Preparation And Properties Of Optimization Of Lithium-rich Manganese-based Cathode Material XLi₂MnO₃·（1-x） Li (Mn_1/3Co_1/3Ni_1/3)O₂

With the increasing for energy in nowadays society, the electrochemical performance of the lithium ion battery is urgent to be improved. Lithium-rich manganese-based cathode materials receives a great deal of attention owing to their high discharge capacity, high operation voltage, and etc. In this paper, xLi2MnO2·(1-x) Li (Mn1/3Co1/3Ni1/2) O2have been synthesized by a simple co-precipitation method in metal salt-NH3-NaOH system.NaOH as precipitant, NH3·H2O as complex. The influence of synthetic conditions and proportion of raw materials on the structure, morphology and electrochemical properties of the samples have been carefully investigated by XRD, SEM, EDS and electrical performance testing. The main results for this study results are as follows:(1) As x=0.4, The optimized synthesis Conditions of lithium-rich manganese-based cathode material were pH value is10.5, ammonia concentration is0.5mol/L, reaction time is30h, calcination temperature is900℃, lithium content is15%.The crystal structure of the sample is typically layered hexagonal lattice of a-NaFeO2.It has good crystallinity, moderate particle uniform particle size distribution and excellent charge and discharge capacity, which is more than307.7mAh/g and228.1mAh/g in the voltage range of2.5-4.8V at0.1C with the coulomb efficiency of74.13%.The initial discharge capacity is more than180mAh/g at0.5C and the capacity retention rate is more than96%after30cycles.(2) The morphologies of synthesis precursors with different x values are all analogous spherical particles and the actual components are consistent with the theoretical values. When x=0.3, the precursor particle has the best spherical morphology. With the increase of x value, the content of Li2MnO3phase in lithium-rich manganese-based cathode material has gradually increased; the intensity of x-ray diffraction peaks of the lithium cathode materials became more and more sharp which means that the crystallization degree of them had get better; the initial particle size became bigger and the charge-discharge performance and cycle performance is getting better.