Preparation and electrochemical properties of layered LiNi0.5Co0.45Fe0.05O2 compounds for lithium ion batteries

LiNi0.5Co0.45Fe0.05O2 (LNCFO), a new layered compound, was synthesized by the solid-state method for application as a cathode material in lithium-ion batteries. The microstructure and morphology of the sample were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the material were assessed by charge–discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy. Our data confirmed that LNCFO exhibits a hexagonal α-NaFeO2 structure with the R3̄m space group and consists of layered grains. According to the charge–discharge tests, the sample prepared at 700 °C showed the best initial discharge capacity of 160.4 mA h g−1 at 0.2 C and excellent cycling ability. In addition, the samples synthesized at 700 °C also showed lower electrochemical impedance than samples synthesized at other temperatures. Our study indicates that the solid-state method is effective for synthesizing LNCFO cathode materials for lithium-ion batteries with outstanding performance.