Preparation And Properties Of High Nickel Ternary Lithium Ion Battery Cathode Materials

The lithium-ion battery is considered the most competitive energy candidate for EV and HEV because of its advantages of light weight and high density.NCM811 has become one of the most promising cathode materials for high energy density batteries due to the large capacity,high operating voltage and low cost.NCM811 has higher reversible discharge specific capacity,in addition it has much lower Co content than commercial Li Co O₂,which is more economical and environmental protection.However,the cation mixing phenomenon hinders NCM811 anode materials mass production and application.In this paper,the preparation method of Li Ni_0.8Co_0.1Mn_0.1O₂ was acetate decomposition.The prepared Li Ni_0.8Co_0.1Mn_0.1O₂ was detected by XRD,SEM and a series of electrochemical detection techniques.LiNi_0.8Co_0.1Mn_0.1O₂ was prepared by decomposition of Ni（CH₃COO）₂·4H₂O,Co（CH₃COO）₂·4H₂O,Mn（CH₃COO）₂·4H₂O and Li OH·H₂O.The effects of calcination temperature and calcination time on the properties of Li Ni_0.8Co_0.1Mn_0.1O₂ were studied.The results showed that the initial discharge specific capacity of Li Ni_0.8Co_0.1Mn_0.1O₂calcined at 850°C for 15 h could reach 182.5 m Ah·g^-1.After 50 cycles,the discharge specific capacity was 114.9 m Ah·g^-1.Based on the optimal calcination conditions,the effects of different hydrogen peroxide addition and increased air flow rate during calcination on the performance of Li Ni_0.8Co_0.1Mn_0.1O₂ were studied.The results showed that when the amount of hydrogen peroxide added was the amount required for the reaction with Ni²⁺,the material obtained had good electrochemical performance,the initial discharge capacity reached 192.0m Ah·g^-1,and after 50 cycles the discharge specific capacity reached 125.9 m Ah·g^-1.LiZn_x(Ni_0.8Co_0.1Mn_0.1)_1-xO₂（x=0.01、0.02、0.03 and 0.04）were obtained by doping Zn²⁺.The results showed that the doping of Zn²⁺could decrease the specific capacity of the initial discharge,but the doping of Zn²⁺could improve the cycle performance and the ratio performance of the material.When the doping amount of Zn²⁺was 3%,the cycle performance and ratio performance could be improved better than other amounts.LiNi_0.8Co_0.1Mn_0.1O₂ was doped with different amounts of F^-to obtain Li Ni_0.8Co_0.1Mn_0.1O_2-yF_y（y=0.01、0.02、0.03 and 0.04）,and explored which amount of F^-doping can make the cathode material have best performance.The results showed that the initial discharge specific capacity of the Li Ni_0.8Co_0.1Mn_0.1O_1.98F_0.02 could reach 202.4m Ah·g^-1.Compared with undoped and other doping amounts,it had better cycle performance,rate performance and larger lithium ion diffusion coefficient.