Evaluation of Sn Nanowire Encapsulated Carbon Nanotube for a Li-Ion Battery Anode by DFT Calculations

Hybrid nanomaterial of Sn nanowire encapsulated carbon nanotube (SnNW@CNT) for a 1-D nanostructure Li-ion battery anode is evaluated by using DFT electronic structure and molecular dynamics calculations. We reveal that ultrathin SnNW is thermodynamically stable within CNT and it is prone to have a disorder structure. In addition, SnNW@CNT can enhance Li uptake as compared with pure CNT due to the energetically favorable Li-SnNW alloying process. More importantly, we reveal that an optimized SnNW@CNT has a void space thickness of similar to 5 angstrom between the nanostructures, indicating that the radial void spaces are only enough for accommodating the fully lithiated SnNW within CNT(n,0) when n < 27. The results suggest that such nanowire encapsulated nanotube materials have to be made ultrathin in order to become an effective hybrid nanomaterial for a Li-ion battery anode.