Lithium-ion batteries (LIBs) are widely recognized as essential energy storage systems for electronic devices and electric vehicles. Replacing the conventional graphite anode with silicon (Si) offers significant advantages, including higher energy density and specific capacity. However, silicon anodes face major challenges due to large volume expansion (~300%) during lithiation and contraction during delithiation, which generates mechanical stresses, causing surface cracking, electrode pulverization, loss of conductivity, and capacity fading. A critical manifestation of these effects is voltage hysteresis, which negatively impacts battery performance and longevity. This study presents a physics-based mathematical model to investigate the origins of voltage hysteresis in silicon-anode LIBs. Unlike prior models, this work incorporates key phenomena often overlooked in the literature: the volume expansion of silicon particles during cycling, variable electrochemical parameters, and experimental data validation. The model employs a modified Butler-Volmer equation that integrates a voltage-stress-induced term, enabling accurate prediction of the voltage gap observed during lithiation-delithiation cycles. By accounting for these critical features, the proposed model provides insights into the mechanical and electrochemical interactions responsible for hysteresis, offering guidance for optimizing silicon anode battery design. The results demonstrate that including stress-related voltage effects and dynamic electrochemical parameters improves the predictive accuracy of the model and helps explain capacity degradation mechanisms. This approach lays a foundation for designing silicon-based LIBs with enhanced cycle life and reliability, bridging the gap between theoretical modeling and experimental observations.
Johnson et al. (Mon,) studied this question.