Multi-scale visualization of the impact of particle morphology on the fast-charging capabilities of graphite-based electrodes

The major challenge in fast-charging batteries is designing electrodes whose microstructure and composition mitigate slow lithium diffusion in active particles and limited electrolyte transport under high charging current densities, which otherwise cause concentration polarization and lithium plating. To address this issue, an electrode design methodology with greater control over particle morphology is proposed for designing graphite anodes. The workflow couples computer-aided design (CAD)-based particle design, where particles of different morphologies are generated from FIB-SEM images of artificial graphite, with 3D-resolved mesoscale electrode reconstruction to build detailed electrode microstructures. A 4D (space + time) electrochemical simulation is then applied to the reconstructed electrodes to quantify how particle morphology, packing, and pore connectivity control lithium transport, spatial lithiation, and rate capability. Using 30 × 30 × 66 μm mesoscale electrode volumes and four morphology-controlled particle populations (e.g., thin-flake particles ≈ 7.3 × 14.9 × 3.9 μm), representative simulations show an average state-of-lithiation (SOL) of ≈ 80% at 1C, with a clear through-thickness gradient and substantially increased ionic heterogeneity and capacity loss at 3C and 5C. This methodology provides actionable metrics such as SOL maps, ionic flux distribution, and rate performance, to prioritize particle morphologies and electrode microstructures that enhance cell performance during fast charging, and to guide experimental validation and scale-up for manufacturing anodes for fast charging applications.