Search Results (16)

The hydrophilicity of the porous transport layer (PTL) critically influences the mass transport overpotential and overall efficiency of a proton exchange membrane water electrolyzer (PEMWE). In this study, titanium felts with three distinct levels of hydrophilicity are systematically characterized and evaluated electrochemically. A novel bilayer gradient hydrophilic titanium felt structure is designed, resulting in notable performance improvements: the average cell voltage decreases by 12.92%, and the overpotential is reduced by 9.94–18.03% across a current density range of 0.1–1.6 A·cm⁻². High-speed imaging reveals that the gradient hydrophilic structure effectively regulates bubble dynamics, nearly eliminating annular flow bubbles, reducing the proportion of slug flow bubbles by 40.78%, decreasing the bubble detachment diameter by 28.26%, and enhancing bubble displacement by 51.03% compared to that of untreated titanium felt. These results demonstrate that gradient hydrophilic structures can significantly enhance PEMWE performance, offering a promising strategy and a theoretical foundation for optimizing mass transfer in electrolytic systems. Full article

Proton exchange membrane water electrolyzers (PEMWEs) are an emerging hydrogen production technology with significant advantages. However, their structural design remains incompletely matured. During assembly, the clamping force is transmitted through the endplate to internal components. Improper clamping force causes uneven stress distribution across electrolysis cells, compromising sealing integrity and hydrogen production efficiency. To address uneven force transmission in conventional rectangular endplates, this study proposes a curved stack-facing endplate structure. A multi-objective optimization methodology is employed to identify the optimal curvature radius, which provides pre-deformation compensation during operation. This enables the surface to flatten under clamping force and to ensure tight contact with underlying cells. After optimization, the standard deviation of deformation along each path on the single electrolysis cell decreased by over 10% and the standard deviation of equivalent stress along each path on the endplate dropped by more than 5%. Subsequently, an orthogonal experimental design considering curvature radius and bolt arrangement is conducted to find the optimal combination in stack assembly. The optimal combination is identified and compared with the stack equipped with the original rectangular endplate. The maximum deformation at the four corners of the optimized endplate decreases from 0.28399 mm to 0.27452 mm. Additionally, the stress concentration area in the optimized endplate is reduced by more than half. Results demonstrate significantly reduced stress concentration and substantially more uniform stress distribution in the optimized endplate. Full article

In recent years, green hydrogen production via water electrolysis driven by renewable energy sources has garnered increasingly significant attention. Among the various water electrolysis technologies, proton-exchange membrane water electrolysis (PEMWE) distinguishes itself owing to the unique advantages, including the compact architecture, high efficiency, rapid dynamic response, and high purity of the generated hydrogen. The membrane electrode assembly (MEA) serves as the core component of a PEM electrolyzer. And only a high-performance and stable MEA can provide a reliable platform for investigating the mass transport behavior within the porous transport layer (PTL). In this study, the MEA fabrication method was optimized by varying the ionomer-to-carbon (I/C) ratio, coating strategy, and anode Ir mass loading. As a result, the cell voltage was reduced from 1.679 V to 1.645 V at 1.0 A cm⁻², with a small degradation of 1.3% over 70 h of operation. Based on the optimized MEA, the effects of the structure and porosity of PTL on the mass transport behavior were further analyzed. After the PTL parameter optimization, the cell voltage was further reduced to 1.630 V at 1.0 A cm⁻², while a high-speed camera captured bubble dynamics in real time, showing the fast detachment of small oxygen bubbles. The integrated electrochemical and visualization results provide a useful guideline to designing both MEA and PTL for efficient PEMWE. Full article

To address the fluctuation and instability of renewable power generation and the steady-state demands of chemical processes, a single-channel, non-isothermal computational fluid dynamics 3D model was developed. This model explicitly incorporates the coupling effects of electrochemical reactions, two-phase flow, and heat transfer. Subsequently, the influence of key operating parameters on proton exchange membrane water electrolyzer (PEMWE) system performance was investigated. The model accurately predicts the current–voltage polarization curve and has been validated against experimental data. Furthermore, the CFD model was employed to investigate the coupled effects of several key parameters—including operating temperature, cathode pressure, membrane thickness, porosity of the porous transport layer, and water inlet rate—on the overall electrolysis performance. Based on the numerical simulation results, the evolution of the ohmic polarization curve under temperature gradient, the block effect of bubble transport under high pressure, and the influence mechanism of the microstructure of the multi-space transport layer on gas–liquid, two-phase flow distribution are mainly discussed. Operational strategy analysis indicates that the high-efficiency mode (4.3–4.5 kWh/Nm³) is suitable for renewable energy consumption scenarios, while the economy mode (4.7 kWh/Nm³) reduces compression energy consumption by 23% through pressure–temperature synergistic optimization, achieving energy consumption alignment with green ammonia synthesis processes. This provides theoretical support for the optimization design and dynamic regulation of proton exchange membrane water electrolyzers. Full article

