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In this study, multi-walled carbon nanotubes (MWCNTs) were synthesized using the arc discharge method, and gold (Au) , and Au@MWCNT nanoparticles (NPs) were obtained via a rapid and cost-effective chemical reduction method. The performance of these catalysts in ethylene glycol (EG) fuel cells was investigated. According to the Transmission Electron Microscope (TEM) results, the Au particle size was determined to be 3.89 nm, and the MWCNT diameter was found to be 8.21 nm. For EG oxidation, current densities of 33.28 mA/cm2 for Au NPs and 171.28 mA/cm2 for Au@MWCNT NPs were obtained. This result demonstrates that the MWCNT support increased the electrocatalytic activity by a factor of 5.14. Long-term stability tests showed that the MWCNT support exhibited more stable and consistent characteristics and improved CO tolerance. Electrochemical Impedance Spectroscopy (EIS) testing revealed that the MWCNT-supported structure significantly enhanced charge transfer. These findings contribute significantly to the literature by demonstrating the potential for cost-effective production of carbon supported Au NPs, and their application in fuel cells. • MWCNT production using arc-discharge method. • Preparation of Au and Au@MWCNT catalysts and their use in ethylene glycol oxidation studies. • Au@MWCNT exhibits superior electrocatalytic activity towards ethylene glycol oxidation. • Synthesis of more stable catalyst for ethylene glycol oxidation. • Anode catalyst showing high potential for fuel cell applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porous PEDOT as the support of PdSn nanoalloy electrocatalyst. • Pd 4 Sn 6 /PEDOT is created and used for the oxidation of ethylene glycol and ethanol. • The interface electronic structure of Pd was modified by introducing Sn and PEDOT. • It shows outstanding electrocatalytic performance and poisoning-tolerance ability. Developing a novel catalyst with lower noble-metal loading and higher catalytic efficiency is significant for promoting the widespread application of direct alcohol fuel cells (DAFCs). In this work, poly(3,4-ethylenedioxythiophene) (PEDOT) supported the PdSn alloy (PdSn/PEDOT) were simply synthesized and their electrocatalytic performance toward the oxidation of ethylene glycol and ethanol (EGOR and EOR) were investigated in alkaline media, respectively. In comparison with other control catalysts, the optimized Pd 4 Sn 6 /PEDOT catalyst exhibits the highest mass activity (7125/4166 mA mg Pd −1) and specific activity (26/15 mA cm−2) towards EGOR/EOR. The mass activity of Pd 4 Sn 6 /PEDOT for EGOR and EOR are 11.9 and 10.9 times higher than commercial Pd/C, respectively. Moreover, chronoamperometry (CA) and successive cyclic voltammetry (CV) tests show that the CO resistance ability and durability of the Pd 4 Sn 6 /PEDOT catalyst were superior to Pd 4 Sn 6 , Pd/PEDOT and commercial Pd/C catalysts, which can be attributed to the d-band center of Pd can be effectively downshifted and the interface strain effect between electrons caused by the conjugated structure between PEDOT groups. This work provides an effective strategy for the development of highly efficient anode catalysts of DAFCs. [ABSTRACT FROM AUTHOR]

This manuscript basically overviews development, properties, and advancements in the field of three-dimensional graphene nanofoams or aerogels nanostructures. Graphene nanofoam nanostructures have been fabricated using range of techniques like chemical vapor deposition, freeze-drying, and others. Graphene nanofoam has been used to develop the nanocomposite nanostructures with the conjugated and nonconjugated thermoplastic matrices. Consequently, the microstructure and physical features of the graphene nanofoam nanocomposites have been investigated. Ensuing nanocomposites with graphene nanofoam have high surface area, flexibility, electrical and thermal conductivity, mechanical/thermal stability, and other physical characteristics. The performance of three-dimensional graphene nanofoam nanocomposites relies on the interactions between the graphene nanoarchitecture and matrices, formation of interlinked assemblies, and their structure–property relationship. High-performance graphene nanofoam nanocomposites have been applied in the technological fields such as photovoltaics, microbial fuel cells, supercapacitors, radiation shielding, etc. [ABSTRACT FROM AUTHOR]

ABSTRACT Addressing issues of low input voltage in new energy generation systems such as fuel cells, a high step‐up three‐port DC–DC converter for fuel cell/battery hybrid power supply system is proposed. The proposed converter is evolved from Boost three‐port converter, and switch capacitor structure and diode capacitor voltage doubling unit are employed to achieve high voltage gain and low voltage stress. The three ports are connected to fuel cell, battery and load respectively, among which the flow of energy is realized. The steady state performance of this converter in various operating states and design of parameter are presented. Primary competitive advantages compared to similar converters include high voltage gain, continuous input current and its feature of common ground. Moreover, control strategy and compensators under three operating modes are designed to achieve stable output voltage and battery protection. Finally, a 100 W experimental prototype with 15 V input voltage and 24 V battery voltage is established to verify the stable and dynamic performance of the proposed converter. [ABSTRACT FROM AUTHOR]

Hydrogen crossover in water electrolyzer systems equipped with ion exchange membranes (IEM) poses significant safety risks and reduces overall process efficiency. This communication identifies and addresses two critical errors in current hydrogen crossover literature: inaccurate measurement methods and the inappropriate use of permeability (e.g., barrer) to quantify hydrogen crossover. Accurate evaluation of hydrogen crossover through an IEM can be challenging because it is a two-phase material fully hydrated in liquid water. We propose a standardized protocol for accurately measuring hydrogen crossover in fully hydrated IEMs and emphasize the necessity of using flux (e.g., mole∙m−2∙s−1) instead of permeability (e.g., barrer) dimension. The obtained data reveal that normalizing hydrogen crossover by transmembrane pressure and membrane thickness can result in significant errors, with relative errors reaching up to 25%. When applied to the actual electrolysis operation, using the permeability data to predict hydrogen crossover at a current density of 0.4 A cm−2 results in 47% error, with the actual system reaching the lower explosion limit (LEL) while the predicted value does not. Additionally, hydrogen crossover data provides insights into the internal ion channel morphology of IEMs. This communication article intends to convey the current existing safety hazards to the hydrogen research community with a detailed transport models and validation. [Display omitted] • Two fatal errors when describing the hydrogen crossover phenomenon were assessed. • Hydrated ion exchange membrane behaves as a two-phase material. • Inappropriate use of the permeability dimension (barrer) has been evaluated. • Unstandardized measurement methods increase the process safety risk. • Appropriate solutions have been suggested for each hazardous practice. [ABSTRACT FROM AUTHOR]

Electrocatalysts, which are important in increasing the efficiency of fuel cells, still have disadvantages such as low stability and high cost. To overcome these disadvantages, research on the synthesis of low-cost nanoparticle (NP) catalysts has been carried out. In this study, a new approach to develop a low-cost, high electrocatalytic activity and more stable catalyst was realized. In this context; kaolin ((Al 2 O 3 (SiO 2) 2 (H 2 O) 2)) and zinc oxide (ZnO) supported palladium-copper (PdCl 2 –CuCl 2) nanostructures were synthesized by chemical reduction technique. The particle sizes of the synthesized PdCu@kaolin and PdCu@ZnO NPs were found to be 12.02 nm and 23.02 nm, respectively, according to the Debye Scherrer formula. The PdCu@kaolin and PdCu@ZnO NPs obtained within the scope of the study were also used in the anodic oxidation of methanol (CH₃OH), a one-carbon organic compound. According to the results obtained, the current density for methanol oxidation peaks of PdCu@kaolin and PdCu@ZnO NPs were found to be 27.77 mA cm−2 and 41.52 mA cm−2, respectively. It was observed that the ZnO-supported nanoparticles provided 1.49 times higher electrocatalytic activity compared to the other one. The 500-cycle results showed that the ZnO-supported catalyst exhibited a continuously increasing current density. The tests also proved that the catalysts are diffusion-controlled systems and have high stability. Within the scope of the study, ZnO and Kaolin support not only decreased the cost of the catalyst but also significantly affected the electrocatalytic activity, offering better results than the commercial Pd/C catalyst. Cost-effective ceramic structures such as kaolin and ZnO were crucial to show high stability and electroactive behavior close to the literature. The current study has performed an important contribution to the literature on the use of ceramic materials in electrochemistry. • Synthesis of PdCu@kaolin and PdCu@ZnO NPs by chemical reduction. • High electrocatalytic activity of PdCu@kaolin and PdCu@ZnO NPs against methanol oxidation. • Cost-effective and highly stable catalysts. • Efficient anode catalysts for methanol fuel cells. [ABSTRACT FROM AUTHOR]

