WorldWideScience

Sample records for anodes

  1. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  2. FLUORINE CELL ANODE ASSEMBLY

    Science.gov (United States)

    Cable, R.E.; Goode, W.B. Jr.; Henderson, W.K.; Montillon, G.H.

    1962-06-26

    An improved anode assembly is deslgned for use in electrolytlc cells ln the productlon of hydrogen and fluorlne from a moIten electrolyte. The anode assembly comprises a copper post, a copper hanger supported by the post, a plurality of carbon anode members, and bolt means for clamplng half of the anode members to one slde of the hanger and for clamplng the other half of the anode members to the other slde of the hanger. The heads of the clamplng bolts are recessed withln the anode members and carbon plugs are inserted ln the recesses above the bolt heads to protect the boIts agalnst corroslon. A copper washer is provided under the head of each clamplng boIt such that the anode members can be tightly clamped to the hanger with a resultant low anode jolnt resistance. (AEC)

  3. Anodized dental implant surface

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Mishra

    2017-01-01

    Full Text Available Purpose: Anodized implants with moderately rough surface were introduced around 2000. Whether these implants enhanced biologic effect to improve the environment for better osseointegration was unclear. The purpose of this article was to review the literature available on anodized surface in terms of their clinical success rate and bone response in patients till now. Materials and Methods: A broad electronic search of MEDLINE and PubMed databases was performed. A focus was made on peer-reviewed dental journals. Only articles related to anodized implants were included. Both animal and human studies were included. Results: The initial search of articles resulted in 581 articles on anodized implants. The initial screening of titles and abstracts resulted in 112 full-text papers; 40 animal studies, 16 studies on cell adhesion and bacterial adhesion onto anodized surfaced implants, and 47 human studies were included. Nine studies, which do not fulfill the inclusion criteria, were excluded. Conclusions: The long-term studies on anodized surface implants do favor the surface, but in most of the studies, anodized surface is compared with that of machined surface, but not with other surfaces commercially available. Anodized surface in terms of clinical success rate in cases of compromised bone and immediately extracted sockets has shown favorable success.

  4. Anode Support Creep

    DEFF Research Database (Denmark)

    2015-01-01

    Initial reduction temperature of an SOC is kept higher than the highest intended operation temperature of the SOC to keep the electrolyte under compression by the Anode Support at all temperatures equal to and below the maximum intended operation temperature.......Initial reduction temperature of an SOC is kept higher than the highest intended operation temperature of the SOC to keep the electrolyte under compression by the Anode Support at all temperatures equal to and below the maximum intended operation temperature....

  5. Liquid Silicon Pouch Anode

    Science.gov (United States)

    2017-09-06

    collector 18 can be made from nickel; however, other high conductivity metals and alloys can be used for this such as gold, silver , platinum, alloys of...The conductive particles can be carbon such as carbon black or graphite. These particles can also be metals such as copper, nickel, silver , gold...anode cycling characteristics, higher battery capacity, and longer cycle life. [0005] Rechargeable batteries with lithium metal anodes have been

  6. Lithium batteries, anodes, and methods of anode fabrication

    KAUST Repository

    Li, Lain-Jong

    2016-12-29

    Prelithiation of a battery anode carried out using controlled lithium metal vapor deposition. Lithium metal can be avoided in the final battery. This prelithiated electrode is used as potential anode for Li- ion or high energy Li-S battery. The prelithiation of lithium metal onto or into the anode reduces hazardous risk, is cost effective, and improves the overall capacity. The battery containing such an anode exhibits remarkably high specific capacity and a long cycle life with excellent reversibility.

  7. Inert Anode Report

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1999-07-01

    This ASME report provides a broad assessment of open literature and patents that exist in the area of inert anodes and their related cathode systems and cell designs, technologies that are relevant for the advanced smelting of aluminum. The report also discusses the opportunities, barriers, and issues associated with these technologies from a technical, environmental, and economic viewpoint.

  8. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev [Latham, NY

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  9. Movable anode x-ray source with enhanced anode cooling

    Science.gov (United States)

    Bird, C.R.; Rockett, P.D.

