本研究以靜電輔助超音波熱解法(Electrostatic assisted ultrasonic spray pyrolysis, EAUSP)、靜電噴塗法(Electrostatic spray deposition)與靜電紡絲法(Electro-spinning)製備鍶摻雜鈷酸釤(Sm0.5Sr0.5CoO3, SSC)陰極於氧化釓摻雜氧化鈰(Gd0.2Ce0.8O2, GDC)基材，以進行微結構與電化學性能之研究。
在EAUSP製程中，XRD結果顯示，鍛燒後的SSC氧化物膜具單相結晶結構，屬於鈣鈦礦結構(perovskite)，沒有第二相的產生。藉由SEM表面形貌觀察可知，改變外加電壓與鍍膜溫度對於鍍膜表面形貌有大幅度的影響。多孔柱狀具備層狀結構的SSC厚膜在400 oC的鍍膜溫度、10 kV的外加電壓與600秒的鍍膜時間下可製備得到，此種鍍膜型貌也是第一次被發表，並且藉由系統性地變化鍍膜參數，對鍍膜的成長機制加以討論。以EAUSP法得道之SSC陰極搭配GDC電解質進行交流阻抗分析(AC impedance measurement)結果顯示，以EAUSP法製備之SSC陰極相較於傳統製程陰極，在電化學性能表現上相當具有競爭力，在600 oC的操作溫度下，最低的介面阻抗(Area specific resistance, ASR)可達0.204 Ωcm2.
此外，ESD法亦應用於製備SSC薄膜於GDC基材上。XRD結果顯示，SSC薄膜在鍛燒後呈現鈣鈦礦結晶結構。ESD法所得之SSC薄膜表面形貌，受到鍍膜參數變化的影響甚大。因此，溶液流率、鍍膜溫度與鍍膜時間將系統性地變化，以得到鍍膜參數與鍍膜表面形貌的相關性，相關之鍍膜成長機制亦藉由鍍膜參數的變化進行討論。對以ESD法製備之SSC薄膜進行交流阻抗分析，結果顯示，在350 oC的鍍膜溫度與2.0 ml/hr的溶液流率條件下，所得到的多孔網狀具連續性的SSC薄膜具有最佳的電化學性能表現，在600 oC的操作溫度下，最低的ASR值可達0.09 Ωcm2，相較於其他以純SSC作為陰極之研究可知，此ASR值已是最佳表現。
在本研究中，SSC奈米線首次藉由靜電紡絲法得到，在鍛燒處理後，此奈米絲直徑介於40至90奈米，藉由超音波震盪後則可得到SSC奈米纖維。XRD與TEM結果顯示，SSC奈米纖維具多晶結構，其結晶屬於斜方(orthorhombic)鈣鈦礦結構。SSC奈米纖維藉由模版印刷法(Stencil printing method)於GDC基材上形成奈米纖維電極(nano-fiber electrode)，並進行交流阻抗分析。結果顯示，ASR值在600 oC的操作溫度下可達0.06 Ωcm2，此値為目前已發表之以純SSC作為單相陰極或SSC複合電解質所形成的複合陰極之最佳性能表示。

Deposition of Sm0.5Sr0.5CoO3 (SSC) films on Gd-doped ceria (GDC) substrates by electrostatic assisted ultrasonic spray pyrolysis (EAUSP) was demonstrated in this study. The XRD results indicate that crystalline phase with perovskite structure was obtained in the calcined films. SEM observations indicate that applied voltage and deposition temperature have profound effects on the film morphology in EAUSP method. Stronger applied voltage results in the smoother film while higher deposition temperature results in rougher film. A unique thick porous film with column structure is obtained for the first time by EAUSP method using a deposition temperature of 400 oC, an applied voltage of 10 kV and a deposition time of 600 seconds. The growth mechanism of the unique porous thick film is also discussed in this study. The area specific resistance (ASR) values of SSC cathode with this unique porous columnar structure are comparable to that obtained by conventional sample preparation routes. For example, an ASR value of 0.204 Ω•cm2 at 600 oC is obtained in this work.
