A Transformer model to predict the remaining useful life of a fuel cell, which has demonstrated superior performance in analyzing time series data. The dataset was created from long-term performance evaluation experiments conducted in rated power mode, with measurements taken every 10 hours. We preprocessed the raw data using a moving average, allocating 70% for training and 30% for evaluation. The model's performance, evaluated through MAE, MSE, and MAPE, was excellent. The fuel cell's critical voltage, defined as 94.5% of its initial voltage, was measured at 0.719 V. During the experimental run, the actual critical time was 106.6 hours, while the model predicted 106.8 hours, resulting in a 0.19% error. Since the predictions were based on data collected up to 93 hours, the estimated remaining life was 13.8 hours.
Solid Oxide Fuel Cells (SOFCs) are energy conversion devices known for their significantly higher power density compared to other fuel cell types. However, their high operating temperatures pose challenges related to thermal stability. To address this, research is focusing on Low-Temperature SOFCs (LT-SOFCs), which function at lower temperatures and exhibit enhanced electrochemical performance. While various electrode materials are utilized in SOFCs, platinum (Pt) stands out for its excellent electronic conductivity and catalytic activity. Unfortunately, at the operating temperatures of SOFCs, Pt tends to agglomerate, leading to a rapid reduction in the triple phase boundary (TPB) and a subsequent decline in electrochemical reactions. In this study, LT-SOFCs were fabricated with a Praseodymium Oxide (PrOx) capping layer applied to a porous Pt cathode using sputtering, with various thicknesses achieved by adjusting the deposition time. The electrochemical performance of the LT-SOFCs was measured at 500oC. Additionally, the degradation behavior of the LT-SOFCs was assessed by applying a constant voltage of 0.5 V for 48 hours. Scanning Electron Microscopy (SEM) analysis was also conducted on the PrOx capping layer thin films under the same operating conditions.
This study introduces a novel retainer ring design aimed at mitigating the edge effect during chemical mechanical planarization. The innovative design features an arch-shaped geometry that creates a bending effect, thereby reducing excessive pressure on the wafer's edge. A two-dimensional axisymmetric finite element model was developed, and simulation data were utilized to create a metamodel. Multi-objective optimization was conducted using an evolutionary algorithm, focusing on the normal contact stress on the wafer surface. Representative Pareto-optimal designs were analyzed to assess the distribution of normal contact stresses. The results demonstrated that the proposed design significantly reduced peak normal stresses and enhanced stress uniformity, especially at the wafer edge. This optimized retainer ring is anticipated to improve wafer edge quality and increase semiconductor yield.
The ionomer content in the catalyst layer is a crucial design factor that affects the performance of polymer electrolyte membrane fuel cells (PEMFCs). However, the optimal ionomer content can vary based on the surrounding humidity levels. This study systematically evaluated the influence of the ionomer-to-carbon (I/C) ratio (0.00, 0.55, and 0.91) on PEMFC performance under fully humidified (RH 100%) and low-humidity (RH 25%) conditions. Membrane-electrode assemblies (MEAs) were fabricated using a spray coating technique, and their electrochemical properties were analyzed through polarization curves and electrochemical impedance spectroscopy (EIS). Under RH 100%, the MEA with an I/C ratio of 0.55 achieved the highest peak power density of 519.8 mW/cm2, indicating a successful balance between proton conductivity and gas transport. Conversely, under RH 25%, the best performance of 203.9 mW/cm2 was observed at an I/C ratio of 0.91. This shift is attributed to improved water retention at higher ionomer content, which reduced membrane dehydration and lowered both ohmic and Faradaic resistances. These findings highlight the dual role of the ionomer in facilitating proton transport and managing water balance, emphasizing the necessity of optimizing the I/C ratio according to operating conditions for stable and high-performing PEMFC operation.
Degradation of proton exchange membrane fuel cells (PEMFCs) can be accelerated by impurities in the air. In maritime environments in particular, sodium chloride (NaCl) can reduce the performance of membrane electrode assembly (MEA) in PEMFCs. In this context, we experimentally analyzed effect of flow channel depth on PEMFCs humidified with a NaCl solution at the cathode side. The analysis was conducted in serpentine flow channels with different depths of 0.4, 0.8, and 1.6 mm. The initial performance of unit cells was compared to their performance after applying a constant current for 10 hours. Results showed that the degradation rate correlated positively with the flow-channel depth. Channel depths of 0.4 and 1.6 mm resulted in 2.4% and 7.3% decreases in the maximum power density, respectively. For the 1.6 mm channel depth, the activation loss after 10 hours was larger than the initial loss.
