(18.232.50.137) 您好!臺灣時間:2021/05/06 18:03
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果

詳目顯示:::

我願授權國圖
: 
twitterline
研究生:吳盈瑩
研究生(外文):Ying-ying Wu
論文名稱:電紡製備Ce0.78Gd0.2Sr0.02O2-δ纖維及其於燃料電池之陽極特性研究
論文名稱(外文):Fabrication and characterization of electrospinning Ce0.78Gd0.2Sr0.02O2-δ fiber and its application in fuel cell
指導教授:周振嘉
指導教授(外文):Chen-Chia Chou
學位類別:碩士
校院名稱:國立臺灣科技大學
系所名稱:機械工程系
學門:工程學門
學類:機械工程學類
論文種類:學術論文
論文出版年:2008
畢業學年度:96
語文別:中文
論文頁數:103
中文關鍵詞:電紡纖維固態氧化物燃料電池
外文關鍵詞:electrospinningfiberSolid Oxide Fuel Cell
相關次數:
  • 被引用被引用:0
  • 點閱點閱:111
  • 評分評分:系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
本研究主要利用靜電紡絲製備異價離子共摻雜之氧化鈰(Ce0.78Gd0.2Sr0.02O2-δ,以下簡稱GDCSr纖維,藉由改變高分子載體濃度、電場強度與不同收集方式得到不同型態的收集物。實驗結果顯示,以轉軸收集器、注射馬達速率1.5ml/hr、電壓20kV、負極與針頭距離12cm、PVP濃度為整體溶液的11.32wt%,可得到直徑均勻和規則排列的100nm左右GDCSr�n纖維。實驗中利用X光繞射儀、掃描式電子顯微鏡、穿透式電子顯微鏡分析GDCSr纖維於不同燒結溫度(800 ℃、1000 ℃、1300 ℃、1500 ℃)之成相性、晶粒尺寸與結晶性。隨著溫度上升,GDCSr纖維內部晶粒也隨著成長,若燒結溫度超過1300 ℃則會破壞GDCSr纖維原始形貌,這顯示了GDCSr纖維陽極燒結溫度必須低於1300 ℃。
將製備GDCSr纖維應用於固態氧化物燃料電池(Solid Oxide Fuel Cell,SOFC)的陽極部分。GDCSr纖維經配製膠體後網印在GDCSr電解質上經高溫去高分子而形成網狀氧離子通路,再以浸鍍法使Ni粒子披覆於網狀氧離子通路上,然後用不同溫度燒結(1000 ℃、1200 ℃、1300 ℃)形成陽極。
陽極網印於GDCSr電解質(厚度0.7mm)並與白金參考電極之半電池,使用燃料氣氛15%H2(Dry,100cc/min)下在400~550 ℃之間,測量AC交流阻抗、鐵弗曲線、半電池之功率密度。
AC交流阻抗於1000 ℃/1hr、1200 ℃/1hr與1300 ℃/1hr三種燒結溫度參數顯示,1200 ℃/1hr陽極燒結溫度在各工作溫度(400~550 ℃)有較低的電極阻抗,經由阻抗值換算陽極活化能亦顯示1200 ℃/1hr燒結有最低陽極活化能(0.86 eV)。鐵弗曲線於各工作溫度下也顯示陽極燒結溫度1200 ℃時,交換電流密度(Io)值最高,同時也有最高功率密度(550 ℃,10.06 mW/cm2)。
另外,經由SEM得知,1200 ℃/1hr陽極燒結溫度,陽極與電解質接合良好且因為燒結溫度較低,使得鎳不易因高溫團聚而降低三相點區域,因此有較高的催化活性,進而得到較低的極化電阻、較高的交換電流密度及功率密度。
最後,利用靜電紡絲法製備GDCSr纖維應用於固態氧化物燃料電池(Solid Oxide Fuel Cell,SOFC)陽極時,發現在高溫及低氧分壓下,其工作溫度無法超越550 ℃及工作效率會下降。由SEM微觀影像發現,GDCSr材料於燃料20%H2(Dry,100cc/min)氣氛下600 ℃持溫2小時還原後,明顯晶粒成長,及TEM顯示以高分辨電鏡影像�vHRTEM)和相同zone axis = [001]逆傅立葉轉換,觀察其微觀區域,GDCSr還原後晶格扭曲和缺陷差排尺寸大小明顯較未還原GDCSr大且多。由於高溫低氧分壓時,氧化鈰變得非常不穩定,Ce3+的離子取代Ce4+,產生電子缺陷被所形成的離子氧空缺所補償,造成過多氧空缺。空缺越多,元素擴散越易,故晶粒容易成長。Ce4+易還原成Ce3+,Ce4+和Ce3+離子半徑差異大,易造成晶格扭曲及差排變多,使得氧離子傳導反而降低,影響整體發電效率。
Ni-Ce0.78Gd0.2Sr0.02O2-δ anode materials, having high ionic conductivity GDCSr fibers and fine Ni particles, sintered at different temperatures were developed for intermediate temperature solid oxide fuel cell application. Electrospinning deposition technique was adopted to produce nano sized GDCSr fibers using PVP as solvent material. Viscosity of the solution and the applied voltage played a significant role to generate long and uniform size fibers. The flow rate of 1.5 litre/h and voltage of 20 kV were maintained throughout the experiment. Fibers of average size of 100nm were generated using a collector placed at a distance of 12 cm. XRD of the GDCSr fiber sintered at different temperatures revealed in cubic phase. Scanning electron micrographs indicate that the size and length of fiber increase with increasing the sintering temperature. The existence of cubic structure and formation of uniform size fibers was confirmed by bright field image and diffraction patterns of transmission electron microscopy. The mixture of fiber and powder at weight of 75:25 was used to screen print on the GDCSr electrolyte. The anode films were prepared via a nickel wet dipping process and sintered at different temperatures. The micrograph of the anode sintered at 1200 ℃/1hr has a well defined microstructure in terms of electrolyte area covered with nickel and the triple phase boundary line between electrolyte, electrode and gas phase. Higher sintering temperature resulted in the formation agglomerates of nickel particles and crack in the films, which might be due to particle size of the initial powder.