    1987-08-04

    An x-ray source is disclosed having a cathode and a disc-shaped anode with a peripheral surface at constant radius from the anode axis opposed to the cathode. The anode has stub axle sections rotatably carried in heat conducting bearing plates which are mounted by thermoelectric coolers to bellows which normally bias the bearing plates to a retracted position spaced from opposing anode side faces. The bellows cooperate with the x-ray source mounting structure for forming closed passages for heat transport fluid. Flow of such fluid under pressure expands the bellows and brings the bearing plates into heat conducting contact with the anode side faces. A worm gear is mounted on a shaft and engages serrations in the anode periphery for rotating the anode when flow of coolant is terminated between x-ray emission events. 5 figs.

  10. Process for anodizing aluminum foil

    International Nuclear Information System (INIS)

    Ball, J.A.; Scott, J.W.

    1984-01-01

    In an integrated process for the anodization of aluminum foil for electrolytic capacitors including the formation of a hydrous oxide layer on the foil prior to anodization and stabilization of the foil in alkaline borax baths during anodization, the foil is electrochemically anodized in an aqueous solution of boric acid and 2 to 50 ppm phosphate having a pH of 4.0 to 6.0. The anodization is interrupted for stabilization by passing the foil through a bath containing the borax solution having a pH of 8.5 to 9.5 and a temperature above 80 0 C. and then reanodizing the foil. The process is useful in anodizing foil to a voltage of up to 760 V

  11. Mesoporous Silicon-Based Anodes

    Science.gov (United States)

    Peramunage, Dharmasena

    2015-01-01

    For high-capacity, high-performance lithium-ion batteries. A new high-capacity anode composite based on mesoporous silicon is being developed. With a structure that resembles a pseudo one-dimensional phase, the active anode material will accommodate significant volume changes expected upon alloying and dealloying with lithium (Li).

  12. Anodic Concentration Polarization in SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Williford, Rick E.; Chick, Lawrence A.; Maupin, Gary D.; Simner, Steve P.; Stevenson, Jeffry W.; Khaleel, Mohammad A.; Wachsman, ED, et al

    2003-08-01

    Concentration polarization is important because it determines the maximum power output of a solid oxide fuel cell (SOFC) at high fuel utilization. Anodic concentration polarization occurs when the demand for reactants exceeds the capacity of the porous ceramic anode to supply them by gas diffusion mechanisms. High tortuosities (bulk diffusion resistances) are often assumed to explain this behavior. However, recent experiments show that anodic concentration polarization originates in the immediate vicinity of the reactive triple phase boundary (TPB) sites near the anode/electrolyte interface. A model is proposed to describe how concentration polarization is controlled by two localized phenomena: competitive adsorption of reactants in areas adjacent to the reactive TPB sites, followed by relatively slow surface diffusion to the reactive sites. Results suggest that future SOFC design improvements should focus on optimization of the reactive area, adsorption, and surface diffusion at the anode/electrolyte interface.

  13. Nano structural anodes for radiation detectors

    Science.gov (United States)

    Cordaro, Joseph V.; Serkiz, Steven M.; McWhorter, Christopher S.; Sexton, Lindsay T.; Retterer, Scott T.

    2015-07-07

    Anodes for proportional radiation counters and a process of making the anodes is provided. The nano-sized anodes when present within an anode array provide: significantly higher detection efficiencies due to the inherently higher electric field, are amenable to miniaturization, have low power requirements, and exhibit a small electromagnetic field signal. The nano-sized anodes with the incorporation of neutron absorbing elements (e.g., .sup.10B) allow the use of neutron detectors that do not use .sup.3He.

  14. Monitoring of epitaxial graphene anodization

    International Nuclear Information System (INIS)

    Vagin, Mikhail Yu.; Sekretaryova, Alina N.; Ivanov, Ivan G.; Håkansson, Anna; Iakimov, Tihomir; Syväjärvi, Mikael; Yakimova, Rositsa; Lundström, Ingemar; Eriksson, Mats

    2017-01-01

    Anodization of a graphene monolayer on silicon carbide was monitored with electrochemical impedance spectroscopy. Structural and functional changes of the material were observed by Raman spectroscopy and voltammetry. A 21 fold increase of the specific capacitance of graphene was observed during the anodization. An electrochemical kinetic study of the Fe(CN) 6 3−/4− redox couple showed a slow irreversible redox process at the pristine graphene, but after anodization the reaction rate increased by several orders of magnitude. On the other hand, the Ru(NH 3 ) 6 3+/2+ redox couple proved to be insensitive to the activation process. The results of the electron transfer kinetics correlate well with capacitance measurements. The Raman mapping results suggest that the increased specific capacitance of the anodized sample is likely due to a substantial increase of electron doping, induced by defect formation, in the monolayer upon anodization. The doping concentration increased from less than 1 × 10 13 of the pristine graphene to 4–8 × 10 13 of the anodized graphene.

