Hydrothermal synthesis of layered Li[Ni1/3Co1/3Mn1/3]O2 as positive electrode material for lithium secondary battery

In attempts to prepare layered Li[Ni1/3Co1/3Mn1/3]O2, hydrothermal method was employed. The hydrothermal precursor, [Ni1/3Co1/3Mn1/3](OH)2, was synthesized via a coprecipitation route. The sphere-shaped powder precursor was hydrothermally reacted with LiOH aqueous solution at 170 °C for 4 days in autoclave. From X-ray diffraction and scanning electron microscopic studies, it was found that the as-hydrothermally prepared powders were crystallized to layered α-NaFeO2 structure and the particles had spherical shape. The as-prepared Li[Ni1/3Co1/3Mn1/3]O2 delivered an initial discharge of about 110 mA h g−1 due to lower crystallinity. Heat treatment of the hydrothermal product at 800 °C was significantly effective to improve the structural integrity, which consequently affected the increase in the discharge capacity to 157 (4.3 V cut-off) and 182 mA h g−1 (4.6 V cut-off) at 25 °C with good reversibility.