Electrostatic spray deposition (ESD) method was also employed to deposit SSC films as cathode on GDC substrates in this study. Crystalline SSC with perovskite structure was obtained in the calcined films. Deposition parameters including deposition temperature, precursor flow rate and deposition time were systematically varied to obtain the SSC films with various morphologies. The best film structure for high electrochemical performance is a porous reticular structure obtained under a precursor solution flow rate of 2.0 ml/hr and a deposition temperature of 350 oC. The growth mechanism of this reticular structure is established based on the examination of film evolution in a series of films obtained with different deposition times. The minimum ASR value of the porous reticular SSC cathode fabricated by ESD is 0.09 Ω•cm2 at 600 oC.
SSC nano-wires were successfully synthesized by electro-spinning method. The diameter of calcined nano-wires ranges from 40 to 90 nm. The TEM results indicate that the calcined (800oC/2hr) SSC nano-wires are polycrystalline with an orthorhombic perovskite structure. SSC nano-fibers were then obtained from the SSC nano-wires through an ultrasonic vibration of 15 minutes. Electrodes of SSC nano-fiber on GDC substrate were then prepared by slurry printing method. The ASR values of SSC nano-fiber electrodes are extremely low and the minimum ASR value is 0.06 Ω•cm2 at 600 oC.

List of Figures……………………………………………………………………....…v
List of Tables………………………………………………………………………...xiv
摘要………………………………………………………………………….…….xvi
Abstract…………..………………………………………………………………xviii
Chapter 1 Introduction……………………………………………………………..….1
1.1 Fuel cell……………………………………………………………………..…1
1.2 Solid oxide fuel cell, SOFC……………………………………………………4
1.3 Mechanism of cathode reaction………………………………………………..7
1.4 The objective of this study………………………………………………….11
Chapter 2 Literature review…………………………………………………………..12
2.1 Spray pyrolysis……………………………………………………….………12
2.2 Electrostatic spray deposition (ESD) process……………………………….14
2.2.1 Atomization of precursor solution…………………………………….14
2.2.2 Aerosol transport……………………………………………………….18
2.2.3 Decomposition of droplets…………………………………………….18
2.3 Electrostatic assisted ultrasonic spray pyrolysis (EAUSP) process……….…23
2.3.1 Ultrasonic spray pyrolysis (USP) process……………………………...23
2.3.2 Electrostatic assisted ultra sonic spray pyrolysis (EAUSP)……………24
2.4 The electro-spinning process………………………………………………..27
2.5 The kinectics of electrode reaction in fuel cell………………………………31
2.5.1 The internal current loss………………………………………………32
2.5.2 The activation polarization……………………………………………..34
2.5.3 The concentration polarization…………………………………………36
2.5.4 The ohmic polarization…………………………………………………37
2.6 Electrochemical impedance spectroscopy (EIS)………………………..……38
2.6.1 The principles of EIS………………………………………………...…38
2.6.2 Equivalent circuit of a cell……………………………………………...40
2.6.3 Constant phase element, CPE…………………………………………..45
2.7 The crystal structure of Sm0.5Sr0.5CoO3……………………………………47
2.8 The conductivity of Sm0.5Sr0.5CoO3………………………………………….51
2.9 The performance of Sm0.5Sr0.5CoO3 cathode………………………….……..53
Chapter 3 Experimental procedure………………………………………………….55
3.1 Experimental procedure…………………………………………………….55
3.2 Procedure of EAUSP method…………………………………………….......57
3.2.1 The precursor solution preparation for EAUSP…………………….….58
3.2.2 EAUSP set-up..........................................................................................58
3.2.3 EAUSP method parameters………………………………………….…60
3.2.4 Characterizations of EAUSP film………………………………...……60
3.2.5 The density measurement of GDC pellet………………………………62
3.3 Procedure of ESD method………………………………………………...….64
3.3.1 The precursor solution preparation for ESD…………………………..65
3.3.2 ESD set-up………………………………………………………….…..67
3.3.3 Deposition of SSC films by ESD method………………………….…..68
3.3.4 Characterizations of ESD film………………………………………....69
3.4 Procedure of electro-spinning method……………………………………..73
3.4.1 The precursor solution preparation for electro-spinning……………..74
3.4.2 Electro-spinning set-up………………………………………….……..75
3.4.3 The electro-spinning parameter…………………………………..…….76
