About

Dr. Yue Qi, Joan Wernig Sorensen Professor of Engineering at Brown University will present a seminar titled "From Atoms to Devices - Multiscale Modeling of Interfaces in Solid-State Batteries" to the interested faculty and students at Discovery Park.

Abstract

Solid-state batteries promise high energy density and improved safety, yet the challenge often lies at the interfaces, where ion transport, charge transfer, chemical reactions, and mechanical deformation are strongly coupled. In this talk, I will discuss how multiscale Multiphysics modeling can connect atomic-scale interfacial processes to device-level behavior, focusing on three questions that limit solid-state batteries. First, to probe interface resistance, we combine density functional theory (DFT), electrochemical thermodynamics, and continuum modeling to describe how electrons and ionic defects redistribute when two materials are brought into electrochemical equilibrium. A recent multi-ion space-charge-layer model shows that Li defects, oxygen defects, and electrons can all contribute to interfacial charge transfer, producing state-of-charge-dependent potential drops and band bending. These predictions are connected with experimental probes of local potentials and defect distributions, providing a framework for understanding intrinsic interface resistance. Second, we predict dynamic interface evolution during Li stripping, which couples interfacial adhesion, atomic hopping, Li metal creep, surface roughness, and stack pressure across multiple length and time scales. Rather than attempting to track every evolving void, we integrate DFT, kinetic Monte Carlo, and continuum mechanics to predict the steady-state contact fraction. The results reveal how interface chemistry dominates contact stability at low pressure, while stack pressure becomes increasingly important at higher loads, and suggest chemical strategies for stabilizing stripping interfaces. Finally, we revisit our early prediction that internal defects such as grain boundaries and crack surfaces are not only mechanical defects but can also possess distinct electronic structures that promote electron localization and internal Li nucleation. This coupling between electronic leakage and fracture provides a basis for understanding different Li-penetration modes and suggests complementary design strategies: engineering grain-boundary chemistry to suppress internal reduction and modifying near-surface composition and stress to improve fracture resistance and defect tolerance. Together, these studies illustrate how multiscale modeling can transform interfacial mechanisms, from electronic structure and point defects to contact mechanics and fracture, into practical design variables for solid-state batteries.

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