Preparation And Performance Research Of Vanadium-based Aqueous Zinc-ion Battery Cathode Material

Li-ion batteries(LIBs)have attracted a lot of scientific and technical interest in energy storage,due to their high energy density among rechargeable batteries.However,the high cost,limited lithium reserves,and poor safety make it hard to scale up LIBs.Aqueous rechargeable zinc-ion batteries have recently been attracted due to their safety,economy,high energy density,long cycle life,etc.The research was focused to developing cathode materials which can make full use of their electroactive materials.In this paper,three different vanadium-based materials have been prepared,which can be combined with different carbon materials or doped with Co to improve the zinc ion transport characteristics of the materials and improve the electrochemical performance of the materials.The research content is mainly the following three aspects:1.V₆O₁₃@HCMs composites synthesized via high-temperature magnetic stirring and sintering method,and used it for aqueous ZIBs.The V₆O₁₃layer is uniformly coated on the surface of the hollow carbon microspheres(HCMs)to form the hollow core-shell structure.The increase in HCMs and thinner V₆O₁₃layer improves the electrochemical stability of V₆O₁₃@HCMs.V₆O₁₃@HCMs-2 are excellent cathode materials with high specific capacity(442.3 m A h g^-1at 0.1 A g^-1)and good cycling stability(162.1 m A h g^-1after 1000 cycles at 1.0 A g^-1).V₆O₁₃@HCMs can not only provide efficient pathways for the transfer of electrons and Zn²⁺,but also reduce the volume change during the Zn²⁺insertion/extraction processes.2.The V₂O₅and graphene composite was synthesized by a facile freeze-drying and sintering process as a novel ARZIB cathode material.Specifically,the burr-like structure and smaller grain size of the V₂O₅-C101 can supply more active sites,and have strong structural stability,which leads to good electrochemical performance.The Zn//V₂O₅-C101 battery delivers a high capacity of 418.7 m A h g^-1at 0.1 A g^-1and a good long cycling stability(76.5%capacity retention after 1000cycles at 2 A g^-1).3.Co in the ternary material of lithium-ion battery can stabilize the layered structure of the material,and can improve the cycle and rate performance of the material.We synthesize the Co-doped NH₄V₄O₁₀material through a simple one step hydrothermal method,and studied the NH₄V₄O₁₀material with the best doping degree.the results show that the NVO-Co/2 material doped with Co to V molar ratio of 2%shows better electrochemical performance,it showed a high discharge specific capacity of 398.3 m A h g^-1at 0.1 A g^-1,and the capacity retention rate was83.4%for 1000 cycles at 1.0 A g^-1.