Pore-scale modeling of capillary-driven binder migration during battery electrode drying

2026-03-19

AI Summary

This study addresses the non-uniform migration of binders in hard carbon electrodes for sodium-ion batteries during drying, driven by capillary forces, which compromises both mechanical integrity and electrochemical performance. For the first time, a continuum multiphase flow model explicitly couples capillary transport with realistic microstructural effects at the pore scale. By integrating digitally reconstructed microstructures of hard carbon electrodes, the model enables physically consistent, spatially resolved predictions of binder redistribution. Simulations reveal that smaller particle sizes promote more uniform binder distribution, whereas higher evaporation rates and elevated surface tension exacerbate concentration gradients. This work underscores the critical importance of explicitly modeling capillary phenomena to rationally optimize electrode drying protocols.

Technology Category

• Machine Learning: Learning with Manifolds
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Planning, Routing, and Scheduling: Model-Based Reasoning

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Systems and Infrastructure for Web, Mobile and WoT: Sustainability and carbon-aware systems for Web, mobile, and WoT
• Web Mining and Content Analysis: Models for Web evolution

Abstract

Sodium-ion batteries employing hard carbon electrodes are considered a drop-in technology for lithium-ion batteries. Electrode drying is a critical manufacturing step, as binder migration during pore emptying impacts the mechanical integrity and electrical performance of the electrode. Existing modeling approaches predominantly rely on the film shrinkage phase in a one dimensional way or neglect the capillary transport, resulting in a lack of physically consistent microstructure resolved predictions of binder migration. In this work, a spatially resolved pore scale continuum model is extended to explicitly describe capillary driven binder transport during pore emptying. The model is applied to hard carbon microstructures with varying mean particle diameters. The simulations reveal that smaller particle sizes lead to a more homogeneous binder distribution, whereas higher evaporation rates and increased surface tension promote stronger binder gradients. Variations in solvent viscosity show only a minor influence on binder migration, as long as no hydrophilic or hydrophobic behavior is present. Finally, the simulations demonstrate that an explicit description of capillary transport and microstructural effects is essential for accurately predicting binder migration and provides a basis for the targeted optimization of electrode drying processes.

Problem

• binder migration
• capillary transport
• electrode drying
• pore-scale modeling
• sodium-ion batteries

Innovation

• pore-scale modeling
• capillary-driven transport
• binder migration
• electrode drying
• microstructure-resolved simulation