The Synthetic Optimization And Properties Research Of Li_xMn_yNi_zCo_1-x-y-zO₂Battery Anode Materials

LiCoO2was the first commercialized lithium ion batteries due to its advantages，suchas high voltage, stable discharge, high specific energy and excellent recycling ability. Butit also has some disadvantages, for example, Co was scare resource, expensive and heavilycontaminate the environment, and these have become important factors to restrict itsapplication.Ni-Co-Mn ternary system LiNi1/3Co1/3Mn1/3O2was considered as the cathodematerials which are the greatest potential to replace LiCoO2.LiNi1/3Co1/3Mn1/3O2wasexpected widely used in the field of electric vehicles (EV) and hybrid electric vehicles(HEV).In this paper, LiNi1/3Co1/3Mn1/3O2cathode material was prepared by co-precipitationmethod, and the preparation conditions were optimized, and it had a research on differentmetal oxides coated and different coating of alumina, and the phase structure and surfaceappearance of the cathode materials were characterized by XRD and SEM, and theelectrical properties of the samples were studied by high performance battery testingsystem, AC impedance, and cyclic voltammetry.Respectively used sulfates and acetates to prepared LiNi1/3Co1/3Mn1/3O2cathodematerials, and compared products of the two different system, then draw conclusions: theparticles of the cathode material prepared by acetates was small, and the electrochemicalproperties was good. Prepared the LiNi1/3Co1/3Mn1/3O2cathode material, and studiedcalcination temperature and calcination time which was825℃and10h. The preparedLiNi1/3Co1/3Mn1/3O2cathode material possesses laminate structure, regular shape, theinitial discharge specific capacity was156.76mAhg-1, after20charging and discharging,the specific capacity was145.18mAhg-1, the retention of the capacity was92.61%, the EISshowed that under these conditions, the intercalation and deintercalation of the lithium ionmeet less resistance, and moving charges more easily.Prepared cathode materials LiNi1/3Co1/3-xMn1/3MxO2(M was metal, x=0.1) that coated different metal oxides. The materials had no impurity after coated MgO and Al2O3, but thediffraction was offset after coated ZnO, and this results showed that the structure of thematerial was changed, and the crystal structure of materials not changed after coated MgOand Al2O3. After coated Al2O3, MgO and ZnO, the initial discharge specific capacity were148.9mAhg-1,144.44mAhg-1and141.14mAhg-1respectively. The capacity retention ratiowere95.27%,94.54%and93.98%, after20cycling, these showed that the cyclingperformance of the material was improved. We studied the electrochemical properties ofthe material LiNi1/3Co1/3-xMn1/3AlO2(x=0.1,0.05,0.025) by coated different amount ofAl2O3.When x equals0.5, the material own the best cycling performance, and the initialdischarge specific capacity of the material was156.29mAhg-1, after20times cycling, thedischarge specific capacity was150.64mAhg-1, and the capacity retention ratio was96.38%, which has increased3.77%than no coated with the optimum condition.