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In order to study the effects of temperature and humidity on the performance of proton exchange membrane fuel cell (PEMFC), a temperature and relative humidity-current (TRH-C) model was proposed. The model took the water flow and membrane water content of anode and cathode flow channels into consideration, and revealed the law of current density distribution and membrane water content distribution under the condition of current step change. According to the real flow channel configuration of the experimental single cell, a simplified PEMFC geometric model was established and the calculation grid was divided, and the TRH-C model was coupled to the multi-physical field calculation software COMSOL. A PEMFC test platform was established to test PEMFC under different temperature and humidity conditions. The operating temperatures of PEMFC were 65 °C and 70 °C, and the inlet humidities were 50% and 75%. The polarization curve, the membrane current density, and the membrane water content under different working conditions were analyzed and discussed. The results show that the TRH-C model can accurately predict the output performance of PEMFC. When the operating temperature is 70 °C, the inlet humidity is 50%, and the current density is 0. 018 A/cm², the relative errors of the TRH-C model of voltage and power density both reach the maximum value, which are 7.306% and 8.837%, respectively. The performance of PEMFC can be improved by increasing operating temperature and inlet air humidity. As the operating temperature increases, the distribution uniformity of membrane current density fluctuates and the mem-brane water content decreases. With the increase of inlet air humidity, the film current density distribution becomes more uniform and the film water content increases. This work provides a new theoretical method for optimizing inlet air strategy control and improving the output performance. [ABSTRACT FROM AUTHOR]

Hydrogen-powered polymer electrolyte membrane fuel cells (PEMFCs) show promising potential to power a wide range of mobile and stationary applications and to reduce greenhouse gas emissions significantly. In PEMFCs, the oxygen transport and the water transport are essential for a long lifetime and high-performance characteristics. The diffusion media (DM), located between the bipolar plate and the catalyst-coated membrane, is a crucial component of the fuel cell that significantly affects the cell-internal processes. Usually, the DM is a two-layer material system consisting of a microporous layer based on carbon black particles coated onto a porous gas diffusion layer (e.g., carbon paper). The properties of the microporous layer regarding the water transport at high current densities and, consequently, the fuel cell's performance and lifetime can be improved by laser structuring. Within this work, different microporous layers with varying binder content and porosities were structured by locally ablating the material using ultrashort-pulsed laser radiation in the infrared wavelength range. The effect of varying process parameters was additionally investigated. Furthermore, the ablation efficiencies were calculated for increasing pulse repetition rates to qualify a process window for an industrial structuring process. The size of the micro-drillings and the heat-affected zone surrounding the hole were evaluated through topographic and microstructure analyses using a laser scanning microscope and a scanning electron microscope with energy-dispersive x-ray spectroscopy. The results showed a rather small influence of the porosity and composition of the microporous layer on the ablation behavior. In contrast, the laser structuring parameters influenced the micro-drilling geometry significantly. [ABSTRACT FROM AUTHOR]

The ultra-high-speed electric air compressor (UHSEAC) is affected by the electromagnetic torque components of the ultra-high-speed permanent magnet synchronous motor (UHSPMSM) during wide-range speed regulation, resulting in intense speed fluctuation. Electromagnetic torque components are generated by the effects of permanent magnet field harmonics, stator slotting, and current harmonics. It is very important to conduct simulation comparisons and theoretical descriptions of different sources of pulsation factors. In this paper, firstly, the electromagnetic torque model of UHSPMSM with a rated speed of 80,000 rpm is constructed and verified by an experimental bench. Secondly, the electromagnetic torque components of UHSPMSM are extracted on the basis of the electromagnetic torque model. Finally, the electromagnetic torque components' characteristic law is investigated under different ultra-high-speed operating conditions. The results show that under ultra-high-speed operation, the frequency and amplitude of electromagnetic torque components become larger with increasing speed. And the amplitude of electromagnetic torque components becomes larger with increasing torque. This paper constructs the observation object of the high-frequency state observer and does the preliminaries for the design of the UHSEAC controller. [ABSTRACT FROM AUTHOR]

Direct borohydride fuel cell (DBFC) as a direct alkaline liquid fuel has some benefits over other gaseous fuel cells because of great theoretical voltage, power density, energy density, environmental friendliness, and fast answer. Also, sodium borohydride (NaBH4) is simply storable, chemically steady, and safe as it is non-flammable. In this work, UiO-66 metal–organic framework (MOF) has been prepared and defined by X-ray diffraction (XRD), nitrogen sorption isotherms, Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), and field emission scanning electronic microscopy (FESEM) techniques. The appearance of sharp peaks in the XRD pattern indicates that there is worthy crystallinity in the organized MOF and there are no impurities. The BET surface area was obtained to be 1253.1 m2 g−1. The modified carbon paste electrode (CPE) by this MOF and nickel hydroxide (Ni(OH)2-UiO-66/CPE) was applied as an effective and simple electrode for electro-oxidation of NaBH4 in the alkaline media. The anodic current of NaBH4 was amplified intensely at the Ni(OH)2-UiO-66/CPE contrary to the bare CPE surface. The influence of modifier amount (UiO-66) in the constructed CPE, the concentration of NaOH and nickel chloride, and the time for Ni(II) loading were considered for NaBH4 electrocatalytic oxidation via response surface methodology. The attained consequences identify that Ni(OH)2-UiO-66/CPE exhibits good electrocatalytic activity for NaBH4 oxidation due to microporous building and great surface area of synthesized UiO-66. The catalytic rate constant was attained to be 1.53 × 103 cm3 mol−1 s−1, and the diffusion coefficient was found to be 1.51 × 10−7 cm2 s−1. The fabricated Ni(OH)2-UiO-66/CPE displayed worthy reproducibility and stability, and it has a small cost and background current and ease of surface regeneration. The Ni(OH)2-UiO-66/CPE has enhanced poisoning tolerance ability than Ni(OH)2/CPE for electrocatalytic oxidation of NaBH4 and is a superior sensor for the extensive duration action. According to the obtained chronoamperograms in 3000 s, it can be confirmed that the Ni-UiO-66/CPE electrode has improved the toxicity tolerance compared to the unmodified CPE and is a superior nanosensor for long-term acquisition. Also, the Ni(OH)2-UiO-66/CPE maintained 91% and 77.9% of its preliminary answer after 14 and 90 days by CV technique, respectively, which proposes that it has good stability. [ABSTRACT FROM AUTHOR]