The energy sector is currently exploring eco-friendly energy conversion and storage devices, as an alternative to traditional fossil fuel devices. A unique hybrid proton exchange membrane is developed for proton exchange membrane fuel cells (PEMFC) and vanadium redox flow battery (VRFB) application. Polymeric nanocomposite membranes are effective for the selective and controlled transportation of ions between the electrodes. This study utilizes various modifiers such as GO, SGO, SPES, and SiC, to modify the PES polymer matrix. Analysis of the functional groups confirmed the presence of modifiers and hydroxyl groups on the nanocomposite membrane. Additionally, the use of Field Emission Scanning Electron Microscopy (FESEM) validated the existence of honeycomb and sponge-like voids as well as the surface morphology on the membrane surface. The incorporation of modifiers into the nanocomposite membrane matrix serves as a reliable barrier for the transport of vanadium ions, leading to a significant reduction in vanadium ion permeability across the membrane. The mechanical properties and ion exchange capacity of nanocomposite membranes are enhanced, while the permeability of VO2+ decreases compared to that of the bare PES membrane. The enhancement of proton conductivity is further achieved with the utilization of modifiers in PES polymer. As compared to bare PES membrane, PES/SPES + SGO (5%) exhibits less than half the permeability for vanadium, and PES/SiC shows 44.03 % elongation means twice of bare PES membrane. [Display omitted] • Influences of GO, SGO, SPES, and SiC, and functional groups in PEMFCs and VRFB is also studied. • PES/SiC shows 44.03 % elongation means twice of bare PES membrane. • Enhanced the proton conductivity through the utilization of modifiers with PES polymer. • PES/SPES + SGO (5%) exhibits less than half the permeability for vanadium. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive optimization approach for a fuzzy logic-based energy management system (EMS) designed for a fuel cell hybrid electric vehicle (FCHEV) powered by a fuel cell and a battery. The aim is to enhance EMS performance and overall system efficiency by optimizing fuzzy logic parameters using a genetic algorithm (GA). The effectiveness of the proposed strategy is demonstrated through simulations using ADVISOR software and the MATLAB/SIMULINK environment. The optimization process consists of four phases: tuning the membership function types, fuzzy variable ranges, membership function parameters, and rule weights. The proposed method has resulted in a significant improvement in the fitness function, highlighting the high sensitivity of the fuzzy logic system to optimization parameters. The optimized EMS is compared with the original one and a thermostat-based strategy built into ADVISOR. Results show a 28.5% improvement in fuel utilization and a 13% reduction in the low-efficiency operation of the fuel cell system. [Display omitted] • A comprehensive optimization approach for energy management system in FCHEVs. • Simulation environment development with real-time FCHEVs interactive monitoring. • FCHEVs Performances improvement in terms of energy efficiency and management. • FCHEVs Energy losses minimization with robust and efficient decision-making. • Innovative solutions provided to overcome the operating constraints of FCHEVs. [ABSTRACT FROM AUTHOR]

Perfluorosulfonic acid (PFSA) polymers are used as electrolyte membranes in polymer electrolyte fuel cells. To investigate the effect on proton conductivity through structural orientation control, we added 1,2,4-triazole to PFSA films during casting to impart anisotropy to the ion-cluster structure of the films. The proton conductivities of the films were found to be high in the film-surface direction and low in the film-thickness direction. Structural analysis using small-angle X-ray scattering suggested that the anisotropy in proton conductivity was due to anisotropy in the ion-cluster structure, which in turn was attributed to the formation of a phase-separated structure via strong bonding between sulfonic acid groups and 1,2,4-triazole during cast film formation and the surface segregation of fluorine. We expect the findings of this study to aid in the fabrication of PFSA films with controlled ion clusters. [ABSTRACT FROM AUTHOR]

Hydrogen zirconium phosphate (HZP) is a ceramic material with the formula HZr 2 (PO 4) 3 that can potentially offer anhydrous protonic conductivity, with thermostability for the intrinsic protons up to 650 °C, and good chemical stability in aqueous environments or acid gases. Despite the attraction of these features for electrolyte applications, such as gas separation, fuel cells or electrolysers, work on this material remains in its infancy. A possible reason for this lack of attention may be related to the complexity to obtain the HZP material as a pure phase. For this reason, the current article examines a new hydrothermal synthesis method to produce the ammonium precursor, NH 4 Zr 2 (PO 4) 3 , in its phase pure form, and consequently a refined overall route to produce the desired HZP target material. In the synthesis of the ammonium precursor, we underscore the precise control of reaction conditions that are necessary to obtain the pure NH 4 Zr 2 (PO 4) 3 material, both in its cubic and hexagonal structural polymorphs. For reaction times of 10 h, the cubic phase is obtained by employing a hydrothermal temperature of 150 °C and an aqueous ammonia volume of 2.1 mL, while the hexagonal phase is obtained for a hydrothermal temperature of 200 °C and an aqueous ammonia volume between 2.3 and 2.4 mL. Subsequently, we investigate the required conditions to convert hexagonal NH 4 Zr 2 (PO 4) 3 fully to hexagonal HZr 2 (PO 4) 3 via thermal treatment at 600 °C for 5 h, assessed by a combination of X-ray diffraction and infrared spectroscopy. In this way this article aims to open up further research on this interesting HZP material by documenting a robust route for its preparation. [ABSTRACT FROM AUTHOR]

Influence of structure and microstructure on the dielectric properties of single-phase solid solution of ZrO2–CeO2 system with 80% CeO2 has been investigated. Highly dense polycrystalline Ce0.8Zr0.2O2 ceramic was synthesized through solid-state reaction route, and its cubic structure was verified through X-ray diffraction and Raman spectroscopy techniques. The compact grain morphology was validated through FESEM with grain size of ~9 μm. Dielectric properties of the Ce0.8Zr0.2O2 were probed by applying ac electric field of different frequencies at variable temperatures. The measured dielectric constant of Ce0.8Zr0.2O2 in the presence of applied ac field of 2 kHz frequency at 300 K is ~1819, is reduced to 27 with an increase in the frequency up to 2 MHz, which is a comparatively high dielectric constant than binary oxides. The high packing fraction of cubic structure of ZrO2–CeO2 with 80% CeO2 showed a small dielectric loss ( tan δ ). The interfacial polarization effect was confirmed by low-frequency dielectric dispersion in ε ′ ′ and ε r . The large conductivity coupled with a relaxation phenomenon at higher temperatures is attributed to the shift from extended hopping to localized ionic transport. Ce0.8Zr0.2O2 showed a negative coefficient of resistance validated through increasing ac conductivity with temperature. A high dielectric constant with small dielectric tangent loss achieved in cubic structured sample established its application in high-performance metal oxide semiconductor field effect transistor (MOSFET) devices along with the formation of advanced solid-electrolytes for solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

The innovation of high‐performance, stable electrocatalysts for clean energy systems faces significant challenges. Metal‐organic frameworks (MOFs), with their porous nature, flexible structures, and homogeneous active site dispersion, have gained interest as unique precursors for carbon‐based catalysts. MOFs' properties significantly enhance catalytic performance in fuel cells. This review highlights recent advancements in MOF design for oxygen electrocatalysis in fuel cells, while also discussing perspectives for future material innovations to improve catalytic activity in this emerging field. [ABSTRACT FROM AUTHOR]

Extensive research on zero-emissions autonomous surface vehicles has been recently carried out, aiming at increasing autonomy. Due to their small size, unmanned vehicles present unique difficulties in terms of weight and dimensions when powering the vehicle with renewable energy sources. In this paper, photovoltaic source, fuel cell and Li-ion battery multi-source configurations are proposed, demonstrating by physical layout and simulation results the feasibility of the prototype, compliant with strict constraints of the vehicle under test. The energy system model of the vehicle under test is implemented in MATLAB/Simulink. A comparison of multi-source energy system configurations is proposed and validated by simulation results in terms of endurance, weight and size. If compared with the original battery-powered vehicle, as shown by comparing simulation results, the endurance is doubled, extended up to 12 h on the most favorable day of the year. The solution even complies with payload and physical dimensions constraints. • Autonomous surface vehicles: overview of the most competitive prototypes. • The SWAMP case study: experimental characterization of the battery-powered version. • Modelling and simulation of SWAMP PV-fuel cell–battery multi-source power supply. • Feasibility analysis and comparison of Multi-source power configurations. • Assessment of endurance, weight and size of multi-source configurations. [ABSTRACT FROM AUTHOR]

