The Research Of Preparation And Electrochemical Properties Of Chromium Molybdenum Iron Zinc Lithium Oxide

Lithium-ion battery,as one of the energy storage equipment,has the advantages of large capacity,small volume,green environmental protection,easy to carry and so on.It has become a widely concerned energy storage equipment.In the battery cathode materials of iron compounds because of relatively low price,wide source and rich content etc,LiFePO4 material is the most potential one of the LiCoO2 material instead of commercialization.However,during the process of synthesis,iron is easy to oxidize,resulting in poor cycling performance of materials,which is the main reason for further restricting the commercialization of LiFePO4 materials.In this paper the lithium iron phosphate cycle performance is poor,by doping and synthesis process improvement,improve the capacity and cycle performance of LiFePO4 material.And the materials of electrochemical test and phase characterization and morphology etc.In the first chapter of this article,we will elaborate on the assembly of the battery that works on the lithium ion battery.It introduces the structure of the LiFePO4,and analyzes the main causes of the attenuation of the material,and analyzes the corresponding improvement methods in detail.In the second chapter,the assembly of the battery is described in detail.The third to fifth chapters mainly introduce the different proportions of positive materials prepared by coprecipitation method,and analyze the cycle performance of the materials,the first Kulun efficiency and the first charging capacity.In Fe(NO3)3 · 9H2O,(NH4)6Mo7O24 · 4H2O and Cr(NO3)3 as raw materials,(NH4)2CO3 as precipitant by liquid phase coprecipitation of chromium molybdenum oxide lithium ferrochromium in different proportion of synthesis.The charging and discharging test of the materials and the SEM test showed that the circulating performance of the material Li3CrMoFeOx was the best,the first coulomb efficiency and the charging capacity of the material are 77.3%,104.9mA·h/g respectively.The XRD test shows that the crystallinity of the different chromium iron proportional cathode materials is different,but the structure is not changed.On this basis,the material Li3CrMoFeOx was doped with Li bit,and the positive material Li3-aNaaCrFeMoOx(a = 0.1,0.2,0.3,0.4)was prepared.The charge and discharge tests showed that the cycle performance of thematerial was the best,the first coulomb efficiency and the charging capacity reached 85.9%,118.4mA h/g respectively,After 20 charge and discharge,the capacity was 79.0mA·h/g.Using ZnO,HNO3 and Cr(NO3)3 as raw materials and(NH4)2CO3 as precipitant,lithium chromium zinc oxides with different chromium and zinc ratios were synthesized by liquid phase coprecipitation.Charge and discharge and XRD and SEM tests showed that the circulating performance of the prepared material Li2CrZnOx was the best,and the first coulomb efficiency and the charging capacity were 80.8%,104.0mA·h/g respectively.Using Fe(NO3)3 · 9H2O,ZnO,Al2O3,(NH4)6Mo7O24 · 4H2O and Cr(NO3)3 as raw materials and(NH4)2CO3 as precipitant,a coprecipitation method was used to prepare chromium molybdenum zinc iron aluminum lithium oxide,and the effect of reduction temperature on material properties was studied.The optimum reduction temperature of the cathode material Li4.03CrMoFeZnAl0.03Ox is 750?,the first coulomb efficiency and the charging capacity are 88.9%,142.4mAh/g respectively,the reduction temperature is 750? from the elevation to 870?,the capacity of the cathode material Li4.03CrMoFeZnAl0.03Ox is lower and the activity of the material decreases.