Abstract: Manganese acetate and ammonium persulfate used as raw materials,MnO₂ was prepared by hydrothermal synthesis method,and then MnO₂/CNTs composites was prepared by ultrasonic method.The products were characterized by X-ray diffraction,fourier transform infrared spectroscopy and scanning electron microscopy,and their electrochemical performances as cathode for AZIBs were measured by cyclic voltammetry,electrochemical impedance spectrum and galvanostatic charge-dicharge.The results showed that the product was β-MnO₂ nanowires at the reaction temperature of 140 ℃ and reaction time of 22 h.The chemical structure of β-MnO₂ did not change when it was compounded with CNTs.When circulated 20 times at 0.1C magnification,the first specific discharge capacity of β-MnO₂/CNTs electrode in 1 mol/L ZnSO₄+0.5 mol/L MnSO₄ aqueous solution is 140 mAh/g.Compared with the first discharge specific capacity of β-MnO₂/CNTs electrode in 1 mol/L ZnSO₄ solution (45 mAh/g),the first discharge specific capacity has been increased by 2 times;and compared with the first discharge specific capacity of β-MnO₂ electrode in 1 mol/L ZnSO₄+ 0.5 mol/L MnSO₄ aqueous solution (27 mAh/g),it has been increased by 4 times,which indicates that the composite of β-MnO₂ and CNTs can improve the electrochemical performance of β-MnO₂ Moreover,the electrochemical performance of β-MnO₂/CNTs electrode is better in 1 mol/L ZnSO₄+0.5 mol/L MnSO4 aqueous solution,but the capacity retention rate is only 50%,which indicates that the performances of the battery needs to be further improved.

Key words: MnO₂/CNTs composites, aqueous zinc-ion batteries, cathode material, electrochemical performance