In this study, we developed and evaluated a simple device for removing ionic impurities that affect the performance of a polymer electrolyte membrane fuel cell (PEMFC) in a marine environment. In such environments, PEMFCs may experience performance degradation due to the presence of Na+ and Cl- in the air. To address this issue, the decontamination device was designed with both heating and cooling components. This device was positioned between a humidifier containing NaCl solution and a humidifier containing deionized water, both connected on the cathode side. The decontamination device effectively removed impurities (Na+ and Cl-) during experiments. As a result, the electrochemical performance of the fuel cell with the decontamination device improved compared to that of the fuel cell without it. Notably, the activation resistance and electrochemical surface area were significantly enhanced, and the ohmic resistance also improved when compared to the fuel cell without the decontamination device.
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Effects of NaCl Solution on Proton Exchange Membrane Fuel Cell with Serpentine Flow Channel of Different Depths Dong Kun Song, Ho Jun Yoo, Jung Soo Kim, Ki Won Hong, Do Young Jung, George Ilhwan Park, Gu Young Cho Journal of the Korean Society for Precision Engineering.2025; 42(5): 399. CrossRef
In this study, the effects of repetition of assembly and disassembly of polymer electrolyte membrane fuel cells on electrochemical performance were systematically investigated. Additionally, the effects of additional activation on polymer electrolyte membrane fuel cells were evaluated. All fuel cells were measured every three days. For the disassembled polymer electrolyte membrane fuel cells, membrane electrode assemblies were stored in a vacuum desiccator. For the maintained assembly, fuel cells were stored at room temperature. The performance and electrochemical characteristics of the fuel cell were analyzed by electrochemical impedance spectroscopy. As a result, the addition of activation to maintained assembly fuel cells showed the best performance among fuel cells with other assembly and activation conditions. Repetition of assembly and disassembly, as well as insufficient activation, caused degradation of the performance of fuel cells.
Polymer electrolyte membrane fuel cells (PEMFC) require activation to maximize their performance. Thus, an appropriate activation process is essential for the performance of the fuel cell. In this study, the performance of the fuel cell was investigated by changing the voltage range during the activation process. There were three voltage ranges: 0.3-0.9 V, 0.3-0.6 V, and 0.6-0.9 V. When the fuel cell was activated in the low voltage region, the highest performance was output. On the other hand, it showed the lowest performance at high voltage. The results suggest that it is advantageous to activate the fuel cell with a high current. On the other hand, if activation is performed while outputting at a low current, the generation of water and the electrochemical reaction are insufficient, resulting in a load on the fuel cell. Through this experiment, it was confirmed that the control method greatly affects fuel cell performance when activated.
In this study, the electrochemical characteristics of fuel cell were evaluated after applying a compressive load to the activation area of membrane electrode assembly (MEA) in polymer electrolyte membrane fuel cells. The effects of the pressed area under the compressive load were systematically investigated using polarization curves and electrochemical impedance spectroscopies (EIS) of the fuel cell. Interestingly, the performance of the fuel cell was improved as the pressed area of the MEA was increased from 25.2% to 100% of the active area. In addition, the increased pressed area led to a decrease in the ohmic resistance and the activation resistance of fuel cells.
Durability evaluations were conducted using polymer electrolyte membrane fuel cells in a marine environment. Deionised water and 3.5 wt% of NaCl solution were supplied to the cathode using an ultrasonic vibrator. Performance and electrochemical impedance spectroscopy of fuel cells were measured to evaluate the electrochemical behaviors. Additionally, long-term stability evaluations of PEMFCs were carried out at 0.65 V for 20 h. Following the experiments, scanning electron microscope analysis was conducted to confirm the presence of NaCl on membrane electrode assembly and micro porous layer of fuel cells.
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Effects of NaCl Solution on Proton Exchange Membrane Fuel Cell with Serpentine Flow Channel of Different Depths Dong Kun Song, Ho Jun Yoo, Jung Soo Kim, Ki Won Hong, Do Young Jung, George Ilhwan Park, Gu Young Cho Journal of the Korean Society for Precision Engineering.2025; 42(5): 399. CrossRef
Evaluation of Electrochemical Performance of PEMFCs with Decontamination Devices at Marine Environments Ye rim Kwon, Ho Jun Yoo, Byung Gyu Kang, Ki Won Hong, Sun Ki Kwon, Sanghoon Lee, Gu Young Cho Journal of the Korean Society for Precision Engineering.2025; 42(1): 57. CrossRef
A Study of Effects of the Repetition of Assembly and the Addition of Activation on Electrochemical Characteristics of PEMFCs Ji Woong Jeon, Gye Eun Jang, Young Jo Lee, Dong Kun Song, Ho Jun Yoo, Seung Hyeok Hong, Jung Soo Kim, Ye Rim Kwon, Da Hye Geum, Gu Young Cho Journal of the Korean Society for Precision Engineering.2023; 40(11): 867. CrossRef
A Study on Electrochemical Resistance Change through the Pressurization Process of MEA for PEMFC Ye Rim Kwon, Dong Kun Song, Ho Jun Yoo, Gye Eun Jang, Young Jo Lee, Jung Soo Kim, Ji Woong Jeon, Da hae Guem, Gu Young Cho Journal of the Korean Society for Precision Engineering.2023; 40(7): 539. CrossRef
Energy devices in modern society require high efficiency, carbon neutrality, and the capability of distributed power generation. A fuel cell is an energy conversion device, that satisfies all of these requirements. However, most fuel cells use hydrogen as a fuel, and more than half of hydrogen is currently produced through hydrocarbon reforming, resulting in significant energy loss. Additionally, the storage and supply of hydrogen require costly systems, and a large amount of energy is consumed during compression or liquidation processes. This paper develops a solid oxide fuel cell, that uses hydrocarbon directly as fuel to resolve this problem. A small amount of Ru is mixed with the Ni-based electrode, for the effective internal reforming of hydrocarbons. For rapid deposition of YSZ electrolytes, we developed a reactive sputtering process, using a DC power source. The developed thin-film solid oxide fuel cell, showed a performance of 76 mW/cm² at 500℃ using methane as fuel.
