Proton Exchange Membrane Fuel Cell Research Articles

Design and Study of Wave Flow Field in Bipolar Plates for Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cell (PEMFC) is an efficient energy conversion device that converts hydrogen and oxygen directly into electricity through a chemical reaction. In PEMFC, the bipolar plate plays a crucial role, responsible for the collection and transfer of current and the distribution of reactant gases. The wave flow channel bipolar plate is a new design designed to improve the performance of the battery, including enhancing the mass transfer efficiency and reducing the pressure drop. By comparing the advantages and disadvantages of other flow channels, this paper analyzes the conclusion that the wave flow field is more prominent in the comprehensive aspect. It is observed that the wave flow field can effectively increase the length of the flow path and improve the distribution of reactant gas by comparing the traditional flow path with the wavy flow path.

Post mortem Study of Catalyst Degradations Occurring in High-Temperature Proton Exchange Membrane Fuel Cells Upon Start-Stop Operation

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) could replace fossil fuel-based technologies for applications which cannot involve bulky/heavy cooling systems, such as aeronautics. However, severe materials degradations upon operation prevent performance retention for acceptable lifetimes. While others have already reported degradations in HT-PEMFC, post mortem characterizations of used HT-PEMFC membrane electrode assemblies (MEAs) remain scarce. Herein, HT-PEMFC performance degradation is studied by applying a startup/shutdown protocol to a short-stack operated at 160 °C; one MEA is characterized using complementary physicochemical/electrochemical techniques to identify/understand the degradation mechanisms and their origin. This start/stop operation mode (co-flow gas reactants) leads to substantial degradation inhomogeneity. For the anode, migration, coalescence, and detachment of Pt nanoparticles are witnessed induced by high-surface-area carbon support functionalization and corrosion. The anode electrochemical surface area (ECSA) remains constant at the inlet and increases significantly at the outlet, following inhomogeneous degradation of the cathode catalyst: the Ptz+ ions formed at high potential/oxidizing conditions concentrate towards the outlet, where they redeposit locally or at the anode, after diffusion/migration across the PBI membrane. Hence, the cathode ECSA decreases significantly at the inlet. Furthermore, intense Ni-leaching from the initial PtNi alloy catalyst is reported as a result of O2 mass-transport and phosphoric acid dilution inhomogeneity.

A Universal Strategy to Enhance Polarization Performance and Anode Reversal Tolerance by Polyaniline-Coated Carbon Support for Proton Exchange Membrane Fuel Cells.

Anode cell reversal typicallyleads to severe carbon corrosion and catalyst layer collapse, which significantly compromises the durability of proton exchange membrane fuel cells. Herein, three types of commercial carbon supportswith various structures are facilely coated by polyaniline (PANI) and subsequently fabricated into reversal-tolerant anodes (RTAs). Consequently, the optimized PANI-coated catalyst RTAs demonstrate enhanced polarization performance and improved reversal tolerance compared to their uncoated counterparts, thus confirming the universality of this coating strategy. Essentially, the surface engineering introduced by PANI coating incorporates abundant N-groups and enhances coulombic interactions with ionomer side chains, which in turn reduces lower carbon exposure, promotes more uniform Pt deposition, and ensures better ionomer distribution. Accordingly, the membrane-electrode-assembly containing the Pt/PANI/XC-72R-1+IrO2 RTA presents a 100mV (at 2500mAcm-2) polarization performance improvement and 26-fold reduction in the degradation rate compared to theuncoated counterpart. This work provides a universal strategy for developing durable anodes and lays the groundwork for the practical fabrication of high-performance, low-degradation RTA.

The Corrosion Characteristics of Graphite Coatings on Nickel Foam and Their Applications in High-Temperature Proton Exchange Membrane Fuel Cells

This study investigates the effectiveness of graphite coatings on nickel foam for use in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). Nickel foam, known for its high porosity and good conductivity, serves as an advantageous alternative to traditional flow channels but faces corrosion challenges in HT-PEMFCs, especially from phosphoric acid leakage. Graphite coatings are used as the protection layer and compared with nitride coatings. Chemical vapor deposition process parameters are first optimized for graphite growth. Corrosion polarization curves are then measured using a high-temperature phosphoric acid three-electrode system simulating HT-PEMFC conditions, followed by an analysis of the surface morphology of the samples. Subsequently, the performance and durability of the nickel foams with different coatings are evaluated after being assembled in single fuel cells. The results highlight the superior corrosion resistance of graphite coating under HT-PEMFC conditions, demonstrating its performance over other coatings. Graphite-coated foams showed a significant reduction in corrosion current, approximately 58% lower than uncoated foams and 21% lower than the TiN coated foams. In practical applications, an HT-PEMFC single cell with graphite-coated nickel foam demonstrated a current density of 763 mA/cm2 at 0.6 V under conditions of 180 oC and 2 atm H2/air. The current density is 40% higher than that of the uncoated nickel foam. The results show notable long-term durability under constant current holding tests at 160 oC. The voltage decay rate in the graphite-coated cell was 48% lower compared to the cell with uncoated nickel forms.

