Study On Zinc Electrode Of Rechargeable Zinc-air Battery

Rechargeable zinc-air battery has high capacity, environmental friendliness and low price properties and so on. Zinc anode is one of the key technologies of secondary zinc-air battery. In this paper, we researched the rechargeable zinc electrode deeply in order to improve its electrochemical performance.The electrochemical properties of the zinc anode in different concentrations of KOH, saturated with ZnO, have been investigated. The zinc electrode has the highest capacity and the lowest hydrogen in the40%KOH solution.Adding additives to the electrode or the electrolyte can improve the properties of zinc anode. In this paper, we researched the effects of seavral additives on performance of zinc electrode.Adding different weight of OTAC to the electrolyte, the electroch-emical performance of the zinc anode have been tested. The results tell us that OTAC can accelerate zinc dissolution reaction, improve the anodic diffusion current and suppress the passivation of the zinc anode, and increase the utilization rate of zinc. The solution of0.7%OTAC has the best performance on suppressing the passivation, the utilization rate of zinc increased from51.8%to70.4%.TinO2n-1was prepared by high temperature reduction of TiO2-C36H70O4Ca and TinO2n-1were added to zinc electrode respectively. A cell was assembled with the prepared ZnO electrode as anode and nickel electrode as cathode. The effects of C36H70O4Ca and TinO2n-1on zinc electrode have been reaserched independently. After1,40,120cycles, the electrochemical properties of the secondary zinc anode have been investigated by anodic polarization curves and impedance spectra.The results express that the cell retained90%of its initial capacity from190cycles to300cycles after adding C36H7o04Ca. After120cycles, the current of the zinc anode is0.224A at the potential of o.l V vs. Zn/Zn(OH)2, however, that of blank electrode is0.042A. From the impedance spectra test, we find that C36H70O4Ca can suppress the passivation of the zinc anode.The cell containing2%C36H70O4Ca has the highest capacity, the lowest final charge potential, the highest median discharge potential and the longest cycle numbers from110to160at the rate of1C charge/discharge.TinO2n-1can improve the cycle numbers of the zinc anode remarkably. The cycle numbers increase130. After120cycles, the current of the zinc anode is0.297A at the potential of0.1V vs. Zn/Zn(OH)2, however, that of blank electrode is0.042A. From the impedance spectra test, we find that TinO2n-1can suppress the passivation of the zinc anode. We can also find that TinO2n-1can reduce the shape change and make ZnO and zinc loose and porous by SEM. The cell containing1%TinO2n-1has the highest capacity, the lowest final charge potential, the highest median discharge potential and the longest cycle numbers from90to160at the rate of1C charge/discharge.