Renewable energy sources are now being focused on for usage in electric vehicles. Although majority of electric vehicles run solely on batteries, they have eliminated local emissions but not pollution. To tackle this issue, this research looks into the performance and power management aspects of an electric vehicle's hybrid power system, with a particular emphasis on the interactions between fuel cells, batteries, and photovoltaic (PV) cells. Stable operation is ensured via a bi-directional buck-boost converter, which maintains the voltage from all sources around reference 430 V. Initially, the fuel cell supplies electricity under low light conditions. The PV system and battery take over when the irradiance surpasses 100 W/m2, with the battery first draining and then charging in tandem with the increase in irradiance. 1750 RPM is the constant motor speed that is reached after making the required torque adjustments. A model full electric vehicle with multiple sources has been proposed with an efficient power management algorithm. When the battery is in stationary mode and the state of charge (SOC) is less than 100%, extra solar power is used to charge the battery. The model also takes into consideration using the car for entertainment or gadget charging when the ignition is off. The biogas output can be regulated using an inferential control technique using artificial neural network (ANN) based on the fuel demand or consumption. The system also includes anaerobic digestion of organic waste to provide hydrogen for the fuel cell sustainably from biogas. Power, current, SOC profiles, motor performance graphs, and other validations show that the extensive simulations exhibit efficient power management and a strong model for hybrid electric car power systems. The model has been simulated in the MATLAB Simulink environment and has been tested under realistic conditions. • Proposed new powertrain strategy including PV-battery-PEMFC. • Analysed the heuristic power management for the proposed powertrain strategy. • Utilized biogas to produce Hydrogen for the Vehicle. • Utilized ANN for inferential control of hydrogen generation from biogas plant. [ABSTRACT FROM AUTHOR]

The present article introduces and investigates a new approach for shaving the peak electricity demand and mitigating energy instability. At the heart of this concept is a smart integration for efficient hydrogen production/storage/usage to minimize energy costs and maximize the renewable penetration in the local electricity grid. The system is driven by a wind farm integrated with proton exchange membrane (PEM) electrolyzers and reverse osmosis desalination units for efficient electricity, hydrogen, and freshwater production. It also combines with PEM fuel cells equipped with a hydrogen tank to meet the demand constantly when renewable electricity is unavailable or unstable. The system's practicality is assessed and compared for various Swedish cities with high wind potential from thermodynamic, economic, and environmental aspects to see where it works effectively. The comparative results of various scenarios show that integrating 32 wind turbines, 2 electrolyzers, and 2 reverse osmosis units, with 25% of electricity going to electrolyzers, 20% to reverse osmosis, and 55% to the grid, is the most optimal configuration/allocation. Optimal locations for the power plant are identified in Visby, Halmstad, and Lund due to favorable wind conditions. Setting up the system in Visby could prevent 1878.2 tonnes of CO 2 emissions, generate 93,910 MWh of electricity annually, and create 213 ha of green space. The proposed system in Visby could boast the biggest electricity generation capacity, reaching 11,263 MWh, sufficient to power 938 households. Scaling this model to 12 cities in Sweden could provide the electricity needs of 4500 households, demonstrating the potential for widespread impact. • A novel strategy for peak electricity shaving and wind stability is introduced. • Wind turbines are intelligently integrated with fuel cells to reduce costs. • The system's practicality is compared for various Swedish cities from all facets. • The system in Visby produces 94 GWh of electricity, avoiding 1878 tons of CO 2. • This strategy offers sustainable energy to 4500 homes if scaled up to 12 cities. [ABSTRACT FROM AUTHOR]

Metal hydride based thermally driven systems have attracted significant attention for storing and transporting hydrogen due to their higher energy density. However, their utility can extend to other diverse applications, such as space heating and fuel cell integration, due to their inherent MH formation or decomposition processes. In this perspective, the objective of the present study is to analyse the hydrogen storage or release behavior and thermal characteristics of a newly developed La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 using an annular finned MH reactor under various operating conditions. The absorption outcomes revealed that La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 stored a maximum hydrogen storage capacity of 1.35 wt.% in 1237 s while releasing heat with an average heat output rate of 104.4 W/kg MH at a supply inlet pressure of 25 bar. Also, the achieved peak temperature gain of 14.6 K under similar conditions indicates its utilization in space heating applications, especially in cold countries. The outcomes of desorption at constant pressure indicate that La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 demonstrated 96 % reversibility by releasing 1.31 wt.% of hydrogen in 4509 s with an average heat input rate of 36.4 W/kg MH when operating at a HTF temperature of 303 K. Further, the MH reactor was capable of supplying hydrogen at a discharge rate of 13 lpm for 123.5 min at 323 K HTF temperature, ensuring its possible integration with a 1-kW PEM fuel cell. Further, the La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 achieved gravimetric and volumetric storage densities of 0.76 % and 24.6 kg/m3 of H 2. Moreover, La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 showed excellent reversibility and exhibited superior desorption characteristics compared to La 0.7 Ce 0.1 Ca 0.3 Ni 5. • Hydrogen storage and thermal characteristics of La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 were analysed. • The La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 stored 1.36 wt% in 1237 s at 25 bar feed pressure. • The La 0.7 Ce 0.3 Fe 0.75 Ni 4.25 released 1.34 wt% in 2324 s at HTF temperature of 323 K. • At 13 lpm discharge rate and 303 K, the reactor released 94 % of hydrogen. • The reactor achieved a heat discharge effectiveness of 0.88 at 25 bar supply pressure. [ABSTRACT FROM AUTHOR]

The integration of fuel cell device and supercapacitor device into a singular hybrid power source at the electrode level can make the best use of the advantages of each individual device and more importantly, eliminate the energy loss by virtue of the conversion of chemical energy to electric energy on electrocatalyst material and the storage of electric energy on energy storage material simultaneously. To avoid the use of noble metal electrocatalyst and exploit the dual electrocatalytic and capacitive function of polyaniline, a noble-metal-free fuel cell-supercapacitor hybrid power source employing polyaniline electrode as both anode and cathode is rationally constructed. Based on electrochemical in-situ Raman spectroscopy, this work proposes that the open circuit potential (OCP) of polyaniline electrode is a simple and quick indicator of the redox state of polyaniline. After carefully selecting the fuel and carbon-based support, it is found that the ascorbic acid fuel and the carbon fiber cloth supported polyaniline contributes to the lowest OCP threshold in the anode, and thus the fastest self-charge and largest stabilized open circuit voltage of hybrid power source. The hybrid power source can be self-charged to 0.32 V and yield a peak power density of 0.21 mW cm−2. [Display omitted] • Noble-metal-free fuel cell-supercapacitor hybrid power source on electrode level. • Dual electrocatalytic and capacitive function of polyaniline. • Open circuit potential of electrode can represent the redox state of polyaniline. • Widening redox state threshold enhances the performance of hybrid power source. • Self-charge and discharge performance of hybrid power source. [ABSTRACT FROM AUTHOR]

The graphite-resin composite bipolar plates prepared by the traditional hybrid pressing process exhibit poor conductivity, processability, and wettability due to the graphite flake layer being covered by resin, hindering the formation of a continuous conductive network, which significantly constrains their promotion and application in the field of proton exchange membrane fuel cells (PEMFC). In this paper, an ultra-thin flexible graphite/epoxy composite bipolar plates (BPs) with a thickness of only 0.775 mm is prepared followed by a process of flexible graphite preforming and impregnation curing. The hydrophilicity-modified BPs surface has a contact angle of 59.01° as well as flexural and compressive strengths of 11 MPa and 4 MPa and possesses a high in-plane conductivity of 380 S/cm and a low in-plane specific resistance of 6 mΩ cm2. The electrostack test results show that the hydrophilic runner channel is more conducive to the diffusion and spreading of H 2 O generated from the cathode-side reduction reaction in the flow channel, so that O 2 smoothly passes through the gas diffusion layer to participate in the reduction reaction of O 2 , and exhibits higher electric power at high current density, while the hydrophobically modified BPs has relatively poor overall performance due to ohmic losses. [Display omitted] • A hydrophilic flexible graphite bipolar plate with a contact angle of 59.01° is prepared. • The bipolar plates with excellent flexural strength of 11 MPa and a high in-plane conductivity of 380 S/cm. • The Electricstack has the best overall monolithic voltage and total power when the current density over 1800 mA/cm2. [ABSTRACT FROM AUTHOR]

