【作者】 沈旭；

【导师】 赵康；

【作者基本信息】 西安理工大学 ， 材料科学与工程， 2008， 硕士

【摘要】 固体氧化物燃料电池（SOFC）是一种将燃料的化学能直接转变成电能的发电装置,以其具有能量转换效率高、无污染、燃料范围广等优点而倍受关注。目前,SOFC的研究正向800℃以下的中低温方向发展,实现其中低温化的主要途径有:电解质的薄膜化、新型高电导率电解质材料的研究以及SOFC新型结构的研究。在SOFC新型结构的研究中,蜂窝结构被认为具有较好的发展前景。蜂窝式SOFC具有比表面积大,体积功率密度高;不用高温密封和连接,结构牢固;不用支撑元件,体积小,质量轻;电池组组装简便等优点,可促进SOFC向中低温化发展。本文主要探讨了流延法制备SOFC蜂窝体的工艺,主要包括以下方面:采用流延法制备高致密度的YSZ基片,分析了影响浆料粘度的因素,对流延过程中的工艺参数和流延膜干燥过程进行了研究,并确定了YSZ基片的排胶烧结工艺。结果表明:当流延浆料YSZ含量为45wt.%,球磨48h,所得浆料粘度适合流延;流延速度控制在0.6cm/s,干燥温度25℃,溶剂气氛中干燥,可以获得高密度、表面平整光滑的生片;排胶后以1℃/min速率升温至1350℃,保温3h后得到的YSZ基片的相对密度可达95.2%。以淀粉为造孔剂,采用流延法制备多孔电极。XRD分析表明:阳极Ni-YSZ在1250℃、1300℃、1350℃下真空烧结3h后物相组成均为Ni、YSZ和少量NiO;阴极LSM-YSZ在1250和1300℃下真空烧结3h后物相组成为LSM和YSZ,在1350℃烧结3h后,则出现了少量的La₂Zr₂O₇。随着淀粉添加量的增加,阳极和阴极的径向收缩率和孔隙率都随之增加。SEM分析表明,阳极和阴极的孔隙分布均匀,孔径范围约为1～10μm。在流延法制备YSZ基片和多孔电极的研究基础上,通过卷压、堆垛、热合工艺将流延法制备的二维片状薄片转化为三维立体结构,制备SOFC蜂窝体。研究了蜂窝体的热合和烧结工艺,并对蜂窝体进行了微观形貌、电子能谱和抗热震性能测试分析。结果表明:由该方法制备的SOFC蜂窝体具有规则的形状,通孔率高;电极与电解质的界面结合良好;阳极和阴极元素在孔壁内发生了扩散;蜂窝体具有较好的抗热震性能。更多还原

【Abstract】 Solid oxide fuel cell（SOFC）is an energy conversion device that produces electricity directly from fuels by electrochemical reactions.Being several advantages,such as higher energy conversion efficiency,no pollution and good fuel adaptiveness,SOFC has been received considerable interests worldwide.Recent SOFC development has been focused on lower temperature operation less than 800℃.There are three approaches for lower temperature operation:applying new materials which have high conductivity,using a thin film of electrolyte as well as applying new SOFC structure.In the new SOFC structure’s research,the honeycomb is considered to be advanced.The honeycomb SOFC have a lot merits,such as high specific area and power density,no need of elevated temperature sealing and supporting element,small volume and weight.In this dissertation,the fabrication processes of SOFC’s honeycomb body have been exhaustively studied.Detailed work is as following:The compact YSZ slice has been prepared by Tape casting.The factors which influence the viscosity of slurry have been studied.The technical parameters and the drying process in the tape-casting process have been studied respectively.The batching curve has been made according to the TG analysis of green tape.The results show that the slurry is suitable to tape casting when the YSZ content is 45wt.%,milled 48 hours;the smooth green tape with high density can be gained by limiting the tape velocity at 0.6mm/s and the temperature at 25℃when drying in the solvent atmosphere.The relative density of YSZ slice sintered at 1350℃for 3h with heating rate of 1℃/min is 95.2%.The porous electrode has been prepared by tape casting with the addition of amylum as poreformers.The XRD analysis show that the main phase of Ni-YSZ sintered at 1250℃,1300℃,1350℃for 3h are YSZ,Ni and NiO.The main phases of LSM-YSZ sintered at 1250℃ and 1300℃are LSM and YSZ,but the main phases sintered at 1350℃are LSM,YSZ and few La₂Zr₂O₇.The shrinkage and porosity of electrode are increased with increasing the amylum content.The pores of the electrode are distributed homogeneous and the aperture’s scope is 1～10μm.The SOFC’s honeycomb body has been prepared by winding,stacking and heat sealing the two dimensional slices prepared by tape casting.The heat sealing process and sintering curve have been investigated.The micro pattern,EDS,thermal shock resistance and compressive strength have been tested and analyzed.The results show that the SOFC’s honeycomb body prepared by this method has regular shape,the ratio of open pores is high.The combination of the electrode and electrolyte is good.The elements of anode and cathode are diffused in the wall of hole.The honeycomb body has good thermal shock resistance.更多还原