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S S Daud, M A Norrdin, J Jaafar et al.
IOP Conference Series: Materials Science and Engineering · 2019
Abstract Bipolar membrane fuel cell (BPMFC) was firstly discovered in 2000 that composed of two-layered ionic conducting membranes. The importance of BPMC development is its ability to humidify the cell when operating at a high current density that eliminates the use of the external humidification system. It is able to self-humidify the cell because of water formation at the intermediate layer from the reaction of hydrogen ion (H + ) with hydroxide ion (OH − ). Up to now, there is no commercial bipolar membrane (BPM) in water formation configuration for the fuel cell humidifying purpose. Thus, the researcher had come out with a composition of proton exchange membrane with anion exchange membrane by the hotpressing method that allows them to carry the proton and anion simultaneously in a single cell. There are a few of polymeric-based PEM and AEM material had been selected for developing BPM such as Nafion, FumaPEM FAA3, quaternary ammonium polysulfone (QAPSF), and quaternary ammonium poly(phenylene)oxide (QAPPO). This review aims to determine the effect of material selection and design for developing BPM toward its performance in fuel cell based on published works. Besides, the potentialities of polymeric-based material are discussed, pointing out the main positive and negative effect of this BPM for fuel cell applications. As a case study, the use of different types of PEM and AEM material for BPM is particularly stressed, pointing out the main properties for its applications in BPMFC.
Hong Ki Lee, Sung Wan Hong, Sung Won Yang et al.
Advanced Materials Research · 2007
For the regenerative fuel cell (RFC), water electrolysis cell performance using membrane electrode assembly (MEA) in polymer electrolyte fuel cell (PEMFC) were investigated. A part of Nafion had been secondary sprayed on the surface of catalytic layer and variation of cell performance was diminished. The conformation of stability, improvement of mechanical and electrical properties was accomplished by addition of PVDF, graphite and RuO2. With the addition of graphite power and RuO2, the voltage was decreased from 3.6V to 2.5V and 2.2V. The improvement of the mechanical properties was obtained by addition of PVDF. The electrolysis cell manufactured with MEA electrode was showed less decomposition voltage of 1.3V than with Nafion electrode at 10A of applied current. The stability of MEA was confirmed from 30 days of cell operation
Venko N. Beschkov, Elena N. Razkazova-Velkova, Martin S. Martinov et al.
Catalysts · 2021
Hydrogen sulfide is frequently met in natural waters, like mineral springs, but mostly it is found in marine water with low renewal rate. The Black Sea has extremely high hydrogen sulfide content. It can be utilized in different ways, but the most promising one is direct conversion into electricity. This result can be attained by a sulfide-driven fuel cell (SDFC), converting sulfide to sulfate thus releasing electric energy up to 24 GJ/t. One of the most important problems is the mass transfer limitation on oxygen transfer in the cathode space of the fuel cell. This problem can be solved using a gas diffusion electrode or highly efficient saturation by oxygen in an ejector of the Venturi tube type. This work presents experimental data in laboratory-scale SDFC for sulfide conversion into sulfate, sulfite and polysulfide releasing different amounts of electric energy. Two types of aeration are tested: direct air blow and Venturi-tube ejector. Besides pure graphite, two catalysts, i.e., cobalt spinel and zirconia-doped graphite were tested as anodes. Experiments were carried out at initial sulfide concentrations from 50 to 300 mg/L. Sulfate, sulfite and thiosulfate ions were detected in the outlet solutions from the fuel cell. The electrochemical results show good agreement with the chemical analyses. Most of the results show attained high efficiencies of the fuel cell, i.e., up to 80%. The practical applications of this method can be extended for other purposes, like treatment of polluted water together with utilization as energy.
P. Agrawal, S. Ebrahim, D. Ponnamma
International Journal of Energy and Water Resources · 2024
Abstract Fuel cells hold great promise as a clean energy technology, yet challenges such as material compatibility, manufacturing costs, and durability issues, particularly with noble metal-based electrocatalysts like platinum (Pt), hinder their widespread adoption. This review explores strategies to enhance fuel cell performance while minimizing costs, focusing on developing efficient and cost-effective catalysts supported by nanocarbon materials, such as carbon nanotubes, graphene, carbon films, and their composites. The investigation delves into how these catalysts supports improve activity and stability, leading to superior fuel cell performance characterized by higher current density and enhanced durability compared to conventional Pt/C catalysts, with a specific focus on proton-exchange membrane fuel cells. Key topics covered include the role of nanocarbon in fuel cells, various nanocarbon-based catalyst supports, Pt-containing alloys, non-Pt catalysts, and nanocarbon composites for electrolyte membranes and corrosion protection. Notable findings include the importance of heteroatom doping in enhancing reactivity, the effectiveness of organic–inorganic composite proton exchange membranes in improving proton conductivity, and the potential of amorphous carbon film coatings and conductive polymer-nanocarbon composites in enhancing corrosion resistance. These advancements underscore the potential of nanocarbon-based catalysts and coatings in ensuring the reliability and longevity of fuel cell components, thus contributing to the widespread commercialization of fuel cell technology.
Yewondwosen Gzate
Research Square · 2024
Abstract The aim of this work is to improve and compare the performance of pure gasoline ethanol blend and hydrous ethanol blend fuels for spark ignition engine without major fuel system component modification. The comparative experiments were conduct on mechanical gasoline engine fueled with pure gosine, E10 and HE10.The effects of the engine loads and the additions of ethanol and water on combustion and emission characteristics were analyzed deeply. The modified engine was tested with gasoline-ethanol-water blend emulsion as a fuel, and the effect of data were recorded on brake torque, brake power, brake specific fuel consumption, thermal efficiency, exhaust emission (CO, CO 2 , HC, O 2 ) and smoke emission. In addition to performance test, the study on the miscibility of water, ethanol and gasoline blend was conducted mainly to know what extent water can be added to ethanol gasoline blend without phase separation. The amount of water it can be tolerate in the hydrous alcohol when used as a blending component with gasoline is up to 5% of ethanol. Higher water solubility in ethanol gasoline blends may be obviously useful and suitable nevertheless, temperature continuous ability of water to remain soluble in the blend is significantly affected by temperature and improvement in combustion characteristics. According to the experimental results, compared with pure gasoline and E10 blend, HE10 showed higher peak brake torque at high load. Increases in brake power were observes for HE10 fuel at all the operating conditions. The usage of HE10 fuel at optimum load conditions reduces HC, CO and CO 2 emissions significantly. In addition, decreases in NO X emissions were observed for HE10 from 0 Nm to 80 Nm. From the results, it can be concluded that HE10 fuel can be regard as a potential alternative fuel for gasoline engine applications.
Syarifah Noor Syakiylla Sayed Daud, Muhamad Noorul Anam Mohd Norddin, Juhana Jaafar et al.
Journal of Applied Membrane Science & Technology · 2022
The membrane in a fuel cell plays an essential role in permeating the ionic charges of positive and negative ions without passing the fuels and electrons through it. The membrane's common materials are perfluorinated polymer, non-fluorinated or hydrocarbon polymer, and natural polymer. The physicochemical properties of the membrane have the most significant influence on the performance of fuel cells in terms of mechanical stability, ionic conductivity, power output, and cell operation longevity. The incorporation of nanoparticles into polymeric-based materials improved the membrane's properties by suppressing fuel crossover, improving water retention, and increasing ionic mobility across the membrane. The effect of incorporating nanoparticles is determined by their type, size, shape, surface acidity, and relationship to the polymer matrix. The blending, sol-gel, and infiltration methods are used to develop the nanocomposite membrane. Compared to a commercial membrane in a fuel cell application, most of these membranes demonstrated superior cell performance. Based on published literature, this review briefly described the design and influence of specific advanced nanomaterials incorporated in polymer matrix toward membrane performance.
