Ab-Initio and Experimental Studies of Silicon Dioxide Anode Material for Lithium Ion Battery

Silicon sub oxide SiOx (x ≤ 2) has been considered as a potential LIB anode. Although SiOx is thermodynamically unstable at all temperature, it consists of amorphous Si and SiO2 clusters leading to active/ inactive structures that help buffer the strain during cycling and hence much improved reversible capacities. It was thought that the role of SiO2 was buffer matrix of Si, however, some researchers reported that amorphous SiO2 reacts with Li and can be used for anode material for LIBs. And recently, communities both academy and industry have considered the idea of tailoring oxidation of proportionated SiOx to increase the initial capacity and cycle ability compared to Si. Despite these encouraging developments of Si oxide anode, the fundamental understanding is still limited and no atomistic study has been reported.

In this presentation, we study the structural stability of SiOx (0 ≤ x ≤ 2) , reaction mechanisms of Li in c-SiO2, and possibility reaction in amorphous Si sub oxide using both theoretical and experimental method. Based on the analysis of SiO₂, we also discuss structural evolution and voltage profile of LiySiOx (0 ≤ y ≤ 4) during lithiation with respect to oxygen contents (0 ≤ x≤ 2).