Hydrothermal Synthesis Of LiNi_0.9Co_0.1O₂ And LiNi_1/3Co_1/3Mn_1/3O₂ For Lithium Ion Batteries

Lithium ion battery is one of the newest energy sources which has developed recently, and it has an extensive application prospect. For the development of the lithium ion batteries, cathode materials play an important role. Therefore, the investigation of high performance cathode materials has become the central issue in nowadays.In this paper, composite cathode materials LiNi_0.9Co_0.1O₂ and LiNi_1/3Co_1/3Mn_1/3O₂ were prepared by hydrothermal method. The process conditions (matching of reactants, reacting temperature, reacting time) which effected the target product were also discussed. The products were characterized by XRD, TEM and EDS. The major researches are as follows:1. The synthesis of LiNi_0.9Co_0.1O₂ by hydrothermal method. Layer structured nano-powders LiNi_0.9Co_0.1O₂ were successfully obtained by hydrothermal method, the particle size was about 10nm. The results are listed as follows:1) Along with the rise of Li/(Ni+Co), the crystal's layer structure becomes more and more obvious. When Li/(Ni+Co)=50, the product has perfect layer structure and good dispersivity.2) The lowest synthesis temperature of LiNi_0.9Co_0.1O₂ is about 150 oC, while the optimal synthesis temperature is about 220 oC. The layer structure perfecting along with the rise of synthesis temperature.3) The optimal reacting time is 10h. When shorter than 10h, the layer structure of crystal perfecting along with the extension of time; when 10h ,the layer structure is perfect, when longer than 10h, the layer structure is destroyed.2. The synthesis of LiNi_1/3Co_1/3Mn_1/3O₂ by hydrothermal method. Nano-powders LiNi_1/3Co_1/3Mn_1/3O₂ were successfully prepared by hydrothermal method, the particle size is about 10nm. The results are listed as follows: 1) The optimal Li/(Ni+Co+Mn) is 30. The crystal's crystallinity becomes strengthen along with the rise of Li/(Ni+Co+Mn). When Li/(Ni+Co+Mn) is 50, the product contains a little of MnOOH.2) The lowest synthesis temperature of LiNi_1/3Co_1/3Mn_1/3O₂ is about 190 oC. During the range of synthesis temperature, the layer structure of LiNi_1/3Co_1/3Mn_1/3O₂ perfecting along with the rise of synthesis temperature.3) The extension of reacting time contributes to the strengthen of cystallinity and the perfect of layer structure. When the reacting time is 10h, the product has optimal cystallinity and layer structure. When longer than 10h, the cystallinity becomes weaker along with the extension of reacting time and the layer structure is destroyed. The optimal reacting time is 10h.