Abstract:The layered Li[Ni_1/3Mn_1/3Co_1/3]O₂ was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni_1/3Co_1/3Mn_1/3]₃O₄ and lithium hydroxide as raw materials. The physical and electrochemical behaviors of Li[Ni_1/3Mn_1/3Co_1/3]O₂ were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and electrochemical charge/discharge cycling tests. The results show that the difference in pretreatment process results in the difference in compound Li[Ni_1/3Co_1/3Mn_1/3]O₂ structure, morphology and the electrochemical characteristics. The Li[Ni_1/3Mn_1/3Co_1/3]O₂ prepared by solution phase route maintains the uniform spherical morphology of the [Ni_1/3Co_1/3Mn_1/3]₃O₄, and it exhibits a higher capacity retention and better rate capability than that prepared by ball mill method. The initial discharge capacity of this sample reaches 178 mA∙h/g and the capacity retention after 50 cycles is 98.7% at a current density of 20 mA/g. Moreover, it delivers high discharge capacity of 135 mA∙h/g at a current density of 1 000 mA/g.

Key words: lithium ion batteries; Li[Ni_1/3Co_1/3Mn_1/3]O₂; carbonate co-precipitation method; pretreatment process; electrochemical characteristics