Two important aspects for using fiber based anode, the kinetics of the hydrogen oxidation reaction and the effect of the microstructure on the electrochemical performance of the anode. Insight in these two aspects will lead to a better understanding and further improvement of the anode by changing the sintering temperature of the fiber based anode. For electrochemical characterization of the electrodes, impedance and tafel measurements are performed. Impedance measurements performed under standard conditions resulted in spectra, which when analyzed with an equivalent circuit, are built up of two semicircles and are found dominating with sintering temperature. The high frequency semicircle is ascribed to charge transfer phenomenon at the interface of anode and electrolyte and the low frequency semicircle is ascribed to the concentration polarization. The area specific resistance of around 28 ��-cm2 is observed at 550 ℃ for the anode sintered at 1200oC for 1hr. The significant reduction in overall electrode resistance in half cell with anode sintered at 1200 ℃/1hr can be attributed to an increased number of active sites. Moreover, the energy required to activate the electrochemical reaction is lower (0.86eV) in the anode sintered at 1200 ℃. The equivalent circuit constructed by fitting the Cole-Cole plots shows the deviation in the distribution of nickel particles and discontinuity of the interface between electrolyte and anode. Hydrogen oxidation reaction was estimated using tafel curves by calculating the exchange current density. Higher exchange current density of 5.2mA/cm2 was observed in the hall cell for the anode sintered at 1200oC/1hr at all working temperatures from 400 ℃ to 550 ℃. Half cells with fiber anode, bulk electrolyte and Pt cathode were developed. Half cell with anode sintering temperature of 1200 ℃/1h has shown better performance compared to other sintering temperatures, due to increase in triple phase boundary regions with long fiber anodes. The maximum power density of 10.02mW/cm2 is recorded in the voltage-current characteristic curves drawn at different temperatures. Transmission electron microscopy analysis was carried out to identify the reason for the reduce in reduction temperature (600 ℃/2hr) Electrolyte material after reduction has shown larger and higher number of dislocations compared to the electrolyte before reduction. SEM images have shown the difference in grain size. Grain size is found larger after reduction. XRD patterns reveal cubic phase in both materials. This was also confirmed from TEM diffraction pattern. The possible reason might be the addition of higher ionic radii elements such as Sr for Ce, enhances the lattice distortion and to compensate this lattice distortion dislocations are formed in the material. Moreover, the reduction of CeO2 to Ce2O3 has effected in increasing the dislocations in the material due to increase in electronic conductivity. The overall data indicates that the sintering temperature of the fiber anode has a significant effect on electrochemical performance of the half cell.
