Dynamics of lithium ions on a silicene anode grown by vapor deposition using Morse and MEAM potentials

Silicene, the silicon analogue of graphene, has been theoretically envisioned as a material with great potential applications, especially as an anode in lithium-ion batteries. However, the understanding of its behavior as an anode remains unclear, as research in this area is still in its preliminary phases. Furthermore, existing studies do not account for defects commonly found in silicene layers, which could potentially alter its behavior as an anode. Therefore, this study investigates the dynamics of Li ions on a defective silicene layer using molecular dynamics simulations and two distinct interatomic potentials: Morse and 2NN-MEAM. The results show that with both potentials, Li ions tend to position themselves in the middle of Si rings with six or more elements without significantly deforming the nearby lattice. However, the 2NN-MEAM potential causes severe deformation during Li diffusion on rings with five or less elements, making it impractical to investigate silicene as anode. In contrast, the Morse potential manages to maintain the silicene's structure. Nevertheless, during the insertion of Li ions into the anode’s channel, Si adatoms create barriers to Li diffusion, damaging the silicene structure. These results cast uncertainty upon the feasibility of employing silicene as anode.