Research On The Preparation And Doping Co Of LiNi_0.5Mn_1.5O₄ Cathode Material For High Voltage Lithium-ion Battery

Lithium ion battery cathode material LiNi0.5Mn1.5O4 has the advantages of high voltage,high energy density,to make it in the field of power lithium ion battery has a good application prospect.We study the three different conditions of coprecipitation preparation LiNi0.5Mn1.5O4 material,through comparing morphology and discharge capacity,finally determine the use of carbonate coprecipitation preparation(pH = 7.5)LiNi0.5Mn1.5O4 material,LiNi0.5Mn1.5O4 material has the adventages of high purity,large discharge specific capacity,suitable for mass production.To get the optimal LiNi0.5Mn1.5O4 material preparation technology,we studied respectively from the following three aspects.First of all,respectively in three different lithium source(LNMO-Li2CO3,LNMO-LiOH,LNMO-CH3COOLi)among them,LNMO-Li2CO3 has the good rate of dischargeeablity and cycle performance,and keeping the precursor good spherical shape,the smaller particle size,specific surface area is big,short diffusion path of the lithium ions and electrons.To optimize the preparation process of LiNi0.5Mn1.5O4 samples,the initial discharge capacity of LiNi0.5Mn1.5O4 increase with the increase of the amount of lithium,including LNMO-1.0 the good rate of dischargeeablity of the sample performance is good,loop performance is stable,and its electrochemical activity is highest.Li Ni0.5Mn1.5O4 material has two kinds of space group structure,with the annealing temperature is gradually reduced,Fd3 m unordered space group structure will be to P4332 orderly space group,LNMO-b sample,from650 ? to 0.5 ?/min natural annealing temperature to 400 ? and then samples,has the best performance and good cycle performance.Co doping can decrease the lithium ion diffusion barrier,improving the conductivity of the lithium ions and electrons,shortening the lithium ion diffusion path,the research results show that the Li Ni0.5Mn1.5O4 Co doping can make its cyclical and m1 times willfulness have greatly improved,but the Co doping can reduce LiNi0.5Mn1.5O4 material initial discharge specific capacity,and comprehensive consideration,LiNi0.527Mn1.62Co0.022O1-y material cycle performance is best.In addition,the preparation of the Mn1.5Co1.5O4 anode materials,due to its unique microstructure and microstructure,can fully contact with the electrolyte,the(hierarchical structure)on the layer classification of the microstructure can provide shorter lithium ion diffusion path,reduces the volume change of materials in the process of charging and discharging,make excellent electrochemical performance.Finally,using LiNi0.5Mn1.5O4 anode materials and the Mn1.5Co1.5O4 anode materials to assemble the whole battery,LiNi0.5Mn1.5O4 current limiting the anode materials,get all the battery of the discharge specific capacity is very high,can reach 100 mAh g-1.Although not as good as the anode material,the dischargecapacity of 130 mAh g-1,but for LiNi0.5Mn1.5O4,all batteries,battery resistance is big,all lead to the discharge capacity and cycle performance than half cell.