3.4.4 Characterizations of SSC nano-fibers………………………………..76
Chapter 4 Results…………………………………………………………….………79
4.1 The EAUSP results…………………………………………………………..79
4.1.1 The density measurement and observation of GDC substrate…………79
4.1.2 The TGA results of SSC precursor solution………………………….81
4.1.3 The XRD results of SSC films on GDC pellets…………………….….82
4.1.4 SEM morphology………………………………………………………85
4.1.5 AC impedance analysis……………………………………………….102
4.2 The ESD results……………………………………………………………..108
4.2.1 SSC on SDC substrate………………………………………………..108
4.2.1.1 XRD results……………………………………………….…….108
4.2.1.2 SEM results……………………………………………….…….110
4.2.1.2 AC impedance………………………………………………..…114
4.2.2 SSC on GDC substrate………………………………………………..116
4.2.2.1 XRD results……………………………………………………..116
4.2.2.2 SEM results……………………………………………………118
4.2.2.3 AC impedance………………………………………………..…130
4.3 Sm0.5Sr0.5CoO3 nano-fibers prepared by electro-spinning method………....136
4.3.1 XRD results……………………………………………………..…….136
4.3.2 SEM results…………………………………………………………138
4.3.3 TEM results…………………………………………………….……..142
4.3.4 AC impedance results…………………………………………..…….145
Chapter 5 Discussions…………………………………………………………….147
5.1 SSC deposited on GDC pellets by EAUSP method……………………..….147
5.1.1 XRD results……………………………………………………….…..147
5.1.2 SEM observations…………………………………………………….147
5.1.3 AC impedance results…………………………………………………155
5.2 SSC deposited on SDC or GDC pellets by ESD method……………...……158
5.2.1 XRD results……………………………………………………...……158
5.2.2 SEM observations………………………………………………….…158
5.2.3 AC impedance results……………………………………………...….164
5.3 SSC nano-fibers produced by electro-spinning…………………….……….167
Chapter 6 Conclusions………………………………………………………….…..170
6.1 EAUSP method………………………………………………………….….170
6.2 ESD method…………………………………………………………...……170
6.3 Electro-spinning method……………………………………………………171
Reference……………………………………………………………….......……….172

















List of Figures
Figure 1.1.1 The scheme of fuel cell operations……………………………….……2
Figure 1.2.1 The operating principle of SOFC………………………………...……4
Figure 1.2.2 The conductivities of common electrolytes [11]………………….…...6
Figure 1.3.1 The mechanism of ORR in SOFC cathode.[14]………………………7
Figure 1.3.2 The schematic diagram of a porous LSM electrode on a YSZ electrolyte.[14]…………………………………………………...……8
Figure 1.3.3 Schematic diagrams of (a) a single-phase mixed conductor and (b) a composite conductor used as SOFC cathode.[14]……………………..9
Figure 1.3.4 The schematic diagram of TPB. [14]……………………………...…10
Figure 2.2.1 The scheme of electrostatic spray……………………………………14
Figure 2.2.2 Various modes of electrostatic spray [34]………………………...….15
Figure 2.2.3 The scheme of Taylor cone…………………………………………..16
Figure 2.2.4 The growth mechanism proposed by Choy [40]………………..……19
Figure 2.2.5 The four types of film morphologies from Chen el al [35]…….…….20
Figure 2.2.6 The growth model of unique porous LiCoO2 films [41]………..……21
Figure 2.2.7 Sketch of film formation proposed by Beckel [43]…………………..22
Figure 2.3.1 The photographs of the fountain jets formation and breakup taken at different time, (a) t=0 s; (b) t=0.8 s; (c) t=1.3s; (d) t=2.8s [45], (e) The schematic diagram of the ultrasonic atomization……………….……24
Figure 2.3.2 The photographs of the contraction of mist flow. (a) Without applying extra high voltage, (b) Applying 10 kV high voltage. [50]………..…26
Figure 2.4.1 The schematic diagram of electro-spinning………………….…….28
Figure 2.4.2 The schematic of the trajectory of a jet in electrospinning process [61]…………………………………………………………………...29
Figure 2.4.2 Plots showing the dependence of nano-fiber diameter on various processing parameters: (A) concentration of PVP; (B) electrical field strength; (C) feeding rate of the ethanol solution; and (D) concentration of titanium isopropoxide [62]……………………………………….30
Figure 2.5.1 The diagram of a single cell with 1.2V theoretical voltage. [66]…….32
Figure 2.5.2 The schematic diagram of Tafel plots…………………………….….35
Figure 2.6.1 The Bode plot (a) and Nyquist plot (b) of impedance data presentation method………………………………………………………………..39
Figure 2.6.2 (a) The Randless equivalent circuit of an electrochemical cell.
