Abstract: Theoretical studies on the structures, stabilities and electronic properties of Si_nLi (n=1-10) clusters were carried out by the density functional theory (DFT). The results show that lithium atom prefers to stay at the surface of cluster and likes to be adsorbed on the bridge site. The binding energies indicate that the stabilities of Si_nLi clusters can be enhanced by adsorption of lithium atom. Additionally, lithium atom binding energies show that the interaction between lithium atom and silicon cluster increases as decreasing the cluster size, which is an important factor for the amorphization process upon lithiation of the silicon based anode materials for Li-ion batteries. The ionization potential, electron affinity potential, chemical potential and energy gap of the Si_nLi clusters all indicate that Si₄Li and Si₇Li are easier to lose α electron to form cationic clusters.

Key words: silicon based anode material, lithium-silicon cluster, ground state structure, electronic property