Stabilities and structures of β- and α-Sn nanoparticles are studied using
density functional theory. Results show that β-Sn nanoparticles are more
stable. For both phases of Sn, nanoparticles smaller than 1 nm (∼48 atoms) are
amorphous and have a band gap between 0.4 and 0.7 eV. The formation of band
gap is found to be due to amorphization. By increasing the size of Sn
nanoparticles (1–2.4 nm), the degree of crystallization increases and the band
gap decreases. In these cases, structures of the core of nanoparticles are
bulk-like, but structures of surfaces on the faces undergo reconstruction.
This study suggests a strong size dependence of electronic and atomic
structures for Sn nanoparticle anodes in Li-ion batteries
