Study On Preparation And Modification Of Nickel-Cobalt Aluminum LiNi_0.8Co_0.15Al_0.05O₂ Cathode Material

Ternary high nickel LiNi_0.8Co_0.15Al_0.05O₂ cathode material with high capacity and magnification performance,the cost is relatively low,there is a good application prospects.In this paper,Ni_0.8Co_0.15?OH?_1.9precursor was prepared by coprecipitation controlled crystallization method.Spherical LiNi_0.8Co_0.15Al_0.05O₂ was prepared by high temperature solid phase doping of aluminum nitrate and lithium carbonate.The results as:The better conditions was as follows:ammonia concentration 1.2mol/L,pH value 11.0-11.1 and reaction time 20h.Under this condition,synthesized cathode material has good electrochemical performance.50? calcined16h LiNi_0.8Co_0.15Al_0.05O₂ material cation separation degree is low,while the spherical shape and shape structure is better.The discharge capacity at the 0.2C,0.5C,1C,2C and 5C magnifications is 180.1,163.3,156.9,148.5and139.8mAh/g at room temperature,respectively,and the capacity retention rate is 81.12%at 0.5C magnification.CV curve obtained from the lithium ion prolapse and embedded diffusion coefficient DLi were 2.72 × 10^-11 and 1.41 ×10^-11cm2/s.The EIS test shows that with the increase of the number of cycles,the damage of the SEI film on the electrode surface leads to the increase of the interface impedance and the charge transfer impedance,and the cyclic performance of the material decreases.Preparation of LiNi_0.8Co_0.15Al_0.05O₂ Cathode Material by Sol-Gel Method and High Temperature Calcination Synthesis of Nano-ZnO XRD analysis showed that the amount of ZnO modified by different mass fraction had no effect on the structure of LiNi_0.8Co_0.15Al_0.05O₂ cathode material,and Zn²+ did not enter the interior of the material.SEM and TEM show that ZnO is evenly distributed in the material to indicate that the particle size is 50-200 nm while the crystallinity is also very good.The performance and magnification of the material after modification of ZnO are greatly improved,When the amount of ZnO is 1 wt%,the cycling performance of the material is the best.At a rate of 0.2C and 3 0-4.3 V,the capacity retention rate was 92.2%and the capacity retention rate of the initial sample was 80.9%.Indicating that modified ZnO can improve the cycle performance of materials.The maximum discharge capacity of the N1 samples increased by 4.56%and 7.53%at 2C and 5C magnification,respectively.It can be seen that the ZnO modification can improve the discharge performance of the materials.Cyclic voltammetry 'was performed by1wt%of ZnO-modified samples at corresponding positions of 3.31 ×10^-11and 1.52 ×10^-11cm²/s,respectively.The lithium ion diffusion coefficient of the modified sample is higher than that of the original sample,which is consistent with the previous analysis.EIS test ZnO particle modification significantly reduces the charge transfer resistance and SEI membrane resistance,so that the electrode's electronic conductivity and surface stability.