固体氧化物燃料电池一些关键材料的性能研究

发布时间：2018-01-06 10:23

本文关键词：固体氧化物燃料电池一些关键材料的性能研究　出处：《华南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：固体氧化物燃料电池(SOFC)是一种高效地将燃料的化学能直接转换成电能的新型发电装置，被认为是有史以来用途最为广泛的能源解决方案。世界上越来越多的研究者也在关注SOFC的应用和发展，然而电池的性能与材料有着密不可分的关系，因此研究选择合适的电极和电解质材料是制备出高性能电池的重要保证。本论文围绕这个主题展开，首先系统地研究了不同的合成方法对阴极材料LSM的影响，然后采用高温固相法合成高电导率的电解质材料LSGM，并将其运用于直接碳固体氧化物燃料电池(DC-SOFC)，研究其电化学性能。阴极材料的性能与粉体的形貌、粒径大小及分布和烧结性等有关。选择合适的制备方法是制备高输出性能电池的重要保证。首先分别采用固相法、甘氨酸-硝酸盐燃烧法和溶胶-凝胶法制备了SOFC阴极材料La0.8Sr0.2MnO3(LSM)。将合成的粉体分别在不同的温度下烧结，并通过XRD确定合成粉体成相最低烧结温度均是900C；利用扫描电镜对合成的粉体进行微观结构的观察和分析，结果表明，燃烧法和溶胶-凝胶法制备的LSM粉体都满足阴极材料疏松多孔的要求；并采用Van-der Pauw四端法测量片状阴极的直流电阻进而计算电导率，结果表明三种方法合成的阴极的电导率(100S/cm)均满足SOFC阴极材料电导率的要求；采用三电极法研究LSM阴极材料的活化行为，表明溶胶-凝胶法制备的LSM阴极与电解质YSZ的界面阻抗均是最小。同时，将3种方法制备的LSM应用到多孔阳极支撑型的SOFC上，制备成单电池，并采用四端法对单电池的输出性能进行测试，溶胶-凝胶法合成的LSM阴极制备的单电池在800C时输出功率密度最大（317mW/cm2）。总的来说，溶胶-凝胶法合成的LSM粉末能够有效满足SOFC阴极材料的要求。 SOFC中最常用的电解质材料是YSZ，但是在低温时(1000C)，YSZ电导率不是很高，从而增大了欧姆电阻，电池的输出性能受到影响。而LSGM电解质在中低温下电导率较高，被认为是一种很有潜力的中低温电解质材料。本论文采用固相法合成了LSGM，并采用XRD和SEM对其进行表征；然后采用浸渍法成功制备出管状LSGM支撑体，并采用担载5wt%Fe催化剂的活性炭为燃料测试其性能：850C时，LSGM支撑的DC-SOFC的最大输出功率密度为383mW·cm-2，是YSZ支撑的最大功率密度(297mW·cm-2)的1.2倍，同时，从欧姆阻抗谱图上可以看出来，，在测试温度范围内，LSGM支撑的DC-SOFC的欧姆电阻比YSZ支撑的欧姆电阻均要小，YSZ支撑的DC-SOFC在850C时欧姆电阻为0.80Ω·cm2，而LSGM支撑的DC-SOFC在850C时欧姆电阻为0.52Ω·cm2，相对与YSZ支撑的DC-SOFC降低了35%。结果表明，采用电导率更高的电解质材料能够有效地提高电池的输出性能。电池稳定性测试表明，电池的性能随着时间逐渐衰减，较少的碳燃料会导致电池运行时间的缩短和碳利用率的降低。
[Abstract]:Solid oxide fuel cell (SOFC) is a kind of efficient fuel chemical energy directly into electricity new energy generating device, is regarded as the most widely used energy solutions. More and more researchers in the world are also concerned about the application and development of SOFC, but the performance and battery materials there is a close relationship, so the choice of electrode and electrolyte materials appropriate is prepared an important guarantee for high performance battery.
This paper focuses on this theme, the first systematic study of the influence of different synthesis methods of cathode material LSM, and then by high temperature solid electrolyte materials with high conductivity LSGM synthesis method, and it is used to direct carbon solid oxide fuel cell (DC-SOFC), the research on the electrochemical performance.
The morphology and properties of powder cathode materials, particle size and distribution and sintering and so on. Choose the appropriate preparation method is an important guarantee for the preparation of high performance battery output. First of all, using solid phase method, SOFC cathode material La0.8Sr0.2MnO3 was prepared by sol-gel method and glycine nitrate combustion (LSM) the powders were sintered at different temperatures, and determined by XRD powder synthesis is the lowest sintering temperature is 900C; observation and Analysis on the microstructure of the powder synthesized by using scanning electron microscopy. The results show that the combustion of LSM powders prepared by sol gel method and can meet the requirements of osteoporosis the porous cathode material; and the DC resistance Van-der Pauw measurement sheet four terminal method and cathode conductivity calculation, the results show that the conductivity of the cathode prepared by three methods (100S/cm) can meet the conductance of SOFC cathode materials The rate of demand; the activation behavior of three electrode cathode materials of LSM, showed that the interface impedance of sol gel LSM cathode and YSZ electrolyte is minimal. At the same time, the 3 kinds of preparation method of LSM is applied to the porous anode supported SOFC, prepared into a single cell, and by four the output end method of the performance of the single cell test, sol-gel synthesis of LSM cathode preparation of single cell in 800C when the output power density maximum (317mW/cm2). In general, LSM powders were synthesized by sol-gel method can effectively meet the requirements. SOFC cathode materials
The most commonly used electrolyte material in SOFC is YSZ, but at low temperature (1000C), the conductivity of YSZ is not very high, thereby increasing the ohmic resistance, the output performance of the cell is affected. And LSGM electrolyte at low temperature and high conductivity, is considered to be a potential low temperature electrolyte materials. In this thesis, LSGM was synthesized by solid state method, and was characterized by XRD and SEM; and then by the impregnation method successfully prepared LSGM tubular supporting body, and using activated carbon supported 5wt%Fe catalyst for testing the performance of fuel: 850C, LSGM support DC-SOFC maximum output power density of 383mW - cm-2, is the largest power the density of YSZ support (297mW - cm-2) 1.2 times, at the same time, the figure can be seen from the impedance spectrum in the measuring temperature range, ohmic resistance of the ohmic resistance of LSGM supported DC-SOFC were smaller than YSZ support, YSZ support DC-SOF When 850C C ohm resistor of 0.80 - cm2, LSGM and DC-SOFC support at 850C ohm resistor of 0.52 cm2, compared with YSZ supported DC-SOFC reduced 35%. results show that the higher the conductivity of electrolyte materials can effectively improve the output performance of the battery. The battery stability test shows that the performance of the battery with time gradually decay, less carbon fuel will lead to lower utilization of the battery running time shortened and carbon.

【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM911.4

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