Polymer Exchange Membrane Fuel Cell Research Articles

"Straw in the Clay Soil" Strategy: Anticarbon Corrosive Fluorine-Decorated Graphene Nanoribbons@CNT Composite for Long-Term PEMFC.

Carbon corrosion poses a significant challenge in polymer exchange membrane fuel cells (PEMFCs), leading to reduced cell performance due to catalyst layer degradation and catalyst detachment from electrodes. A promising approach to address this issue involves incorporating an anticorrosive carbon material into the oxygen reduction reaction (ORR)electrode, even in small quantities (≈3wt% in electrode). Herein, the successful synthesis of fluorine-doped graphene nanoribbons (F-GNR) incorporated with graphitic carbon nanotubes (F-GNR@CNT), demonstrating robust resistance to carbon corrosion is reported. By controlling the synthesis conditions using an exfoliation method, the properties of the composite are tailored. Electronic structural studies, employing density functional theory (DFT) calculations, to elucidate the roles of fluorine dopants and graphitic carbon nanotubes (CNTs)in mitigating carbon corrosion are conducted. Physicochemical and electrochemical characterization of F-GNR@CNT reveal its effectiveness as a cathode additive at the single-cell scale. The addition of F-GNR@CNT to the Pt/C cathode improves durability by enhancing carbon corrosion resistance and water management, thus mitigating the flooding effect through tailored surface properties. Furthermore, advanced impedance analysis using a transmission line model is performed to gain insights into the internal resistance and capacitive properties of electrode structure.

Red-Billed Blue Magpie Optimizer for Electrical Characterization of Fuel Cells with Prioritizing Estimated Parameters

The red-billed blue magpie optimizer (RBMO) is employed in this research study to address parameter extraction in polymer exchange membrane fuel cells (PEMFCs), along with three recently implemented optimizers. The sum of squared deviations (SSD) between the simulated and measured stack voltages defines the fitness function of the optimization problem under investigation subject to a set of working constraints. Three distinct PEMFCs stacks models—the Ballard Mark, Temasek 1 kW, and Horizon H-12 units—are used to illustrate the applied RBMO’s feasibility in solving this challenge in comparison to other recent algorithms. The highest percentages of biased voltage per reading for the Ballard Mark V, Temasek 1 kW, and Horizon H-12 are, respectively, +0.65%, +0.20%, and −0.14%, which are negligible errors. The primary characteristics of PEMFC stacks under changing reactant pressures and cell temperatures are used to evaluate the precision of the cropped optimized parameters. In the final phase of this endeavor, the sensitivity of the cropped parameters to the PEMFCs model’s performance is investigated using two machine learning techniques, namely, artificial neural network and Gaussian process regression models. The simulation results demonstrate that the RBMO approach extracts the PEMFCs’ appropriate parameters with high precision.

A model reduction framework of flow maldistribution and mitigation strategy for parallel flow field based polymer exchange membrane fuel cell

Mitigating flow maldistribution plays a crucial role in next-generation industry-used parallel-based flow field design for polymer exchange membrane fuel cells (PEMFCs), especially for larger-size cells and higher current density. In this study, a model reduction framework is proposed to alleviate flow maldistribution among parallel gas flow channels and associated computational burden. The gas flow features and electrochemical kinetics of four mitigation strategies including expanded manifold, partially porous media, dot matrix, and partially narrow structures are investigated in detail. The results indicate that the fuel cell model and a fluid flow model without the reactions show similar maldistribution features among parallel channels. The observed flow maldistribution can be effectively reduced by mitigating designs. Expanding the manifold space significantly alleviates the vortex impeding the gas entry to individual channel inlet, and the inlet exhibits better flow uniformity and pressure drop in the direction perpendicular to the channel than in the parallel to. The fully-inserted and manifold-inserted porous media methods present symmetrical quadratic-shaped flow patterns among channels, while that of the partially-inserted porous media inside channels is unsymmetrical. Additionally, the concentration loss with a partially narrowed design decreases by 44.7%, 12.9%, and 24.2% compared with the expanded manifold, partial porous media, and dot matrix designs at 1.8 A cm−2 owing to better flow uniformity and mass transport. These model framework and mitigation strategies are valuable for designing future high-performance industrial PEMFCs.

