Multifunctional Surface Coating As Artificial Solid Electrolyte Interphase for Lithium Ion Batteries

Surface modification on electrode has been reported to be an effective way to mitigate the mechanical degradation, improve the cycling stability, coulombic efficiency, and abuse tolerance. However, less work has been done to fundamentally understand its role on the formation of solid electrolyte interphase (SEI) and lithium transport. In this talk, we reported some important findings on the effect of surface coating on SEI formation. We found that the oxide coating can suppress electrolyte decomposition, therefore significantly reduced the SEI thickness (from around 20 nm thick without coating down to 1nm). Al₂O₃ coating also went through the structural changes which better facilitate charge transfer. We have demonstrated that the self-modified coating served as an artificial SEI layer which not only stabilized the interface between electrolyte and electrode, but also mitigated the mechanical degradation of electrode and improved the cycling stability. We will give a few examples to show how surface coating can help improve the battery performance from different aspects.