Proton Exchange Membrane Electrolysis Cell Research Articles

Particle swarm optimization of electric power generation via green hydrogen considering the performance of the electrolyzer cell

The replacement of energy generation models, from fossil fuels to carbon neutral ones, requires a significant transformation in the generation and consumption of electricity. This work highlights Green Hydrogen as an essential potential to intensify the energy generation process based on renewable sources. The article presents two studies on energy generation models, via Green Hydrogen: Case (i), study of the behavior of the Electric Activation Voltage with ohmic loss influenced by the control variables Electric Current and Operating Temperature. Case (ii), study of the behavior of the Electric Activation Voltage with ohmic loss influenced by the control variables Electric Current and Operating Pressure. For both cases, a computational model stands out, the Proton Exchange Membrane electrolyzer cells, indicated for the generation of renewable energy, from Green Hydrogen. For both cases, a Bioinspired Computing methodology was applied in order to optimize the process. The Optimization technique means, among the various definitions, determining the best set of results, considering the restrictions of the studied phenomenon. Studies indicate that this strategy is increasingly intrinsic to our reality. This paper advocates Particle Swarm Optimization as a mechanism capable of finding the best set of solutions for mathematical models related to Energy Systems. The Swarm Algorithm can be represented as a set of particles that navigate through a space of solutions, where the main element of this method is the exchange of information between the particles of the population, which allows collective mobilization towards the optimal solution. In this case specifically, the values of Electrical Voltage, Electrical Current, Operating Temperature and Pressure form the Particle Examination. The results were exceptional for the Green Hydrogen energy generation system studied. The Particle Swarm Optimization Algorithm was applied to the objective function of multiple variables and satisfactorily incorporated the restrictions and conditions of the electrolysis system. The measurements obtained highlight that the Optimal Values are lower than the Average Values, for each variable analyzed in energy generation, in an electrolyzer. The solution achieved will be of great applicability in the study of energy efficiency in structures linked to this relevant category of renewable energy generation.

A novel carbon coating by electrochemical deposition in deep eutectic solvent with the assistance of ammonium chloride for stainless steel bipolar plates

In this work, pulse electrodeposition method was proposed to directly deposit amorphous carbon coating (ACC) onto 316L stainless steel substrate in choline chloride-ethylene glycol deep eutectic solvent (DES) mixed with ammonium chloride (NH4Cl) to fabricate bipolar plates. The obtained dense ACC has a thickness of ∼400 nm. Potentiodynamic and potentiostatic polarization tests demonstrated that the corrosion current density of ACC coated 316L steel was of the order of 10−7 A cm−2 in the simulated proton exchange membrane fuel cells (PEMFC) working environment, and the self-corrosion potential of the coating positively shifted by 0.4V, indicating a significant improvement on corrosion resistance of the coated steel plate due to excellent electrochemical stability of ACC. The Rockwell C indentation test showed that the as-obtained ACC was strongly bonded to the substrate and also had high in-plane strength. Further numerical simulation and comparison experiments showed that C was chemically bonded with Fe in the substrate, which was boosted by the assistance of NH4Cl. The intact and strong bonding between ACC and the substrate is highly helpful to improve corrosion resistance. The success in coating stainless steel plate with ACC by pulse electrodeposition method provides a promising alternation for coating of proton exchange membrane electrolyzer cell (PEMEC) and PEMFC metal bipolar plates.

Process Parameter Optimization via RSM of a PEM based Water Electrolysis Cell for the Production of Green Hydrogen

