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Fuel cell systems: efficient, flexible energy conversion for the 21st century
Abstract
At the beginning of the 21st century, fuel cells appear poised to
meet the power needs of a variety of applications. Fuel cells are
electrochemical devices that convert chemical energy to electricity and
thermal energy. Fuel cell systems are available to meet the needs of
applications ranging from portable electronics to utility power plants.
In addition to the fuel cell stack itself, a fuel cell system includes a
fuel processor and subsystems to manage air, water thermal energy, and
power. The overall system is efficient at full and part-load, scaleable
to a wide range of sizes, environmentally friendly, and potentially
competitive with conventional technology in first cost. Promising
applications for fuel cells include portable power, transportation,
building cogeneration, and distributed power for utilities. For portable
power a fuel cell coupled with a fuel container can offer a higher
energy storage density and more convenience than conventional battery
systems. In transportation applications, fuel cells offer higher
efficiency and better part-load performance than conventional engines.
In stationary power applications, low emissions permit fuel cells to be
located in high power density areas where they can supplement the
existing utility grid. Furthermore, fuel cell systems can be directly
connected to a building to provide both power and heat with cogeneration
efficiencies as high as 80%
... Inside a fuel cell, hydrogen from fuel reacts with oxygen from air and produces water plus electricity as output. This reaction can be understood by equation (1) [73]. ...
... Chemical reactions at anode and cathode are given by (2) and (3), respectively [73] ...
On board energy management system for Electric Vehicle (EV) defines the fuel economy and all electric range. Charging and discharging of energy storage devices take place during running as well as stand-still conditions. Battery-alone EV suffers from range anxiety, current drain during peak power demand and less battery life. It depends on the grid for charging and thus the increasing popularity of EV is increasing burden on the grid. Different energy storage devices are available which could be used on board to form a hybrid energy storage system. Batteries, Ultra-capacitors and fuel cells are some of them. Such a system will act as a stress reduction factor and increase the battery life. In this paper, a detail literature review of various energy storage devices that can be used in EV is presented. A comparative study of various topologies available for this purpose is also presented. Finally, a detailed review of Energy Management Strategy (EMS) is presented with current trends and research gaps i.e., challenges.
... Positive ions reach the tip of the cathode via electrolyte and allow to pass only positive charges [55][56][57]. Negative ions unite with positive charges, reach the anode's end, and pass to the cathode side via an external circuit [44,58,59]. Due to the flow of these electrons in the external circuit, Representation of multi-input DC-DC power converter in HEVs electricity is generated. ...
... Positive charges are combined with the electrons passing to the cathode side and O 2 to produce heat and water [45,[60][61][62]. The chemical reactions are governed by the following equations [42,43,59]: ...
In the last few decades, the utilization of fuel cells (FCs) in the automotive industry has created much attention due to easy use, modular structure, and higher efficacy. In the future, technological evolutions reveal that FCs driven electric vehicles (EVs) will grow at a rapid pace and will become an excellent alternative to conventional vehicles. This paper discusses a detailed topological classification of the FC-based hybrid electric vehicle (FCHEV). In these FCHEVs, one of the critical elements is the DC-DC power converter unit. The hybridization of FCs with the other power sources requires more converter units that make the system complex. A multi-input DC-DC power converter is used to connect more than one energy source to reduce the system's complexity and improve the overall system efficacy. In this survey, numerous articles have been considered and examined vividly. An assessment of present and future scenarios of FCs based power source topologies and multi-input DC-DC power converter topologies used in HEV is presented. This survey provides a deep insight into the topic to the researchers and engineers working in this field.
... Hydrogen is a form of energy storage with great potential in the renewable energy field due to its near-zero greenhouse gas emission and high efficiency [6]. Hydrogen can be collected using an electrolyzer to break up water molecules and isolate the hydrogen atoms. ...
... The overall saving that can be achieved using microwave technology also depends on how the electric energy is generated. A fuel cell plant is more efficient than a com- bustion plant [7]. Cogeneration enhances the efficiency of the combustion and fuel cell plants (Table 1). ...
For the agricultural sector to develop sustainably in the future, progress toward more environmentally friendly technologies and methods is crucial. It is necessary to increase output while reducing the demand for energy, agrochemicals, and water resources. Although greenhouses can be utilized successfully for this purpose, significant technical advancements are required, especially when it comes to heating, to lower the use of fossil fuels and boost energy efficiency. Microwaves can warm plants without heating the entire greenhouse volume, which takes a significant amount of energy to compensate for heat loss in the outdoor environment. In this paper, through a thorough examination of the state of the art, a general overview of novel greenhouse heating systems based on radiation is reported. First, the strengths and weaknesses of microwave heating are discussed, and finally, the use of microwaves for soil sterilization is examined. All outcomes suggest these irradiation-based technologies can contribute significantly to energetically sustainable agriculture; moreover, they can be used to increase plant comfort.
... The fuel cells, for example, are regarded as a viable alternate for small-and medium-scale distributed renewable energy systems powered by electrochemical energy storage and conversion devices, such as rechargeable batteries [12,13]. Electrochemical technologies offer a widespread variability of energy conversion devices, but fuel cells are the most compelling among them [14]. Chemical energy can be directly and spontaneously transformed into electricity by these systems [15]. ...
