目前固態氧化物燃料電池(SOFC)在中溫(600℃-800℃)運作時，在電解質與陰極界面易產生較大極化電阻，降低其工作效率；近年來以具離子導性的陰極材料或導電氧化物與電解質混合之複合電極來取代傳統陰極材料(低離子導性)，以氧離子導性較高的電極當做陰極可以增加氧氣反應面積並降低極化電阻。
本實驗以常見之SOFC陰極材料：鈣鈦礦結構 (perovskite)之導電氧化物(La0.75Sr0.25CuO2.5(LSCu)， La0.8Sr0.2MnO3(LSM)及Y0.5Sr0.5MnO3(YSM))與高導電率之鉍系氧化物離子導體搭配，形成複合電極，降低其電解質與電極之阻抗，增加SOFC之效率。
((Bi2O3)0.73(SrO)0.27)0.85(Nb2O5)0.15為立方相氟化鈣結構及正交相SrBi2Nb2O9共存，利用元素分析找出單相之氟化鈣型立方相氧化鉍，其組成為-(Bi0.887Sr0.06Nb0.053)2O3.046 (SNB)，具有良好的導電率及熱穩定性，在450℃時，其導電率之數值為2.42×10-2 S/cm，比單一離子添加系統中的鉺安定氧化鉍或釔安定氧化鉍高，根據SNB導電性較高之特性，SNB與鈣鈦礦型氧化物合成之複合電極具有較大的潛力。
在perovskite-SNB混合粉末中就高溫反應性而言其大小為：LSCu-SNB > LSM-SNB > YSM-SNB，LSCu與SNB在熱處理溫度700℃以上會反應生成菱方相之鉍系氧化物(La0.3Bi0.7O1.5)及化合物Bi2Sr2CuO6，LSCu本身會相分解成La2CuO4及CuO，原SNB之立方相已完全消失；在LSM-SNB系統中，LSM會與SNB形成菱方相之鉍系氧化物；在YSM-SNB系統中經800oC熱處理20小時後並未有第二相產生，但是發現YSM之峰值強度下降可能發生有原子擴散的行為。
為了確認擴散元素，進一步分析其擴散偶，在LSCu-SNB系統中發現La-Bi氧化物反應層及Bi-Cu氧化物反應層，推論Bi-Cu氧化物為一介穩相，經長時間熱處理後可能會變成Bi2Sr2CuO6；在LSM-SNB中反應區域以非層狀的方式呈現，在LSM側具有富Bi離子之區域，此區域為La離子固溶之SNB菱方相；在YSM-SNB系統中，發現Sr-Bi 氧化物及YMnO3之存在，推論為Sr與Bi離子反應而造成的現象。LSCu-SNB、LSM-SNB及YSM-SNB三系統在SNB側發現SrBi2Nb2O9第二相，其生成原因可能為Bi離子的擴散，導致原SNB側中的Sr及Nb離子濃度上升，超過SNB之立方相氟化結構之固溶限而析出第二相。
以perovskite-SNB之複合電極與SNB電解質製成perovskite- SNB/SNB/Pt之半電池，測試複合電極與SNB電解質之間的過電壓。在LSCu-SNB、LSM-SNB及YSM-SNB系統中，YSM-SNB複合電極與SNB電解質之過電壓值在450℃下測試為具有最低的過電壓，其極化程度最低，對SNB電解質而言，YSM-SNB系統為較可行之複合電極。