In the present work, the operating parameters were optimized using Box Behnken Design (BBD) in response surface methodology (RSM) to maximize the hydrogen production rate (R1) and hydrogen production rate per unit watt consumed (R2) of a proton exchange membrane electrolysis cell (PEMEC), a third response (R3) which was the sum of the scaled values of R1 and R2 were selected to be maximized so that both hydrogen production rate and hydrogen production rate per unit watt consumed could be maximized. The major parameters which were influencing the experiment for enhancing the output responses were oxygen electrode/anode electrocatalyst loading (A), current supplied (B) and water inlet temperature (C). The commercial proton exchange membrane Nafion® was used as the electrolyte. The acetylene black carbon (CAB) supported IrO2 was used as the electrocatalyst for preparing oxygen electrode/anode whereas commercial Pt (40 wt%)/CHSA was used as the H2 electrode/cathode electrocatalyst. The quadratic model was developed to predict the output/responses and their proximity to the experimental output values. The developed model was found to be significant as the P values for both the responses were < 0.0001 and F values were greater than 1. The optimum condition for both the responses were O2 electrode/anode electrocatalyst loading of 1.78 mg/cm2, supplied current of 0.33 A and water inlet temperature of 54°C. The predicted values for hydrogen production rate (R1) and hydrogen production rate per unit watt consumed (R2) were 2.921 mL/min and 2.562 mL/(min·W), respectively obtained from the quadratic model. The error % between the predicted response values and experimental values were 1.47% and 3.08% for R1 and R2, respectively. This model predicted the optimum conditions reasonably in good agreement with the experimental conditions for the enhancement of the output responses of the developed PEM based electrolyser.

Effect of flow channel cross-section shape on the performance of proton exchange membrane electrolysis cell

To study the thermal and mass distribution in proton exchange membrane electrolytic cells (PEMEC), a two-phase numerical model of a single-channel electrolytic cell was established. The polarization performance and gas-heat distribution in a single-channel electrolytic cell under five different flow channel cross-sections (rectangle, trapezoid, inverted trapezoid, triangle, and circle) were studied. The findings indicate that the inverted trapezoidal flow channel’s gas buildup effect is rather severe in both the catalytic and diffusion layers. In the trapezoidal flow channel, the temperature of the proton exchange membrane region is lower, and the electrochemical performance of the rectangular flow channel electrolytic cell is the best, with an improvement rate of up to 11.47%. The electrochemical performance of the triangular and circular flow channels is the worst.

Graphene-based electrochemical system for tritium enrichment

In this study, a tritium enrichment system in the water phase has been developed based on the combination of a proton exchange membrane (PEM) electrolysis cell and a fuel cell. As the PEM, NafionTM and laboratory-synthesized sulfonated poly(ether ether ketone) membranes modified with an additional graphene layer in order to enhance the tritium separation factor were used. Both differences in the kinetics of the hydrogen evolution reaction and transport through the graphene layer of different isotopes are the driving factors expected to affect the separation of hydrogen isotopes. The separation factor was measured both during the electrolysis and fuel cell stage using different membranes. The facilitating effect of the graphene on the separation efficiency was determined during the study. The separation factor obtained by the proposed method was evidently higher than that obtained by other conventional methods.

Pore-scale simulation of oxygen transport in a proton exchange membrane electrolysis cell: Effect of the hydrophilia of porous transport layer and catalytic layer

Proton exchange membrane water electrolysis (PEMWE) shows great potential in coupling fluctuating renewable energy for hydrogen production. In PEMWE, the counter-current transport of oxygen in the porous transport layer (PTL) limits the process of water reaching the catalyst layer (CL), significantly affecting the performance and stability of PEMWE. Herein, a lattice Boltzmann model coupled with a reaction boundary is proposed to consider the mechanism of oxygen expelling due to increased pressure. The model is adopted to study the influence of PTL and CL hydrophilia on the mechanism and pattern of oxygen transport. The results suggest that the PTL hydrophilia results in three different flow patterns before the oxygen breakthrough occurs. After the oxygen breakthrough, the extent of oxygen retreatment is also affected by PTL hydrophilia. Increasing PTL hydrophilia can reduce the oxygen saturation within the PTL, but may increase the saturation on the CL surface. A significant decrease in oxygen saturation at the CL surface can be achieved by increasing the hydrophilia of the CL, and even a minor increase in hydrophilia from 74.5° to 54.9° can lead to a reduction of up to 50 % in oxygen saturation. These findings have implications for rationally designing PTL structures.