This paper aims to apply data-driven maximum power point tracking (MPPT) techniques specifically tailored for fuel cell vehicle (FCV) supported hybrid DC microgrids to enhance the power harvesting capability of fuel cell (FC) stacks. Compared to existing MPPT techniques, the current study focuses on developing and evaluating data-driven approaches for maximum power extraction by dynamically determining the operating point of FC power sources through a Zeta converter. An in-depth analysis is conducted by considering parameters such as efficiency, tracking accuracy, response time, and robustness to variations in load demand and operating conditions. The performance results validate that the developed three-layer neural network (TNN)-based MPPT gives better performance findings than Gaussian process regression (GPR), support vector regression (SVR), decision tree regression (DTR), and bagging ensemble decision tree (BEDT). In the performance evaluation phase, a vehicular FC with a rating of 1.26 kW is designed and operated within the temperature range of 320 K to 343 K for hydrogen pressure values ranging from 1 bar to 1.8 bar. For these operational conditions, the prediction accuracy value of the proposed TNN method is 99.6% while the performance values GPR, SVR, DTR, and BEDT are 99%, 98.6%, 97.2%, and 96%. In addition, system efficiency is increased by 0.98%, 1.25%, 2.51%, and 3.02% compared to GPR, SVR, DTR, and BEDT, respectively. [Display omitted] • Developing data-driven algorithms-based MPPT techniques for vehicular FCs. • Providing advantages regarding high-speed tracking capability and tracking accuracy. • Providing stable DC bus voltage operation. • Improving system performance under dynamic load changes and operating conditions. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) are an efficient, reliable and clean source of energy. Predictive modeling and analysis of their performance is becoming increasingly important, especially with the growing emphasis on sustainable development's requirements. However, mathematical modeling is difficult due to the complexity of its internal structure. In this study, the system's electricity generating performance and operational characteristics were analyzed using recent on-site monitoring data first. Then, based on Pearson's correlation coefficient, some of the variables were selected to build two prediction models: an artificial neural network (ANN) model and a multiple linear regression (MLR) model. The models were evaluated on the basis of the normalized mean square error (NRMSE), which was 1.89% for the MLR model and 0.66% for the ANN model, with no overall bias. They were also compared with other existing models, and it was found that the two models used in this study have the advantage of high accuracy and low difficulty. Therefore, the models developed in this study can more accurately and effectively assess the SOFC system's state and can better support work to improve the thermoelectric performance of SOFC systems. [ABSTRACT FROM AUTHOR]

Triblock copolymers such as styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) have been widely used as an anion exchange membrane for fuel cells due to their phase separation properties. However, modifying the polymer architecture for optimized membrane properties is still challenging. This research develops a strategy to control the membrane morphology based on quaternized SEBS (SEBS-Q) by dual-tapering the interfacial block sequences. The structural and transport properties of SEBS-Q with various tapering styles at different hydration levels are systematically investigated by coarse-grained molecular simulations. The results show that the introduction of the tapered regions induces the formation of a bicontinuous water domain and promotes the diffusivity of the mobile components. The interplay between the solvation of the quaternary groups and the tapered fraction determines the conformation of polymer chains among the hydrophobic–hydrophilic subdomains. The strategy presented here provides a new path to fabricating fuel cell membranes with controlled microstructures. [ABSTRACT FROM AUTHOR]

It is well known that numerous operational, material and design variables act upon the performance of a plant-based microbial fuel cell which is an emerging sustainable and versatile energy device like hydrogen fuel cells. However, due to the high complexity of these bioelectrochemical systems, new solutions are required to optimize performance and uncover hidden relationships between dominant fuel cell variables. For this purpose, a database of 229 observations was created for plant-based microbial fuel cells (PMFCs) with 159 descriptor variables and a target variable (maximum power density) based on experimental results from 51 recent publications. Then, some machine learning solutions like principal component analysis (PCA), classification trees and SHapley Additive exPlanations (SHAP) analysis were applied. The PCA indicated mainly two routes involving low and high chemical oxygen demand (COD) towards high maximum power density which consists of the plant family, wastewater type, support media, construction design, separator type, anode and cathode electrodes and light source. SHAP analysis revealed that the most important factors for high performance are operating temperature, natural light, soil support medium, and constructed wetland design. Finally, the classification tree successfully demonstrated nine routes towards high maximum power density which exclude the use of graphite plate cathode electrodes. [Display omitted] • Machine learning was applied to determine high power density routes in PMFC. • Principal component analysis indicated two routes to high maximum power density. • Shapley analysis revealed the most important factors for high-performance. • Most influential variables were found as temperature, natural light, soil support. [ABSTRACT FROM AUTHOR]

Pd-based anode catalysts with superior activity are urgent for formic acid oxidation to further boost the direct formic acid fuel cells (DFAFCs) technologies. Herein, a strategy of ethylenediamine (EDA) modified Pd/C catalyst was developed by two main steps of EDA adsorbed on Vulcan XC-72 carbon by impregnation and Pd nanoparticles loaded on the freeze-dried C-EDA supports by liquid reduction method. The effects of sweep rates and concentrations of EDA on the formic acid electrooxidation were systematically studied. Results showed that the above parameter was optimized as the concentration of EDA of 0.1 mol L−1. Pd nanoparticles with even distribution were fabricated and particle sizes were in the range of 3.5–4.2 nm. In addition, Pd particle size became smaller with the addition of EDA, suggesting that EDA could induce the generation of smaller Pd. Electrochemical measurements demonstrated that the electrocatalytic activity of Pd/C-0.22EDA (1021 mA mg−1) with optimized modification concentration was improved as a factor of 3.82 than that of Pd/C (267 mA mg−1). An enhanced stability (about 41 times higher than Pd/C) and faster charge-transfer kinetics of formic acid electrooxidation were observed for Pd/C-0.22EDA catalyst. CV and CA measurements showed that the most active catalyst was made of the smallest (3.5 nm) Pd nanoparticles for Pd/C-0.22EDA catalyst. The better electrocatalytic performances of Pd/C-0.22EDA might be ascribed to evenly dispersed Pd with relatively smaller particle size, electron regulation between Pd and amine group as well as stable Pd structure. • Ethylenediamine modified Pd/C was firstly prepared to enhance properties of formic acid oxidation. • The adding of EDA contributed to form fine and stable Pd with even distribution. • The modification of EDA greatly enhanced electrocatalytic activity and stability. • The mechanism of enhanced electrocatalytic performances for Pd/C-EDA was discussed. [ABSTRACT FROM AUTHOR]

Although phosphoric acid-doped PBI holds great promise for application in high-temperature proton exchange membrane fuel cells, the stabilities of phosphoric acid-doped membranes are compromised due to the low absorption capacity of phosphoric acid, poor solubility and difficulty in processing. In this study, by introducing poly (5-phenyl-1H-1,2,3-triazole) monomers into the polybenzimidazole main chains, a semi-flexible polybenzimidazole (PBI-QP) was prepared. The mechanical properties of PBI-QP membranes were better than that of PBI membrane. The tensile strength of PBI-QP-20 reached to 130.9 MPa. Compared with PBI, the solubility of PBI-QP has improved significantly. PBI-QP can be easily dissolved in the solvents of DMF, DMSO and formic acid separately at room temperature. All the membranes exhibited super thermal stability. At 800 °C there is still 72% quantity of residue and the thermal stability of PBI-QP can meet the thermal stability requirements of HT-PEMFCs. The membranes of PBI-QP demonstrated high phosphoric acid absorption (ADL 10.5) and enhanced antioxidant properties. The proton conductivity is 64.3 mS∙cm−1 at 170 °C and the peak power density attains an impressive level of 573.6 mW cm−2 at 180 °C. The results indicate that the synthesized HT-PEMs exhibit excellent solubility and impressive peak power density, underscoring their substantial promise for utilization in HT-PEMs. [Display omitted] • A novel semi-flexible polybenzimidazole proton exchange membrane material. • The QP was utilized for the modification of PBI membranes to enhance mechanical properties, ADL and proton conductivity. • The maximum power density can reach 573.6 mW cm−2 at 180 °C without humidity. [ABSTRACT FROM AUTHOR]

In this work, we investigate the electrochemical separation of hydrogen from a 10% H 2 /methane natural gas blend using a single cell experimental setup for electrochemical hydrogen pumping (EHP). Results show that the overall efficiency for hydrogen separation is high, ranging from about 87% at 0.2 A/cm2 to 75% at 0.6 A/cm2. In addition, we develop a zero-dimensional model for the hydrogen separation process including the membrane permeation of H 2 as well as CH 4 , N 2 , and CO 2 as the main components in natural gas. We derive analytical expressions for the permeability of these gases as a function of temperature and membrane humidity using available permeability data. Although the presence of dilutive inert gases poses a challenge, the modelled data indicate that it should be possible to produce fuel cell quality hydrogen using a single hydrogen separation stage. Importantly, this indicates technological feasibility of distributing hydrogen for use in fuel cells through existing natural gas infrastructure. Extension of this research to combined hydrogen separation and compression within the same EHP unit is recommended as future work. • An analytical electrochemical hydrogen pump (EHP) model is developed and validated. • Single cell EHP experiments show high overall hydrogen separation efficiency. • Expressions are developed for the permeability of H 2 , N 2 , CH 4 , and CO 2 in Nafion. • The effects of EHP membrane and operating parameters on H 2 purity are examined. • Fuel cell grade hydrogen extraction is shown to be feasible through system tuning. [ABSTRACT FROM AUTHOR]