  15. Electrically Conductive Anodized Aluminum Surfaces

    Science.gov (United States)

    Nguyen, Trung Hung

    2006-01-01

    Anodized aluminum components can be treated to make them sufficiently electrically conductive to suppress discharges of static electricity. The treatment was conceived as a means of preventing static electric discharges on exterior satin-anodized aluminum (SAA) surfaces of spacecraft without adversely affecting the thermal-control/optical properties of the SAA and without need to apply electrically conductive paints, which eventually peel off in the harsh environment of outer space. The treatment can also be used to impart electrical conductivity to anodized housings of computers, medical electronic instruments, telephoneexchange equipment, and other terrestrial electronic equipment vulnerable to electrostatic discharge. The electrical resistivity of a typical anodized aluminum surface layer lies between 10(exp 11) and 10(exp 13) Omega-cm. To suppress electrostatic discharge, it is necessary to reduce the electrical resistivity significantly - preferably to surface becomes covered and the pores in the surface filled with a transparent, electrically conductive metal oxide nanocomposite. Filling the pores with the nanocomposite reduces the transverse electrical resistivity and, in the original intended outer-space application, the exterior covering portion of the nanocomposite would afford the requisite electrical contact with the outer-space plasma. The electrical resistivity of the nanocomposite can be tailored to a value between 10(exp 7) and 10(exp 12) Omega-cm. Unlike electrically conductive paint, the nanocomposite becomes an integral part of the anodized aluminum substrate, without need for adhesive bonding material and without risk of subsequent peeling. The electrodeposition process is compatible with commercial anodizing production lines. At present, the electronics industry uses expensive, exotic, electrostaticdischarge- suppressing finishes: examples include silver impregnated anodized, black electroless nickel, black chrome, and black copper. In

  16. Anodic oxide films on tungsten

    International Nuclear Information System (INIS)

    Di Paola, A.; Di Quarto, F.; Sunseri, C.

    1980-01-01

    Scanning electron microscopy was used to investigate the morphology of anodic oxide films on tungsten, obtained in various conditions of anodization. Studies were made of the growth of porous films, whose thickness increases with time and depends upon the current density. Temperature and electrolyte composition influence the film morphology. Gravimetric measurements of film dissolution at 70 0 C show that after a transient time, the rate of metal dissolution and that of film formation coincide. The porous films thicken because tungsten dissolves as WO 2 2+ and precipitates as WO 3 .H 2 O. (author)

  17. Anodic selective functionalization of cyclic amine derivatives

    OpenAIRE

    Onomura, Osamu

    2012-01-01

    Anodic reactions are desirable methods from the viewpoint of Green Chemistry, since no toxic oxidants are necessary for the oxidation of organic molecules. This review introduces usefulness of anodic oxidation and successive reaction for selective functionalization of cyclic amine derivatives.

  18. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.

    2004-01-01

    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  19. Ellipsometry of anodic film growth

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.G.

    1978-08-01

    An automated computer interpretation of ellisometer measurements of anodic film growth was developed. Continuous mass and charge balances were used to utilize more fully the time dependence of the ellipsometer data and the current and potential measurements. A multiple-film model was used to characterize the growth of films which proceeds via a dissolution--precipitation mechanism; the model also applies to film growth by adsorption and nucleation mechanisms. The characteristic parameters for film growth describe homogeneous and heterogeneous crystallization rates, film porosities and degree of hydration, and the supersaturation of ionic species in the electrolyte. Additional descriptions which may be chosen are patchwise film formation, nonstoichiometry of the anodic film, and statistical variations in the size and orientation of secondary crystals. Theories were developed to describe the optical effects of these processes. An automatic, self-compensating ellipsometer was used to study the growth in alkaline solution of anodic films on silver, cadmium, and zinc. Mass-transport conditions included stagnant electrolyte and forced convection in a flow channel. Multiple films were needed to characterize the optical properties of these films. Anodic films grew from an electrolyte supersatuated in the solution-phase dissolution product. The degree of supersaturation depended on transport conditions and had a major effect on the structure of the film. Anodic reaction rates were limited by the transport of charge carriers through a primary surface layer. The primary layers on silver, zinc, and cadmium all appeared to be nonstoichiometric, containing excess metal. Diffusion coefficients, transference numbers, and the free energy of adsorption of zinc oxide were derived from ellipsometer measurements. 97 figures, 13 tables, 198 references.