Proton exchange membrane water electrolyzers (PEMWEs) are a promising technology for green hydrogen production. However, the adoption of PEMWE-based hydrogen production systems remains limited due to several challenges, including high material costs, limited performance and durability, and difficulties in scaling the technology. Computational modeling serves as a powerful tool to address these challenges by optimizing system design, improving material performance, and reducing overall costs, thereby accelerating the commercial rollout of PEMWE technology. Despite this, conventional models often oversimplify key components, such as porous transport and catalyst layers, by assuming constant porosity and neglecting the spatial heterogeneity found in real electrodes. This simplification can significantly impact the accuracy of performance predictions and the overall efficiency of electrolyzers. This study develops a mathematical framework for modeling variable porosity distributions—including constant, linearly graded, and stepwise profiles—and derives analytical expressions for permeability, effective diffusivity, and electrical conductivity. These functions are integrated into a three-dimensional multi-domain COMSOL simulation to assess their impact on electrochemical performance and transport behavior. The results reveal that although porosity variations have minimal effect on polarization at low voltages, they significantly influence internal pressure, species distribution, and gas evacuation at higher loads. A notable finding is that reversing stepwise porosity—placing high porosity near the membrane rather than the channel—can alleviate oxygen accumulation and improve current density. A multi-factor comparison highlights this reversed configuration as the most favorable among the tested strategies. The proposed modeling approach effectively connects porous media theory and system-level electrochemical analysis, offering a flexible platform for the future design of porous electrodes in PEMWE and other energy conversion systems. Full article

The recycling of proton exchange membrane water electrolyzer (PEMWE) raw materials is imperative due to their scarcity, cost, complexity and environmental impact. This is particularly true in the context of expanding electrolyzer manufacturing and reducing production costs. Developing comprehensive recycling strategies requires the creation of a model stack due to the diversity in stack design, structure and materials. The review-derived model presented here provides a sound basis and summarizes the variety of approaches found in the literature and industry. The holistically developed recycling chain, including dismantling, mechanical processing, hydrometallurgical processes and carbon reuse, is characterized by the complete recycling of materials, the reduced application of energy-intensive process steps and the avoidance of environmentally harmful processes. Emphasis is placed on demonstrating the non-destructive disassembly of joined components, the dry mechanical decoating of catalyst-coated membranes, membrane dissolution, the separation of anode and cathode particles and the environmentally friendly hydrometallurgical processing of platinum. Full article

The proton exchange membrane water electrolysis (PEMWE) technology is a highly promising method for hydrogen production. The flow field structure is a key factor affecting the electrolyzer’s performance and overall cost. The commonly used flow field designs are typically parallel flow fields or serpentine flow fields. However, parallel flow fields often suffer from an uneven distribution of reactants, which can negatively impact electrolyzer performance. Serpentine flow fields, on the other hand, exhibit higher pressure drops, leading to increased energy consumption. Furthermore, research on circular planar flow field designs in PEMWE has been limited. Therefore, this study proposes a novel annular flow field design based on a circular plane using Murray’s branching law, with comparative analysis against parallel and serpentine flow fields. This design aims to address the aforementioned issues. A three-dimensional numerical model coupling multiple physical fields was developed with the aim of verifying the effectiveness of the annular flow field design in terms of pressure drop, velocity distribution, temperature distribution, hydrogen distribution, and polarization curves. To confirm the model’s reliability, bipolar plates with the novel annular flow field were fabricated and assembled into a single cell for validation. The results show that the novel annular flow field exhibits optimal electrolytic performance and can significantly improve the uniformity of flow and temperature distribution in PEMWE. At a voltage of 2.6 V, the current density increased by 29.99% and 13.84% compared to the parallel and serpentine flow fields, respectively. The velocity distribution was the most uniform, and the average temperature of the Membrane Electrode Assembly (MEA) decreased by approximately 6.08 K and 6.84 K compared to the parallel and serpentine flow fields, respectively. Notably, the pressure drop of the annular flow field was significantly reduced, with reductions of 53.63% and 46.09% compared to the parallel and serpentine flow fields, respectively. This study provides an effective solution for the design of circular plane flow fields in PEMWE. Full article

