纳米复合Li2SO4质子传导膜H2S中温燃料电池

开发了一种制备纳米复合Li_2SO_4质子传导电解质和膜电极组装(MEA)的工艺.与传统的丝网涂布工艺不同,新的制备工艺是将阳极、阴极催化剂与纳米复合电解质同时一次压制成MEA.这就使得MEA的设计具有某些结构上的特点,由于膜厚减少和电极与电解质之间的接触良好,可以降低电解质与电极之间的欧姆电阻,提高其机械和导电性能,增加膜的质子传导性以及改善电池的性能.用电子扫描电镜(SEM)和电化学阻抗分析技术对电解质薄膜进行了表征,结果表明,纳米复合材料改善了MEA的总体性能.由于膜的致密性和不透气性,不会发生气体穿透过膜的现象.MEA在H_2S环境中很稳定.电池结构为H_2S,(MoS_2/NiS Ag 电解质量 淀粉) /Li_2SO_4 Al_2O_3/(NiO Ag 电解质量 淀粉),空气、MEA厚为0.8mm、电解质组成为65% Li_2SO_4 35% Al_2O_3的单电池在680℃时产生最大功率密度为130mW/cm~2,相应的电流密度为200mW/cm~2.

A H2S Intermediate-Temperature Fuel Cell with Nano-Composite Li2SO4 Proton-Conducting Membrane

A nano-composite Li2SO4 proton-conducting electrolyte and a new preparation procedure of membrane-electrode assembly (MEA) were developed for the electrochemical oxidation of H2S. Instead of the traditional screen-printing method, in the MEA, both the anode and cathode catalysts were simultaneously pressed to form the cell with nano-composite electrolyte. This allows the design to possess some advantageous configurations that can diminish the Ohmic resistance between the electrolyte and the electrodes, enhance the mechanical and electrical properties, and improve the performance of fuel cells due to the membrane thickness reduction and the good contact between the electrolyte and the electrodes. The electrolyte was then characterized by scanning electron microscope (SEM) and electrochemical impedance spectrum techniques. The results indicate that the nano-composite materials improve the electrolyte integrity, and that no cross-over of H2S through the improved electrolyte occurs due to its high density, good compactivity and gas-impermeability. Moreover, MEA is stable in H2S stream. For a single cell with the configuration of H2S, ( MoS2/NiS + Ag + electrolyte + starch)/ Li2SO4 +Al203/(NiO +Ag + electrolyte + starch) and air in a MEA thickness of 0.8 mm and a Li2SO4 to Al2O3 weight ratio of 65: 35, the maximum power density is about 130mW/cm2 and the corresponding current density is about 200 mA/cm2 at 680 ℃.