本研究主要探討以噴霧熱解法製備元素釤摻雜至二氧化鈰的固態電解質材料Ce0.8Sm0.2O1.9 (20SDC)，並比較不同的濃度均勻度與離子導電性質兩者之間的關係。由於元素釤摻雜二氧化鈰具有良好的離子導電性質，故為固態氧化物燃料電池重要的電解質材料，並由前人的各項研究發現，在不同製程中，如固態法、溶膠凝膠法、噴霧熱解法等，釤摻雜至二氧化鈰中卻具有不同的最佳摻雜濃度，這意味者在不同製程中元素釤在二氧化鈰中有不同的分散行為，而具有不同的導電性質。因此本研究將利用噴霧熱解法製備釤摻雜二氧化鈰系統，進而探討元素釤摻雜的分佈情形對二氧化鈰導電性質之影響。此外前驅物的不同特性也會影響元素成分在粉體中的分散性質，如前驅物的密度、溶解度與水解能等因素與成分的分散性質有著密不可分的關係，因此本研究將選用四種前驅物：硝酸鈰銨、硝酸釤、醋酸鈰與醋酸釤，並探討不同前驅物的特性組合與成分分佈之間的關係。其中前驅物的量測分析，透過熱重分析量測不同前驅物的熱裂解溫度以及抽氣過濾法量測不同前驅物之溶解度。在粉體的量測分析上，將利用X光繞射儀鑑定(X-ray diffraction analysis, XRD)粉體的結晶結構，以及掃描式電子顯微鏡(Scanning electron microscopy, SEM)觀察粉體形貌，最後以冷凍切片技術製備粉體的穿透式電子顯微鏡試樣，並利用X光微區分析，量測粉體中元素釤的分散均勻性質。在電解質塊材的量測分析上，同樣使用XRD觀察其結晶結構，以及透過金相研磨技術並利用SEM觀察塊材內的微結構緻密程度，最後以交流阻抗分析儀量測塊材之阻抗變化，並計算其離子導電度與濃度均勻性質進行比較。由實驗結果中發現，對於釤摻雜二氧化鈰系統的成分分佈，水解能的影響因素更大於溶解性質，此外更發現成分的均勻性質與離子導電度，越均勻的成分分佈將獲得更高的離子導電度。

關鍵字：固態氧化物燃料電池、電解質材料、噴霧熱解法、二氧化鈰、水解能、氧化釤。

Samarium-doped ceria is one of the potential candidates for the application of solid oxide fuel cells due to the high oxygen ionic conductivity. Various techniques (e.g., solid state, sol-gel, and spray pyrolysis) have been reported on samarium-doped ceria, however the optimum dosages of samarium are still not clear, it means that there are different distributions of samarium in ceria. In this work, particles of samarium-doped ceria were synthesized from various precursors (cerium acetate, ammonium cerium nitrate, samarium acetate and samarium nitrate) using spray pyrolysis, and focused on the correlations between dopant concentrations and corresponding conductivities. In addition, the precursor properties also effect the distributed behavior of samarium in ceria, such as solubility, density and hydration energy of precursor.

The characterizations were divided in three parts: the first part focused on precursor analysis. The decomposed temperatures of various precursors were measured by thermogravimeteric analysis; the second part was particle analysis, The X-ray diffractometer (XRD) was used to investigate the crystallographic structure. The morphologies and particle sizes were characterized by using scanning electron microscope (SEM), and the dopant distributions in single particle were determined using energy dispersive X-ray spectroscopy; the final part was bulk analysis. The crystallographic structures of bulks were investigated by XRD, and the microstructures were observed by SEM. In addition, the ionic conductivities were also measured by electrochemical impedance spectroscopy (EIS).

According to the results of this work, the hydration energy has significant influence on the distributions of samarium in single ceria particle. Furthermore, the homogeneity of samarium in ceria is one of the important factors on ionic conductivity. In summary, the better homogeneity results in, the higher ionic conductivity.

Keyword: Solid oxide fuel cell, electrolyte material, spray pyrolysis, cerium, hydration energy, samarium.

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