In order to reveal the effect of purging water during the startup process of fuel cells and optimize the purging strategy, a three-dimensional model and a one-dimensional model for the startup process of proton exchange membrane fuel cells (PEMFCs) were established. The influence of hydrogen flow rate and initial oxygen content was explored. The results show that at the beginning, the anode is filled with oxygen, but when hydrogen gas is introduced, the air is expelled along with the movement of the hydrogen-air interface. Once the anode is filled with hydrogen gas, the hydrogen-air interface disappears. As the flow rate increases, the residual oxygen content decreases more rapidly, and the time required to remove oxygen completely becomes significantly shorter. The higher the initial oxygen content, the longer the purging process takes and the more time is required for purging. As purging progresses, the rate of oxygen removal gradually decreases until it reaches zero. Using a high flow rate followed by a low flow rate for purging yields better purging efficiency, shorter purging time, and lower consumption compared to using a low flow rate followed by a high flow rate for purging. Implementing a stepwise or linear load increase during startup is beneficial for improving the voltage dynamic response and enhancing gas distribution in fuel cells. [ABSTRACT FROM AUTHOR]

Fuel cell systems (FCSs) have been widely used for niche applications in the market. Furthermore, the research community has worked on using FCSs for different sectors, such as transportation, stationary power generation, marine and maritime, aerospace, military and defense, telecommunications, and material handling. The reformation of various fuels, such as methanol, methane, and diesel can be utilized to generate hydrogen for FCSs. This study introduces an advanced convolutional neural network (CNN) model designed to accurately forecast hydrogen yield and carbon monoxide volume percentages during the reformation processes of methane, methanol, and diesel. Moreover, the CNN model has been tailored to accurately estimate methane conversion rates in methane reforming processes. The proposed CNN models are created by combining the 3D-CNN and 2D-CNN models. The Keras Tuner approach in Python is employed in this study to find the ideal values for different hyperparameters such as batch size, learning rate, time steps, and optimization method selection. The accuracy of the proposed CNN model is evaluated by using the root mean square error (RMSE), mean absolute percentage error (MAE), mean absolute error (MAE), and R2. The results indicate that the proposed CNN model is better than other artificial intelligence (AI) techniques and standard CNN for performance estimation of reforming processes of methane, diesel, and methanol. The results also show that the suggested CNN model can be used to accurately estimate critical output parameters for reforming various fuels. The proposed method performs better in CO prediction than the support vector machine (SVM), with an R2 of 0.9989 against 0.9827. This novel methodology not only improves performance estimation for reforming processes but also provides a valuable tool for accurately estimating output parameters across various fuel types. [ABSTRACT FROM AUTHOR]

As the development of hydrogen fuel cell cars moves from concept to mass production, customers need safe, practical, and easy refueling experiences. The performance and lifetime of fuel cell stacks, as well as other operational factors like valve functioning, are greatly influenced by the purity of hydrogen. The advances achieved by earlier researchers in promoting hydrogen as a possible significant fuel source for the future are fully examined in this publication. Hydrogen is an energy carrier that has the potential to replace fossil fuels. It may be used as a fuel source for cars that run on fuel cells as well as internal combustion engines. To minimize aberrant combustion, extra consideration has to be given to engine design when considering hydrogen as a fuel for internal combustion engines. This strategy may result in higher power output, lower nitrogen oxide (NOx) emissions, and enhanced engine efficiency. The research explores the designs of fuel cell cars that use hydrogen by converting it into energy as well as the designs of internal combustion vehicles fueled by hydrogen via combustion. In addition, hybrid variants of these cars are shown for a thorough comprehension of the topic. The article also looks at the structure and future possible benefits of hydrogen fuel cell electric cars in the context of the automotive sector; these topics are covered in a separate section. [ABSTRACT FROM AUTHOR]

Waste heat is one of the major problems associated with the energy system. This paper discusses an energy, exergy, and emissions approach for the hybrid system by utilizing waste heat to the maximum extent. A thermoelectric generator (TEG) is incorporated to utilize the low-temperature waste heat from a hybrid model of a solid oxide fuel cell (SOFC) and a combined heat and power (CHP) system. SOFC is an electrochemical cell that generates power at high temperatures through an electrochemical reaction. The high-temperature, unutilized fuel leaves the SOFC, which is burned in the afterburner. The afterburner temperature controls the operating temperature of SOFC. Here, three recuperators are used to utilize this high-temperature waste heat to improve the performance of SOFC and simultaneously generate heat power from the water or gas recuperator. TEG is an auxiliary power production technology that converts waste heat into energy. A novel integration of TEG with SOFC–CHP hybrid system to utilize the low temperature waste heat, is employed. The main goal of this study is to analyze a novel SOFC–CHP-TEG hybrid system in terms of its thermodynamics and emissions. A Two stage TEG is integrated with the SOFC–CHP hybrid system. The simulation model of high temperature fuel cell (SOFC) is developed on MATLAB and validated with published results. This study analyses the impact of pressure ratio and afterburner temperature on the performance of SOFC–CHP-TEG. To do this, perform energy and exergy assessments using the principles of the first and second laws of thermodynamics. A novel exergy-based sustainability index with emissions analysis for the proposed SOFC–CHP is presented. The achieved overall energy efficiency is 62.54% at a pressure ratio of 12 and an afterburner temperature of 1000 K. With an increase in pressure ratio and temperature, the level of CO emissions reduces significantly. [Display omitted] • A novel energy exergy for SOFC–CHP-TEG system is presented. • Exergy based performance is compared and achieve 56.62. • Utilization of waste heat via TEG. • Energy efficiency of SOFC–CHP-TEG is 62.54% at rp = 12 and afterburner temperature of 900 K. [ABSTRACT FROM AUTHOR]

