固態電解質為高氧離子導電率的導體，利用晶粒本身性質，藉由晶粒中氧空缺來傳導氧離子，螢石結構(Fluorite Structure)為具有高氧離子導電率的結晶構造，純的CeO2從室溫至熔點皆為穩定的螢石結構，不需進行穩定化，摻雜異價陽離子，以增加氧空缺，提高氧離子導電率，具有比現行商業化的氧化釔安定化氧化鋯(YSZ)固態電解質還要高的離子導電率以及較低的活化能，極有希望成為固態氧化物燃料電池(Solid Oxide Fuel Cell,SOFC)的電解質材料。
本研究以化學共沉法製備Ce1-xSmxO2-x/2奈米級粉末，經過加壓成型、燒結後作為固態電解質，利用XRD、SEM、BET，針對不同添加比例，分析粉末及燒結體的結晶相、顯微結構、緻密度，以及使用直流電法(DC-method)量測其導電率。
以Sm3+摻雜CeO2固態電解質，可有效提高氧離子導電率，且隨著添加量的增加，氧空缺濃度增加，導電率也增加，在800℃時導電率由2.41×10-4S/cm (CeO2) 提高到2.3×10-2S/cm(Ce0.8Sm0.2O1.9)，但當添加比例超過x=0.2時，導電率並沒有跟著增加，其原因是因為氧離子空位的有序化，缺陷締合以及靜電相互作用所造成的。活化能隨著添加比例增加而降低，在x=0.2活化能為0.892(eV)，繼續增加會使活化能升高，可與導電率結果作對照。

The Solid electrolyte is a conductor of the high oxygen ionic conductivity. It uses the nature from crystalline grain itself, as well as the oxygen vacancy inside to conduct oxygen ions. Fluorite Structure is a crystal conformation with high oxygen ionic conductivity. The pure CeO2 is stable Fluorite Structure both under the room temperature and melting point, so it is not necessary to stabilize and add unsual valence cation to increase the oxygen vacancy and increase oxygen ion electric conductivity. Besides, as compared to the current commercial YSZ (Yttria Stabilized Zirconia) solid electrolyte, it has higher ionic conductivity and lower active energy; therefore, it’s very possible that doped CeO2 could become the electrolyte material of solid oxide Fuel Cell (SOFC).

In this research, firstly, we adopted the method of “Chemical Coprecipitation” to produce SmxCel-xO2-x/2 powder. Secondly, after pressurizing to form its shape, and sintering, it would become solid electrolyte. Then, we used XRD, SEM, BET, in accordance with different adding proportion, and analyzed powder, the crystal phase of sintered substances, microstructure, and fineness In addition, we also used DC-method to measure its ionic conductivity.

By adding Sm3+ to CeO2 solid electrolytes could effectively increase the oxygen ion electric conductivity. With the increase of adding amount, the concentration of oxygen vacancy would increase, as well as the ionic conductivity. When the temperature reaches 800℃, the electric conductivity can increase from 2.41×10-4S/cm (CeO2) to 2.3×10-2S/cm(Ce0.8Sm0.2O1.9). However, if the adding proportion exceeds x=0.2, the ionic conductivity will not increase. The reason is because the vacancy of oxygen ion is formed by functioning between ordering, flaw association, and static electricity. The activation energy would be reduced by the increase of adding proportion. When x=0.2, the active energy will be 0.892(eV), and if keeping increasing, the active energy would also increase. The result can be a comparison of the result of electric conductivity.

