Journal of the Korean Society for Precision Engineering

"전기화학적 임피던스 분광법"

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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

Abstract
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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.