Among the global carbon emissions in different fields, the carbon emissions in the transportation sector account for more than 1/4. Only the development of passenger car technology makes it difficult to achieve the climate goals. E-bike is considered to be one of the effective solutions. Hydrogen energy, as one of the representatives of new energy, has the advantages of cleanliness, high efficiency, and high energy density. Therefore, in this paper, a long-range hydrogen-electric hybrid bike and its energy management strategy are designed to achieve optimal performance. Herein, two energy management strategies, including the threshold-based and fuzzy logic optimized threshold-based strategy, are designed and compared by evaluating the parameters of equivalent hydrogen consumption, state of charge fluctuation, and the final state of the control system. The results show that with an initial SOC of 50% for Li-ion battery, the fuzzy logic optimized threshold-based strategy reduces equivalent hydrogen consumption by up to 16% compared to the threshold-based strategy. Besides, the fluctuation of the Li-ion battery's state of charge could be reduced by up to 54.7%, indicating that the fuzzy logic optimized threshold-based strategy is a promising energy management strategy for fuel cell hybrid E-bike. [Display omitted] • A long-range hydrogen-electric hybrid E-bike with metal hydride hydrogen storage is designed. • A fuzzy logic optimized threshold-based energy management strategy (EMS) is proposed. • Li-ion battery SOC fluctuations could be reduced by up to 54.7% via fuzzy logic optimized EMS. • Fuzzy logic optimized EMS shows self-adaptability and economic H 2 consumption for hybrid E-bike. [ABSTRACT FROM AUTHOR]

In the contemporary global discourse on environmental and developmental issues, the dual challenges of sustainable green energy and water supply stand paramount. These elements are vitally intertwined with the socio-economic vitality of the world. Notably, regions plagued by freshwater scarcity are increasingly turning to desalination which consists of a reliable and unconventional water source. The intersection of renewable energy with desalination and water purification processes presents a compelling synergy. This approach is particularly pertinent in areas where freshwater shortages coexist with abundant solar energy availability. Additionally, these technologies boast the advantage of low operational and maintenance costs. This paper delves into the design, optimization and financial analysis of a novel, standalone hybrid energy system, integrating photovoltaic and fuel cell technologies, for an agriculture farm situated in Kairouan, Tunisia. Unlike conventional systems, this model foregoes battery storage in favour of hydrogen storage, generated through water electrolysis powered by solar energy. This system harnesses solar energy for direct electrical power generation and hydrogen gas production. A segment of the generated electricity is allocated to electrolysis for green hydrogen production. In times of solar unavailability, the stored hydrogen is reconverted to electricity via a fuel cell. An intriguing aspect of this system is the utilization of saline well water, which, due to its high salt content, necessitates purification through desalination to prevent damage to the electrolysis unit and to render it suitable for agricultural irrigation. [Display omitted] • The production of green hydrogen, water and electricity for agriculture farm in Tunisia is analyzed. • The Levelized cost of green hydrogen produced in the PV farm is 2.25 €/kg. • A PV hydrogen Farm station with a capacity of 140 kW produces 1991 kg of green hydrogen and 235 MW h of electricity yearly. [ABSTRACT FROM AUTHOR]

[Display omitted] • N- and F-doped bimetallic carbides (C 19 Cr 7 Mo 24) are synthesized at 1300 °C. • Both show excellent stability and higher ORR activities than Pt/C. • Electron transfer leads to excellent activity and stability. • F dopant more favors electron transfer than the N dopant. • Bimetallic carbide more favors electron transfer than monometallic carbide. Nitrogen- and fluorine-doped bimetallic carbide composites with graphite matrix (abbreviated as C 19 Cr 7 Mo 24 /NG and C 19 Cr 7 Mo 24 /FG) are synthesized through carbonization at 1300 °C. The C 19 Cr 7 Mo 24 /NG displays an initial half-wave potential (E 1/2) of 0.873 V and suffers merely 3 mV decrease in E 1/2 within 60,000 CV cycles for oxygen reduction reaction (ORR) in alkaline media. A H 2 /O 2 fuel cell testing system using the C 19 Cr 7 Mo 24 /NG as cathode maintains 95.9% of the initial peak power density (1.08 W cm−2) within 60,000 cycles. The C 19 Cr 7 Mo 24 /FG shows higher ORR activity than the C 19 Cr 7 Mo 24 /NG. The positive and negative charge centers caused by the N or F dopants are the critical reasons to their high activities. While F and bimetallic carbide more favor electron transfer respectively than the N and monometallic carbide. Their excellent stabilities originate from interactions among atoms due to electron transfer and the intrinsic chemical inertness of graphite and bimetallic carbides. [ABSTRACT FROM AUTHOR]

The main contribution of this study is the multi-objective size optimization of a standalone hybrid energy system (HES) to supply the electricity demand of a health care center in Kerman province, south of Iran, in which fuel cell, photovoltaic, and diesel generator produces electricity, while the combination of electrolyzer and hydrogen tank is the storage system. The non-dominated sorting genetic algorithm II (NSGA-II) is applied to find the Pareto front of optimal solutions, where the loss of power supply probability (LPSP) and total net present cost (TNPC) are the objective functions. The results show that considering operating reserve and uncertainty, the TNPC increases 30.50% compared to the base load. Moreover, the fuel cell has a smaller share of energy production, which is due to the high cost of the storage system, while about 50% of the demand load is provided by DG in the cold seasons. The sensitivity analysis reveals that TNPC decreases by 8.93% for a 50% reduction of the storage system cost, while increases by 24.55% for a 50% increase in the fuel cost. Moreover, AHP/TOPSIS-based multi-criteria decision-making is implemented to find the best solution according to the opinions of three different managers/experts, which shows that the HES with LPSP = 0.2503% and TNPC = 2.1038 × 106 $ is the best solution in which uncertainties and operating reserve are also considered. • An optimum HES is designed to supply the load demand of a health care center. • Multi-objective size optimization is applied using NSGA-II based on TNPC and LPSP. • An extensive AHP/TOPSIS-based MCDM is presented to find the best optimal solution. • A comprehensive sensitivity analysis is performed for cost of fuel and storage system. • TNPC changes more with the cost of the storage system than the cost of the fuel. [ABSTRACT FROM AUTHOR]

