Synthesis And Electrochemical Performance Of Metal Oxides For Energy Storage Electrode

In view of the increasing realization and efficient utilization of new energy resources,the new high efficiency,the developement of steady electric energy storage device become the main task in the modern word.Now,the study of a wide range of energy storage technologies includes lithium ion batteries and supercapacitors.Supercapacitors are the world leader in the technology of global supercapacitors,with world-leading innovative technologies and world-leading cost advantages.In recent years,the recognition degree of super capacitor in our country is gradually improved.With the popularity of portable electronic devices,the demand of lithium ion batteries with high energy density is increasing.To meet the needs of the next generation of optoelectronic devices,such as flexible screens,flexible smart electronics and wearable devices,the need for a variable power supply is increasingly important.High energy density,high power density,good cycling stability and flexibility are the key problems in the development of lithium ion batteries.My main work during the master's period is to conduct a detailed and in-depth study on the asymmetric liquid supercapacitor of tungsten oxide and the lithium manganese acid lithium battery.The main conclusions are as follows:1.Developed a hydrothermal synthesis method of seed layer to prepare WO₃ nano-rods,and a large,uniform growth WO₃ nano-rod on carbon cloth.This synthesis method is simple and quick and effective.2:WO₃ nanorods in neutral solution cycle stability:the main reason of the WO₃ nanorods in the process of circulation partly dissolved in 5 mol/L LiCl electrolyte,irreversible oxidation reaction and make the structure damage.By electric reduction processing method,the introduction of low-cost state tungsten,make its produce oxygen vacancy,to improve the carrier concentration,which can effectively inhibit the WO₃ nanorods irreversible oxidation reaction and the destruction of the structure,this kind of treatment method significantly improves the electrochemical properties of WO₃ nanorods.At 10 mV/s,the area capacitance value of the ER-WO₃ nano-rod is 403.5mF/cm²,which is 1.5 times the area capacitance of Air-WO₃?276.4mF/cm²?.After the cycle of 5000 cycles,the capacity of the ER-WO₃ nano-rod was 97.4%,which was much higher than the capacity of the Air-WO₃ nano-bar with a capacity of 51.74%.3:An asymmetric liquid supercapacitor with a working voltage of 1.8v was successfully assembled as a positive electrode and a LiCl liquid electrolyte using Air-WO₃ as the negative pole and ER-WO₃@MnO₂ as the anode and LiCl liquid electrolyte.4:For the preparation of manganese acid lithium materials using high temperature solid phase method,the synthesis temperature is 1000?,manganese acid lithium materials under the current density of 0.1 C,the specific capacity of Air-1000?electrode reached a maximum of50 mAh/g.5:We mainly improve the electrochemical properties of materials by means of nitrogen doping.Through the Air-1000?electrode doped with different nitrogen temperature contrast results show that 700?with temperature cycle stability of the electrode was one of the best and highest specific capacity value.The capacity retention rate reached a maximum of 67%when the current density of 0.2C was circulated to the 100th lap.Current density increase from 0.1 C to 5 C of the test results show that the doping of specific storage temperature is 700?electrode value is the highest.Therefore,the preparation of doped temperature is 700?of manganese acid lithium has optimal electrochemical performance.The improvement of electrochemical performance is mainly due to the doping of nitrogen elements,resulting in oxygen vacancy,which is transformed from LiMn₂O₄ to LiMnO₂.The cyclic stability and specific capacity of the double-layer LiMnO₂ were higher than that of the spinel LiMn₂O₄.