Preparation And Performance Study Of High Nickel Ternary Cathode Material LiNi_0.8Co_0.1Mn_0.1O₂

Li(NixCoyMn2)O2 cathode material has become one of the most promising lithium ion cathode materials due to its low cost,high specific capacity and stable chemical structure.The increase of Ni helps to increase the specific capacity of materials.Therefore,the development of nickel-rich NCM cathode materials is currently the trend to increase the energy density of cathode materials.However,nickel-rich NCM materials also have a series of problems such as severe cation mixing,structural instability and rapid capacity fading.In view of those above problems,the effects of the synthesis conditions of precursor Ni0.8Co0.1Mn0.1(OH)2 on the morphology and electrochemical performance of the material were investigated.Therefore,the nickel-rich NCM cathode material can improve the cycle performance and rate performance of the material on the basis of high specific capacity.This has practical significance for the application and development of high-nickel NCM cathode material.The nickel-rich Ni0.8Co0.1Mn0.1(OH)2 precursor used NiSO4·6H2O,CoSO4·7H2O and MnSO4·H2O as the raw materials and synthesized by co-precipitation method in this paper.The morphology of the precursor material causing by reaction time,aging time,pH and water bath temperature during the coprecipitation reaction was investigated.Then explore the impact on the electrochemical performance of assembled batteries after the precursor calcined with lithium.The microstructure and electrochemical performance of the materials were characterized by XRD,SEM,ICP-AES and electrochemical workstation.It was found that,the reaction time and aging time do not affect the composition of the material,but the influence of the primary and secondary particles on the material is different at each stage.The increase in pH caused the morphology of the particles become to irregular small particles which could not form a regular spherical-like secondary particle morphology.The relationship between the water bath temperature and the morphology of the material is found to be closely related to the nucleation and growth pattern of primary and secondary particles.The results showed that pH=10,tempertature of water bath T=60℃ was the best condition for the precursor which has a regular spheroidal morphology and the best electrochemical performance after calcined.The discharge specific capacity is up to 194 mA·h·g-1 and 134 mA·h·g-1 at 0.2 C and 5 C,respectively.The initial coulombic efficiency is 87.57%at 0.2 C.