【作者】 李勇；

【导师】 邵刚勤；

【作者基本信息】 武汉理工大学 ， 材料学， 2006， 硕士

【摘要】 固体氧化物燃料电池（SOFC）是一个可以直接将燃料的化学能转换为电能的电化学装置,被誉为21世纪最具有发展潜力的能源之一,它的热效率高、燃料的适应性强,能很好地满足区域供电、供热的需要,具有重要的经济和社会意义。 目前,固体氧化物燃料电池的研究正向800℃以下的中低温方向发展,在这种工作条件下可以使用低成本的金属连接材料,还可以提高电池材料的长期稳定性,降低电池各组分材料之间的浸蚀作用;但是,温度的降低也会增大固体电解质的欧姆损失,使电极的极化作用增大。为减小工作温度下固体电解质隔膜的电阻和提高电极的催化活性,近年来的研究工作主要集中在以下两个方面:一是研制中温下具有高离子导电率的新固体电解质材料,比如La（Sr）Ga（Mg）O₃或CeO₂基的电解质材料;二是采用超薄的电解质膜以增大中低温下电池的输出功率密度。其中电解质的薄膜化研究近年来在国际上受到越来越广泛的重视。 本文在平板固体氧化物燃料电池的电极制备、单电池研制（包括高温无机密封）和电池性能测试分析方面进行了尝试,合成了与之相匹配的阴、阳极材料,并在此基础上组装出了电解质支撑平板式和阳极支撑平板式YSZ-Ni|YSZ|LSM固体氧化物燃料电池单电池,设计组装了电池的气氛控制系统和性能测试系统,以H₂为燃料、空气为氧化剂,在温度为700～1000℃范围内测试了电池性能。 用XRD研究了YSZ-NiO金属陶瓷粉末的相结构,制得的粉末中的ZrO₂均为四方相;这是因为反应中生成的少量Y₂O₃进入到ZrO₂的晶格间隙,起到了稳定ZrO₂的作用。LSM的XRD图与非化学计量氧化物LaMnO（3.15）的图谱非常接近。 用SEM观察了YSZ-NiO阳极和LSM阴极的断面形貌。结果表明,阳极和阴极的晶粒和孔隙分布均匀,均为多孔结构。阳极支撑式SOFC的阳极平均厚度约为1mm,电解质的平均厚度约为0.5mm,阴极的平均厚度约为0.15mm。电解质层相对较为致密。定点电子能谱分析结果表明,阳极—电解质—阴极三合一结构中各部分的元素分布正常,电解质层有效地阻挡了阳极和阴极中元素的扩散,阴极材料中掺杂的Sr与ZrO₂发生了反应,形成了不导电相SrZrO₃,这也是导致整个电池性能不高的主要原因之一。更多还原

【Abstract】 Solid oxide fuel cells（SOFC） are expected to become one of the most potential energy sources in 21 century. It is an electrochemical device that converts the energy of a chemical reaction directly into electrical energy. They have high heat efficiency, good fuel adaptiveness, can meet satisfactorily the needs of local supply of power and heat. They will play an important role in our society and economy.Recent SOFC development has been focused on lower temperature operation less than 800℃. Such operation enables us to use low-cost metallic interconnects, long-term cell materials stability, and decrease the materials corrosion for plant components. However, it also increases both the ohmic loss at the solid-state electrolyte and the polarization loss at both electrodes. To reduce the ohmic loss of the electrolyte and the polarization loss of electrodes, two approaches have been conducted in resent years. One is to apply new materials such as La（Sr）Ga（Mg）O₃ or CeO₂ based oxides for electrolytes, which have higher conductivity than that of YSZ at lower temperature, and another is to use a thin film of Y₂O₃ stabilized ZrO₂ （YSZ） to increase the power density at low temperature, this approach is play an important role in the world wide efforts in the field of SOFC.Some works of the preparation of Solid oxide fuel cells such as electrode making, single cell preparation, performance examinations and high-temperature inorganic sealing were attempted in this work. The anode and cathode materials were synthesized and, on this base, a single electrolyte-support and a anode-support planar solid oxide fuel cell with YSZ-Ni |YSZ| LSM configuration were developed, the test system and the fuel control system was fabricated, its electrical performance were examined for operation with H2 as the fuel and the air as the oxidant over a temperature range of 700 to 1000℃.The crystal phases were investigated by X-ray diffraction （XRD）. The results showed that the YSZ-NiO powders contained mainly tetragonal ZrO₂. This is because the Y₂O₃ had entered into the clearance of ZrO₂ crystal lattice to stabilize the ZrO₂. The XRD pattern of LSM is very closed to the XRD pattern of nonstoichiometric oxide LaMnO₃.15.The fractured surface morphology of the YSZ-NiO anode, LSM cathode andpositive-electrolyte- negative （PEN） was observed by a scanning electron microscope （SEM）. The results showed that the grain sizes of anode and cathode ware a homogeneous microstructure and uniform distribution with porous configuration. About the anode-support SOFC, the average thickness of anode layer, electrolyte layer and cathode layer ware lmm, 0.5mm and 0.15mm. The electrolyte was compact. The element of positive-electrolyte-negative plate （PEN） ware analyzed by fixed-point EDS, the results showed that the infiltration of element in anode and cathode ware impeded by electrolyte. The Sr reacted with ZrCh in electrolyte to become SrZrC>3, which is not conductivity. This is one of the reasons of the bad SOFC’s performance.The open-circuit voltage （OCV） of electrolyte-support SOFC was over 1.01 V, the maximum power density at 1000°C reached to 7.73mW/cm2. It was found that the large ohmic losses of the electrolyte was the main factor responsible for the relative low output power density. The relationship between the OCV and operating temperature or the fuel flow rates was also investigated. The results showed that the open-circuit voltage （OCV） of anode-support SOFC was over 0.98 V, the maximum power density at 900°C reached to 3.31mW/cm2.更多还原