Highly Active and Stable Bimetallic Ordered Catalysts for Oxygen Reduction Reaction Improvement in Polymer Exchange Membrane Fuel Cells

Demand for replacing the Pt catalyst in proton exchange membrane fuel cells (PEMFCs) has increased because Pt metal is rare and high cost. The most reasonable way is synthesizing Pt-base alloy using transition metals such as Co, Ni, Fe, and Mo. The Pt-based alloy catalysts exhibit excellent catalytic activity by creating a synergistic effect through the interaction between Pt and the transition metals. Here we present the best PtNi alloy composition and maximize the performance of the oxygen reduction reaction (ORR) activity in fuel cells by annealing the alloy under a hydrogen atmosphere. The Pt7Ni3/C catalyst indicated a higher ORR activity than other compositions due to different structural changes, and the annealing catalysts at 700 °C under an H2 atmosphere improved the electrochemical activity and stability. The heat treatment increased the conductivity by reducing oxygen bonding as well as changing the structure into an ordered face-centered tetragonal (FCT) structure with good activity. The result of these studies provides a new way to develop high-performance and low-cost catalyst materials for fuel cells.

The energy efficiency of an extended range unit involving a polymer exchange membrane fuel cell stack

This article presents the results of experimental investigations on an advanced model of a polymer exchange membrane fuel cell (PEMFC) stack designed to serve as a charging unit for electric vehicle batteries or off-grid distributed power sources. The assembled 720 W PEMFC stack comprises two 360 W modules that can be electrically connected in series or parallel. A liquid cooling system for the PEMFC stack has also been constructed. The dependencies – voltage (U) versus current (I) and current (I) versus electrical power (P) – for single modules, as well as for the electrically connected two-module PEMFC stack, are determined. Additionally, the hydrogen utilization versus the electrical power (P) of the PEMFC stack is examined. The electrical efficiency of the PEMFC stack varies between 42% and 50%, depending on the electrical power. An adjustable DC/DC converter, operating in two modes (step-down or stepup), is proposed as a device to integrate a lithium-ion (Li-ion) battery pack with approximately 720 W PEMFC stack. The electrical architecture of the integrated system, comprising the PEMFC stack, DC/DC converter, and Li-ion battery pack, is investigated and discussed in this paper. It was found that the electrical efficiency of the proposed DC/DC converter varies depending on the electrical power, reaching a peak efficiency of 95%– 98%. The environmental benefit, in terms of reducing CO2 emissions when charging the battery, was also identified.

Thermodynamic study of integrated proton exchange membrane fuel cell with vapour adsorption refrigeration system

With the rising usage of fossil fuels, there is an urgent need to develop new technologies specifically based on renewable energy sources to power the vehicles running on fuel. A fuel cell is an electrochemical cell that is used to convert the chemical energy of a fuel directly to electric power. Fuels cells possess advantages such as smaller size, high efficiency, silent operation, etc. However, there can be significant variations in the size and power output of the fuel cells depending upon the application. The focus of this paper is to estimate the performance of an integrated system comprising of Polymer Exchange Membrane Fuel cell (PEMFC) and vapour adsorption refrigeration system to produce electric output and cooling effect simultaneously. The adsorption system in this study is based on activated carbon and methanol combination. The effect of operating parameters such as the operating temperature, current density and evaporator temperature on the energy and exergy efficiency of the system is presented. The study shows a remarkable improvement in the performance of the integrated system compared to PEMFC alone. The results show that the system energy and exergy efficiency decrease as the current density value increases. Maximum system energy and exergy efficiency of 63.01% and 29.88% are achieved. In addition, a maximum energy efficiency of 65.39% was reported at an evaporator temperature of 5 °C and a current density of 0.8 A/cm2.