Poly-ether-ether-ketone (PEEK), an organic polymer material with good thermal stability and tensile strength, has been regarded as an ideal material for anion-exchange membrane (AEM). Metal-organic framework materials (MOFs) possess excellent chemical stability and mechanical properties. In this work, MOF-801 was impregnated with ionic liquid and the obtained IL@MOF-801 was introduced into imidazole-functionalized PEEK to obtain IL@MOF/Im-PEEK composite anion exchange membranes. The addition of IL@MOF-801 not only increases the ion transport channels but also forms hydrogen bonding network with the imidazole groups on PEEK, which is beneficial for improving ion transport properties and mechanical strength. The anion-exchange membrane consisting of 4% IL@MOF-801/Im-PEEK achieved an anionic conductivity of 116.8 mS/cm at 80 °C and 100% RH and excellent mechanical properties with a tensile strength of up to 208.7 MPa. [Display omitted] • Ionic liquid was impregnated in MOF-801 to obtain IL@MOF-801 with low leakage rate. • IL@MOFs construct new ion channels to improve the ionic conductivity of the membrane. • The combination of PEEK and MOFs produces a composite membrane with high tensile strength. [ABSTRACT FROM AUTHOR]

As the global shipping industry experiences rapid expansion, the imperative to address greenhouse gas emissions and environmental impact becomes increasingly paramount. Hydrogen has emerged as a pivotal and eco-friendly energy source, offering a pathway towards carbon neutrality and a complete zero-carbon transition in maritime operations. However, the widespread adoption of hydrogen-powered ships hinges on the establishment of robust regulations and technical standards. This paper conducts a comprehensive examination of hydrogen fuel cell (FC) technology in ships, scrutinizing the role of international classification societies and exploring existing standards and regulations within the maritime industry, specifically centered around hydrogen energy. The study outlines a strategic developmental roadmap for a green shipping hydrogen energy system tailored for hydrogen FC-powered ships in China. Emphasizing the differences in hydrogen application between fuel cell vehicles and ships, the paper elucidates technical challenges unique to hydrogen FC-powered ships. Furthermore, it proposes a visionary framework for future technical standards, advocating for the creation of a ship-based hydrogen energy standard system, the development of core technical standards, and a heightened focus on safety regulations. Through comprehensive analysis and compelling argumentation on hydrogen fuel cell ship technology and standards, this paper underscores the indispensable role that technical standards play in propelling the advancement of environmentally friendly shipping. Beyond serving as an informative resource, the paper aims to provide valuable guidance and direction for the future demonstration, application, and promotion of hydrogen fuel cell ship technology. Ultimately, it underscores the pivotal role of technical standards in advancing sustainable maritime transportation. • Analyze hydrogen energy technical standards from the production, storage, safety. • Comparison of hydrogen energy technical differences between vehicles and ships. • Outline the unique challenges of applying hydrogen technology to ship operations. • Constructed a technical standard framework for future hydrogen energy ships. [ABSTRACT FROM AUTHOR]

Traditional flow fields and gas diffusion layers (GDL) suffer from water flooding at the rib contact surface, resulting in mass transfer obstruction. Herein, an integrated component (i‐component) with tri‐part of the flow field, gas diffusion backing, and the microporous layer is prepared using the filter molding method to prevent flooding at the rib. The i‐component with micro‐tunnels is more compact than traditional fuel cells and has no distinct interface, significantly enhancing fuel cell performance, reducing mass transfer resistance, and improving water management. Remarkably, the mass transfer resistance of the i‐components is reduced by six times, accompanied by a 50% increase in power density (1.63 W cm−2) and a 146% surge in volume‐specific power (24 500 W L−1). Additionally, it exhibits excellent humidity tolerance in the relative humidity range of 30–100%. This method achieves large‐area i‐component (388 cm2) preparation in 0.5 h at 350 °C, which reduces time by dozens and energy consumption by over 100 times compared to the traditional method for preparing commercial GDL. The i‐component significantly enhances the mass transfer and water management capabilities of fuel cells. Hence, the i‐component provides new strategies for next‐generation fuel cells, water electrolysis, flow battery, carbon dioxide reduction, etc. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell electric vehicles (HFCEVs) are gaining revived attention due to the HFCEVs promising potential as important syndicates to net zero carbon emission attainment. However, HFCEVs' performance and cost-effectiveness do not yet match up with battery electric vehicles (BEVs) and traditional fossil fuel vehicles despite many different Energy Management System (EMS) strategies previously adopted. Rule-based controls are still limited specifically in handling multi-objective systems as HFCEVs and some optimization-based algorithms also pose computational and retrofitting difficulties. Therefore, this study presents the prospect of artificial intelligence-based algorithms, control systems, and energy management strategies advances on HFCEVs performance optimization. EMS strategies; AI-based algorithms categories, functions and hybridization; the state-of-art and future direction of AI-based algorithms and HFCEVs' cost components amongst others are explained in the study. The multi-objective-based algorithm, reinforcement learning algorithm, and different hybridizations are enhancing HFCEVs cost-competing edge. • Fuel cells have higher energy density and 3.5 lighter than lithium-ion batteries. • Reinforcement learning algorithms are highly effective for real-time optimization. • Digital twin and inverse reinforcement learning algorithms need further adaptations. • HFCEV has 3–4 times lower fuel consumption than IC-engine per km in urban driving. [ABSTRACT FROM AUTHOR]

Increasing greenhouse gas emissions and the increase in renewable energy sources in electricity generation have led to an increasing interest in hydrogen in recent years. As an energy storage solution for renewable energy, hydrogen can contribute to decarbonizing industries and transportation sectors as well as balancing energy systems. In this paper, the primary objective is to examine different methods for producing hydrogen depending on the primary energy source. In addition, it evaluates the economic and environmental performance of three types of hydrogen, known as hydrogen colors, and the significant obstacles to widespread fuel cell adoption. The key finding is that hydrogen's environmental benefits depend heavily on how hydrogen is produced and what fuel is used to produce it. Green hydrogen can only be produced using wind, solar photovoltaic (PV), and hydroelectric power. The emissions from other sources, such as blue hydrogen that uses carbon capture, utilization, and storage (CCUS) or electrolysis using electricity from the grid, are significantly higher than those from grey hydrogen. Furthermore, establishing an international hydrogen market will reduce costs and allow hydrogen to be produced in optimal locations. Lastly, a key unresolved question is whether hydrogen, whatever its color, is economically competitive in any sector of the energy system, despite all external costs associated with it. A policy framework that supports technological advancements, cost reductions, and future priorities will determine hydrogen's success in the future. The transition from grey hydrogen to green hydrogen should be facilitated by this framework. [ABSTRACT FROM AUTHOR]

