Density functional theory study of lithium intercalation for 5 V LiNi0.5Mn1.5O4 cathode materials

LiMn2O4 and LiNi0.5Mn1.5O4 spinel cathode materials powder was successfully synthesized by an ultrasonic-assisted co-precipitation (UACP) method. The geometry structures of LiMn2O4 and LiNi0.5Mn1.5O4 are successful optimized and the corresponding electronic structures are then calculated by density functional theory (DFT) plane-wave pseudopotential method. The initial discharge capacity of LiMn2O4 and LiNi0.5Mn1.5O4 are 130.9 and 130.5 mAh·g− 1, respectively. The calculated average voltages of LixMn2O4 and LixNi0.5Mn1.5O4 at the range of 0 ≤ x ≤ 1 are 4.28 and 4.66 V, and the errors are 4.39% and 0.74% compared with electrochemical experiment value, respectively. The increase of voltage after doping is related with the different filling of electrons in M–O6 octahedron framework after the intercalation/deintercalation of Li+, and lithium element exists in spinel materials in form of ions.