A 2D Multi-Layer Model to Study the External Magnetic Field Generated by a Polymer Exchange Membrane Fuel Cell

An original innovative two-dimensional (2D) multi-layer model based on the Maxwell–Fourier method for the diagnosis of a polymer exchange membrane (PEM) fuel cell (FC) stack is presented. It is possible to determine the magnetic field distribution generated around the PEMFC stack from the (non-)homogenous current density distribution inside the PEMFC stack. Analysis of the magnetic field distribution can indicate whether the FC is healthy or faulty. In this way, an explicit, accurate and fast analytical model can allow the health state of an FC to be studied. To evaluate the capacity and the efficiency of the 2D analytical model, the distribution of local quantities (i.e., magnetic vector potential and magnetic field) in a PEMFC stack has been validated with those obtained by the 2D finite-element analysis (FEA). The comparisons demonstrate excellent results both in terms of amplitude and waveform. The validation of this 2D analytical model is essential for the subsequent generation of an inverse model useful for the diagnosis of a PEMFC.

Review of Hydrogen Based Fuel Cells Energy Storage Systems

This paper presents a review of the hydrogen energy storage systems. Most developed countries have turned to search for other sources of renewable energy, especially solar energy, and hydrogen energy, because they are clean, environmentally friendly, and renewable energy. Therefore, many countries of the world began to accept the inevitability of shifting to an economy based on hydrogen as a future fuel. Among the difficult challenges in this transformation are the methods of storing electrical energy in fuel cells and storing hydrogen, as the race of large energy companies has begun to provide solutions to develop many types of fuel cells, given that they are the biggest challenge to energy generation and storage. This paper presents a review of fuel cells including Energy Storage Using Hydrogen Produced from Excess Renewable Electricity, as well as to cover the storage system includes three main components: electrolysis, fuel cell, and a hydrogen buffer tank. We will discuss the different types of fuel cells, such as: Alkaline Fuel Cells (AFC), Polymer Exchange Membrane Fuel Cell (PEMFC)...etc.) along with the different application of fuel cell hydrogen energy storage, we will also investigate some case studies of the hydrogen energy storage and main opportunities and challenges of the implementation.

(Invited) Effects of Support Mesoporosity on Pt Dissolution in PEM Fuel Cells

Interest in hydrogen as an energy carrier continues to grow due to the high demand for clean and sustainable, energy sources in the global energy market. Polymer exchange membrane fuel cells (PEMFCs) convert the chemical energy of hydrogen to electricity and have great potential as power sources for automotive applications. A key challenge in the development of cost-efficient and reliable PEMFC electrodes is catalyst layer durability. Typically, PEMFC cathodes comprise Pt-based electrocatalysts supported on high-surface-area carbons. It has been previously shown that the morphology and surface chemistry of carbon supports play significant roles in modulating both the activity and stability of Pt-based catalysts.Here, we will present our recent efforts to investigate the effects of the porous structures and surface properties of different mesoporous carbon powders on Pt dissolution in PEMFC cathodes. Using atomic layer deposition (ALD), we fabricate cathodes by depositing Pt nanoparticles of uniform sizes and mass loadings onto mesoporous carbon supports with varying pore sizes and surface areas. We then evaluate the beginning-of-life and end-of-life performance of these cathodes after accelerated Pt dissolution tests under single cell conditions, while comparing them to a microporous Ketjenblack-based cathode as a benchmark. Based on our findings, we discuss new insights into the underlying mechanisms for Pt dissolution within the porous structures of mesoporous carbon supports.

Prediction of the monthly cost of energy usage by PEMFC at housing in North Sumatra Province, Indonesia

The development of renewable energy is increasing nowadays. Besides, the development of energy conversion systems that can work at high efficiency also increases along with the decreasing availability of fossil energy. The fuel cell is an electrochemical device that converts chemical reaction energy directly into direct current electrical energy. The use of fuel cells as power generating in housing has also increased rapidly, especially in developed countries. This study aims to develop a model and simulation for the Polymer Exchange Membrane Fuel Cell (PEMFC) system with a working temperature of 165 °C) using Aspen Plus simulation. In this analysis, the model and simulation developed are used to predict the amount of fuel needed when used in housing as an electricity generator and obtain a monetary value for the monthly fuel procurement. The PEMFC system is designed to generate power up to 0.60 kW by consuming hydrogen fuel with a current density of 0.02 A/cm2. The hydrogen consumed by the PEMFC system is around 0.030 kg/hour, with a monthly cost of hydrogen consumption by the system is Rp. 2,052,000. Meanwhile, the monthly electricity from the national grid (PLN) bill costs around Rp. 569,261 (in the year 2019). In comparing the energy bill, at the moment, the fuel cost for PEMFC as a power generation system is much more expensive than PLN’s electricity consumption costs due to the high hydrogen fuel cost.

