本論文使用已建立之高壓測試平台，搭配鈕扣型實驗載具，針對加壓型SOFC陽極支撐全電池(Ni-YSZ/YSZ/LSC)，量測其使用甲烷燃氣所產生之碳沉積效應，以及相關之性能曲線(I-V curve)與電化學阻抗頻譜(Electrochemical Impedance Spectra, EIS)。實驗條件為固定氣體流率(陽極50 sccm CH4+150 sccm N2和陰極200 sccm Air)，並控制電池負載(0.9和0.8V)、系統操作壓力(p = 1和3atm)和系統溫度(T = 750和800oC)。結果顯示，壓力和溫度增加皆會使電池性能有效提升，兩者皆可使總極化阻抗減小，但歐姆阻抗則與加壓效應無關，其僅會隨溫度增加而下降。
為詳細探討電池負載、加壓和溫度效應對於碳沉積之影響，我們進一步作性能穩定性測試。結果顯示，當電池在較高的負載下，可有效抑制碳沉積的產生，例如:在溫度800oC與壓力1 atm下時，0.8V可穩定操作達120分鐘，0.9V則會隨時間持續衰退無法穩定。加壓和升溫理論上會加快碳沉積形成之速率，但因電池性能會同時受加壓和升溫影響而提升，故提高了水與二氧化碳的濃度，它們可增加除碳作用。整體電池性能是否可達到穩定，必須取決於壓力、溫度和電池負載間的交互影響。最後，使用氫氣移除碳沉積，證實碳沉積可被氫氣移除，但移除後電池性能較移除前低。這可能是因為碳沉積已些微破壞電池微結構，造成無法完全回復原電池性能。本研究結果，應有助於了解加壓型SOFC使用甲烷燃氣所形成之碳沉積現象，值得一提的事，本研究為國際上首度利用實驗，來進行壓力效應對碳沉積之研究，這對未來開發加壓型SOFC與微氣渦輪機複合式發電系統應有所助益。

This study applies an established high-pressure SOFC testing platform together with a button cell experimental setup, so that the impact of carbon deposition on the cell performance, electrochemical impedance spectroscopy (EIS), and stability tests of an anode-supported button full cell can be analyzed when using methane as a fuel. Fixed flow rates are used for all experiments (CH4 + N2: 50 +150 = 200 sccm in anode and air: 200 sccm in cathode) at two different cell loads (0.9V, 0.8V), temperatures (750, 800oC) and pressures (1, 3atm). Results show that cell power densities increase with increasing p and T. It found that the ohmic polarization resistance is independent of p, but it decreases with increasing T. The total polarizaiton resistances decrease with increasing T and p.
To investigate effects of operational parameters i.e. cell loading, temperature, and pressure on carbon deposition, we further conduct the stability test of the cell performance. Results suggest that increasing the cell loading can inhibit effectively carbon deposition. For example, when T = 800oC and p = 1 atm, the cell performance is stable at 0.8V for at least 120 minutes but degradation of performance is found at 0.9V. Though increasing T and p can promote methane cracking rate, cell performance can be also enhanced simultaneously resulting in higher concentrations of H2O and CO2 that remove carbon effectively. Therefore, the stability of cell performance depends on interactions of cell loading, temperature, and pressure. After the stability test of cell performance, we apply hydrogen for the reduction of carbon deposition. The result shows that carbon can be removed by using hydrogen but the original performance can not be fully recovered. The present study should be useful for understanding the carbon deposition phenomenon when using methane as the anode fuel. Generally, the power density increases due to pressurization. However, the effect of pressure must be combined with loading and temperature effects to determine whether cell performance can be stable. To the best knowledge of the authors, it is worth of noting that the aforesaid pressurization effect on carbon deposition is the first available experimental investigation in literatures, which should be useful in the development of pressurized SOFC integrating with micro gas turbines for hybrid power generation systems.

. L. Lee, R. F. Zabransky, W. J. Huber, Internal Reforming Development for Solid Oxide Fuel Cells, Industrial & Engineering Chemistry, Vol. 29, pp. 766-773, 1990.
[2] E. P. Murray, T. Tsai, S. A. Barnett, A direct-methane fuel cell with a ceria-based anode, Nature, Vol. 400, pp. 649-561, 1999.
