Preparation Of High Density Lini_1/3co_2/3-xal_xo₂ And Lini _1/3co_1/3 Mn_1/6al _1/6o₂ As Cathode Material For Lithium Ion Battery By A Molten Salt Method

The performances of lithium-ion battery are depended on that of cathode materials. With the development of lithium-ion battery industry, people on the performance of cathode materials have become increasingly demanding. Now the commercially available cathode materials of lithium ion battery LiCoO₂, etc, are certain restrictions by limitation themselves. Recently, people synthesized a series of cathode materials with better properties by doping. Lower production costs of these materials, rich in materials, environmental friendly, structural stability, and good electrochemical performance, as the driving force of the active material of lithium ion batteries have great potential.In this paper, the current research actuality of lithium-ion battery was summarized and the effects of single doping, multiple doping and synthesized methods of lithium-ion battery on the performances of cathode materials were analyzed. The paper firstly discussed the effect of materials adding method, liquor adding speed, pH value of the end solution, drying method and sulfate concentration on the tap-density of precursor Ni_1/3Co_1/3Al_1/3(OH)₂, and synthesized the Ni_1/3Co_1/3Al_1/3(OH)₂ precursor with high tap-density; Then the eutectic salt 0.38LiOH·H₂O-0.62LiNO₃ mixed with the precursor Ni_1/3Co_1/3Al_1/3(OH)₂ and reacted at high temperature to prepare LiNi_1/3Co_1/3Al_l/3O₂. We compared with the performances of materials prepared by single lithium salt and others with simple mixing ratio, and discussed the effect of synthesized time and temperature on its structure and electrochemical performances in order to find the most appropriate temperature. The results showed that the materials prepared by eutectic salt, which its crystal structure and electrochemical performances was significantly better than that of prepared by single lithium salt and others with simple mixing ratio. On this basis, we synthesized the cathode materials LiNi_1/3Co2/3-xAlxO₂ and quaternary system materials LiNi_1/3Co_1/3Mn_1/6Al_l/6O₂ with different aluminum content by eutectic salt method, and discussed the effect of aluminum content on tap-density, crystal structure and electrochemical performances of the materials.