目錄
摘要 I
Abstract III
目錄 VI
圖表目錄 IX
第一章 緒論 1
1.1 前言 1
1.2 研究動機與目的 2
第二章 文獻回顧 5
2.1 固態氧化物燃料電池回顧 5
2.1.1 固態氧化物燃料電池簡介 5
2.1.2 固態氧化物燃料電池之歷史 6
2.1.3 固態氧化物燃料電池原理 7
2.2 固態氧化物燃料電池之電解質 8
2.2.2 氧化鈰基電解質結構和導電性能 9
2.3 固態氧化物燃料電池之陽極 14
2.3.1 陽極材料及要求 14
2.3.2 陽極操作原理 15
2.4 奈米纖維回顧 16
2.4.1 纖維簡介 16
2.4.2 奈米纖維的製備方法與應用 17
2.4.3 靜電紡絲技術 20
第三章 實驗方法 30
3.1 實驗藥品規格及儀器設備 30
3.2 實驗流程 33
3.3 試片製備 34
3.3.1 電解質製備 34
3.3.2 陰極製備 35
3.3.3 纖維陽極製備 35
3.3.4 試片量測與分析 42
第四章 結果與討論 54
4.1 Ni- Ce0.78Gd0.2Sr0.02O2-δ陶瓷纖維探討 54
4.1.1 電紡絲製程參數對纖維的影響 54
4.1.2 纖維燒結與XRD分析 61
4.1.3 不同燒結溫度對微觀的影響 64
4.1.4 TEM繞射圖形分析 66
4.2 纖維陽極半電池探討 67
4.2.1 Ni- Ce0.78Gd0.2Sr0.02O2-δ陽極纖維燒結不同溫度之晶體結構 68
4.2.2 Ni- Ce0.78Gd0.2Sr0.02O2-δ陽極纖維燒結不同溫度之微觀結構 70
4.2.3 交流阻抗分析Ni- Ce0.78Gd0.2Sr0.02O2-δ陽極纖維燒結不同溫度之極化電阻 74
4.2.4 Ni- Ce0.78Gd0.2Sr0.02O2-δ陽極纖維燒結不同溫度之鐵弗曲線 80
4.2.5 Ni- Ce0.78Gd0.2Sr0.02O2-δ陽極纖維燒結不同溫度之發電效率(power density) 82
4.3 Ce0.78Gd0.2Sr0.02O2-δ的TEM微觀分析 85
第五章 結論 93
參考文獻 98
[1]余河潔. 以鍶摻雜銅酸鑭做為中溫固態氧化物燃料電池陰極材料之研究. 國立成功大學材料科學及工程學系博士論文 2005.
[2]S. G. Solid Electrolytes. Springer-Verlag, 1977.
[3]V HPaCW. Solid electrolytes general principles,characterization, materials, applications. Academic Press 1978.
[4]Inaba H, Tagawa H. Ceria-based solid electrolytes. Solid State Ionics 1996;83:1.
[5]Yahiro H. aKE. Electrial properties and mircostructure in the system ceria-alkaline earth oxide. Journal of Materials Science, 23,1036~1041. 1988.
[6]黃鎮江. 燃料電池: 全華出版社, 2003.
[7]Yahiro H, Eguchi K, Arai H. Ionic conduction and microstructure of the ceria-strontia system. Solid State Ionics 1986;21:37.
[8]Faber J, Geoffroy C, Roux A, Sylvestre A, Abelard P. A Systematic investigation of the dc electrical conductivity of rare-earth doped ceria. Applied Physics A Solids and Surfaces 1989;49:225.
[9]Balazs GB, Glass RS. ac impedance studies of rare earth oxide doped ceria. Solid State Ionics 1995;76:155.
[10]F.R.Foulkes, AAJa. Fuel cell hand book: Van Nostrand Reinhold, 1989.
[11]H. G. Fuel cell technology hand book: CRC Press, 2002.
[12]A.Atkinson VVKea. Solid State Ionics 2004:174.
[13]Zhang Tianshu PH, Haitao Huang, J. Kilner,. Ionic conductivity in the CeO2–Gd2O3 system (0.05 Gd/Ce 0.4) prepared by oxalate coprecipitation. Solid State Ionics 148 2002:p567.
[14]Zhang TS, Ma J, Kong LB, Chan SH, Hing P, Kilner JA. Iron oxide as an effective sintering aid and a grain boundary scavenger for ceria-based electrolytes. Solid State Ionics 2004;167:203.
[15]H. Yahiro TO, K. Eguchi and H. Arai,. Electrical Properties and microstructure in the System Ceria-alkaline Earth Oxide. J. Mater. Sci.,23 1988:p1036.
[16]Mogensen M, Sammes NM, Tompsett GA. Physical, chemical and electrochemical properties of pure and doped ceria. Solid State Ionics 2000;129:63.
