bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Permeation Study in Thin and Ultra-Thin Ionomer Films
Authors: Tesfaye Meron , McCloskey Bryan D , Weber Adam Z 
Published: February 2020

Commercially available perfluorinated sulfonic-acid (PFSA) ionomers like Nafion and 3M-ionomer are widely used both as electrolyte membranes and as conductive binders in electrode structures in polymer-electrolyte fuel cells (PEFCs). However, these ionomers are also major contributors to unexplained large mass-transfer overpotentials at high current densities in PEFCs[1]. Bulk ionomer films (> 1 µm thickness) in electrolyte membranes provide charge separation, ion transport, and prevent reactant/product gas crossover. For increased performance in PEFCs, bulk ionomers of high conductivity, high selectivity, and low gas permeability are desired. In electrode structures, thin (< 1 µm) and ultra-thin (< 0.025 µm) films serve as ionic charge carriers to catalytic sites. Here, low resistance to gas transport for increased supply of reactants to catalytic sites is required. These conflicting properties required for two separate functions of ionomers in bulk and thin film make optimizing mass-transport very difficult. Complicating ionomer and transport optimization even more, conditions such as temperature, humidity, casting method, annealing, and confinement result in thin-film properties that deviate from those of bulk. Therefore, thorough understanding of mass transport resistances in both bulk and thin film ionomers is key in increasing efficiency in PEFCs.
Significant amount of work has been done to study gas transport and permeation in bulk ionomer films [2,3]. However, much remains to be explored in thin and ultra-thin ionomer films. In this talk, we present data for gas permeation in thin and ultra-thin PFSA films. Thin ionomer films are supported on well studied, highly permeable rubbery poly(dimethylsiloxane) (PDMS). Dry O2, N2, H2 and CO2 permeability of the ionomer film is measured using a constant-volume, variable-pressure permeation system. Experimental results and variations of permeability of thin films from bulk films as a function of temperature and thickness will be presented. In addition, to tackle the complex and not fully understood effect of water in gas transport, an experimental set-up and approach for measuring effects of humidity on gas permeability of thin films will also be presented.

Acknowledgement

We would like to thank Norman Su for providing assistance in permeation system assembly and operation. This work made use of facilities at the Biomolecular Nanotechnology Center at University of California, Berkeley and the Molecular Foundry at Lawrence Berkeley National Laboratory. This work was funded in part by the University of California Chancellor's Graduate Fellowship and the Assistant Secretary for Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U. S. Department of Energy under contract number DE-AC02-05CH11231.

References

[1]Nonoyama, N. et al (2011). Journal of Electrochemical Society. 158(4)
[2] Buchi FN, Wakizoe M, Srinivasan S. J Electrochem Soc 1996;143:927–32.
[3] Ogumi Z, Takehara Z, Yoshizawa S. J Electrochem Soc 1984;131:769–73
Multiple Advance Diagnostics to Probe the Effect of Balance of Plant Materials on Fuel Cell Performance
Authors: Staub Charles B , Christ Jason M , Bender Guido , Macomber Clay S. , Wang Heli , Dinh Huyen N 
Published: February 2020