1.黃鎮江, “燃料電池”, 全華科技圖書股份有限公司 (2003)
2.Minh N. Q. and Takahashi T., “Science and Technology of Ceramic Fuel Cells”, Elsevier Science B. V. (1995)
3.Appleby A. J. and Foulkes F. R., “Fuel cell hand book”, Van Nostrand Reinhold (1989)
4.Gregor H., “Fuel cell technology hand book”, CRC Press (2002)
5.Geller S., “Solid Electrolytes”, Springer-Verlag (1977)
6.Hagenmuller P. and Cool W. V., “Solid electrolytes general principles, characterization, materials, applications”, Academic Press (1978)
7.Inaba H. and Tagawa H., “Ceria-based solid electrolytes”, Solid State Ionics, 83, 1~16. (1996)
8.Yahiro H., and Koichi E.,“Electrial properties and mircostructure in the system ceria-alkaline earth oxide”, Journal of Materials Science, 23, 1036~1041. (1988)
9.Blomgren G. E.；Eveready Battery Co. , “Positive Electrode Materials for Nonaqueous Secondary Batteries” Role of Ceramics in Advanced Electrochemical Systems , 103~112 , The American Ceramic Society (1996)
10.Huang W. , Shuk P., “Properties of sol-gel prepared Ce1-xSmxO2-x/2 solid electrolytes”, Solid State Ionics, 100, 23~27. (1997)
11.Chang-Jean J. Y., Su W. S. and Huang M. H., “Sintering of 3mol％ Yttria-doped Zirconia Powders Prepared by Water or 1-Octanol Extraction Variant of Sol-gel Process”, Journal of Materials Science and Engineering, Vol. 32, No 4, pp. 179~185. (2000)
12.Yunfeng G. and Gang L., “Sintering and electrical properties of coprecipitation prepared Ce0.8Y0.2O1.9 ceramics”,Materials Research Bulletin 35 297~304. (2000)
13.Dabing L., Jiandong H. and Jianshe L., “Synthesis of nanometer (CeO2)0.9-x(GdO1.5)x(Sm2O3)0.1 powders by sol-gel low temperature combustion”, Journal of the Chinese Ceramic Society, 29, 340~343. (2001)
14.Shaowu Z, Qingxi F, Yin L., et al.“Novel azeotropic distillation process for synthesizing nanoscale powders of yttria doped ceria electrolyte.”，Materials Letters, 47 ,351~355. (2001)
15.G.uo-Bin J. and Ming-Hsien H., “Preparation of samaria-doped ceria for solid-oxide fuel cell electrolyte by a modified sol-gel method”, Journal of Materials Science, J. Am. Ceram. Soc,36 5839-5844 (2001)
16.Ranran P, Changrong X, “Sintering and electrical properties of (CeO2)0.8(Sm2O3)0.2 powders prepared by glycine-nitrate process” Materials Letters 56 1043~1047. (2002)
17.張晏韶, “以微波加熱燃燒合成法製備異質摻雜CeO2固溶體粉末應用於固態氧化物燃料電池中固態電解質之研究”成功大學碩士論文(2004)
18.黃鼎翰, “以低溫水熱法合成奈米級釤及鉍摻雜鈰系固態氧化物燃 料電池電解質與其電化學性質之研究” 台灣科技大學碩士論文(2004)
19.黃銘賢, “以Doped CeO2為固態電解質的陶瓷燃料電池”, 國科會研究計畫報告 (2001)
20.Sammes N. M., Tompsett G. A., Näfe H. and Aldinget F., “Bismuth based oxide electrolytes structure and ionic conductivity”, Journal of the European Ceramic Society, 19, 1801~1826. (1999)
21.Kai J. and Cheng P., “Sol-Gel synthesis and porperties of GdxCe1-xO2-x/2 solid solutions”, Chemical Journal of Chinese Universities, 22, 1279~1282. (2001)
22.Kai J. and Xiuying Z., “Solid electrolytes used for SOFC”, Chinese Journal of Rare Metals, 25, 121~125. (2001)
23.Cook R. L., “Perovskite solid electrolytes for intermediate temperature solid oxide fuel cells”, Journal of the Electrochemistry Society, 137, 3309~3310. (1990)
24.汪建民主編, “陶瓷技術手冊(上)、(下)”, 中華民國粉末冶金協會, 台北市(1999)
25.Mccolm I. J. and Clark N. J., “Forming, Shaping and Working of High-performance Ceramics”, published by Chapman and Hall, New York.(1989)
26.Rumpf H. and Schubert H., in “Ceramic Processing before Firing”edited by G. Y. Onoda, and L. L. Hench, published by John Wiley & Sons, 357(1978)
27.M. S. Kaliszewski and A. H. Heuer, J. Am. Ceram. Soc, 75 ,1504~1509. (1990)
28.Taruta S., Kitajima K., Takusagawa N., Okada K. and Otsuka N., “Influence of Coarse Particle Size on Packing and Sintering Behavior of Bimodal Size Distributed Alumina Powder Mixtures”, Journal of the Ceramic Society of Japan, 101 [5], 583~588. (1992)
29.Smith J. P. and Messing G. L., “Sintering of Bimodally Distributed Alumina Powders”, J. Am. Ceram. Soc., 67 [4], 238~242. (1984)
30.Kimura T., Matsuda Y., Oda M. and Yamaguchi T., “Effects of Agglomerates on the Sintering of Alpha-Al2O3”, Ceram. International, 13, 27~34. (1987)
31.陳家榮, “Advanced Ceramic Powders and Nano Ceramic Powders”， 第一屆海峽兩岸粉體製備科學與技術研討會 (2003)
32.Paul Bowen and Claude Carry, “From powders to sintered pieces: forming, transformations and sintering of nanostructured ceramic oxides”, Powder Technology, V 128, No. 2-3, 248~255. (2002)
33.Ashby M. F., “A First Report on Sintering Diagrams”, Acta Metal., 22, 275~289. (1974)
34.孫千媖, “鹼金屬離子對薄膜電池氧化物電解質缺陷結構之影響”, 碩士論文 (2001)
35.Balazs G. B. and Glass R. S., “AC-Impedance Studies Rare-Earth-Oxides and Their Application to Solid Oxide Fuel-Cells”, Solid State Ionics, 52, 165 (1995)
36.Christie G. M., Van Berkel F. P. F, “Microstructure-ionic conductivity relationships in ceria-gadolinia electrolytes”, Solid State Ionics, 83, 17~27. (1996)
37.Hideaki I. , “Sintering behaviors of ceria and Gadolinia-doped ceria”, Solid State Ionics, 106, 263~268. (1998)
38.劉旭俐、馬峻峰,“固體氧化物燃料電池材料的研究進展”,硅酸鹽通報,1,24~29. (2001)
39.任引哲,“稀土複合氧化物的電導及在SOFC中的應用”,化學研究，12,59~64 (2001)
40.Dixon J. M. and Lagrange L. D., “Electrical resistivity of stabilized zirconia of elevated temperatures”, Journal of the Electrochemistry Society, 110, 276~280. (1963)
41.Strickler D. W. and Carlson W. G., “Ionic conductivity of cubic solid solutions in the system CaO-Y2O3-ZrO2”, Journal of the American Ceramic Society, 47, 122~127. (1964)