Modeling the Influence of Silicon Content on Electrochemical Performance of Silicon-Graphite Blended Electrodes Considering Voltage Hysteresis

Abstract Silicon, with its high specific capacity, is a highly promising material for lithium-ion battery anodes. To enhance durability, it is commonly combined with graphite in composite anodes. Despite this, the electrochemical dynamics between silicon and graphite are not yet fully understood. Modeling serves as an important tool for analyzing and improving batteries, but current models lack comprehensive representation of the coupled electrochemical and structural behavior of silicon-graphite blended electrodes. Herein, we present a comprehensive model for blended Si/Gr electrodes that incorporates the distinct properties and kinetics of each material. Our approach accounts for the dependence of electrode thickness and solid volume fraction on silicon content. Additionally, a memory-hysteresis variable is introduced to represent accurately silicon’s path-dependent voltage hysteresis. Our model reveals how silicon content influences the lithiation and delithiation dynamics, demonstrating that increased silicon enhances specific capacity. Our model predictions agree well with experimental data and provide insights into how silicon content affects electrolyte distribution and electrode thickness.