Comparison of Li/Ni antisite defects in Fd-3Â m and P4332 nanostructured LiNi0.5Mn1.5O4 electrode for Li-ion batteries

Nanostructured LiNi0.5Mn1.5O4 with two different space groups (P4332 and Fd-3m) were synthesized respectively, by using ammonia-mediated carbonate precipitation. X-ray diffraction and Rietveld refinement revealed that Li/Ni antisite defects exist in ordered as well as disordered LiNi0.5Mn1.5O4 cathode materials. Although the degree of Li/Ni antisite defects in Fd-3 m space group was larger compared with that in P4332 space group, it showed better electrochemical performance. Electrochemical impedance spectroscopy confirmed that the LiNi0.5Mn1.5O4 with an Fd-3 m space group has lower charge transfer resistance. Combined with differential curves, we further revealed that there is a faster phase transition during the Li+ intercalation process in the LiNi0.5Mn1.5O4 with an Fd-3 m space group than in the LiNi0.5Mn1.5O4 with a P4332 space group.