A New Mechanism of Stabilizing SEI of Si Anode Driven by Crosstalk Behavior and its Potential for Developing High Performance Si-Based Batteries

Stabilizing solid electrolyte interphase (SEI) is a key factor for determining cell performance of Silicon (Si) anode, such as safety, cycle lifetime, and calendar lifetime. Here, we found a new potential for stabilizing SEI of the Si anode, driven by crosstalk with cathode material. We investigated the effect of crosstalk on the chemistry of SEI of the Si anode as a function of three different, representative cathode materials: LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532), LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811), and LiFePO₄ (LFP). Specifically, we observed that crosstalk significantly affected the formation and growth mechanism of SEI layer on the Si anodes. Unexpectedly, dissolved Fe ions from the LFP cathode has a positive impact on the chemistry and electrochemical stability of the SEI layer of Si anode compared to the other cathodes, resulting in better electrochemical performance in terms of initial coulombic efficiency and capacity fade.