[3] T. Suzuki, T. Yamaguchi, K. Hamamoto, Y. Fujishiro, M. Awanoa, N. Sammes, A functional layer for direct use of hydrocarbon fuel in low temperature solid-oxide fuel cells, Energy & Environmental Science, Vol. 144, pp. 940-943, 2011.
[4] G. L. Semin, V. D. Belyaev, A. K. Demin, V. A. Sobyanin, Methane conversion to syngas over Pt-based electrode in a solid oxide fuel cell reactor, Applied Catalysis A: General, Vol. 181, pp. 131-137, 199.
[5] S. C. Singhal, Advances in solid oxide fuel cell technology, Solid State Ionics, Vol. 135, pp. 305-313, 2000.
[6] Y. Kobayashi, Y. Ando, T. Kabata, M. Nishiura, K. Tomida, N. Matake, Extremely high efficiency thermal power system-solid oxide fuel cell (SOFC) triple combined-cycle system, Mitsubishi Heavy Industries Technical Review, Vol. 48, pp. 9-15, 2011.
[7] W. L. Lundberg, S. E. Veyo, M. D. Moeckel, A high-efficiency solid oxide fuel cell hybrid power system using the Mercury 50 advanced turbine systems gas turbine, Journal of Engineering for Gas Turbines and Power, Vol. 125, pp. 51-58, 2002.
[8] S. K. Park, T. S. Kim, Comparison between pressurized design and ambient pressure design of hybrid solid oxide fuel cell–gas turbine systems, Journal of Power Sources, Vol. 163, pp. 490–499, 2006.
[9] S. E. Veyo, L. A. Shockling, J. T. Dederer, J. E. Gillet, W. L. Lundberg, Tubular solid oxide fuel cell/gas turbine hybrid cycle power system: Status, Journal of Engineering for Gas Turbines and Power, Vol. 124, pp. 845-849, 2002.
[10] Y. Lin, Z. Zhan, J. Liu, S. A. Barnett, Direct operation of solid oxide furl cells with methane fuel, Solid State Ionics, Vol. 176, pp. 1827-1835, 2005.
[11] T. Kim, G. Liu, M. Boaro, S. -I, Lee, J. M. Vohs, R. J. Gorte, O. H. Al-Madhi, B. O. Dabbousi, A study carbon formation and prevention in hydrocarbon-fueled SOFC, Journal of Power Sources, Vol. 155, pp. 231-238, 2006.
[12] T. S. Doyle, Z. Dehouche, P. V. Aravind, M. Liu, S. Stankovic, Investigating the impact and reaction pathway of toluene on a SOFC running on syngas, International Journal of Hydrogen Energy, Vol. 39, pp. 12083-12091, 2014.
[13] R. Suwanwarangkul, E. Croiset, E. Entchev, S. Charojrochkul, M. D. Pritzker, M. W. Fowler, P. L. Douglas, S. Chewathanakup, H. Mahaudon, Experimental and modeling study of solid oxide fuel cell operating with syngas fuel, Journal of Power Sources, Vol. 161, pp. 308-322, 2006.
[14] Y. Shiraton, T. Ijichi, T. Oshima, K. Sasaki, Internal reforming SOFC running on biogas, International Journal of Hydrogen Energy, Vol. 35, pp. 7905-7912, 2010.
[15] G. Goula, V. Kiousis, L. Nalbandian, I. V. Yentekakis, Catalytic and electrocatalytic behavior of Ni-based cermet anodes under internal dry reforming of CH4+CO2 mixtures in SOFCs, Solid State Ionics, Vol.177, pp. 2119-2123, 2006.
[16] M. A. Buccheri, A. Singh, J. M. Hill, Anode- versus electrolyte-supported Ni-YSZ/YSZ/Pt SOFCs: Effect of cell design on OCV, performace and carbon formation for the direct utilization of dry methane, Journal of Power Sources, Vol. 193, pp. 968-976, 2011.
[17] J. -H. Koh, Y. -S. Yoo, J. -W. Park, H. C. Lim, Carbon deposition and cell performance of Ni-YSZ anode support SOFC with methane fuel, Solid State Ionics, Vol. 149, pp. 157-166, 2002.