To improve the conductivity and flexural strength of bipolar plates for proton-exchange membrane fuel cells, multi-filler-reinforced composites were prepared using graphite, multiwalled carbon nanotubes (MWCNTs), chopped carbon fibers (CCFs), and phenolic resin (PF). The effects of CCF content (0–6 wt.%) and MWCNT content (0–8 wt.%) on the flexural strength, electrical conductivity, interfacial contact resistance (ICR), density, hydrophobicity, and corrosion behavior of the composites were investigated. Results showed that the addition of a small number of CCFs (≤4 wt.%) effectively improved the flexural strength but slightly reduced the electrical conductivity and increased the ICR of the graphite/PF/CCF composites. Further addition of MWCNTs (≤6 wt.%) significantly improved the electrical conductivity and ICR of the graphite/PF/CCF/MWCNT composites, while maintaining high flexural strength. When the composites were filled with 4 wt.% CCFs and 2 wt.% MWCNTs, their electrical conductivity, flexural strength, ICR under 1.38 MPa, and contact angle were 272.8 S/cm, 43.1 MPa, 1.19 mΩ·cm2, and 101.5°, respectively. Compared to unreinforced composites, the electrical conductivity was reduced by 27.2%, the flexural strength was increased by 65.1%, and the composite possessed favorable hydrophobicity as well as corrosion behavior. This work reveals that CCFs and MWCNTs can effectively cooperate to improve composites' electrical and flexural strength properties. [ABSTRACT FROM AUTHOR]

In this study, the electro-oxidation reaction of ethanol over Pd–Cu supported on Cu porphyrin (TPPCu) was investigated. The catalyst was synthesized using the microwave-assisted polyol method and physicochemically characterized by XRD, XPS, SEM, EDS, TEM, EDAX, UV–Vis, FTIR, and RBS. A Cu-enriched catalyst with Cu3Pd, Pd,Cu, and TPPCu phases was identified using XRD and XPS. However, according to the RBS results, the catalytic surface was enriched with Pd, indicating that the interaction between TPPCu and Pd–Cu allowed the presence of Pd on the surface, thus enhancing the catalytic response of the material. This synthesis prevented the deprotonation of porphyrin on the electrocatalyst, as confirmed by XPS analysis. Electrochemical studies based on cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the response of the catalyst to variations in the scan rate and increasing ethanol concentration. The electrochemical response of PdCu/TPPCu improved with an increasing number of cycles, indicating improved mass transport, thus improving its electrochemical response and tolerance to CO contamination. This catalyst exhibited a high electroactive surface area of 49.4 m2/g, which could be related to the presence of TPPCu as a support. The behavior of the catalyst on the anode of a fuel cell fed with ethanol, bioethanol, and bioethanol residues was evaluated. [ABSTRACT FROM AUTHOR]

This paper presents the design and development of a modular multiport DC-DC converter for hybrid charging station. The system is supplied by renewable energy sources (RES) like solar photovoltaic system (SPV), wind energy system (WE) and fuel cell (FC). The proposed converter has several benefits like current sharing capability, providing lower current ripple and lower voltage ripple, lower current stress on the switches, lower current rating of switches and using a small-sized inductor. Due to the unavailability of continuous flow of power from the RES throughout the day, an effective energy management system using the adaptive neuro-fuzzy inference system (ANFIS) is implemented in the proposed system. ANFIS controller is implemented to identify and enable the available power from the renewable energy sources to feed the base load as well as charge the batteries in the hybrid charging station. The ANFIS controller continuously monitors the power availability for the charging station, thereby feeding minimum power to the base load. The proposed system is simulated and tested using the MATLAB/SIMULINK software, and a prototype of the same has been developed in the laboratory. From the simulation and experimental results, it is observed that the proposed converter suits best for integrating hybrid sources and used for charging the EVs. Improved life expectancy of the battery is obtained using the proposed converter. The proposed converter produces an efficiency of 97% and is superior to the other existing converters. [ABSTRACT FROM AUTHOR]

This work presents the results of manufacturing a single Proton Exchange Membrane Fuel Cell (PEMFC) with Micro-Porous Layers (MPLs) and an active area of 25 cm2, and the experimental study required to build its polarization curve. Based on the physical model data, a numerical model of this PEMFC is created in the ANSYS PEM Fuel Cell module. Numerical simulations were performed with boundary conditions consistent with the experimental conditions on the test station. The calculation and experimental result comparison of the polarization curves for voltages ranging from 0.29 V to 0.94 V proved that the utilized numerical model is highly reliable. The simulation of PEMFC without MPLs was conducted according to such stable input parameters and boundary conditions. The results show that the PEMFC performance decreases significantly due to the flooding phenomenon inside PEMFC without MPLs compared to PEMFC with MPLs. Such phenomena are challenging to observe experimentally. Numerical modeling can be further used to optimize the fuel cell components. [ABSTRACT FROM AUTHOR]

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In this article, the characterization of intermetallic MgAl and the possibility for hydrogen storage in the fuel cells through doping with transition metals including Ni, Pd, Pt, Cu, Ag and Au have been investigated. The importance of the electrical double layer at the interface between a metal and Mg/Al atoms together with its interaction with hydrogen molecule to produce initially electrostatic adsorption are highlighted. The important step in which molecules enable energy storage is production of a physical barrier where a physical adsorbed barrier of molecules prevent movement near the metal surface or decrease in metal reactivity where chemisorbed hydrogen molecule stick to active area on the metal surface. The projected density of state can also estimate a certain charge assembly between (Ni, Pd, Pt, Cu, Ag, Au) and MgAl surface which indicate the complex dominant of metallic features and an exact degree of covalent traits between transitions metals and MgAl surface during H2 adsorption. In the nuclear magnetic resonance spectroscopy, it has been observed the remarkable peaks around metal elements of Ni, Pd, Pt, Cu, Ag, Au through the doping on the MgAl nanoalloy, however there are some fluctuations in the chemical shielding behaviors of isotropic and anisotropy attributes. Furthermore, all accounted amounts are very close, which demonstrate the agreement of the measured specifications by all methodologies and the reliability of the computing values. [ABSTRACT FROM AUTHOR]

