bluuebunny/crossref_metadata_2025 huggingface dataset:
Deactivation and Recovery of Pt/C with Commercial Glycol-Based Coolants in Rotating Disk Electrodes and Membrane Electrode Assemblies
Authors: Gould Benjamin D. , Garsany Yannick , Swider-Lyons Karen
Published: September 2014

The performance of proton exchange membrane fuel cells (PEMFCs) can degrade when exposed to glycol-based coolants through leaks in seals or cracks in carbon bipolar plates. We study the poisoning of Pt/Carbon electrocatalysts by a glycol (1, 3 propanediol)-based coolant containing an ethoxylated nonylphenol surfactant, and azole- or polyol-based non-ionic corrosion inhibitors both by rotating disk electrode (RDE) voltammetry and in a membrane electrode assembly (MEA) in a fuel cell. There is good agreement between RDE and MEA experiments. The RDE results show that the azole corrosion inhibitor irreversibly deactivates the Pt/Vulcan carbon electrocatalyst, while exposure to all of the other coolant components is reversible. The MEA measurements also show a permanent 30% loss in mass activity after exposure to the azole-containing coolants, and provide the additional insight that repeated coolant exposure causes Pt surface area loss, and thereby permanent performance degradation.
In Situ Soft X-ray Visualization of Liquid Water Distribution in a PEMFC with VGCF-Modified MPL
Authors: Jao Ting-Chu , Sasabe Takashi , Deevanhxay Phengxay , Tsushima Shohji , Hirai Shuichiro
Published: September 2014

In proton exchange membrane fuel cells (PEMFCs), appropriate water management is critical to achieve high power density operation with increased robustness. For this purpose, soft X-ray radiography has been used in this study because it has been proved to be a powerful incitement for observing liquid water in PEMFCs. In this study, we focused our attention on micro porous layers (MPLs) with vapor growth carbon fiber (VGCF) impregnated in the MEA. In the experiment, we fabricated VGCF MPL coated on gas diffusion substrate (SIGRACET® 24BA). We also used commercial gas diffusion layer (SIGRACET® 24BC) for comparison. In situ visualization of liquid water distribution in both MEAs by soft X-ray radiography clearly shows their difference. The water tends to accumulate both at GDS and MPL for 24BC; the water tends to accumulate at GDS for VGCF.
Investigation of Interfacial Water Transport at the Gas Diffusion Media by Neutron Radiography
Authors: Kotaka Toshikazu , Tabuchi Yuichiro , Pasaogullari Ugur , Wang Chao-Yang
Published: September 2014

For cost reduction of fuel cell, it is necessary to realize high current density operation, which requires a thorough understanding of mass transport. However, especially interfacial liquid water transport between carbon paper (CP), micro porous layer (MPL), and catalyst layer (CL) are not fully understood. Coupled cell performance evaluation, liquid water visualization by neutron radiography and numerical modeling were performed with three types of gas diffusion media (GDM): MPL free; CP with MPL; and CP free. It revealed that the presence of a gap at the CL-GDM interface has a significant effect on water accumulation and that the MPL could minimize this effect. At the same time, CP free case showed the best performance and the lowest liquid water content due to multiple impacts of interfacial liquid water transport both at CL-MPL and MPL-channel interfaces. These results confirm the importance of interfacial design between each component of fuel cell for further cost reduction.
(Invited) Recent Advances on Energy Conversion Using Microfluidic Fuel Cells Technology, Case: Glucose Membraneless Micro Fuel Cell Stack
Authors: Cuevas-Muñiz Francisco Mherande , Chavez Abraham Ulises , Guerra-Balcázar Minerva , Godínez Mora-Tovar Luis Arturo , Ledesma-García Janet , Arriaga Luis Gerardo
Published: September 2014

A no-flow membraneless fuel cell stack for energy conversion is evaluated integrating bimetallic materials as selective electrocatalysts based on Ag-alloys. TGA and XRF characterization allowed know the composition of the catalysts. XPS studies were performed to determinate the electronic state of the metals in the electrocatalyst. The stack was machined using low-cost techniques and non-expensive materials. The batch feeding mechanism considers a unique fluid composed of glucose and oxygen in alkaline medium at room temperature. The stack was able of delivering up to 60 µW for 10 minutes on a single charge of the fuel-oxidant mixture at room temperature. When the stack was fueled by glucose at 10 mM, the device harvested 0.053 mAh after 40 minutes of operation; furthermore when it was fed by glucose at 100 mM a 0.065 mAh charge was reached after 75 minutes. The results encourage the possibility of building a membraneless stack regardless of external power supplies such as micro-pumps.
(Invited) From PEM Fuel Cell Design to Biological Fuel Cells: The Status of Systems Development for Biological Fuel Cells
Authors: Rasmussen Michelle , Milton Ross D , Hickey David P , Reid Russ C. , Minteer Shelley D.
Published: September 2014

The field of biological fuel cells has been exponentially expanding over the last decade. As the fundamental science has evolved and improved electrode performance, more focus has been paid to engineering design of the biological fuel cell. This review details the transition from U-cell designs to MEAs to other form factor-based biological fuel cell designs, depending on the energy applications.
(Invited) Manufacturing Readiness and Cost Impacts for PEM Stack and Balance of Plant
Authors: Wheeler Douglas , Ulsh Michael
Published: September 2014