Polydopamine modified carbon fiber to improve the comprehensive properties of carbon paper for proton exchange membrane fuel cell

In this study, polydopamine (PDA) was used to modify functional groups on the surface of carbon fiber (CF), and the effects of different dopamine hydrochloride (DPH) concentrations on the surface morphology, functional groups, contact angle and dispersion stability of CF were studied. Subsequently, the raw carbon paper (RCP), hot-pressed carbon paper (HPCP) and carbon paper (CP) were prepared successively using the modified CF through wet forming, impregnation/hot-pressing, and carbonization methods. The surface morphology, tensile strength, flexural strength, electrical resistivity, air permeability and pore size distribution were analyzed for these materials. It was observed that the introduction of −OH and − NH2 groups improved the hydrophilicity and dispersion of PDA modified CFs, resulting in an increase in formation index (FI) from 39.2 to 48.1 for RCP samples. With increasing DPH concentration, the tensile strength of CP initially increased but then decreased while its electrical resistivity showed an opposite trend. Finally, PDA modified CP was assembled into proton exchange membrane fuel cells (PEMFC). The PEMFC assembled from DPH-CP-2.5 achieved a maximum limiting current density of 1440.0 mA/cm2 and power density of 458.25 mW/cm2. Meanwhile, the lower material transmission impedance for DPH-CP-2.5 as well as excellent water management ability and gas transmission performance.

Graphene composite coating for enhanced corrosion resistance of Ni foam flow field in PEMFC

With the development of proton exchange membrane fuel cells (PEMFCs), metal foam with lightweight advantages and highly porous structures has become promising flow field material to replace traditional carbon plates. However, in the operating environment with high temperatures and acid situation, it suffers severe corrosion issues. To solve this problem, Sn and Sn/graphene composite coatings are prepared and the physical characteristics are analyzed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Tafel polarization test, potentiostat test, and electrochemical impedance spectroscopy are used to test the corrosion resistance of coated nickel foam in a PEMFC cathodic environment. Compared to Sn-coated foam, the corrosion resistance is further enhanced with the addition of graphene. The Sn/graphene coating obtained by electrodeposition at current density of 15mA·cm–2 has the lowest corrosion current density, which accounts for only 41.20% and 33.48% of the uncoated foam value at 50°C and 80°C, respectively. It also exhibits the maximum coating resistance, the lowest potentiostatic current and interfacial contact resistance, which is 66.3% lower than the US DOE 2025 goal. After an 8h constant potential test, no noticeable pitting behavior is shown on the surface because of the compact Sn/graphene coating. The addition of graphene promotes the nucleation of Sn metal and results in lower Sn oxidation.

Prediction of polarization curves of PEMFC membrane electrode assembly using artificial intelligence technics

Proton exchange membrane fuel cells (PEMFCs) are used commercially in automobiles, buses, uninterruptible power supplies, and combined heat power systems, holding a significant place in the fuel cell market. Fuel cell performance is characterized by polarization curves in design and manufacturing processes. This study predicts a PEMFC’s polarization curves using comparative artificial intelligence (AI) models trained and tested under different operational conditions. The AI model inputs are cell temperature, humidity, anode-cathode flow, and membrane resistance. The outputs are cell voltage and current density. The model outputs are compared with experimental values for 50°C, 100% humidity using MATLAB software. The average Root Mean Square Error (RMSE) for the ANFIS prediction is 0.056112, while for the ANN prediction it is 0.011919. These results indicate that the Artificial Neural Network (ANN) method outperforms the Adaptive Neuro Fuzzy Inference System (ANFIS) in predicting the behavior of the PEMFC’s Membrane Electrode Assembly (MEA). The models showed promising results with high accuracy.

