本研究利用銀與靜電紡絲技術製備之La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)奈米纖維均勻混合後，作為質子傳輸型固態氧化物燃料電池之複合陰極。銀價格低廉且具有優良的導電性與催化性，但是銀顆粒在高溫下容易粗化，造成陰極孔隙率降低，導致固態氧化物燃料電池陰極性能降低。故本研究將銀與LSCF奈米纖維均勻混合形成複合陰極，藉由測量不同混合比例下銀與LSCF奈米纖維之電池性能，及電化學交流阻抗頻譜量測，以釐清陰極端中氣體、氧離子、電子與質子之反應機制。
實驗結果顯示，六種組成比例參數中，以50%Ag-50%LSCF(Fiber)具有最佳電池性能，在800 ℃下最大功率密度值為212.90 mW/cm2，而參考試片100%Ag在800 ℃下最大功率密度值為138.04 mW/cm2，電池性能提升54%；於800 ℃下，50%Ag-50%LSCF(Fiber)之極化阻抗為0.076 Ω∙cm2，而100%Ag之極化阻抗為0.339 Ω∙cm2，故LSCF奈米纖維能夠有效提升電池性能與降低極化阻抗，同時提升全電池之長時間性能穩定性。
本文同時提出銀添加LSCF奈米纖維提升電池性能之機制：藉由LSCF奈米纖維抑制銀顆粒成長，同時擔任銀顆粒之間氧離子與電子之傳輸路徑。

In this study, silver and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) nanofibers prepared by electrospinning technology are evenly mixed and used as composite cathodes for proton-conducting solid oxide fuel cells (P-SOFCs). Silver is inexpensive and has excellent conductivity, however, the easy agglomeration of silver particles at high temperature reduces the cathode porosity resulting poor P-SOFC performance. We expect to improve the performance of solid oxide fuel cells using the blending of silver and LSCF nanofibers as composite cathodes in cells. In this study, cell performance (I-V curve) and electrochemical impedance spectroscopy (EIS) clarify the reaction mechanism of gas, oxygen ions, electrons and protons transport in the cathode.
The experimental results show that there exists the best cell performance in the 50%Ag-50%LSCF(Fiber) among six composition ratios. Results show that at 800 ℃, 50%Ag-50%LSCF(Fiber) exhibits higher cell performance and lower polarization impedance of 212.90 mW/cm2 and 0.076 Ω·cm2 compared to other proportions along with 100% Ag reference cell. Therefore, adding LSCF nanofibers can effectively improve the cell performance and long-term stability.
Mixing silver and LSCF nanofibers uniformly, LSCF nanofibers can effectively inhibit the agglomeration of silver particles, and simultaneously act as a transport path of oxygen ions and electrons between silver particles, so that LSCF nanofibers can be practically used in solid oxide fuel cells.

[1] W.R. Grove, “On voltaic series and the combination of gases by platinum”, Philosophical Magazine Series 3, Vol. 14, pp. 127-130, (1839).
[2] G. Hoogers, “Fuel cell technology handbook. CRC press”, (2002).
[3] 黃鎮江，「燃料電池」，全華科技圖書股份有限公司，2005.
[4] J. Sunarso, “Perovskite oxides applications in high temperature oxygen separation, solid oxide fuel cell and membrane reactor: a review”, Progress in Energy and Combustion Science, Vol. 61, pp. 57-77, (2017).
[5] A.L. Lee, R.F. Zabransky, W.J. Huber, “Internal reforming development for solid oxide fuel cells”, Industrial & Engineering Chemistry Research, Vol. 29, pp. 766-773, (1990).
[6] L.M. Zhang, W.S. Yang, “Direct ammonia solid oxide fuel cell based on thin proton-conducting electrolyte”, Journal of Power Sources, Vol. 179, pp. 92-95, (2008).
[7] M. Zunic, L. Chevallier, A. Radojkovic, G. Brankovic, Z. Brankovic, E.D. Bartolomeo, “Influence of the ratio between Ni and BaCe0.9Y0.1O3-δ on microstructural and electrical properties of proton conducting Ni- BaCe0.9Y0.1O3-δ anodes”, Journal of Alloys and Compounds, Vol. 509, pp. 1157-1162, (2011).
[8] B.H. Rainwater, M.F. Liu, M.L. Liu, “A more efficient anode microstructure for SOFCs based on proton conductors”, International Journal of Hydrogen Energy, Vol. 37, pp. 18342-18348, (2012).
[9] L. Bi, E. Fabbri, E. Traversa, “Effect of anode functional layer on the performance of proton-conducting solid oxide fuel cells (SOFCs)”, Electrochemistry Communications, Vol. 16, pp. 37-40, (2012).
[10] K. Xie, R.Q. Yan, X.Q. Liu, “A novel anode supported BaCe0.4Zr0.3Sn0.1Y0.2O3-δ electrolyte membrane for proton conducting solid oxide fuel cells”, Electrochemistry Communications, Vol. 11, pp. 1618-1622, (2009).