... Fuel cells may be utilized in various ways: They may replace the grid or provide supplemental power, serve as both primary and secondary power, or provide standby power [10][11]. Mobile power production has been driven primarily by the need for higher quality, higher density, and higher time performance resulting from increased product development (CD players, mini-disk players, notebook computer systems, and cellphones). ...
Functional membranes are used in food processing, sensor technology, medical and biomedical devices, desalination, waste water treatment, CO2 capture, energy production and energy storage, optoelectronics etc. The book reviews recent advances in the field and discusses challenges and perspectives.
... Therefore, the use of BESs to produce sustainable energy is a far safer long-term strategy, which avoids the use of conventional technologies that cause damage to the environment. BESs such as microbial electrochemical systems (MES) undoubtedly produce electricity using reactive fuels such as alcohol, H 2 , etc, avoiding greenhouse gas emissions [89]. MESs are an economical option because they generate electricity from wastewater (using bacterial activity). ...
This chapter discusses the fundamental classification of bioelectrochemical systems (BESs) based on the energy liberated and energy required (microbial electrolysis and microbial electrosynthesis) and their real-time applications, e.g. biosensing (BOD sensors, IoT sensors, etc), bioremediation, and scalable production of biohydrogen and other valuable products (organic acids, alcohol, bioplastics, etc), including scalability. In addition, the technoeconomic and sustainability assessments of BESs are also elaborated upon.
... Recent years have also witnessed an increase in the demand for hydrogen as the chemical energy vector to obtain electricity from fuel cells [5], which together with hydrogen technologies are the most promising solutions that address both energy security and environmental concerns, in addition to being more energy-efficient than diesel or internal combustion engines [6,7]. Accordingly, much attention has focused on hydrogen generation by the steam reforming of alcohols to solve the problems entailed in the steam reforming of a fossil fuel (e.g. ...
In a previous study, we reported that hydrogen generation can be achieved quite efficiently from seawater and contaminated waters at low temperatures using a microwave-driven hydrogen production (MDHP) process and waste activated carbon as the microwave absorption heating element (MAHE). However, the problem with this method is that activated carbon (a heat source from the microwaves) is used in the decomposition of water in which the quantity of activated carbon continues to decrease in parallel with the evolution of hydrogen. This problem has been resolved in this study by using magnetite as a novel MAHE component at low temperatures; the energy-saving thermochemical steam reforming reaction was performed with a mixed water/ethanol solution, for which results showed a maximum hydrogen generation yield somewhat greater than 80%. No hydrogen evolved in the thermochemical steam reforming process upon heating the magnetite at 350 °C in a conventional electric furnace, in contrast to the case where hydrogen was generated in yields greater than 40% by heating at 350 °C with microwaves. The rate-determining energy required for hydrogen generation is evidently heat, as evidenced by the formation of microwave-generated microscopic high-temperature fields (hot spots) at an estimated temperature of ca. 760 °C at the magnetite surface, a result of microwave heterogeneous microscopic thermal effects (MHMEs), and this even if the average temperature of the magnetite bulk were 350 °C.
... • The low operating temperature ranges from (50-250) 8C for PEMFC, AFC and PAFC, and high operating temperature in the range of (650-1000) 8C like MCFC and SOFC. Based on the review conducted [24]- [25], the main advantages, disadvantages and suitability of the application of all fuel cells are briefly described in the reference. ...
In the near future, reduce emissions from the combustion of the ship’s main engine by increasing the propulsion efficiency of ships that are already operating and/or optimizing ship designs during the design process. The International Maritime Organization (IMO) has introduced stringent regulations to reduce GHG emissions for the global shipping industry. Another solution to reduce emissions is to use alternative renewable energy and clean. This paper will describe what energy is used for ship propulsion nowadays and other alternative energy sources that can be used for main engines, additional or hybrid power. Wind energy, solar PV, and fuel cells are renewable energy options for small ships’ main propulsion, navigation, lighting, and electronic devices. Furthermore, the method used for writing this paper is collecting the best paper and selecting technology alternatives energy that is possible to install on the ship.
... Therefore, in that sense, fuel cells are different from general batteries. 5,6 Two electrodes, named the anode and the cathode, are contained in a fuel cell where a chemical reaction occurs. The anode and the cathode are steeped in an electrolyte used to transport protons. ...
Microfluidic fuel cells (MFFCs) are performing increasingly important roles in production and life, such as electronic products, sensors and real‐time equipment. The microfluidic electrochemical fuel cell (MFEFC) is a significant type of MFFC that has attracted recent global attention. Compared to the other two types, biofuel cells (MFBFCs) and photocatalytic fuel cells (MFPFCs), MFEFCs can be used in a broader range of applications and are less susceptible to external environment. This paper mainly discusses the recent progress of MFEFCs, including catalyst, fuel, electrode, oxidant, design, fabrication, model and performance. The paper summarized the latest research results and practical applications through the above aspects. The authors sincerely hope that this paper will be useful to researchers in the field. Finally, we summarize the article and outline the potential future development and applications of MFEFCs. © 2022 Society of Chemical Industry (SCI).
