Reaction Mechanism of Metal Silicide Mg2Si for Li Insertion

Electrochemical reaction of the SiMn/C composite for anode in lithium ion batteries

“…Silicon can alloy with lithium to form four different phases Li 12 Si 7 , Li 7 Si 3 , Li 13 Si 4 and Li 21 Si 5 , and the total theoretical capacity for the reaction of lithium and silicon to Li 21 Si 5 is 1967 mAh g −1 which corresponds to 4.2 mol lithium per mol silicon [12]. Silicon oxide [13,14], Si-based alloys such as SiAg [15,16], SiMg [17][18][19], SiCa [20], SiNi [21], SiFe [22] and Si/C composites [23][24][25] have been reported as anodes for lithium ion batteries. Though the cycle stability of Si-based materials was improved to some extent, the initial irreversible capacity loss was so large that they cannot be applied for commercial use.…”

Investigation of CrSi2 and MoSi2 as anode materials for lithium-ion batteries

“…The in situ formation of the inactive metal compound acts as a matrix that mitigates the volume change. Mg 2 Si has an anti-fluorine structure that was shown to accommodate Li-insertion according to the following path: Mg 2 Si + 2Li + 2e → Li 2 MgSi + Mg, followed by reaction of Mg with lithium to form an MgLi alloy [14,16]. However, other groups reported the following reaction pathway [7,8]: Mg 2 Si + 3Li + 3e → 2MgLi + SiLi.…”

Synthesis temperature dependence of the structural and electrochemical properties of Mg2Si anodic materials prepared via a hydrogen-driven chemical reaction

“…As shown, the lithium insertion occurred below 0.2 V, at approximately 0.17 V. Interestingly, there are three lithium extraction peaks at 0.19, 0.26 and 0.60 V in the DCPs, which indicates that the removal of Li ions is a multiple reaction process. As previously reported [7][8][9][10][11], there are two reaction mechanisms for Li insertion into and extraction from Mg 2 Si. Kim et al [7] demonstrated that lithium is first inserted into the octahedral interstices of Mg 2 Si, and then the Mg 2 Si structure is destroyed to form binary Li-Si and Li-Mg alloys, which is a one-step reaction process.…”

“…In recent years, magnesium silicide (Mg 2 Si), a promising anodic material, has attracted significant attention due to its favorable voltage profile, high specific capacity, natural abundance, low cost, and environmental compatibility [7][8][9][10][11]. Unfortunately, it is difficult to prepare pure Mg 2 Si using conventional melting techniques due to the large discrepancy in the melting points of Mg and Si (differing by∼ 760°C), the lack of solubility, and the low boiling temperature (1090°C) and high reactivity of Mg [12][13][14][15][16].…”