The results of two Manufacturing Readiness Assessments of PEM fuel cell stacks and material handling equipment (MHE) and backup power (BUP) PEM fuel cell systems are given. Design modifications of fuel cell systems were made because the initial, 2008 designs did not fully meet the operational requirements of the markets. This situation indicates the 2008 risk elements were overstated.For 2010 BUP and MHE fuel cell systems, manufacturers had not reached the Low Rate Initial Production (LRIP) defined in the 2008 MRA Report at 1,000 units per year per manufacturer.For fuel cell stacks, LRIP was demonstrated by more than one manufacturer.The federal tax incentive program has compensated for the initial high cost of fuel cell systems.The Balance-of-Plant (BOP) has not evolved as rapidly as the PEM fuel cell stack manufacturing readiness.The BOP in 2014 is as costly as the fuel cell stack for MHE applications.
Application of Carbon Coated Stainless Steel for Bipolar Plate in Proton Exchange Membrane Fuel Cell
Authors: Hsieh HoYen , Wang Wen-Lin , Lan ChaoHo
Published: September 2014

A polymer electrolyte membrane fuel cell (PEMFC) which uses stainless steel as a bipolar plate has many advantages over conventional machined graphite. Austenitic stainless steel 316L is a traditional candidate for metal bipolar plates. During a long operation time, metal oxide formation leads to contact resistance, and metal dissolution can cause contamination of the membrane electrode assembly (MEA). A pure Carbon was coated on the surface of Stainless steel and provided a good anticorrosion layer. The carbon film has a low area specific resistance compared to the composite coating because it has a high surface conductivity. In addition, The ICR between the carbon-coated SS316 and the carbon paper is 1100–3000 mΩ-cm2 under compaction forces between 20 and 280 N/cm2. The carbon-coated SS316L shows good corrosion resistance in the simulated PEMFC environment. After 4000hrs of testing time, the power density of a single cell was less than 1% decline. Therefore, the carbon-coated SS316L has an excellent durability property.
Performance of 3D-Printed Fuel Cells and Stacks
Authors: Gould Benjamin D. , Rodgers Joseph A. , Schuette MIchael , Bethune Keith , Louis Shaquille , Rocheleau Richard , Swider-Lyons Karen
Published: September 2014

Additive manufacturing (AM) is being touted as a possible tool for rapid prototyping fuel cell bipolar plate (BPP) designs. We use the AM method of direct metal laser sintering (DMLS) to make 21 cm2 titanium-alloy BPPs with embedded flow channels. The surface of the BPPs is then polished to the appropriate roughness and coated with a conductive corrosion barrier. The coated BPPs are assembled with the appropriate seals, catalyst coated membranes and gas diffusion layers into a 40-cell stack and tested. The resulting 400 W fuel cell stack power is 20% less than expected because of inadequate flatness of several of the DMLS BPPs as determined by white light profilometry, leading to high contact resistance. While DMLS clearly shows the benefit of being able to make complex flow fields and hollow parts with no welds, more work is needed toward reducing the weight and increasing the flatness of BPPs made by AM.
Novel Dead-Ended Anode Design for Self-Regulating Humidification in an Air-Breathing H2-PEM Fuel Cell
Authors: Ferreira-Aparicio Paloma , Chaparro Antonio M.
Published: September 2014

A novel design of anode chamber has been implemented in an air-breathing a PEM fuel cell allowing for stable long-term operation under strictly stoichiometric H2 consumption with 100% fuel utilization. The developed model allows for selective exchange of water between the anode and the external environment by means of a gas-tight polymer. The gas-tight drying film provides a suitable way for excess water removal from the anode. The present study analyzes in detail the operation of this anode configuration. Electrochemical impedance spectroscopy and polarization hysteresis curves have been used to explore the cell behavior under different environmental conditions of temperature and relative humidity controlled by means of a climate chamber. The results are compared with those obtained for a similar cell assembled with a conventional anode operating under continuous flow and dead-ended anode under periodical purge. The stable long-term operation of the 2W cell with this novel design ensures 100% efficiency in fuel utilization.
Low Cost Bipolar Plates for Large Scale PEM Electrolyzers
Authors: Gago Aldo Saul , Ansar Asif Syed , Gazdzicki Pawel , Wagner Norbert , Arnold Johannes , Friedrich Kaspar Andreas
Published: September 2014

PEM electrolysis is a promising technology for large scale storage of surplus electricity, though it is still costly mainly due to the manufacture of large area and high purity Ti bipolar plates (BPP). In this work we have developed an Au/Ti coating deposited by electrodeposition/thermal spraying on stainless steel BPP. The coating was physically characterized with SEM and electro-chemically evaluated in simulated anode conditions. Interfacial contact resistance (ICR) vs. compaction pressure measurements showed that the coating is highly conductive. It successfully protected the stainless steel substrate from corrosion. However, the Au modification detached after 6 h of application of a potential of 2 V vs. RHE. Consequently the Au modification has to be replaced by either another precious metal or a corrosion resistant electro-ceramic. The coating reported herein could have a large impact on the cost of PEM electrolyzers for large scale electricity storage from renewables.
La2NiO4 Ceramic Electrodes for Hydrogen Peroxide Electroreduction
Authors: Santos Diogo M.F. , Sousa Nuno , Sljukic Biljana , Sequeira Cesar A.C. , Figueiredo Filipe M
Published: September 2014

Direct borohydride/peroxide fuel cells (DBPFCs) use sodium borohydride (NaBH4) as an anodic fuel and hydrogen peroxide (H2O2) as the oxidant. Currently, we are focused on finding low-cost, stable, durable, and efficient electrocatalytic materials for H2O2 reduction in DBPFCs. Recently, some perovskite-type oxides were found to have reasonable activity for H2O2 electroreduction. Here, La2NiO4 ceramic disks are prepared by mechanosynthesis and characterized by scanning electron microscopy and X-ray diffraction. Cyclic voltammetry, chronoamperometry and chronopotentiometry are used to investigate La2NiO4 activity for H2O2 reduction in alkaline media, and its possible use as cathodes for DBPFCs.
(Invited) Unraveling the Oxygen Reduction Reaction Mechanism and Activity of d-Band Perovskite Electrocatalysts for Low Temperature Alkaline Fuel Cells
Authors: Fabbri Emiliana , Mohamed Rhiyaad , Levecque Pieter , Conrad Olaf , Kötz Ruediger , Schmidt Thomas J.
Published: September 2014