... In the 1990s, as one of the important ways to mitigate environmental pollution and demand for oil, the FCEV technology received enormous attention. In 1995, Times magazine listed the FCEV as the first of ten high and new technologies in the 21st century [31,32]. The global major automobile manufacturers have invested a lot of manpower and resources in developing FCEVs and energy conversion devices that can convert chemical energy stored in fuels to electricity and heat electrochemically with high energy efficiency have witnessed tremendous development [33][34][35]. ...
The automotive industry consumes a large amount of fossil fuels consequently exacerbating the global environmental and energy crisis and fuel cell electric vehicles (FCEVs) are promising alternatives in the continuous transition to clean energy. This paper summarizes the recent development of fuel cell technologies from the perspectives of the automobile industry and discusses current bottlenecks hindering commercialization of FCEVs. Current status of the fuel cell technology, policies and market prospect of FCEVs, as well as recent progress of FCEVs are reviewed. Polymer electrolyte membrane fuel cells constitute the mainstream and most mature fuel cell technology for automobile applications. Hybridization with an auxiliary battery system will greatly boost the dynamic response of FCEVs. Hydrogen FCEVs have entered the preliminary commercialization stage since 2015 and the market share of FCEVs is expected to grow at a high rate. Challenges encountered by commercialization of FCEVs and future outlook are also discussed. Future efforts are expected to focus on solving problems such as the high cost of fuel cell stack production and maintenance, insufficient hydrogen supply facilities, insufficient reliability, slow cold start, safety concerns, and immature energy management systems of FCEVs. This review serves as a reference and guide for future technological development and commercialization of FCEVs.
... Hydrogen, as a fuel, is a high-quality, low-polluting fuel, and can be used for transportation subsytems is illustrated in Figure 3 [8]. ...
Alternative energy encompasses the newer, less obvious and smaller scale energy schemes as opposed to traditional schemes entrenched in fossil fuels, hydropower and nuclear energy. The paper puts an engineering and business perspective on the sources and the technologies for alternative energy development, seen in a global view and in the light of local sensitivity. The case for the drive to exploit alternative energy is put forward. Various schemes for alternative energy sources are described and an assessment given on the feasibility of the technology in Zambia. The best opportunities come from exploitation of solar and biomass energy sources.
Energy, which is an indispensable part of human life, is one of the most discussed issues on the world agenda today as it was in the past. The largest share of the world’s energy resources belongs to fossil fuels (coal, oil, natural gas). Due to the sustainability and emission problems of fossil fuels, interest in environmentally friendly and renewable energy sources is increasing day by day. In the field of aviation, the search for clean and environmentally friendly energy sources is one of the important issues. The fact that battery technologies cannot yet fully meet the needs of propulsion systems has pushed researchers toward hybrid energy sources. This search has led to the emergence of the concept of hybrid-electric aircraft. Hybrid-electric aircraft are supported by energy sources such as hydrogen, solar, and supercapacitor in addition to batteries. Depending on the purpose and structure of the aircraft, the appropriate energy sources are used at different hybridization rates.
Sulfonated polyether ether ketone (SPEEK) has been widely investigated in proton exchange membrane fuel cells (PEMFCs) due to its excellent thermal stability, chemical stability, and low cost compared with Nafion. However, excessive degree of sulfonation will easily lead to the decrease in thermal stabilities and mechanical properties of SPEEK membranes, which limits the enhancement of proton conductivity. In this work, a series of Schiff-base networks (SNWs) with different contents are in situ synthesized in the SPEEK membrane by a Schiff-base co-condensation reaction, and then, the composite membranes are soaked in sulfonic acid for further improvement of proton conductivity. The highest doping amount of the SNW filler in SPEEK can reach 20 wt %. High loading and low leaching rate of H2SO4 are easily achieved owing to the similar size between sulfuric acid molecules and micropores in SNW. Moreover, abundant amino and imine groups in SNW networks contribute to the anchoring of H2SO4 into the pores by acid-base interactions. The proton conductivity of the SPEEK/S-SNW-15 composite membrane can reach 115.53 mS cm-1 at 80 °C and 100% RH. Meanwhile, the composite membrane also exhibits satisfied stability and mechanical property.
Plastic is one of the most widely used materials in industries including packaging, building, and construction due to its lightweight, low cost, durability, and versatility. However, the mass production of plastics has exacerbated plastic pollution. Globally, plastic waste is predominantly incinerated, landfilled, or released into the environment; only 5–6% is recycled in the United States. Although conventional management protocols such as incineration and landfilling are evidently effective for plastic waste disposal, they are associated with significant environmental and societal challenges. In addition, most recycled plastic is downcycled, and thus does not provide sufficient incentive to use recycled materials instead of virgin materials. This review discusses thermo-chemical upcycling processes such as (catalytic) pyrolysis and heterogeneous catalysis. Furthermore, we present the recent progress in the thermo-chemical upgrading of single-type plastic waste, heterogeneous plastic mixtures, and post-consumer plastic waste obtained from different locations and, finally, suggest future research directions.