Effects of Sodium Chloride on PEMFC Durability at a Concentration Close to that of a Marine Environment

The marine application of proton exchange membrane fuel cells (PEMFCs) requires special attention due to sea salt aerosols and atmospheric pollutants, susceptible to degrade these systems and induce performance losses. To the best of our knowledge, this study is the first to identify the performance losses of PEMFCs due to sodium chloride (NaCl) pollution similar to that of the marine environment. A 641 h ageing test with a NaCl concentration in air of 120 μg.m‒3 was carried out on a five cells stack of 220 cm2. The results reveal a key mechanism for reversible performance loss, namely the deposition of salt particles in the channels and on the surface of the cathode gas diffusion layer (GDL). This can lead to the complete shutdown of a cell. Nonetheless, this contamination did not induce significant irreversible performance losses as the restarts of the stack cause the salt particles to dissolve. An overall degradation rate of 8 μV·h‒1, similar to that of the baseline without NaCl contamination, is observed.

Graphene oxide/polydopamine interface co-reinforced carbon paper: With comprehensive mechanical properties, electrical conductivity and air permeability

Proton Exchange Membrane Fuel Cell ( PEMFC) are characterised by their cleanliness, efficiency and lack of pollution. Carbon paper, the fundamental material for constructing gas-diffusion layer (GDL), plays a crucial role in electron transmission, supporting the electrode structure, and proton transport. However, the traditional carbon paper for GDL significantly limits the large-scale commercial application of PEMFC due to its low mechanical strength and poor conductivity. Based on this, in this paper, polydopamine is used to modify primary carbon fiber paper, a homogeneous mixed solution of graphene oxide and phenolic resin is used as the impregnating agent, and the effects of different GO concentrations on the properties of carbon paper are investigated. The results show that the graphitization degree and mechanical properties of carbon paper are improved with the increase of GO concentration. When the content of polydopamine is 2 g/L and the concentration of GO is 0.5 wt%, the carbon paper exhibits optimal performance. The air permeability of carbon paper is 12.18 L/min, the resistivity is 13.5 mΩ·cm, and the tensile strength is 19.3 MPa. This study provides a simple method for preparing highly breathable and highly conductive carbon paper, offering a reference for achieving low-cost and high-performance carbon paper production, and facilitating the large-scale commercial production of carbon paper.

Advanced Methodology for Simulating Local Operating Conditions in Large Fuel Cells Based on a Spatially Averaged Pseudo-3D Model

To address the performance and lifetime limitations of Proton Exchange Membrane Fuel Cells, it is essential to have a comprehensive understanding of the operating heterogeneities at the cell scale, requiring the test of a wide range of operating conditions. To avoid experimental constraints, numerical simulations seem to be the most viable option. Hence, there is a need for time-efficient and accurate cell-scale models. In this intention, previous works led to the development and the experimental calibration of a pseudo-3D model of a full-size cell in a stack. To further reduce the computation time, a new spatially averaged, multi-physics, single-phase, non-isothermal, steady state pseudo-3D model is developed and calibrated with the results of the preceding model. Particularly, it captures the influence of the coolant on temperature and water mappings in the cell. Moreover, a new methodology is proposed to calibrate the electrochemical cell voltage law for new membrane-electrode assemblies. The emulation of the local operation conditions in large active surface area is realized with a small differential cell, avoiding the testing of large single cells or stacks. Subsequently, simulations are conducted to investigate the impact of the coolant temperature gradient, coolant outlet temperature and gas relative humidity.

A Holt Trend-Enabled Attention-ConV-GRU Method for Long-Term Degradation Prediction of Fuel Cells

Abstract Proton Exchange Membrane Fuel Cell (PEMFC) has attracted widespread attention as a promising energy conversion device. However, the lack of durability is one of the major reasons limiting the further development of PEMFC. Accurately predicting the Remaining Usable Life (RUL) of a PEMFC is a key prerequisite for durability enhancement. This paper is dedicated to addressing the limitations of the training data interval for RUL prediction performance. Based on the above ideas, we propose a Holt trend-enabled Attention-Convolution-Gated Recurrent Unit method for extracting trend information and making multi-step predictions. The experimental results show that this strategy improves the multi-step prediction and maintains the inherent degradation trend over a longer range of time steps. The Root Mean Square Error and Mean Absolute Error both fell by more than 45%. The prediction accuracy reach 93.76%.