In this study, polymer electrolyte membrane fuel cells (PEMFCs) were humidified with NaCl solutions. NaCl solutions were provided to the cathode side of fuel cells by bubbling. De-Ionized water, 3.5 wt% NaCl solution, and 20 wt% NaCl solution were used to evaluate the effects of NaCl. Current density-voltage curves and electrochemical impedance spectroscopies (EIS) of fuel cells were measured. Additionally, the constant-voltage mode long-term stability of PEMFCs humidified with NaCl solution were investigated. Constant-voltage measurements and EIS results imply that the degradation of fuel cells is clearly related with the concentration of NaCl solutions.
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Effects of NaCl Solution on Proton Exchange Membrane Fuel Cell with Serpentine Flow Channel of Different Depths Dong Kun Song, Ho Jun Yoo, Jung Soo Kim, Ki Won Hong, Do Young Jung, George Ilhwan Park, Gu Young Cho Journal of the Korean Society for Precision Engineering.2025; 42(5): 399. CrossRef
Analysis of Electrochemical Behavior of PEMFC Humidified with NaCl Solution Mist Using an Ultrasonic Vibrator Ho Jun Yoo, Gye Eun Jang, Young Jo Lee, Dong Kun Song, Heeyun Lee, Gu Young Cho Journal of the Korean Society for Precision Engineering.2022; 39(12): 939. CrossRef
In this study, polymer bipolar plates for ultra-light polymer electrolyte membrane fuel cells (PEMFCs) were fabricated. Various methods for current collecting were applied to ensure electron conductivity of the polymer bipolar plates. Direct wire contact and Ag sputter process were applied. The Ag current collecting layer fabricated by the sputter process showed a well-covered and defectless surface. After preparations of bipolar plates, the effects of current collecting methods of bipolar plates on the electrochemical properties of PEMFCs were systematically investigated. The maximum power density of PEMFCs with the Ag current collecting of layered polymer bipolar plates decreased 37.39% because of increased ohmic resistance. However, the power/weight of PEMFCs with the Ag current collecting of layered polymer bipolar plates increased 27.23% because of the dramatically reduced weight (-50.63%) of bipolar plates compared to the graphite bipolar plates. We affirm that results in this report can provide meaningful insight for portable electrochemical energy devices.
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A Study on Electrochemical Resistance Change through the Pressurization Process of MEA for PEMFC Ye Rim Kwon, Dong Kun Song, Ho Jun Yoo, Gye Eun Jang, Young Jo Lee, Jung Soo Kim, Ji Woong Jeon, Da hae Guem, Gu Young Cho Journal of the Korean Society for Precision Engineering.2023; 40(7): 539. CrossRef
Thin film solid oxide fuel cells (TF-SOFCs) are considered to be a promising next generation energy conversion device. TFSOFCs have many advantages such as rapid turn-on and off, fuel flexibility, material flexibility, high power density and availability of compact system. Electrodes and electrolytes of TF-SOFCs are fabricated by thin film processes. In order to fabricate high performance TF-SOFCs, proper thin film processes have to be used due to the unique requirements of each part of the TF-SOFCs. This paper reviews the thin film deposition process for fabrication of TF-SOFCs and the advantages and disadvantages of physical and chemical vapor deposition processes. In addition, materials prepared through thin film processes and the performance results of TF-SOFCs are reviewed.
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Manipulating the grain boundary properties of BaCeO3-based ceramic materials through sintering additives introduction Gennady Vdovin, Anna Rudenko, Boris Antonov, Vacheslav Malkov, Anatoly Demin, Dmitry Medvedev Chimica Techno Acta.2019; 6(2): 38. CrossRef
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