Beberapa teknologi sel bahan bakar akan segera menjadi alternatif yang terjangkau dan menarik untuk pembangkit energi tradisional. Teknologi energi terbarukan telah memicu minat luas dalam memberi daya pada tempat-tempat pedesaan dan menghasilkan daya terdistribusi, terutama selama beban puncak. Pembangkit listrik berbasis sel bahan bakar mendapatkan dukungan aplikasi di rumah dan pembangkit listrik terdistribusi karena kebersihan, portabilitas, dan kesesuaiannya untuk pembangkit listrik dan panas. Masalahnya tetap dalam mengembangkan antarmuka elektronik daya yang sesuai untuk membuat teknologi layak. Penelitian ini menyajikan pemodelan, simulasi, dan analisis eksperimental pembangkit listrik sel bahan bakar (FC) yang cocok untuk aplikasi stand-alone dan antarmuka microgrid/grid, menggunakan berbagai pengontrol seperti Kontroler PI PID dan Kontrol Logika Fuzzy. Inverter modulasi lebar pulsa satu tahap dipilih sebagai antarmuka daya listrik antara FC dan jaringan. Sebuah model matematis dibangun per unit sistem untuk menentukan batas daya dalam hal FC, konverter, dan parameter sistem daya. Model simulasi dibuat dalam lingkungan MATLAB, dengan metode kontrol diimplementasikan dalam kerangka referensi QD. Sebuah perbandingan dari tiga kontroler yang berbeda dibuat.
Microbial fuel cells (MFCs) are central to an emerging and significant approach that
converts chemical energy into electrical energy using bacteria that serve as catalysts.
Significant achievements in power density have been reported. However, MFCs have
not yet been implemented at a commercial scale due to their low energy production.
There are several reasons for this low energy production efficiency. Owing to their
sustainability, MFCs have been recognized as a viable technology for producing
energy and removing toxic pollutants from wastewater resources. In addition to a
proton exchange membrane (PEM),MFCs consist of two electrodes—an anode and a
cathode—the former of which is responsible for providing sufficient space for bacterial
growth and respiration in order to oxidize organic matter in wastewater and thereby
generate protons and electrons. The approach has attracted attention for its capacity
to generate renewable energy and treat wastewater simultaneously.Research on energy production through MFC technology has received great
attention. It is emerging as a promising approach which converts chemical energy
into electrical energy in the presence of a biocatalyst and simultaneously removes
toxic pollutants from water. The electroactive bacteria species degrade the organic
waste and the released electrons are passed from the organic waste to an electrode
for the generation of energy. Furthermore, the transportation of electrons from
bacteria to the electrode surface is an essential step for energy generation. Hence, the
poor transportation of electrons may greatly hinder the performance of MFCs. In
the last decade, several efforts have been made to improve electron transportation
between bacteria and electrodes which ultimately affects the efficiency of the MFCs.
To achieve this objective, a large variety of materials was used to fabricate different
improved extracellular electron transferable electrodes for high energy generation
and achieve excellent durability performance of MFCs.
This book covers the electrochemical performance of MFCs, the basic mechanisms,
affecting factors, required materials for high electrochemical performance,
and a comparison of MFCs with other bioelectrochemical approaches in terms of
energy generation. There is also significant coverage of the commercial status,
trends, and performance of MFCs.
Binary and ternary metal nitrides with d-block elements have been attracting attention as non-platinum oxygen reduction reaction (ORR) electrocatalysts. However, nitrides with f-block elements have not been explored as ORR catalysts, presumably because of their instability in an aqueous solution. By combining the stability of d-block metal nitrides in an alkaline solution and a high affinity toward OH⁻ of the f-block elements, novel ORR nitride catalysts in an aqueous alkaline solution would emerge. Herein, we synthesized novel manganese nitrides with rare-earth elements (Y, Er, Tm, Yb) via the self-combustion reaction and evaluated their ORR activities in an aqueous alkaline solution. Ytterbium-doped manganese nitrides with different compositions were synthesized by the combustion reactions between MnCl2-YbCl3 mixtures and NaNH2 powder. The lattice parameter of the synthesized nitrides increased with an increase in the concentration of rare-earth elements, and EDX exhibited the distribution of Mn and Yb on the nanometer scale. A significant change in the magnetic properties by adding Yb supported the incorporation of Yb into an MnN framework. The enhancement of the ORR activity and high affinity of OH⁻ on the surface were found in the nitride catalysts with ~1% Yb/Mn ratio. In addition, manganese nitrides containing small amounts of various rare-earth elements (Y, Er, Gd, Tm) with enhanced catalytic activities were also synthesized. This work provides new strategies for synthesizing metal nitrides with rare-earth elements, and for improving the ORR catalytic activities of metal nitrides by doping rare-earth elements.