When Solid oxide fuel cell working durance 600℃-800℃, interface resistance raise between electrolyte and electrode result as decreasing efficiency of SOFC. High ionic conductivity electrode or composite electrode consisting of electrolyte and electrode replace traditional electrode (poor ionic electrode)result as raise reaction area of oxygen and reducing interface resistance.
In this research, using composite electrode consisting of perovskite type conducting oxide (La0.75Sr0.25CuO2.5 (LSCu), La0.8Sr0.2MnO3 (LSM) and Y0.5Sr0.5MnO3 (YSM)) and Bi2O3 based electrolyte as cathode of SOFC. The composite electrode decreased interfacial resistance and raise efficiency of SOFC.
By doping Nb2O5 into (Bi2O3)0.73(SrO)0.27 rhombohedral structures, the rhombohedral structures were able to stabilize to cubic structures which have high conductive property. ((Bi2O3)0.73(SrO)0.27)0.85(Nb2O5)0.15 were δ phase and SrBi2Nb2O9 coexisted. The composition of the δ phase was analyzed by SEM/EDS analysis, and found to be (Bi0.887Sr0.06Nb0.053)2O3.046 (SNB). The single δ phase (Bi0.887Sr0.06Nb0.053)2O3.046 shows higher conductivity of 2.42*10-2S/cm at 450˚C.
In the perovskite-SNB mixed powder, the reactivity in the high temperature is: LSCu-SNB >LSM-SNB>YSM-SNB. LSCu reacted with SNB as La0.3Bi0.7O1.5 and Bi2Sr2CuO6 when annealing temperature upon 700℃. LSCu phase decomposed to La2CuO4 and CuO phase. In LSM-SNB system, LSM reacted with SNB to form rhombohedral phase. In YSM-SNB system, no extra phases appear in the XRD pattern after annealing at 800℃ for 20h. However, the peak intensity of YSM reduced due to diffusion of atoms.
In order to check diffused atom, analysis by diffusion couple. La-Bi oxide and Bi-Cu oxide reaction layer are observed in the LSCu-SNB. According to XRD pattern of LSCu-SNB mixed powder, Bi-Cu oxide reacted with Sr ions as Bi2Sr2CuO6 after annealing for a long time. In the LSM-SNB system, reaction zone was presented by non-layer in the LSM side. The dotted Bi rich zone spread in the LSM matrix. The Bi rich zone is rhombohedral phase La3+ doped bismuth oxide. In YSM-SNB system, Sr2+ reacted with Bi3+ as Sr-Bi oxide. Three systems were observed secondary phase (SrBi2Nb2O9) in the SNB side due to diffusion of Bi3+.
The over-potential of semi-cell (perovskite-SNB/SNB/Pt) was measured by current-interruption technique. YSM-SNB composite electrode and SNB electrolyte has the lowest over-potential among three systems. YSM-SNB composite electrode was more suitable for SNB electrolyte than LSCu-SNB and LSM-SNB.

1 T. Setoguchi, M. Sawano, K. Eguchi, and H. Arai, “Application Of The Stabilized Zirconia Thin-film Prepared By Spray Pyrolysis Methed To SOFC”, Solid State Ionics, 40-41, (1990) 502.

2 T. Takahashi, “H. Iwahara, High oxide ion conduction in sintered oxides of the system Bi2O3-Y2O3” Journal of Applied Electrochemistry, 5 187 (1975)

3 H. Iwahara, “ Formation of high oxide ion conductive phases in the sintered oxides of the system Bi2O3-Ln2O3 (Ln= La-Yd), ” Journal of solid state chemistry,39, 173-180.(1981)

4 A. Watanabe and T. Kikuchi, “cubic-hexagonal transformation of yttia-stabilized -bismuth sesquioxide, Bi2-2xY2xO3 (x=0.215-0.235),” Solid State Ionics, 21 287. (1986)

5 T. Takahashi, H. Iwahara and T. Esaka, “High oxide ion conduction in sintered oxide of the system Bi2O3-M2O5” Journal of the Electrochemistry Society, 124 1563.(1977)

6 V. J. Powers, Ph D. thesis, Ohio State University, (1989).

7 A. Watanabe, “Is it possible to stabilize -Bi2O3 by an oxide additive?,” Solid State Ionics, 40/41 89. (1990)

8 P. Conflant, J. C. Boivin, " Etude structure par diffractometrie X A haute temperature du conducteur anionique Bi0.844Ba0.156O1.422, " Solid State Ionics, 9&10, 925, (1983)

9 J. C. Boivin, D. J. Thomas, "Crystal chemistry and electrical properties of bismuth-based mixed oxides, " Solid State Ionics, 5, 523, (1981)

10 G. Meng, "Conductivity of Bi2O3-based oxide ion conductors with double stabilizers" Solid State Ionics, 28-30, 533, 1988

11 A. A. Yaremchenko, V. V. Kharton, E. N. Naumovich, A. A. Tonoyan and V. V. Samokhval, “Oxygen ionic transport in Bi2O3-based oxides: II. The Bi2O3-ZrO2-Y2O3 and Bi2O3-Nb2O5-Ho2O3 solid solutions”, J Solid State Electrochem., 2, 308-314, 1998.

12 M. Benkaddour, M. C. Steil, M. Drache and P. Conflant, “The influence of the particle size on sintering and conductivity of Bi0.85Pr0.105V0.045O1.545 ceramics”, J. Solid State Chem., 155, 273-279, 2000.

13 M. G. Lazarraga, F. Pico, J. M. Amarilla, R. M. Rojas and J. M. Rojo, “The cubic Bi1.76U0.12La0.12O3.18 mixed oxide: Synthesis, structure characterization, thermal stability and electrical properties”, Solid State Ionics, 176, 2313-2318, 2005.