Chen Li, Xiaoming Xu, Hao Hu et al.
Journal of Electrochemical Energy Conversion and Storage · 2021
Abstract The electrochemical reaction inside a high-power fuel cell generates a lot of heat. Excessive heat affects the performance of the membrane, so it is necessary to introduce coolant. The main objective of coolant is regulating the temperature of relatively high-power proton exchange membrane fuel cell (PEMFC) stacks efficiently. The coolant channel has a great influence on the performance of PEMFC. In this work, a multiphase, 3D PEMFC model with serpentine flow channel is developed. In order to rank structural parameters according to the degree of influence on fuel cell performance, this study analyzed the current density, O2 mass fraction, and the distributions of temperature based on an orthogonal test scheme with three factors and three levels. The results show that rib width between the reactant flow channel and the cooling channel has the greatest influence on the current density, and gas flow channel width has the least influence.
F. A. de Bruijn, V. A. T. Dam, G. J. M. Janssen
Fuel Cells · 2008
Abstract Besides cost reduction, durability is the most important issue to be solved before commercialisation of PEM Fuel Cells can be successful. For a fuel cell operating under constant load conditions, at a relative humidity close to 100% and at a temperature of maximum 75 °C, using optimal stack and flow design, the voltage degradation can be as low as 1–2 μV·h. However, the degradation rates can increase by orders of magnitude when conditions include some of the following, i.e. load cycling, start–stop cycles, low humidification or humidification cycling, temperatures of 90 °C or higher and fuel starvation. This review paper aims at assessing the degradation mechanisms of membranes, electrodes, bipolar plates and seals. By collecting long‐term experiments as well, the relative importance of these degradation mechanisms and the operating conditions become apparent.
I G Bratu, R F Ene, M Vulpe et al.
IOP Conference Series: Earth and Environmental Science · 2021
Abstract The performance of PEM fuel cells is influenced by several factors such as: the operating temperature of the cell, the reactant gas flow, work pressures, the reaction gas humidity. In the present work we aimed to identify the optimal values of these parameters for operation of a PEM cell to achieve maximum power in conditions of high efficiency; the technological possibilities of its use in a portable energy application have been evaluated. Experimental measurements regarding the integrating polymeric membrane in three different fuel cell construction designed were performed. The influence of the mechanical compression of the GDL diffusion layer on the total internal resistance of the cell was achieved by comparative analysis of the polarization curves. It was found that as the deformation level of the MEA increases, the power generated by the battery increases progressively. The resulting experimental data subsequently allowed the design and implementation of a PEM fuel cell assembly, fully functional at power level, corresponding to the number of constituent elements.
Elif Eker Kahveci, Imdat Taymaz
E3S Web of Conferences · 2019
In this study, the effects of operating parameters on power density of a 3-cell PEMFC (Polymer Electrolyte Membrane Fuel Cell) stack with serpentine flow channels having 150 cm 2 total active layer have been examined experimentally. Desing Expert, which is the experimental design program (trial version) was used, and the data obtained as a result of the experiments were analyzed by entering this program. A total of 25 experiments were carried out according to the design created with the data entered into the program within the specified operating conditions range. The independent variables were entered which are cell temperature, humidification temperature, H 2 flow rate and O 2 flow rate, and the response is the power density. In this study, the hydrophobic cell stack which has the highest cell performance of which was previous studies results was used. In the optimization study, keeping the power density and maximum H 2 flow to a minimum, the most suitable values are cell temperature 57.826°C, humidification temperature 56.151°C, O 2 flow 1.587 L/min. Finally 432.398 mW/cm 2 power density value was obtained under these operating conditions.
Stuart Holmes, Maria Perez Page, Madhumita Sahoo et al.
ECS Meeting Abstracts · 2018
Fuel Cells have attracted great attention in recent times since can offer numerous benefits such a high power density, compactness, lightweight and zero emissions. One of the most attractive and effective regarding transportation applications is low temperature fuel cell or Proton Exchange Membrane Fuel Cells (PEMFC). Great efforts have been made to research of different materials to improve this Fuel Cell performance. Graphene materials have been attracted great interest in their electrical and barrier properties. CVD Graphene monolayer is an excellent electronic conductor in-plane and impermeable to all species except the protons through the plane. Graphene oxide has been demonstrated to be an ionic conductor but impermeable to dry gases and electrons. Graphene oxide is an organophobic material, property which makes this material as a good barrier. Different studies have been carried out for The University of Manchester to prove that incorporate CVD Graphene, Reduced Graphene Oxide (rGO) and Graphene oxide (GO) into the different layer of the PEM fuel cell Membrane Electrode Assemblies (MEAs) [1,2]. GO has been added as a barrier layer in Direct Methanol Fuel Cells providing additional tortuosity and decreasing the methanol crossover, one of the most important inconvenient in this type of PEM fuel cells. rGO has been incorporated as a catalyst support obtaining an important improvement in the methanol oxidation reaction. Several graphene preparation methods have been developed, such as chemical vapour deposition (CVD), arc discharge, segregation growth or Hummers method. However, the requirements of expensive equipment used, extreme reaction conditions and the usage of highly toxic chemicals are some of the inconvenient that these techniques present. Then, the synthesis of graphene in both high quality and quantity via economic ways is one of the most important challenges nowadays for practical applications. Electrochemical exfoliation of graphite has been presented as a green and cost-effective approach for producing high quality of graphene in high yield using simple equipment [3-5]. This work presents an alternative to Hummer’s method to produce GO and rGO by Electrochemical Exfoliation of Graphite. A simple two electrodes configuration, counter electrode and working electrode in different electrolyte solutions, NH 4 NO 3 , (NH 4 ) 2 SO 4 , has been carried out to produce this GO. Figure1 shows preliminary characterization results of GO produced by electrochemical exfoliation (EGO) using NH 4 NO 3 as electrolyte. Single flakes of GO can be observed in the TEM image. Raman spectra and their I D /I G ratio show that EGO presents a good quality compared with Hummer’s method. GO produced by Electrochemical Exfoliation will be incorporated into different MEAs layer to obtain an enhanced performance of low temperature fuel cell. GO. Effect of GO on the fuel cell was studied by electrochemical characterization. References: [1] Stuart M. Holmes, Orabhuraj Balakrishnan, Vasu. S. Kalangi, Xiang Zhang, Marcelo Lozada-Hidalgo, Pulickel M Ajayan, Rahul R. Nair. 2D Crystals Significantly Enhance the Performance of a Working Fuel Cell. Advance Energy Materials , 7, (2017). [2] S. Al-Batty, C. Dawson, S. P. Shanmukham, E. P. L. Roberts and S. M. Holmes. Improvement of direct methanol fuel cell performance using a novel mordenite barrier layer . J Mater. Chem . A, 2016, 4, pp. 10850-10857. [3] Richard Gondosiswanto, Xunyu Lu, and Chuan Zhao. Preparation of Metal-Free Nitrogen-Doped Graphene via direct electrochemical exfoliation of graphite in ammonium nitrate. Australian Journal of Chemistry , 68 (2015) 830-835. [4] Xunyu Lu and Zhao. Controlled electrochemical intercalation, exfoliation and in-situ nitrogen doping of graphite in nitrate-based proton ionic liquids . Physical Chemistry Chemical Physics, 15 (2013), 30005-200009. [5] Khaled Parvez, Ahong-shuai Wu, Tongjin Li, Xianjie Liu, Robert Graft, Xinliang Feng, and Klaus Mullen. Exfoliation of Graphite into Graphene in Aqueous solution of Inorganic Salts. Journal of the American Chemical Society, 136, (2014), 6038-6091. Figure 1
Vinaykumar Konduru, Ezequiel Medici, Jeffrey S. Allen
ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology · 2013
Water transport in the Porous Transport Layer (PTL) plays an important role in the efficient operation of polymer electrolyte membrane fuel cells (PEMFC). Excessive water content as well as dry operating conditions are unfavorable for efficient and reliable operation of the fuel cell. The effect of thermal conductivity and porosity on water management are investigated by simulating two-phase flow in the PTL of the fuel cell using a network model. In the model, the PTL consists of a pore-phase and a solid-phase. Different models of the PTLs are generated using independent Weibull distributions for the pore-phase and the solid-phase. The specific arrangement of the pores and solid elements is varied to obtain different PTL realizations for the same Weibull parameters. The properties of PTL are varied by changing the porosity and thermal conductivity. The parameters affecting operating conditions include the temperature, relative humidity in the flow channel and voltage and current density. A parametric study of different solid-phase distributions of the PTL and its effect on thermal, vapor and liquid transport in the PTL under different operating conditions are discussed.
