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在提高大电流密度下工作时空气电极的寿命。以活性炭、乙炔黑、PTFE乳液为原料,用辊压法制备空气电极,并将其置于惰性气氛(N2,CO2)中烧结。用TG-DTA研究电极材料的热行为,用扫描电子显微镜(SEM)、压汞分析、透气性测试等方法表征空气电极的孔结构,用稳态极化曲线法测定电极的电化学性能。研究了烧结影响空气电极的微孔结构及其稳定性的机理。试验结果表明,烧结工艺能极大地提高空气电极的寿命和性能,这可归因于烧结使PTFE与电极材料中的炭粒子凝结为一体,保持了三相界面的稳定,烧结过程中PTFE中的表面活性剂和低分子量的聚合物分解,起到造孔的作用,增加了电极的三相反应表面积。试验结果有助于优化电极的制备工艺。
The life of the air electrode when working at high current densities. Using activated carbon, acetylene black and PTFE emulsion as raw materials, the air electrode is prepared by the rolling method and sintered in an inert atmosphere (N2, CO2). The thermal behavior of the electrode material was studied by TG-DTA. The pore structure of the air electrode was characterized by scanning electron microscopy (SEM), mercury intrusion porosimetry and air permeability test. The electrochemical performance of the electrode was determined by steady state polarization curve. The mechanism of sintering affecting the micropore structure of air electrode and its stability was studied. The experimental results show that the sintering process can greatly improve the life and performance of the air electrode, which can be attributed to the sintering of PTFE and carbon particles in the electrode material as a single entity to maintain the stability of the three-phase interface, PTFE in the sintering process Surfactants and low molecular weight polymers decompose to create pores and increase the three-phase reaction surface area of the electrode. The test results help to optimize the electrode preparation process.