Oxides with a perovskite structure have been recognized as potential catalysts for application in low temperature alkaline fuel cells. Although perovskites have been investigated for several decades as electrocatalysts for the oxygen reduction reaction (ORR), only recently improvements in the ORR activity have been reported, when perovskites are combined with various carbons. This contribution shows the enhancement in the ORR activity when Ba0.5Sr0.5Co0.8Fe0.2O3-δ is coupled with acid treated carbon black. Different mechanisms can account for the improved ORR activity of the composite cathode compared to the single catalyst. Perovskite surface utilization enhancement and synergistic ORR pathways will be discussed in this contribution.
Effect of Au and Ru in Au@Pd and Ru@Pd Core@Shell Nanoparticles for Direct Formic Acid Fuel Cells
Authors: Hu Shuozhen , Scudiero Louis , Ha Su
Published: September 2014

In this research, the effect of Au and Ru in Au@Pd and Ru@Pd on the electronic perturbation and the formic acid oxidation activity is investigated. Au@Pd/C and Ru@Pd/C core@shell nanoparticles with 2 nm Pd shell are synthesized via a two-step process. The electronic perturbation and electrochemical activity of the nanoparticles are tested through X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) measurements, respectively. A positive 0.15 eV binding energy shift for Pd 3p3/2 relative to that of Pd/C is observed for Au@Pd/C nanoparticles suggesting that there is charge transfer from Pd to Au. In addition, CV results show that the peak current density of Au@Pd/C, Ru@Pd/C, and Pd/C are 2.1 mA/cm2, 1.5 mA/cm2, and 1.2 mA/cm2, respectively. Thus, Au@Pd/C presents the highest activity towards FAO, indicating that a charge transfer from Pd to Au leads to formic acid oxidation activity enhancement.
Investigation of Nb2O5/Graphene Supported Platinum-Cobalt Nanocomposite as Electrocatalyst for the Alkaline Alcohols Fuel Cells
Authors: Kepeniene Virginija , Vaiciuniene Jurate , Kondrotas Rokas , Pakstas Vidas , Tamasauskaite-Tamasiunaite Loreta , Norkus Eugenijus
Published: September 2014

In this work Nb2O5/graphene supported PtCo catalyst with the Pt:Co molar ratio equal to 1:7 was fabricated by means of the rapid microwave heating method. The transmission electron microscopy (TEM) was used to detect the shape and size of catalyst particles. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was employed to characterize the composition of the synthesized catalysts. The electrocatalytic activity of the prepared catalysts towards the electro-oxidation of ethanol, methanol and ethylene glycol was investigated in an alkaline medium by means of cyclic voltammetry and chrono-techniques. It has been determined that the Nb2O5/graphene supported PtCo catalyst exhibits a higher electrocatalytic activity with respect to the electro-oxidation of all alcohols as compared to that at the commercial Pt/C catalyst.
(Invited) A Stability Study of Alkali Doped PBI Membranes for Alkaline Electrolyzer Cells
Authors: Jensen Jens Oluf , Aili David , Hansen Martin Kalmar , Li Qingfeng , Bjerrum Niels Janniksen , Christensen Erik
Published: September 2014

Polybenzimidazole membranes in a linear, a crosslinked and a thermally cured form were subjected to aging in 6 M aqueous KOH at 85 ºC for periods of up to 176 days. The aged membranes were characterized with respect to weight loss, mechanical properties and ionic conductivity. The area specific conductivity was similar to a commercial Zirfon membrane and suitable for a water electrolyzer. Some chemical degradation was seen during the aging period, but the crosslinked and the cured materials were both integral after 176 days of aging. A simplified electrolyzer test cell was operated successfully.
(Invited) Thin Robust Anion Exchange Membranes for Fuel Cell Applications
Authors: Sarode Himanshu N , Vandiver Melissa A , Liu Ye , Maes Ashley , Pandey Tara Prasad , Ertem S Piril , Tsai Tsunghan , Zhang Bingzi , Herbst Daniel , Linberg Gerrick , Tse Ying-Lung Steve , Seifert Sönke , Di Noto Vito , Coughlin E. Bryan , Yan Yushan , Voth Gregory , Witten Thomas , Knauss Daniel M , Liberatore Matthew W , Herring Andrew M
Published: September 2014

Extensive transport and modeling studies have been performed on a series of polymers based on the benzyltrimethylamonium cations. We have created a realistic reactive model of solvated hydroxide that has interesting properties in the polymer matrix. In ordered di-block polymers we have strong theoretical evidence for a heterogeneous distribution of water across the channel. Fluoride is used as a non-reactive surrogate for hydroxide to increase the computational efficiency of transport calculations that can be performed. In addition to these studies we are discovering new base stable processable robust polymer backbones and cations. These bulky cations seem to dramatically affect the transport properties of the anions showing a VTF rather than an Arrhenius behavior with temperature.
Insight on Pure vs Air Exposed Hydroxide Ion Conductivity in an Anion Exchange Membrane for Fuel Cell Applications
Authors: Pandey Tara Prasad , Peters Bethanne D. , Liberatore Matthew W , Herring Andrew M
Published: September 2014