This paper describes the characteristics of worldwide scientific contributions to the field of electric vehicles (EVs) from 1955 to 2021. For this purpose, a search within the Scopus database was conducted using “Electric Vehicle” as the keyword. As a result, 50,195 documents were obtained through analytical and bibliometric techniques and classified into six communities according to the subject studied and the collaborative relationships between the authors. The most relevant publications within each group, i.e., those related to the most publications, were analyzed. The result shows 104,344 authors researching on EVs in 149 different countries with 225,445 relations among them. Furthermore, the most frequent language in which these publications were written as well as the h-index values of their authors were analyzed. This paper also highlights the wide variety of areas involved in EV development. Finally, the paper raises numerous issues to consider in order to broaden knowledge about EVs, their efficiency, and their applications in the near future for the development of sustainable cities and societies.
Working of Proton Exchange Membrane Fuel Cell (PEMFC) can be described using Dynamic Gas Transport Model or Polarization Curve Model. Majorly, researchers have employed the latter for investigations on control applications. To carry out scientific advancements, one requires a suitable model of PEMFC for theoretical studies. In this review, several observed issues in recently reported works on the modeling of PEMFC are presented. After examining the modeling issues, the correct model of PEMFC with its detailed theoretical basis is derived. Further, to extract maximum power from PEMFC, one needs to employ a Maximum Power Point Tracking (MPPT) technique. Over time, many MPPT techniques for various applications have been reported. It was felt that a comprehensive review is required to allow the researchers to compare and choose the appropriate MPPT technique for a particular application. Therefore, various applicable MPPT techniques are reviewed and valuable outcomes have been drawn based on the significant parameters used to estimate the performance of a method. Therefore, this review paper has two following contributions to make. First, to provide the correct model of PEMFC, and second, to offer a comprehensive review of MPPT techniques. Further, based on the presented extensive review, this paper also provides future research directions and background for applying suitable MPPT techniques to utilize PEMFC efficiently.
This study aims to reduce the environmental impact of impurity adsorption systems on hydrogen production. Biomass is a carbon-neutral hydrogen fuel with a low environmental impact. However, during the production of biomass-derived hydrogen (biohydrogen), the hydrogen sulfide contained in the gasified biomass reduces the performance of fuel cells when hydrogen is used. Generally, hydrogen sulfide (H2S) is removed via impurity adsorption. However, common adsorbents such as metal oxides have a significant environmental impact. Therefore, adsorbents with lower environmental impacts are required. Thus, to improve metal depletion from the circular economy perspective, this study proposes using neutralized sediment, a waste product from the mining wastewater treatment, as an H2S adsorbent. In this study, we discuss the environmental impact of H2S adsorption systems that use neutralized sediments as adsorbents. Although the use of waste materials has a small environmental impact, it is necessary to consider the environmental impact of the inputs and outputs related to waste material generation based on life cycle assessment (LCA). Because fossil fuel-generated electricity and chemical neutralizers are input in mine wastewater treatment, the use of neutralized sediment may have a large environmental impact than the use of metal oxides from the viewpoint of LCA. Therefore, we quantitatively evaluated the environmental impact of neutralized sediment using LCA and investigated whether the environmental impact of using neutralized sediment is less than that of using metal oxides. In addition, it is not appropriate to include the production stage in the system boundary to meet the LCA standards because mineral water treatment, which is the production stage of neutralized sediment, is conducted whether neutralized sediment is utilized or not as an H2S adsorbent. Therefore, an LCA that does not include the production stage was also conducted to indicate the environmental benefit of waste utilization according to the actual situation. The amount of neutralized sediment used, which is calculated by the sulfur capture capacity, is necessary for the LCA calculation. However, the sulfur capture capacity of neutralized sediment has never been investigated. Hence, dynamic adsorption tests were conducted during gasification at low (40–120 °C) and high (200–300 °C) temperatures to investigate the sulfur capture capacity of the neutralized sediment in each temperature range. The results showed that the sulfur capture capacity of the neutralized precipitates was 2.28 (at 40 °C) and 5.73 (at 300 °C) g S/100 g sorbent. The results of the LCA, with and without including the neutralized sediment production process, based on the sulfur capture capacity, demonstrated that the use of neutralized sediment as an adsorbent improved the global warming potential (GWP) by 75.1% and 98.9%, respectively, compared with the use of metal oxides. In other words, this study quantitatively indicated that the use of neutralized sediment as H2S adsorbents has a smaller environmental impact than existing adsorbents and shows the importance of considering the actual situation in LCA for waste utilization.
In recent years, proton exchange membrane (PEM) fuel cell (FC; PEMFC) has been widely studied and gradually applied to vehicle power supply, portable supply, communication base station backup, emergency power supply, and so on. Especially in new energy vehicles, PEMFC has absolute advantages and a broad market. PEM, which is the core component of PEMFC, has a close correlation between its property and the performance of FC. Therefore, developing excellent PEMs is the focus of researchers. Metal–organic frameworks (MOFs) composed of metal ions/clusters and organic ligands have attracted extensive attention in the field of proton conduction. The hybrid membranes formed by MOFs and polymers show excellent performances and design concepts, which have great prospects in commercial application. This paper summarizes the research progress of MOFs‐based hybrid membranes as PEMs applied in hydrogen–oxygen FCs and direct methanol FCs, in which the different polymers used as substrates are also summed up. Recent advances in metal–organic frameworks (MOFs) as a versatile platform for proton conduction in the field of MOFs‐based proton exchange membranes (PEMs) for fuel cells are summarized in this review. Furthermore, the challenges, future trends, and prospects of MOF materials for PEMs are also discussed.