(b) Subdivision of Zf into Rs, and Cs, or Rct and Zw…………………………….....40
Figure 2.6.3 Impedance plane of (a) low-frequency limit, (b) high-frequency limit and (c) the real system……………………………………………..…44
Figure 2.6.4 The equivalent circuit at high frequency limit……………………….45
Figure 2.6.5 The Nyquist plots of (a) only CPE and (b) a CPE parallel with a resistor……………………………………………………………..…46
Figure 2.7.1 A schematic diagram of ideal ABO3 Perovskite oxide. (a=b=c, α=β=γ=90O)……………………………………………………….….47
Figure 2.7.2 Crystal structure and oxygen transport in mixed conducting perovskite ABO3-δ. (a) Oxygen vacancies in ABO3-δ. (b) The hopping routes of oxygen vacancies between BO6 octahedrons [14]…………………...49
Figure 2.7.3 The linear thermal expansion coefficients of Sm0.5Sr0.5Co1-xFexO3 [78]…………………………………………………………………...50
Figure 2.8.1 SSC conductivity as a function of temperature [72]………......……..51
Figure 3.1.1 The experimental procedures of this study………………………….56
Figure 3.2.1 The experimental procedure for SSC films by EAUSP method…………………………………………………………..……57
Figure 3.2.2 The schematic diagram of EAUSP set-up……………………………59
Figure 3.2.3 The preparation of cross-sectional sample for SEM observation……61
Figure 3.2.4 The construction of symmetrical cells…………………………...…..62
Figure 3.3.1 The procedure of ESD method for SSC film deposition……….…….65
Figure 3.3.2 The schematic diagram of ESD set-up…………………………….…68
Figure 3.3.3 The construction of symmetrical cell with double-layer electrodes....71
Figure 3.3.4 The construction of symmetrical cell with SSC single-layer electrod.72
Figure 3.4.1 The procedure of electrospinning for SSC nano-wires and electrode.73
Figure 3.4.2 The schematic diagram of electrospinning set-up……………..……..75
Figure 3.4.3 The schematic diagram of SSC symmetrical cell with nano-fiber electrodes………………………………………………………….….78
Figure 4.1.1 The surface morphology of the GDC substrate……………………..80
Figure 4.1.2 The TGA analysis results of (a) weight loss and (b) differential data versus temperature………………………………………………...….81
Figure 4.1.3 The XRD pattern of SSC films on GDC substrates with a precursor concentration of 0.4 M, a deposition temperature of 400 oC, a deposition time of 180 seconds and different applied voltages (from 6 kV to 14 kV)……………………………………………………….…82
Figure 4.1.4 XRD patterns of SSC film on GDC substrates with a precursor concentration of 0.4 M, an applied voltage of 10 kV, a deposition time of 180 seconds and different deposition temperatures (from 350 to 540 oC)………………………………………………………………….....83
Figure 4.1.5 XRD patterns of SSC film on GDC substrate with a precursor concentration of 0.4 M, an applied voltage of 10 kV and a deposition temperature of 350 oC and different deposition times (from 5 to 300 seconds)………………………………………………………………84
Figure 4.1.6 The SSC film before calcinations……………………………………86
Figure 4.1.7 The SSC film after calcinations……………………………………...86
Figure 4.1.8 The EDS analysis results of calcined SSC films: (a) The analyzed spot for the EDS; (b) The EDS spectrum and the compositions of the film……………………………………………………………….…..87
Figure 4.1.9 Surface morphology of SSC films obtained under different applied voltages: (a) 6 kV; (b) 10 kV; (c) 12 kV; (d) 14 kV. The working distance, carrying gas flow rate, deposition temperature, deposition time and metal ion concentration are fixed at 3.0 cm, 1 l/min., 400 oC , 180 seconds and 0.4 M, respectively for all films……………………90
Figure 4.1.10 The cross-section micrographs of SSC films obtained under different applied voltages: (a) 6 kV; (b) 10 kV; (c) 12 kV; (d) 14 kV. The working distance, carrying gas flow rate, deposition temperature, deposition time and metal ion concentration are fixed at 3.0 cm, 1 l/min., 400 oC , 180 seconds and 0.4 M, respectively for all films…………………………………………………………………..91
