Solid State Ionics, Vol.307, 26-34, 2017
Ab initio study of the electronic structure, magnetic and dynamics properties in LiMO2 and NaMO2 and (M=V and Cr) as electrode cathode material for batteries
The monoclinic structure of LiMO2 and NaMO2 are promising cathode material for batteries due to their high capacity and good stability in energy storage devices, such as batteries. By employing first principles calculations studies, we present our findings on the superior performance of LiMO2 and NaMO2 as cathode materials for battery application. Electronic properties near the Fermi energy originate almost exclusively from 3d-t(2g) states. There is a small 3r-type of p-d orbital hybridization overlap between the metal and oxygen which causes a narrow peak at E-F. By analyzing spin-polarized calculations, it reveals an electronic spin polarization ground state order at higher energy. Since direct d-d and d-p indirect hybrid orbital exchange interaction also play major role. From the electron localization function (ELF) map, it shows clearly the ionic bonding between the transition metal oxides and lithium or sodium ions, it can be attributed exclusively to a strong inter-layer interaction. Both structural evolution and ion diffusion properties have been studied in detail as supplied by molecular dynamics (MD), to probe microscopic information of ions undergoing Brownian motion at different temperatures. This study can provide insight for understanding the de-intercalation behaviors of ion diffusion.
Keywords:Lithium-metal oxide;Electronic properties;Magnetic polaron;Dynamics simulation;Lithium ion diffusion