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 deg 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 alpha-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 hg-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 25DGC with good reversibility.