Zachary R. Williamson, Daejoong Kim, Dae-Keun Chun et al.
ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology · 2010
An experimental analysis of cell temperature effects on an air-breathing, PEM fuel cell is presented. The cell was tested in three active area sizes of 5 cm2, 10 cm2, and 25 cm2. The cell’s design minimized the influence of self-heating by using a large thermal body in its construction which conducted heat away from the active area. This allowed for the use of a heater and controller to test a constant cell temperature uninfluenced by current density. Polarization and electrochemical impedance spectroscopy testing showed that at higher current density, elevated temperature increased the buoyancy of the air around the cell which improved open cell performance. However, the opposite is true for lower current density as membrane dehydration becomes more prevalent at higher temperatures. Schlieren imaging, in conjunction with the polarization and EIS data, shows how heated and more buoyant air boosts cell performance. Infrared imaging identifies temperature gradients on the active surface which may hinder cell performance slightly.
Yavuz Yagizatli, Irfan Ar
Journal of Polymers and the Environment · 2024
Abstract This study focuses on developing an alternative membrane for PEMFC due to the disadvantages of using Nafion. Fluoroboric acid (FBA) was used as an additive material to SPEEK-PVA blend membranes at different weight ratios (1%, 5%, 7.5%, 10%, and 12.5%), and a synthesis procedure was carried out with the solution-casting. Thermal crosslinking was performed with all membranes. Utilizing FBA, with its highly electronegative fluorine groups, is a novel approach expected to enhance proton conductivity. The structural, morphological, and thermal properties of the synthesized membranes were determined by FTIR, XRD, SEM, TGA-DTG, and DSC. Water uptake capacity (WUC), swelling property, area change, dynamic mechanical analysis, ion exchange capacity (IEC), AC impedance analysis, hydrolytic stability, and oxidative stability analyses were performed for fuel cell applications. Although FBA does not have a crystal structure, the synergy it created with the SPEEK-PVA membrane increased the crystallinity of the membrane and, accordingly, glass transition temperature. SEM images of membranes at a ratio above 7.5% show that agglomerations occur in the structure and this is supported by other analyses. It was determined that the membrane composition with the highest WUC (16.44%), IEC (1.55 meq/g), and proton conductivity (0.57 S/cm) values contained 7.5% FBA from the characterization studies, and a single-cell performance test was actualized with this. 418 mA/cm 2 current density and 250.8 mW/cm 2 power density were obtained at 0.6 V cell potential, with the membrane containing 7.5% FBA. This study shows that the synthesized membrane, especially the FBA, is a promising option for PEMFC application. Graphical Abstract
K. Krishna Pandi, K. Ramesh, D. Kulandaivel et al.
international journal of engineering technology and management sciences · 2022
Over the past ten years, proton exchange membrane (PEM) fuel cells have gained popularity as a potential energy source. PEM fuel cells are a high efficiency, environmentally friendly power source that are not constrained by Carnot efficiency. Due to its characteristics of zero emissions, high power density, rapid start-up, and low operating temperature, they are seen as one of the attractive options to be utilized for electric cars. In this project work, a fuel cell uses that a low cost bipolar plate material with a high fuel cell performance are important for the establishment of PEM fuel cells into the competitive market world are taken in consideration. The analysis is carried out for the selected materials like Aluminium, Copper and Stainless steel on considering the design and operational parametric conditions of the PEM fuel cell. The aluminium bipolar plate exhibits improved uniformity in the dispersion of hydrogen, oxygen, and water vapour, which will improve the ionic conductivity in the membrane. After analysing the data, we found that the aluminium bipolar plate material had the best temperature distribution in the fuel cell and the lowest pressure loss when compared to the copper and stainless steel materials. Therefore, due to its light weight and reasonably low price of material, aluminium serpentine bipolar plate material may be thought of as the ideal bipolar plate material, especially for portable applications.
Jalal Tavalaei, Zulkurnain Abdul-Malek, Amir Hesam Khavari et al.
Applied Mechanics and Materials · 2015
Non linear resonance usually resonates in network which is consisting of ferromagneticcore. When distributed capacitance calculated form circuit breaker; mainly circuit breaker and cablecapacitance; after switching and opening the network feed apparatus, magnetization current on ferromagnetic core jump to saturation. Duration of ferroresonance is deeply relying on capacitance, and itwill be decaying by disembarking total store energy. Although, ferroresonance commence by switching circuit breaker off; protecting relay and other protecting schemes have no reaction, because thelast protection step for saving a device is a circuit breaker. There is no reported method to mitigatedisruptive phenomenon; which elder publication focus on the explosion of capacitive transformer,melting of power transformer core lamination and arresters problem. This work is tried to dampingferroresonance and reducing devastation effect on the apparatus. While, protecting devices is useless,fault point topology mutating by FACTS to control and decrease this phenomenon. FACTS deviceis settled at the upstream of apparatus to improve power quality, is switched on at initiating momentresonating. Modeling and simulating of ferroresonance are done by the actual value of transformerand other power system related devices extracted by UTM-TNB.
Konstantin A. Weber, Marta Zaton, Mark Muggli et al.
