Study On Modified α-MnO₂ And Organic Schiff Base As Cathode Electrode Materials For Aqueous Zinc-ion Batteries

At present,lithium-ion batteries（LIBs）are widely used in people’s lives,and they play a very important role in electronic products and micro-devices.However,problems such as higher cost and lower safety hinder the further development of LIBs.Compared with LIBs,zinc-ion batteries（ZIBs）have abundant reserves of metallic zinc in nature.In addition,the use of aqueous solutions as electrolytes makes aqueous ZIBs have the advantages of lower cost and higher safety,and has been favored by many researchers.However,this type of battery has relatively high requirements for the cathode material.The cathode material must have sufficient interlayer spacing to meet the intercalation and extraction of zinc ions.This makes the types of inorganic materials that can be used less,and the number of inorganic materials performance is not stable yet.This article starts from the cathode material of aqueous ZIBs and improves the electrochemical performance of the battery by modifying inorganic materials.In addition,organic compounds have the advantages of controllable structure,green and pollution-free.In addition,there are many types of functional groups,and there are many ways to store zinc ions.Only the rearrangement of chemical bonds occurs during the redox reaction,without changing the molecular structure.Looking for new organic materials as cathode materials for aqueous ZIBs,and exploring the ability of organic compounds to store zinc ions.Through the micro-control of Ni²⁺onα-MnO₂,it can be seen that the size of the material has a great influence on its performance.Based on this conclusion,the effect of one-dimensional,two-dimensional and three-dimensional Schiff base materials on its performance is explored.The specific content is as follows:（1）α-MnO₂ was synthesized via a hydrothermal synthesis route,and Ni²⁺was introduced in the reaction process to inhibit the excessive growth ofα-MnO₂material and optimize the particle size of the cathode material.The experimental results show that the synthesizedα-MnO₂+Ni₆ sample has the best electrochemical performance when 6 mmol Ni²⁺is introduced.α-MnO₂+Ni₆ electrode material has a specific capacity of 270 m Ah g^-1at the current density of 50 m A g^-1.At a high current density of 500 m A g^-1,the specific capacity of 110 m A g^-1 can be obtained,and the capacity retention rate of 65%can be obtained after450 cycles.Therefore,the cycling stability is good at a high current density,indicating that the electrochemical properties of the material can be improved by optimizing the particle size of the material by introducing inhibitors.（2）Schiff base is a kind of organic compound containing carbon nitrogen double bond,which is synthesized by using p-phenylene diamine,melamine,polyethylenimine and terephthalaldehyde as raw materials,respectively.After testing,it was found that one-dimensional Schiff base could not store zinc ions effectively due to the lack of functional groups and active sites in the molecule.Three-dimensional Schiff bases don’t any conjugated structures in nature,they have too much resistance and they don’t conduct well enough to store zinc ions.The two-dimensional Schiff base networks（SNW）has an obvious redox peak,which can store zinc reversibly.The SNW electrode material has a specific capacity of 70 m Ah g^-1 at a current density of 50 m A g^-1 and a 90%capacity retention rate after 100 cycles.