Preparation And Modification Of High Capacity Nickel-based Cathode Material LiNi 0.8 Co 0.1 Mn 0.1 O 2

As a carrier of the information age in the future,new energy electric vehicles have increasingly high energy density requirements for power lithium-ion batteries.In addition,the shortage of raw materials such as cobalt metal also contributes to the development of high nickel cathode materials with higher energy density.Compared with other ternary cathode materials,Ni-rich cathode material Li Ni_0.8Co_0.1Mn_0.1O₂,owning higher specific discharge capacity,lower cobalt content,lower cost of materials while meeting the concept of environmental protection,has become the focus of multi-party chasing.However,the stability and safety issues of this material are more prominent.Therefore,based on the background of the vigorous development of new energy industry and the development trend of high-nickel cathode materials,the LiNi_0.8Co_0.1Mn_0.1O₂ cathode material was prepared and the preparation process,including Nb⁵⁺doping and SnO₂ adding,was optimized to improve the electrochemical performance.The materials was comprehensively characterized by modern testing methods such as XRD,SEM,TG-DSC,EDS,BET,and electrochemical performance tests.The specific study is as follows:The LiNi_0.8Co_0.1Mn_0.1O₂ was synthesized from the precursor Ni_0.8Co_0.1Mn_0.1?OH?₂ by co-precipitation and high temperature solid-state method.The results indicated that the spherical LiNi_0.8Co_0.1Mn_0.1O₂ through the best Sythesis condition can be obtained by calcining 10%excess amount of LiOH·H₂O and the precursor Ni_0.8Co_0.1Mn_0.1?OH?₂ preparing via co-precipitation under 1.0 mol/L ammonia at 800 ^oC for 12 h,which had uniform particle distribution and a complete structure can be identified to a typical?-NaFeO₂ stratified structure.At 25 ^oC,The material delieved an initial dischange capacity of 180.9 mAh/g under the voltage of 2.75⁴.2 V by 0.2 C rate,and capacity remained 88.89%after 100 cycles.In addition,the specific capacity of the material is 192.8 mAh/g with the capacity retention of76.87%after 100 times while cycle at 4.35 V.The Li(Ni_0.8Co_0.1Mn_0.1)_1-xNb_xO₂?x=0.01,0.02,0.03,0.04?cathode materials were obtained through different doping ratios of Nb.Nb doping did not change the layered structure but reduced the polarization effect of the battery as well as improved matericals cycle performance under normal temperature and high temperature.The initial discharge specific capacity of The Li(Ni_0.8Co_0.1Mn_0.1)_0.99Nb_0.01O₂ were 172.9 mAh/g and 159.7 mAh/g respectively when cycled between 2.75 and 4.2 V at 0.2 C and 1 C,and the capacity only decreased by 2.53%and 2.13%after 100 cycles.When the doping amount was x=0.01,the specific discharge capacity of the material was maintained at around 183 mAh/g when cycled for 20 rounds at 50 ^oC in the range of 2.75⁴.2 V with 0.5 C.The nano SnO₂ was added into the cathode material through a simple method,improving the cycle performance of the original material.And the addition of nano SnO₂ did not affect the layered structure of the host material.When the amount of SnO₂ adding was 3 wt.%,the specific discharge capacity of the material at 25°C was 187.5 mAh/g and 169.6 mAh/g respectively when charged between 2.75 and 4.35 V at 0.2 C and 1 C.After 50 cycles,the corresponding capacity retention can reach 90.77%and 87.43%.