Cover Picture: Fundamental and Practical Aspects of Break‐In/Conditioning of Proton Exchange Membrane Fuel Cells (Chem. Rec. 10/2024)

Cover Picture: Fundamental and Practical Aspects of Break‐In/Conditioning of Proton Exchange Membrane Fuel Cells (Chem. Rec. 10/2024)

Strong metal-support interaction induced by oxygen vacancies to enhance the activity and durability of Pt/TiO2/ hollow carbon nanospheres ORR catalyst

For the commercial Pt-loaded carbon ORR catalysts used in proton exchange membrane fuel cells (PEMFC), carbon support corrosion, along with the migration and aggregation of Pt nanoparticles (NPs) due to the weak interaction between Pt NPs and carbon, leads to a drastic reduction in both electrocatalytic activity and stability. Hence, exploring active and steady supports is crucial to restrain the activity loss and stabilize Pt catalysts. In this work, a composite support consisting of hollow carbon nanospheres (HC) and TiO2 NPs with abundant oxygen vacancies (OV) loaded with Pt NPs (PTHC-H) was designed and synthesized. Experiment results show that PTHC-H exhibits superior activity and stability compared to PTHC-N (TiO2 with lower OV content) and commercial Pt/C catalyst. Specifically, PTHC-H delivers a half-wave potential of 0.883V versus reversible hydrogen electrode. And its mass activity and half-wave potential decrease by only 15.96% and 7mV, respectively, after 10,000 cycles of accelerated durability testing. The excellent activity and stability are ascribed to the enhanced metal-support interaction induced by OV, which can optimize the Pt d-band center and suppresses the migration and aggregation of Pt NPs. This work may be favorable for designing efficient and durable anti-corrosion nano catalysts.

Integrating Pt–Co Nanoalloy and Sulfur-Doped Co–N–C to Construct Oxygen Reduction Reaction Catalysts for Proton Exchange Membrane Fuel Cells

Integrating Pt–Co Nanoalloy and Sulfur-Doped Co–N–C to Construct Oxygen Reduction Reaction Catalysts for Proton Exchange Membrane Fuel Cells

Adaptive hierarchical energy management strategy for fuel cell mobile robot hybrid power system based on working condition recognition

Energy management of hybrid power is critical to maintain the economical and efficient operation of fuel cell mobile robots. To improve the energy distribution between the proton exchange membrane fuel cell (PEMFC) and battery under different working conditions, this paper proposes an adaptive hierarchical energy management strategy (AHEMS) based on the recognition and management levels. Firstly, the recognition level realizes the identification of different working conditions based on the machine learning (ML) methods including the K-means and KNN. Secondly, the fuel cell hydrogen consumption and efficiency are both optimized by adaptive multi-objective particle swarm optimization (AMOPSO) at the management level. Specifically, an adaptive flight parameter strategy based on the particle dispersity (PD) information is proposed to balance the convergence and diversity of Pareto solutions. Besides, to overcome the parameter uncertainty caused by different working states and improve the system performance, an interval optimization scheme is proposed based on the Pareto solutions. Finally, the fuzzy decision combined with the recognition results and state of charge (SOC) of the battery is performed to find the most appropriate power distribution of the PEMFC and battery. The proposed AHEMS algorithm is compared with different algorithms in the numerical simulation and hardware-in-loop (HIL) experiments. These results demonstrate that the hybrid power system with the proposed optimization scheme performs better than the base model and classical optimization algorithms in terms of the hydrogen consumption and efficiency indexes, revealing the success of this AHEMS approach in solving the energy distribution problem in different working conditions.

Novel, Fluorine-Free Membranes Based on Sulfonated Polyvinyl Alcohol and Poly(ether-block-amide) with Sulfonated Montmorillonite Nanofiller for PEMFC Applications.

Novel blend membranes containing S-PVA and PEBAX 1657 with a blend ratio of 8:2 (referred to as SPP) were prepared using a solution-casting technique. In the manufacturing process, sulfonated montmorillonite (S-MMT) in ratios of 0%, 3%, 5%, and 7% was used as a filler. The crystallinity of composite membranes has been investigated by X-ray diffraction (XRD), while the interaction between the components was evaluated using Fourier-transform infrared spectroscopy (FT-IR). With increasing filler content, good compatibility between the components due to hydrogen bonds was established, which ultimately resulted in improved tensile strength and chemical stability. In addition, due to the sulfonated moieties of S-MMT, the highest ion exchange capacity (0.46 meq/g) and water uptake (51.61%) can be achieved at the highest filler content with an acceptable swelling degree of 22.65%. The composite membrane with 7% S-MMT appears to be suitable for application in proton exchange membrane fuel cells (PEMFCs). Amongst the membranes studied, this membrane achieved the highest current density and power density in fuel cell tests, which were 149.5 mA/cm2 and 49.51 mW/cm2. Our fluorine-free composite membranes can become a promising new membrane family in PEMFC applications, offering an alternative to Nafion membranes.

