Zinc - Air Battery The Air Electrode Study

The alkaline zinc-air battery, as an environmentally friendly electrochemical power sources for electromotive cars, has recently been attracted considerable attention because of a variety of advantages of the battery, such as high specific energy, flat discharge voltage and low cost of raw materials. Air electrode is extensively equipped in zinc-air battery, and the two main factors of electrode performance influenced, which were mainly researched in this article, are the oxygen reduction electrocatalyst and the structure of air electrode. The major results and conclusions are summarized as follows:Air electrode: AgNC>3 + (catalyst), PTFE, copper network etc.Reference electrode: Hg/ Hg OElectrolyte: 30%NaOHA semi-cell model was composed of the above three electrodes.The optimum condition for air electrode preparation were given as follows: PTFE content in the electrode layer was 35 wt %, the collecting current net was the copper network of aperture 147 mm, the thickness of the electrode layer was in 0.3mm, the electrode layer was sintered at 350 C, and the electrode layer was soaked in acetone for 8 hours at least to waterproof. The air electrode was composed of catalyst layer, the collecting current net and waterproof layer, which sequence in turn was diffusion layer, active layer, collect current collector net. The compacting pressure was 26MPa.2. Active carbon is the catalyst carrier, which was related to electrode performance. Air electrode is porous. The hole in air electrode was a key factor to the electrodes performance. Optimizing active carbon by sieving was the very essential, in the one hand, which improved transmitting route, in the other hand, which have the effective areas of catalyst increased. Sieving pretreatment for 300 eyes was optimum.The organic chemicals had the electrode performance dropped, when it was introduced in the procedure of electrode preparation, which should be solved primarily when air electrode was prepared by microemulsion technology. Generally speaking, Electrode performance was improved by washing the active charcoal. Effect of organicmatter on electrode performance was in order: n-Butanol + Xylene +Dodecyl benzene sulfonic acid sodium salt(DBS) > Ethanol > DBS. Because organic chemicals influenced the electrode performance in order, washing solvent was concluded to influence the electrode performance, too, which deserved probing into deeply and systematically. Polarization curves of electrodes using active carbon pretreated with different organic chemicals showed that voltages of electrode with active carbon pretreated with microemulsion change the most sharply. That is to say, microemulsion influenced the electrode performance mostly.4. The question solved primarily was to choose the proper solvent to wash the active carbon loaded catalyst, when catalyst was loaded with microemulsion technology. In the general, wishing solvents are the ethanol. The microemulsion was composed of the volume of CoCl2 solution 3.0ml, Xylene 7.0ml, DBS 4.0ml, n-Butanol 60 ml, NaOH solution 4.0ml. The mass of CoO loaded was 7.0 mg or so, which equaled with the quantity of the silver loaded, furthermore, the electrode performance was close. Loading catalyst with microemulsion technology was feasible to the air electrode preparation.