  20. Fabrication of advanced design (grooved) cermet anodes

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.F. Jr. [Pacific Northwest Lab., Richland, WA (United States); Huettig, F.R. [Ceramic Magnetics, Inc., Fairfield, NJ (United States)

    1993-05-01

    Attempts were made to fabricate full-size anodes with advanced, or grooved, design using isostatic pressing, slip casting injection molding. Of the three approaches, isostatic pressing produced an anode with dimensions nearest to the target specifications, without serious macroscopic flaws. This approach is considered the most promising for making advanced anodes for aluminum smelting. However, significant work still remains to optimize the physical properties and microstructure of the anode, both of which were significantly different from that of previous anodes. Injection molding and slip casting yielded anode materials with serious deficiencies, including cracks and holes. Injection molding gave cermet material with the best intrinsic microstructure, i.e., the microstructure of the material between macroscopic flaws was very similar to that of anodes previously made at PNL. Reason for the similarity may have to do with amount of residual binder in the material prior to sintering.

  1. Magnesium sacrificial anode behavior at elevated temperature

    International Nuclear Information System (INIS)

    Othman, Mohsen Othman

    2006-01-01

    Magnesium sacrificial anode coupled to mild steel was tasted in sodium chloride and tap water environments at elevated temperatures. The anode failed to protect the mild steel specimens in tap water environment at all temperatures specified. This was partly due to low conductivity of this medium. The temperature factor did not help to activate the anode in this medium. In sodium chloride environment the anode demonstrated good protection for steel cathodes. The weight loss was high for magnesium in sodium chloride environment particularly beyond 60 degree centigrade. In tap water environment the weight loss was negligible for the anode. It also suffered localized shallow pitting corrosion. Magnesium anode cannot be utilized where high temperature is involved particularly in high conductivity mediums. Protection of structures containing high resistivity waters is not feasible using sacrificial anode system. (author)

  2. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  3. Process and electrolyte for applying barrier layer anodic coatings

    International Nuclear Information System (INIS)

    Dosch, R.G.; Prevender, T.S.

    1975-01-01

    Various metals may be anodized, and preferably barrier anodized, by anodizing the metal in an electrolyte comprising quaternary ammonium compound having a complex metal anion in a solvent containing water and a polar, water soluble organic material. (U.S.)

  4. Multi-anode wire straw tube tracker

    International Nuclear Information System (INIS)

    Oh, S.H.; Ebenstein, W.L.; Wang, C.W.

    2011-01-01

    We report on a test of a straw tube detector design having several anode (sense) wires inside a straw tube. The anode wires form a circle inside the tube and are read out independently. This design could solve several shortcomings of the traditional single wire straw tube design such as double hit capability and stereo configuration.

  5. Screened anode N/sub 2/ laser

    Energy Technology Data Exchange (ETDEWEB)

    Sabry, M.M.F.

    1985-01-01

    An experimental study of the effect of screening the discharge channel on the output energy is presented. It has been found that a screened anode nitrogen laser generates higher output energy than that of a screened cathode, and also higher than that when both cathode and anode are unshielded at higher pressures.

