보고서 내 다른 이미지

• 그림 SOFC 및 SOEC의 작동 원리
• 표 EU의 SOEC 프로그램
• 그림 (a) Nyquist and (b) Bode plots of the EIS data obtained from the symmetrical half cell (Ni-YSZ/YSZ/Ni-YSZ) at 700~850oC in H2-3% H2O environment under open circuit conditions. Equivalent circuit used for fitting is shown in (a).
• 표 Polarization resistance and capacitance at 700~850oC in H2-3% H2O under open circuit conditions obtained from equivalent circuit fitting.
• 그림 Temperature dependence of RHF and RMF at 700~850oC.
• 그림 Bode plot of the imaginary part of the impedance spectra measured at 750oC in H2-3% H2O and H2-35% H2O under open circuit condition.
• 그림 (a) Nyquist and (b) Bode plots of the impedance spectra measured at 750oC in H2-3% H2O under various polarization (+0.2V, 0V, and –0.2V).
• 그림 (a) Nyquist and (b) Bode plots of the impedance spectra measured at 750oC in H2-50% H2O under various polarization (+0.2V, 0V, and -0.2V).
• 그림 (a) Nyquist and (b) Bode plots of the impedance spectra measured in electrolysis mode (-0.2V) at 750oC with various H2O contents (3~60%), and (c) polarization resistance as a function of H2O content.
• 그림 EIS of LSM-YSZ electrode measured at 700-850oC in air and curve fitting results: (a) Nyquist plot and equivalent circuit model employed to fit the measured data, and (b) Bode plot. The high frequency intercept of the Nyquist plot was normalized to the value of zero for direct comparison.
• 그림 EIS measured at 800oC as a function of oxygen partial pressure and fitting results: (a) Nyquist plot and (b) Bode plot. The high frequency intercept of the Nyquist plot was normalized to the value of zero for direct comparison.
• 그림 Mid-frequency electrode resistance (RMF) as a function of (a) temperature and (b) oxygen partial pressure.
• 그림 EIS measured at 800oC and fixed oxygen partial pressure (pO2=0.05 atm) balanced with various inert gases (He, N2, and Ar): (a) Nyquist plot and (b) Bode plot. The high frequency intercept of the Nyquist plot was normalized to the value of zero for direct comparison.
• 그림 Low-frequency electrode resistances (RLF) with various inert gases (95% He, N2, and Ar) at fixed oxygen partial pressure (pO2=0.05).
• 그림 Cell voltage (LSM-YSZ anode potential vs. Pt reference electrode) as a function of time with the anodic current passage of 1.5 A cm-2 at 750oC in air.
• 그림 A series of EIS data obtained at time interval of 5~20 hours during the operation.
• 그림 Evolution of cell resistances with time obtained by fitting EIS data into the equivalent circuit model: (a) ROhmic and RMF, and (b) RLF.
• 그림 SEM image of the cross section of LSM-YSZ electrode after cathodic current passage (1.5 A cm-2) for 120 hours at 750oC in air.
• 그림 SEM image of the cross section of LSM-YSZ electrode after anodic current passage (1.5 A cm-2) for 120 hours at 750oC in air.
• 그림 SEM image of the interface area between LSM-YSZ electrode and YSZ electrolyte, showing extensive interdiffusion between two phases and intergranular fracture along YSZ grain boundaries after anodic current passage (1.5 A cm-2) for 120 hours at 750oC in air.
• 그림 SEM image and EDX line scan across the crack in the YSZ electrolyte. Scan was performed along the white line.
• 그림 SEM image of the LSM-YSZ electrode which delaminated from the YSZ electrolyte after anodic current passage (1.5 A cm-2) for 120 hours at 750oC in air.
• 그림 XRD pattern of the SSC-LSCF powder mixture, showing the crystallization behavior of SSC derived from the precursor solution and its chemical compatibility with LSCF at 800 oC. The powder mixture was prepared by dispersing LSCF powder in the SSC precursor solution and thermally treating it at 80 oC for 2 hours and 800 oC for 1 hour in air.
• 그림 SEM images of (a) the cross-section of the SORFC, (b) porous LSCF-GDC air electrode functional layer and (c) SSC nano-catalysts infiltrated into the LSCF-GDC air electrode.
• 그림 (a) I-V curves and corresponding power densities of the standard and SSC-infiltrated cells measured in SOFC mode at 750 oC with humidified hydrogen (3% H2O) on a hydrogen electrode and air on air electrode, and (b) I-V curves of the standard and SSC-infiltrated cells measured in SOFC and SOEC modes at 750 oC with humidified hydrogen (50% H2O) on a hydrogen electrode and an air on air electrode. VTN represents thermal neutral voltage for steam decomposition.
• 그림 Impedance spectra of the standard and SSC-infiltrated cells measured at 750 oC with (a) humidified hydrogen (3% H2O) on a hydrogen electrode and an air on air electrode at the OCV, (b) humidified hydrogen (3% H2O) on a hydrogen electrode and air on an air electrode at 0.7 V in SOFC mode, and (c) humidified hydrogen (50% H2O) on a hydrogen electrode and air on an air electrode at 1.2 V in SOEC mode.
• 그림 SEM images of (a) standard cell and (b) hydrogen electrode substrate.
• 그림 I-V curves and power densities of the standard cell in SOFC mode measured at 700~800oC with humidified hydrogen (3% H2O) as fuel and air as oxidant.
• 그림 I-V curves of the standard cell measured at 750oC with various compositions of H2-N2 mixture humidified with 3% H2O as fuel and air as oxidant.
