For the silicon particles used as anode for lithium ion batteries, there is always a native oxide layer on the surface, whose role on electrochemical performance of silicon electrode need to be understood. The actual thickness of the oxide layer may also vary due to the manufacturing processes. As the size of the silicon particle becomes smaller, this oxide layer will play a more important role as it takes up a larger volume and weight percentage. Previous study suggests that the presence of oxide layer harms the initial performance of the silicon anodes in a non-aqueous system. However, the effect of the oxide layer on the long cycling performance of the electrodes has not been well studied.
Here we investigated the effect of oxide layer on the electrochemical performance of silicon anodes by growing the oxide layer of Si nanoparticles in a controlled manner. Si nanoparticles with an average size of 80 nm was used. LiPAA and carbon black was used to fabricate the electrodes. Brunauer-Emmett-Teller (BET) surface analysis, transmission electron microscopy as well as Fourier-transform infrared spectroscopy were performed to characterize the silicon nanoparticles. The stability of the silicon nanoparticles with different oxide layer thickness during electrode fabrication process was compared. Electrochemical performance of the silicon electrodes of different thicknesses was also analyzed and compared.

Acknowledgement

We gratefully acknowledge the support from the U.S. Department of Energy’s (DOE) office of Energy Efficiency & Renewable Energy (EERE) Vehicle Technologies Office. This work is performed at Argonne National Laboratory, a U.S. Department of Energy Office of Science Laboratory operated under Contract No. DE-AC02-06CH11357