  6. Ultrasound-assisted anodization of aluminum in oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Rong; Jiang Kaiming [Department of Physics, Shanghai Maritime University, 1550 Pudong Avenue, Shanghai 200135 (China); Zhu Yun [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Qi Haiyang [Department of Physics, Shanghai Maritime University, 1550 Pudong Avenue, Shanghai 200135 (China); Ding Guqiao, E-mail: gqding@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China)

    2011-10-15

    Porous anodic alumina is an important nanoscale template for fabrication of various nanostructures. We report a new ultrasound-assisted anodization process in oxalic acid. Under the continuous irradiation of ultrasound, the one-step-anodized sample has a smooth and clean surface, and two-step-anodization brings ordered porous anodic alumina with higher growth rate of 52 {mu}m/h. The ultrasound applied during the anodization can clean the surface and enhance the nanopore growth since it can accelerate the oxide dissolving on the electrolyte/oxide interface. The ultrasound-assisted anodization may be utilized for other anodizations.

  7. Discharge modes at the anode of a vacuum arc

    International Nuclear Information System (INIS)

    Miller, H.C.

    1982-01-01

    The two most common anode modes in a vacuum arc are the low current mode, where the anode is basically inert; and the high current mode with a fully developed anode spot. This anode spot is very bright, has a temperature near the boiling point of the anode material, and is a copious source of vapor and energetic ions. However, other anode modes can exist. A low current vacuum arc with electrodes of readily sputterable material will emit a flux of sputtered atoms from the anode. An intermediate currents an anode footpoint can form. This footpoint is luminous, but much cooler than a true anode spot. Finally, a high current mode can exist where several small anode spots are present instead of a single large anode spot

  8. Perovskites synthesis to SOFC anodes

    International Nuclear Information System (INIS)

    Wendler, L.P.; Chinelatto, A.L.; Chinelatto, A.S.A.; Ramos, K.

    2012-01-01

    Perovskite structure materials containing lanthanum have been widely applied as solid oxide fuel cells (SOFCs) electrodes, due to its electrical properties. Was investigated the obtain of the perovskite structure LaCr 0,5 Ni 0,5 O 3 , by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300 deg C, 600 deg C, 700 deg C and 850 deg C. The resulting powders were characterized by X-ray diffraction to determine the existing phases. Furthermore, were performed other analysis, like X-ray fluorescence, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy (author)

  9. Effect of anodization on corrosion behaviour and biocompatibility of ...

    Indian Academy of Sciences (India)

    Pores of some anodized samples are sealed by exposing the anodized surface in boiling water. Corrosion behaviour of the anodized specimen is studied in Ringer's solution at 30 ± 2 °C, using electrochemical impedance and cyclic polarization technique. Biocompatibility of the anodized surface is accessed using MG63 ...

  10. Anodic titania films as anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Lindsay, M.J.; Blackford, M.G.; Attard, D.J.; Luca, V.; Skyllas-Kazacos, M.; Griffith, C.S.

    2007-01-01

    Titania thin films were prepared through the anodisation of titanium metal in a 1.0 M sulphuric acid solution at 80 o C utilising a series of pulsed dc constant currents of increasing magnitude. Films were then tested as a potential anode material for lithium batteries using a variety of techniques. Electrochemical testing revealed that the films (3.8 cm 2 ) offered good rate capabilities affording a constant capacity of 48 μAh for a constant current of 10 μA which decreased to 25 μAh on increasing the current to 1250 μA. Cyclic voltammetry was conducted over a range of scan rates from which capacitive currents were examined and rate constants, transfer coefficients and diffusion coefficients calculated. Electrochemical impedance spectroscopy was conducted over six potentials in the range 0.1-2.7 V with the experimental data successfully modelled using an equivalent circuit with the notation R(Q(RW))C. TEM observation of focussed ion beam milled cross-sections showed significant structural differences between the as-anodised film and those cycled in a lithium battery. Raman spectroscopy showed that the films had an anatase character that transformed into an unidentified lithium-containing, titanate phase on cycling. Based on a film thickness of 100 nm, and assuming density of 4 g cm -3 such films offered a stable capacity of 316 mAh g -1

  11. Structural Engineering of Nanoporous Anodic Alumina Photonic Crystals by Sawtooth-like Pulse Anodization.

    Science.gov (United States)

