Structural properties of Li_xMn₂C₄ as investigated by molecular dynamics and density functional theory

We performed density functional calculations and molecular dynamics (MD) simulations to study the structural properties of LiMn₂O₄. The periodic density functional calculations revealed that LiMn₂O₄ had a locally distorted structure due to the different local structures around Mn³⁺ and Mn⁴⁺. The trajectory plots of Mn³⁺ in Li_0.4Mn₂O₄ at 300 K obtained by MD simulations indicated that Mn³⁺ ions moved easily from the 16d site, which is the original position of Mn₃₊ ion in the spinel structure. It was observed that the Mn³⁺ ions moved with greater ease at low lithium concentrations, resulting in unstable Li_xMn₂O₄ structures.