Protonated poly (2,20-m-phenylene-5,50-bibenzimidazole) (PBI) membranes are good electrolytes for proton-exchange membrane fuel cells (PEMFC) as they can be operated at high temperatures, thus favoring catalysis reaction kinetics, CO elimination, and water management. Electrolyte production from polymeric membranes with controlled thickness is important for the study of their properties and their use in fuel cells (FCs). When preparing PBI membranes by casting with controlled thickness, polymer solubility in different solvents was assessed as well as the relation between petri dish diameter and solution concentration. Membranes with different thicknesses were phosphonated and had their phosphoric acid (PA) and water uptake measured. A systematic procedure was established to prepare membranes with predetermined thickness using 12 mL of 5-8% PBI in N,N-dimethylacetamide in petri dishes measuring 5-9 cm. Membranes with predicted thickness of 60 ± 20 μm and 200 ± 40 μm showed a maximum water uptake of 8.34 ± 0.01% and PA uptake of 32 ± 1% and 18 ± 2%, respectively. This study contributed significantly to systematize procedures for producing high-quality membranes with predefined thickness and to understand the influence of their thickness on their degree of phosphonation. [ABSTRACT FROM AUTHOR]

Electrolyzers and fuel cells will be crucial for achieving global clean hydrogen and industrial decarbonization goals. However, the nascent clean hydrogen sector faces uncertainties around material supply chains and technology end‐of‐life management. This work aims to guide the transition to a circular hydrogen economy by using process modeling, techno‐economic analysis, and life cycle assessment to evaluate the material cost, energy use, greenhouse gas (GHG) emissions, toxicity, and water use of five potential recycling strategies for proton exchange membrane electrolyzers (PEMWE) and fuel cells (PEMFC). Hydrometallurgy, acid dissolution, and electrochemical dissolution are shown to offer 2–7 times improvement across all assessed metrics relative to the manufacturing of PEMWE and PEMFC from raw materials. Recycling can also lower the raw material demand, material cost, energy use, and GHG emissions associated with PEMWE and PEMFC deployment in the United States in 2050 by 23%, 19%, 21%, and 16%, respectively. This study provides key insights into the costs, benefits, and complexities of recycling strategies for PEMWE and PEMFC, aiding the development of a circular economy that is synergistic with clean hydrogen deployment. [ABSTRACT FROM AUTHOR]

The widespread deployment of fuel cell technology requires the development of new manufacturing technologies to turn it economically viable. Stencil printing is known as one of the highest throughput techniques for applying adhesives, where a moving squeegee forces the adhesive through pre-defined apertures in a stencil onto a substrate. Thus, stencil printing is investigated as an innovative method to reduce production costs and manufacturing cycle times of fuel cell sealings. Moreover, in order to allow a greater design freedom, adhesive layer thicknesses up to 500 µm should be printable under reproducible conditions and within cycle times <3 s, which have not been realized or implemented until today. With the aim of printing closed-loop structures (sealings), a mesh located on the upper region of the aperture needs to be integrated. However, this mesh can produce additional air bubbles and surface irregularities, which might affect the sealing performance and diminish the process stability. This paper describes the experimentally identified formation mechanisms of bubbles during the separation step. The quantity and size of these bubbles were measured for five separation speeds, two mesh opening sizes and three adhesive systems (UV-curable acrylic). Primary focus was placed on relating the print results with the adhesive rheological properties, which are decisive to successfully implement the sealing application process. It was found that a previously derived empirical relationship to predict the adhesive tendency to stretch filaments can be employed as a model to quantitatively assess the characteristics of bubbles that emerge during the separation step and thus specify rheological properties to enhance print quality. [ABSTRACT FROM AUTHOR]

Unconventional approaches to propulsion system design are increasingly being explored to meet increasing demands for efficiency, ecology, and reliability. This paper focuses on the analysis of simulated dynamic loads on the propulsion system of ships that feature unconventional power systems - Reformed Methanol Fuel Cell System (RMFC). The analysis is aimed at understanding the performance of these systems under dynamic sea conditions, assessing their performance, and identifying potential challenges and benefits associated with them (including military ones). According to military assumptions, an undeniable benefit is the minimization of the ship's physical fields and its independence from the base (i.e., in the future, obtaining hydrogen from seawater electrolysis). [ABSTRACT FROM AUTHOR]

Existing research on fault diagnosis for polymer electrolyte membrane fuel cells (PEMFC) has advanced significantly, yet performance is hindered by variations in data distributions and the requirement for extensive fault data. In this study, a cross-domain adaptive health diagnosis method for PEMFC is proposed, integrating the digital twin model and transfer convolutional diagnosis model. A physical-based high-fidelity digital twin model is developed to obtain diverse and high-quality datasets for training diagnosis method. To extract long-term time series features from the data, a temporal convolutional network (TCN) is proposed as a pre-trained diagnosis model for the source domain, with feature extraction layers that can be reused to the transfer learning network. It is demonstrated that the proposed pre-trained model can hold the ability to accurately diagnose the various fuel cell faults, including pressure, drying, flow, and flooding faults, with 99.92 % accuracy, through the effective capture of the long-term dependencies in time series data. Finally, a domain adaptive transfer convolutional network (DATCN) is established to improve the diagnosis accuracy across diverse fuel cells by learning domain-invariant features. The results show that the DATCN model, tested on three different target domain devices with adversarial training using only 10 % normal data, can achieve an average accuracy of 98.5 % (30 % improved over traditional diagnosis models). This proposed method provides an effective solution for accurate cross-domain diagnosis of PEMFC devices, significantly reducing the reliance on extensive fault data.