[18] J. Liu, S. A. Barnett, Operation of anode-supported solid oxide fuel cells on methane and natural gas, Solid State Ionics, Vol. 158, pp. 11-16, 2003.
[19] C. M. Finnerty, R. M. Ormerod, Internal reforming over nickel/zirconia anodes in SOFCS operating on methane: influence of anode formulation, pre-treatment and operating conditions, Journal of Power Sources, Vol. 86 pp. 390-394, 2000.
[20] R. Kikuchi, T. Yano, T. Takeguchi, K. Eguchi, Characteristics of anodic polarization of solid oxide fuel cells under pressurized conditions, Solid State Ionics, Vol.174, pp. 111-117, 2004.
[21] L. A. Chick, O. A. Marina, C. A. Coyle, E. C. Thomsen, Effects of temperature and pressure on the performance of a solid oxide fuel cell running on steam reformate of kerosene, Journal of Power Sources, Vol. 236, pp. 1-9, 2012.
[22] S. Seidler, M. Henke, J. Kallo, W. G. Bessler, U. Maier, K. A. Friedrich, Pressurized solid oxide fuel cells: Experimental studies and modeling, Journal of Power Sources, Vol. 196, pp. 7195-7202, 2011.
[23] M. Henke, J. Kallo, W. G. Bessler, Influence of pressurisation on SOFC performance and durability: A theoretical study, Fuel Cells, Vol. 11, pp. 581-591, 2011.
[24] P. C. Wu, H. S. Jheng, S. S. Shy, Electrochemical Impedance Measurement and Analysis of Anodic Concentration Polarization for Pressurized Solid Oxide Fuel Cells, Journal of The Electrochemical Society, Vol. 161(4), F513-F517, 2014.
[25] S. Shy, Y. D. Hsieh, C. M. Huang, Y. H. Chan, Comparison of Electrochemical Impedance Measurements between Pressurized Anode-Supported and Electrolyte Planar Solid Oxide Fuel Cells, Journal of The Electrochemical Society, Vol. 162(3), F1-F6, 2015.
[26] B. Huang, X. F. Ye, S. R. Wang, H. W. Nie, J. Shi, Q. Hu, J. Q. Qian, X. F. Sun, T. L. Wen, Performance of Ni/ScSZ cermet anode modified by coating with Gd0.2Ce0.8O2 for an SOFC running on methane fuel, Journal of Power Sources, Vol. 162, pp. 1172-1181, 2006
[27] H. Kim, C. Lu, W. L. Worrell, J. M. Vohs, R. J. Gorte, Cu-Ni Cermet Anodes for Direct Oxidation of Methane in Solid-Oxide Fuel Cells, Journal of The Electrochemical Society, Vol. 149(3), pp. A247-A250, 2002.
[28] C. A. Lozano, M. Ohashi, S. Shimpalee, J. W. V. Zee, P. Aungkavattana, Comparison of Hydrogen and Methane as fuel in Micro-Tubular SOFC using Electrochemical Analysis, Journal of The Electrochemical Society, Vol. 158(10), pp. B1235-B1245, 2011.
[29] M. K. Bruce, M. V. D. Bossche, S. McIntosh, The Influence of Current Density on the Electrocatalyric Activity of Oxide-Based Direct Hydrocarbon SOFC Anodes, Journal of The Electrochemical Society, Vol. 155(11), B1202-B1209, 2008.
[30] M. Pillai, Y. Lin, H. Zhu, R. J. Kee, S. A. Barnett, Stability and coking of direct-methane solid oxide fuel cells: Effect of CO2 and air additions, Journal of Power Sources, Vol. 195, pp. 271-279, 2010.
[31] W. Wang, R. Ran, C. Su, Y. Guo, D. Farrusseng, Z. Shao, Ammonia-mediated suppression of coke formation in direct-methane solid oxide fuel cells with nickel-based anodes, Journal of Power Sources, Vol. 240, pp. 232-240, 2013.