The paper compares the properties and activity of palladium clusters deposited on aluminum oxides of different phase compositions obtained by different methods. The numbers of palladium atoms available for the adsorption of hydrazine were determined for each catalyst. A correlation was found between the number of such atoms and the rate of hydrogen formation in the decomposition reaction of hydrazine monohydrate. It was concluded that an active palladium catalyst for the decomposition of hydrazine can be obtained using a modified support with a large specific surface area. The specific surface area and its modification determined the surface coverage with the active reagent. Obviously, the study of the role of various properties of supports in the formation of the active phase should be continued. [ABSTRACT FROM AUTHOR]

The present work assesses the manufacturing method for producing ceramic-based solid oxide fuel cells (SOFC) using compaction and sintering methods, which are combined by adding pore former to improve the porosity of the produced anode. The ratio of pore former varies between 5%, 10% and 15%. The base cermet material in this work is NiOYSZ (Nickle Oxide/Yttria Stabilized Zirconia), which is suitable for high-temperature SOFC. The base material is mixed with pore former at the given ratio, followed by ultrasonic cleaning. This work uses polyethylene glycol (PEG, 10%) as binder material. The produced slurry is then dried in electric oven, continued with the compaction process at a pressure of 135MPa and sintered for 4 hours at 1200°C. The addition of pore former leads to significant improvement in the porosity level, with the highest value of 16.67%. It contributes to the excellent performance of the produced anode, particularly for the permeability value. The NiO-YSZ with 15% pore former has the highest permeability value with average of 0.37 m². Moreover, the detailed permeability profile shows the baseline ratio for adding pore former is between 5% and 10%, which experiences significant variation in the porosity level and permeability value. [ABSTRACT FROM AUTHOR]

In this paper, a meticulous modeling approach is proposed not only for a fuel cell stack itself but also for all auxiliary components that collectively form the fuel cell system. This comprehensive modeling approach encompasses a wide range of components, including, but not limited to, the hydrogen recirculation pump and the air compressor. Each component is thoroughly analyzed and modeled based on the detailed specifications provided by suppliers. This involves considering factors such as efficiency, operating parameters, response times, and interactions with other system elements. By integrating these detailed models, a holistic understanding of the entire fuel cell system's performance can be attained. Such an approach enables engineers and designers to simulate various operating scenarios, predict system behavior under different conditions, and optimize the system design for maximum efficiency and reliability. Moreover, it allows for informed decision-making throughout the system's development, deployment, and operational phases, ultimately leading to more robust and effective energy systems. The model validation is performed by comparing experimental data to theoretical results, and the observed difference does not exceed 3%. [ABSTRACT FROM AUTHOR]

The use of polymer electrolyte membrane (PEM) fuel cells as an alternative to internal combustion engines can significantly contribute to the decarbonization of the transport sector, especially for heavy-duty applications. However, degradation is still an issue for this type of component, affecting their durability and performance. In this scenario, a detailed analysis of the anodic and cathodic distributors' flow-field geometry may help to identify some local stressors that trigger the degradation mechanism, such as local hot spots and reactants not having a uniform distribution. A computational fluid dynamic (CFD) methodology is able to provide a volumetric description of a PEM fuel cell so it can be a useful tool to better understand the physical phenomena that govern the component operations. In this work, the open-source simulation library openFuelCell2 is adopted for a detailed analysis of two different PEM fuel cells characterized by standard distributor geometries, namely a parallel channel geometry and a serpentine configuration. The library, based on the OpenFOAM code, has been extended with a novel implementation accounting for the catalytic activity reduction due to the platinum oxide (PtOx) formation occurring under certain particular conditions. The adopted methodology is firstly validated resorting to experimental data acquired for the two different fuel cell configurations. The analysis highlights that the PtOx formation leads to a reduction in the fuel cell performance reaching up to 60–80% when operating at high voltages. Then, the effect of the distributor geometries on the component performance is investigated by resorting to in-plane and through-plane physical quantity distribution, such as reactant concentration, pressure or velocity fields. While the parallel flow channel configuration shows some diffusion losses under the rib, the serpentine channel geometry configuration can achieve some local performance peaks thanks to the convective flow in the gas diffusion layer (GDL) driven by local pressure gradients. Furthermore, the local enhancement in terms of higher current density under the rib is associated with an effective heat removal due to the high thermal capacity of the bipolar plate, avoiding the generation of local hot spots. [ABSTRACT FROM AUTHOR]

The ability to perform both electrochemical and structural/elemental characterization in the same experiment and at the nanoscale allows to directly link electrochemical performance to the material properties and their evolution over time and operating conditions. Such experiments can be important for the further development of solid oxide cells, solid‐state batteries, thermal electrical devices, and other solid‐state electrochemical devices. The experimental requirements for conducting solid‐state electrochemical TEM experiments in general, including sample preparation, electrochemical measurements, failure factors, and possibilities for optimization, are presented and discussed. Particularly, the methodology of performing reliable electrochemical impedance spectroscopy measurements in reactive gases and at elevated temperatures for both single materials and solid oxide cells is described. The presented results include impedance measurements of electronic conductors, an ionic conductor, and a mixed ionic and electronic conductor, all materials typically applied in solid oxide fuel and electrolysis cells. It is shown that how TEM and impedance spectroscopy can be synergically integrated to measure the transport and surface exchange properties of materials with nanoscale dimensions and to visualize their structural and elemental evolution via TEM/STEM imaging and spectroscopy. [ABSTRACT FROM AUTHOR]

Fuel cells as a new type of clean energy, have become the potential alternatives to traditional fossil fuels. Oxygen reduction reaction (ORR) is the cathode procedure of fuel cells. It is of great significance to study more stable and economical high-activity electrocatalysts for the commercial development of fuel cells. Based on the advantages of high entropy effect, this work prepared multiple transition metal co-doped NSC materials (M-NSC, M =Co, Fe, Ni, Mn, Ce), in order to improve the catalytic performance of cathode catalysts. (CeMnFeCoNi)-NSC catalysts with different metal/carbon ratio were synthesized by high-temperature pyrolysis, and the influence of metal addition amounts on the microstructure and catalytic performance were studied. (CeMnFeCoNi)-NSC shows two-dimensional layered structure, providing a larger specific surface area and more active sites. Then (CeMnFeCoNi)NSC was used as the cathode catalyst of direct methanol fuel cells (DMFC) and direct borohydride fuel cells (DBFC), and the peak power densities were 19. 86 and 73.81 m·W cm-2, respectively, Compared with that of Fe-NC based DMFC and DBFC, the peak power densities were 7.92 and 52. 12 m·W cm-2, respectively. The high performance of (CeMnFeCoNi)NSC is mainly attributed to the M-N4 groups formed by metals and nitrogen, and the synergistic effect among multiple metals. Furthermore, it was found that the superior cell performance was achieved with the metal-to-carbon ratio of 1:50. This study provides a new idea for the composition design and performance regulation of carbon-based electrocatalysts. [ABSTRACT FROM AUTHOR]

Despite being a cutting‐edge technology, the proton exchange membrane fuel cell (PEMFC) generates a lot of heat as it works, which makes it wasteful with energy. In order to enhance energy efficiency via waste heat recovery, we provide and analyze a novel integrated energy system that utilizes PEMFC and ORC technology. There are a lot of ways to put the waste heat from fuel cells (FCs) to good use, but the most efficient one is the organic Rankine cycle (ORC) with the right working fluid. This research aims to find the optimal way to use the waste heat of the FC by testing several working fluids. The optimal solution is derived using a genetic algorithm by monitoring the objective functions that characterize the system's overall performance as they vary across different system parameters. The results show that the proposed efficient integration achieves high energy and exergy efficiency levels and achieves rates of total cost and environmental impact that are within acceptable limits. Since the fuel usage element's content significantly affects the system indicators in several ways, the results also demonstrate that it is quite relevant. Since the exergo‐environmental metric and the exergy efficiency meter are always moving in different directions, choosing a design condition that meets several requirements is crucial. According to the results, fuel cells had the highest irreversibility rate at 12.2, making them the most energy‐conserving piece of machinery. [ABSTRACT FROM AUTHOR]