Figure 4.1.11 Surface morphology of SSC films obtained under different deposition temperatures: (a) 350 oC; (b) 400 oC; (c) 450 oC; (d) 500 oC. The working distance, carrying gas flow rate, deposition time, applied voltage and metal ion concentration are fixed at 3.0 cm, 1 l/min., 180 seconds, 10 kV and 0.4 M, respectively for all films………………...94
Figure 4.1.12 The cross-section micrographs of SSC films obtained under different deposition temperatures: (a) 350 oC; (b) 400 oC; (c) 450 oC; (d) 500 oC. The other deposition parameters shown below are fixed during deposition. The working distance, carrying gas flow rate, deposition time, applied voltage and metal ion concentration are fixed at 3.0 cm, 1 l/min., 180 seconds, 10 kV and 0.4 M, respectively for all films……95
Figure 4.1.13 Surface morphology of SSC films obtained under different deposition times: (a) 30 seconds; (b) 120 seconds; (c) 180 seconds; (d) 300 seconds; (e) 600 seconds. The working distance, carrying gas flow rate, deposition temperature, applied voltage and metal ion concentration are fixed at 3.0 cm, 1 l/min., 400 oC , 10 kV and 0.4 M, respectively for all films……………………………………………………….…..98
Figure 4.1.14 The cross-section micrographs of SSC films obtained under different deposition times: (a) 30 seconds; (b) 120 seconds; (c) 180 seconds; (d) 300 seconds; (e) 600 seconds. The working distance, carrying gas flow rate, deposition temperature, applied voltage and metal ion concentration are fixed at 3.0 cm, 1 l/min., 400 oC, 10 kV and 0.4 M, respectively for all films…………………………………………….100
Figure 4.1.15 The surface and cross-section morphologies of the unique thick film. (a) The close-up micrograph of the column surface; (b) and (c) are the cross-section micrographs of columns; (d) The close-up of the cross-section of a column…………………………………………...101
Figure 4.1.16 The impedance spectra of samples of applied voltage series measured at 600 oC…………………………………………………………….102
Figure 4.1.17 The Arrhenius plot of ASR derived from impedance spectra as illustrated in Figure 4.1.16………………………………………….103
Figure 4.1.18 The impedance spectra of SSC/GDC/SSC cells with SSC films obtained at different deposition temperatures (measured temperature: 600 oC)………………………………………………………………104
Figure 4.1.19 The Arrhenius plot of ASR for samples of deposition temperature series………………………………………………………………105
Figure 4.1.20 The impedance spectra of SSC/GDC/SSC cells with SSC films obtained at different deposition temperature (measured at 700 oC)………………………………………………………………...…106
Figure 4.1.21 The Arrhenius plot of ASR for samples obtained with different deposition times……………………………………………………..107
Figure 4.2.1 The XRD patterns of SSC films obtained with different precursor flow rates on SDC substrates……………………………………….…….109
Figure 4.2.2 Surface morphology of SSC films obtained with different precursor flow rates: (a) 1.0 ml/hr for 300 minutes; (b) 2.0 ml/hr for 150 minutes; (c) 3.0 ml/hr for 100 minutes; (d) 5.0 ml/hr for 60 minutes. The working distance, deposition temperature and metal ion concentration are fixed at 3.0 cm, 300 oC and 0.01 M, respectively for all films…………………………………………………………………112
Figure 4.2.3 The cross-section morphology of, (a) the sprayed SSC film obtained with 5.0 ml/hr for 60 minutes on SDC pellet; (b) The stencil-printed SSC/SDC composite film on SDC pellet…………………….……..113
Figure 4.2.4 The impedance spectra of symmetrical cells with single- or double-layer SSC cathodes measured at 600 oC……………………114
