Co O _{Lithium-ion Battery Cathode Material LiNi 0.8 0.15 Al 0.05 2 Preparation And Properties}

With the development of lithium-ion battery research, high nickel cathode materials LiNi1-x-yCoxAlyO2has get a lot of attention, LiNi1-x-yCoxAlyO2material is considered to be a very promising cathode material of next-generation lithium-ion battery. In these materials, LiNi0.8Co0.15Al0.05O2(NCA) is the most mature, which has superior capacity and rate performance, can be used as battery cathode material. This paper reviewed the research development of the NCA cathode materials, studied the preparation conditions of NCA cathode material using sol-gel process, and used cyclic voltammetry to research the effect of preparation conditions on the lithium ion diffusion coefficient of NCA cathode material.In this paper, we synthesized the precursor of NCA cathode materials using sol-gel method, and obtained the desired cathode materials after heat treatment. Through TG/DSC tests, we determined the pretreatment temperature of the precursor (550℃) and the crystal formation temperature for NCA cathode materials (after700℃, but not exceed900℃). Using the TG/DSC, SEM, XRD, electrochemical performance testing, we examined the effect of the preparation conditions on the morphology, structure and electrochemical properties, including the complex quantity, sintering temperature, sintering time, the lithium ratio, complex materials and solvents. After these researches, we obtained the optimum synthesis conditions:the complex is maleic acid, the ratio of complex to transition metal is1, the ratio of lithium to transition metal is1.00, the solvent is deionized water; the resulting solution was stirred in magnetically stirred oil bath for24h at ambient temperature, then at80℃4h. the last stirred at120℃until the gel was completely dry; resulting precursor was pretreated at550℃for12h, and then follow this way of heat treatment to stir:550℃12h,800℃24h. In this paper, we assembled the NCA cathode material obtained under different conditions into button batteries. They were taked to cyclic voltammetry test. Using the second test data, we obtained the revisibity of the delithiation reaction and lithium ion diffusion coefficient. Through the results, we studied the effect of different conditions on the revesibility of redox reaction and lithium ion diffusion coefficient. The results were consistent with optimal synthesis conditions obtained through the morphology, structure and electrochemical properties studying. It provides a new way to study the preparation of cathode materials.