Stable Ionic Conductive Layer on Si Nanoparticles inside Si/C Composite for High-Performance Lithium-Ion Battery Anode

In this study, we developed a simple and effectual method to form the stable Li ionic conductive layers for Si-based LIB anode materials. (1) For the purpose of maintaining a Li ionic conductive solid electrolyte interphase (SEI) during operation, the protective oxide coating for Si/C composite is practical, which can be simply applied by mixing a poly(vinyl alcohol)-PO₄ with the Si/C composite. The in-depth analysis revealed that the oxide coating reduces the loss of high ionic conductive SEI (Li₂O), resulting in the formation of a stable SEI [1-2]. (2) In the manufacturing step, stable Li ionic conductive layer (Li₂SiO₃) can be successfully fabricated on the Si nanoparticles inside Si/C composite by simply mixing the Li₂O nanoparticles with coal tar pitch. From the electrochemical measurements applied to various cells, it was demonstrated that the Si/C composite with stable Li₂SiO₃ layers show a considerably high performance in stability [3]. The design of this study and analysis provides the direction to enhance the stability of Si-based anode materials at low cost for developing high performance LIB.

[1] Y. S. Kim et al, Appl. Mater. Interfaces 8, 30980 (2016)
[2] S. H. Kim et al, J. Power Sources 407, 1 (2018)
[3] Y. S. Kim et al, Submitted for Publiction