Figure 4.2.5 The Arrhenius plot of electrode ASRs for symmetrical cells with single- or double-layer SSC cathodes on the SDC pellets……….…115
Figure 4.2.6 The XRD patterns of calcined SSC films on GDC deposited with a precursor concentration of 0.01 M, a deposition temperature of 350 oC, a deposition time of 60 minutes and different flow rates (from 0.5 to 4.0 ml/hr)………………………………………………………...….117
Figure 4.2.7 The XRD patterns of calcined SSC films on GDC deposited with a precursor concentration of 0.01 M, a precursor flow rate of 2.0 ml/hr, a deposition time of 60 minutes and different deposition temperatures (from 250 to 450 oC)……………………………………………….117
Figure 4.2.8 The XRD patterns of calcined SSC films on GDC deposited with a precursor concentration of 0.01 M, a precursor flow rate of 2.0 ml/hr, a deposition temperature of 350 oC and different deposition times (from 30 to 120 minutes………………………………………………...…118
Figure 4.2.9 Surface morphology of SSC films obtained under different flow rates: (a) 0.5 ml/hr for 240 minutes; (b) 1.0 ml/hr for 120 minutes; (c) 2.0 ml/hr for 60 minutes; (d) 4.0 ml/hr for 30 minutes; (e) 8.0 ml/hr for 15 minutes. The working distance, deposition temperature and metal ion concentration are fixed at 3.0 cm, 350 oC and 0.01 M, respectively for all films……………………………………………………………...120
Figure 4.2.10 Surface morphology of SSC films obtained at different deposition temperatures: (a) 250 oC; (b) 300 oC; (c) 350 oC; (d) 400 oC; (e) 500 oC. The working distance, precursor flow rate, deposition time and metal ion concentration are fixed at 3.0 cm, 2.0 ml/hr., 60 minutes and 0.01 M, respectively for all films……………………………………….123
Figure 4.2.11 Surface morphology of SSC films obtained with different deposition times: (a) 5; (b) 10; (c) 15; (d) 20; (e) 40; (f) 60; (g) 120 and (h) 180 minutes. The working distance, precursor flow rate, deposition temperature and metal ion concentration are fixed at 3.0 cm, 2.0 ml/hr., 350 oC and 0.01 M, respectively for all films…………………….127
Figure 4.2.12 The cross-section micrographs of SSC films obtained with different deposition times: (a) 5; (b) 10; (c) 20; (d) 40; (e) 120 and (f) 180 minutes. The working distance, precursor flow rate, deposition temperature and metal ion concentration are fixed at 3.0 cm, 2.0 ml/hr, 350 oC and 0.01 M, respectively for all films……………………..129
Figure 4.2.13 The impedance spectra at 600 oC of SSC/GDC/SSC cells with SSC cathodes obtained with different flow rates………………..………131
Figure 4.2.14 The Arrhenius plot of ASR for SSC cathodes obtained with different flow rates……………………………………………………………131
Figure 4.2.15 The impedance spectra at 600 oC of SSC/GDC/SSC cells with SSC cathodes obtained with different deposition temperature…………..133
Figure 4.2.16 The Arrhenius plot of ASR for samples of deposition temperature series……………………………………………………………..….133
Figure 4.2.17 The impedance spectra of SSC/GDC/SSC cells with SSC cathodes obtained with different deposition times (measured at 600 oC)………………………………………………………………..….135
Figure 4.2.18 The Arrhenius plot of ASR for SSC cathodes deposited with different deposition times…………………………………………………..…135
Figure 4.3.1 The XRD spectrum of (a) calcined SSC fibers; (b) calcined SSC fibers on GDC pellets……………………………………………………136
Figure 4.3.2 XRD patterns of SSC fibers and printed SSC fibers on GDC pellets, respectively. (a) Stencil printed SSC fibers on GDC pellets, (b) Only SSC fibers…………………………………………………………...137
