Simple solid-state method for synthesis of Li[Li0.20Mn0.534Ni0.133Co0.133]O2 cathode material with improved electrochemical performance in lithium-ion batteries

Abstract

Layered Li[Li0.20Mn0.534Ni0.133Co0.133]O2 cathode materials for Li-ion battery were successfully prepared by a novel simple solid-state method using acetate or carbonate as a precursor under high temperature, and were then surface-modified with nanostructured alumina (Al2O3). The prepared cathode materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM), transmission electron microscope (TEM), and electrochemical measurements. The XRD results show that all the cathode materials possess an α-NaFeO2 structure type with high crystallinity. SEM and TEM images reveal that the cathode materials have a monodisperse nonspherical morphology and the surface became rough but their morphology did not change very much after Al2O3 coating. XRF test proved the presence of Al2O3 in the samples after coating treatment. The electrochemical measurements exhibit that the Al2O3-coated cathode materials have a higher capability and cycling performance in lithium-ion battery than that of uncoated samples. Further, electrochemical impedance spectra (EIS) measurement shows that the Al2O3 nanoparticles on the surface of the cathode materials reduced side reactions during cycling electrode/electrolyte interface and provided a balanced electronic and Li-ion conductivity. This promising technology for making high performance electrodes would inspire the design and development of a wide range of other battery-related materials in a more eco-friendly way.