High voltage conversion with a continuous input and output current is the prime requirement for electric vehicles and renewable energy applications. In this paper, a new topology based on the Cuk converter is proposed to meet the high step-up gain, reduced switch stress, and continuous input current requirements. The topology is derived from the Cuk converter by using two switches, three inductors, a voltage-lift capacitor, and switched-capacitors. When compared to conventional converters, the proposed converter achieves a high step-up gain with reduced switch stress. Since the topology does not consist of a coupled inductor or transformer structure, voltage spikes during the turnoff process are eliminated. In addition, by simply varying the duty ratio of the two switches, a wide output voltage range is possible. The duty cycle and the switching pulses for the two switches are identical. Hence, the operation and control are simple. To analyze the topology, the continuous conduction mode of operation, voltage, and current stress of the devices, as well as an efficiency analysis are discussed. Finally, a 690 W prototype is implemented to experimentally examine and investigate the proposed converter.
The flow channel structure affects the fluid flow, gas diffusion, and electrochemical reactions for proton exchange membrane fuel cell (PEMFC). In this work, the flow channel structure is modified to improve the performance of PEMFC by adding streamlined blocks. First, four different imitated water-drop (IWD) blocks installed in the flow channel are designed based on the low resistance and high speed of streamline shape. Then, the different optimal imitated water-drop block arrangement spacing in the flow channel is investigated for PEMFC. Finally, the net power of the flow channel with optimal imitated water-drop shape and arrangement spacing is compared with the basic straight channel and trapezoid channel. Results show that the fourth imitated water-drop block has the highest net power when installed in the flow channel. Furthermore, the mass transport performance is further improved with the block spacing decreasing. The net power of the optimal imitated water-drop block channel with 2 mm block spacing is higher than that of the basic straight channel and the trapezoid channel. Therefore, the streamlined imitated water-drop blocks installed in the flow channel for PEMFC can strengthen the gas transfer capability, accelerate the electrochemical reaction, and obtain the better net power.
Modular process intensification offers the potential to realize step changes in process economics, energy efficiency, and environmental impacts by developing innovative process schemes and equipment to synergize multifunctional phenomena and/or to maximize multi-scale driving forces. This chapter provides an overview of the evolution of PI definitions and fundamental principles. A number of representative modular process intensification technologies and their industrial applications will also be introduced for advanced separation, advanced reaction, hybrid reaction/separation, and dynamic/periodic systems, etc.
This PhD thesis investigates the synthesis, structural characterization and oxygen reduction reaction (ORR) activity of Fe-N-C catalysts and composites of Fe-N-C and manganese oxides, and their application at the cathode of anion exchange membrane fuel cells (AEMFCs). Compared to proton exchange membrane fuel cells (PEMFCs), where platinum is today needed to reach high performance, AEMFCs hold the promise to reach high performance without precious metals in their catalysts. While Fe-N-C catalysts are currently investigated as an alternative to Pt/C for PEMFC cathodes, they suffer from lower activity and lower durability in the acidic medium of PEMFCs. In contrast, both the ORR activity and stability of Fe-N-C catalysts can be expected to be significantly improved in AEMFC.This PhD work demonstrates the high activity, stability and durability in alkaline medium of Fe-N-C catalysts with atomically-dispersed FeNx sites. They were prepared from a mix of ZIF-8 and iron salt, pyrolyzed in argon (Fe0.5-Ar) and then ammonia (Fe0.5-NH3). The activity was measured in a rotating disk electrode (RDE) and in AEMFC, while the stability was measured in RDE and in operando with mass spectroscopy (ICP-MS) coupled with a scanning flow cell, in both acid and alkaline media. The latter setup was used to measure Fe dissolution in operando. It was evidenced that, in oxygenated acid electrolyte, the iron leaching rate of the most active Fe-N-C catalyst (Fe0.5-NH3) is 10 times faster compared to the less active Fe0.5-Ar. This explains the reduced stability of ammonia-treated Fe-N-C catalysts in operating PEMFC. In contrast, in alkaline medium, very little demetallation was observed even for Fe0.5-NH3. This was correlated with almost unchanged activity after load cycling in RDE. The nature of the active sites was investigated with X-ray absorption spectroscopy, including in operando measurements.Then, to minimize the amount of peroxide species during ORR on Fe-N-C, different manganese oxides were synthesized and their activity for ORR and hydrogen peroxide reduction reaction (HPRR) were evaluated, while operando manganese dissolution was investigated with ICP-MS. It was found that even the most stable Mn-oxide, Mn2O3, leached a significant amount of Mn during ORR in alkaline medium. It was further demonstrated that the Mn leaching is associated with hydrogen peroxide produced during ORR. Composites of Fe0.5-NH3 and Mn-oxides were then investigated for ORR and HPRR. Improved selectivity during ORR was observed for all composites relative to Fe0.5-NH3 alone, but the effect was strongest for Mn2O3.Before investigating such catalysts in AEMFC, a study on the compatibility between different ORR and/or hydrogen oxidation reaction catalysts (Pt/C, Fe0.5-NH3, PtRu/C, Pd-CeO2/C) and anion exchange ionomers was performed in RDE in 0.1 M KOH. The study identified issues between the investigated ionomers and catalysts having low metal contents on the carbon support (Fe0.5-NH3, Pd-CeO2/C).The catalyst Fe0.5-NH3 and its composite with Mn2O3 were then investigated in AEMFC with an ethylene-tetrafluoroethylene ionomer. Both cathode catalysts reached a current density of ca 80 mA cm-2 at 0.9 V, with relatively low loading of 1.0-1.5 mg catalyst·cm-2. The peak power density with H2/O2 reached 1 W cm-2 at 60°C with a low density polyethylene AEM and 1.4 W cm-2 with high density polyethylene AEM at 65°C. By comparison, a current density of ca 70 mA cm-2 at 0.9 V and peak power density of 1.5 W cm-2 was reached with 0.45 mgPt cm-2 at the cathode (40 wt% Pt/C) with low density polyethylene AEM at 60°C. A durability test of 100 h at 0.6 A cm-2 in air showed good stability of the Fe0.5-NH3 catalyst.In conclusion, this work highlights the promising application of Fe-N-C catalysts at the cathode of AEMFCs for replacing precious metal catalysts.