ECS Meeting Abstracts · 2023
Within the past years, proton exchange membrane (PEM) fuel cells have become more and more attractive due to their potential for the transition towards an environmentally friendly hydrogen economy. Especially by reducing the platinum catalyst loading, significant system cost reductions could be achieved, but low Pt loadings still lead to unassigned voltage losses during operation. [1,2] In order to overcome those losses, well-designed catalyst layers with optimized ionomer content and distribution are indispensable. The used perfluorosulfonic acid (PFSA) ionomers for PEM fuel cells are commonly characterized by the chemical structure of the ionomer and the equivalent weight (EW), which strongly affects the proton conductivity. [3,4] Current research focusses on the synthesis of modified ionomers with higher oxygen permeability to reduce mass transport losses, but also investigates the influence of the ionomer’s molecular weight (MW). [1,5,6] A high MW minimizes the water uptake of the ionomer/membrane in liquid water, which is desired for the use in PEM fuel cells to reduce mechanical stress during relative humidity (RH) cycling. [5] The exact MW of an ionomer is not easily accessible, but can be estimated by measuring the melt flow index (MFI), whereas a high MW is commonly reflected by a lower MFI if the ionomer chemistry and EW are the same. Within this study, a 3M ionomer modified to have a high MFI of 156 g/10 min (measured at 265 °C with a mass of 5 kg) is investigated and compared to a 3M standard ionomer with a low MFI of 6 g/10 min. Both PFSA ionomers have the same chemical structure and a similar EW of ~800. The significantly higher MFI of the modified ionomer (i.e., comprising a lower MW) is clearly reflected by a ~2 times higher water uptake compared to the 3M standard ionomer (measured for solution-cast membranes in liquid water at 80 °C). To evaluate the impact of the MFI within the cathode electrode, 5 cm² active area membrane electrode assemblies (MEAs) with these two ionomers at various ionomer/carbon (I/C) mass ratios in the cathode electrode (based on a 40 wt.% Pt/Vulcan catalyst at loadings of 0.11 mg Pt /cm²) are manufactured and electrochemically characterized. At sufficiently high I/C ratios and under humid operation (i.e., I/C = 0.90 and 90 % RH), differential flow H 2 /air polarization curves of the MEAs reveal that the higher liquid water uptake of the 3M high-MFI ionomer can be correlated with a lower cell voltage (see Figure 1). Contrary to the MEAs with the 3M low-MFI standard ionomer, the larger ionomer swelling in MEAs with the 3M high-MFI ionomer reduces the void volume fraction in the electrode structure during operation. Most pronounced at high current densities, where oxygen mass transport plays an important role, the MEAs containing the 3M high-MFI ionomer show a significant voltage loss of ~50 mV at 2.5 A/cm² compared to the MEAs with the 3M low-MFI ionomer. This study demonstrates that the effect of ionomer volume expansion upon changes in the MFI and thus the MW might not be crucial for the MEA performance when using electrodes with a low I/C ratio, but is critical when aiming for electrode compositions with a high ionomer content, in which case a low-MFI (i.e., a high MW) ionomer should be favorable. References [1] A. Kongkanand and M. F. Mathias, J. Phys. Chem. Lett., 7 (7), 1127–1137 (2016). [2] A. Z. Weber and A. Kusoglu, J. Mater. Chem. A, 2 (41), 17207–17211 (2014). [3] M. Doyle and G. Rajendran. in Handbook of Fuel Cells: Fundamentals, Technology, Applications , W. Vielstich, A. Lamm, H. A. Gasteiger, Editor, p. 538, Chichester, John Wiley & Sons Ltd. (2003). [4] N. Ramaswamy, S. Kumaraguru, R. Koestner, T. Fuller, W. Gu, N. Kariuki, D. Myers, P. J. Dudenas and A. Kusoglu, J. Electrochem. Soc., 168 (2), 24518 (2021). [5] Y. Li, R. Jiang and C. Gittleman, J. Power Sources, 478, 228734 (2020). [6] A. Katzenberg, A. Chowdhury, M. Fang, A. Z. Weber, Y. Okamoto, A. Kusoglu and M. A. Modestino, J. Am. Chem. Soc., 142 (8), 3742–3752 (2020). Acknowledgements This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under grant agreement No 826097. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation program, Hydrogen Europe and Hydrogen Europe Research. Figure 1
John F. Cooper
2nd International Conference on Fuel Cell Science, Engineering and Technology · 2003
A direct carbon fuel cell (DCFC) using a carbon-rich derivative of coal would maximize the conversion efficiency of this vast energy resource by avoiding the efficiency limitations of heat engines. A total conversion efficiency of 80% (based on heat of combustion of carbon) has been achieved at 30–120 mA/cm2 using carbon materials extracted from coal and other fossil resources. High experimental efficiency is grounded in two favorable aspects of the reaction thermodynamics. The net fuel cell reaction (C + O2 = CO2) has a nearly zero entropy change and therefore a theoretical efficiency of 100%. The fixed chemical potentials of carbon reactant and CO2 product make possible the full utilization of fuel in a single pass through the cell. The pure CO2 product can be used directly in enhanced oil and gas recovery, or sequestered. Historically, the development of carbon fuel cells have been limited by low anode rates, accumulation of impurities in the electrolyte, logistics of refueling, and lack of suitable cathodes. These problems are being addressed by recent developments of highly reactive carbon materials, low-cost techniques for separation of coal from ash, the possibility of pneumatic distribution of solid particulate fuel to the cells, and availability of cathodes from the molten carbonate fuel cell technology. Rate depends on atomic scale disorder and accessibility of reactive sites, but not on purity. Sources of suitable anode fuel include thermally decomposed products of (1) mechanical and chemical coal/ash separation or (2) solvent extraction. With current understanding of the cell basics, the next steps are demonstration of an engineering scale fuel cell stack (∼1 kW), supported by development of coal-to-carbon processes and techniques of electrolyte management. Successful development of a direct conversion fuel cell for coal (or coal-derived carbon) has extraordinary implications in extending the energy reserves of coal-producing nations, easing the control of regulated emissions at the plant, and expanding the use the earth’s greatest fossil resource while decreasing emissions of greenhouse gas.
Liping Fan, Yaobin Xi
Energies · 2021
Anode modification is a useful method to increase the performance of microbial fuel cells (MFCs). By using the electrochemical deposition method, Fe3O4 and polypyrrole (PPy) were polymerized on a carbon felt anode to prepare Fe3O4-PPy composite modified anodes. In order to ascertain the effect of electrodeposition time on characteristics of the modified electrode, the preparation time of the modified electrode was adjusted. The modified anodes were used in MFCs, and their performances were evaluated by analyzing the electricity generation performance and sewage treatment capacity of MFCs. Experimental results indicated that the Fe3O4-PPy composite modified anodes could enhance the power production capacity and sewage treatment efficiency of MFC effectively. In particular, when the deposition time was 50 min, the modified anode could significantly improve the MFC performance. In this case, the steady-state current density of MFC increased by 59.5% in comparison with that of the MFC with an unmodified carbon felt anode, and the chemical oxygen demand (COD) removal rate was 95.3% higher than that of the unmodified anode. Therefore, the Fe3O4-PPy composite is an effective material for electrode modification, and a good anode modification effect can be obtained by selecting the appropriate electrodeposition time.
Linda Ney, Jean-Luc Wolken, Rajveer Singh et al.
