氧化釓添加氧化鈰纖維與錳酸鍶鑭粉體之製備與分析

Abstract

在本研究中，選擇了兩種固態氧化物燃料電池的內部元件及一種單電池進行其製備及分析。 首先，利用化學共沉法合成氧化釓添加氧化鈰(GDC)之纖維。由於其較高的導電性，異價離子添加的氧化鈰是取代目前常見的釔安定氧化鋯(YSZ)電解質的適當材料。合成的GDC纖維透過SEM、TEM、DTA/TG、XRD及ICP-AES等技術進行其化學，結晶動力學及微結構等性質的分析。結果顯示纖維之合成過程屬於零級反應。且所合成之析出物的微結構會因檸檬酸及氫氧化鈉濃度之添加量不同而有所影響。除了纖維之外，膠粒、柱狀及片狀之析出物亦可透過不同比例之檸檬酸及氫氧化鈉濃度產生。 其次，當做固態氧化物燃料電池的陰極材料錳酸鍶鑭(LSM)，透過兩種溶膠凝膠法合成而得。其一為Pechini法，其二則是以聚丙烯酸(PAA)做為高分子添加劑的溶膠凝膠法。除了上述的分析技術，所合成之粉末也以SEM-EDS之技術進行全定量分析以得知其化學成分之分布。同時，LSM粉體終於熱處理過程中所殘餘之碳含量則以碳硫分析儀進行分析，並以三點直流方式測定LSM與YSZ間之介面電阻。 最後，電解質支撐之固態氧化物燃料電池也於此研究中製備。透過網印技術，LSM陰極薄膜及氧化鎳/氧化鋯(NiO/YSZ)陽極薄膜成功的披覆於氧化鋯的電解質支撐上。此氧化鋯電解質之電性利用交流阻抗分析儀進行分析。最後也報導所製備的三層燃料電池之單電池微結構。

This study, two components in solid oxide fuel cell (SOFC) and one cell were fabricated and analyzed. First, fibrous Gd2O3 doped ceria (GDC), which is the alternative material for electrolyte, was synthesized by chemical co-precipitate method. The chemical, growth and microstructural properties of the GDC fibers were characterized by scanning and transmission electron microscopies (SEM and TEM), differential thermogravimetry (DTA/TG), X-ray diffraction (XRD), and inductive coupling plasma-atomic emission spectroscopy (ICP-AES) technologies. The results of fiber synthesis reaction showed zero-order kinetics. The morphologies were closely affected by the concentrations of additives, citric acid and sodium hydroxide. Three types of morphologies, including spherical colloids, fibers, stick-in-bundles, and flakes could be synthesized by control the ratio of citric acid and sodium hydroxide. Second, LSM powders were synthesized by Pechini method and a sol-gel process with PAA as chelating agent. Besides the analysis technologies mentioned above, the powders were also characterized by quantitative energy dispersive spectroscopy (EDS) to identify their compositional homogeneity. In addition, the residual carbon content in the LSM powders and their electrical resistance of the LSM/YSZ interface were also analyzed by carbon/sulfur analyzer and 3-terminal measurement, respectively. Finally, an electrolyte supported SOFC was fabricated by screen printing. The electrical conductivity of 8Y-YSZ electrolyte analyzed by AC impedance and the microstructure of the tri-layer single cell were prepared and characterized.