The Influence of Membrane Thickness and Catalyst Loading on Performance of Proton Exchange Membrane Fuel Cells

This paper explores the influence of membrane thickness and catalyst loading on fuel cell performance of commercially relevant membrane electrode assemblies (MEAs). A systematic study was carried out with MEAs comprised of commercially available Pt/C electrocatalysts and reinforced PFSA membranes to better understand the practical limitations of incorporating low platinum loadings and ultra-thin membranes in commercially viable MEA designs. Three different MEA configurations were compared where membrane thickness was either 15 or 10 μm and cathode catalyst loading was either 0.4 or 0.1 mgPt cm−2. Extensive in situ electrochemical characterization was carried out to extract the relevant physical and electrochemical parameters of each MEA configuration. By changing only one variable at a time, i.e., either thickness or catalyst loading, it was possible to deconvolute the specific contributions of membrane thickness and catalyst loading on fuel cell performance. Interestingly, as membrane thickness was reduced below 15 μm, no significant changes in fuel cell performance were observed as membrane interfacial effects begin to dominate compared to bulk transport effects. Conversely, reducing catalyst layer loading from 0.4 to 0.1 mgPt cm−2 introduces significant polarization losses attributed to a combination of kinetic and mass transport effects.

Design and performance study of a kilowatt-class PEMFC stack with metal fiber felts as flow fields

The study presents a comprehensive design and evaluation of a kilowatt-class proton exchange membrane fuel cell (PEMFC) stack, wherein stainless steel fiber felts are innovatively utilized as flow fields. The impacts of critical operating parameters, namely operating temperature, pressure, and reactant gas relative humidity, on the performance of the 22-cell stack with an active area of 83 cm2 were thoroughly investigated. An analysis of the voltage consistency among individual cells was conducted across varying operating conditions and output currents. The total power output of the PEMFC stack reaches 1183W under the fundamental operating conditions, where each cell achieves an average voltage of 0.6V. As the operating temperature and pressure are incremented, the stack’s output power exhibits a noticeable increase. The optimal range for the reactant gas relative humidity is found to be 60% to 80%. As the output current increases, the voltages of individual cells gradually decrease and the voltage consistencies tend to deteriorate. The optimal operating conditions for achieving the best voltage consistency vary with current density.

Effect of High-Temperature Operation on Voltage Cycling Induced PEMFC Degradation: From Automotive Customer Drive Cycles to an Accelerated Stress Test

Degradation of the Pt catalyst during load cycling constitutes a major durability issue for proton exchange membrane fuel cells (PEMFCs) in automotive applications. In this study commercial 5 cm2 electrodes were exposed to 20 k voltage cycles between 0.6–0.9 VRHE at temperatures ranging from 75 to 120 °C. The electrochemical surface area (ECSA), the roughness factor (rf), and the oxygen transport resistance were investigated over the course of the test. The degradation was mainly governed by Pt agglomeration and was accelerated with increasing temperature. Interestingly, operation at high temperature (120 °C and 30% RH) caused the same ECSA loss as at standard conditions (90 °C and 90% RH), suggesting that when maintaining dry conditions high-temperature operation is not critical for the durability of the catalyst material. The experimental results were used to validate an existing 0D catalyst degradation model, which was then applied to an automotive customer drive cycle. The calculated degradation over the whole automotive lifetime (excluding startup shutdown and idle events) equals 20 k voltage cycles (0.6–0.9 V, 10 s hold time) at 90 °C and 30% RH, which provides a guideline for the assessment of the suitability of novel catalyst materials for automotive applications.

Optimization of hydrogen recirculation ejector for proton-exchange membrane fuel cells (PEMFC) systems considering non-equilibrium condensation

In proton exchange membrane fuel cell (PEMFC) systems, unconsumed hydrogen recirculation is enabled by utilizing an ejector, and the PEMFC system's efficiency is thereby enhanced. Apart from the structural parameters, an ejector's performance is also significantly affected by the non-equilibrium condensation phenomenon. Therefore, the ejector structural parameters' impact upon non-equilibrium condensation intensity and ejector efficiency is investigated under design conditions. Structural optimization of the ejector is performed within its operating range to uphold optimal efficiency in the presence of fluctuations in secondary flow pressure. The result shows that non-equilibrium condensation negatively affects the ejector's efficiency, but its impact diminishes with larger mixing chamber diameters and nozzle divergence angles. The optimized ejector performs best with a 2.40 mm diameter mixing chamber and an 11.0o nozzle divergence angle. On average, the optimized ejector's performance improves by 16.8%, reaching a maximum improvement of 22.8% within the effective operating range.