Conductivity of pure (air controlled) and air exposed hydroxide ion was compared using a unique sample preparation and conductivity measurements at controlled environment for a commercial FumasepÒ FAA anion exchange membrane. At 95%RH and 80°C, the membrane had conductivity value of 0.075 S/cm at the pure hydroxide form but reduced merely to 0.017 S/cm when the membrane was exposed to ambient CO2 for 2 days. A comparative anionic (OH-, CO3
2-, and HCO3
- forms) conductivity study showed the reduced ionic conductivity value by ¼ of its pure form; closed to HCO3
- forms of the membrane. This indicated the formation of ionic mixture of CO3
2-, HCO3,
- and residual OH- ions in the hydroxide form of the membrane when exposed to air. The hydroxide ions also showed a smaller ionic energy of activation when compared to other anions indicating a smaller ionic transport energy barrier.
Cross-Linked Anion Exchange Membranes for AEMFC
Authors: Amel Alina , Hickner Michael , Ein Eli Yair
Published: September 2014

The effect of cross-linker and its apparent impact on AEM properties will be the focus of this study. Two different cross-linkers were chosen, one has an amino-ether group and the other, has a trymethylhexadecyl amine group. These two cross-linkers have a fundamental difference, where the amino-ether is more hydrophilic and therefore would improve membrane's conductivity and may prevent membrane’s drying out. The properties and the chemical stability of the membrane with these two cross-linkers were investigated. Swelling measurements were examined at various temperatures for both types of samples. Indeed, water uptake were found to be higher for the amino-ether cross-linker. However, degradation measurements analyzed by Elemental Analysis, indicated that the membrane cross-linked by amino-ether group degraded faster at high temperature and pH conditions. Thus, the ether linkage in the cross-linker has a negative influence on the thermal and alkaline stability of the membrane.
Theoretical Study of the Morphologic and Structural Characteristics of an Anion Exchange Membrane Used in AEMFC Using DFT
Authors: Castañeda Ramírez Sergio , Ribadeneira Paz Rafael Esteban
Published: September 2014

Simulations by means of DFT were carried out to represent the structure and morphology of a segment of the anion exchange membrane QSEBS. For three considered structures: tetramethylammonium hydroxide, benzyltrimetylammonium hydroxide and the QSEBS segment, information about spatial distribution, bond distances and total energy was obtained and corroborated with the theoretical study about the degradation of tetramethylammonium hydroxide of reference [1] and the experimental work about the QSEBS membrane of reference [2]. It was found that the obtained structures were in agreement with what is reported in the mentioned studies and what was physically expected.
(Invited) Ionic Liquids, Superionic Glasses, Quasi-Ionic Liquids, Quasi-Liquid Ionics, All with High Conductivities but Some with Little Fluidity. Where does the Paradigm End?
Authors: Angell C Austen
Published: September 2014

We overview the field of ionic liquids from the viewpoint of the electrochemist, considering the different classes of ionic liquids, aprotic, and protic that may be produced within the fields of inorganic and organic chemistry, utilizing both aprotic and protic types and some variants on the theme of particle transfer production of ionic materials. Brief mention will be made of the possible advantages of systems that are semi-liquid, ,being crystal with respect to their centers of mass, having their rotational degrees of freedom, fully excited. Some applications in battery technology will be discussed, and some limitations will be noted.
Lithium Based Ionogel as Solid State Electrolyte: Dynamics of Confined Ionic Liquid, a Neutron Diffusion Study
Authors: Cerclier Carole , Zanotti Jean-Marc , Embs Jan , Le Bideau Jean
Published: September 2014

Obtaining solid-state electrolytes with good electrochemical performances remain challenging. Ionogels, i.e. solid host network confining an ionic liquid, are promising as they keep the macroscopic properties of the confined liquid. However, confinement of an ionic liquid can imply important changes in its molecular dynamics, depending on the route of synthesis and on the confining network. We studied this effect on an imidazolium based ionic liquid with its Lithium salt confined in a biopolymer-silica matrix. Dynamics of bulk and confined solution was probed by quasi-elastic neutron scattering (QENS). The scattering function was modeled successfully with two Lorentzian functions in both cases and revealed a weakly slowed dynamics of imidazolium-based ionic liquid inside the polymer-silica host network.
(3-Aminopropyl)triethoxysilane as a Model Silylamine Reversible Ionic Liquid Used as a Reversible Electrolyte
Authors: Biddinger Elizabeth J. , Jimenez Juan D
Published: September 2014

Separation of the electrochemical product from an electrolyte can add challenges to the overall process. Use of a switchable electrolyte offers the possibility to reduce or eliminate these separation challenges while maintaining high conductivity. Reversible ionic liquids (RevILs) are a type of switchable solvent that could be used as a switchable electrolyte. Switchable solvents are solvents that can have dramatic step-changes in their properties with the introduction of an external stimulus. RevIL systems can be switched from a molecular liquid state to an ionic liquid (IL)-like state. (3-aminopropyl)triethoxysilane (TEtoxySA) has been investigated as a reversible electrolyte. When in the pure RevIL state, the conductivity is prohibitively low to be used as a combined solvent and electrolyte, but in the presence of methanol the conductivity increases by three orders of magnitude. The impact of methanol content, degree of conversion to RevIL and viscosity are shown here.
Ionic Liquid Structure in Thin Films
Authors: Anaredy Radhika S , Lucio Anthony J , Shaw Scott K
Published: September 2014

