Rheological modeling and optimization of Si-SWCNT anode slurry coatings for enhanced capacity and stability in lithium-ion batteries

Abstract

This study explores silicon (Si) as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity, but its significant volume expansion during lithiation causes mechanical degradation and capacity loss. While nano-sized Si particles help reduce this expansion, they are prone to aggregation and increased side reactions. To address these issues, we incorporated single-walled carbon nanotubes (SWCNTs) to enhance electrical conductivity and provide mechanical reinforcement. SWCNTs form a wrapping effect around Si particles, alleviating volume expansion and maintaining electrode integrity. By optimizing the combination of nano- and micro-sized Si particles, we achieved high capacity and improved cycling stability. A microrheological model was used to predict the rheological behavior of Si-SWCNT anode slurries, and enhanced surface adhesion on the electrode was observed, driven by increased capillary pressure and surface tension forces.