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공극률이 변하는 다공성 유로를 적용한 고분자 전해질막 연료전지의 성능 향상에 관한 연구
강동균(DongGyun Kang),이동근(DongKeun Lee),김민수(Minsoo Kim) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
In this study, several different porous flow fields with different porosity gradients are introduced and used as flow distributors in the polymer electrolyte membrane fuel cell. To be more specific, the effect of the porosity gradient direction in the porous flow field is studied in this research. We evaluate the performance of the fuel cell with different porosity gradient directions in different porous flow fields by scrutinizing several polarization curves and power curves. In additions, we discuss the electrochemical losses of fuel cells using different porous flow fields by conducting the electrochemical impedance spectroscopy test. Finally, we conclude that the proper porosity gradient direction in the porous flow field improves the performance of the fuel cell compared with the fuel cell with porous flow field without porosity gradient.
다중 공기 공급을 적용한 고분자 전해질막 연료전지의 성능 향상에 관한 연구
강동균(DongGyun Kang),신동규(Dongkyu Shin),김민수(Minsoo Kim) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
It is significant to reduce concentration losses of polymer electrolyte membrane fuel cell (PEMFC) in high current density range. Therefore, many researchers have studied on the oxygen depletion in the flow field of cathode side and removing produced water, which has effects on the concentration losses. One of the solutions to have lower oxygen depletion along the flow channel is having higher oxygen concentration in the catalyst layer along the flow path in the cathode side. In this study, we used the serpentine flow field with dual air inlets, instead of a single air inlet in the cathode side. And we conducted the experiments for the performance comparison between the fuel cell with a single air inlet and the fuel cell with dual air inlets not only using 100% humidified air, but using dehumidified air. Furthermore based on the experimental results, we did numerical analysis for studying the factors and reasons of performance improvement of fuel cell with dual air inlets. Finally, we verified that the fuel cell with dual air inlets has relatively higher oxygen concentration in the catalyst layer along the flow path than the fuel cell with a single air inlet.
오일 양이 최소화된 물/오일 에멀젼을 통한 구형 마이크로 크기 실리카 합성
표은지 ( Eunji Pyo ),차연아 ( Yeona Cha ),강동균 ( Donggyun Kang ),권기영 ( Ki-young Kwon ) 한국공업화학회 2020 공업화학 Vol.31 No.6
W/O 에멀젼을 통해 구형의 실리카를 합성하는데 있어서 오일의 양을 최소화하는 연구를 수행하였다. 물유리 283 g에 오일로서 헥산을 최소한으로 20~60 mL 사용하여 구형의 실리카가 합성됨을 확인하였다. 실리카의 크기는 오일의 양에 의존하였으며, 오일의 양이 증가함에 따라서 실리카 입자의 크기가 증가하는 것을 확인하였다. 합성된 구형 실리카의 비표면적을 BET법을 통해 측정해본 결과 186~230 m<sup>2</sup>/g 값임을 확인하였다. XRF 분석으로부터 90% 이상이 SiO<sub>2</sub>임을 확인하였으며, 물유리 사용으로 인한 나트륨이 3.27~4.5 wt. %의 불순물로 함유되어 있었다. 본 연구에서 제조한구형의 실리카는 Si의 전구체를 공업용 규산나트륨 용액을 사용함과 더불어 최소한의 헥산과 비이온계면활성제를 통하여 만들어졌기 때문에 대량 합성 및 상업화에 최적화되어 있는 조건이라고 판단된다. We prepared spherical silica by minimizing the amount of oil through water/oil (W/O) emulsion. The spherical silica was successfully synthesized by using 20 to 60 mL of hexane as an oil for 283 g of water glass. The size of silica was dependent on the amount of oil where the size of silica particles increased as the amount of oil increased. The specific surface areas of samples measured using the BET method were 186 to 230 m<sup>2</sup>/g. X-ray fluorescence (XRF) analysis results showed that the SiO<sub>2</sub> content was more than 90% while sodium was 3.27~4.5 wt. %. The spherical silica prepared in this study could be optimized for mass synthesis and commercialization because the industrial sodium silicate solution was used as a precursor of Si as well as the minimum amounts of hexane and nonionic surfactant were employed.