Effect of high-temperature crystallization on the electrochemical properties of LiNi0.5Co0.2Mn0.3O2 synthesized from a lithiated transition metal oxide precursor

The lithiated transition metal oxide precursor (LNCMO) with typical alpha-NaFeO2 structure and imperfect crystallinity, obtained from a hydrothermal process, was pretreated at 500 A degrees C and then subjected to sintering at 800-920 A degrees C to synthesize the ternary layered LiNi0.5Co0.2Mn0.3O2 (NCM523). X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge/discharge testing were used for investigating the effect of the high-temperature crystallization on the properties of the NCM523 cathode materials. The results show that the materials heated at 880-900 A degrees C possess superior cation ordering, perfect crystallinity, and excellent electrochemical performances, among which the material heated at 900 A degrees C delivers better performances, with the initial discharge capacity of 152.6 mAh g(-1) at 0.5 C over 3.0 to 4.3 V and the capacity retention of 95.5% after 50 cycles. Furthermore, the effect of the high-temperature crystallization on the Li+ diffusion coefficient, potential polarization, and electrochemical resistance are discussed.