Extensive research on fuel cell stack materials has led to advances in lower cost, high performing materials. With the decrease in the cost of stack materials, lowering the cost of the balance of plant (BOP) components has increased in importance. In order to decrease the overall cost of the automotive and stationary fuel cell systems and make them as competitive as possible, low-cost system component materials that provide similar function, performance and durability are needed. However, intelligently selecting low cost materials for application in polymer electrolyte membrane fuel cell (PEMFC) systems requires understanding the potential adverse effects that system contaminants may have on the fuel cell performance and durability. Limited work in this area has been conducted to-date.
There are many prospective BOP materials that can be used in fuel cell systems. Our material selection was based on the material’s physical properties (i.e., whether it will be stable in fuel cell operating conditions), commercial availability, cost and input from OEMs and fuel cell system manufacturer. Families of material chosen for the study include structural materials, elastomers for seals and (sub)gaskets, and assembly aids (adhesives, lubricants).
Two types of low cost structural plastic materials – a polythlalamide and a polyamide – were studied. Leachates obtained from these plastics were a mixture of organics, inorganics, and ions and were introduced to a working fuel cell to determine their effect on the fuel cells performance. Organics that were identified in the leachate solutions via gas chromatography mass spectrometry (GCMS) include 1,8 Diazacyclotetradecane-2,7-dione (DCTDD), aniline, and caprolactam. These plastic materials also released anions: chloride, phosphate, nitrates, and sulfates. In-situmeasurements such as infusion, cyclic voltammetry, impedance spectroscopy, and I-V curves were carried out to better characterize the contaminants effects of the mixtures of compounds in the extracts. The effect of the individual organic model compound (caprolactam), anion (sulfate) and mixtures of the two species were also studied to better understand the contamination mechanisms of specific species and their interaction with one another.
This presentation will also briefly describe the ex-situ electrochemical quartz crystal microbalance (EQCMB) technique used to study the adsorption effect of organic compounds, derived from system contaminants, on Pt surface. EQCMB was used to measure the change in mass of the electrode as a function of potential.
The authors would like to acknowledge funding from the U.S. Department of Energy EERE Fuel Cell Technologies Office, under Contract No. AC36-08GO28308 with the National Renewable Energy Laboratory and collaborations with colleagues at GM and 3M. Structural plastic materials were provided by GM and membrane degradation products for this study were provided by 3M.
Pt/Metal Oxide Micro-Nanostructures for Chemical-Electrical Signal Transduction
Authors: Ray Nathan J , Karpov Eduard G 
Published: February 2020

Investigation of heterogeneous catalysis using bifunctional systems of nanodispersed Pt on porous oxide structures is important for a broad range of applications including photocatalysis, fuel cells, solid state chemical sensors, and others. Active transducers exhibit great potential through their ability to convert surface-released chemical energy into electrical signal. We report on a class of nanocomposite mesoporous systems that generate this electrical signal when subjected to catalytic oxyhydrogen reactions of their surface; these systems include, but are not limited to, mesoporous TiO2 decorated with electrically continuous arrays (meshes) of Pt nanoparticles. It has been proposed that the proton spillover hypothesis of the electromotive force in the mesoporous chemical-electrical transducer nanostructure leads to a multi-modal nature of the “chemicurrent” - non-thermal electrical signals related to hot electron and e-h pair generation. Structural and surface morphology play a pivotal role in the generation, transport, and recombination of electrical charge in these bifunctional catalytic systems. In this presentation, we discuss plasma electrolytic oxidation procedures that allow for the further optimization of mesoporous nanocomposite structures by controlling parameters such as pore density within the samples.
Electrochemical Reduction of 2,2′,6,6′-Tetrabromobisphenol A at Silver Cathodes in Dimethylformamide
Authors: Gerroll Benjamin , Peters Dennis G 
Published: February 2020

2,2′,6,6′-Tetrabromobisphenol A (TBBPA) is a brominated flame retardant that is bonded chemically to epoxy resins in circuit boards and that is added to high-impact polystyrenes. TBBPA is found ubiquitously throughout the environment in sewage runoffs and in water and soil samples, as well as in living organisms. There have been many documented methods for the degradation of TBBPA, including both chemical and physical methods. In this study we have focused on the electrochemical degradation of TBBPA at silver electrodes in dimethylformamide (DMF) containing 0.10 M tetramethylammonium tetrafluoroborate (TMABF4). Initially, cyclic voltammograms were recorded to characterize the electrochemical behavior of TBBPA at both glassy carbon and silver cathodes, as shown in the accompanying figure. At glassy carbon, only two irreversible cathodic peaks are observed. On the other hand, reduction of TBBPA at a silver cathode gives rise to three cathodic peaks, which appear at potentials significantly more positive than for glassy carbon. To investigate the possible debromination of TBBPA, controlled-potential (bulk) electrolyses have been performed with a silver gauze electrode in a DMF–0.10 M TMABF4. Using GC–MS for the separation, identification, and quantitation of products arising from bulk electrolyses, we have determined that mixtures of mono-, di-, and tribrominated species are produced.

