Silicon-based anodes have received significant attention in battery research due to their high energy density. However, their thermal behavior is highly temperature-dependent, making effective thermal management essential for stable operation. One of the key aspects influencing heat generation is entropy-related heat, which itself is temperature-dependent. Understanding its contribution to overall heat generation is crucial for optimizing battery performance and safety.

This study focuses on determining the entropy coefficient of silicon, which represents one of the two major heat sources in lithium-ion batteries. The entropy coefficient was successfully measured during the delithiation process, showing a stable signal throughout. The negative entropy coefficient implies that entropy-related heat contributes to endothermic behavior during delithiation and exothermic behavior during lithiation.

To assess the relevance of entropy-related heat in practical battery operation, the obtained entropy coefficient was compared with calorimetric measurements at different temperatures. In this study, the state-of-charge (SoC)-dependent heat flux was examined. The results indicate that the difference in heat flux between low and high temperatures is significantly larger than the expected variation in heat generation calculated from the entropy coefficient. These findings suggest that resistance plays a crucial role in the thermal behavior of silicon anodes.

This study provides insights into the thermal behavior of silicon-based anodes by quantifying entropy-related heat and its influence on overall heat generation. These findings contribute to a more comprehensive understanding of heat generation mechanisms in high-energy-density silicon anodes, ultimately supporting the development of more stable and efficient lithium-ion batteries.