14 H. C. Yu and K. Z. Fung,”Role of Sr Addition on the Structure Stability and Electrical Conductivity of Sr-Doped Lanthanum Copper Oxide Perovskites”, J. Mater. Res.,19, 943. (2004)

15 H. C. Yu and K. Z. Fung, "Electrode Properties of La1-xSrxCuO2.5-δ as New Cathode Materials for Intermediate Temperature SOFCs" J. Power Sources, 133, 162. (2004)

16 H. C. Yu and K. Z. Fung “Reaction Between Strontium-Doped Lanthanum Cuprate and Yittria-Stabilized Zirconia ” J. Am. Ceram. Soc., 89 [9] 2881–2886 (2006)

17 X. Ding, C. Cui, L. Guo “Thermal expansion and electrochemical performance of La0.7Sr0.3CuO3-δ-Sm0.2Ce0.8O2-δ composite cathode for IT-SOFCs” Journal of Alloys and Compounds, 481, 845–850 (2009)

18 J. Li, Q. Huang, Z. W. Li, L. P. You, S.Y. Xu and C. K. Ong,” Enhanced magnetoresistance in Ag-doped granular La2/3Sr1/3MnO3 thin films prepared by dual-beam pulsed-laser deposition” J.Appl. Physi., 89(6), 7428-7430 (2001)

19 A. Chakraborty, P. S. Devi and H. S. Maiti, “PREPARATION OF La1-XSrXMnO3 (0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR- EQUAL-TO-0.6) POWDER BY AUTOIGNITION OF CARBOXYLATE -NITRATE GELS”Mater. Lett. 20, 63-69 (1994)

20 M. Schiessl, E. Ivers-Tiffee and W. Wersing, 2607-2614 in Materials
Science Monograths, Vol. 66D, Ceramic Today-Tomorrow’s Ceramics.
Edited by P. Vincenzini. Proceeding of the 7th International Meeting on
Modern Ceramics Technologies (7th CIMTEC-World Ceramics Congress
1990), Elsevier Sience, New York, (1991)

21 N. Zhang, W. P. Ding, Z. B. Guo, W. Zhong, D. Y. Xing, Y. W. Du, G. Li
and Y. Zhang, Zeitschrift fur physik B, vol. 102, Issue 4, 461-465 (1997)

22 M. J. Villafuerte, S. Duhalde, M. C. Terzzoli, G. Polla, G. Leyva, L.
Correra, Appl. Phys. A(Materials Science & Proceeding), vol. 69, Issue 7,
565-567(1999)

23 K. Wiik, C. R. Schmidt, S. Faaland, S. Shamsili, M. A. Einarsrud,* and T. Grande*, “Reactions between Strontium-Substituted Lanthanum Manganite and Yttria-Stabilized Zirconia: I, Powder Samples” J. Am. Ceram. Soc., 82 [3], 721–28 (1999)

24 K. Kleveland, M. A. Einarsrud,* C. R. Schmidt, S. Shamsili, S. Faaland, K. Wiik, and T. Grande* “Reactions between Strontium-Substituted Lanthanum Manganite and Yttria-Stabilized Zirconia: II, Diffusion Couples” J. Am. Ceram. Soc., 82 [3], 729–34 (1999)

25 C. Moure, M. Villegas, J. F. Fernadez, J. Tartaj, and P. Duran “phase transition and electrical conductivity in the system YMnO3-CaMnO3”, J. Mater. Sci., 34, 2565(1999)

26 T. J. Huang, Y. S. Huang “Electrical conductivity and YSZ reactivity of Y1−xSrxMnO3 as SOFC cathode material ” Materials Science and Engineering B, 103, 207–212 (2003)

27 C. Xia, Y. Zhang, and M. Liu “Composite cathode based on yttria stabilized bismuth oxide for low-temperature solid oxide fuel cells” APPLIED PHYSICS LETTERS, VOLUME 82, NUMBER 6

28 C. Sun, R. Hui and J. Roller “Cathode materials for solid oxide fuel cells: a review” J Solid State Electrochem, 14:1125-1144 (2010)

29 Z. Jiang, L. Zhang, L. Cai and C. Xia “Bismuth oxide-coated (La,Sr)MnO3 cathodes for intermediate temperature solid oxide fuel cells with yttria-stabilized zirconia electrolytes” Electrochimica Acta, 54, 3059–3065(2009)

