Comparison of electronic property and structural stability of LiMn2O4 and LiNi0.5Mn1.5O4 as cathode materials for lithium-ion batteries

The electronic property and structural stability of LiMn2O4 and LiNi0.5Mn1.5O4 with Fd (3) over bar m space group are investigated by density functional theory (DFT) plane-wave pseudopotential method. The calculated values of Mn(Ni)-O bond lengths are found to be consistent with the reported experimental values. Due to the Ni doping, the significant shortening of Mn(Ni)-O bond strengthens the structural stability of spinel. The electronic properties of spinel show that the bonding between O and metal (Mn and Ni) is also strengthened due to the Ni doping, and then it improves the structural stability of LiNi0.5Mn1.5O4. Ni-doped spinel has a lower formation enthalpy than that of the pristine, indicating that the Ni doping improves the structural stability of spinel. (C) 2010 Elsevier B.V. All rights reserved.