Tracing the Origins of Calendar Aging in Si-Containing Lithium-Ion Batteries

This study thoroughly investigates the calendar aging of silicon-containing batteries from the cell scale to the phase scale through comprehensive technical characterizations. Under the same areal capacity, the addition of 10 wt% Si facilitates anode light-weighting but results in a fourfold reduction in overall battery lifespan. After 72 hours of storage at room temperature, the cycle life decreases by 3-4 times. Calendar aging primarily involves irreversible capacity loss attributed to anode instability. Side reactions on the anode surface lead to a doubling of oxygen content in graphite anodes and a 0.25-fold increase in Si/C anodes. During calendar aging, SEI growth is accompanied by complex reactions, particularly a 26-37-fold increase in Li₂CO₃. Finally, the study summarizes the side reaction processes during storage and discusses the mechanisms by which various factors influence calendar degradation. Suppressing the decomposition of intermediate products and the formation of final products during storage is conducive to developing longer-lasting batteries. This work provides theoretical guidance for battery interface and material modification engineering and serves as a reference for the study of composite material electrodes.

January 2025