• 표 Limiting current densities of the standard cell in SOFC operation under various fuel compositions at 750oC.
• 그림 Impedance spectra measured at 750oC with various compositions of H2-N2-H2O mixture as fuel and air as oxidant; (a) Nyquist and (b) Bode plots.
• 그림 Schematic diagram showing the variation of the partial pressures of the gas species in the hydrogen electrode during the operation of the SOFCs.
• 그림 Limiting current density of the hydrogen electrode substrate obtained from the cell measurements as a function of H2 partial pressure.
• 표 Transport and structural parameters of H2-H2O, H2-N2, and H2O-N2.
• 그림 I-V curves of the standard cell measured in SOEC mode at 750oC with various compositions of H2-H2O mixture at the hydrogen electrode and air at the air electrode.
• 그림 Schematic diagram showing the variation of the partial pressures of the gas species in the hydrogen electrode during the operation of the SOECs.
• 그림 SEM image of the hydrogen electrode substrate with increased porosity.
• 그림 I-V curves of the cells with 0 and 30 vol% PMMA pore forming agent in the hydrogen electrode substrate, measured at 750oC in SOFC and SOEC modes. SOFC curves were collected with humidified H2 (3% H2O) as fuel and air as oxidant. In SOEC tests, 33% H2O in H2 was supplied to the hydrogen electrode and air was circulated over the air electrode.
• 표 ASRs of cells with 0 and 30 vol% PMMA in the hydrogen electrode obtained in SOFC (at 0.7 V) and SOEC (at 1.29 V) modes.
• 그림 FIB-SEM 듀얼빔 장비의 구조
• 그림 높은 이온총 전류로 인해 거칠게 밀링된 단면 이미지
• 그림 내부의 pore에서 생길 수 있는 'curtain effect’
• 그림 slice된 면의 아래쪽에서 관찰되는 'shadow effect'
• 그림 LSC-GDC 반전지 모식도
• 그림 MM과 CM의 분말 제조 방법 모식도
• 그림 LSC-GDC SEM 이미지; 밝은 회색-LSC, 어두운 회색-GDC, 검은색- pore
• 그림 재구성된 LSC-GDC composite의 3차원 image
• 표 MM과 CM의 3차원 구조를 평가하는 정량적 결과
• 그림 SORFC (SOEC) 실험 장치의 개략적 구성
• 그림 SORFC 단전지 3차원 형상
• 그림 실험값과의 비교를 통한 모델 검증
• 그림 연료극에 인가되는 기체 조성에 따른 성능 변화
• 그림 (a) 수소가 포함된 기체 조성에 노출된 연료극, (b) 수소가 포함되지 않은 기체조성에 노출된 연료극 (20시간)
• 그림 작동 전압에 따른 온도 분포 변화: (a) 1.1 V, (b) 1.3 V, (c) 1.5 V, (d) 1.7 V
• 그림 온도에 따른 SORFC의 I-V curve의 변화 (700~900 ℃)
• 표 온도에 따른 전류밀도 및 OCV 변화 (1.3 V, H2O:H2=5:5, 26 Sccm)
• 그림 연료극에 인가하는 기체 조성에 따른 I-V curve의 변화 (H2O:H2=1:9~9:1)
• 표 연료극 기체 조성에 따른 전류밀도 변화 (1.3 V, 850 ℃, 26 Sccm)
• 그림 연료극에 인가하는 기체의 유량 변화에 따른 I-V curve 변화
• 표 연료극 기체 유량에 따른 전류밀도 변화 (1.3 V, 850 ℃, H2O:H2=5:5)
• 그림 공기극에 인가되는 기체의 조성에 따른 I-V curve의 변화
• 표 공기극 기체 조성에 따른 전류밀도 변화 (1.3 V, 850 ℃, 52 sccm)
• 그림 5x5 cm2 대면적 SOEC의 flow geometry에 따른 기체 분포도 변화
• 그림 (a) 10 cm ×10 cm unit cells and (b) the three-cell SORFC stack used in this study
• 그림 (a) Voltage of the cell with a LSM-based air electrode under SOEC operation at a constant current of -0.5 A cm-2 and (b) image of the surface of the cell after operation
• 그림 Voltage of the cell with a LSC-based air electrode under SOEC operation at constant current of -1.1 A cm-2
• 그림 Leakage rate obtained from the gasket-type glass-based sealants containing binary ceramic fibers
• 그림 (a) Current density-voltage-power density curves and (b) impedance spectra observed at open circuit conditions, all of which were obtained from the single cell analysis operating it in the fuel cell mode and at a temperature of 650~800°C
• 표 Performance of a single cell
• 그림 Current-voltage-power curves obtained from the three-cell SORFC stack operation in (a) the fuel cell mode using wet H2 (3% H2O) and (b) the electrolysis cell mode utilizing wet H2 (30% H2O)
• 그림 Regenerative operation (cycling between fuel cell and electrolysis cell modes) of the three-cell SORFC stack at 750°C using wet H2 (3% H2O) and 0.68 A cm-2 for the fuel cell mode and wet H2 (30% H2O) and -0.31 A cm-2 for the electrolysis cell mode
• 그림 1000-hours operation of the three-cell SORFC stack in the electrolysis cell mode using wet H2 (30% H2O) at 750°C and -0.31A cm-2
• 그림 SEM micrographs obtained after regenerative and 1000 hour long-term operations, showing (a) overall view of the cell which indicates that the fuel electrode and its interface with the electrolyte maintained good conditions, (b) crack formation within the electrolyte at the air electrode interface and (c) delamination of the air elect