ECS Meeting Abstracts · 2022
The manufacturing process of catalyst coated membranes for polymer electrolyte fuel cells (PEMFC) needs to be transferred to high throughput mass production to meet the increasing demand on the market. After the coating of the catalyst ink, the drying temperature and its profile can change the pore structure and crack appearance of the catalyst layer by influencing the solvent evaporation [1]. Therefore, adjusting the drying parameters to the type of solvents within the catalyst ink can result in beneficial performance gain. Often solvents with low boiling points like isopropanol-water mixtures are used. The rapid evaporation of these solvents could lead to crack formation, which could be avoided by the usage of high boiling point solvents like e.g. ethylene glycol [2,3]. Therefore higher drying temperatures are necessary to ensure a complete removal of the wet components. This leads to the question of the maximum drying temperature which can be applied to speed up the drying process as much as possible. The most temperature sensitive component within the catalyst layer is the ionomer. Drying at high temperatures could lead to degradation and decomposition of the ionomer network within the catalyst layer. However, is the temperature too low, the necessary drying time increases, which would result in higher investment costs for longer drying process lines. Within this study we investigated at first the thermal behavior of short side chain (Aquivion®) and long side chain (Nafion™) ionomer dispersions to analyze their glass transition and melting temperatures with differential scanning calorimetry in the range of 30-400°C. The findings are shown in Figure 1. The glass transition temperature of Aquivion® lies between 154-159°C, whereas Nafion™ is more temperature sensitive with 125-142°C, which is consistent with the literature. In a second step, catalyst layers have been fabricated by screen printing with a catalyst paste including a solvent mixture of ethylene glycol and 1-methoxy-2-propanol [4]. The resulting catalyst layers have platinum loadings of 0.154 mg/cm² on the cathode and 0.05 mg/cm² on the anode side. The drying temperature has been varied between 22°C (ambient air temperature), 110°C, 150°C, 180°C, 200°C and 250°C within a continuous convection dryer. Further, different drying profiles have been applied by comparing to hot plate drying method. All other process parameters have been kept constant. The catalyst layers with different drying temperatures have been tested in-situ by electrochemical operation of the MEA. For Aquivion® as ionomer, the polarization curves are shown in Figure 2 and indicate that drying temperatures above 150°C (glass transition temperature) would lead to significant current density losses at wet and dry conditions. Furthermore, there doesn’t seem to be an optimum drying temperature below the glass transition temperature. Therefore, the best compromise of production throughput and electrochemical performance is reached at a temperature of 150°C, which is near the glass transition temperature of the ionomer. [1] Park H-S, Cho Y-H, Cho Y-H, Jung CR, Jang JH, Sung Y-E. Performance enhancement of PEMFC through temperature control in catalyst layer fabrication. Electrochimica Acta 2007;53(2):763–7. [2] Huang D-C, Yu P-J, Liu F-J, Huang S-L, Hsueh K-L, Chen Y-C et al. Effect of Dispersion Solvent in Catalyst Ink on Proton Exchange Membrane Fuel Cell Performance. Int. J. Electrochem. Sci. International Journal 2011;6:2551–65. [3] Hasegawa N, Kamiya A, Matsunaga T, Kitano N, Harada M. Analysis of crack formation during fuel cell catalyst ink drying process. Reduction of catalyst layer cracking by addition of high boiling point solvent. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2021:127153. [4] Alink R, Singh R, Schneider P, Christmann K, Schall J, Keding R et al. Full Parametric Study of the Influence of Ionomer Content, Catalyst Loading and Catalyst Type on Oxygen and Ion Transport in PEM Fuel Cell Catalyst Layers. Molecules (Basel, Switzerland) 2020;25(7). Figure 1
Nur Fawwaz Asri, Teuku Husaini, Abu Bakar Sulong et al.
Jurnal Kejuruteraan · 2020
Metallic bipolar plates tendency to have high contact resistance and corrosion after several times of usage affected performance of a cell in PEMFC stack. This study focused on the interfacial contact resistance (ICR) and corrosion resistance of SUS 316 L bipolar plates using Cr‒C and Nb‒C as coating layer, single stack performance in PEMFC were observed by experimental. The Cr‒C and Nb‒C coating layer acted as protective layer between SUS 316 L bipolar plates. Therefore, coating is a method in preventing the bipolar plates surface material from damage in the acidic environment of PEMFC. To develop corrosion-resistant and high conductivity bipolar plates for PEMFC, the coatings bipolar plates were applied to cell fabrication in comparison with bare SUS 316 L bipolar plates. The SUS 316 L bipolar plates size and electrode area were 50 mm2 and 25 mm2, respectively. The experiment was carried out on a prepared assembled single cell bipolar plates with the commercial membranes, conductive carbon papers and gasket. Initial performance of the single cells using Cr‒C and Nb‒C coatings over SUS 316 L bipolar plates were recorded at a cell voltage between 0.4 to 0.5 V, respectively. In comparison, Nb‒C gives good performance of corrosion resistance and the ICR value as low as 10‒12 A/cm2 and 1.22 mΩ cm−2. Additionally, it gives maximum power density of 137 mW/cm2 at the cell voltage 0.51 V. The lifetime durability of the single cell significantly improved from the uncoated current density of 390 mA/cm2 to 450 mA/cm2 with Nb‒C coating layer.
Jingying Ma, Zhihao An, Wenwen Zhang et al.
Analytical Science Advances · 2022
Abstract Optimization of dye decolourization for wastewater and power production are explored in dual‐chamber microbial fuel cells (MFCs) with TiO 2 /CdS photocathodes. The rapid reduction of azo dye methylene blue (MB) and power production were enhanced with TiO 2 /CdS photocathode under illumination. The analysis of electrochemical impedance spectra indicated that the photocatalysis of TiO 2 /CdS accelerated the electron transfer process of photoelectrode reduction. Moreover, the UV‐visible light spectrophotometer showed that the maximum degradation of the MFCs was 98.25%, which illustrated that MB may be cleaved by photoelectrons generated by light irradiation on the illuminated TiO 2 /CdS photocathode. Finally, the power production of MFCs in this work promoted reductive decolourization of the dye MB solution.
Xiaojun Zhao, Xuesong Shen, Yanbo Wang et al.
SAE Technical Paper Series · 2025
<div class="section abstract"><div class="htmlview paragraph">The dynamic behavior of the water and thermal management are critical to stabilize the performance of the proton exchange membrane fuel cell (PEMFC) during severe load changes. In this paper, a fuel cell hybrid electric vehicle (FCHEV) dynamic simulation model is established to evaluate the changes in liquid water and temperature distribution inside the fuel cell stack under a vehicle driving cycle conditions. This paper focuses on analyzing the power generation performance of the stack and the dynamic behavior of internal water and heat transfer following the demand of the vehicle. According to the simulation results, the temperature of MEA and cooling water fluctuates greatly, but the temperature of MEA is always higher than the cooling water temperature by about 1.57 degrees Celsius (average value). Compared to the experimental measurements of temperature, the simulation error for the maximum temperature is 3.4% and the simulation error for the average temperature is 4.4%. The accuracy of the simulation model is less than 5%. Based on the temperature distribution, a fuel cell system temperature control method is proposed, which is helpful to the optimization of the system and control design for the PEMFC system in FCHEV.</div></div>
Rod L. Borup, Adam Z Weber, Deborah J Myers et al.
ECS Meeting Abstracts · 2017
The FC-PAD (Fuel Cell – Performance and Durability) consortium coordinates national laboratory activities related to fuel cell performance and durability, provides technical expertise, and integrate activities with industrial developers. The national laboratory core teams have the responsibility to carry out foundational research and capabilities development, and provide support for the individual projects’ research efforts. This consortium incorporates National-Laboratory investigators related to durability, transport, and performance, and combines them into one highly coordinated effort. The consortium formalized already existing and effective collaborations amongst the National Laboratories that established leadership in PEMFC performance and durability research and development. The consortium coordinates work under in different Thrust Areas including component thrust areas and cross-cutting thrust areas. The six different thrust areas are: Component Thrust Areas: Electrocatalysts and Supports Electrode Layers Ionomers, Gas Diffusion Layers, Bipolar Plates, Interfaces Cross-cutting Thrust Areas: Modeling and Validation Operando Evaluation: Benchmarking, ASTs, and Contaminants Component Characterization and Diagnostics The structure of FC-PAD utilizes multiple cross-cutting thrust areas from theoretical modeling to characterization including benchmarking new materials that are provided to FC-PAD. The FC-PAD structure brings together world-class scientists into one integrated consortium, yet it provides a flexible structure to strategically use the widely varying expertise. The FC-PAD consortium is examining degradation mechanisms to help develop improved materials and operating strategies. Corrosion of the carbon electrocatalyst support has been measured during drive-cycle operating conditions and increases with increase potential cycling from 0.4 to 0.9 V. Carbon corrosion is one of the major contributors to degradation which leads to changes in the catalyst layer structure and reduces its activity. Reduction in catalyst layer thickness is observed during operation, exacerbated during drive cycles. This reduction can be due to the loss of carbon through carbon corrosion or due to compaction; both effects likely lead to a loss of void volume. Membrane additives which increase membrane life-times, have been measured to migrate into the catalyst layer and appear to be associated with the carbon in the catalyst layers. Low potentials (0.2V) appear to be required to remove membrane fragment adsorbates which decrease catalyst activity. Pt alloy catalysts lose most of their alloying agents during operation; the alloying agents migrated throughout the ionomer. Durability implications of using Pt-X alloy catalysts will be discussed. Results related to the mentioned degradation mechanisms will be presented including characterization from TEM, SEM, XRF, XRD and electrochemical testing. Consortium members include Argonne National Laboratory, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, the National Renewable Energy Laboratory and Oak Ridge National Laboratory. Acknowledgments This work was funded through the DOE FC-PAD Consortium with thanks to DOE EERE FCTO, Fuel Cell Team Leader: Dimitrios Papageoropoulos
Debajyoti Bose, Mahula Santra, Rama Venkata Siva Prasanna Sanka et al.
