Search Results (92)

The geometric design of flow channels in bipolar plates is one of the critical features of proton exchange membrane fuel cells (PEMFCs), as it determines the power output of the fuel cell and has a significant impact on its performance and durability. The function of the bipolar plate is to guide the transfer of reactant gases to the gas diffusion layer and catalytic layer inside the PEMFC, while removing unreacted gases and gas–liquid byproducts. Therefore, the design of the bipolar plate flow channel is directly related to the water and thermal management of the PEMFC. In order to improve the comprehensive performance of PEMFCs and ensure their safe and stable operation, it is necessary to design the flow channels in bipolar plates rationally and effectively. This study addresses the limitations of existing bipolar plate flow channels by proposing a new coupling of serpentine and radial channels. The distribution of oxygen, water concentrations, and temperature inside the channel is simulated using the multi-physics simulation software COMSOL Multiphysics 6.0. The performance of this novel design is compared with conventional flow channels, with a particular focus on the pressure drop and current density to evaluate changes in the output performance of the PEMFC. The results show that the maximum current density of this novel design is increased by 67.36% and 10.43% compared to straight channel and single serpentine channels, respectively. The main contribution of this research is the innovative design of a new coupling of serpentine and radial channels in bipolar plates, which improves the overall performance of the PEMFC. This study provides theoretical support for the design of bipolar plate flow channels in PEMFCs and holds significant importance for the green development of energy. Full article

Ti/a-C:Cr multilayer films were deposited on 316L stainless steel (SS316L) substrates using medium-frequency alternating current magnetron sputtering, with a single-layer a-C:Cr film also prepared on a titanium substrate. The influence of sputtering pressure on the film’s structure and properties was systematically investigated. Film morphology and microstructure were analyzed via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). At a pressure of 1.4 MPa, the interfacial contact resistance (ICR) of SS316L bipolar plates (BPPs) coated with the films reached as low as 3.30 mΩ·cm², while that of titanium BPPs was 2.90 mΩ·cm². Under simulated proton exchange membrane fuel cell (PEMFC) cathode conditions (70 °C, 0.6 V vs. SCE, 0.5 M H₂SO₄, 5 ppm HF solution), the corrosion current density, Icorr, reached optimal values of 0.69 μA·cm⁻² for SS316L and 0.62 μA·cm⁻² for titanium. These results demonstrate that parameter optimization enables SS316L BPPs to functionally replace titanium counterparts, offering significant cost reductions for metal BPPs and accelerating the commercialization of PEMFC technology. Full article

This study investigates the effects of anode and cathode inlet flow rates (ṁ) on the power performance of bipolar plates in a polymer electrolyte membrane fuel cell (PEMFC). The primary objective is to derive optimal flow rate conditions by comparatively analyzing concentration loss in the I−V curve and crossover phenomena at the anode, thereby establishing flow rates that prevent reactant depletion and water flooding. A single-cell computational model was constructed by assembling a commercial bipolar plate with a gas diffusion layer (GDL), catalyst layer (CL), and proton exchange membrane (PEM). The model simulates current density generated by electrochemical oxidation-reduction reactions. Hydrogen and oxygen were supplied at a 1:3 ratio under five proportional flow rate conditions: hydrogen (${\dot{m}}_{H_2}$ = 0.76–3.77 LPM) and oxygen (${\dot{m}}_{O_2}$ = 2.39–11.94 LPM). The Butler–Volmer equation was employed to model voltage drop due to overpotential, while numerical simulations incorporated contact resistivity, surface permeability, and porous media properties. Simulation results demonstrated a 24.40% increase in current density when raising ${\dot{m}}_{H_2}$ from 2.26 to 3.02 LPM and ${\dot{m}}_{O_2}$ from 7.17 to 9.56 LPM. Further increases to ${\dot{m}}_{H_2}$ = 3.77 LPM and ${\dot{m}}_{O_2}$ = 11.94 LPM yielded a 10.20% improvement, indicating that performance enhancements diminish beyond a critical threshold. Conversely, lower flow rates (${\dot{m}}_{H_2}$ = 0.76 and 1.5 LPM, ${\dot{m}}_{O_2}$ = 2.39 and 4.67 LPM) induced hydrogen-depleted regions, triggering crossover phenomena that exacerbated anode contamination and localized flooding. Full article

