Virtual Electrode Design for Lithium‐Ion Battery Cathodes

Abstract

Microstructural characteristics of lithium‐ion battery cathodes determine their performance. Thus, modern simulation tools are increasingly important for the custom design of multiphase cathodes. This work presents a new method for generating virtual, yet realistic cathode microstructures. A precondition is a 3D template of a commercial cathode, reconstructed via focused ion beam/scanning electron microscopy (FIB/SEM) tomography and appropriate algorithms. The characteristically shaped micrometer‐sized active material (AM) particles and agglomerates of nano‐sized carbon‐binder (CB) particles are individually extracted from the voxel‐based templates. Thereby, a library of roughly 1100 AM particles and 20 CB agglomerates is created. Next, a virtual cathode microstructure is predefined, and representative sets of AM particles and CB agglomerates are built. The following re‐assembly of AM particles within a predefined volume box works using dropping and rolling algorithms. Thereby, one can generate cathodes with specified characteristics, such as the volume fraction of AM, CB and pore space, particle‐size distributions, and gradients thereof. Naturally, such a virtual twin is a promising starting point for physics‐based electrochemical performance models. The workflow from the commercial cathode microstructure through to a full virtual twin will be explained and assessed for a blend cathode made of the two AMs, LiNiCoAlO2 (NCA) and LiCoO2 (LCO).

Myth and Reality of a Universal Lithium‐Ion Battery Electrode Design Optimum: A Perspective and Case Study

“…[8] 3D microstructure-resolved battery models add another level of detail as they directly utilize electrode microstructures. [53] These structures can be created virtually by microstructure generators [54,55] or can be acquired experimentally by either X-ray tomography, [56][57][58] focused ion-beam scanning electron microscopy, [59,60] or a combination of both. [61] A further analysis of these microstructures can provide quantitative information on particle size distributions, surface areas, volume fractions, and surface areas for the AM phase, carbon black-binder phase, and pore phase.…”

Recent Advances on Materials for Lithium-Ion Batteries

“…Regardless of the type of electrode, its basic constituents are the active material, the conductive material, and the polymer binder. The microstructural characteristics of lithium-ion battery electrodes also determine their performance [50].…”

An Invitation to Engage with Computational Modeling: User‐Friendly Tool for In Silico Battery Component Generation and Meshing

“…Firstly, the acquisition of a component (e. g. electrode, separator) mesostructure spatially resolved in 3D can be challenging if access to a tomogram is not available. The mesostructure will have to be computationally generated, typically using a stochastic algorithm [8–10] . “Stochastic” means here that the electrode generation will be performed through a random process that can be more or less controlled.…”