    Law, Cheryl Suwen; Santos, Abel; Nemati, Mahdieh; Losic, Dusan

    2016-06-01

    This study presents a sawtooth-like pulse anodization approach aiming to create a new type of photonic crystal structure based on nanoporous anodic alumina. This nanofabrication approach enables the engineering of the effective medium of nanoporous anodic alumina in a sawtooth-like manner with precision. The manipulation of various anodization parameters such as anodization period, anodization amplitude, number of anodization pulses, ramp ratio and pore widening time allows a precise control and fine-tuning of the optical properties (i.e., characteristic transmission peaks and interferometric colors) exhibited by nanoporous anodic alumina photonic crystals (NAA-PCs). The effect of these anodization parameters on the photonic properties of NAA-PCs is systematically evaluated for the establishment of a fabrication methodology toward NAA-PCs with tunable optical properties. The effective medium of the resulting NAA-PCs is demonstrated to be optimal for the development of optical sensing platforms in combination with reflectometric interference spectroscopy (RIfS). This application is demonstrated by monitoring in real-time the formation of monolayers of thiol molecules (11-mercaptoundecanoic acid) on the surface of gold-coated NAA-PCs. The obtained results reveal that the adsorption mechanism between thiol molecules and gold-coated NAA-PCs follows a Langmuir isotherm model, indicating a monolayer sorption mechanism.

  12. Macrokinetic relationships between anodic processes in chlorine electrolysis on ruthenium-titanium oxide anodes

    International Nuclear Information System (INIS)

    Evdokimov, S.V.

    1999-01-01

    Effect of porosity on kinetics of the main (chlorine evolution) and side (oxygen evolution and anodic dissolution of ruthenium dioxide) reactions for chlorine electrolysis conditions has been analyzed. Making allowance for chlorine hydrolysis secondary reaction, the distribution of chlorine concentration, solution pH and current densities of the main and side processes over the porous anode depth, have been found. It is shown that solution acidification in the anode pores due to chlorine hydrolysis can bring about replacement of oxygen evolution and ruthenium dioxide dissolution side reactions toward the porous anode external sides thus affecting its selectivity and corrosion resistance [ru

  13. Electrometallurgy of copper refinery anode slimes

    Science.gov (United States)

    Scott, J. D.

    1990-08-01

    High-selenium copper refinery anode slimes form two separate and dynamically evolving series of compounds with increasing electrolysis time. In one, silver is progressively added to non-stoichiometric copper selenides, both those originally present in the anode and those formed subsequently in the slime layer, and in the other, silver-poor copper selenides undergo a dis-continuous crystallographic sequence of anodic-oxidative transformations. The silver-to-selenium molar ratio in the as-cast anode and the current density of electrorefining can be used to construct predominance diagrams for both series and, thus, to predict the final bulk “mineralogy” of the slimes. Although totally incorrect in detail, these bulk data are sufficiently accurate to provide explanations for several processing problems which have been experienced by Kidd Creek Division, Falconbridge Ltd., in its commercial tankhouse. They form the basis for a computer model which predicts final cathode quality from chemical analyses of smelter feed.

  14. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  15. Fibrous zinc anodes for high power batteries

    Science.gov (United States)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  16. New High-Energy Nanofiber Anode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiangwu [North Carolina State Univ., Raleigh, NC (United States); Fedkiw, Peter [North Carolina State Univ., Raleigh, NC (United States); Khan, Saad [North Carolina State Univ., Raleigh, NC (United States); Huang, Alex [North Carolina State Univ., Raleigh, NC (United States); Fan, Jiang [North Carolina State Univ., Raleigh, NC (United States)

    2013-11-15

    The overall goal of the proposed work was to use electrospinning technology to integrate dissimilar materials (lithium alloy and carbon) into novel composite nanofiber anodes, which simultaneously had high energy density, reduced cost, and improved abuse tolerance. The nanofiber structure allowed the anodes to withstand repeated cycles of expansion and contraction. These composite nanofibers were electrospun into nonwoven fabrics with thickness of 50 μm or more, and then directly used as anodes in a lithium-ion battery. This eliminated the presence of non-active materials (e.g., conducting carbon black and polymer binder) and resulted in high energy and power densities. The nonwoven anode structure also provided a large electrode-electrolyte interface and, hence, high rate capacity and good lowtemperature performance capability. Following are detailed objectives for three proposed project periods. During the first six months: Obtain anodes capable of initial specific capacities of 650 mAh/g and achieve ~50 full charge/discharge cycles in small laboratory scale cells (50 to 100 mAh) at the 1C rate with less than 20 percent capacity fade; In the middle of project period: Assemble, cycle, and evaluate 18650 cells using proposed anode materials, and demonstrate practical and useful cycle life (750 cycles of ~70% state of charge swing with less than 20% capacity fade) in 18650 cells with at least twice improvement in the specific capacity than that of conventional graphite electrodes; At the end of project period: Deliver 18650 cells containing proposed anode materials, and achieve specific capacities greater than 1200 mAh/g and cycle life longer than 5000 cycles of ~70% state of charge swing with less than 20% capacity fade.