The development of bipolar plate materials with enhanced corrosion resistance and surface conductivity is critical for the commercial application of proton exchange membrane fuel cells (PEMFCs). The corrosion behavior and surface conductivity of electrochemically nitrided 446 stainless steel with and without the pretreatment of Cr-enrichment were investigated in the simulated PEMFC anode and cathode environments (i.e., 0.5 mol L⁻¹ H₂SO₄ + 2 ppm HF solution bubbled with hydrogen or air at 80 °C) using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma–mass spectrometry (ICP-MS), and electrochemical measurement techniques. Extending the nitriding time from 5 to 30 min enhances the surface conductivity but reduces the corrosion resistance. After the pretreatment and 30 min of nitridation, a thin film formed on the specimen surface, which mainly consists of Cr-nitrides and -oxides with atomic fractions of 0.42 and 0.37, respectively. The Cr-enriched and nitrided specimen shows spontaneous passivation in both the simulated cathode and anode environments and higher corrosion potentials, lower passive current densities, and larger polarization resistances in comparison with the directly nitrided specimens. Its stable current densities are about 0.26 and −0.39 μA cm⁻² after 5 h of polarization tests at 0.6 V_SCE in the cathode environment and at −0.1 V_SCE in the anode environment, respectively. Its contact resistance is about 5.0 mΩ cm² under 1.4 MPa, which is close to that of the specimen directly nitrided for 120 min and slightly decreases after the potentiostatic polarization tests. These results indicate that Cr-rich pretreatment improves not only the corrosion resistance and surface conductivity of nitrided specimens but also the efficiency of electrochemical nitridation. Full article

Aluminium is an attractive material for proton-exchange-membrane fuel cell bipolar plates as it has a much lower density than steel and is easier to form than both steel and graphite. This work focused on the development of amorphous carbon films deposited using closed-field unbalanced magnetron sputtering (CFUBMS) in order to improve the corrosion resistance of aluminium bipolar plates and to enhance fuel cell performance and durability. Chromium and tungsten adhesion layers were used for the coatings. It was possible to achieve good electrical conductivity and high electrochemical corrosion resistance up to 70 °C on polished Aluminium alloy 6082 by tuning the deposition parameters. Coatings with a tungsten adhesion layer showed better corrosion resistance than those with a chromium adhesion layer. In situ, accelerated stress testing of single cells was performed using uncoated and coated Al6082 bipolar plates. Both coatings resulted in improved fuel cell performance compared to uncoated aluminium when used on the cathode side of the fuel cell. Full article

The insufficient corrosion resistance and high interfacial contact resistance (ICR) of 316L stainless steel (316L SS) severely limit its application as bipolar plates (BPs) in proton exchange membrane fuel cells (PEMFCs). In this study, a graphite/carbon black/PVDF composite coating was first developed by hot rolling on the surface of 316L SS to enhance both corrosion resistance and conductivity. By incorporating 5 wt% polyaniline (PANI) as a corrosion inhibitor, the optimized RP5 coating exhibited further improvements in corrosion resistance. The potentiodynamic polarization tests revealed that the RP5 coating achieved a corrosion current density of 0.977 μA·cm⁻², representing a two-orders of magnitude reduction compared to bare 316L SS (34.1 μA·cm⁻²). The coating also exhibits a satisfactory interfacial contact resistance (ICR) of 8.20 mΩ·cm² at 1.5 MPa, meeting the U.S. Department of Energy (DOE) 2025 targets (<10 mΩ·cm²). Additionally, the RP5 coating exhibited superior hydrophobicity with a water contact angle of 96.5°, which is advantageous for water management within PEMFCs. The results confirm that the RP5 coating achieves an optimal balance between high conductivity, excellent corrosion resistance, and improved hydrophobicity, making it a promising solution for advancing PEMFC bipolar plates’ performance. Full article

Additive manufacturing (AM) technologies have witnessed remarkable advancements, offering opportunities to produce complex components across various industries. This paper explores the potential of AM for fabricating bipolar plates (BPPs) in fuel cell or electrolysis cell applications. BPPs play a critical role in the performance and efficiency of such cells, and conventional manufacturing methods often face limitations, particularly concerning the complexity and customization of geometries. The focus here lies in two specific AM methods: the laser powder bed fusion of metals (PBF-LB/M) and material extrusion of metals (MEX/M). PBF-LB/M, tailored for high-performance applications, enables the creation of highly complex geometries, albeit at increased costs. On the other hand, MEX/M excels in rapid prototyping, facilitating the swift production of diverse geometries for real-world testing. This approach can facilitate the evaluation of geometries suitable for mass production via sinter-based manufacturing processes. The geometric deviations of different BPPs were identified by evaluating 3D scans. The PBF-LB/M method is more suitable for small features, while the MEX/M method has lower deviations for geometrically less complex BPPs. Through this investigation, the limits of the capabilities of these AM methods became clear, knowledge that can potentially enhance the design and production of BPPs, revolutionizing the energy conversion and storage landscape and contributing to the design of additive manufacturing technologies. Full article

