Controllable Preparation And Lithium/Zinc Storage Performance Of Zinc-based Oxides

Due to the rapid development of the global economy and the continuous growth of the population,the demand for energy in human society is also increasing.Therefore,the development of high-efficiency,low-cost,renewable and environmentally friendly new energy sources is extremely urgent.Among them,the secondary battery has become the most concerned research object due to its higher energy density.With the rapid development of portable electronic devices and electric vehicles,the demand for secondary batteries is gradually increasing.Therefore,it is very necessary to improve the energy density and cycle life of secondary batteries.As we all know,electrode materials will directly affect the electrochemical performance of secondary batteries,so this paper prepared three materials and explored their applications in a variety of energy storage devices,such as lithium-ion batteries and zinc-ion batteries.The main results are as follows:（1）Using zinc acetate as the zinc source,C₃H₆O₃Zn microspheres composed of two-dimensional nanosheets were obtained through a simple solvothermal process.By adjusting the reaction conditions,we can adjust the size and structure of the C₃H₆O₃Zn.C₃H₆O₃Zn solid microspheres of different sizes can be obtained by controlling the amount of zinc source,and C₃H₆O₃Zn soild/hollow microspheres can be obtained by changing the reaction time.C₃H₆O₃Zn soild/hollow microspheres can be converted into Zn O soild/hollow microspheres by heat treatment.Using Zn O solid microspheres and Zn O hollow microspheres as anode materials for lithium-ion batteries,respectively,the study found that after 200 cycles at a current density of200 m A g^-1,the specific capacity of Zn O hollow microspheres is still as high as 485.3m Ah g^-1.Obviously,Zn O hollow microspheres have better electrochemical performance as anode material for lithium-ion batteries than Zn O soild microspheres.This is mainly due to its unique hollow structure can be used as an electrolyte storage tank,which is conducive to ion diffusion and increases active sites.（2）Using the above obtained C₃H₆O₃Zn solid microspheres as the zinc source and ammonium vanadate as the vanadium source,Zn₃（OH）₂V₂O₇·2H₂O nanosheets were synthesized in an oil bath.Zn₃（OH）₂V₂O₇·2H₂O nanosheets were heat-treated in air atmosphere to obtain Zn₃V₂O₈ nanosheets.Using Zn₃V₂O₈ nanosheets as anode material for lithium-ion batteries,the study found that after 200 cycles at a current density of 200 m A g^-1,the specific capacity of Zn₃V₂O₈ nanosheets is still as high as662.0 m Ah g^-1.Compared with the single metal oxide Zn O,the bimetal oxide Zn₃V₂O₈ nanosheets have better electrochemical performance as anode material for lithium-ion batteries.The excellent electrochemical performance of Zn₃V₂O₈nanosheets is mainly attributed to the synergistic effect of various metal ions of Zn₃V₂O₈.（3）We use ion pre-intercalation strategy to prepare Zn_0.54V₂O₅ by pre-intercalating Zn²⁺between the V₂O₅layers.The results show that Zn_0.54V₂O₅ has excellent cycle stability as zinc ion battery cathode material.After 2000 cycles at a current density of 10 A g^-1,the specific capacity of Zn_0.54V₂O₅ is still as high as 237.8m Ah g^-1.The excellent electrochemical performance is mainly attributed to the pre-insertion of Zn²⁺which stabilizes the V₂O₅ layered structure and ensures its structural stability during the cycle,thereby improving the cycle stability of the battery.