To accelerate the implementation of zero-emission power installations based on proton-exchange membrane fuel cells, it is necessary to maximize the power characteristics of these devices. For this purpose, we have obtained and tested a new N-doped carbon support and a synthesized Pt/C catalyst based on it with a platinum loading of about 37.3 %. A comparison of the degradation resistance of the initial support and the N-doped one has shown greater stability of the latter. At the same time, Raman spectroscopy has confirmed the presence of the C–N bond, which indicates the successful doping of carbon with nitrogen. The resulting Pt/C catalyst based on an N-doped support is characterized by a substantially narrow size dispersion and an ultra-small nanoparticle size of about 2.6 nm. The high-angle annular dark-field scanning transmission electron microscopy images of the synthesized catalyst have confirmed the presence of individual platinum atoms/clusters uniformly distributed over the surface of the support, and their presence is due to nitrogen embedded into the carbon structure. This material is characterized by a 50 m2 gPt-1 larger electrochemically active surface area and a 227 A gPt-1 greater mass activity compared to the commercial JM40 analog (40 % platinum loading). Meanwhile, the electrochemical parameters remaining after the accelerated stress testing are almost 2 times higher than those of JM40. And the power characteristics in the membrane electrode assembly for the catalyst synthesized by the facile one-pot synthesis method are 13 % (575 mW cm-2) higher than those of the commercial analog (500 mW cm-2). The Pt/C catalyst obtained during the research is deemed promising for commercial use in proton-exchange membrane fuel cells.

Proton exchange membrane (PEM) fuel cells have significant potential for clean power generation, yet challenges remain in enhancing their performance, durability, and cost-effectiveness, particularly concerning metallic bipolar plates, which are pivotal for lightweight compact fuel cell stacks. Protective coatings are commonly employed to combat metallic bipolar plate corrosion and enhance water management within stacks. Conventional methods for predicting coating performance in terms of corrosion resistance involve complex physical-electrochemical modelling and extensive experimentation, with significant time and cost. In this study machine learning techniques are employed to model metallic bipolar plate coating performance, diamond-like-carbon coatings of varying thicknesses deposited on SS316L are considered, and coating performance is evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy. The obtained experimental data is split into two datasets for machine learning modelling: one predicting corrosion current density and another predicting impedance parameters. Machine learning models, including extreme gradient boosting (XGB) and artificial neural networks (ANN), are developed, and optimized to predict coating performance attributes. Data preprocessing and hyperparameter tuning are carried out to enhance model accuracy. Results show that ANN outperforms XGB in predicting corrosion current density, achieving an R2 > 0.98, and accurately predicting impedance parameters with an R2 > 0.99, indicating that the models developed are very promising for accurate prediction of the corrosion performance of coated metallic bipolar plates for PEM fuel cells.

Medium-duty and heavy-duty vehicles (MHDVs) are major contributors to air pollution and greenhouse gas emissions. California leads in transitioning towards zero-emission MHDVs through a comprehensive approach that includes financial incentive s for zero-emission vehicle (ZEV) purchases, improved infrastructure for battery charging and hydrogen refueling, and extensive public awareness campaigns. The state has enacted Advanced Clean Fleets (ACF) regulations, requiring all MHDVs—including box trucks, vans, work trucks, and tractors—to adopt ZEVs between 2035 and 2042. Consequently, thorough analysis and forecasting of market penetration for various MHDVs in the next decade are essential. This study introduces a purchase probability analysis-based dynamic discrete choice (PPADDC) model specifically designed for vehicle choice modeling in the MHDV sector. The model assesses the probabilities linked to sixteen decision factors that influence truck adoption from 2024 to 2040. Utilizing this model, we project market share and penetration under eight scenarios, reflecting our comprehensive understanding of the California market through observational, empirical, and mathematical perspectives. These scenarios differ in terms of vehicle cost, procurement incentives, and infrastructure development strategies. Our findings provide a strategic framework for achieving the ambitious ZEV targets set by the California Air Resources Board (CARB), illustrating that a combination of technological advancements, policy initiatives, and market incentives can significantly enhance ZEV adoption in the MHDV sector. This study not only confirms the practicality of California ZEV goals but also offers valuable insights for policymakers, industry stakeholders, and researchers working towards a more sustainable transportation future.

Abstract The unique properties of solid acid electrolytes, in particular CsH2PO4, are in many ways ideal for fuel cell operation. However, the technology is constrained by high cathode overpotentials. Here a simplified cathode geometry is employed to obtain the fundamental electrochemical parameters (exchange current density and charge transfer coefficient) describing the oxygen reduction reaction (ORR) at the CsH2PO4‐Pt‐gas interface. The parameters are incorporated into a 1D model of the voltage–current characteristics of realistic SAFC cathodes, which reproduced the measured polarization behavior of such cathodes without recourse to fitting adjustable parameters. Following this validation, the model is utilized to evaluate the impact of changes to cathode properties, microstructure, and operating conditions. Of these, the charge transfer coefficient, measured to have a value of ≈0.6 for ORR on Pt in the SAFC cathode environment, is found to have the greatest impact on power output. Nevertheless, even without material modifications, a combination of microstructural and operational modifications are identified with projected performance metrics meeting Department of Energy targets (0.8 V at 300 mA cm−2, and peak power density of 1 W cm−2), albeit at high Pt loadings. However, the analysis indicates that truly meaningful advances will likely necessitate the discovery of alternative ORR catalysts.

In order to improve the internal heat dissipation efficiency of the proton exchange membrane fuel cell, this paper designs and builds a set of fuel cell heat dissipation system experimental bench with a heat dissipation capacity of 15 kW based on the separated heat pipe technology, and investigates the heat dissipation characteristics of the HFE-7100 and ethylene glycol aqueous cooling medium under different condenser processes and different ambient temperatures. The results show that at an ambient temperature of 35 °C, under the same condenser flow arrangement, the two-phase heat dissipation efficiency of HFE-7100 is higher than that of glycol aqueous solution liquid cooling, and its heat dissipation and EER (Energy Efficiency Ratio) are increased by 81.2 %∼98.8 % and 68.2 %∼86.6 %, respectively. The best effect is achieved when the condenser is 3-process, with two-phase heat dissipation of 14.1 kW and EER of 20.5 kW/kW, which are 82.8 % and 68.9 % higher than liquid cooling, respectively. As the ambient temperature rises, the two-phase heat dissipation effect is further improved, and at 50 °C ambient temperature, the heat dissipation is 10.44 kW, which is 145 % higher than that of liquid cooling, and the EER is 15 kW/kW, which is 132 % higher.