Solid oxide fuel cells are promising renewable energy devices due to their high efficiency and fuel flexibility. As they operate at a higher temperature than other fuel cells, ceramic materials, such as perovskite-based La0.6Sr0.4CoO3 and La0.6Sr0.4Co0.2Fe0.8O3, can be used as electrodes to replace expensive noble metals. However, when the corresponding electrode and yttria-stabilized zirconia electrolyte are sintered together, SrZrO3 produced from a side reaction acts as an insulator and deteriorates the performance of the fuel cell. Thus, the dense functional layer of a ceria-based material should be introduced between the electrode and the electrolyte to suppress the formation of secondary phases. However, in the conventional cell manufacturing process, it is challenging to manufacture a dense functional layer under constrained sintering conditions. In this study, we develop a method for fabricating a dense gadolinia-doped ceria (GDC) functional layer, even under constrained sintering conditions, by using a sacrificial bismuth oxide, Bi2O3, sintering aid layer above the GDC layer. As thermal sintering progresses at 1000–1200 °C, the Bi2O3 sintering aid layer is sublimated, leaving only the pure GDC functional layer. The fabricated dense GDC functional layer characterized by various analysis methods shows improved solid oxide fuel cell performance.
For reliable operation, battery energy storage system (BESS) with renewable energy source (RES), such as a wind and solar‐based distribution system generally gives satisfactory performance when connected to AC grid. However, large charging time and requirement of one additional unit for recharging of batteries, and the intermittent nature of RESs are the main challenges associated with this system. These problems can be solved with non‐intermittent fuel cells that do not require recharging. There are various kinds of fuel cells and among them the solid oxide fuel cell (SOFC) is the most efficient on the distribution system. However, SOFC is a multiple‐input‐multiple‐output and non‐linear device. There exists a strong coupling between its control variables, and when it is connected to the AC grid, the control problem becomes severe, due to the addition of variables associated with inverter and its control circuitry. Therefore, firstly, the characteristics of SOFC have been studied, by linearising it in the MATLAB/SIMULINK environment. Finally, after selecting the appropriate control variable pairing, a systematic development of a coordinated control scheme has been accomplished for improving the life of SOFC by keeping its associated variables into the feasible operating limits. Comparison of simulation results shows the superior performance of proposed scheme in contrast to the already existing control scheme. With this proposed scheme, it is possible to keep the grid voltage and grid frequency at one per unit. Further, this chapter also highlights the worldwide recent trend of fuel cells with their techno‐economic aspects and market policies.
In light of recent alarming environmental trends combined with increasing commercial viability of fuel cells, the time is propitious for a book focusing on the systematic aspects of cell plant technology. This multidisciplinary text covers the main types of fuel cells, R&D issues, plant design and construction, and economic factors to provide industrial and academic researchers working in electrical systems design, electrochemistry, and engineering with a unique and comprehensive resource.
