Synthesis Of Vanadium Oxide Based Nanomaterials And Its Application In Aqueous Zinc Ion Batteries

In recent years,secondary batteries mainly based on lithium ion batteries have been widely used in consumer electronics,new energy vehicles and various energy storage fields.However,the shortage of lithium metal resources and the flammable and explosive nature of organic electrolytes limit the future development of lithium-ion batteries.As a new type of secondary battery,aqueous zinc ion battery has attracted wide attention due to its unique advantages.First,compared to organic electrolytes,aqueous electrolytes are safer,cheaper,and have higher ionic conductivity.Secondly,the metal zinc anode has the advantages of high natural abundance and stable existence in water.Although the current research on water-based zinc ion batteries has made some progress,there is still little research on cathode materials with high capacity,high rate performance and long cycle life.Therefore,in this paper,three vanadium oxy based compounds are used as research objects,which are used as cathode materials to assemble aqueous zinc ion batteries,and their electrochemical performance and energy storage mechanism are studied respectively.The main research contents of this article are as follows:The Na_1.25V₃O₈ nanosheet cathode material was prepared by the sol-gel method.The assembled zinc ion battery has a high voltage window of 0.2-1.9 V.When the power density is143.6 W kg-1,the maximum energy density can reach 416.9 Wh kg^-1.In the study of its energy storage mechanism,ex-situ XRD and XPS test shows the phase transition process of Na ion desorption from the electrode in the first charge and discharge cycle.The Zn₃V₂O₇?OH?₂·H₂O nanosheet positive electrode material was prepared by hydrothermal synthesis method.The assembled zinc ion battery showed excellent rate performance,and the capacity retention rate can be up to 81.7%at 10A g^-1.After 6000 cycles under a large current density of 5 A g^-1,an extremely long cycle life can be obtained with capacity retention rate of 94.4%.DSCV analysis results show that the excellent cycling performance of the electrode is due to the stable structure in the cycles.The?NH₄?₂V₆O₁₆·1.5H₂O nanobelt cathode material was prepared by hydrothermal synthesis method,assembled into a zinc ion battery and electrochemically tested.The results show that the electrode has a high initial capacity of 515.3 mAh g^-1 and excellent rate performance.It still has a reversible capacity of 183.3 mAh g^-1 at a high current of 10 A g^-1,and the energy density at a power density of 527.3 W kg^-1 can be up to 505.0 Wh kg^-1.At the same time,ex-situ XRD results indicate that new phases are generated during the cycling process.