Structural properties and mechanical stability of lithium-ion based materials. A theoretical study

An extension of the existing force field for classical simulations was derived, and applied to Li2TiO3, Li2SnO3, Li2SiO3 and other oxides such as SiO2 and SnO2. Using density functional theory, bulk properties such as elastic constant tensor components, Bulk, Shear and Young's modulus were computed. This force field was subsequently applied to calculate the bulk properties of some lithium-based materials (Li2MO3 where M = Sn4+, Si4+ and Ti4+), as well as to explore their elastic stability and isotropy. The doped Li2MO3 materials reveals the improvements-deteriorations effect of their mechanical properties as well as ductile/stiffness character. The capability of the force fields parameters is verified by testing the structural and mechanical properties of monoclinic Li2Si2O5, Li2Ti6O13 and the unreported monoclinic Li2Sn6O13. The results in general are in good agreement with previous experimental and theoretical studies. We propose that monoclinic Li2Sn6O13 can also be obtained experimentally via Sn/Ti ion exchange.