The broad use of (stainless steel) SS 316 L bipolar plates (BPs) in proton exchange membrane fuel cells relies (PEMFC) on high conductivity and corrosion resistance. To enhance the properties of stainless steel, this study applies ion implantation and heat treatment to form a non-homogeneous modified layer on SS 316 L. The injection of C and Mo ions on the SS 316 L surface caused irradiation damage, producing holes. But with the heat treatment of the ion-implanted samples, the irradiation-damaged surface will be repaired to a certain extent. The corrosion current density (I_corr) of the 600 °C sample in the kinetic potential test (5.32 × 10⁻⁴ A/cm²) was 54% lower than that of the naked SS 316 L (1.17 × 10⁻³ A/cm²). In the electrostatic potential test, the corrosion current of the 600 °C sample stabilized at a low value (about 0.26 μA/cm²), with the lowest concentration of dissolved metal ions (Fe²⁺ 2.908 mg/L). After anodic electrostatic potential polarization, the interfacial contact resistance (ICR) of (Mo+C)_600-1 was much lower than that of the untreated SS 316 L. Heat treatment experiments show that samples treated at 600 °C for 1 h exhibit significantly higher conductivity and anodic corrosion resistance than naked SS 316 L. This improvement is mainly due to the heat treatment under these conditions, which facilitated the formation of Mo carbides from the implanted C and Mo elements. Ion implantation and heat treatment enhance stainless steel surface conductivity and passive film corrosion resistance. These findings are useful in altering stainless steel BPs. Full article

This study investigates the potential for affordable and lightweight polymer electrolyte membrane fuel cells (PEMFCs) using lightweight flow-field plates, also referred to as bipolar plates. A comparative analysis was conducted on the performance of metal-coated and uncoated three-dimensional (3D)-printed flow-field plates, as well as that of a conventional graphite flow-field plate. The fabrication of these lightweight flow-field plates involved the application of sputtering and 3D printing technologies. The polarization curves and corresponding electrochemical impedance spectra of PEMFCs with metal-coated 3D-printed, uncoated 3D-printed, and graphite flow-field plates were measured. The results demonstrate that the metal-coated 3D-printed flow-field plate exhibits a gravimetric power density of 5.21 mW/g, while the graphite flow-field plate registers a value of 2.78 mW/g, representing an 87.4% improvement in gravimetric power density for the metal-coated 3D-printed flow-field plate compared to the graphite flow-field plate. These findings suggest the feasibility of reducing the weight of PEMFCs using metal-coated 3D-printed flow-field plates. Full article

Composite bipolar plates are a new class of material bipolar plates for PEMFCs. However, their application is limited by problems such as the difficulty of balancing their strength/conductivity properties. In this paper, by using surface-modified carboxylated short-cut carbon fibers and hydroxylated carbon nanotubes as well as PI resin, the interfacial bonding between the carbon-based filler and the resin is effectively improved under the premise of ensuring electrical conductivity, which enhances the flexural strength. The effect of the surface modification of the filler on the interfacial bonding between the filler and the PI resin is thoroughly investigated through molecular dynamics simulations. The mechanism for this improved bonding was also studied. Through the surface modification of the filler, the composite bipolar plates possessed a flexural strength of 49.06 MPa and a planar conductivity of 228.52 S/cm with the addition of 6% MWCNT-OH as well as 12% CCFs, which has the potential to be an optional substrate for composite bipolar plates. Full article

Air-cooled proton exchange membrane fuel cells (PEMFCs) offer advantages such as light weight, compact size, and simple structure, and have been widely used in fields such as portable electronics, drones, and new energy electric vehicles. However, due to the influence of air convective cooling efficiency, air-cooled PEMFC can only operate at low power to avoid overheating. To improve the air-cooling efficiency and the maximum output power of PEMFCs, a new enhanced cooling structure has been proposed, which adds secondary micro-channels on the surface of the original bipolar plate flow channels. Thermal simulation analysis was conducted for flow channels with and without an array of micro-channels on the surface. Through orthogonal simulation experiments, the optimal geometric parameters for the secondary micro-channels were determined. The simulation results show that for flow channels with optimized secondary micro-channels, the maximum temperature at the center plane of the MEA is reduced by approximately 10 °C, the thermal resistance of heat transfer in the channel decreases by about 21.2%, and the experimental results on heat transfer in the channel indicate that the maximum heat flux density increases by approximately 22.5%. Finally, performance tests were conducted on air-cooled PEMFC stacks with and without enhanced cooling secondary micro-channels. The test results show that the fuel cell stack with enhanced cooling secondary micro-channels exhibits a temperature reduction of approximately 14 °C at a current density of 0.5 A/cm², a maximum output power increase of about 27%, and improved voltage uniformity across individual cells, demonstrating the effectiveness of the enhanced cooling secondary micro-channel structure. Full article