[11] H. Moon, S.D. Kim, E.W. Park, S.H. Hyun, H.S. Kim, “Characteristics of SOFC single cells with anode active layer via tape casting and cofiring”, International Journal of Hydrogen Energy, Vol. 33, pp. 2826-2833, (2008).
[12] Z.H. Chen, R. Ran, W. Zhou, Z.P. Shao, S.M. Liu, “Assessment of Ba0.5Sr0.5Co1-yFeyO3-δ (y = 0.0-1.0) for prospective application as cathode for IT-SOFCs or oxygen permeating membrane”, Electrochimica Acta, Vol. 52, pp. 7343-7351, (2007).
[13] C.A.J. Fisher, M. Yoshiya, Y. Iwamoto, J. Ishii, M. Asanuma, K. Yabuta, “Oxide ion diffusion in perovskite-structured Ba1-xSrxCo1-yFeyO2.5: a molecular dynamics study”, Solid State Ionics, Vol. 177, pp. 3425-3431, (2007).
[14] W. Zhou, R. Ran, Z.P. Shao, R. Cai, W.Q. Jin, N.P. Xu, J.M. Ahn, “Electrochemical performance of silver-modified Ba0.5Sr0.5Co0.8Fe0.2O3-δ cathodes prepared via electroless deposition”, Electrochimica Acta, Vol. 53, pp. 4370-4380, (2008).
[15] B. Wei, Z. Lü, X.Q. Huang, J.P. Miao, X.Q. Sha, X.S. Xin, W.H. Su, “Crystal structure, thermal expansion and electrical conductivity of perovskite oxides BaxSr1-xCo0.8Fe0.2O3-δ (0.3 ≤ x ≤ 0.7)”, Journal of the European Ceramic Society, Vol. 26, pp. 2827-2832, (2006).
[16] H.A. Taroco, J.A.F. Santos, R.Z. Domingues, T. Matencio, “Ceramic materials for solid oxide fuel cells”, Advances in Ceramics - Synthesis and Characterization, Processing and Specific Applications, Chapter 19, (2011).
[17] S.M. Haile, G. Staneff, K.H. Ryu, “Non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites”, Journal of Materials Science, Vol. 36, pp. 1149-1160, (2001).
[18] A. Arabacı, M.F. Öksüzömer, “Preparation and characterization of 10 mol% Gd doped CeO2 (GDC) electrolyte for SOFC applications”, Ceramics International, Vol. 38, pp. 6509-6515, (2012).
[19] L.P. Li, J.C. Nino, “Ionic conductivity across the disorder-order phase transition in the SmO1.5-CeO2 System”, Journal of the European Ceramic Society, Vol. 32, pp. 3543-3550, (2012).
[20] J. Sunarso, S.S. Hashim, N. Zhu, W. Zhu, “Perovskite oxides applications in high temperature oxygen separation, solid oxide fuel cell and membrane reactor: a review”, Progress in Energy and Combustion Science, Vol. 61, pp. 57-77, (2017).
[21] T. Takahashi, H. Iwahara, “Ionic conduction in perovskite-type oxide solid solution and its application to the solid electrolyte fuel cell”, Energy Conversion, Vol. 11, pp. 105-111, (1971).
[22] K.D. Kreuer, “Proton-conducting oxides”, Annual Review of Materials Research, Vol. 33, pp. 333-359, (2003).
[23] T. Norby, Y. Larring, “Concentration and transport of protons in oxides”, Current Opinion in Solid State and Materials Science, Vol. 2, pp. 593-599, (1997).
[24] E. Traversa, E. Fabbri, “Proton conducting for solid oxide fuel cells (SOFCs)”, Functional Materials for Sustainable Energy Applications.
[25] Świerczek, Konrad, Wojciech Skubida, “Optimization of proton conductors for application in solid oxide fuel cell technology” E3S Web of Conferences, Vol. 14, (2017).
[26] K. Katahira, Y. Kohchi, T. Shimura, H. Iwahara, “Protonic conduction in Zr　substituted BaCeO3”, Solid State Ionics, Vol. 138, pp. 91-98, (2000).
[27] K.H. Ryu, S.M. Haile, “Chemical stability and proton conductivity of doped BaCeO3 -BaZrO3 solid solutions”, Solid State Ionics, Vol. 125, pp. 355-367, (1999).
[28] W.J. Zheng, C. Liu, Y. Yue, W.Q. Pang, “Hydrothermal synthesis and characterization of BaZr1-xMxO3-α (M = Al, Ga, In, x≦0.20) series oxides”, Materials Letters, Vol. 30, pp. 93-97, (1997).
[29] J. Sui, L. Cao, Q. Zhu, L. Yu, Q. Zhang, L. Dong, “Effects of proton-conducting electrolyte microstructure on the performance of electrolyte-supported solid oxide fuel cells”, Journal of Renewable and Sustainable Energy, Vol. 5, (2013).
[30] R.B. Cervera, Y. Oyama, S. Yamaguchi, “Low temperature synthesis of nanocrystalline proton conducting BaZr0.8Y0.2O3−δ by sol–gel method”, Solid State Ionics, Vol. 178, pp. 569-574, (2007).