Figure 4.3.3 The SEM micrographs of SSC belts obtained by electro-spinning: (a) As-spun SSC belt; (b) SSC belts after heat treatment of 500 oC/2hr; (c) SSC belts after calcination of 800 oC/2hr……………………..…….140
Figure 4.3.4 (a) The SEM micrographs of SSC nano-fibers after a calcination of 800 oC/2hr and an ultrasonic vibration of 15 minutes; (b) The SEM micrographs of SSC electrode made of SSC nano-fibers……….…..141
Figure 4.3.5 (a) The TEM bright field image of SSC nano-fibers; (b) The diffraction pattern of (a); (c) The SAD pattern from the grain circled by the dotted line in (a); (d) The simulated diffraction pattern of SSC……………143
Figure 4.3.6 (a) The TEM bright field image of SSC nano-fiber; (b) The high resolution image of the area circled by the dotted line in (a)……….144
Figure 4.3.7 The AC impedance spectra of SSC//GDC//SSC cell with SSC nano-fiber electrodes at the temperature range of 550-700oC…………………………………………………………146
Figure 4.3.8 The Arrhenius plots of ASR for (a) SSC nano-fiber cathode; (b) SSC cathode obtained by EAUSP………………………………………..146
Figure 5.1.1 Thermophorecsis effect at 3 mm distance to the substrate [96]….…148
Figure 5.1.2 The relationship between film thickness and deposition time for SSC films…………………………………………………………………152
Figure 5.1.3 The growth model of SSC films obtained by EAUSP method. (a) flight of droplets; (b) spreading of droplets; (c) preferential landing; (d) film growth…………………………………………………………….…154
Figure 5.1.4 Interfacial ASR values for SSC films obtained with a deposition temperature of 400°C and an applied voltage of 10 kV………….…157
Figure 5.2.1 The growth process of the reticular film. (a) spreading of droplets; (b) formation of ring-like hollows; (c) preferential landing effect; (d) growth of ridges and forming of reticular structure……………..….163
List of Tables
Table 1.1 Types of fuel cell [4]………………………………………………………..3
Table 2.1 The impedances of circuit elements……………………………………….41
Table 2.7.1 The cell parameters and the thermal expansion coefficients of Sm1-xSrxCoO3 [72]………………………………………………………..50
Table 2.9.1 The ASR values of Sm0.5Sr0.5CoO3 based cathode…………….………..54
Table 3.2.1 The chemicals and powder used in EAUSP………………………...…..58
Table 3.3.1 The chemicals and powder used in ESD………………………………66
Table 3.3.1 The chemicals of slurry used in stencil printing……………………….71
Table 3.4.1 The chemicals employed in precursor solution for electro-spinning method…………………………………………………………………....74
Table 3.4.2 The parameters of electro-spinning…………………………...…………76
Table 4.1.1 The densities of GDC pellets………………………………………..…..79
Table 4.1.2 The ASR values at 600 oC obtained from Figure 4.1.16……………….103
Table 4.1.3 The ASR for samples of deposition temperature series at 600 oC……105
Table 4.1.4 The ASR of samples of deposition time series measured at 600 oC…...107
Table 4.2.1 The deposition times employed in flow rate series………………….…108
Table 4.2.2 The ASR values obtained from Figure 4.2.4 at the measurement temperature of 600 oC………………………………………………...…115
Table 4.2.3 The deposition time employed in flow rate series…………………..…116
Table 4.2.4 The ASR values for samples of flow rate series at 600 oC………...…..130
Table 4.2.5 The ASR values at 600 oC obtained from Figure 4.2.15……………….132
Table 4.2.6 The ASR values of samples of deposition time series at 600 oC………134
Table 4.3.1 The comparison of the d-spacing of JCPDS #53-0112 and that measured from Figure 4.3.5c………………………………………………………142
Table 4.3.2 The ASR values of SSC nano-fiber cathodes at different temperatures………………………………………………………….…145
Table 5.3.1 Average and standard deviation of wire diameters: as-spun and calcined wires………………………………………………………………….....167

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