Influence of pretreatment process on structure, morphology and electrochemical properties of Li[Ni1/3Co1/3Mn1/3]O2 cathode material
(Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education,
School of Chemistry, Xiangtan University, Xiangtan 411105, China)
School of Chemistry, Xiangtan University, Xiangtan 411105, China)
Abstract: The layered Li[Ni1/3Mn1/3Co1/3]O2 was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni1/3Co1/3Mn1/3]3O4 and lithium hydroxide as raw materials. The physical and electrochemical behaviors of Li[Ni1/3Mn1/3Co1/3]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[Ni1/3Co1/3Mn1/3]O2 structure, morphology and the electrochemical characteristics. The Li[Ni1/3Mn1/3Co1/3]O2 prepared by solution phase route maintains the uniform spherical morphology of the [Ni1/3Co1/3Mn1/3]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[Ni1/3Co1/3Mn1/3]O2; carbonate co-precipitation method; pretreatment process; electrochemical characteristics