Measurement and simulation of voltage differences under ribs and channels and temperature variations within channels in PEMEC

The internal voltage inhomogeneity in a proton exchange membrane electrolyzer cell (PEMEC) is experimentally investigated by using customized gaskets. Three miniature thermocouples are strategically placed inside the channels, specifically in the inlet region, middle region, and outlet region, to monitor temperature variations along the channels. Local voltage measurements are conducted in 13 regions corresponding to the flow channels and 12 regions corresponding to the ribs, under various operating conditions. Additionally, a three-dimensional simulation is performed to analyze the underlying causes of non-uniform voltage distribution and temperature variation. The results reveal contrasting trends in temperature changes along the flow direction, attributable to the varying magnitudes of heat loss and electrochemical heat at different current densities. At low current densities, temperatures increase from the inlet to the outlet along the channels, while at high current densities, temperatures decrease in the same direction. Furthermore, the local voltages of the flow channels (Vchan) and the ribs (Vrib) exhibit different increases along the flow direction at various current densities with the Vchan consistently smaller than Vrib. The inhomogeneity of Vchan is found to be greater than that of Vrib due to bubble disturbances in the channels. The proposed measurement principle for local voltage distribution in PEMECs provides insights into the performance discrepancies between the channel and rib scales in the flow field, thereby enhancing our understanding of electrical property inhomogeneity within the cell.

An Experimental Investigation of Hydrogen Production through Biomass Electrolysis

This work investigated hydrogen production from biomass feedstocks (i.e., glucose, starch, lignin and cellulose) using a 100 mL h-type proton exchange membrane electrolysis cell. Biomass electrolysis is a promising process for hydrogen production, although low in technology readiness level, but with a series of recognised advantages: (i) lower-temperature conditions (compared to thermochemical processes), (ii) minimal energy consumption and low-cost post-production, (iii) potential to synthesise high-volume H2 and (iv) smaller carbon footprint compared to thermochemical processes. A Lewis acid (FeCl3) was employed as a charge carrier and redox medium to aid in the depolymerisation/oxidation of biomass components. A comprehensive analysis was conducted, measuring the H2 and CO2 emission volume and performing electrochemical analysis (i.e., linear sweep voltammetry and chronoamperometry) to better understand the process. For the first time, the influence of temperature on current density and H2 evolution was studied at temperatures ranging from ambient temperature (i.e., 19 °C) to 80 °C. The highest H2 volume was 12.1 mL, which was produced by FeCl3-mediated electrolysis of glucose at ambient temperature, which was up to two times higher than starch, lignin and cellulose at 1.20 V. Of the substrates examined, glucose also showed a maximum power-to-H2-yield ratio of 30.99 kWh/kg. The results showed that hydrogen can be produced from biomass feedstock at ambient temperature when a Lewis acid (FeCl3) is employed and with a higher yield rate and a lower electricity consumption compared to water electrolysis.

Operando analysis of in-plane heterogeneity for the PEM electrolyzer cell: Mappings of temperature and current density

The internal multi-physical fields of a proton exchange membrane electrolyzer cell (PEMEC) are affected by various factors, exhibiting an intricate coupling state. During electrolysis process, the complexity manifests as heterogeneous distribution of in-plane temperature and current density, potentially leading to local hot spots and performance degradation. Such challenges pose threats to the lifespan and operational safety of PEMEC. This study developed temperature measurement endplates and segmented printed circuit board (PCB), enabling operando measurement of in-plane temperature and current density distribution inside a 25 cm2 lab-scale PEMEC. The mappings of temperature and current density were plotted, and the in-plane heterogeneity was assessed by the introduced indexes. The results indicate that variations in operational parameters affect the balance among cell heat production, heat dissipation, and heat input in the flow area, leading to temperature distribution heterogeneity. The migration mechanism of high-temperature zone is elucidated. Factors such as water-gas flow and local conduction contribute to the heterogeneity in current density distribution. Additionally, specific operating conditions including cold and warm start-up, and water starvation are taken as cases, and a detailed analysis is conducted on the dynamic behaviors of current and temperature distribution and the heterogeneity evolution. This work not only provides experimental evidence for the electrical-thermal characteristics inside the PEMEC but also offers insights for local performance evaluation and operation fault diagnosis in practical applications.