[32] 鄭浩昇，加壓型固態氧化物燃料電池量測與分析：壓力、溫度與質量流率效應，碩士論文，國立中央大學，2012。
[33] 謝易達，加壓型SOFC陽極支撐與電解質支撐單電池堆量測與分析，碩士論文，國立中央大學，2013。
[34] 吳佩真，加壓鈕扣型陽極支撐SOFC實驗量測與活化和濃度過電位分析計算，碩士論文，國立中央大學，2013。
[35] 李雪茹，加壓SOFC陰極半電池實驗研究，碩士論文，國立中央大學，2013。
[36] 詹彥信，固態氧化物燃料電池使用甲烷燃氣之性能和電化學阻抗頻譜實驗研究，碩士論文，國立中央大學，2014。
[37] V. Subotic, C. Schluckner, C. Hochenauer, An experimental and numeral study of performance of large planar ESC-SOFCs and experimental inverstigation of carbon depositions, Journal of the Energy Institute, pp. 1-17, 2015.
[38] M. Mogensen, K. Kammer, Conversion on Hydrocarbon in Solid Oxide Fuel Cells, Annual Review of Materials Research, Vol. 33, pp. 321-331, 2003.
[39] H. Aslannejad, S. Bozorgmechri, A. Babaei, H. Mohebbi, A. Ghobadzadeh, A. Haghparast, S. Davari, Effect of Operational Condition on Performance and Durability of Solid Oxide Fuel Cell Fueled By Natural Gas, ECS Transactions, Vol. 57(1), pp. 2939-2946, 2013.
[40] S. C. Singal, Solid oxide fuel cell for stationary, mobile, and military applications, Solid State Ionics, Vol. 152 pp. 405-410, 2002.
[41] X. Xu, Z. Jiang, X. Fan, C. Xia, LSM-GDC electrodes fabricated with an ion-impregnating process for SOFCs with doped ceria electrolytes, Solid State Ionics, Vol. 177, pp. 2113-2117, 2006.
[42] M. Mogensen, K.V. Jensen, M. J. Jørgensen, S. Primdahl, Progress in understanding SOFC electrodes, Solid State Ionics, Vol. 150, pp. 123-129, 2003.
[43] J. Larminie, A. Dicks, Fuel Cell Systems Explained, 2nd ED., John Wiley & Sons, Inc., West Sussex, 2003.
[44] S. -B. Lee, T. -H. Lim, R. -H. Song, D. -R. Shin, S. -K. Dong, Development of a 700W anode-supported micro-tubular SOFC stack for APU applications, International of Hydrogen Energy, Vol. 33, pp. 2330-2336, 2008.
[45] N. M. Sammes, Y. Du, R. Bove, Design and fabrication of a 100W anode supported micro-tubular SOFC stack, Journal of Power Sources, Vol. 145, pp. 428-434, 2005.
[46] D. Cui, L. Liu, Y. Dong, M. Cheng, Comparison of different current collecting modes of anode supported micro-tubular SOFC through mathematical modeling, Journal of Power Sources, Vol. 174, pp. 246-254, 2007.
[47] S. C. Singhal, Science and Technology of Solid Oxide Fuel Cells, Materials Research Bulletin, Vol. 25, pp. 16-21, 2000.
[48] Y. Patcharavorachot, A. Arpornwichanop, A. Chuachuensuk, Electrochemical study of a planar solid oxide fuel cell: Role of support structures, Journal of Power Sources, Vol. 177, pp. 254-261, 2008
[49] M. M. Hussain, X. Lia, I. Dincer, A general electrolyte–electrode-assembly model for the performance characteristics of planar anode-supported solid oxide fuel cells, Journal of Power Sources, Vol. 189, pp. 916-928, 2009.
[50] D. Sarantaridis, A. Atkinson, Redox Cycling of Ni-Based Solid Oxide Fuel Cell Anodes: A Review, Fuel Cell, Vol. 7, No. 3, pp. 246-258, 2007.
[51] M. Stelter, A. Reinert, B. E. Mai, M. Kuznecov, Engineering aspects and hardware verification of a volume producible solid oxide fuel cell stack design for diesel auxiliary power units, Journal of Power Sources, Vol. 154, pp. 448-455, 2006.
[52] M. Ni, M. K. H. Leung, D. Y. C. Leung, Parametric study of solid oxide fuel cell performance, Energy Conversion and Management, Vol. 48, pp. 1525-1535, 2007.