Room Temperature Ionic liquids present an exciting opportunity to examine surface confined thin fluid films and extended interfacial systems that may prove useful for electrochemical applications. This work explores the behavior of thin (1-5000 nm) films and bulk RTIL interfaces in contact with air and silver metal surfaces. Thin films are introduced by a highly controlled dynamic wetting process. Bulk interfaces are prepared by immersing the metal electrode into an IL solution. Data from ellipsometry, vibrational spectroscopy, contact angle, and electrochemical measurements are reported for a series of Cn-3-methylimidazolium based liquids with varying length alkane tails. Results correlate chemical nature of the liquid and substrates with resulting molecular structure of the interface and behavior of the wetting film. Descriptors include chemical interactions i.e. hydrophobic forces, hydrogen bonding, van der Waals, electrostatics, etc.
Density and Molar Volume of KF-NaF-AlF3 Melts with Al2O3 and CaF2 Additions
Authors: Dedyukhin Alexander , Kataev Alexander , Redkin Alexander , Zaikov Yurii
Published: September 2014

The density of low melting cryolite melts based on the KF-NaF-AlF3 system was studied by the Archimedean technique at temperatures in the 920-1150 K range. The effect of temperature, cryolite ratio (1.3 and 1.5), alumina and calcium fluoride additions was investigated. The density was determined to decrease with the cryolite ratio rise and to increase with the calcium fluoride additions. The alumina additions up to 6 mol.% proved insignificant to affect the density of the melts studied. The molar volume change for the KF-NaF-AlF3 melts was calculated and deduced depending on the temperature, cryolite ratio, alumina and calcium fluoride additions.
Comparison of Some Structural Parameters of the Model Systems nM+[CrX6]3- and 3M+[CrX6]3- + 18MCl (M–Na, K, Cs; X–F, Cl; n=1–6)
Authors: Kuznetsov Sergey A. , Kremenetsky Vyacheslav G.
Published: September 2014

To verify conclusions obtained for the (M+)
n
∙[CrX6] model systems (type I), where M = Na, K, Cs; X- F, Cl, computations of the interaction energy of fragments with various compositions have been carried out in extended model systems (type II), which contain additional 18MX. It has been found that in systems II the composition of the second coordination sphere of the most stable fragments or coincides with the outer-sphere composition of the most stable particles in systems I, or contains one more cation. Both types of systems are used in quantum-chemical modeling of the charge transfer processes.
Corrosion of Corrosion-Resistant and High-Temperature Nickel-Based Alloys in Chloroaluminate Melts
Authors: Abramov Aleksandr V. , Karpov Vyacheslav V. , Zhilyakov Arkadiy Yu. , Gibadullina Alfiya F. , Polovov Ilya B. , Volkovich Vladimir A. , Belikov Sergey V. , Shak Andrey V. , Rebrin Oleg I.
Published: September 2014

The corrosion resistance of Haynes 230, Hastelloy S and X high-temperature alloys and Hastelloy N, B-3, G-35, C-2000 corrosion-resistant alloys was investigated in a wide temperature range (450–650 °C) in fused KCl-AlCl3 mixtures. It was found that the mechanisms of corrosion of high-temperature alloys and corrosion-resistant alloys in KCl-AlCl3 based melts are different. At a critical temperature phase structure of the high-temperature alloys changes after contact with chloroaluminate melts resulting in formation of intermetallic or carbon-containing phases along the grain boundaries that result in increasing strength of the alloys but initiate intense intergranular corrosion. The structural changes in most of the corrosion-resistant alloys take place at higher temperatures but they also can cause structural changes in the materials. It was shown that both types of alloys undergo intergranular corrosion up to the critical conditions. Formation of different secondary phases was detected and their influence on the corrosion processes mechanism is analyzed.
Lanthanum Activity, Activity Coefficients and Solubility in Gallium-Indium Liquid Alloys
Authors: Dedyukhin Alexander S. , Shchetinskiy Andrey V. , Volkovich Vladimir A. , Yamshchikov Leonid F. , Osipenko Alexandr G.
Published: September 2014

Solubility of lanthanum was determined in gallium-indium alloys of various compositions (21.4, 40 and 70 wt.% In) between 298-1081 K employing sedimentation technique. Lanthanum activity was determined in the same alloys using electromotive force measurements method at 573-1075 K and activity coefficients calculated from the difference of activity and solubility.
Thermodynamic Analysis of Solutions of Oxides in the Alkali Melts
Authors: Skryptun Igor N
Published: September 2014

This study investigates the isothermal saturation solubility of metal oxide in alkali and alkaline-salt melts in the temperature range 673 – 873 K. The effect of temperature on the metal oxide solubility in alkali melts are satisfactorily described by the equation of the straight line lnC = A + BT
–1, where C is concentration (mole fraction) of oxide in melts, and A and B are constants. The thermodynamic analysis of solutions of metal oxides in molten alkalis was carried out.
Electrochemical Behavior of Ti in Molten Fluoride-Oxide System
Authors: Yamanaka Yuka , Morishige Taiki , Takenaka Toshihide
Published: September 2014

The cathodic reaction of Ti has been studied in a CaF2-MgF2 bath with CaO and TiO2 at 1373K. Cyclic voltammograms were measured in the baths of various compositions, and the dependence of the cathodic reaction of Ti on the bath composition was discussed. With reference to the results of the cyclic voltammetry, Ti metal deposition by potentio-static electrolysis was attempted. It was shown that the reduction sequence of Ti consisted of three steps, and Ti metal was deposited under the suitable condition. The cathodic behavior of Ti was influenced by the molar ratio of TiO2 to CaO in the melt. Considering the previous results of Ti electrolysis by using DC-ESR unit, it is strongly suggested that a binuclear complex ion of Ti with O, such as Ti2O7
6-, affects the reduction sequence of Ti in CaF2-CaO-TiO2 and CaF2-MgF2-CaO-TiO2 baths.
(Invited) Electrodeposition of Liquid Metals from Molten Salts
Authors: Haarberg Geir Martin
Published: September 2014

