Investigation of the irreversible reaction mechanism and the reactive trigger on SiO anode material for lithium-ion battery

Abstract

To clarify the reaction mechanism of SiO anode, the chemical and the electrochemical reactions of SiO and SiO₂ with Li-metal and first principles calculations were investigated. In the chemical reactions, SiO and amorphous SiO₂ formed lithium silicide (Li₄₄Si₅) and lithium silicate (Li₂SiO₃, Li₄SiO₄) by reacting with Li. In the electrochemical reactions, crystalline SiO₂ did not react with Li though amorphous SiO₂ did do so. These results indicated that both Si area and amorphous SiO₂ area in SiO matrix play an important part in SiO charge–discharge process. This suggests that the dangling-bond in amorphous SiO₂ can react with Li easily. This finding was also confirmed by first principles calculations using VASP code.