[31] W. Zhou, Z.P. Shao, R. Ran, H.X. Gu, W.Q. Jin, N.P. Xu, “LSCF nanopowder from cellulose-glycine-nitrate process and its application in intermediate-temperature solid-oxide fuel cells”, The American Ceramic Society, Vol. 91, pp. 1155-1162, (2008).
[32] X. Zhu, Z. Lü, B. Wei, X. Huang, Y. Zhang, W. Su, “A symmetrical solid oxide fuel cell prepared by dry-pressing and impregnating methods”, Journal of Power Sources, Vol. 196, pp. 729-733, (2011).
[33] M. Jabbari, R. Bulatova, A.I.Y. Tok, C.R.H. Bahl, E. Mitsoulis, J.H. Hattel, “Ceramic tape casting: a review of current methods and trends with emphasis on rheological behaviour and flow analysis”, Materials Science and Engineering: B, Vol. 212, pp. 39-61, (2016).
[34] J.M. Serra, W.A. Meulenberg, “Thin‐film proton BaZr0.85Y0.15O3 conducting electrolytes: toward an intermediate‐temperature solid oxide fuel cell alternative”, Journal of the American Ceramic Society, Vol. 90, pp. 2082-2089, (2007).
[35] S. Ahmadi, N. Asim, M.A. Alghoul, F.Y. Hammadi, K. Saeedfar, N.A. Ludin, S.H. Zaidi, K. Sopian, “The role of physical techniques on the preparation of photoanodes for dye sensitized solar cells”, International Journal of Photoenergy, Vol. 2014, (2014).
[36] H.S. Noh, K.J. Yoon, B.K. Kim, H.J. Je, H.W. Lee, J.H. Lee, J.W. Son, “The potential and challenges of thin-film electrolyte and nanostructured electrode for yttria-stabilized zirconia-base anode-supported solid oxide fuel cells”, Journal of Power Sources, Vol. 247, pp. 105-111, (2014).
[37] Arda Aytimur, Serhat Kocyig˘it, Ibrahim Uslu, “Calcia stabilized ceria doped zirconia nanocrystalline ceramic”, Journal of Inorganic and Organometallic Polymers and Materials, Vol. 24, pp. 927-932, (2014).
[38] M.F. Ashby, “A first report on sintering diagrams”, Acta Metallurgica, Vol. 22, pp. 275-289, (1974).
[39] Baharuddin, Nurul Akidah, Andanastuti Muchtar, Mahendra Rao Somalu, “Short review on cobalt-free cathodes for solid oxide fuel cells”, International Journal of Hydrogen Energy, Vol. 42, pp. 9149-9155, (2017).
[40] Jaka Sunarso, Siti Salwa Hashim, Na Zhu, Wei Zhou, “Perovskite oxides applications in high temperature oxygen separation, solid oxide fuel cell and membrane reactor: a review”, Progress in Energy and Combustion Science, Vol. 61, pp. 57-77, (2017).
[41] R.R. Peng, T.Z. Wu, W. Liu, X.Q. Liu, G.Y. Meng, “Cathode processes and materials for solid oxide fuel cells with proton conductors as electrolytes”, Journal of Materials Chemistry, Vol. 20, pp. 6218-6225, (2010).
[42] Shichen Suna, Zhe Cheng, “Electrochemical behaviors for Ag, LSCF and BSCF as oxygen electrodes for proton conducting IT-SOFC”, Journal of The Electrochemical Society, Vol. 164, pp. F3104-F3113, (2017).
[43] EG & G Technical Services Inc., Fuel Cell Handbook 7th Eds, U.S., Department of Energy, (2004).
[44] Rungsima Yeetsorn, Michael W. Fowler, Costas Tzoganakis, “A review of thermoplastic composites for bipolar plate materials in PEM fuel cells”, Nanocomposites With Unique Properties and Applications in Medicine and Industry, (2011).
[45] Sekar, Narendran, P. Ramasamy, “Electrochemical impedance spectroscopy for microbial fuel cell characterization”, J. Microb. Biochem. Technol, Vol. 6.2, (2013).
[46] N.Y. Hsu, S.C. Yen, K.T. Jeng, C.C. Chien, “Impedance studies and modeling of direct methanol fuel cell anode with interface and porous structure perspectives”, Journal Power Sources, Vol. 161, pp. 232, (2006).
[47] S.T. Aruna, L.S. Balaji, S. Senthil Kumar, B. Shri Prakash, “Electrospinning in solid oxide fuel cells - a review”, Renewable and Sustainable Energy Reviews, Vol. 67, pp. 673-682, (2017).
[48] Ke Chen, Weimin Chou, Lichao Liu, Yonghui Cui, Ping Xue, Mingyin Jia, “Electrochemical sensors fabricated by electrospinning technology: an overview”, sensors, Vol. 17, pp. 3676, (2019).
[49] Rezaei, Atefe, Ali Nasirpour, Milad Fathi, “Application of cellulosic nanofibers in food science using electrospinning and its potential risk”, Comprehensive Reviews in Food Science and Food Safety, Vol. 14, pp. 269-284, (2015).