Development of Novel Coating on Metallic Bipolar Plates for Proton Exchange Membrane Water Electrolyzer Application

Considering the demand for a more environmentally friendly system, renewable and sustainable energy sources, such as wind and solar power are regarded as a promising substitute for fossil fuels in the generation of electricity. Since these energy sources exhibit intermittency and unpredictability, there is a need to develop a highly efficient and rapidly responsive energy conversion system for the purpose of storing this energy as a chemical fuel. Due to their ability to manage the variability of intermittent energy sources, proton exchange membrane electrolyzer cells (PEMECs) are garnering considerable interest. However, their broad commercial adoption is hindered by their relatively modest performance and elevated costs. PEM electrolysis is a promising technology for generating substantial quantities of hydrogen from surplus electricity generated by renewable sources. Nonetheless, the expense of the electrolyzer stack arises primarily from the metallic bipolar plates, because it possesses heavy weight and expensive precious metal coatings. Significant efforts have been performed on the development of titanium-based bipolar plates, but it has high base material and fabrication cost. In recent years, there has been a substantial focus on stainless steel bipolar plates for PEM electrolyzer application. Stainless steel can serve as an alternative, but it requires a coating to enhance its anti-corrosion properties. Electroplated chromium coatings exhibit favorable mechanical characteristics and find extensive application in precision mechanical components such as molds and surgical instruments. Their outstanding wear resistance, high hardness, impressive corrosion resistance, and glossy finish make them appropriate for many other applications, including both decorative and functional coatings. As a result, chromium electroplating has emerged as one of the most extensively employed techniques within the electroplating sector. The dense pack chromium layer is prepared on a 316L stainless steel substrate to enhance the anti-corrosion property and electronic conductivity.Herein, the role of gold striking underlayer, and thick chromium coating is studied for preparing the anti-corrosive stainless steel bipolar plates. First, a gold striking film as an underlayer on the stainless-steel substrate is electroplated to passivate the chromium-based oxides. Further, a thick and dense chromium layer is deposited on the gold underlayer by electroplating. The electroplating bath is operated using platinized titanium felt as an anode and 316L stainless steel as a working electrode without the separation of anodic and cathodic compartments. The electroplating solution is consisting of Cr (VI) oxide and H2SO4 (pH = 2). The nanocrystalline chromium coating with a thickness of approximately 2 µm is bright and uniform. Furthermore, gold as a protective layer of thickness approximately 1 µm is coated by electroplating on the chromium surface. The Cr and Au/Cr coatings are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron microscopy (XPS) analysis. Subsequently, the protective layer-coated substrates were analyzed in a simulated PEM electrolyzer environment, and these coatings facilitated promising protective properties on the stainless-steel substrate. The corrosion testing was carried out in 0.5 M H2SO4 + 2 ppm HF solution at 70 0C purged with oxygen. The stable passive film and high corrosion resistance were obtained by gold striking underlayer and chromizing the 316L stainless steel substrate. As a result, the potentiodynamic polarization analysis showed the corrosion current density of 0.84 µA/cm2 for the Au/Cr-Au underlayer sample in a simulated operating environment. In contrast, the absence of the gold striking underlayer between Cr and stainless steel causes the pitting corrosion. The Au/Cr coating is tested in an acidic corrosion media for a long duration of 24 hours and it showed lower degradation as compared to without gold striking underlayer and without Cr film. The findings presented in this study illustrate the feasibility of employing stainless steel as the foundational material for the bipolar plate of a PEM electrolyzer.