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Electrochemical Behavior of Nitrobenzene in Aqueous CTAB
Authors: Haque Inam-ul 
Published: February 2020

A mechanistic study of the electroreduction of nitrobenzene was undertaken following previously reported voltammetric investigations of nitrobenzene reduction on bare and dioctadecyldimethylammonium chloride (DODAC) covered platinum electrode [1]. The electrochemical reduction of nitrobenzene in aqueous micellar solution of cetyltrimethylammonium bromide (CTAB) at platinum electrode using cyclic voltammetry revealed two distinct cathodic and anodic peaks with interpeak separation of about 60-65 mV indicating a reversible/quasi-reversible charge transfer reaction pertaining to one electron couple of ArNO2/ArNO2

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as reported in literature [2-6]. Additional interpretation of experimental cyclic voltammogram was done by using digital simulation. Diffusion co-efficient values of nitrobenzene calculated using Randle-Sevcik equation were found close to the reported values [5-6].
References
(1) Haque, I. U.; Tariq, M. J. Chem. Soc. Pak.
2011, 33, 529-534.
(2) Sripriya, R.; Chandrasekaran, M.; Noel, M. Colloid Polym Sci.
2006, 285, 39-48.
(3) Ernst, S.; Ward, K. R; Norman, S. E.; Hardacre, C.; Compton, R. G. Phys. Chem. Chem. Phys. 2013, 15, 6382-6389.
(4) Jara-Ulloa, P.; Nunez-Vergara, L. J.; Squella, J. A. Electroanal. 2007, 19, 1490-1495.
(5) Smith, W. H.; Bard, A. J. J. Am. Chem. Soc. 1975, 97, 5203-5210.
(6) Kaifer, A. E.; Bard, A. J. J. Phys. Chem., 1985, 89, 4876-4880.
Limits of Li-Ion Batteries for Public Transportation
Authors: Patey Timothy John 
Published: February 2020

Accelerating a 50-ton rather than a 1-ton electric vehicle presents new scientific and engineering challenges. In view of this, our work discusses the power limits of Li-ion batteries as on-board energy storage devices in traction systems used in public transportation. This is based on a thermal analysis of a high power Li-ion battery and an aging/thermal model of it. Included within this process are the following details:
1) General analysis of required heat transfer coefficients.
2) Estimation of internal thermal conductivity along and parallel to electrodes.
3) Use of a thermal network model to calculate internal temperature.
Based on this approach, routes to develop higher power Li-ion batteries are discussed based on our current understanding of the electrochemical and heat transfer limitations. A proposal on future electrochemical devices, designed especially for public transportation, is also discussed in detail.

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The Deep Sea Water and Heat Energy of Thermoelectric Generation Study
Authors: Chen Meng Chu 
Published: February 2020

This study is a preliminary evaluation of the potential for using deep sea water and solar energy (or hot-spring water) source to economic benefits of thermoelectric power in Taiwan. we investigated that solar energy and high temperature spring water was replaced to the surface sea water to increase the temperature difference (70~85oC). Use of innovative, green, renewable energy resource enables the City (Town) to reduce its demand for electricity by approximately 0.5 million kilowatt hours annually (reduction of up to 65 per cent compared to conventional power system, reduced electricity demand and consequently lower emissions of air pollutants and greenhouse gases.) We propose an energy-balanced mathematical model considering thermal sources and heat effects to precisely evaluate the capacity of thermoelectric power systems.
The research is low temperature of the use the deep ocean water establishes thermoelectric power system, applies the building already some power system in the substitution, not can only enrich DSW the multi-dimensional use, can gain the energy conservation to reduce the carbon essence benefit.
Modulating Electron Transfer Dynamics Via Graphene Interactions in Donor-Acceptor Systems
Authors: D'Souza Francis , Lim Gary N. , KC Chandra 
Published: February 2020

