Preparation Of Quinone-V₂O₅ Composites Cathode Material And Their Performance In Aqueous Zinc Ion Batteries

Aqueous zinc ion batteries（AZIBs）are expected to stand out in the next generation of large-scale power storage materials due to the lower cost of zinc metal and higher safety of aqueous electrolyte compared to lithium ion batteries.Currently,the main reason limiting the commercialization of aqueous zinc ion battery technology is the inadequate electrochemical performance of its cathode material.Vanadium pentoxide（V₂O₅）has received much attention from researchers due to its ability to provide a large number of Zn²⁺embedding/de-embedding sites when applied as an anode material with its layered structure.In addition,the wide range of organic quinones,easy to synthesis,high theoretical specific capacity,and various reaction sites also have high prospects for application in aqueous zinc ion batteries.In this work,a new quinone-V₂O₅ composite was developed by using organic quinones to modify V₂O₅,and its electrochemical performance as a cathode active material in aqueous zinc ion batteries was investigated as follows:The embedded 1,5-dichloroanthraquinone preinserted V₂O₅ composite（VA-1）was prepared by hydrothermal method and applied to aqueous Zn-ion batteries as a cathode material,based on the nanosized treatment of V₂O₅.1,5-dichloroanthraquinone composite expands the layer spacing of V₂O₅,which makes the layer structure of V₂O₅ cathode material more stable;meanwhile,the carbonyl C=O on 1,5-dichloroanthraquinone can become the active site for Zn²⁺embedding/exfoliation through thus enhancing the electrochemical performance of the V₂O₅ material.The prepared composite samples were examined using a series of characterization tools and electrochemical performance tests,and it was confirmed that the embedding of 1,5-dichloroanthraquinone had an improving effect on the electrochemical performance of V₂O₅.The aqueous zinc ion battery assembled using the composite had a first-cycle discharge capacity of 371.1 mAh g^-1 at 1mol L^-1 Zn SO₄ electrolyte with a current density of 0.02 A g^-1,which was about 30%higher capacity and improved cycling stability compared with the composite V₂O₅nanomaterial,especially better than p-benzoquinone,tetrachloroquinone and2,3-dichloro-1,4-naphthoquinone and V₂O₅ synthesized composites.To further enhance the electrical conductivity of the composites,in this paper,the prepared VA-1 was further compounded with reduced graphene oxide（rGO）.The prepared composite samples were examined using a series of characterization tools and electrochemical performance tests,and the presence of rGO was confirmed to be beneficial to the enhancement of the electrochemical performance of the composite cathode material.The aqueous Zn ion battery assembled using this composite as the cathode material had a first-turn discharge capacity of 367.1 mAh g^-1 at the same test conditions.Compared with the VA-1 cathode material,the first-turn discharge specific capacity decreased slightly,but after high-current charging and discharging,and then returning to a current density of 0.02 A g^-1,the electrode still provides a discharge specific capacity of 164.4 mAh g^-1,which compared with the VA-1 cathode material,the capacity is improved by about 100%.This indicates that the good electrical conductivity of rGO leads to a significant improvement in the electrochemical properties of the VA-1 cathode material such as cycling stability.