Optimization of power allocation for the multi-stack PEMEC system considering energy efficiency and degradation

With the large-scale application of the proton exchange membrane electrolysis cell (PEMEC), the power allocation of the multi-stack PEMEC system has attracted ever-growing attention. However, fluctuating power significantly affects the lifetime and energy efficiency of the system. In this work, a power allocation strategy of the system is proposed based on detailed modeling and characteristics analysis. A complete model of PEMEC is developed considering bubble coverage for research of operating characteristics. To analyze the energy efficiency characteristics of the system, a power model of the PEMEC stack is established. A mathematical method to real-time obtain the frontier of optimal energy efficiency of stacks is also proposed. The degradation model of the proton exchange membrane is developed to determine the safe operation boundary. And then considering the operating status, voltage degradation is introduced to characterize the degradation of PEMEC dynamically. Finally, a power allocation strategy is proposed considering the system's energy efficiency and degradation. Furthermore, a composite revenue function is presented to compare the performance of different power allocation strategies. The results show that the system has the highest consolidated revenue under the proposed strategy. Current work is conducive to the popularization and generalization of the multi-stack PEMEC system.

Study of optimization and prediction methods for PEMEC performance considering the effects of multiple operating parameters

The influence of operating parameters on the hydrogen production performance of the proton exchange membrane electrolysis cell (PEMEC) is crucial. In this paper, we first investigate the effect of a single operating parameter on the performance of PEMEC, and find the law of single operation effect. After that, the orthogonal experimental methods are used to investigate the effect of cross-coupling of combined operating parameters on the performance of PEMEC and the optimal combination of levels of operating parameters is obtained. Finally, the LSTM neural network is used to predict the PEMEC performance under the multiple operating parameters. The results showed that the weights of voltage, temperature, water flow rate, and bolt torque on PEMEC performance were 68.72 %, 20.63 %, 6.17 %, and 4.48 %, respectively. The optimal combination of operating parameters for the experiment is a torque of 3.5 N m, temperature of 70 °C, voltage of 2.0 V, and the water flow rate of 40 mL/min. It is also found that the long short term mermory (LSTM) neural network is able to predict the performance of PEMEC well, and that the experimental data-driven approach is an effective method for predicting the experimental performance.

Investigation of the degradation of proton exchange membrane water electrolysis cells using electrochemical impedance spectroscopy with distribution of relaxation times analysis

Reduction of catalyst loading on Proton Exchange Membrane (PEM) Electrolysis Cells (EC) is needed because of scarcity and high price of the catalyst. Monitoring the degradation of these cells is important to be able to allocate the different processes taking place. Electrochemical Impedance Spectroscopy (EIS) might be suitable for this purpose, but in its usual implementation, the system and the contribution of its components to the total resistance must be already known to build a suitable equivalent circuit model (ECM). Furthermore, the overlap of different processes in the Nyquist and Bode plots hinders the identification of single components of the system. The Distribution of Relaxation Times (DRT) analysis converts the EIS data into a distribution of time constants of individual processes. The contribution of each component to the full cell resistance can be identified by varying different operation parameters. In this work, a PEMEC with low iridium loading was analyzed by DRT and the faradaic processes were identified. A long-term test was carried out and the degradation of the cell was investigated by DRT analysis, to determine the components and processes which limit the cell performance.

Anode and cathode overpotentials under accelerated stress testing of a PEM electrolysis cell

An in-situ reference electrode was used under accelerated stress testing of a proton exchange membrane electrolysis cell. The reference electrode enabled the measurement of anodic and cathodic overpotentials. The accelerated stress test (dynamic load degradation) was conducted for over 1000 h, and it included half-cell measurements of the known anode and cathode potentials, repeated polarization curves, electron impedance spectroscopy and nano-scale imaging.The experiment had an average full-cell degradation rate of 77 μV/h. The anodic overpotential appears to be the main driver of the full-cell efficiency loss. The cathode EIS measurements indicate catalyst layer degradation despite minimal effect on the full-cell performance. The anodic EIS measurements yielded a resistance double that observed at the cathode. By simultaneously analyzing high frequency resistance, corrected half-cell polarization curves and half-cell EIS measurements, half-cell overpotentials can be attributed with greater confidence.

