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Aerogel and xerogel synthesis of solid oxide fuel cell materials by an epoxide assisted sol-gel method: Investigating high surface area ceramics for cathode applications.

机译：通过环氧化物辅助的溶胶-凝胶法气凝胶和干凝胶合成固体氧化物燃料电池材料：研究用于阴极应用的高表面积陶瓷。

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摘要

In this work, an epoxide initiated sol-gel method was developed for the aerogel and xerogel synthesis of YSZ and LSM and the application of aerogel derived YSZ to SOFC cathodes was investigated. A brief review of SOFC cathodes and a background to sol-gel chemistry and the epoxide addition method are presented in Chapter l.; Chapters 2 and 3 describe the synthesis of YSZ-precursor aerogels and xerogels by the epoxide method. The effects of epoxide, solvent, and drying method were examined. Aerogels calcined to 550 °C, consisted of homogeneous, nanoparticles (∼10 nm) with spherical morphologies and high surface areas (125 to 150 m2/g), whereas xerogel processing produced coarse, highly agglomerated powders. YSZ sol-gel materials, from 3 to 25 mol% Y 2O3, were successfully prepared with either propylene oxide or trimethylene oxide in both aqueous and mixed ethanol-water solutions of Zr4+ and Y3+ chlorides. Elemental analysis, XRD, and electron microscopy indicated that Y2O3 and ZrO2 formed a homogeneous nanostructure over a wide range of Zr/Y ratios, corresponding from 3 to 25 MOM Y203.; Chapter 4 details the sol-gel synthesis of LSM by the epoxide route. Unlike the YSZ gels, aerogel and xerogel processing of the gels produced remarkably similar mesoporous materials. Ambient drying resulted in high surface area xerogels (200 m 2/g) with nanostructured networks interconnecting particulate regions. The morphology of the resultant xerogels were intermediated between the networked structure of pure La xerogels and the particulate precipitates formed by the divalent cations. Calcination of the dried gels resulted in the crystallization of single-phase LSM nanoparticles (∼100 nm) by 700 °C, subsequent to decomposition of intermediate hydroxide, chloride, and oxychloride compounds.; Chapter 5 covers conventional electrochemical cell design and fabrication including results from a study on chemical degradation related to the fabrication process. In Chapter 6, the effect of YSZ surface area on composite YSZ-LSM cathodes was studied with respect to electrode fabrication, microstructure, and electrochemical performance is reported. High surface area aerogel derived YSZ powders were compared with relatively low-surface-area commercial YSZ powders.
机译：在这项工作中，开发了一种环氧引发的溶胶-凝胶法，用于YSZ和LSM的气凝胶和干凝胶合成，并研究了气凝胶衍生的YSZ在SOFC阴极上的应用。第一章简要回顾了SOFC阴极，溶胶-凝胶化学的背景和环氧化物的添加方法。第2章和第3章描述了通过环氧方法合成YSZ前体气凝胶和干凝胶。检查了环氧树脂，溶剂和干燥方法的影响。煅烧至550°C的气凝胶由具有球形形态和高表面积（125至150 m2 / g）的均相纳米颗粒（〜10 nm）组成，而干法凝胶处理则产生了粗糙，高度团聚的粉末。用Zr4 +和Y3 +氯化物的水溶液和混合乙醇水溶液，用环氧丙烷或环氧丙烷成功地制备了3至25 mol％Y 2O3的YSZ溶胶-凝胶材料。元素分析，X射线衍射和电子显微镜检查表明，Y2O3和ZrO2在很宽的Zr / Y比范围内形成了均匀的纳米结构，对应于3到25个MOM Y203。第4章详细介绍了通过环氧途径溶胶-凝胶法合成LSM。与YSZ凝胶不同，凝胶的气凝胶和干凝胶加工产生了非常相似的中孔材料。环境干燥导致高表面积干凝胶（200 m 2 / g）具有相互连接颗粒区域的纳米结构网络。所得干凝胶的形态介于纯La干凝胶的网络结构与由二价阳离子形成的颗粒状沉淀之间。干燥凝胶的煅烧导致单相LSM纳米颗粒（约100 nm）在700°C结晶，然后分解出中间的氢氧化物，氯化物和氯氧化物化合物。第5章介绍了常规的电化学电池设计和制造，包括与制造工艺有关的化学降解研究的结果。在第6章中，研究了YSZ表面积对复合YSZ-LSM阴极的影响，涉及电极的制造，微观结构和电化学性能。将高表面积气凝胶衍生的YSZ粉末与相对低表面积的商业YSZ粉末进行了比较。

著录项

  • 作者

    Chervin, Christopher N.;

  • 作者单位

    University of California, Davis.;

  • 授予单位 University of California, Davis.;
  • 学科 Chemistry Inorganic.; Engineering Materials Science.; Energy.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 185 p.
  • 总页数 185
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无机化学;工程材料学;能源与动力工程;
  • 关键词

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