https://scholar.gist.ac.kr/handle/local/7966 2026-08-07T00:13:09Z 2026-08-07T00:13:09Z 조영훈 https://scholar.gist.ac.kr/handle/local/19904 2025-06-30T12:13:26Z 2024-12-31T15:00:00Z

Title: 직접 암모니아 연료전지의 Perovskite 구조 기반 Anode의 B-site 화학양론 제어를 통한 성능 개선 연구 Author(s): 조영훈 Abstract: Ammonia has high energy density and the advantage of utilizing existing infrastructure, making it increasingly significant as a direct fuel for energy production in solid oxide fuel cell (SOFC). However, ammonia-fueled SOFC have a lower power density compared to hydrogen fuel cells. To address this issue, this study investigates Sr2Fe1.6M0.5O6-δ, an electrode material based on Sr2Fe1.5M0.5O6-δ with high conductivity and stability under reducing environments, by further increasing the Fe content. The structural stability and the formation of Fe nanoparticles on the electrode surface were confirmed through XRD, SEM, and TEM analyses. The electrochemical performance and catalytic properties of the fuel cells were evaluated. As the Fe content increased, more Fe nanoparticles were formed under reducing conditions, enhancing both electrochemical and catalytic performance. Notably, the electrochemical performance of the DA-SOFC increased by approximately 2.4 times, achieving performance comparable to fuel-electrode-supported DA-SOFCs. In conclusion, this study demonstrates a viable solution to overcome the performance limitations of oxide electrode as anode.

2024-12-31T15:00:00Z Heeji Lee https://scholar.gist.ac.kr/handle/local/33864 2026-03-03T05:21:49Z 2025-12-31T15:00:00Z

Title: 전이금속 기반 촉매 활성 집전체를 이용한 메탄 연료 고체산화물연료전지의 성능 및 장기 안정성 향상 연구 Author(s): Heeji Lee Abstract: Solid oxide fuel cells (SOFCs) are high-efficiency energy conversion devices that directly convert chemical fuels into electricity. Owing to their high operating temperature of 600–1000 ℃, SOFCs can internally reform hydrocarbon fuels such as methane without requiring an external reformer. However, when operating with methane fuel, carbon generated through the thermal decomposition reaction (CH4 → C + 2H2) can accumulate on the anode surface, causing performance degradation and shortening cell lifetime. Steam methane reforming (SMR) is an effective strategy to mitigate carbon deposition, as sufficient steam supply promotes the oxidation of deposited carbon. Conventional Ni-based anode supports and Ni foam current collectors exhibit excellent performance under hydrogen but remain highly susceptible to carbon formation when exposed to methane. In this study, a Cu-Ni transition- metal alloy was designed and fabricated as a catalyst-functionalized current collector to simultaneously enhance SMR activity and suppress carbon deposition. Cu inhibits carbon-carbon bond formation on Ni surfaces, thereby reducing coking, while Ni maintains reforming activity by facilitating C-H bond activation during methane conversion. This work aims to improve the electrochemical performance and long-term stability of methane-fueled SOFCs through the application of the Cu-Ni-based catalyst- current collector structure. MS/EN 20241089 Heeji Lee (이희지). Performance and Long-Term Stability Enhancement of Methane-Fueled Solid Oxide Fuel Cells using Transition-Metal-Based Catalyst–Active Current Collectors (전이금속 기반 촉매 활성 집전체를 이용한 메탄 연료 고체산화물연료전지의 성능 및 장기 안정성 향상 연 구). College of Engineering. Department of Environment and Energy Engineering. 2025. 84 p. Advisor Prof. Jong Hoon Joo

2025-12-31T15:00:00Z HyunWoo Choi https://scholar.gist.ac.kr/handle/local/31979 2025-09-08T02:51:19Z 2024-12-31T15:00:00Z

Title: 연료극 지지형 고체산화물 셀의 제조과정에 따른 전기화학적 성능 최적화 및 열화 메커니즘 분석 Author(s): HyunWoo Choi Abstract: Solid Oxide Cells (SOCs) are promising high-temperature electrochemical devices that offer high energy conversion efficiency and operate without the need for noble metal catalysts, enabling cost-effective and environmentally friendly energy systems. Hydrogen, as a clean fuel, can be utilized to generate electricity in SOCs. Yttria-Stabilized Zirconia (YSZ) is commonly used as an oxygen ion-conducting electrolyte, and Ni-based cermets are typically employed as fuel electrodes. SOCs utilizing a Ni cermet-supported anode allow for the application of thin electrolytes, thereby significantly reducing ohmic resistance and enhancing power density. However, when ZrO₂-based electrolytes are used, the interdiffusion of La and Sr from the cathode can result in the formation of secondary phases such as LaZrO₃, SrZrO₃, and La₂Zr₂O₇, which degrade ionic conductivity and increase interfacial resistance. To mitigate such reactions, a barrier layer such as Gd₂O₃-doped CeO₂ (GDC) is typically introduced between the electrolyte and cathode, requiring high-temperature co-sintering (1250°C– 1450°C). However, the co-sintering process may also induce undesired reactions between GDC and YSZ, forming secondary phases such as Gd₂Zr₂O₇, which deteriorate electrochemical performance. Additionally, Ni diffusion from the anode into the YSZ electrolyte can lead to phase instability and degradation in conductivity during long- term operation. Despite these challenges, there is limited research addressing processing strategies to suppress interfacial reactions during co-sintering, as well as the impact of Ni diffusion on the ionic conductivity and structural stability of YSZ electrolytes. Therefore, this study aims to investigate the effects of post-sintering treatments at reduced temperatures—enabled through compositional modifications—on the suppression of secondary phase formation and to evaluate the electrochemical performance and degradation mechanisms resulting from Ni diffusion in YSZ-based electrolytes.

2024-12-31T15:00:00Z 이동열 https://scholar.gist.ac.kr/handle/local/19902 2025-06-30T12:13:23Z 2024-12-31T15:00:00Z

Title: 비백금 음이온 교환막 수전해를 위한 철 도핑 활용 니 켈-몰리브데넘 합금 촉매의 활성점 제어 Author(s): 이동열 Abstract: Developing advanced catalysts for the hydrogen evolution reaction in alkaline media remains a significant hurdle for the broader adoption of anion exchange membrane water electrolyzers. This study presents the synthesis of an Fe-doped Ni4Mo/MoOx catalyst through a synergistic approach involving hydrothermal and thermal reduction processes. Material characterization and electron structure analysis underscored the pivotal role of Fe, and its addition notably promoted the formation of the Ni4Mo phase, which was identified as active site of the catalyst. Further insights from density functional theory calculations revealed that Fe doping enhanced the desorption energy necessary for the H2 recombination step within the Ni4Mo phase, bolstering both the intrinsic and extrinsic activities. This enhancement propelled the NiMoFe catalyst to outperform conventional NiMo catalysts in both aqueous model system and membrane electrode assembly experiment. Notably, an anion exchange membrane water electrolysis configured with the NiMoFe catalyst at the cathode demonstrated remarkable performance, reaching a cell voltage of 1.63 V at a current density of 1 A cm-2, and preserving over 98% of its initial voltage at 0.5 A cm-2, demonstrating its potential for commercial applications.

2024-12-31T15:00:00Z