International Journal of Energy Research · 2020
Summary In natural environments, voltage gradients can be created in soil or sediments from inherent microbial activity. Present work has utilized sediment microbial fuel cell or s‐MFC for dark flocculent surface sediments to see bioelectricity generation potential at Jaipur, Rajasthan in India. Using a glucose rich substrate media and low external resistance, system generated external voltage of around 500 ± 10 mV, with power density peaking after a week of operation with 2122 ± 80 mW/m 2 and current density of 4.31 mA/m 2 ; s‐MFC reactor components included six graphite based anodes, placed strategically in the sediments, connected in series to a cathode for enhanced system performance. FTIR analysis of the surface sediment showed the presence of complex organic and inorganic compounds that allow stable biofilm formation, which influences power density directly. Such systems provide a novel route to bioremediation using microbial metabolism and can provide remote power generation for oceanographic instruments, biosensors and similar low power devices.
J. I. San Martín, I. Zamora, V. Aperribay et al.
Fuel Cells · 2014
Abstract One of the most outstanding products of fuel cells is electrical power but, currently, there is a reduced number of publications that provide experimental data about the performance of fuel cells when used for supplying Alternating Current (AC) loads. Most of the existing publications provide experimental data only with direct current (DC) loads, or analyze the performance with AC loads using simulation models. For this reason, this paper analyses experimentally the behavior of a proton exchange membrane fuel cell (PEMFC) system when feeding different electrical loads. The system tested is constituted by a PEM fuel cell, a storage battery, electronic converters and electrical loads. In the tests, the fuel cell system supplies power to three different loads: DC, single‐phase AC and three‐phase AC. For these cases, voltage, current, power, power factor and efficiency data are shown, at different load levels. From those parameters, efficiency of the global system is estimated. Finally, as the power quality concept is a topic of increasing importance when supplying electricity, the total harmonic distortion (THD) of the electric signals has also been analyzed.
Xiaohua Zhao, Tian Tian, Min Guo et al.
Journal of Chemical Technology & Biotechnology · 2019
Abstract BACKGROUND The morphology and size of MnO 2 that deposited on a carbon clothelectrode have dramatic effects on the electrochemical properties and cycling life. Currently, MnO 2 and its composite structures with zero‐dimensional (0D) nanospheres, one‐dimension (1D) nanotubes and two‐dimension (2D) nanomesh have been successfully synthesized and employed in MFC. Hence, the development of a three‐dimensional (3D) flexible, cost‐effective and high‐performance anode is of great significance for microbial energy harvesting. RESULT Herein, we have fabricated 3D cauliflower‐like polypyrrole@manganese dioxide (PPy@MnO 2 ) composites, which are successfully grown on carbon cloth (CC) anode by electrodeposition to promote the power production and storage in microbial fuel cells (MFCs). Impressively, the as‐prepared PPy@MnO 2 modified CC anode delivers a power density of 2139.7 ± 17.5 mW m −2 and produces an areal capacitance of 1120 ± 12.8 mF cm −2 , which is 3.58 and 4.84 folds higher than that with bare CC anode, benefiting from the unique cauliflower‐like 3D architecture with increased active centers that host the bacteria for more efficient charge transfer. Electrochemical analyses indicate that the PPy@MnO 2 modified CC electrode has excellent electrochemical activity, capacitive behavior and long‐term cyclabilities with smooth surface morphology and high porosity. CONCLUSION These findings not only provide a facile electrodeposition strategy for PPy@MnO 2 nanoflowers modified CC anode, but also demonstrates its potential for the production and storage of energy simultaneously in MFC application. © 2019 Society of Chemical Industry
Rhushikesh Ghotkar, Ryan J. Milcarek
ASME 2020 Power Conference · 2020
Abstract Direct flame fuel cells were developed in 2004 and there have been many iterations of them ever since. One of the latest iterations are the micro-tubular flame-assisted fuel cells. Even though there has been significant experimental research characterizing the performance and polarization losses of flame-assisted fuel cells, there is no model that describes their polarization losses. A model is thus developed and presented in this paper to assess the polarization losses and performance of flame-assisted fuel cells. Voltage and power density variation with current density are the main parameters that are analyzed in this paper. A model for calculating activation, ohmic and polarization losses is developed. Experimental parameters from previously published work like dimensions of the fuel cell layers, the fuel and oxidizer flow rates, the charge transfer coefficient and the exchange current density are used to optimize the model. The FFC is assumed to be a lumped system and a zero dimensional model is thus developed. The model was able to achieve an accuracy up to 95%, which adds to its credibility. The fuel-rich combustion exhaust composition is predicted using chemical equilibrium analysis for the equivalence ratios of 1.25 to 1.4 with intervals of 0.5 at 800°C. The model predicts that the open circuit voltage decreases from 0.94 to 0.89 for the equivalence ratios of 1.4 to 1.25, respectively, which matches experimental results. The model also predicts that the maximum power density decreases with decrease in equivalence ratio. Negligible activation loss was observed in the results while the ohmic loss didn‘t vary significantly with equivalence ratio. The concentration loss increased with decrease in equivalence ratio, which also matches with experimental results.
Haiying Guo, Chunfeng Huang, Xinlei Jia et al.
Environmental Progress & Sustainable Energy · 2023
Abstract Electricity‐generating bacteria are used as the biocatalysts of microbial fuel cells (MFCs). The power‐generating properties of electricity‐generating bacteria play an important role in organic matter degradation and electricity generation of MFCs. However, there are few electricity‐producing bacteria isolated from the anode biofilm of microbial fuel cells containing oily sludge. More importantly, the adaptability of nitrogen‐to‐phosphorus ratio, temperature and pH of the electricity‐generating bacteria were adjusted by controlled variable method. The results of this study showed that the isolated electricity‐producing bacteria ( Citrobacter freundii ) with a rod‐shaped cell, wrinkled surface, about 0.5–1.0 μm in length. The optimal nitrogen‐to‐phosphorus ratio, temperature and pH of MFCs are 5.67:1, 25°C, and pH = 7.5, Its maximum voltage and power density was up to 143.01 mV and 65 mW·m −3 , respectively. Furthermore, the growth rate of the electricity‐producing bacteria is the highest. This lays the foundation for inoculating electricity‐generating bacteria into oily sludge MFCs to improve the oil removal and power generation performance.