[17]Kharton VV, Figueiredo FM, Navarro L, Naumovich EN, Kovalevsky AV, Yaremchenko AA, Viskup AP, Carneiro A, Marques FMB, Frade JR. Ceria-based materials for solid oxide fuel cells. Journal of Materials Science 2001;36:1105.
[18]張凱翔. 異價離子共摻雜對氧化鈰之顯微結構與導電性質之影響. 國來台灣科技大學-機械工程系 2006.
[19]Schouler EJL, Kleitz M. Electrocatalysis and inductive effects at the gas,Pt/stabi;ized zirconia interface. Journal of the Electrochemical Society 1987;134:1045.
[20]Kawada T, Sakai N, Yokokawa H, Dokiya M. Electrical properties of transition-metal-doped YSZ. Solid State Ionics 1992;53-56:418.
[21]Lion SS, Worrell WL. Electrical properties of novel mixed-conducting oxides. Applied Physics A Solids and Surfaces 1989;49:25.
[22]Craciun R, Park S, Gorte RJ, Vohs JM, Wang C, Worrell WL. Novel method for preparing anode cermets for solid oxide fuel cells. Journal of the Electrochemical Society 1999;146:4019.
[23]Liu J. Direct-hydrocarbon solid oxide fuel cells. Progress in Chemistry 2006;18:1026.
[24]Paul DR, Robeson LM. Polymer nanotechnology: Nanocomposites. Polymer 2008.
[25]黃楠儒. 氣相成長碳纖維/碳管之研究. 國立成功大學-材料科學及工程學系碩士論文 1998.
[26]張淇芝. 基材製備對氣相成長碳纖維/管的影響. 國立成功大學-材料科學及工程學系碩士論文 2000.
[27]Reneker DH, Kataphinan W, Theron A, Zussman E, Yarin AL. Nanofiber garlands of polycaprolactone by electrospinning. Polymer 2002;43:6785.
[28]Huang Z-M, Zhang YZ, Kotaki M, Ramakrishna S. A review on polymer nanofibers by electrospinning and their applications in nanocomposites. Composites Science and Technology 2003;63:2223.
[29]Taylor G. Proc Roy Soc London A:p313、p453.
[30]Reneker、D.H、Fong、H. Polymer Nonofiber. Divison of Polymer Chemistry,Inc. American Chemical Society 2003:44.
[31]Doshi J, Reneker DH. Electrospinning process and applications of electrospun fibers. Journal of Electrostatics 1995;35:151.
[32]Kim K, Yu M, Zong X, Chiu J, Fang D, Seo YS, Hsiao BS, Chu B, Hadjiargyrou M. Control of degradation rate and hydrophilicity in electrospun non-woven poly(D,L-lactide) nanofiber scaffolds for biomedical applications. Biomaterials 2003;24:4977.
[33]Wang G, Huang X, Dudley M, Gouma PI, Yang X. Fabrication and characterization of molybdenum oxide nanofibers by electrospinning. Materials Research Society Symposium Proceedings, vol. 900, 2005. p.81.
[34]Wang G, Huang X, Yang X, Gouma PI, Dudley M. Electrospun tungsten oxide nanofibers: Fabrication and characterization. Materials Research Society Symposium Proceedings, vol. 915, 2006. p.155.
[35]Deitzel JM, Kleinmeyer J, Harris D, Tan NCB. Effect of processing variables on the morphology of electrospun nanofibers and textiles. Polymer 2001;42:261.
[36]Deitzel J, Sun Z, Herson D, Veleva A, Lamba N. Processing of biocidal electrospun nanofibers. vol. 52. Baltimore, MD, United States: Soc. for the Advancement of Material and Process Engineering, Covina, CA 91724-3748, United States, 2007. p.13.
[37]Demir MM, Yilgor I, Yilgor E, Erman B. Electrospinning of polyurethane fibers. Polymer 2002;43:3303.
[38]Pawlowski KJ, Belvin HL, Raney DL, Su J, Harrison JS, Siochi EJ. Electrospinning of a micro-air vehicle wing skin. Polymer 2003;44:1309.
[39]Mo X, Weber HJ. Electrospinning P(LLA-CL) nanofiber: A tubular scaffold fabrication with circumferential alignment. Macromolecular Symposia, vol. 217, 2004. p.413.
[40]A. B. US Patent[P] 1987:4 689 186.
[41]Lee JR, Park SJ, Seo MK, Park JM. Preparation and characterization of electrospun poly(ethylene oxide) (PEO) nanofibers-reinforced epoxy matrix composites. Materials Research Society Symposium Proceedings, vol. 851, 2005. p.217.
