Zinc-air Battery Air Electrode Catalyst Preparation And Application

The perovskite catalyst was prepared by sol-gel method with malic acid as the precursor, and improved the processes on the basis of the methods that the activated carbon with certain ratio was added into solution respectively while it became the coffee color colloid and adjusted solution pH value at first. The structures of the catalysts were characterized by XRD and TEM, open circuit voltage, electrochemical polarization curves, AC impedance and charging and discharging electrochemical properties of air electrodes had been tested. In addition, compared electrochemical performances of the air electrodes that made by the method of combining heating roll pressure with cold pressure with that prepared by the method of rolling pressure and cold pressure. Effect of different quality of component of the catalysis layer and gas diffusion layer on performances of air electrodes had been studied deeply respectively. The results are shown as follows:(1) On the basis of sol-gel method, activated carbon (activated carbon: all cation with mol proportion 1:1, 3:2 and 2:1) wasn't added into the colloid respectively untill solution become coffee color colloid, and contrasted with the catalyst without improving by addition activated carbon, the results showed that improved perovskite catalyst have more tiny hole and distribute homogeneously, the air electrodes prepared by them have better performances than perovskite catalys without improving. Besides, perovskite catalysts improved by addition activated carbon (activated carbon: all cation with mol proportion 3:2) have best catalysis efficiency.(2) Improved perovskite catalyst prepared based on sol-gel methods by increasing solution pH value to 3～4, 5～6 and 9～10 at first respectively, the results indicated that cathode polarization current density increased from 0.2428 A·cm^-2 to 0.3832 A·cm^-2 , anode polarization current density augmented from 0.1229 A·cm^-2 to 0.3666 A·cm^-1, impedance decreased from 0.39269Ω. to 0.37445Ω, and lowered the speed of carbon corruption while discharging with solution pH increased.(3) Meanwhile, activated carbon, acetylene black, PTFE, catalyst is made up of the catalysis layer, and acetylene black, Na₂SO₄, PTFE is comprised to the gas diffuse layer. The results showed that the best quality ratio of the component of catalyst layer, activated carbon: acetylene black: PTFE: catalyst turned out to be 60:10:20:5; and the proportion of the component of gas diffusion layer, acetylene black: Na₂SO₄: PTFE proved to be 100:75:80 by testing electrochemical performances; current density of air electrodes prepared by this means is the biggest, charging and discharging properties of the simulation battery which composed with zinc anode and air cathode had been studied. The results indicated that charging and discharging cycle of the simulation battery attained more than 30 times, and the color of electrolyte changed from colorless to brown.