IntroductionAlkaline Fuel Cells (AFC) General PrincipleEarly Developments of Alkaline Fuel Cell SystemsFurther DevelopmentsPolymer-Electrolyte Fuel Cells (PEFCs) IntroductionHistory of DevelopmentOperating Principles of PEFCs GeneralElectrodesElectrolytes-MembranesHeat and Water ManagementPerformance of Polymer-Electrolyte Fuel Cells (PEFCs) Influence of TemperatureInfluence of Cathodic Reactant Composition and PressureInfluence of CO in the Fuel GasSolid-Polymer Fuel Cell StacksRegenerative Fuel Cell Systems General PrincipleEarly Developments of Alkaline Fuel Cell SystemsFurther Developments IntroductionHistory of DevelopmentOperating Principles of PEFCs GeneralElectrodesElectrolytes-MembranesHeat and Water ManagementPerformance of Polymer-Electrolyte Fuel Cells (PEFCs) Influence of TemperatureInfluence of Cathodic Reactant Composition and PressureInfluence of CO in the Fuel GasSolid-Polymer Fuel Cell StacksRegenerative Fuel Cell Systems GeneralElectrodesElectrolytes-MembranesHeat and Water Management Influence of TemperatureInfluence of Cathodic Reactant Composition and PressureInfluence of CO in the Fuel Gas
The recent progress of fuel cell development towards highly efficient and clean energy conversion allows increasing applications in the wide field of on-board electricity generation and alternative drive systems.Basic requirements and the status of proton exchange membrane (PEM) fuel cell development and its progress for hydrogen/air operation are analyzed. First car applications have demonstrated the high overall fuel efficiency and zero emission behavior of mobile fuel cell systems.However, the missing hydrogen infrastructure and the high volume necessary for hydrogen storage makes it desirable to have an on-board hydrogen conversion of liquid hydrocarbons available. Appropriate technical solutions in this field will have big markets in both mobile and stationary applications for decentralized power generation including a great impact on energy and environmental issues.
This unique book concerning fuel cells and their applications fills the gap which currently exists between the theoretical aspects and the detailed practical data available. It describes a technology that dates from the early classical discoveries of the 1850s which predicted that direct energy conversion of chemical energy into electricity with fuel cells would be far more efficient at lower temperatures than with combustion processes. The importance of fuel cells for energy saving purposes is emphasised. Their applications are wide-ranging with use found in local stations and power plants, in industry for the highly efficient conversion of waste and biomass materials and in carbon dioxide reduction in all fossil-fuel-burning processes. Unique features highlighted include their importance in spacecrafts and their development for affordable implementation in electric cars. The most recent scientific publications and manufacturer's brochures have been screened in order to bring together the state- of-the-art technology of fuel cells. Readers at all levels including chemists, physicists, chemical engineers ry technologists and students will appreciate this comprehensive overvie ind the clarity of numerous graphs and tables highly valuable. © VCH Verlagsgesellschaft mbH, D-69451 Weinheim, Federal Republic of Germany, 1996. All rights reserved.
The highly favorable efficiency/environmental characteristics of fuel cell technologies have now been verified by virtue of recent and ongoing field experience. The key issue regarding the timing and extent of fuel cell commercialization is the ability to reduce costs to acceptable levels in both stationary and transport applications. It is increasingly recognized that the fuel processing subsystem can have a major impact on overall system costs, particularly as ongoing R&D efforts result in reduction of the basic cost structure of stacks which currently dominate system costs. The fuel processing subsystem for polymer electrolyte membrane fuel cell (PEMFC) technology, which is the focus of transport applications, includes the reformer, shift reactors, and means for CO reduction. In addition to low cost, transport applications require a fuel processor that is compact and can start rapidly. This paper describes the impact of factors such as fuel choice, operating temperature, material selection, catalyst requirements, and controls on the cost of fuel processing systems. There are fuel processor technology paths which manufacturing cost analyses indicate are consistent with fuel processor subsystem costs of under $150/kW in stationary applications and $30/kW in transport applications. As such, the costs of mature fuel processing subsystem technologies should be consistent with their use in commercially viable fuel cell systems in both application categories.
World-wide a number of activities are concerned with the optimisation and development of cell materials and microstructures with the aim of reducing the solid oxide fuel cell (SOFC) operating temperature. Advantages for reduced operating temperatures are considered to be longer life time and reduced costs of the total system. Conventional zirconia based electrolyte cells with highly optimised electrodes have produced 500 mA/cm2 at 700 mV and 800°C. At a similar temperature and cell potential, small scale, co-fired, electrode supported thin-electrolyte cells have produced 700 mA/cm2. For SOFC operation at temperatures below 750°C the conventional 8 mol% Y2O3–ZrO2 electrolyte is replaced with either Ce0.9Gd0.1O1.95 (10GCO) or La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolytes. Up-scaled 10×10 cm2 or 12 cm circular 10GCO and LSGM cells have been manufactured and the initial results of cell tests are very promising.
Fuel-cell generating plants, which convert chemical energy
directly into electric energy, differ from conventional generating
plants by the absence of rotating machines. Such plants are expected to
see increasing practical use. Fuel-cell systems under development for
practical use are phosphoric acid (PAFC), molten carbonate (MCFC), solid
oxide, (SOFC), and proton exchange membrane (PEMFC). PAFC, which is the
closest of these systems to commercialization, has been developed
vigorously by the United States and Japan. The authors describe the
history of fuel-cell development, state of PAFC development, and key
inverter technologies
Fuel Cell Cogeneration-Technology Assessment Guide
- M W Ellis
M. W. Ellis, Fuel Cell Cogeneration-Technology Assessment
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Fuel cells start to look real
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S. Ashley, "Fuel cells start to look real," Automotive Eng. Int., Mar.
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Fuel Cell Cogeneration&mdash,Technology Assessment Guide
- M W Ellis
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