[53] 李信宏，棋盤式雙極板尺寸流道效應對固態氧化物燃料電池性能之影響，碩士論文，國立中央大學，2010。
[54] S. H. Chan, K. A. Khor, Z. T. Xia, A complete polarization model of a solid oxide fuel cell and its sensitivity to the change of cell component thickness, Journal of Power Sources, Vol. 93, pp. 130-140, 2001.
[55] W. G. Bessler, S. Gewies, Gas concentration impedance of solid oxide fuel cell anodes II. Channel geometry, Journal of The Electrochemical Society, Vol. 154, pp. B548-B559, 2007.
[56] Q. A. Huang, R. Hui, B. Wang, J. Zhang, A review of AC impedance modeling and validation in SOFC diagnosis, Electrochimica Acta, Vol. 52, pp. 8144-8164, 2007.
[57] J. B. Jorcin, M. E. Orazem, N. Pébére, B. Tribollet, CPE analysis by local electrochemical impedance spectroscopy, Electrochemica Acta, Vol. 51, pp. 1473-1479, 2006.
[58] A. Leonide, V. Sonn, A. Weber, E. Ivers-Tiffée, Evaluation and modeling of the cell resistance in anode-supported solid oxide fuel cells, Journal of The Electrochemical Society, Vol. 155, pp. B36-B41, 2008.
[59] J. Ding, J. Liu, G. Yin, Cell/stack electrochemical performance and stability of cone-shaped tubular SOFCs for direct operation with methane, Electrochimica Acta, Vol. 56, pp. 6593-6597, 2011.
[60] V. Subotić, C. Schluckner, C. Hochenauer, An experimental and numerical study of performance of large planar ESC-SOFCs and experimental investigation of carbon depositions, Journal of the Energy Institute, in press.
[61] X. J. Chen, K. A. Khor, S. H. Chan, Suppression of Carbon Deposition at CeO2-Modified Ni/YSZ Anodes in Weakly Humidified CH4 at 850oC, Electrochemical and Solid-State Letters, Vol. 8(2), pp. A79-A82, 2005.
[62] Y. Wang, F. Yoshiba, M. Kawase, T. Watanabe, Performance and effective kinetic models of methane steam reforming over Ni/YSZ anode of planar SOFC, International Journal of Hydrogen Energy, Vol. 34, pp. 3885-3893, 2009.
[63] A. Gunji, C. Wen, J. Otomo, T. Kobayashi, K. Ukai, Y. Mizutani, H. Takahashi, Carbon deposition behavior on Ni-ScSZ anodes for internal reforming solid oxide fuel cells, Journal of Power Sources, Vol. 131, pp. 285-288, 2004.
[64] C. M. Finnerty, R. M. Ormerod, Internal reforming over nickel/zirconia anodes in SOFCS operating on methane: influence of anode formulation, pre-treatment and operating conditions, Journal of Power Sources, Vol. 86, pp. 390-394, 2000.
[65] S. Park, J. M. Vohs, R. J. Gorte, Direct oxidation of hydrocarbons in a solid-oxide fuel cell, Nature, Vol. 404, pp. 265-267, 2000.
[66] Y. Lin, Z. Zhan, S. A. Barnett, Improving the stability of direct-methane solid oxide fuel cells using anode barrier layers, Journal of Power Sources, Vol. 158, pp. 1313-1316, 2006.
[67] T. Ma, M. Yan, M. Zeng, J. -L. Yuan, Q. -Y. Chen, B. Sundén, Q. -W. Wang, Parameter study of transient carbon deposition effect on the performance of a planar solid oxide fuel cell, Applied Energy, Vol. 152, pp. 217-228, 2015.
[68] V. A. C. Haanappel, M. J. Smith, A review of standardising SOFC measurement and quality assurance at FZJ, Journal of Power Sources, Vol. 171, pp. 169-178, 2007.
[69] E. C. Thomsen, G. W. Coffey, L. R. Pederson, O. A. Marina, Performance of lanthanum strontium manganite electrodes at high pressure, Journal of Power Sources, Vol. 191, pp. 217-224, 2009.