Lithium insertion mechanism inSnS2

We study lithium insertion in ${\mathrm{SnS}}_2$ by means of ${}^{119}\mathrm{Sn}$ Mössbauer spectroscopy, x-ray absorption spectroscopy at Sn $L_{I,III},$ and S K edges, and theoretical electronic structures (calculated in the density-functional theory framework). An insertion mechanism is derived according to the Li amount. It shows the influence of the ${\mathrm{SnS}}_2$-layered structure on the Sn reduction, particularly the possibility of an intermediate oxidation state between ${\mathrm{Sn}}^{\mathrm{IV}}$ and ${\mathrm{Sn}}^{\mathrm{II}},$ which is not observed during Li insertion in three-dimensional sulfides.