A novel design of a proton exchange membrane electrolyzer is presented. In contrast to previous designs, the flow field plates are round and oriented horizontally with the feed water entering from a central hole and spreading evenly outward over the anode flow field in radial, interdigitated flow channels. The cathode flow field consists of a spiral channel with an outlet hole near the outside of the bipolar plate. This results in anode and cathode flow channels that run perpendicular to avoid shear stresses. The novel sealing concept requires only o-rings, which press against the electrolyte membrane and are countered by circular gaskets that are placed over the flow channels to prevent the membrane from penetrating the channels, which makes for a much more economical sealing concept compared to prior designs using custom-made gaskets. Hydrogen leaves the electrolyzer through a vertical outward pipe placed off-center on top of the electrolyzer. The electrolyzer stack is housed in a cylinder to capture the oxygen and water vapor, which is then guided into a heat exchanger section, located underneath the electrolyzer partition. The function of the heat exchanger is to preheat the incoming fresh water and condense the escape water, thus improving the efficiency. It also serves as internal phase separator in that a level sensor controls the water level and triggers a recirculation pump for the condensate, while the oxygen outlet is located above the water level and can be connected to a vacuum pump to allow for electrolyzer operation at sub-ambient pressure to further increase efficiency and/or reduce the iridium loading. Full article

Water electrolysis for hydrogen production is of great importance for the reliable use of renewable energy sources to have a clean environment. Electrolyzers play a key role in achieving the carbon-neutral target of 2050. Among the different types of water electrolyzers, proton exchange membrane water electrolyzers (PEMWEs) represent a well-developed technology that can be easily integrated into the smart grid for efficient energy management. In this study, a discrete dynamic mathematical model of a PEMWE was developed in MATLAB/Simulink to simulate cell performance under various operating conditions such as temperature, inlet flow rate, and current density loads. A lab-scale test bench was designed and set up, and a 5 cm² PEMWE was tested at different temperatures (40–80 °C) and flow rates (3–12 mL/min), obtaining Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV), Chrono-potentiometry (CP), and Electrochemical Impedance Spectroscopy (EIS) results for comparison and adjustment of the dynamic model. Sensitivity analysis of different operating variables confirmed that current density and temperature are the most influential factors affecting cell voltage. The parametric sensitivity of various chemical–physical and electrochemical parameters was also investigated. The most significant ones were estimated via non-linear least squares optimization to fine-tune the model. Additionally, strong correlations between these parameters and temperature were identified through regression analysis, enabling accurate performance prediction across the studied temperature range. Full article

Hydrogen (H₂) is a key energy vector in the global transition toward clean and sustainable energy systems. Among the various production methods, water electrolysis presents a promising pathway for zero-emission hydrogen generation when powered by renewables. This review provides a comprehensive evaluation of water electrolysis technologies, including alkaline (AWE), proton exchange membrane (PEMWE), solid oxide (SOEC), anion exchange membrane (AEMWE), and microbial electrolysis cells (MEC). It critically examines their material systems, catalytic strategies, operational characteristics, and recent performance advances. In addition to reviewing experimental progress, the study presents a finite element modeling (FEM) case study that evaluates thermal and mechanical responses in PEM and AWE configurations—illustrating how FEM supports design optimization and performance prediction. To broaden methodological insight, other simulation frameworks such as computational fluid dynamics (CFD), response surface methodology (RSM), and system-level modeling (e.g., Aspen Plus^®) are also discussed based on their use in recent literature. These are reviewed to guide future integration of multi-scale and multi-physics approaches in electrolyzer research. By bridging practical design, numerical simulation, and material science perspectives, this work provides a resource for researchers and engineers advancing next-generation hydrogen production systems. Full article

Hydrogen peroxide is inevitably produced at the hydrogen electrode in both the proton exchange membrane fuel cell (PEMFC) and the proton exchange membrane water electrolyzer (PEMWE) when platinum-based catalysts are used. This peroxide attacks and degrades the membrane, seriously limiting its lifetime. Here we review some of our previous efforts to suppress peroxide production using PtFe as a hydrogen evolution reaction (HER) catalyst and PtCo as a hydrogen oxidation reaction (HOR) catalyst. The mechanisms, which involve the chemical reaction of adsorbed hydrogen with oxygen, are examined using density functional theory. The onset of excess peroxide production at 0.1 V above the reversible potential has not been adequately explained thus far, and therefore a new mechanism is proposed here. This involves a unique reaction site including hydrogen adsorbed at (110) step edges adjacent to (111) terraces on the Pt surface, as well as on Pt alloys and other metals such as Rh and Ir. This mechanism helps explain the recent finding of the Wadayama group that Ir single crystal surfaces such as Ir(111) and Ir(110) produce little peroxide during the HOR. It also points the way toward the design of new catalysts for the hydrogen electrode that suppress peroxide production while retaining high HOR and HER activity. Full article