Many important metals are being produced by electrolysis in molten salts (aluminium, sodium, rare earths and other reactive metals). Also industrial electrorefining of aluminium takes place in a molten salt electrolyte. Current efficiency for metal deposition, specific energy consumption and environmental issues are important topics for considering the success of such processes. A wide range of electrolytes including molten salts can be used to electrowin reactive metals. New electrochemical processes are proposed for recycling of metals in molten salts. Controlled laboratory experiments were carried out to study electrolytic deposition of the liquid metals aluminium, magnesium, lead, iron and titanium alloys from molten salt electrolytes. An important feature is the fact that metals are soluble in molten salts. The excess electrons associated with the dissolved metal are in some cases responsible for the presence of electronic conduction in mixtures of molten salts and dissolved metals. In other cases the metal dissolves under the formation of a subvalent species. Diffusion and charge transfer kinetics related to metal deposition processes in molten salts were studied by using electrochemical techniques.
Electrodeposition of Mg-Ni-Al Alloy in Low Temperature Molten Salts
Authors: Xu Junli , Zhang Xia , Shi Zhongning , Haarberg Geir Martin
Published: September 2014

Mg-Ni-Al alloys were prepared in urea-acetamide-NaBr low temperature molten salts by electrodeposition method. Effects of electrodeposition parameters such as deposition temperature and time on the composition and microstructure of deposits were investigated. The results show that the content of Mg decreases with the increase of deposition temperature, while it increases first, and then decreases with prolonged deposition time. XRD results indicate that the deposits are composed of Mg-Cu, Mg-Al-Cu metallic compounds and Mg-Ni oxides.
Effects of Process Conditions on the Fluidised Cathode Electrochemical Reduction of Tungsten Oxide in Molten LiCl-KCl Eutectic
Authors: Abdulaziz Rema , Brown Leon D , Inman Douglas , Simons Stefaan J. R. , Shearing Paul R , Brett Dan J. L.
Published: September 2014

The electrochemical reduction of metal oxides is important in the production of refractory metals. Conventional electroreduction routes have limitations related to oxide build-up near the surface of solid precursors, as well as operative electrolyte access to the inner parts of the precursors. The fluidised cathode process offers a promising substitute. The process is demonstrated on a WO3 and LiCl-KCl model system. Cyclicvoltammetry and chronoamperometry were used to investigate the process. Process conditions such as fluidisation rate and concentration of particles in the melt, and their effects, are investigated.
Molten Salt Assisted Electrochemical Separation of Spent Fuel Surrogates by Partial Direct Reduction and Selective Anodic Dissolution
Authors: Stevenson Anthony , Hu Di , Chen George Zheng
Published: September 2014

Pyrometallurgical reprocessing of spent nuclear fuels has experienced growing interest in recent years as it presents a desirable and proliferation resistant separation process capable of significantly reducing volumes of high level waste (HLW). Additionally, the use of molten salts in pyro-reprocessing is seen as forward compatible with the new GEN IV fast neutron nuclear reactors. In this work, the ability to selectively partition spent fuel surrogate species in solid phase by molten salt electrochemistry was assessed in a proof of concept experiment by the use of the 2NiO-CeO2 binary. In a three electrode cell using potentiostatic electrolysis it was found that close to 80% of the Ni presence in the surface of the precursor was removed following a partial direct reduction of NiO by the FFC Cambridge Process, followed by anodic dissolution to remove the metallic Ni phase. The mixture of more analogous electrochemical surrogates ZrO2 and CeO2 to that of UO2 and PuO2 were then assessed to further confirm the application of this novel recycling technology.
Electrochemical Properties of Molybdenum in Alkali Chloride Melts
Authors: Ivanov Alexander B. , Volkovich Vladimir A. , Likhachev Pavel Yu. , Kamalov Robert V.
Published: September 2014

Behavior of molybdenum was studied in individual fused alkali chlorides and their mixtures employing electrochemical and spectroscopic techniques. Formal standard electrode potentials of molybdenum and thermodynamics of molybdenum chloride were obtained in molten LiCl, NaCl, KCl, RbCl, CsCl at 1123 K, NaCl-CsCl eutectic at 793-1023 K, NaCl-KCl equimolar mixture at 973-1123 K, LiCl-KCl-CsCl eutectic at 633-1173 K. Diffusion coefficients of molybdenum ions were determined in LiCl-KCl-CsCl eutectic melt. Electronic absorption spectra of Mo(III) ions were measured in individual salts and their mixtures and spectroscopic parameters of MoCl6
3- complex ions determined.
(Invited) Cellulose-Chitosan-Keratin Composite Materials: Synthesis, Immunological and Antibacterial Properties
Authors: Rosewald Meghann , Hou Fang Yao Stephen , Mututuvari Tamutsiwa m , Harkins April , Tran Chieu d
Published: September 2014

Novel composites were synthesized from keratin (KER), cellulose (CEL) and chitosan (CS). The method is recyclable because majority (>88%) of [BMIm+Cl-], an ionic liquid (IL), used as the sole solvent, was recovered for reuse. Experimentally, it was confirmed that unique properties of each component remain intact in the composites, namely bactericide (from KER and CS) and anti-inflammatory property (from KER). Specifically, the composites were examined for their anti-inflammatory influence on macrophages. The cells were imaged and immunophenotyped to determine the quantity using the macrophage marker CD11b. The 75:25 [KER+CS] composite was found to have the least amount of CD11b macrophages compared to other composites. Bactericidal assays indicated that all composites, except the 25:75 [KER+CS], substantially reduce the growth of organisms such as vancomycin resistant Enterococcus (VRE) and Eschericia coli. The results clearly indicate that the composites possess all properties needed for effective use as a wound dressing
Laser Induced Natural Fiber Welding of Cellulosic Substrates
Authors: Brown E. Kathryn , Dennis Kathleen , Haverhals Luke M. , Sweely Kurt D. , De Long Hugh C. , Trulove Paul C.
Published: September 2014

