학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2015. 2. 차석원.Thin-film solid oxide fuel cells supported on nano-porous anodic aluminum oxide substrates were fabricated by sequential sputtering methods. Cells were initially heated by three levels of heating rates (10 °Cmin-1, 30 °Cmin-1 and 50 °Cmin-1) from room temperature to the operating temperature of 450 °C. Grain growth of the electrolyte thin film was observed at the faster initial heating rateaverage grain sizes were measured by 13.09 nm (10 °Cmin-1), 25.92 nm (30 °Cmin-1) and 89.87 nm (50 °Cmin-1), respectively. Growth of Pt clusters of cathode was followed by grain growth of supporting electrolyte surface, resulting in the reduction of porosity and triple phase boundary. Cell performance was significantly decreased by slowed cathodic reaction kinetics originated from the grain growth of thin-film electrolyte surface and reduction of triple phase boundary. Faradaic area-specific resistance was almost doubled at the 50 °Cmin-1 of initial heating to the cell, compared to 10 °Cmin-1 heated cell. Annealing electrolyte before the deposition of cathode layer enhanced the crystallinity and interfacial stability with the cathode. As a result, increase of faradaic impedance by fast initial heating was significantly reduced.Abstract i
Contents ii
List of Tables iv
List of Figures iv
1. Introduction 1
1.1 Fuel cell 1
1.2 Thin-film solid oxide fuel cell 4
1.3 Objective of the research 7
2. Experimental 9
2.1 Cell fabrication 9
2.2 Electrochemical performance measurement 12
2.3 Annealing electrolyte 15
2.4 Further measurements and analyses 15
3. Result and discussion 16
3.1 Effect of initial heating rate on non-annealed cells 16
3.1.1 Performance variation of non-annealed cells 16
3.1.2 Surface morphology variation of non-annealed cells 21
3.2 Effect of initial heating rate on annealed-electrolyte cells 28
3.2.1 Annealing YSZ electrolyte 28
3.2.2 Performance variation of annealed-electrolyte cells 32
3.2.3 Surface morphology variation of annealed-electrolyte cells 37
4. Conclusion 41
Reference 42
국문 초록 45Maste
