Improving the electrochemical performance of ternary material LiNi0.5Co0.2Mn0.3O2 by Mg2+ doping

Abstract

A carbonate co-precipitation method is used to synthesize the precursor Ni0.5−xMgxCo0.2Mn0.3CO3, and then lithium source is added to synthesize LiNi0.5−xMgxCo0.2Mn0.3O2 cathode materials doped with different proportions of Mg2+ (x = 0, 0.02, 0.05, 0.1) after high temperature calcination. The material was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray powder diffractometer (XRD), and the electrochemical properties of the material were analyzed by batteries test and electrochemical impedance spectroscopy (EIS). The results show that an appropriate amount of Mg2+ doping can stabilize the layered structure and reduce the mixing of Li+/Ni2+, which is conducive to the rapid deintercalation of lithium ions. Compared with the bare material, the samples with Mg2+ doping amount of 0.02 have significant improvements in the first coulombic efficiency (91.9 %), cycle performance (86.2 % after 100 cycles). Especially, the rate performance of Mg2+-0.02 doping sample shows an excellent capability of 130 mA h/g at 5 C, while the bare sample only has 90 mA h/g.