Research Of Vanadium-Based Aqueous Zinc-ion Batteries

Aqueous zinc-ion batteries（ZIBs）have gradually developed the potential for electrochemical energy storage owing to low cost,environmental friendliness and high safety.In view of this,a lot of research work is devoted to the design and development of high-performance ZIBs.However,there are still many problems such as the poor cycling of cathode,the generation of by-products,the unclear reaction mechanism,zinc dendrite.Herein,the cathode,anode and electrolyte are improved to overcome the obstacles,and XRD,SEM,TEM,TG were performed.The main results are shown as follows:（1）Nanorod-like vanadium oxide was prepared by a one-step hydrothermal method.The effects of molar ratio of potassium sulfate and oxalic acid and different hydrothermal time on the morphology of K⁺intercalated vanadium oxide were investigated.In addition,the K_0.54V₂O₅nanorods with several microns in length and tens of nanometers in width were synthesized.The material displays an excellent electrochemical performance,with a capacity of 176 m Ah g^-1over 2400 cycles at 5 A g^-1,corresponding to a capacity retention of 97%.Finally,the interlayer variation of K_0.54V₂O₅during the charge-discharge cycle was analyzed.（2）Acetyl acetone was used as an electrolyte additive.The symmetric Zn||Zn battery was assembled by using 2 M Zn SO₄and different concentrations of acetyl acetone mixed electrolytes.The effects of the performance,electrochemical impedance,Zn corrosion and Zn dendrite were explored.Compared with 2 M Zn SO₄electrolyte,the life of Zn symmetric battery with acetyl acetone electrolyte additive was increased to 367 hours.In addition,the full battery with commercial V₂O₅and acetyl acetone used as cathode and electrolyte additives also displays outstanding electrochemical performance.The highest discharge specific capacity reach 146 m Ah g^-1at the current density of 5 A g^-1,and the capacity retention rate is 96%.（3）Carbon oxide nanotubes are used as a protective layer on the surface of zinc foil.The performance and electrochemical impedance of symmetric Zn||Zn battery were investigated.The experimental results show that the Zn anode coated with carbon oxide nanotubes has excellent cycling stability in the process of plating and stripping.Compared with bare zinc foil,the life of Zn symmetric cell modified with carbon oxide nanotube coating increased to more than 2350 hours.Finally,a suitable carbon material as zinc anode protective layer was got.