Sequential electron transfer or electron transfer/hole transfer between energetically well-positioned entities of photosynthetic reaction center donor-acceptor models is one of the commonly employed mechanisms to generate long-lived charge separated states. Wealth of information, applicable towards light energy harvesting and building optoelectronic devices, has been acquired from such studies. In the present study, we report charge stabilization in multi-modular donor-acceptor pentads comprised of phenothiazine, subphthalocyanine and fullerene as molecular components.1 In these pentads, the subphthalocyanine and fullerene serve as primary electron donor and acceptor, while the phenothiazine entities act as secondary hole transferring agents. The newly synthesized compounds were characterized by optical absorption and emission, computational and electrochemical methods. The redox potentials measured using differential pulse voltammetry were used to estimate free-energy changes for charge separation, hole migration, and charge recombination processes. Using femto- and nanosecond transient absorption techniques, evidence for charge separation, and kinetics of charge separation and recombination were obtained in polar benzonitrile and nonpolar toluene solvents. The kinetic data obtained by analyzing the time profiles of the radical ions revealed occurrence of ultrafast charge separation and relatively slow charge recombination processes as a result of electron transfer-hole shift mechanism in these pentads. The measured rate of charge separation, k
CS were in the range of 1.2 - 4.4 x 1010 s-1 while the rate of charge recombination, k
CR were in the range of 1.3 - 5.4 x 106 s-1, depending upon the design and solvent polarity, revealing charge stabilization in the pentads. Further, by the interaction of phenothiazine entities of the triad with graphene, modulation of electron transfer events has been accomplished. Details of these investigations will be presented.

1KC, C. B.; Lim, G. N.; Zandler, M. E.; D’Souza, F., Org. Letts. 2013, 15, 4612-4615.
Pre-Coated Ce/Co-Coated Steel: Mitigating Cr Vaporization, Increasing Corrosion Resistance at Competitive Cost
Authors: Falk Windisch Hannes , Mertzidis Ioannis , Svensson Jan-Erik , Froitzheim Jan 
Published: February 2020

Cr vaporization and oxide scale growth are probably the two most detrimental degradation mechanisms associated to Cr2O3-forming alloys as interconnect material in SOFC. Different type of perovskite or spinel coatings are commonly used to mitigate Cr vaporization. Furthermore a number of studies have suggested that reactive element coatings (Ce, La, Hf) can reduce the oxidation rate of Cr2O3-forming alloys. However, the use of coatings increases cost due to addition processing and handling costs.
The present study investigates the effectiveness of thin Ce and Co Physical Vapor Deposited (PVD) coatings with respect to Cr vaporization, corrosion resistance and Area Specific Resistance (ASR). The coatings were applied in a continuous roll-to-roll process which allows for high volumes.
The use of pre-coated interconnects is thus more economic than a batch process. However, a consequence of the pre-coated concept is that the coating is subject to deformation when the pre-coated steel is pressed into the interconnect shape.
Therefore this study also investigates the effect of deformation on the coating. Coated steel strips were bi- and uniaxially deformed. Furthermore a commercially used interconnect shape is investigated and the effects on Cr evaporation and corrosion are studied: Cr vaporization was measured in an air-3% H2O environment at 850 °C for 336 h. The results revealed that when the pre-coated steel was deformed, large cracks were formed. However, upon exposure those cracks did heal forming a continuous surface oxide rich in Co and Mn. As an effect of the rapid healing, no increase in Cr vaporization was measured for the pre-coated material.
In Situ Tailored Nickel Nano-Catalyst Layer for Internal Reforming Hydrocarbon Fueled SOFCs
Authors: Myung Jaeha , Neagu Dragos , Tham Mark , Irvine John T. S. 
Published: February 2020