Energy Conversion and Storage in Fuel Cells and Super-Capacitors from Chemical Modifications of Carbon Allotropes: State-of-Art and Prospect

Abstract Despite being generated from the same element and having some of the properties commonly shared, each type of carbon allotrope possessing divergent shape confers unique and distinguishable physicochemical properties, thereby making them attractive for a wide range of potential applications. Moreover, research progress has allowed for further tailoring the properties in a controlled way to design more fascinating and aesthetically pleasing architectures with outstanding materials properties. In fact, some chemically modified carbon allotropes and their products have shown significant promise to solve a number of major issues in polymer exchange membrane fuel cells (PEMFCs) and supercapacitors (SCs) such as efficient low Pt loaded oxygen reduction reaction (ORR) catalysts, carbon allotrope-based proton conductors for PEMFC electrolyte, carbon monoxide (CO) tolerant anode catalysts for PEMFC, and carbon allotropes-based SC electrodes. The tremendous progress made in carbon-based materials facilitates those technologies more realistically towards large-scale implementation in terms of increasing the stack power density and reducing cost. In this view, this review will provide a thorough insight for researchers into the use of carbon allotropes and relevant products for PEMFCs and SCs.

STEADY-STATE MODELLING OF PEM FUEL CELLS USING GRADIENT-BASED OPTIMIZER

The accuracy of fuel cell (FC) models is important for the further numerical simulations and analysis at several conditions. The electrical (I-V) characteristic of the polymer exchange membrane fuel cells (PEMFCs) has high degree of nonlinearity comprising uncertain seven parameters as they aren’t given in fabricator's datasheets. These seven parameters need to be obtained to have the PEMFC model in order. This research addresses an up-to-date application of the gradient-based optimizer (GBO) to generate the best estimated values of such uncertain parameters. The estimation of these uncertain parameters is adapted as optimization problem having a cost function (CF) subjects to set of self-constrained limits. Three test cases of widely used PEMFCs units; namely, SR-12, 250-W module and NedStack PS6 to appraise the performance of the GBO are demonstrated and analyzed. The best values of the CF are 0.000142, 0.33598, and 2.10025 V2 for SR-12, 250-W module and NedStack PS6; respectively. Furthermore, the assessment of the GBO-based model is made by comparing its obtained results with the experiential results of these typical PEMFCs plus comparisons to other methods. At a due stage, many scenarios as a result of operating variations in regard to inlet regulation pressures and unit temperatures are performed. The copped reported results of the studied scenarios indicate the effectiveness of the GBO in establishing an accurate PEMFC model.

Deep Reinforcement Learning Guided Cascade Control for Air Supply of Polymer Exchange Membrane Fuel Cell

The power consumption of an electric air compressor becomes the major parasitic energy waste leading to the deterioration of net efficiency of the fuel cell system (FCS). Optimal control of the oxygen excess ratio (OER) is recognized as a feasible way to resolve the paradox of stack health and system efficiency. Herein, a novel cascade control scheme that leverages model predictive control (MPC), fuzzy Proportion Integral control (FPI), and deep reinforcement learning technique is proposed to regulate the OER for a 75 kW FCS. The master‐slave control structure is adopted, and a reference air mass flow rate and the motor voltage of the air compressor are taken as control targets, respectively. A deep deterministic policy gradient (DDPG) algorithm is used as a parameter tuner for MPCProportion Integral (PI) controller. The results indicate that both MPCFPI and DDPGMPCPI can achieve better control performance indices in comparison to classic controller under step response and a typical driving cycle. The DDPG‐guided cascade controller is also capable of regulating the OER tracking error and the derivative of rotation speed of the air compressor, which reveals the potential for extending the longevity of the FCS.

