Modification And Charge/Discharge Performance Of Li_1+xNi_0.83Co_0.12Mn_0.05O₂ Cathode Powders

The residual alkali amount of high nickel material（lithium carbonate,lithium hydride）is extremely high.Agglomeration occurs when the battery is pulled by the battery.This is a difficult problem,and there are problems such as poor cycle life,which severely limits the high-nickel ternary material in the lithium battery.Effective application in production enterprises.In this paper,Li_1+x+x Ni_0.83Co_0.12Mn_0.05O₂ powder was used as the research object,and the best preparation process of Li_1+x+x Ni_0.83Co_0.12Mn_0.05O₂ powder,the effect of doping and coating modification on the structure and charge/discharge performance were studied.Ni_0.83Co_0.12Mn_0.05（OH）₂ was prepared by chemical co-precipitation method and mixed with LiOH·H₂O.The high temperature calcination was used to synthesize Li_1+x+x Ni_0.83Co_0.12Mn_0.05O₂ powder.The results show that the process precursor and batch are continuous.The positive electrode powder prepared by the process precursor shows good charge/discharge performance.The continuous process precursor has more small-sized secondary particles,and the positive powder prepared by the continuous process precursor precursor has better rate performance,cycle performance and compaction density.When x=0.04,calcination at 500^oC for5h and calcination at 790^oC for 12h,the optimal layered structure.when Li_1+x+x Ni_0.83Co_0.12Mn_0.05O₂ powder prepared at 3.0⁴.3V,0.1C rate,the lower discharge capacity can reach 206.6 mAh/g,and the 50-turn cycle capacity retention rate is 85.9%.The Li_1.04Ni_0.83Co_0.12Mn_0.05O₂ powder was doped with 2mol.%Al³⁺,Zr⁴⁺or Ti⁴⁺.The experimental results show that the structural characteristics of the material are not changed by the doping of Al³⁺,Zr⁴⁺or Ti⁴⁺.Cell parameters and SEM confirmed that the cation was doped into the crystal lattice.The powder discharge capacity of doped Al³⁺and Zr⁴⁺decreased,but the cycle performance was more excellent.The capacity retention rate was as high as 90.5%and 91.3%after circulating for 50 cycles at 1C/1C rate.Although doping of Ti⁴⁺does not reduce the discharge specific capacity of the material and improve the cycle performance,but it improves the rate performance of the material.The Li_1.04Ni_0.83Co_0.12Mn_0.05O₂ modified powder with B₂O₃ coating amount of0.3wt.%,0.5wt.%and 1.0wt.%was synthesized by wet coating,and the coated powder was found by XRD analysis.The crystal structure does not change due to coating.It can be clearly seen by SEM,EDS and TEM analysis that B₂O₃ is coated on the surface of the particles and distributed uniformly.The specific discharge capacity and cycle performance of the material coated with B₂O₃ were significantly improved.The Li_1.04Ni_0.83Co_0.12Mn_0.05O₂ coated with 0.5wt.%B₂O₃ had the best cycle performance,and the 0.1C discharge specific capacity was 210.5mAh/g.The first efficiency was 92.8.%,50 cycle capacity retention rate of 96.4%,an increase of nearly 10%.