Solid oxide fuel cells (SOFCs) have been strongly attracted as the next energy technology due to their high efficiency and eco-friendly energy convertor. SOFCs do not only directly convert to electricity from hydrogen, also from various hydrocarbon fuels such as methane, propane, and so on. However, the conventional Ni cermet anode suffers carbon deposition when directly used with hydrocarbon fuels because of pyrolysis and Boudouard reactions.
In this work, non-stoichiometry perovskite (La0.8Ce0.1Ni0.4Ti0.6O3) as reforming layer can lead to Ni nano particle exsolution with homogenous distribution and high population in reduction atmosphere. This catalyst layer was applied on Ni-GDC anode supported single cell to prevent carbon deposition through reforming hydrocarbon fuel at outer surface.
The catalyst layer showed excellent attachment with Ni-GDC anode and resistance of carbon deposition. The performance of Ni–GDC anode-supported single cells with catalyst layer was about 1 W/cm2 in hydrogen fuel as similar as without catalyst layer. We are also analyzing of cell performance in dry methane and partial oxidation of methane to clarify the presence of nano nickel particles in the catalyst layer and its effect on the electrode-catalytic activity and polarization resistance.
Advanced 3D Imaging and Analysis of SOFC Electrodes
Authors: Tariq Farid , Kishimoto Masashi , Cui Guansen , Yufit Vladimir , Lomberg Marina , Ruiz-Trejo Enrique , Chen Zhangwei , Brandon Nigel P. 
Published: February 2020

Meeting increasing energy demands, storage demands and energy portability in a clean efficient manner will be expedited through an ability to directly image and analyse solid oxide fuel cell (SOFC) materials and components. In particular, the performance of SOFC electrodes is dependent on their nano/micro-structure as electrochemical reactions and transport phenomena are strongly affected by their complex porous microstructure. Furthermore, during processing or operation, microstructural evolution may degrade electrochemical performance.
Tomographic techniques allow the 3D imaging and characterisation of complex microstructures at length scales down towards tens of nanometers; which are inadequately described in 2D. While performance is acknowledged to be dependent on reactions at electrode surfaces and interfaces, the detailed nature of these in technological electrodes is still not fully understood.
Here we use tomographic techniques to probe the 3D SOFC electrode structure at nanometer to micrometer length scales. For the first time characterisation of specific necks and interfaces within SOFC electrodes is derived. Micro/nano structural changes are followed to facilitate understanding the differences which occur with shape, structures and morphology at high resolution. These are correlated with measured experimental values to provide insight into microstructure-property relationships. In doing so, the engineering of tailored electrodes during 3D printing is afforded.
When coupled with electrochemical and thermo-mechanical computational models, the results show that nano/microstructural and compositional variations can significantly affect performance of SOFC electrodes. This coupled approach provides important insights for electrode design and understanding the sources of performance degradation.

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­­Additive Manufacturing for Solid Oxide Cell Electrode Fabrication
Authors: Lomberg Marina , Boldrin Paul , Tariq Farid , Offer Greg , Wu Billy , Brandon Nigel P. 
Published: February 2020

Electrode microstructure plays a critical role in determining the electrochemical performance and durability of Solid Oxide Cells. Additive manufacturing can potentially offer a highly-defined electrode microstructure, as well as fast and reproducible electrode fabrication. Selective laser sintering (SLS) is an additive manufacturing technique in which the three-dimensional structures are created by bonding subsequent layers of powder using laser power.
Although selective laser sintering can be applied to a wide range of materials, including metals and ceramics, the scientific and technical aspects of the manufacturing parameters and their impact on microstructural evolution during the process are not well understood.
In the present study this novel approach for electrode fabrication was evaluated by conducting a proof of concept study. A Ni-patterned fuel electrode was laser sintered on a YSZ substrate. The optimization process of laser parameters (laser sintering rate and laser power) and the electrochemical results of a full cell with laser sintered electrode are presented. The challenges and prospects of using selective laser sintering for SOC fabrication (for example, to create electrodes with unique 3D hierarchical porous structures) are discussed.

Figure 1