Preparation And Electrochemical Properties Of Layered Cathode Materials For Lithium-ion Batteries

Lithium-ion battery cathode materials such as Li[Mn_1/3Ni_1/3Co_1/3]O₂ and lithium-rich materials have been extensively studied for their excellent electrochemical performance.However,these two materials also have some shortcomings,they are not safe and lower cycle performance compared to LiMn₂O₄?spinel??LiFePO4?LFP?.In particular,the capacity of lithium-rich is easy to decay in the process of its cycle,which delayed their commercialization.In this paper,we mainly explore the preparation technology of Li[Mn_1/3Ni_1/3Co_1/3]O₂ and Li[Li_0.2Mn_0.56Ni_0.16Co_0.08]O₂,and the effect of different synthesis conditions on the crystal structure of cathode material as well as the discharge performance,the main conclusions are as follows:1.the high crystallinity and ordered layer structure Li[Ni_1/3Mn_1/3Co_1/3]O₂ cathode materials were successfully prepared by the oxalate co-precipitation and different calcinations temperature;as expected,the sample S-850 shows the higher discharge capacity of 176 mAh/g,excellent rate capability and good cycle stability,and after 30 cycles its discharge capacity still remain 166 mAh/g,which are 94%of its initial discharge capacities;the XRD and SEM were used to evaluate the structural integrity and morphology of the samples.The results show the structural integrity and degree of cation mixing strongly depend on the calcinations temperature.2.Li[Mn_1/3Ni_1/3Co_1/3]O₂ were successfully prepared by sucrose-assisted method.The structure and electrochemical properties of the prepared materials under different temperatures were investigated.The results show that Li[Mn_1/3Ni_1/3Co_1/3]O₂ prepared at 900? has the best electrochemical property,its first discharge capacity is 172 mAh/g,then we use solid state reaction method to synthesis Li[Mn_1/3Ni_1/3Co_1/3]02,and And compare the advantages of the two methods,we can see sucrose-assisted method is better than solid state reaction method in electrochemical properties.3.Lithium-rich Li[Li_0.2Mn_0.56Ni_0.16Co_0.08]O₂ material was prepared by sucrose-assisted method.The structure and the charge-discharge mechanism of lithium-rich materials calcined at different temperatures was studied.It was found that the lithium-rich material obtained by calcinating at 900? had the best electrochemical performance.