A Finite Element Method Study of Polymer Exchange Membrane Fuel Cell End Plate Materials by Using Arcan Specimen

In the current days, fuel cells are more preferred to generate electricity due to their positive sides. Because, if they use hydrogen and oxygen as fuel, they only produce electricity, heat, and water. This property of fuel cells is significant because of preventing environmental and chemical pollution so, they contribute to the environment positively. In addition, they have more positive points such as no moving or rotating parts. Therefore, they are no required for mechanical maintenance and not make noise. Besides, they can be used used in a wide range of areas as mobile and stationary power sources for electricity generation. There are many fuel cell types but, proton exchange membrane fuel cell (PEMFC) is more common than the other fuel cell types. It consists of parts such as an endplate, bipolar flow plate, gas diffusion layer, catalyst layer, and membrane. End plates are located on the outer side of PEMFC and hold together its stacks. In the design of the endplates, the state of fracture energy should be considered in the different loading conditions. Because the material may fail if it is designed only by the strength of materials concepts. This paper investigated pure mode I, pure mode II and mixed mode fracture energy behavior of different materials numerically by using Arcan specimen.

Jellyfish search algorithm for extracting unknown parameters of PEM fuel cell models: Steady-state performance and analysis

In this paper, a novel attempt to employ the Jellyfish search algorithm (JSA) for solving parameters’ identifications problem of polymer exchange membrane fuel cells (PEMFCs) model is addressed. The minimization of the sum of squared errors (SSEs) between measured and estimated voltage dataset points define the fitness function to be optimized by the JSA subject to set of self-constrained inequality bounds. Three test cases are demonstrated complete with necessary verifications, comparisons and subsequent discussions. It can be quantified here that the best cropped values of SSEs are equal to 0.011699, 0.33598 and 2.14570 V2 for BCS 500-W module, 250-W stack and NedStack type PS6 unit; respectively. It can be confirmed that the maximum value of percentage voltage biased error is ±1% for all test cases under study. In addition, various performance measures are made to signify the robustness of the cropped results. At a later stage, various operating principal characteristics under changeable temperatures and varied regulating pressures are illustrated. It can be established that the JSA proves its ability to tackle this problem competently compared to others.

Design, Development, and Performance of a 10 kW Polymer Exchange Membrane Fuel Cell Stack as Part of a Hybrid Power Source Designed to Supply a Motor Glider

A 10 kW PEMFC (polymer exchange membrane fuel cell) stack consisting of two 5 kW modules, (A) and (B), connected in series with a multi-function controller unit was constructed and tested. The electrical performance of the V-shaped PEMFC stack was investigated under constant and variable electrical load. It was found that the PEMFC stack was capable of supplying the required 10 kW of electrical power. An optimised purification process via ‘purge’ or humidification, implemented by means of a short-circuit unit (SCU) control strategy, enabled slightly improved performance. Online monitoring of the utilisation of the hydrogen system was developed and tested during the operation of the stack, especially under variable electrical load. The air-cooling subsystem consisting of a common channel connecting two 5 kW PEMFC modules and two cascade axial fans was designed, manufactured using 3D printing technology, and tested with respect to the electrical performance of the device. The dependence of total partial-pressure drop vs. ratio of air volumetric flow for the integrated PEMFC stack with cooling devices was also determined. An algorithm of stack operation involving thermal, humidity, and energy management was elaborated. The safety operation and fault diagnosis of the PEMFC stack was also tested.

Thermal integration of Proton Exchange Membrane Fuel Cell with recuperative organic rankine cycle

The increased usage of fossil fuels in today's world is leading to an energy crisis and is having a catastrophic impact on our surroundings. There is an immediate need for the development of new, clean and renewable sources of energy especially to power the fuel driven vehicles to decrease the level of carbon footprint around the world. Fuel cells continue to produce power by undergoing a chemical process unlike conventional combustion technology to convert hydrogen-rich fuel into electricity as long as a fuel source is provided and need not be periodically recharged like batteries. The individual fuel cells can be coupled or compiled together to form stacks that can be combined into larger systems and can be scaled based on the requirement. Fuel cell systems have numerous applications from combustion engine replacements for electric vehicles and portable systems for recharging batteries of several devices to large-scale, multi-megawatt installations providing electricity directly to the utility grid. They vary greatly in their size and power output produced. In the present study, thermal integration of Polymer Exchange Membrane Fuel Cell (PEMFC) with Recuperative Organic Rankine Cycle (RORC) is analyzed. The PEMFC has a higher efficiency when compared to conventional energy conversion devices ranging between 40 and 60% and can also be maximized by using regeneration techniques. High temperature PEMFCs also release heat at a useful temperature of 423 K which can further be utilized to extract useful work to improve the overall efficiency of the fuel cell. A further study and analysis of the various processes of thermal regeneration techniques to improve the efficiency of a fuel cell is carried out.