Optimization assessment and performance analysis of an ingenious hybrid parabolic trough collector: A machine learning approach

Parabolic Trough Collector (PTC) is a solar unit that can convert solar radiation into thermal energy at moderate efficiency. Researchers attempted to increase the output of the PTC units by implementing multiple methods including using helical inserts, transparent aerogel, and reflective mirrors. Nevertheless, the output of this system still is not high enough. The proficiency of the PTC unit can improve by integrating it with Thermoelectric Generator (TEG) and Proton Exchange Membrane (PEM) electrolysis cell, which is studied in the current paper for the first time. In the present study, the efficiency in both PTC-TEG and PTC layouts are poked to demonstrate the consequence of the TEG on the denoted unit efficiency. Besides, the sensitivity study is carried out to assess the influence of operating parameters. Also, extensive data collection is generated and employed to train the designed machine learning models to anticipate the performance of the units in countless operating conditions. Based on the results, the highest accuracy in predicting the performance of the units belongs to the adaptive network-based fuzzy inference system. Also, the results show that the highest entropy generation rate for the PTC and PTC-TEG-PEM units is approximately 11.0 W/m.K and 16.9 W/m.K, respectively. In addition, the highest hydrogen production rate of the PTC-TEG-PEM unit is around 21 mol/h; in fact, the electrical input of the PEM electrolyzer is maintained by the TEG module, which its electrical efficiency calculated to be 3%.

3D structured liquid/gas diffusion layers with flow enhanced microchannels for proton exchange membrane electrolyzers

Porous transport layers (PTLs) work as key water/gas transport components in proton exchange membrane electrolyzer cells. In PTLs, the gas accumulation under the lands of bipolar plate (BP) has been widely recognized, which decreases the local water saturation and blocks some active areas. Especially for some 2D structured PTLs, the absence of in-plane transport ability raises transport concerns at high current densities. In this study, a wet etching method is introduced to fabricate 3D-structured PTLs, named flow enhanced liquid/gas diffusion layer (FELGDL) for promoting multiphase transport under BP lands. In-situ performance evaluation validates a 330-mV voltage drop and a 7.9% efficiency improvement at 6 A/cm2 compared with the 2D-structured LGDL, which are mainly attributed to the improved reactant supply to the pores under BP lands. Additionally, the mass transport limitation is extended from 6.3 to 9.0 A/cm2 with an anode water flow rate of 20 mL/min. By the in-situ visualization method, the enhanced in-plane mass transport under BP lands is directly visualized. The successful fabrication and performance validation of FELGDL opened a new direction to high-performance 3D structured PTL manufacturing.

Ionomer-free nanoporous iridium nanosheet electrodes with boosted performance and catalyst utilization for high-efficiency water electrolyzers

Increasing the catalyst utilization efficiency and simplifying electrode fabrication processes are crucial to accelerate development of low-cost proton exchange membrane electrolyzer cells (PEMECs). Here, we develop a facile route to fabricate ionomer-free iridium nanosheet integrated electrodes, in which nanoporous iridium nanosheets (IrNS) with abundant exposed edges and nanopores are deposited on thin titanium liquid/gas diffusion layers (TT-LGDLs) via a low-temperature chemical synthesis strategy. Benefiting from high catalytic activity, good electrode conductivity and excellent liquid/gas transport properties, such nanoporous IrNS electrodes with low catalyst loadings require low cell voltages of 1.65 V and 1.78 V at 3000 and 6000 mA/cm2, respectively. More impressively, a stable performance can be well maintained under extremely high current density tests of 5000 mA/cm2, demonstrating the potential of low-loading nanoporous IrNS electrodes in solid-electrolyte based electrochemical conversion cells that require high current density operation.

On the role of inductive loops at low frequencies in PEM electrolysis

Inductive loops at low frequencies have been observed in the electrochemical impedance spectra (EIS) of various electrochemical cells. Although different physicochemical models for this phenomenon have been suggested in many other applications, this topic has not been widely discussed in the field of proton exchange membrane (PEM) electrolysis.In this article, low-frequency inductive loops in PEM electrolysis cells and their impact on cell performance are analyzed. We show that this phenomenon is reproducible and occurs with different cell materials and setups. Its impact increases with increasing current density and decreasing temperature. At extreme conditions (7 A∙cm−2, 40 °C) we show that the negative polarization resistance of the inductive process can exceed the capacitive polarization processes by a factor of three, resulting in a direct current resistance less than the high frequency series resistance of the cell.

