Toward Establishing the Principles of Electronic Structure Modeling of Battery Interfaces

Electronic structure modeling of explicit interfaces in high energy density batteries can potentially provide conceptual advances in the understanding of the voltage–function relations of very complex battery interfaces, which govern battery stability, charging rate, and lifetime. However, there are substantial differences of opinion in this modeling community on crucial, fundamental principles, such as whether surface film formation is governed by kinetics or thermodynamics, the ways to define voltages in Density Functional Theory (DFT) battery interface calculations, whether overpotentials exist in such calculations, and what the interpretation of DFT-based ab initio molecular dynamics computational experiments should be. Here we propose a forward-looking set of guiding principles on these subjects. We also highlight the need to model multiple reaction steps and to model multilayer surface films instead of pristine electrode surfaces. We illustrate the above principles using models and calculations from our work on batteries with liquid electrolytes, suggest that related principles are also relevant to the interfaces of all-solid-state batteries, and aim to generate discussions among theorists and experimentalists on these crucial topics associated with battery interface modeling.