Adding blockages to the gas flow channels in the bipolar plates has a significant effect on the performance of the proton exchange membrane fuel cell (PEMFC). The design parameters of the gas flow channels with blockages mainly include the blockage shape (S), blockage number (N), blockage height (H), and channel–rib width ratio (CRWR) value. This paper systematically examines the combined effects of S, N, H, and CRWR value on current density (I), pressure drop (ΔP), net output power (W_net), and non-uniformity of oxygen distribution (NU) of PEMFC through the application of the orthogonal experimental method (OEM). To provide a comprehensive optimization strategy, a novel multi-criteria decision framework is introduced, which integrates the analytic hierarchy process (AHP) and entropy weight method (EWM) to balance different evaluation objectives. Results from the AHP-EWM analysis reveal that the weight values of I, ΔP, W_net, and NU are 0.415, 0.08, 0.325, and 0.18, respectively. The CRWR value exhibits the greatest effect on the comprehensive performance of PEMFC, followed by H, N, and S. The optimal design parameter combination identified in this paper is a triangular blockage with nine blockages, a height of 0.8 mm, and a CRWR value of 0.25, corresponding to the highest comprehensive score of 31.8306 among the 25 groups of orthogonal experiments. This paper provides a new optimization perspective and certain guidance for the performance optimization direction of PEMFC. Full article

This study examines the impact of key stamping process parameters on metallic bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) performance using computational fluid dynamics (CFD) combined with thermal and electrochemical simulations and applying the design of experiments based on the Taguchi method. An exhaustive study on this topic is not found in the literature, and this study aims to identify the most influential parameters and their interactions to optimize channel geometries for enhanced PEMFC performance within manufacturing limits. Main effects analysis revealed the BP–GDL contact length-to-pitch ratio as the most influential parameter, achieving the best performance at its higher end (0.4). The external radius showed improved performance at a lower value (0.14 mm), while pitch and channel height had smaller effects, favoring lower values (1 mm and 0.3 mm, respectively). The channel angle exhibited minimal impact but slightly improved performance at 35°. Interaction analysis highlighted a complex relationship between pitch and angle, indicating that their combined effects on current density vary with specific value combinations. A higher pitch (2.5 mm) reduced performance with lower angles, whereas a lower pitch (1 mm) improved performance with reduced angles. Finally, two new geometrical designs derived from these optimized parameter combinations enhanced fuel cell performance by 1.97% and 1.23% over the baseline, demonstrating the Taguchi method’s value in optimizing the geometrical design of metallic bipolar plates in PEMFCs. These findings contribute to advancing more efficient and practical fuel cell technologies. Full article

With the escalating global demand for clean energy, the proton exchange membrane fuel cell (PEMFC), as an efficient and environmentally friendly energy conversion device, has emerged as a pivotal component of new power systems, playing a crucial role in achieving global carbon emission reduction targets. At present, the application of PEMFC technology is gradually expanding to the shipping industry and other fields, indicating its potential role in the future transformation of the energy structure. This article focuses on the marine salt spray environment; summarizes the impact of salt ionic contamination on PEMFC performance in recent years; and mainly explores the influence mechanism of the internal components of PEMFC, including the bipolar plate, the gas diffusion layer, catalyst layer, and proton exchange membrane. In addition, this study analyzes and summarizes the polarization curve variations in the marine salt spray environment, as well as the recovery methods after contamination, in order to provide certain references of PEMFC research for marine application. Full article

PEMFCs’ operation entails the presence of heterogeneities in the generation of current, heat and water along the active surface area. Indeed, PEMFCs are open systems, and as such, operating heterogeneities are inherent to their operation. A review of the literature reveals numerous attempts to achieve uniform current density distribution. These attempts are primarily focused on bipolar plate design and operating conditions, with the underlying assumption that uniform current density correlates with enhanced performance. Most studies focus on the influence of gas flow-field design and inlet hydrogen and air flow conditioning, and less attention has been paid to the coolant operating condition. However, uncontrolled temperature distribution over a large cell active surface area can lead to performance loss and localized degradations. On this latter point, we notice that studies to date have been confined to a narrow range of operating conditions. It appears that complementary durability studies are needed in order to obtain in-depth analyses of the coupled influence of temperature distribution and gas humidification in large PEMFCs. Full article