The proton exchange membrane water electrolyzer (PEM-WE) is a well-known green technology for hydrogen production. The main obstacle to its development, on a large scale, is the sluggish kinetics of the oxygen evolution reaction (OER). At present, the design of acid-stable electrocatalysts with low overpotential and excellent stability for the OER constitutes an important activity in electrocatalysis. This review presents an analysis of the fundamentals and strategies for the design of advanced electrocatalysts for oxygen evolution, reaction mechanisms, and OER descriptors. The scrutiny of OER electrocatalysts, with elemental composition from single- to multielemental, are presented. In addition, the purpose of high-entropy alloys (HEAs), a recent research strategy, for the design of advanced materials is summarized. Briefly, the effect of support materials, which are beneficial for modulating the electronic properties of catalysts, is presented. Finally, the prospects for the development of acidic OER electrocatalysts are given. Full article

The proton exchange membrane water electrolyzer (PEMWE) requires a high operating voltage for hydrogen production to accelerate the decomposition of hydrogen molecules so that the PEMWE ages or fails. According to the prior findings of this R&D team, temperature and voltage can influence the performance or aging of PEMWE. As the PEMWE ages inside, the nonuniform flow distribution results in large temperature differences, current density drops, and runner plate corrosion. The mechanical stress and thermal stress resulting from pressure distribution nonuniformity will induce the local aging or failure of PEMWE. The authors of this study used gold etchant for etching, and acetone was used for the lift-off part. The wet etching method has the risk of over-etching, and the cost of the etching solution is also higher than that of acetone. Therefore, the authors of this experiment adopted a lift-off process. Using the flexible seven-in-one (voltage, current, temperature, humidity, flow, pressure, oxygen) microsensor developed by our team, after optimized design, fabrication, and reliability testing, it was embedded in PEMWE for 200 h. The results of our accelerated aging test prove that these physical factors affect the aging of PEMWE. Full article

Integrating the exergy and economic analyses of water electrolyzers is the pivotal way to comprehend the interplay of system costs and improve system performance. For this, a 3D numerical model based on COMSOL Multiphysics Software (version 5.6, COMSOL, Stockholm, Sweden) is integrated with the exergy and exergoeconomic analysis to evaluate the exergoeconomic performance of the proton exchange membrane water electrolysis (PEMWE) under different operating conditions (operating temperature, cathode pressure, current density) and design parameter (membrane thickness). Further, the gas crossover phenomenon is investigated to estimate the impact of gas leakage on analysis reliability under various conditions and criteria. The results reveal that increasing the operating temperature or decreasing the membrane thickness improves both the efficiency and cost of hydrogen exergy while increasing the gas leakage through the membrane. Likewise, raising the current density and the cathode pressure lowers the hydrogen exergy cost and improves the economic performance. The increase in exergy destroyed and hydrogen exergy cost, as well as the decline in second law efficiency due to the gas crossover, are more noticeable at higher pressures. As the cathode pressure rises from 1 to 30 bar at a current density of 10,000 A/m², the increase in exergy destroyed and hydrogen exergy cost, as well as the decline in second law efficiency, are increased by 37.6 kJ/mol, 4.49 USD/GJ, and 7.1%, respectively. The cheapest green electricity source, which is achieved using onshore wind energy and hydropower, reduces hydrogen production costs and enhances economic efficiency. The growth in the hydrogen exergy cost is by about 4.23 USD/GJ for a 0.01 USD/kWh increase in electricity price at the current density of 20,000 A/m². All findings would be expected to be quite useful for researchers engaged in the design, development, and optimization of PEMWE. Full article

As the environmental considerations rise all over the world and under the drive of renewable energy policy, the society of hydrogen energy will come out gradually in the future. The proton exchange membrane water electrolyzer (PEMWE) is a very good hydrogen generator, characterized by low cost, high efficiency and zero emission of greenhouse gases. In this study, the micro temperature, humidity, flow, pressure, voltage, and current sensors were successfully integrated on a 50 μm thick Polyimide (PI) substrate by using micro-electro-mechanical systems (MEMS) technology. After the optimal design and process optimization of the flexible 6-in-1 microsensor, it was embedded in the PEMWE for a 500-h persistent effect test and internal real-time microscopic monitoring. Full article