[42]Fennessey SF, Farris RJ. Fabrication of aligned and molecularly oriented electrospun polyacrylonitrile nanofibers and the mechanical behavior of their twisted yarns. Polymer 2004;45:4217.
[43]Azad AM, Matthews T, Swary J. Processing and characterization of electrospun Y2O3-stabilized ZrO2 (YSZ) and Gd2O3-doped CeO2 (GDC) nanofibers. Materials Science and Engineering B: Solid-State Materials for Advanced Technology 2005;123:252.
[44]Min B-M, Lee G, Kim SH, Nam YS, Lee TS, Park WH. Electrospinning of silk fibroin nanofibers and its effect on the adhesion and spreading of normal human keratinocytes and fibroblasts in vitro. Biomaterials, vol. 25 %W /cgi-bin/sciserv.pl?collection=journals&journal=01429612&issue=v25i7-8&article=1289_eosfnahkafiv: Elsevier Science, 2004. p.1289.
[45]王盈淇. 溫度效應對電紡絲製備高分子纖維之影響. 國立成功大學-化學工程學系碩士論文2006.
[46]Van Berkel FPF, van Heuveln FH, Huijsmans JPP. Characterization of solid oxide fuel cell electrodes by impedance spectroscopy and I-V characteristics. Solid State Ionics 1994;72:240.
[47]Adler SB. Factors governing oxygen reduction in solid oxide fuel cell cathodes. Chemical Reviews 2004;104:4791.
[48]Adler SB. Limitations of charge-transfer models for mixed-conducting oxygen electrodes. Solid State Ionics 2000;135:603.
[49]Fontaine ML, Larring Y, Norby T, Grande T, Bredesen R. Dense ceramic membranes based on ion conducting oxides. Annales de Chimie: Science des Materiaux 2007;32:197.
[50]J.R.Macdonald DRF. Theory of small-signal ac response of solids and liquids with recombining mobile charge. J.Chem.Phys. 1978;68:1614.
[51]呂家嘉. 固態氧化物燃料電池Ni含浸YSZ奈米纖維陽極之製備與特性量測. 國立台灣科技大學 2007.
[52]S.R.Stock BDCa. Elements of X-ray diffraction, 1978.
[53]Mendelson MI. Average grain size in polycrystalline ceramics. 1969;52:443.
[54]Palmqvist AEC, Zwinkels MFM, Zhang Y, Järås SG, Muhammed M. Reduction of sulfur dioxide by carbon monoxide over doped nanophase cerium oxides. Nanostructured Materials 1997;8:801.
[55]Machida M, Uto M, Kurogi D, Kijima T. Solid-gas interaction of nitrogen oxide absorbed on MnOx-CeO2: A DRIFTS study. Journal of Materials Chemistry 2001;11:900.
[56]Wang S, Inaba H, Tagawa H, Hashimoto T. Nonstoichiometry of Ce0.8Gd0.2O1.9-x. Journal of the Electrochemical Society 1997;144:4076.
[57]Mori T, Drennan J, Lee JH, Li JG, Ikegami T. Oxide ionic conductivity and microstructures of Sm- or La-doped CeO2-based systems. Solid State Ionics 2002;154-155:461.
[58]Zhang TS, Ma J, Kong LB, Chan SH, Kilner JA. Aging behavior and ionic conductivity of ceria-based ceramics: A comparative study. Solid State Ionics 2004;170:209.
[59]Transport-structure relations in fast ion and mixed conductors,proceedings of the 6th riso international symposium on metallurgy and materials science Proceedings of the Riso International Symposium on Metallurgy and Materials Science, 1985.
[60]Gabriele Balducci MSI, Jan Kasˇpar, Paolo Fornasiero, and, Graziani M. Reduction Process in CeO2-MO and CeO2-M2O3 Mixed
Oxides: A Computer Simulation Study. Chem. Mater. 2003;15:3781.
[61]Mori T, Drennan J, Wang Y, Lee JH, Li JG, Ikegami T. Electrolytic properties and nanostructural features in the La2O3-CeO2 system. Journal of the Electrochemical Society 2003;150:A665.
[62]Nakamura A, Wagner Jr JB. Defect structure,ionic conductivity, and diffusion in yttria stabilized zirconia and related oxide electrolytes with fluorite structure. Journal of the Electrochemical Society 1986;133:1542.
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
無相關期刊
 
系統版面圖檔 系統版面圖檔