Electronic Structure of LiMn_1-xM_xO₂(M=Mn, Co, Ni, Zn) as a Cathode Active Material for Li Secondary Battery by MEM/Rietveld Analysis and First Principles Calculations

Abstract

We synthesized the LiMn_1-xM_xO₂ (M=Mn, Co, Ni) and investigated the electron density map by X-ray diffraction using the Maximum Entropy Method(MEM)/Rietveld Analysis and first principles calculation. The electron density map shows that the covalent bonding of (Mn, M)-O of o-LiMn_1-xM_xO₂ is stronger than that of o-LiMnO₂. Next, we calculated the electron density of o-LiMn_1-xM_xO₂ (M=Mn, Co, Ni, Zn) using the first principles calculation by FLAPW method. The covalent bonding of Mn-O and M-O of each o-LiMn_1-xM_xO₂ is stronger than that of o-LiMnO₂ by substitution of Mn with M.