Laser assisted heating of an ionic liquid (IL), 1-ethyl-3-methyl-imidazolium acetate (EMIAc), coated cotton paper substrate was used to effect natural fiber welding (NFW). By using a programmable commercial CO2 laser cutter with controllable parameters such as laser power and number of passes and tight control over IL solution composition and concentration (water content), spatially specific laser welding with a resolution of approximately 175 µm was achieved. Treated cotton papers were investigated through tensile testing, scanning electron microscopy (SEM), attenuated total reflectance infrared spectroscopy (ATR-IR), and confocal fluorescence microscopy (CFM).
Natural Fiber Welded Composite Yarns
Authors: Brown E. Kathryn , Durkin David P. , Fox Eric T. , Haverhals Luke M. , Sweely Kurt D. , De Long Hugh C. , Trulove Paul C.
Published: September 2014

In this work, all-natural textile composites were prepared from commercially available linen yarns and chitin. An ionic liquid (IL), 1-ethyl-3-methyl-imidazolium acetate, was used to dissolve chitin, a natural biopolymer found in the exoskeletons of crustaceans and insects. Chitin was incorporated into linen yarns via IL assisted natural fiber welding (NFW). These biocomposites have the advantage of maintaining the structural integrity of the underlying yarn while incorporating a functional biopolymer, chitin on the surface and within the structure. Composite materials were evaluated for chitin integration through tensile testing, scanning electron microscopy (SEM), and confocal fluorescence microscopy (CFM).
Electrochemical Synthesis of NiSi2 from a NaCl-NaF-K2SiF6 Melt on a Ni Cathode
Authors: Kochetova Svetlana Anatolevna , Pisanenko Alexandr Dmitrievich , Devyatkin Sergei Vladimirovich
Published: September 2014

The aim of this work was to examine the possibility of producing nickel silicides by the electrolysis of molten salts, containing silicon ions, on a nickel cathode. Possibility of electrodeposition of nickel disilicide from molten salts was investigated by thermodynamic calculation, voltametric investigation and electrolysis experiments. The electrochemical behavior of the NaCl–NaF–K2SiF6 molten salts system was studied by cyclic voltammetry. The electrolysis was carried out in a NaCl–NaF–K2SiF6 melt in a glassy carbon crucible at 7200C in argon atmosphere; a nickel plate was used as the cathode. Cathode products were analyzed by X-ray and JEM-2100F SEM. Coatings of nickel disilicide were deposited from NaCl-NaF-K2SiF6 melts on a Ni cathode at 7200C in argon atmosphere.
Carbon Fibers and Nanotubes as a Product of Interaction between Silicon Carbide and Carbonate Melt
Authors: Devyatkin Sergei Vladimirovich
Published: September 2014

In this work, the interaction of Si, SiC and TiC with a Na2CO3-K2CO3 melt at 7500С on Ar atmosphere and in air was investigated. The optimal process for the fabrication of carbon fibers or nanotubes is interaction between silicon carbide and carbonate melts. It has been show that the modification of carbon materials depends on SiC powder fineness.
Corrosion Resistance of Aluminum Films Electroplated on Steel from Chloroaluminate Ionic Liquids Containing Toluene as a Co-Solvent
Authors: Chou Li-Hsien , Hussey Charles L.
Published: September 2014

Dense and adhesive pure aluminum layers were electroplated on Cu and mild carbon steel plates from the Lewis acidic aluminum chloride-1-ethyl-3-methylimidazolium chloride [60 mole percent (m/o) AlCl3] ionic liquid by using current-controlled DC methods. The influence of the current density on the surface morphology and grain size of the electrodeposited Al was investigated by optical microscopy. The corrosion resistance of Al-coated steel was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements for deposits prepared with and without toluene as a co-solvent. Both deposition current density and deposit thickness were crucial factors affecting the structure, integrity, and corrosion resistance of electrodeposited Al layers on steel substrates. Aluminum films prepared in the ionic liquid containing toluene exhibited better overall durability, brightness, and practical corrosion resistance than films prepared from the neat ionic liquid.
Electrodeposition of Al-W-Mn Alloy from Lewis Acidic AlCl3−1-Ethyl-3-Methylimidazolium Chloride Ionic Liquid
Authors: Tsuda Tetsuya , Ikeda Yuichi , Kuwabata Susumu , Stafford Gery R. , Hussey Charles L.
Published: September 2014

The electrodeposition of non-equilibrium ternary Al-W-Mn alloys was investigated in the Lewis acidic 66.7-33.3 mol % aluminum chloride–1-ethyl-3-methylimidazolium chloride (AlCl3–[C2mim]Cl) ionic liquid (IL) with K3[W2Cl9] and MnCl2 to improve the properties of binary Al-W alloy electrodeposits. The Al-W-Mn alloys were electrochemically deposited on Cu substrates. The W content in the Al-W-Mn alloys monotonically decreased with increasing the applied current density independently of the K3[W2Cl9] and MnCl2 concentration in the IL solution. The Mn content in the ternary alloys was significantly affected by the electrodeposition condition. The XRD and EDS analyses revealed that the Al-W-Mn alloys prepared in this research have non-equilibrium solid solution and amorphous phases without chloride contamination. The surface morphology was improved by adding Mn to the Al-W alloy, and the pitting potential of the Al-W-Mn alloy surpassed that for the electrodeposited Al-W and Al-Mn binary alloy systems.
An Electrochemical and Spectroelectrochemical Study of Ln(II) (Ln = Sm, Eu, Yb) Species in NaCl-2CsCl Melt
Authors: Volkovich Vladimir A. , Ivanov Alexander B. , Sobolev Alexander A. , Vasin Boris D. , Griffiths Trevor R.
Published: September 2014

