Preparation And Properties Of Lithium-ion Battery Cathode Materials XLi₂MnO₃·?1-x?LiNi_1/3Co_1/3Mn_1/3O₂

With coal,oil,natural gas and a series of non-renewable energy over-consumption,people began to look for new energy storage material in order to meet the needs of economic development.Layered lithium-rich manganese cathode material xLi₂MnO₃·?1-x?LiMO2 because of its high charge-discharge capacity and low cost has been widely concerned.Such cathode material has a new reaction mechanism and the special microstructure.At the same time,there are some problems including first low coulomb efficiency and cycle voltage decay,which requires us to overcome through continuous research.In this work,xLi₂MnO₃·?1-x?LiNi1/3Co1/3Mn1/3O2 were prepared using high-temperature solid-phase method,solid phase high temperature ball milling,sol-gel method and sol-gel high temperature ball milling method.The effects of different heat treatment time,heat treatment temperature and different x values on material morphology,structure and electrochemical properties were tested and analyzed.xLi₂MnO₃·?1-x?LiNi1/3CO1/3Mn1/3O2 prepared at 800? for 10 hours with x value of 0.5 presents the best performance.The first discharge capacity is 89.5 mAh·g-1 and capacity loss is 29.1%at 0.1C rate.After 30 cycles,capacity retention rate is 97.6%at 0.1 C rate.Li₁MnO₃·?1-x?LiNi1/3Co1/3Mn1/3Mn1/3O2 prepared at 600? with x value of 0.5 after high temperature ball milling 2 hours presents the best performance.The first discharge capacity is 111.7mAh·g-1 and capacity loss is 30.3%at 0.1C rate.After 30 cycles,capacity retention rate is 85.5%at 0.1 C rate.Using sol-gel method,xLi₂MnO₃·?1-x?LiNi1/3Co1/3Mn1/3O2 synthetised at 950?for 10 hours also presents the best performance.The first discharge capacity is 319.7 mAh·g-1 and capacity loss is 27.4%at 0.1C rate.After 30 cycles,capacity retention rate is 73.7%at 0.1 C rate.xLi₂MnO₃·?1-x?LiNi1/3Co1/3Mni/3O2 prepa.red at 600? with x value of 0.5 after high temperature ball milling 2 hours presents the best performance.The first discharge capacity is 178.4mAh·g-1 and capacity loss is 31.3%at 0.1C rate.After 30 cycles,capacity retention rate is 75.3%at 0.1 C rate.