Journal of the Korean Society for Precision Engineering

Performance Enhancement of Polymer Electrolyte Membrane Fuel Cells Using Porous Inserts in Flow Channels: Dongjin Kim, Jaejoong Kim, Geon Go, Suhyun Min, Seungwoo Lee, Taehyun Park; J. Korean Soc. Precis. Eng. 2026;43(7):787-793.
Published online July 1, 2026; DOI: https://doi.org/10.7736/JKSPE.026.00002

Abstract
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This study proposes a novel flow-field design strategy that incorporates porous inserts into the bipolar plate (BP) flow channels to address flooding and improve the performance of polymer electrolyte membrane fuel cells (PEMFCs). The BPs were fabricated by maintaining the traditional flow-field structure while varying the number and arrangement of melamine foam inserts, with the electrochemical performance changes analyzed comparatively. The findings revealed that the configuration featuring five porous inserts achieved the highest performance enhancement, with a peak power density increase of approximately 13.4% compared to the conventional cell. This improvement is attributed to localized pressure gradients created by the porous inserts, which facilitated transverse gas transport toward the gas diffusion layer and reduced flooding in the flow channels. However, excessive insertion resulted in increased flow resistance and mass transport limitations, leading to performance degradation. The study also confirmed the impact of insert arrangement on PEMFC performance. Overall, the introduction of porous inserts into BP flow channels, without the need for additional machining processes, offers an effective method for managing water and gas transport in PEMFCs, providing valuable insights for flow-field optimization and the development of high-performance fuel cell systems.

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Electrochemical Impedance Analyses of ePTFE-reinforced Polymer Electrolyte Membrane-based PEMFC with Varying Thickness and Relative Humidity: Gyutae Park, Subin Jeong, Youngjae Cho, Junseo Youn, Jiwon Baek, Jooyoung Lim, Dongjin Kim, Taehyun Park; J. Korean Soc. Precis. Eng. 2025;42(11):901-907.
Published online November 1, 2025; DOI: https://doi.org/10.7736/JKSPE.025.052

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The polymer electrolyte membrane fuel cell (PEMFC) generates electrical energy through electrochemical reactions and is a key technology for sustainable energy. The electrolyte membrane significantly affects performance under varying conditions. This study examines the impact of membrane thickness and relative humidity (RH) on PEMFC performance using j-V curves and electrochemical impedance spectroscopy (EIS). Experiments were conducted with membrane thicknesses of 30, 15, and 5 μm under RH conditions of 100%-100% and 100%-0%. Under RH 100%-100%, performance improved as the membrane thickness decreased, with values of 954, 1050, and 1235 mW/cm² for the 30, 15, and 5 μm membranes, respectively. The 5 μm membrane demonstrated a 23% performance improvement over the 30 μm membrane. Under RH 100%-0%, performances were 422, 642, and 852 mW/cm², with degradation rates of 55.8%, 39.0%, and 32.1%. The 5 μm membrane exhibited the lowest degradation rate, indicating superior performance under low humidity. These results suggest that thinner membranes generally enhance performance and maintain efficiency even in dry conditions.

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Additional Ionomer-coated Layer for Self-humidifying Polymer Electrolyte Membrane Fuel Cells: Gyutae Park, Dongjin Kim, Junseo Youn, Junghyun Park, Hyoun-Myoung Oh, Taehyun Park; J. Korean Soc. Precis. Eng. 2023;40(12):997-1001.
Published online December 1, 2023; DOI: https://doi.org/10.7736/JKSPE.023.097

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In this study, we aim to develop a self-humidifying polymer electrolyte membrane fuel cell (PEMFC) by depositing platinum (Pt) on a membrane using sputtering. After we coated it with a Nafion^® ionomer solution. This is considered a solution that can prevent membrane degradation in low humidity conditions. By introducing this self-humidifying concept, we can expect improved performance compared to conventional PEMFCs. By managing the water content of Nafion^®, we aim to improve both the stability and performance of the PEMFCs. This research contributes to the development of more efficient and reliable PEMFC systems, showing promise for advances in this field.

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Evaluation of Frictional Characteristic of Galvannealed sheet steel with different annealing temperatures at Lower Normal Loads: Jungmin Lee, Seongjin Jeon, Donghwan Kim, Byungmin Kim, Dongjin Kim, Sungho Park; J. Korean Soc. Precis. Eng. 2006;23(4):109-115.
Published online April 1, 2006

Abstract
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This paper is designed to estimate friction and powdering characteristic of coating layer on galvannealed sheet steel with different annealing temperature, which is 465, 505, 515 and 540℃. Estimations of powdering and friction were done using a 60ㆍbending test and one side friction test, respectively. In order to obviously understand the effect of coatings on friction cross-section of coatings before and after friction test was also observed by SEM. The results show that powdering of coatings is increased with increasing of annealing temperature and that friction characteristic greatly depends on powdering which leads to increase of real contact area between tools and coatings.