E. Gambino, M. Toscanesi, F. Del Prete et al.
Fuel Cells · 2017
Abstract The influence of microelectrogenesis on PAHs degradation and detoxification operated by Pseudomonadaceae, Bacillaceae, Staphylococcaceae and Enterobacteriaceae was investigated in water environment. Single chamber, air‐cathode MFCs and bioreactors were filled with the microbial pool (10 7 –10 8 CFU mL −1 ) inoculated in a 400 mL Winogradsky saline solution containing no other carbon and energy source than naphthalene (80 ppm), phenanthrene (40 ppm), pyrene (40 ppm), benzo(a)pyrene (20 ppm). MFCs and bioreactors operated at 25 °C for thirteen weeks. Power Density (PD) and Current Density (CD) outputs as well as PAHs degradation rate were measured. The toxic effect of PAHs suspension vs. Raphidocelis subcapitata was quantified by EC 1 , EC 20 , EC 50 , LOEC and NOEC calculations. The results showed a significant variability in PD and CD outputs, with highest PD of 300 mW m −3 and 25 mA m −3 . After 5 weeks, the overall PAHs concentration in MFCs decreased of a 90%. COD and TOC removal respectively of 62% and 73% after 11 weeks was achieved in MFC inoculated with bacteria (MFC 2 ). Ecotoxicological tests showed for MFCs a lower toxic effect vs. P. subcapitata when bacteria are present. Microelectrogenesis just sped up microbial metabolism rather than take advantage from the interaction of PAHs with graphite electrodes.
Khalid Zouhri, Reza S. Yassar
ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology · 2014
The molten carbonate fuel cell (MCFC) is considered one of the best technologies for stationary power. This is due to its high efficiency, medium–high operating temperature, and low emissions. The MCFC operates at a temperature range from 600oC to 700oC and normally is combined with the gas turbine (GT) as a topping cycle. This work investigates the impact of Platinum/Graphene (Pt/G) on a combined cycle of MCFC-GT by applying the first and second laws of thermodynamics. The maximum work output of the hybrid cycle is ultimately calculated to be 1350 kW. The overall exergy efficiency achieved is 59.82%. Our findings reveal that there is an average 23% gain in the maximum work output, energy and exergy efficiencies when Pt/G is used as the cathode material compared to other materials such as Platinum/Carbon (Pt/C) and Platinum/Carbon cloth (Pt/CC).
Liang Liu, Wen Yi Zhang
Applied Mechanics and Materials · 2013
In this study we investigated the use of a microbial fuel cell (MFC) to abioticlly cathodic decolorization of a model azo dye, Methyl Orange (MO). Experimental results showed that electricity could be continuously generated the MO-fed MFC and MO was successfully decolorized in the cathode. The decolorization rate was highly dependent on the catholyte pH. When pH was varied from 3.0 to 9.0, the k value in relation to MO degradation decreased from 0.298 to 0.016 μmol min -1 , and the maximum power density decreased from 34.77 to 1.51 mW m -2 . Sulfanilic acid and N,N-dimethyl-p-phenylenediamine were identified as the decolorization products of MO by HPLC-MS.
José Luz Silveira, Antonio Carlos Caetano de Souza, Márcio Evaristo da Silva
Journal of Fuel Cell Science and Technology · 2008
Fuel cell as molten carbonate fuel cell (MCFC) operates at high temperatures. Thus, cogeneration processes may be performed, generating heat for its own process or for other purposes of steam generation in the industry. The use of ethanol is one of the best options because this is a renewable and less environmentally offensive fuel, and is cheaper than oil-derived hydrocarbons, as in the case of Brazil. In that country, because of technical, environmental, and economic advantages, the use of ethanol by steam reforming process has been the most investigated process. The objective of this study is to show a thermodynamic analysis of steam reforming of ethanol, to determine the best thermodynamic conditions where the highest volumes of products are produced, making possible a higher production of energy, that is, a more efficient use of resources. To attain this objective, mass and energy balances were performed. Equilibrium constants and advance degrees were calculated to get the best thermodynamic conditions to attain higher reforming efficiency and, hence, higher electric efficiency, using the Nernst equation. The advance degree (according to Castellan 1986, Fundamentos da Fisica/Quimica, Editora LTC, Rio de Janeiro, p. 529, in Portuguese) is a coefficient that indicates the evolution of a reaction, achieving a maximum value when all the reactants’ content is used of reforming increases when the operation temperature also increases and when the operation pressure decreases. However, at atmospheric pressure (1atm), the advance degree tends to stabilize in temperatures above 700°C; that is, the volume of supplemental production of reforming products is very small with respect to high use of energy resources necessary. The use of unused ethanol is also suggested for heating of reactants before reforming. The results show the behavior of MCFC. The current density, at the same tension, is higher at 700°C than other studied temperatures such as 600 and 650°C. This fact occurs due to smaller use of hydrogen at lower temperatures that varies between 46.8% and 58.9% in temperatures between 600 and 700°C. The higher calculated current density is 280mA∕cm2. The power density increases when the volume of ethanol to be used also increases due to higher production of hydrogen. The highest produced powers at 190mA∕cm2 are 99.8, 109.8, and 113.7mW∕cm2 for 873, 923, and 973K, respectively. The thermodynamic efficiency has the objective to show the connection among operational conditions and energetic factors, which are some parameters that describe a process of internal steam reforming of ethanol.
Nathan Coutard, Ahmed Ghedjatti, Sandrine Lyonnard et al.
ECS Meeting Abstracts · 2020
Commercial proton exchange membrane fuel cells (PEMFCs) use platinum as the catalyst, a too scarce and precious metal for sustainable energy supply through PEMFCs. Pt-free catalysts are actively searched for, both at the cathode and at the anode. With huge advancements in current density, lower overpotential and higher stability in the past few years, molecular engineered bio-inspired catalysts hold promise for the next generation of PEMFC [1, 2]. Yet, their implementation in catalytic layers faces nanocomposite formulation issues [3]. Here, we use carbon nanotube immobilized DuBois nickel catalysts to exemplify how self-assembly at the mesoscale affects performances of H 2 oxidation anodes. Copied on the conserved functional features of the active site of hydrogenases, the nickel catalysts created by Dubois et al. [4] show impressive turn-over frequency with no over-potential for hydrogen oxidation in solution. Not only has the central part of the catalyst, but also its outer sphere has a strong influence on the catalytic capacity [5]. Modification of the outer sphere can be used to immobilize the catalyst on a conductive matrix [6-8], a requirement for further implementation in PEMFC [9]. However, long-term ion transport in PEMFC requires creating ion conductive paths in the electrode, a task usually fulfilled by the addition of an ionomer. Although it allowed us to assemble the first fully Pt-free PEMFC [3], the current density was very low when the anode contained ionomer. The electrode microstructure thus appears critical to the system performance, yet it was hardly studied. The figure includes a STEM picture of a carbon nanotube-ionomer mixture showing the thin film formed by the self-organized ionomer, and the schemes of the catalyst structure and of the ionomer structure. Here, we show that molecular engineering coupled with three-dimensional structuring of the carbon electrode plays a major role on the catalytic activity through enhancement of catalyst grafting and substrate/product diffusion inside the electrode. In particular, we compare the effect of Nafion ionomer addition on the performances of bioinspired catalytic layers produced via three distinct surface chemistries [6-9]. We use microscopy as well as small angle neutron scattering techniques to characterize the self-assembly of the ionomer [10] with the carbon nanotubes/catalyst composite. A strong correlation appears between current drop in the presence of ionomer, and absence of ionomer hydrophilic/hydrophobic nanostructure. We propose a model that describes how the surface charge of the functionalized nanotubes drives the structuration of the Nafion ionomer and impacts diffusion of protons and gas to and from catalytic centres. [1] N. Coutard, N. Kaeffer, V. Artero, Chem. Commun ., 2016, 52, 13728-13748. [2] F. Jaouen, D. Jones, N. Coutard, V. Artero, P. Strasser, A. Kucernak, Johnson Matthey Technology Review , 2018, 62, 231-255. [3] P.D. Tran, A. Morozan, S. Archambault, J. Heidkamp, P. Chenevier, H. Dau, M. Fontecave, A. Martinent, B. Jousselme, V. Artero, Chem. Sci., 2015, 6, 2050-2053. [4] M. Rakowski Dubois and D. L. Dubois, Acc. Chem. Res., 2009, 42, 1974–1982 [5] A. Dutta, J.A.S. Roberts, W.J. Shaw, Angew. Chem. Int . 2014, 53, 6487-6491 [6] A. Le Goff, V. Artero, B. Jousselme, P.D. Tran, N. Guillet, R. Metaye, A. Fihri, S. Palacin, M. Fontecave, Science , 2009, 326, 1384-1387. [7] P.D. Tran, A. Le Goff, J. Heidkamp, B. Jousselme, N. Guillet, S. Palacin, H. Dau, M. Fontecave, V. Artero, Angew. Chem. Int. Ed., 2011, 50, 1371-1374. [8] T.N. Huan, R.T. Jane, A. Benayad, L. Guetaz, P.D. Tran, V. Artero, Energy Environ. Sci., 2016, 9, 940-947. [9] S. Gentil, N. Lalaoui, A. Dutta, Y. Nedellec, S. Cosnier, W.J. Shaw, V. Artero, A. Le Goff, Angew. Chem. Int. Ed. , 2017, 56, 1845-1849 [10] L. Rubatat, G. Gebel, O. Diat, Macromolecules 2004, 37, 7772 Figure 1
