Oxygen Electrode Catalyst And Rechargeable Zinc - Air Battery Technology Research

The bifunctional oxygen electrode catalyst is the one of key problem of secondary zinc-air battery. Additionally, the structure of air electrode and zinc electrode have a great influence on zinc-air battery.In this article, the preparation of the catalyst, air electrode and the current collector of zinc electrode were studied and explored systematically. The perovskite type oxides LaNi0.8Co0.2O3 was prepared by the improved sol-gel method. XRD, SEM and TEM were employed to characterize the prepared catalysts.The polarization curves, electrochemical impedence spectroscopy methods and the galvanostatic discharge curves were used to study the electrocatalytic performances of the prepared catalyst in 7 mol/L KOH solution.The perovskite catalyst was prepared by the improved sol-gel method, the graphite was added into precursor by the molar ratio of all metal ion to the graphite was 1:1.The catalyst was prepared under different calcination temperatures, The results showed that the catalyst had the lowest agglomerates and the best electrochemical performance at the calcination temperature of 500℃. The oxygen reduction current density was 230mA·cm-2 at the electrode potential of -0.4V(vs.Hg/HgO). When the solvent was mixed by glycol and acetone instead of deionized water, The catalyst was prepared at the calcination temperature of 600℃, the grain diameter could get to 20-30nm and the oxygen reduction current density was 273mA·cm-2 at the same condition, respectively, a series of factors were considered during preparing process.The best composition of the rechargeable air electrode was established. The acetylene black was applied as the gas diffusion electrode carrier. In the catalysis layer, the best quality ratio of the component of PTFE, acetylene black and catalyst was 1:1:2. When adding 16.7%wt lead acetate as pore forming material, the best quality ratio of PTFE and acetylene black was 7:3 in the waterproof layer, the lead acetate was added in the mass ratio of 4.7% of the waterproof layer. Finally, the component of air electrode were arrayed as catalysis layer/ current collector/waterproof layer.The preparation technology of the rechargeable zinc-air battery was analyzed. The air electrode has the best oxygen evolution property if the foamy nickel as a auxiliary electrode. The lead plating copper as the current collector of zinc electrode can decrease hydrogen corrosion remarkably. The zinc-air battery was fabricated, the discharging and recharging number of the battery attained 35 times when the galvanostatic discharge current was 10A and galvanostatic charge current was 5.3A.