Preparation And Mg-doping Modification Of LiNi_1/3Co_1/3Mn_1/3O₂Cathode Material

The LiNi1/3Co1/3Mn1/3O2cathode materials generate the public’s interest because of their high specific capacity, low cost and excellent security. In this paper, the layered LiNi1/3Co1/3Mn1/3O2material was synthesized by high temperature calcination based on the precursor Ni1/3Co1/3Mn1/3(OH)2prepared by hydroxide coprecipitation method. And the technological parameters of the synthetic process were investigated and optimized. To improve the cycle performance of LiNi1/3Co1/3Mn1/3O2cathode materials, the Mg-doping modification was used in the coprecipitation process. The cathode materials were characterized by Particle Size Distribution, Tap-density, SEM, EDS, ICP, XRD and electrochemical properties.The effects of synthesizing technological parameters on the performance of LiNi1/3Co1/3Mn1/3O2material were investigated. And the optimum conditions were obtained as the pH value was11.0, the ammonia concentration was1.0mol·L-1, calcination temperature was950℃, calcination time was10h and the molar ratio of Li/(Ni+Co+Mn) was1.05. The results showed that the morphology outline of LiNi1/3Co1/3Mn1/3O2material was evident; the material presented layered α-NaFeO2structure and the cationic mixing was low; the initial discharge specific capacity was145.3mAh·g-1,and the discharge specific capacity was119.5mAh·g-1after50cycles.The effects of Mg-doping modification on the performance of LiNi1/3Co1/3Mn1/3O2material were carried out. The results showed that the undoped cathode materials were still standard α-NaFeO2layered structures and no obvious change in particle size. The specific discharge capacity decreased from138.2to131.1mAh·g-1for the cathode materials doped with0.03Mg after50cycles. The results indicated that though the initial specific discharge capacity decreased slightly, the cycle performance increased notably after doping Mg.