Synthesis and electrochemical characterization of nano-CeO2-coated nanostructure LiMn2O4 cathode materials for rechargeable lithium batteries

LiMn2O4 spinel cathode materials were coated with 0.5, 1.0, and 1.5 wt.% CeO2 by a polymeric process, followed by calcination at 850 °C for 6 h in air. The surface-coated LiMn2O4 cathode materials were physically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron microscopy (XPS). XRD patterns of CeO2-coated LiMn2O4 revealed that the coating did not affect the crystal structure or the Fd3m space group of the cathode materials compared to uncoated LiMn2O4. The surface morphology and particle agglomeration were investigated using SEM, TEM image showed a compact coating layer on the surface of the core materials that had average thickness of about 20 nm. The XPS data illustrated that the CeO2 completely coated the surface of the LiMn2O4 core cathode materials. The galvanostatic charge and discharge of the uncoated and CeO2-coated LiMn2O4 cathode materials were measured in the potential range of 3.0–4.5 V (0.5 C rate) at 30 °C and 60 °C. Among them, the 1.0 wt.% of CeO2-coated spinel LiMn2O4 cathode satisfies the structural stability, high reversible capacity and excellent electrochemical performances of rechargeable lithium batteries.