Effect of fine particle content in silicon alloy powders on slurry dispersion, electrode uniformity, and protrusion formation

초록

Silicon-metal alloy (Si-alloy) anodes are widely recognized as promising candidates for high-energy lithium-ion batteries (LIBs) due to their high capacity and improved structural stability. While the chemical composition of Si-alloys has been extensively studied, the influence of powder morphology, particularly the fine particle content, on slurry behavior and electrode integrity remains insufficiently understood. This study focuses on Si-alloy powders with identical compositions but different fine particle contents, fabricated by controlling milling conditions. Although both powders share the same crystalline phases, they exhibit distinct particle size distributions, which strongly affect slurry rheology, binder dispersion, and electrode microstructure. The powder with higher fine content shows stronger interparticle repulsion and greater shear stress, which leads to inhomogeneous binder distribution and the formation of surface protrusions and cracks during electrode fabrication. In contrast, electrodes made with the low-fine-content powder maintain more uniform structures and demonstrate better mechanical cohesion and consistent electrochemical performance. These findings highlight the critical role of particle size control as a design parameter in Si-alloy-based anode materials. The results offer practical guidance for optimizing slurry formation and electrode processing, contributing to the scalable implementation of silicon-graphite composite anodes in commercial LIB manufacturing.

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