The rapid development of the transportation sector requires consideration of fossil fuel consumption and its negative effects. For this reason, electric vehicles have started to be an alternative to conventional ones that use fossil fuels. As a transportation fuel, hydrogen can be considered as a suitable alternative to fossil fuels. The durations for hydrogen refueling and fossil fuel refueling in conventional vehicles are close to each other. To promote the use of fuel cell vehicles, it is imperative to build the necessary facilities, including hydrogen fuel stations, that will support this need in the near future. In this study, the refueling of the hydrogen tank is simulated for the use of a fuel cell electric vehicle in real usage conditions and it takes 280 s to supply 4.34 kg of hydrogen to the tank of the vehicle, which is driven with a range of 650 km. The fuel economy of the vehicle is compared with conventional vehicles and was found to be 11.0 ¢/km and 10.2 ¢/km, respectively. Renewable supported production technologies are taken as a reference in hydrogen pricing, and these costs are even lower in hydrocarbon-based production. Depending on the source of the hydrogen, the emission intensity of the vehicle can be reduced to 4.7 gCO 2 /km with green hydrogen technologies, while it can be up to 166.8 gCO 2 /km in case of intensive fossil resource use. This study shows that a fuel cell vehicle can compete with traditional ones in terms of range, refueling time and fuel economy and is more environmentally friendly. • An FCEV is simulated in the designed driving cycle based on real-world data. • Vehicle fuel consumption is 6.67 gH 2 /km or its gasoline equivalent is 2.51 L/100 km. • The vehicle can travel 650.3 km with 4.34 kg of hydrogen. • Refueling time for a 650 km trip takes 280 s. • The emission value of the vehicle is between 4.7 and 166.8 gCO 2 /km. [ABSTRACT FROM AUTHOR]

In disaster areas, Cells on Wheels (COW) mobile infrastructures are one of the most widely used solutions to restore communications lost due to power grid collapse or physical damage. The biggest problem with such systems is the low operating time and the inability to ensure energy continuity due to logistical problems. In this proposed study, the solution to the stated problem is focused on, and the use of hydrogen, which is the most important energy option of the future, is proposed as an innovative approach. The PV-hydrogen/fuel cell hybrid energy generation and storage system ensures the continuity of energy required for COW. In this study, the system is analyzed under realistic conditions using radiation and temperature data from different seasons in the disaster area. The energy needed in the proposed system is provided by PV and fuel cell with a control strategy. In addition, the electrolyser in the system contributes to the continuity of the energy by producing hydrogen with the excess energy provided by the PV. COW mobile infrastructures, which have a working time of 3 h under normal conditions, have been provided with energy continuity throughout the day thanks to the proposed system. As a result, this study has revealed that it is a solution to an important problem, especially in disaster areas where information flow is very critical. • The energy system is designed for COW used in disaster areas. • With the sustainability of energy, 24 h of uninterrupted operation is ensured. • The success of the system was tested under different climatic conditions. • The proposed system contributes to achieving zero emission targets. [ABSTRACT FROM AUTHOR]

Due to the widespread use of multi-generation systems utilizing renewable energy sources and the growing global demand for such systems from both economic and environmental considerations, numerous researchers have focused on the design and evaluation of their performance. To this end, this research presents a biomass-based multi-generation system with an innovative and practical design that can generate electricity, heat, and hydrogen. This system includes a modified gas turbine cycle, a supercritical CO 2 (SCO 2) cycle, a transcritical CO 2 (TCO 2) cycle, a proton exchange membrane (PEM) electrolyzer, and a PEM fuel cell unit. This study aims to evaluate the impact of various biomass sources (paper, wood, paddy husk, and municipal solid waste) on the system performance. The proposed system has been analyzed using the first and second laws of thermodynamics. This system uses the maximum capacity to produce power, heat and hydrogen. A fuel cell unit has been used to consume hydrogen and generate more electricity. In the basic mode, the system has energy and exergy efficiencies of 47.89% and 32.26%, respectively, and can produce 2.74 kg/h of hydrogen. The biomass fuel consumption rate within the system is 0.055 kg/s. The overall exergy destruction of the system amounts to 1240 kW, with the biomass boiler and the condenser being the components that experience the greatest exergy destruction, registering values of 535.5 kW and 432.3 kW, respectively. Notably, employing municipal waste as biomass increases the system's exergy efficiency to 33.16%. • To investigate a biomass-driven system for producing power, hydrogen, and heating. • To evaluate the impact of various biomass sources on the system performance. • To use PEME for hydrogen and PEMFC for power and heat production. [ABSTRACT FROM AUTHOR]

The uncertain nature of renewable energy sources (RES) and cyber-attack have become a critical concern in load frequency control (LFC). Attacks on the communication lines of microgrids (MGs) containing critical/sensitive systems are always possible and can disrupt the operation of MGs. To address these challenges, the study focuses on the utilization of hydrogen as a storable energy source to enhance effective LFC in the face of substantial power fluctuations resulting from the uncertainties associated with Renewable Energy Sources. The research investigates a microgrid structure that comprises electrolysis and fuel cell systems, enabling the storage of surplus energy generated by systems utilizing intermittent energy sources, which are expected to become more prevalent in the near future. To illustrate our target, a microgrid structure with RES is modeled by utilizing MATLAB/Simulink with cyber-attack mechanism. In this study, a type 2 fuzzy logic control-based LFC scheme is proposed to reduce frequency deviations caused by potential cyberattacks that may target energy storage systems responsible for ensuring the sustainability of energy in an isolated MG. The primary objective of this study is to achieve optimal LFC in an isolated MG that may be susceptible to both random power fluctuations and potential cyberattacks. The dual-input interval type 2 fuzzy logic controller - fractional order tilt-integral-derivative cascade controller (DIT2FLC-FOTID) has been developed for the LFC of the designed microgrid. The parameters of the FOTID controller are determined through optimization, while the suitable input signal for the FOTID controller is determined using DIT2FLC. The performance of the proposed controller has been examined for various scenarios. In all scenario analyses, the proposed controller consistently demonstrates improvements in the frequency response of the microgrid by over 67% compared to the Fuzzy TID controller, and by over 87% compared to the FOTID controller, across various performance criteria. • An environmentally friendly microgrid structure using hydrogen as a carbon-free fuel was proposed to further improve energy sustainability. • The uncertain nature of renewable energy sources makes it difficult to the load frequency control of microgrids. • Cyber-attacks on communication lines of microgrids are inevitable. • A robust controller is proposed for MGs with cyber-attackable and uncertain nature of RES. [ABSTRACT FROM AUTHOR]

Synchronous generators have a significant role in the power system for active and reactive power control. However, the increasing usage of inverter-based power distribution systems, along with the growing prominence of renewable energy sources, raises concerns about their reliability and stability. The objective of this study is to address the reactive power load demands by employing a Static Synchronous Compensator (STATCOM) in a grid with a fuel cell stack. To reduce the threat posed by the use of inverter-sourced power transmission elements on power systems, a combined fuel cell and STATCOM structure is proposed and it is shown in the MATLAB/Simulink environment that this structure has the dynamic characteristics of a synchronous generator. This study emphasizes that the fuel cell+STATCOM structure can be used as a synchronous generator and presents a different approach in the literature. The system comprises the fuel cell, harmonic filter, STATCOM, load, coupling inductances, measurement units, and PI controller. This system is aimed to create a system that can operate stably in different reactive power requirements and meet the determined reactive power requirement in any case. This study aims to meet the need for large power synchronous generators. • Equivalent synchronous generator for modern power systems is proposed. • The active power required by the load is supplied by the fuel cell. • The reactive power required by the load is met by the STATCOM. • The system was tested for different load cases. • The operation of the proposed system was verified by simulation results. [ABSTRACT FROM AUTHOR]

This study proposes a machine learning-based maximum power point tracking method for fuel cell systems. Initially, a Matlab model was developed to accurately represent the behaviour of a proton exchange membrane fuel cell. A dataset for training of machine learning methods was collected from fuel cells operating under different conditions. To demonstrate the effectiveness of the proposed method, comparison studies were conducted using classical methods, namely "perturb and observe" and "incremental conductance" under varying temperature and pressure conditions. Notably, under the condition of temperature and pressure variation, the output powers obtained from the system were 2005.2 W for support vector machine and 2018.5 W for linear regression at 4.5 s, while the output powers of 'incremental conductance' and 'perturb and observe' were 1989.6 W and 1986.3 W, respectively. The results demonstrate that the proposed method contributes to a more efficient operating condition and faster dynamic responses to changes. • An MPPT method based on machine learning is proposed. • The utilization of a machine learning-based MPPT technique enhances the efficiency of PEMFC. • By utilizing the machine learning, the PEMFC system adapts to varying operating conditions. • The proposed method provides an efficient solution for maximizing power extraction from PEMFC. [ABSTRACT FROM AUTHOR]

