Theoretical studies of lithium incorporation into α-Sn(100)

Using density functional theory, we study the incorporation of Li into Sn(100). The calculations indicate that Li is more stable at interstitial sites between the topmost surface-layers of Sn(100) than at onsurface sites and bulk sites. The barrier of Li diffusion from the surface into the subsurface is very low (0.07 eV). The highest-energy barriers are for the penetration of Li from the outermost subsurface sites into deeper subsurface sites (0.22-0.25 eV). The energy barriers for the Li incorporation into the Sn(100) surface are much lower than into the surfaces of other group IV elements such as Si. Since Sn is a promising candidate to replace the currently-used graphite anodes in Li-ion batteries, the present work can help us to better understand the process of Li insertion and extraction in Sn-based anode materials for future Li-ion batteries.