Bimodal Electrode Microstructure Engineering for High-Rate Polarization Suppression in Lithium-Ion Batteries

High-speed charging and high-power lithium-ion batteries require optimized electrode microstructure. While active material properties are studied, the impact of particle size distribution and spatial arrangement at the electrode level remains less explored. This study presents a novel strategy using a bimodal particle size distribution by precisely mixing large and small LiNi0.8Co0.15Mn0.05O2 particles to engineer electrode architecture. We demonstrate that monodisperse systems exhibit compaction-porosity trade-offs. In contrast, our optimized bimodal electrode achieves a balanced microstructure with improved interparticle connectivity and controlled porosity. This yields superior electrochemical performance, including enhanced rate capability, high capacity retention, low charge transfer resistance, and stable electrochemical surface area, which is validated by direct current-superimposed electrochemical impedance spectroscopy. Peukert’s constant analysis further supports high-rate capability. Our findings highlight the critical role of electrode- level particle arrangement, offering a practical bimodal engineering methodology for high-performance lithium-ion battery design for fast charging and high-power applications.