30 J. Li, S. Wang, R. Liu, Z. Wang and J.Q. Qian “Electrochemical performance of (Bi2O3)1-x(Er2O3)x-Ag composite material for intermediate temperature solid oxide fuel cell cathode ” Solid State Ionics 179 1597–1601(2008)

31 Z. Jiang, L. Zhang, K. Feng and C. Xia “Nanoscale bismuth oxide impregnated (La,Sr)MnO3 cathodes for intermediate-temperature solid oxide fuel cells” Journal of Power Sources, 185, 40-48(2008)

32 A. Jaiswal and E. D. Wachsman “Impedance studies on bismuth-ruthenate-based electrodes” Ionics 15:1–9 (2009)

33 V. V. Kharton, E. N. Naumovich and V. Y. Samokhval “Formation and properties of reaction layers of cobaltite electrodes on bismuth oxide electrolytes” Solid State Ionics, 99, 269-280 (1997)

34 J. C. Boivin, C. Pirovano, G. Nowogrocki, G. Mairesse, Ph. Labrune and G. Lagrange, “Electrode–electrolyte BIMEVOX system for moderate temperature oxygen separation” Solid State Ionics, 113-115, 639-651. (1998)

35 D.Y.Wang, A.S.Nowick, J.Elevyro.Soc.,7,126,p.1155-1165(1979)

36 I.Riess, M.Godickemeier, L.J.Gauckler, Solid state Ionics,90,p.91-104 (1996)

37 E.M.Dudnik,V.K.Oganesyan,Institute of materials problems,Academy of Sciences,Ukr SSR Translated from Poroshkovaya Metallurgiya,No.2(38)

38 V. S. Gaviko*, A. V. Korolev*, V. E. Arkhipov*, N. G. Bebenin*, and Ya. M. MukovskiÏ** “X-ray Studies of the (La,Sr)MnO3 Perovskite Manganite Structure” Physics of the Solid State, Vol. 47, No. 7, 2005, pp. 1299–1305

39 F. Y. Shih, K. Z. Fung and T. K. Tseng, “Phase Evolution and Electrical Conductivity of Strontium-doped YMnO3”, 206th Meeting of The Electrochemical Society, Inc., Hawaii, USA, 2004

40 H. Uchida, S. Arisaka, and M. Watanabe, Electrochem. Solid-State Lett., 2, (1999) 428.

41 H. Uchida, S. Arisaka, and M. Watanabe, Solid State Ionics, 135, (2000) 347

42 H. Uchida, H. Suzuki, and M. Watanabe, J. Electrochem. Soc. 145, (1998) 615

43 H. Uchida, T.Osuga, and M. Watanabe, J. Electrochem. Soc. 146, (1999) 1677.

44 H. Uchida, M. Yoshida, and M. Watanabe, J. Electrochem. Soc. 146, (1999) 1.

45 O. Yamamoto, Y. Takeda, R. Kanno, and M. Noda, Solid State Ionics, 22, (19887) 241

46 B. C. H. Steele, Solid State Ionics, 86-88, (1996) 1223

47 Y. Ohno, S. Nagata, and H. Sato, Solid State Ionics, 3/4, (1981) 439.

48 H. Uchida, S. Arisaka, and M. Watanabe, J. Electrochem. Soc. 149, (2002) A13.

49 H. Fukunaga, M. Koyama, and N. Takita, J. Electrochem. Soc. 142 (1995), p. 1519

50 M. J. Jørgensen, and M. Mogensen, J. Electrochem. Soc. 148, (2001) A433

51 黃崇真，“氧化鈮摻雜對(Bi2O3)0.73(MO)0.27 (M=Ca, Sr, Ba)氧離子導體相變及導電性質之影響”，國立成功大學材料科學及工程學系碩士論文，中華民國九十八年。

52 J. Schoonman, J. P. Dekker, J. W. Broers, and N. J. Kiwiet, Solid State Ionics, 46, (1991) 299

53 V. E. J. van Dieten and J. Schoonman, Solid State Ionics, 57, (1992) 141

54 C. C. Chen, M. M. Nasrallah, and H. U. Anderson, Solid State Ionics, 70-71, (1994) 101

55 T. Hibino, A. Hashimoto, K. Asano, M. Yano, M. Suzuki, and M. Sano, Electrochem. Solid-State Lett. 5, (2002) A242.

56 Z. Shao and S. M. Haile, Nature, 431, (2004) 170

57 F. H. van Heuveln and H.J.M. Bouwmeester, J. Electrochem. Soc., 144, (1997) 134

58 B. C. H. Steele, Solid State Ionics, 134, (2000) 3

59 S. P. Jiang, J. Power Sources, 124, (2003) 390