Tight-binding quantum chemical molecular dynamics study of cathode materials for lithium secondary battery

Our tight-binding quantum chemical molecular dynamics (TBMD) program was applied to the investigation of the structural and electronic properties of LixMn2O4. The calculated lattice constants of the LiMn2O4 and λ-MnO2 were 8.17 and 8.08 Å, respectively, which are in good agreement with experimental results. The electronic analysis showed that the manganese atoms in the LiMn2O4 were separated into two groups based on their electronic states, which correspond to Mn3+ and Mn4+. We calculated the average potential for the reaction of Li+Mn2O4→LiMn2O4 and obtained the average potential of 4.2 V. The experimental value of the potential is approximately 4.0 V, indicating that our program is a powerful tool to predict the potential of various materials, as well as their atomistic and electronic structures.