Structural changes in electrical energy systems are occurring rapidly. Due to the development of technology and the increase in energy consumption, the importance and impact of nanogrids in the energy system is increasing. It is very difficult to sustain nanogrids as offgrid. Therefore, this study thoroughly examines the most efficient controller designs for nanogrids that use fuel cells as their primary source of energy. In addition, Dwarf Mongoose Optimization (DMO), a new effective optimization technique, is used to determine controller gains in nanogrid systems for the first time in the literature. Controller gains for different objective functions such as ISE, IAE, ITSE and ITAE are determined using classical PID controllers and two degrees of freedom (2 DOF) PID controllers. Moreover, sensitivity analysis is carried out for both variable and constant load scenarios. The constant load is selected as 0.25 pu, and variable load is chosen from values ranging from 0.15 pu to 0.75 pu. In addition, the response of the system to parameter changes is examined by increasing or decreasing the time constants in all load cases. The system parameters are changed from −20 % to +40 % in 0.05 intervals. It has been noted that the suggested controller topologies perform differently depending on the objective functions. Thus, a significant contribution has been made to researchers to indicate the effectiveness of various control structures in fuel cell powered nanogrids. [Display omitted] • Classical and 2 DOF PID controllers are investigated in fuel cell powered nanogrids. • DMO algorithm is proposed to determine the controller gains. • Sensitivity analyses are examined for different load cases. • The performances are analysed for different objective functions. • The controllers demonstrate different performance for different objective functions. [ABSTRACT FROM AUTHOR]

The single‐atom Fe−N−C catalyst has shown great promise for the oxygen reduction reaction (ORR), yet the intrinsic activity is not satisfactory. There is a pressing need to gain a deeper understanding of the charge configuration of the Fe−N−C catalyst and to develop rational modulation strategies. Herein, we have prepared a single‐atom Fe catalyst with the co‐coordination of N and O (denoted as Fe−N/O−C) and adjacent defect, proposing a strategy to optimize the d‐orbital spin‐electron filling of Fe sites by fine‐tuning the first coordination shell. The Fe−N/O−C exhibits significantly better ORR activity compared to its Fe−N−C counterpart and commercial Pt/C, with a much more positive half‐wave potential (0.927 V) and higher kinetic current density. Moreover, using the Fe−N/O−C catalyst, the Zn‐air battery and proton exchange membrane fuel cell achieve peak power densities of up to 490 and 1179 mW cm−2, respectively. Theoretical studies and in situ electrochemical Raman spectroscopy reveal that Fe−N/O−C undergoes charge redistribution and negative shifting of the d‐band center compared to Fe−N−C, thus optimizing the adsorption free energy of ORR intermediates. This work demonstrates the feasibility of introducing an asymmetric first coordination shell for single‐atom catalysts and provides a new optimization direction for their practical application. [ABSTRACT FROM AUTHOR]

The single‐atom Fe−N−C catalyst has shown great promise for the oxygen reduction reaction (ORR), yet the intrinsic activity is not satisfactory. There is a pressing need to gain a deeper understanding of the charge configuration of the Fe−N−C catalyst and to develop rational modulation strategies. Herein, we have prepared a single‐atom Fe catalyst with the co‐coordination of N and O (denoted as Fe−N/O−C) and adjacent defect, proposing a strategy to optimize the d‐orbital spin‐electron filling of Fe sites by fine‐tuning the first coordination shell. The Fe−N/O−C exhibits significantly better ORR activity compared to its Fe−N−C counterpart and commercial Pt/C, with a much more positive half‐wave potential (0.927 V) and higher kinetic current density. Moreover, using the Fe−N/O−C catalyst, the Zn‐air battery and proton exchange membrane fuel cell achieve peak power densities of up to 490 and 1179 mW cm−2, respectively. Theoretical studies and in situ electrochemical Raman spectroscopy reveal that Fe−N/O−C undergoes charge redistribution and negative shifting of the d‐band center compared to Fe−N−C, thus optimizing the adsorption free energy of ORR intermediates. This work demonstrates the feasibility of introducing an asymmetric first coordination shell for single‐atom catalysts and provides a new optimization direction for their practical application. [ABSTRACT FROM AUTHOR]

The growing concern about climate change and the contemporary increase in mobility requirements call for faster, cheaper, safer, and cleaner means of transportation. The retrofitting of fossil-fueled piston engine ultralight aerial vehicles to hydrogen power systems is an option recently proposed in this direction. The goal of this investigation is a comparative analysis of the environmental impact of conventional and hydrogen-based propulsive systems. As a case study, a hybrid electric configuration consisting of a fuel cell with a nominal power of about 30 kW, a 6 kWh LFP battery, and a pressurized hydrogen vessel is proposed to replace a piston prop configuration for an ultralight aerial vehicle. Both power systems are modeled with a backward approach that allows the efficiency of the main components to be evaluated based on the load and altitude at every moment of the flight with a time step of 1 s. A typical 90 min flight mission is considered for the comparative analysis, which is performed in terms of direct and indirect emissions of carbon dioxide, water, and pollutant substances. For the hydrogen-based configuration, two possible strategies are adopted for the use of the battery: charge sustaining and charge depleting. Moreover, the effect of the altitude on the parasitic power of the fuel cell compressor and, consequently, on the net efficiency of the fuel cell system is taken into account. The results showed that even if the use of hydrogen confines the direct environmental impact to the emission of water (in a similar quantity to the fossil fuel case), the indirect emissions associated with the production, transportation, and delivery of hydrogen and electricity compromise the desired achievement of pollutant-free propulsion in terms of equivalent emissions of CO2 and VOCs if hydrogen is obtained from natural gas reforming. However, in the case of green hydrogen from electrolysis with wind energy, the total (direct and indirect) emissions of CO2 can be reduced up to 1/5 of the fossil fuel case. The proposed configuration has the additional advantage of eliminating the problem of lead, which is used as an additive in the AVGAS 100LL. [ABSTRACT FROM AUTHOR]

Solid Oxide Fuel Cells (SOFCs) are capable of generating electrical and thermal power with very high conversion efficiency and almost no pollutant emissions into the atmosphere. Despite extensive literature on SOFC-based energy system models and experimental testing at the cell and short-stack level, there is currently a lack of performance data for SOFC modules under actual field conditions. To fill this gap, the present work investigates the energy and environmental performance of six SOFC modules, ranging in size from 10 to 60 kW, over thousands of hours of operation. These systems, supplied by the three leading SOFC manufacturers in Europe, have been installed and operated in different non-residential buildings worldwide, as part of the European Comsos project. The aim of this study is to establish a comprehensive set of field operation data to characterise commercial-scale SOFC systems. Specifically, raw data are processed to derived electrical and thermal efficiency maps, degradation rates and pollutant emissions, including particulate matter (PM), nitrogen oxides (NO x) and carbon monoxide (CO). A comparison with competing technologies is also provided to better highlight the potential benefits of adopting SOFC-based cogeneration systems. Values in the range of 51–61% were found for the system-level electrical efficiency under rated conditions. The electrical efficiency also remained consistently high across a wide modulation range (between 50% and 100% of rated power), with peak values reaching 65%. In addition, promising results were obtained for the average percentage loss in electrical efficiency, with a minimum value of 0.7%/1000 h. Regarding the environmental analysis, NO x and CO emissions were analysed at both constant and variable power output, proving to be impressively low across the entire modulation range. The same applies to PM concentrations, which were below ambient level. Overall, SOFCs demonstrated to be one of the best cogeneration solutions for commercial-scale systems (tens to hundreds of kW in size), from both an energy and environmental perspective. However, further reductions in costs and dedicated financial schemes are necessary for a widespread market penetration. [Display omitted] • Energy and environmental performance from the field operation of six SOFC systems. • Rated AC electrical efficiency of 51%–61%, with stable performance at partial load. • Maximum AC electrical efficiency of up to 65%. • Percentage loss in AC electrical efficiency of 0.7 %/1000 h. • Very low values for NO x and CO emissions, even at partial load. [ABSTRACT FROM AUTHOR]

Coordination environment engineering is developed to synthesize Fe SA /NSC catalysts with the tailored N, S co-coordinated Fe atomic site. [Display omitted] • The Fe-N 3 S active site with the optimized electronic structure is constructed. • S doping promotes the OH* desorption, thus leading to enhanced kinetics process. • The catalyst displays impressive ORR activity in both alkaline and acidic mediums. • The catalyst exhibits excellent performance in Zn-air batteries and fuel cells. Atomically dispersed iron–nitrogen-carbon (FesbndNsbndC) materials have been considered ideal catalysts for the oxygen reduction. Unfortunately, designing and adjusting the electronic structure of single-atom Fe sites to boost the kinetics and activity still faces grand challenges. In this work, the coordination environment engineering is developed to synthesize the Fe SA /NSC catalyst with the tailored N, S co-coordinated Fe atomic site (Fe-N 3 S site). The structural characterizations and theoretical calculations demonstrate that the incorporation of sulfur can optimize the charge distribution of Fe atoms to weaken the adsorption of OH* and facilitate the desorption of OH*, thus leading to enhanced kinetics process and intrinsic activity. As a result, the S-modified Fe SA /NSC exhibits outstanding catalytic activity with the half-wave potentials (E 1/2) of 0.915 V and 0.797 V, as well as good stability, in alkaline and acidic electrolytes, respectively. Impressively, the excellent performance of Fe SA /NSC is further confirmed in Zn-air batteries (ZABs) and fuel cells, with high peak power densities (146 mW cm−2 and 0.259 W cm−2). [ABSTRACT FROM AUTHOR]