The necessity for transitioning to renewable energy sources and the intermittent nature of the natural variables lead to the integration of storage units into these projects. In this research paper, wind turbines and solar modules are combined with pumped hydro storage, batteries, and green hydrogen. Energy management strategies are described for five different scenarios of hybrid renewable energy systems, based on single or hybrid storage technologies. The motivation is driven by grid stability issues and the limited access to fresh water in the Greek islands. A RES-based desalination unit is introduced into the hybrid system for access to low-cost fresh water. The comparison of single and hybrid storage methods, the exploitation of seawater for the simultaneous fulfillment of water for domestic and agricultural purposes, and the evaluation of different energy, economic, and environmental indices are the innovative aspects of this research work. The results show that pumped hydro storage systems can cover the energy and water demand at the minimum possible price, 0.215 EUR/kWh and 1.257 EUR/m3, while hybrid storage technologies provide better results in the loss of load probability, payback period and CO2 emissions. For the pumped hydro–hydrogen hybrid storage system, these values are 21.40%, 10.87 years, and 2297 tn/year, respectively.

The vacuum impregnation resin method was used to prepare composite bipolar plates in fuel cell in this study. The effects of the content of epoxy resin diluent added, temperature and pore structure of graphite on the impregnation content during the vacuum impregnation process were studied. The electrical conductivity, flexural strength and airtightness of the prepared fuel cell bipolar plates were investigated. The results show that increasing the content of diluent and temperature can reduce viscosity and increase the upper limit of resin impregnation, enabling the resin to impregnate and fill into smaller pores, while there are still some pores that cannot be filled and saturated, such as the pores below 0.1 μm are difficult to fully penetrate in the expanded graphite plate, resulting in the resin being unable to completely fill the entire pores of the expanded graphite. The optimal temperature for impregnating the epoxy resin/diluent system by vacuum impregnation is 50 ℃, and the optimal addition ratio of diluent ethylene glycol diglycidyl ether is 15%(mass fraction). The obtained bipolar plate has excellent electrical conductivity of 340.12 S/cm, flexural strength of 41.52 MPa, and helium permeability of 5.4×10-7 cm3·cm-2·s-1.

Abstract Magnesium fuel cells deliver higher electrical power output than lithium-ion batteries and have the potential to become an economically attractive alternative power source for domestic purposes. In place of noble metals in the air cathode of Mg fuel cells, we investigate the use of an integrated structure of a catalyst and current collector composed of a Cu/CuO hetero-structure. For a single cell, comprising of electrodes of dimension 3 cm × 1.5 cm with aqueous NaCl as the electrolyte, the Mg- Cu/CuO-based fuel cell shows an open-circuit voltage of 0.7 V and discharge current drain rate of 0.45 mA/s. A power density of 8.75 µWcm−2 is obtained with a CuO-based cathode when 1 M NaCl electrolyte is used. Relative to the magnesium-carbon-based fuel cell, the Mg-Cu/CuO fuel cell shows improved stability of the anode and cathode materials and extended operational time.

The EU’s energy targets are to achieve at least 32% renewables in the energy mix by 2030. Part of the solution is strengthening consumer rights by empowering individuals to generate their own electricity. The aim of this study was to identify the most suitable energy system for electricity generation of up to 50 kW in the EU residential sector. Multi-Criteria Decision Analysis was used to compare four systems: proton exchange membrane fuel cell with photovoltaic panels, photovoltaic panels, biomass-powered Stirling engine, and solar-powered Stirling engine. Based on the results, the most beneficial system for household electricity generation is the biomass-fueled Stirling engine system due to its affordability, reliability, and low environmental impact. Governments and businesses can use these findings to improve information for the residential sector and enable the transition to renewable energy.

This paper presents an ultra-high voltage gain power converter designed to address the challenges posed by the inherently low output voltage and high output current of fuel cell systems. The proposed converter features a two-stage integrated design, comprising a two-phase interleaved boost converter and a high-gain switched capacitor coupled inductor boost converter. The interleaved design divides the current equally between two phase legs, minimising conduction losses and enhancing efficiency. Additionally, this technique significantly reduces input current ripple, leading to lower fuel cell degradation and improved performance. The switched capacitors and coupled inductor in the high gain boost converter enhance the voltage gain while minimising voltage stress on the active switches and diodes. This approach enables the utilisation of low voltage rated switches and diodes, reducing costs and minimising conduction and switching losses. Additionally, the converter features a common input and output ground to mitigate electromagnetic interference and uses low-side switches to simplify gate circuitry and reduce costs. To validate the proposed design, a 500W prototype is developed and tested in a laboratory environment. The prototype achieves a peak efficiency of 95.52%, a peak-to-peak input current ripple of less than 1.5%, and a voltage gain of 27.8 at a 50% duty cycle.

The emissions that aircraft discharge into the atmosphere are growing daily as a result of advancements in the aviation sector and an increase in air traffic. For this reason, studies on the use of more electricity in the field of aviation have also increased. Development in battery technologies accelerates the transition to electric systems. Hybrid systems are preferred to increase the system efficiency and to ensure longer lifespan of energy sources. With this motivation, a hybrid Unmanned Aerial Vehicle (UAV) system in which Fuel Cell (FC) is the main power source and Lithium Ion (Li-ion) battery assists FC in sudden power changes is modelled and analyzed in Matlab/Simulink environment. In hybrid systems, Energy Management System (EMS) is needed to control energy resources and increase the efficiency of the UAVs. In this study, three different EMS structures in UAVs, including rule-based Thermostat on/off, classical and Type-II fuzzy logic are analyzed in detail. These EMS methods are modeled and examined for the hybrid UAV system. The unique value of this study is to apply three different EMS methods to a UAV powered by a fuel cell and Li-ion battery. An important contribution has been made to researchers that the preferred EMS method may be different depending on the system to be used and the number of resources. Although Type-II fuzzy logic EMS gives better results, it is more complex and the decision-making time is longer. For this reason, traditional fuzzy logic EMS is more widely used in most applications.

This study investigates the commandability in a DC-DC converter for fuel cell applications. In this modular system, each module is established on a three-level converter. The operation areas of the studied converter in terms of commandability have already been investigated. In this paper, a manner to increase the commandable area is suggested. An anti-windup scheme is used to enhance stability under duty-cycle saturation. An indirect sliding-mode controller is utilized to balance DC voltages and control currents with dynamical properties regardless of the operating settings. Simulations and experiments consistent to the theoretical study are conducted to confirm the suggested scheme.