Modelling of a Proton-Exchange Membrane Electrolysis Cell with Liquid-Fed Cathode

Conventional proton-exchange membrane (PEM) water electrolysers use much thicker membranes (>175 µm) than their PEM fuel cell counterparts (<25 µm), which reduces hydrogen crossover but also reduces electrolyzer efficiency due to the increased Ohmic resistance1. Reduction of hydrogen crossover is critical in conventional systems to avoid buildup of hydrogen in the anode above the lower explosive limit. Due to the use of liquid water at the anode in conventional systems, the anode cannot be flushed with air or an inert gas to reduce the hydrogen concentration.If the liquid water supply is moved to the cathode, the anode can be easily purged with air, reducing the safety concern related to hydrogen crossover. Proof-of-concept experiments2 have demonstrated the viability of this approach, but many open questions remain regarding the interplay between water transport, water consumption, membrane hydration, and cell performance, as well as understanding what components and properties are most important in improving the efficiency of such a device.In this work, a framework for modelling of PEM electrolysis cells will be outlined, with special attention to wet and dry anode conditions. The model will be used to provide guidance for optimizing system performance while contributing to understanding of local processes inside an electrolysis cell such as water transport, heat generation, reaction distribution, and bubble formation. We study the impact of various design and operational choices, such as membrane thicknesses, PTL structure, air feed humidity, and differential pressure operation, on the rate of water transport from cathode to anode and on overall cell polarization performance. Using these results, we provide design recommendations for PEM electrolysers with liquid-fed cathodes. Finally, progress towards an open-source implementation of this model will be discussed.This work has been performed within the HOPE (Revolutionizing Green Hydrogen Production with Next Generation PEM Water Electrolyser Electrodes) and HYSTACK (Low cost, high efficiency PEM electrolyser stack) projects financially supported by the Research Council of Norway under project numbers 325873 and 321466, respectively. Ayers, K. et al. Perspectives on Low-Temperature Electrolysis and Potential for Renewable Hydrogen at Scale. Annu. Rev. Chem. Biomol. Eng. 10, 219–239 (2019).Barnett, A. O. & Thomassen, M. S. Method for producing hydrogen in a PEM water electrolyser system, PEM water electrolyser cell, stack and system. Patent No.: WO 2019/009732. EP3649276B1. US11408081B2.

Performance analysis of PEMEC with non-uniform deformation based on a comprehensive numerical framework coupling image recognition and CFD

Proton exchange membrane electrolysis cell (PEMEC) is widely regarded as an efficient device for producing green hydrogen. Proper clamping pressure during cell assembly can reduce contact resistance while ensuring sealing and safety. Meanwhile, the clamping pressure will cause deformation of the cell components, resulting in increasing mass transfer resistance. However, the evolution law of multi-physical parameters under different clamping pressures has not been fully studied. In this study, a comprehensive numerical framework is proposed for non-uniform deformation and performance analysis of PEMEC. The framework includes three parts: non-uniform deformation model, data transmission based on image recognition, and three-dimensional (3D) multi-phase and multi-physical model. The effects of cell component non-uniform deformation on heat and mass transfer, and electrochemical characteristics are studied. The purity of hydrogen production is also fully taken into consideration. Results show that high clamping pressure causes severe deformation of liquid and gas diffusion layers under the land and a significant decrease in porosity and permeability. In addition, the accumulation of oxygen in the flow channel will weaken the liquid water supply rate and form a high oxygen covered region on the membrane. The current density inhomogeneity in this region will increase significantly with clamping pressure. Although high clamping pressure can obtain low contact resistance and high output hydrogen molar fraction, it also increases mass transfer resistance. An appropriate clamping pressure of 3 MPa is recommended with a lower cell voltage of 2.12 V at 2A/cm2 after considering the physical and chemical properties. The present study can provide helpful guidelines on the design of large-scale electrolyzers.