Molecular dynamics simulation of hollow and porous amorphous silicon nanowires coated with amorphous aluminum oxide

Silicon causes structural changes and residual stresses during the process of lithium-ion penetration. Aluminum oxide coatings with an optimal thickness can prevent the structural variations and failure of the anode, though it will affect the ionic conductivity. In this research, the mechanical and electrochemical properties of the aluminum oxide-coated silicon nanowires are investigated by the molecular dynamics simulations. The results of the simulations show that the capacity increases, and the dimensional stability is maintained to a suitable extent by applying the void space or creating porosity in the coated nanowires. Furthermore, the volumetric changes for the base sample decrease from 56.3% to 10.25% and 19.1% for porous and hollow Si nanowires samples, respectively. Nevertheless, the capacity is increased from 1015.3 to 1063.8, 1219.6, and 1573.3 mAhg⁻¹ for porous, closed, and open-hole samples, respectively. The radial distribution of the residual stresses and elemental mapping are also measured to investigate the effect of porosity and void space on the amorphous nanowires.