Structural and electrochemical characterization of LiMn2-2xLixNixO4 (0 <= x <= 0.1) cathode materials

Lithium and nickel co-doped LiMn2-2xLixNixO4 cathode materials (x= 0, 0.03, 0.05, 0.075, 0.1) were synthesized by a high temperature solid-state reaction route. The microstructures and morphologies of the samples were characterized by X-ray powder diffraction, X-ray absorption fine structure analysis and field emitted scanning electronic microscopy. The bond lengths of the MnO6 octahedrons and the electrochemical performances in both room temperature and elevated temperature (55 degrees C) were characterized and discussed in comparison with LiMn2O4 spinel. The result reveals that LiMn2-2xLixNixO4 samples have a good reversibility. It is suggested that the co-doping of lithium and nickel in LiMn2O4-based compounds could stabilize the spinel structure and improve the capacity retention of the cathode materials.