Study On Synthesis And Electrochemical Properties Of Nickel-rich Cathode Materials For Lithium Ion Batteries

In the face of increasing resource pressures and environmental crises,the development of renewable energy is considered to be a technical issue that needs to be addressed.Nickel-rich cathode material LiNi_1-x-yCo_xMn_yO₂ is the most potential candidate material for lithium ion battery cathode materials due to its high specific capacity.Therefore,there has great significance research on high-energy battery materials.In this work,the precursor Ni_0.8Co_0.1Mn_0.1?OH?₂ was produced by coprecipitation method with NiSO₄·6H₂O,CoSO₄·7H₂O and MnSO₄·H₂O as raw material.After mixing with LiOH·H₂O,it was sintered by high temperature solid phase method to obtain lithium ion battery cathode material LiNi_0.8Co_0.1Mn_0.1O₂.LiNi_0.8Co_0.1Mn_0.1O₂was used as the research material,improved synthesis conditions.And to improve the stability of nickel-rich material LiNi_0.8Co_0.1Mn_0.1O₂ was doped by Ti⁴⁺or Zr⁴⁺were investigated.Through the study of the optimum process conditions for the synthesis of LiNi_0.8Co_0.1Mn_0.1O₂ materials,the effects of different sintering temperatures,different sintering time and excess lithium ratios on the materials were investigated by XRD,SEM,charge and discharge performance test and CV.The results explained that the electrochemical performance of the positive electrode material LiNi_0.8Co_0.1Mn_0.1O₂obtained by sintering at 750°C for 12h is best relatively with Li/TM?Ni+Co+Mn?=1.10:1.In the cutoff voltage range of 2.5 to 4.3 V,the initial discharge capacity of the material was 183.8mAh/g at 0.5 C and the capacity retention was 90.9%after 50 cycles.In order to further improve the electrochemical properties of the materials,the LiNi_0.8Co_0.1Mn_0.1O₂ materials doped with Ti⁴⁺or Zr⁴⁺single elements were studied.The results explained that the material has the most excellent cycle stability and rate performance when the amount of doped TiO₂ is 1.25%.The first specific discharge capacity of the material is 181.5mAh/g and the capacity lost only 4.9%after 100 cycles.The effects of doping ZrO₂ at 1%,2%and 3%on Li(Ni_0.8Co_0.1Mn_0.1)_1-xZr_xO₂cathode materials were investigated.The XRD results show that the Zr⁴⁺doped materials does not affect the overall structure of the material.It was found that compared to the undoped LiNi_0.8Co_0.1Mn_0.1O₂ material.The material has better discharge specific capacity and cycle stability when the doping amount was 2%,which had a specific discharge capacity of 193.5mAh/g in voltage range of 2.5 to 4.3 V at 0.5C,and the capacity retention was 92.9%after 50 cycles.