The behavior of lanthanide (samarium, europium and ytterbium) chloride species in NaCl-2CsCl eutectic based melts was studied between 823–1023 K employing cyclic voltammetry, high temperature electronic absorption spectroscopy and spectroelectrochemistry. Diffusion coefficients of the lanthanide chloro-species, formal standard red-ox potentials and thermodynamics of the formation of LnCl3 from the corresponding dichlorides in the melts were determined. A series of spectroelectrochemical experiments was performed to study cathodic reduction of Ln(III) ions under potentiostatic conditions. Sm(III), Eu(III) and Yb(III) species in NaCl-2CsCl melts can be reduced by metallic zirconium and this reaction was investigated using high temperature spectroscopy.
Charge and Mass Transfer on a La2O3 Added Li/Na or Li/K Molten Carbonate Meniscus Electrode of LaNiO3 Coated Au Ring for Oxygen Reduction Reaction
Authors: Takeuchi Yuki , Matsuzawa Koichi , Kohno Yuji , Mitsushima Shigenori
Published: September 2014

LaNiO3 is an alternative cathode material of NiO for molten carbonate fuel cells (MCFCs) because of extremely higher stability than NiO in La saturated molten carbonates. In this study, the charge transfer on LaNiO3 and mass transfer resistance through La saturated molten carbonates for the ORR have been evaluated by the combination of a potential step method and steady state method on a meniscus electrode to discuss the ORR activity and mechanism of the LaNiO3 in Li/Na and Li/K carbonate eutectic with saturated La. The activity of ORR on LaNiO3
electrode was not less than that on NiO electrode and the rate-determination step would be competition of peroxide (POP) and percarbonate path (PCP) at meniscus state, and mass transfer resistance controlled over all reaction rate for steady state. In addition, Li/K system had higher ORR rate than Li/Na system because of large solubility of O2 under ambient pressure.
Fracture Dynamics during the Silicon Layer Transfer of the Smart Cut™ Process
Authors: Massy Damien , Mazen Frédéric , Ragani Jennifer , Madeira Florence , Landru Didier , Rieutord François
Published: September 2014

Fracture crack propagation involved in silicon layer transfer of the Smart Cut™ process is experimentally studied. Measurements of both crack propagation velocity and crack opening displacement are performed at different temperatures using a specially designed optical setup. After a quick acceleration, the fracture velocity is found to be constant along the sample, with values in the km.s-1 range. The crack deformation profile is shown to be oscillatory, with typical wavelength in the centimeter range. The increase of temperature leads to higher crack velocities and gap openings due to an increase of the gas pressure inside microcracks. The maximum air gap thickness increases linearly with the splitting temperature, as expected for an ideal gas expansion.
Room-Temperature Wafer Direct Bonding Using Ne-Beam Surface-Activation
Authors: Takagi Hideki , Kurashima Yuichi , Maeda Atsuhiko
Published: September 2014

In the surface activated bonding (SAB) at room temperature, the surfaces of wafers are sputter etched by high-energy ion/atom beams of inert gases to remove surface contaminants and create active surfaces, which are ready to form inter-atomic bonds even at room temperature. For the purpose Ar has been used. However, sputter etching by Ar high-energy ion/atom beam causes increase of surface roughness. We have examined the applicability of fast-atom-beam (FAB) of Ne and Xe to SAB of Si wafers at room temperature. We confirmed that Ne-FAB does not cause surface roughening and Si wafers are successfully bonded by Ne-beam surface activation. In addition, we found that Ne-FAB sputter etching has surface smoothing effect which can improve various properties of the bonding interface.
Combined Surface-Activated Bonding (SAB) Technologies for New Approach to Low Temperature Wafer Bonding
Authors: He Ran , Fujino Masahisa , Yamauchi Akira , Suga Tadatomo
Published: September 2014

Wafer surface activation is of great importance for low temperature wafer bonding process development. However, different surface activation methods are needed for various bonding materials due to their different requirements and mechanisms for low temperature bonding. A challenge of the low temperature wafer bonding technology is to develop compatible surface activation processes for hybrid surfaces (e.g., Cu/polymer adhesive and Cu/SiO2 hybrid surfaces). In this study, we developed surface activation processes for low temperature Cu/dielectric hybrid bonding. We report the results of surface treatment for Cu/adhesive hybrid surface by using Ar plasma and Ar fast atom bombardment, and a combined SAB process for SiO2 hydrophilic bonding. Post-bonding vacuum annealing is employed to develop void-free hydrophilic SiO2 wafer bonding.
Enhancement of Bonding Strength for Low Temperature Si3N4/Si3N4 Direct Wafer Bonding by Nitrogen-Plasma Activation and Hydrofluoric Pre-dip
Authors: Lo F. -S. , Chiang C. -C. , Li C. , Lee T. -H.
Published: September 2014

Prior to exposing to plasma for surface activation, dipping the silicon nitride (Si3N4) surfaces on one pair of silicon wafers in diluted hydrofluoric (HF) solution is for the sake of low temperature wafer bonding. We found the bonding strength (2,500 mJ/m2) reaches the level of silicon fracture through a 200°C annealing less than 24 hours compared with 400 hours done by HF-dip merely. We suggest the bonding mechanism as following: the HF-dip treatment passivated the Si dangling Si bonds on the broken Si-N network of the Si3N4 surface to form sufficient high density of Si-H bonds. And then the application of N2 plasma treatment can increase the density of Si-H-N bonds for forming hydrogen bonds between the two mating surfaces to bridge the two bonding surfaces resulting in high bonding strength after annealing.