This study introduces a novel combination of sulfur-doped reduced graphene oxide (S-rGO), zinc ferrite (ZnFe 2 O 4) and nickel cobalt layered double hydroxide (NiCoLDH) as an efficient and low-cost electrocatalyst for oxygen reduction reaction (ORR) for the first time. The hydrothermal method is used to synthesize all samples including graphene oxide (GO), S-rGO, NiCoLDH, ZnFe 2 O 4 and S-rGO/ZnFe 2 O 4 /NiCoLDH hybrids. X-ray diffraction (XRD) analysis, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), energy dispersive x-ray analysis (EDX), electrochemical surface area (ECSA), and fourier transform infrared spectroscopy (FTIR) analysis are used to determine the structure of synthesized electrocatalysts, physical properties, and morphology. The electrochemical measurements are carried out using cyclic voltammetry (CV), linear scanning voltammetry (LSV), chronoamperometry (ChA), and electrochemical impedance spectroscopy (EIS). The results for all samples are compared with the Pt/C commercial catalyst. According to the electrochemical results, the S-rGO/ZnFe 2 O 4 /NiCoLDH electrocatalyst has the best electrochemical performance. Moreover, the nanocomposite exhibited better electrocatalysis, a high diffusion limiting current density of −5.4 mA cm−2 and an onset potential of 0.03 V. Based on the results of this study, the LDH enhances electrical conductivity, electrocatalytic activity, active surface area, and stability of the catalyst for ORR after combining with carbon bases and ferrite. [Display omitted] • An electrochemical method was utilized for NiCo-LDH on S-rGO/ZnFe 2 O 4. • S doped reduced graphene oxide was used in a composite for improving its ORR activity. • NiCo-LDH was used as electrocatalyst for ORR. • S-rGO/ZnFe 2 O 4 /NiCo-LDH hybrid showed better ORR activity. [ABSTRACT FROM AUTHOR]

As global environmental issues become increasingly prominent, the maritime industry faces an urgent imperative to curtail carbon emissions and mitigate environmental impact. Green marine alternative fuels are actively addressing these challenges. Global patent data are collected, and four sub-technologies of green fuel technologies in the maritime field are extracted based on Natural Language Processing. To evaluate the innovation trends and evolutionary paths of these technologies, the Main Path Analysis is employed to identify the evolution path of technologies and the evolution situation of major innovative entities, while the Social Network Analysis was used to present the results visually. These four sub-technologies (Hydrogen & Fuel Cell, Methanol & Ethanol, Ammonia, and LNG & LPG) have occupied the mainstream of fuel technology in maritime over the past five years, with 34.6% of patents, 38.3% of patent citations, and 93.9% of technological influence, accounting for 27.4%, 20.5%, 16.7% and 44.3%, respectively. Ammonia, and Hydrogen & Fuel Cell are springing up like mushrooms after rain, while the development of LNG & LPG, Methanol & Ethanol is relatively mature. Each of these technologies showcases distinct developmental paradigms. We elaborated on developmental paradigms and future research priorities of each technology in the conclusion. In addition, new technological opportunities are also created through the cross-fertilization of technologies. In particular, integrated systems for hydrogen production, storage, and combustion on LNG ships, and maritime hybrid power systems driven by ammonia and hydrogen have opened a new window for the green development of maritime fuels. • Four green fuel technologies account for 93.9% of maritime fuel technological influence in the past five years. • Hydrogen & Fuel Cell and Ammonia rapidly expand, while LNG & LPG and Methanol & Ethanol are relatively mature. • This study details the unique development paradigms and future research priorities for each technology. • Hydrogen systems on LNG ships and hybrid ammonia-hydrogen maritime power open new avenues for green fuel development. [ABSTRACT FROM AUTHOR]

Carbon fiber paper (CFP) is one of the most widely used gas diffusion layer materials for proton exchange membrane fuel cells (PEMFC) due to its excellent properties such as high conductivity, high strength, high air permeability and corrosion resistance. In this study, CFP was prepared using the phenolic resin (PF) in-pulp addition method. The effect of PF content on the properties of hot-pressed paper (HPP) and CFP was investigated. The results showed that when the dosage of polyethylene oxide (PEO) was 1.5 wt%, the flocculation effect of PEO on PF was basically complete, and the water filterability and retention of carbon fiber pulp were relatively optimal. After HPP was carbonized into CFP, the hydrophobicity, average pore size, porosity, and air permeability increased, while the resistivity and tensile strength decreased. With the increase of PF content, the tensile strength of CFP gradually increased, while the average pore size, porosity, air permeability and resistivity decreased. When the PF content was 250 wt%, the average pore size of CFP was 36.5 μm, the water contact angle was 127°, the porosity was 69.7%, the air permeability was 7.81 × 103 mL mm/(cm2·h·mmHg), the resistivity was 21.1 mΩ cm, and the tensile strength was 15.7 MPa. In addition, the CFP prepared using PF in-pulp addition method had a relativity uniform pore size distribution and high air permeability. Therefore, this work shows that the CFP prepared using this technique exhibits excellent comprehensive performance, and enables the manufacturing of CFP to be more efficient, low-cost, and environmentally friendly. [Display omitted] • Carbon fiber paper was prepared efficiently using the phenolic resin in-pulp addition method. • Polyethylene oxide exhibits strong adsorption ability on phenolic resin in carbon fiber pulp. • The melting temperature of phenolic resin is a critical point in the preparation process of carbon fiber paper. • Carbon fiber paper possesses a relatively uniform pore size distribution and high air permeability. [ABSTRACT FROM AUTHOR]

Summary The increasing environmental issues such as climate change and air pollution require energy saving and emission reduction in various fields, such as manufacturing, building, and transportation. To address the above problem, proton‐exchange membrane fuel cells (PEMFC) gradually become promising green energy conversion device due to the advantages of zero pollution, high efficiency, and low operating noise. However, the durability problem has extremely limited the PEMFC large‐scale commercial application. To prolong the service life of PEMFC, performance degradation prediction is an effective method. This paper proposes a multi‐step performance degradation prediction method for proton‐exchange membrane fuel cells based on CatBoost feature selection, convolution computing, and interactive learning mechanism. CatBoost is used to evaluate the importance of the monitor parameters on performance degradation. The evaluation results and PEMFC degradation mechanism analyses are used to select the monitor parameters for construing the prediction model. Based on the 1D convolutional layer and the interactive learning mechanism, the prediction model is proposed to extract the deep features from the monitor data to predict the performance degradation of the fuel cell system. In particular, the multi‐step prediction is performed by the configurable sliding window. The effectiveness of the proposed method is verified on real experiment datasets, and the experiment results show that the proposed method is particularly effective for multi‐step degradation prediction and decreases the computation by feature selection and 1D convolution layer. [ABSTRACT FROM AUTHOR]

Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system. • HMS methods for FC diagnosis are introduced and classified into three main categories. • New scheme is introduced categorising HMS methods by approach and characteristics. • Matrix evaluation is introduced rating HMS methods for individual FC application. • Method properties affect classification results requiring evaluation for each use case. • For FCs, feature extraction, reduction and fault classification methods are chosen. [ABSTRACT FROM AUTHOR]

The intermittency of renewable energy technologies requires adequate storage technologies. Hydrogen systems consisting of electrolysers, storage tanks, and fuel cells can be implemented as well as batteries. The requirements of the hydrogen purification unit is missing from literature. We measured the same for a 4.5 kW PEM electrolyser to be 0.8 kW for 10 min. A simulation to hybridize the hydrogen system, including its purification unit, with lithium-ion batteries for energy storage is presented; the batteries also support the electrolyser. We simulated a scenario for operating a Dutch household off-electric-grid using solar and wind electricity to find the capacities and costs of the components of the system. Although the energy use of the purification unit is small, it influences the operation of the system, affecting the sizing of the components. The battery as a fast response efficient secondary storage system increases the ability of the electrolyser to start up. • Operating electrolysers off-grid using renewable energy systems. • Electrolysis systems require additional power to purify hydrogen for safe storage. • Purifying hydrogen requires negligible energy but can interrupt the operation. • Adding batteries as buffers for electrolysers stabilizes the operation off-grid. • Combining wind and solar reduces the capital costs when focusing on stable operation. [ABSTRACT FROM AUTHOR]