Application And Performance Of The Air Electrode

Air electrode is an important part of metal-air battery and some electrochemical reactor. It's researched several technique factors influencing the performance of air electrode and established the optimum preparing technics, which is applied in practice, in this paper.The results show that heat treatment strongly improves the performance of air electrode. The optimal heating temperature is at about 340℃. Under 340℃,along with the increase of heating temperature, electrochemical performance of air electrode is obviously improved; but heat treatment above 340℃ will lead to the performance decreasing. There are compact and homogeneous micro-pores in the electrode made by this technique. Electrochemical performance and life of air electrode are all greatly increasing due to the improvement of mass transfer of liquid and gas.Catalyst used in this paper is MnO2.The carrier of catalyst is the mixture of active carbon and black carbon. The results show that optimal content of black carbon is 20%. The adding of black carbon can greatly improve the performance of air electrode. The optimal PTFE content in air electrode after heat treatment is 30%. When thickness of catalytic layer is 0.20mm, the electrode has the best working performance and life. The distribution of granularity has influence to performance of electrode in a certain extent. On the condition that average particle size of active carbon is the same, the wider the size distribution is, the better the electrochemical property is. The electrodes will have better permeability and longer work life, when the optimal PTFE content in waterproof layer is 60%, thickness of waterproof layer is at about 0.8mm and the pore former is ethanol.The technique of electrode molding is cold press. It's shown in the results that the pressure has direct influence on the performance of air electrode. When the synthesising pressure of electrode is 20MP, the waterproof layer and catalytic layer can joint together well. Through heat treatment PTFE in waterproof layer and catalytic layer felt together. This avoids the flaking offand bubbly phenomena of air electrode and evidently improves the electrode performance and life.Air electrode of this research is applied to oxygen-producing unit. The bubbly phenomena have completely eliminated. The oxygen-producing unit can be running steadily for more than 1000 hours. And oxygen-producing apparatus has been putting into production.Through the research on electrolytic mechanism of electrochemical oxygen-producing unit made of air electrodes, it's revealed that changing catalyst content can adjust the proportion of different reaction processes. Two electron process is unfavorable to metal-air battery. But it's favorable to electrochemical oxygen producing unit.