Anode Monitoring By Electrochemical Impedance Spectroscopy in Polymer Electrolyte Membrane Fuel Cells

Although widely used to study the operation of Polymer Exchange Membrane Fuel Cells (PEMFC), Electrochemical Impedance Spectroscopy (EIS) remains a complex tool: experimental data are somewhat delicate to interpret because of the wide range of physical phenomena occurring in Membrane Electrode Assemblies (MEA) and in the flow field plates. Therefore, impedance models are often based on oversimplified equations or conversely, include too many correlated parameters. A typical example of the complexity of the phenomena governing fuel cell electrical behavior are the oscillations of oxygen concentration resulting from the measuring signal, that propagate along the gas channels and makes more difficult the interpretation of the low frequency loop [1, 2, 3]. In addition, most of the impedance models assume Fickian oxygen diffusion although, at least in fuel cells fed with air, Stefan-Maxwell equations should be used as in most stationary models [4, 5]. In this regard, oxygen diffusion and thus the low frequency impedance are strongly dependent on the overall convective flux and as a result, on water management [6].However, due to the characteristic times of oxygen diffusion, these limitations do not apply to the high frequency region of the impedance spectra. The high frequency impedance of a PEMFC remains mostly governed by the cathode [7] but at least in some cases, considering the anode in the Electrical Equivalent Circuit (EEC) is necessary to improve the quality of the fit of the model to the experimental data (Figure). Since the anode has an impact on fuel cell impedance, this means that it becomes possible to monitor its ageing while performing Accelerated Stress Tests (AST). Since most of FC lifetime issues presumably originate from the cathode [8, 9] anode degradation has been rarely studied in the literature. Nevertheless, Schwämmlein et al. showed recently that it may be significant in the case of repeated start-up and shut-down - because of potential cycling - and have a measurable impact on FC performance [10].In this work, we performed AST combining potential and humidity cycles to be as representative as possible of the stressful conditions encountered by the FC in real operating conditions. Commercially available MEA with an initial voltage of the order of 0.7 V at 0.5 A/cm² showed a drop in performance comprised between 400 and 900 µV/h, and a significant degradation of the anode operation was observed by EIS (Figure), confirmed by an increase of its local potentials, and linked to Pt ElectroChemical Surface Area (ECSA) losses. Post-mortem physico-chemical analysis of MEA will be carried out to bridge the decrease of performance with the degradation mechanisms occurring at the anode catalytic layer. Note that these tests were carried out using a 30 cm² segmented cell with 5 straight parallel gas channels [11] (30×1 cm² active area) and that its overall performances may be lower than with regular cells.

The Role of Lone-Pair Electrons in Pt-N Interactions for the Oxygen Reduction Reaction in Polymer Exchange Membrane Fuel Cells.

Invited for this month's cover is the group of Jaeyoung Lee at the Gwangju Institute of Science and Technology (GIST). The cover image shows how the lone-pair electrons on N atoms could play a role in both uniform nucleation of Pt nanoparticles and facile oxygen reduction reaction (ORR). Strong Pt-N interaction based on π-backdonation improves not only the activity of the ORR but also the durability in the polymer exchange membrane fuel cells. The Full Paper itself is available at 10.1002/cssc.201903403.

Front Cover: The Role of Lone‐Pair Electrons in Pt–N Interactions for the Oxygen Reduction Reaction in Polymer Exchange Membrane Fuel Cells (ChemSusChem 7/2020)

The Front Cover shows how the lone-pair electrons of surface atoms could play a role in both uniformly distributed growth of functional platinum nanoparticles and improved oxygen reduction reaction through facile dissociation of oxygen molecules in fuel cells. More information can be found in the Full Paper by K. Ham et al. on page 1751 in Issue 7, 2020 (DOI: 10.1002/cssc.201903403).