Ahmet Erensoy, Nurettin Çek
Polymers · 2021
Microbial fuel cells (MFCs) have attracted attention by directly converting the bioelectrochemical energy possessed by the organic materials that make up the biomass into electrical energy. In this study, the relationship between the biofilm formed on the titanium-based anode electrode surface, and the chemical composition of the substrate, the energy source of MFC, was investigated. For this, MFCs were made by using poplar wood shavings rich in organic material as the substrate, titanium-based material as the anode electrode, and natural soil as bacterial habitat. Three types of MFCs containing 1%, 10%, and 20% poplar wood shavings by weight were made and named P1-MFC, P2-MFC, and P3-MFC, respectively. According to electrochemical analysis, P3-MFC provided the highest open circuit voltage with 490 mV value, and the highest power density with 5.11 mW/m2 value compared to other MFCs. According to optical microscopy examinations, there were Bacillus and Coccus species of bacteria in the soil structure, and these bacteria also existed around the fiber of poplar wood shavings in MFCs. Scanning electron microscopy (SEM), energy-dispersive spectrum (EDS), and Fourier transform infrared spectroscopy (FTIR) analysis showed that MFCs formed biofilm in the titanium-based anode, and the chemical composition of this biofilm with poplar tree was similar. As a result, due to the catalysis reactions of bacteria, the titanium-based anode electrode surface was coated with polymer biofilm released from poplar wood shavings.
Haiying Guo, Xie Shuixiang, Huang Chunfeng et al.
Research Square · 2022
Abstract Electricity-generating bacteria as biocatalysts for microbial fuel cells (MFCs), and their species and power generation performance determine the performance of the MFC for pollution control and power generation. For that purpose, an electricity-generating bacteria isolated from the oily sludge MFCs, and adjusted the adaptability of nitrogen-to-phosphorus ratio (3.67:1, 4.67:1, 5.67:1, and 6.67:1), temperature (5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃) and pH (pH = 6, 6.5, 7, 7.5, 8). The results of this study showed that electricity-generating bacteria was identified as Bacillus cereus , with a rod-shaped cell, about 0.5-1.0 µm in length. The optimal nitrogen-phosphorus ratio, temperature and pH of MFCs were 4.67:1, 25 ℃ and pH = 7, respectively, and its output voltage was up to 168.05 mV. The study of this functional bacteria will provide beneficial assistance for the improvement of oil removal and power generation performance of oily sludge MFCs.
Daniel J. Fenton, Jeffrey J. Gagliardo, Thomas A. Trabold
ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology · 2014
To achieve optimal performance of proton exchange membrane (PEM) fuel cells, effective water management is crucial. Cells need to be fabricated to operate over wide ranges of current density and cell temperature. To investigate these design and operational conditions, the present experiment utilized neutron radiography for measurement of in-situ water volumes of operating PEM fuel cells under varying operating conditions. Fuel cell performance was found to be generally inversely correlated to liquid water volume in the active area. High water concentrations restrict narrow flow field channels, limiting the reactant flow, and causing the development of performance-reducing liquid water blockages (slugs). The analysis was performed both quantitatively and qualitatively to compare the overall liquid water volume within the cell to the flow field geometry. The neutron image analysis results revealed interesting trends related to water volume as a function of time. At temperatures greater than 25°C, the total liquid water volume at start-up in the active area was the lowest at 1.5 A/cm2. At 25°C, 0.1 A/cm2 performed with the least amount of liquid water accumulation. However, as the reaction progressed at temperatures above 25°C, there was a crossover point where 0.1 A/cm2 accumulated less water than 1.5 A/cm2. The higher the temperature, the longer the time required to reach this crossover point. Results from the current density analysis showed a minimization of water slugs at 1.5 A/cm2, while the temperature analysis showed unexpectedly that, independent of current density, the condition with lowest water volume was always 35°C.
M. H. Tsai, Y. Y. Yan, H. S. Chu et al.
2nd International Conference on Fuel Cell Science, Engineering and Technology · 2003
A 3kW PEMFC power generation system is developed by Energy and Resources Laboratories in 2002. This system integrates hydrogen storage, fuel reformer, power conversion, hot water tank as well as a 3kW PEMFC stack. The power generation efficiency at 30% and total energy efficiency with hot water recovery at 67% are designed. The stack is key component of this system, and its performance is tested and analyzed before it is integrated into the system. This paper presents its performance in I-V polarization curves with controlling parameters such as fuel cell operating temperature, air humidity, hydrogen humidity and stoichimetric ratio of air. Detailed discussions are given for the effect of each parameter on stack’s performance.
A. Andreičiks, I. Steiks, O. Krievs
Latvian Journal of Physics and Technical Sciences · 2013
Abstract In domestic applications the low DC output voltage of a hydrogen fuel cell used as the main power supply or a backup power source has to be matched to the level and frequency of the AC voltage of utility grid. The interfacing power converter system usually consists of a DC/DC converter and an inverter. In this work, a DC/DC step-up converter stage is designed for interfacing a 5kW proton exchange membrane (PEM) fuel cell. The losses of DC/DC conversion are estimated and, basing on the relevant analysis, the most appropriate configuration of converter modules is selected for a DC/DC converter stage of increased efficiency. The authors present the results of experimental analysis and simulation for the selected configuration of four double inductor step-up push-pull converter modules
Shengpeng Chen, Aina Tian, Chaoling Han
Processes · 2023
The commercial proton exchange membrane fuel cell (PEMFC) system needs to be equipped with the capacity to survive a harsh environment, including sub-freezing temperatures. The cold start of PEMFC brings about great technical challenges, mainly due to the ice blockage in the components, which seriously hinders the multi physical transmission process. A multiscale, two-dimensional model was established to explore the gas purging in PEMFC under different electrochemical reaction intensities. The results indicate that the optimal case is obtained by B3-1 with a power density of 0.796 W cm−2, and the power density increases first and then decreases, followed by stoichiometric flow ratio (ξ) changes. It is worth noting that the water mole fraction in the PEM is closely related to the water concentration gradient. However, the differences in the initial water distribution in porous media have little bearing on the condensed water in the gas channel, and the liquid water in the gas diffusion layer (GDL) is preferably carried away ahead of other porous parts. The results also show that the increase in the purge speed and temperature can remove the excess water on GDL and the catalytic layer in a short time. For a nitrogen-based purge, the operating condition in case B3-1 is shown as the best strategy based on the output performance and economic analysis during the shutdown and purge process.