  17. Electrolytic Cell For Production Of Aluminum Employing Planar Anodes.

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Robert J. (Goldendale, WA); Mezner, Michael B. (Sandy, OR); Bradford, Donald R (Underwood, WA)

    2004-10-05

    A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising providing a molten salt electrolyte having alumina dissolved therein in an electrolytic cell. A plurality of anodes and cathodes having planar surfaces are disposed in a generally vertical orientation in the electrolyte, the anodes and cathodes arranged in alternating or interleaving relationship to provide anode planar surfaces disposed opposite cathode planar surfaces, the anode comprised of carbon. Electric current is passed through anodes and through the electrolyte to the cathodes depositing aluminum at the cathodes and forming carbon containing gas at the anodes.

  18. Anodic oxidation of Ta/Fe alloys

    International Nuclear Information System (INIS)

    Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

    2003-01-01

    The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

  19. An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ferdman, Alla

    2005-05-11

    The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having optimized composition and structure were produced for testing in operating conditions of copper electrowinning and EMD production. Bench-scale, mini-pilot scale and pilot scale tests were performed. The test anodes were of both a plate design and a flow-through cylindrical design. The cylindrical anodes were composed of cylinders containing titanium inner rods and fitting over titanium-lead bushings. The cylindrical design allows the electrolyte to flow through the anode, which enhances diffusion of the electrolyte reactants. The cylindrical anodes demonstrate higher mass transport capabilities and increased electrical efficiency compared to the plate anodes. Copper electrowinning represents the primary target market for the titanium-lead anode. A full-size cylindrical anode performance in copper electrowinning conditions was monitored over a year. The test anode to cathode voltage was stable in the 1.8 to 2.0 volt range. Copper cathode morphology was very smooth and uniform. There was no

  20. Silicon Whisker and Carbon Nanofiber Composite Anode

    Science.gov (United States)

    Lang, Christopher M.

    2015-01-01

    Phase II Objectives: Demonstrate production levels of grams per batch; Achieve full cell anode capacity of greater than 1,000 mAh/g at a charge rate of 10 (C/10) and 0 degree C; Establish a full cell cycle life of over 300 cycles; Display an operating temperature of negative 30 degrees C to plus 30 degrees C; Demonstrate a rate capability of C/5 or higher; Deliver to NASA three 2.5 Ah cells (energy density greater than 220 Wh/kg); Exhibit the safety features of the anode and full cells; Design a 1 kWh prismatic battery pack.

  1. The effect of ethylene glycol on pore arrangement of anodic aluminium oxide prepared by hard anodization

    Science.gov (United States)

    Guo, Yang; Zhang, Li; Han, Mangui; Wang, Xin; Xie, Jianliang; Deng, Longjiang

    2018-03-01

    The influence of the addition of ethylene glycol (EG) on the pore self-ordering process in anodic aluminium oxide (AAO) membranes prepared by hard anodization (HA) was investigated. It was illustrated that EG has a substantial effect on the pore arrangement of AAO, and it was found that a smaller pore size can be obtained with an EG concentration reaching 20 wt% in aqueous electrolyte. The number of estimated defects of AAO increases significantly with an increase in EG concentration to 50 wt%. Excellent ordering of pores was realized when the samples were anodized in the 30 wt%-EG-containing aqueous electrolyte.

  2. Silicon Whisker and Carbon Nanofiber Composite Anode, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to develop a silicon whisker and carbon nanofiber composite anode for lithium ion batteries on a Phase I program. This anode...

  3. Silicon-Based Anode and Method for Manufacturing the Same

    Science.gov (United States)

    Yushin, Gleb Nikolayevich (Inventor); Luzinov, Igor (Inventor); Zdyrko, Bogdan (Inventor); Magasinski, Alexandre (Inventor)

    2017-01-01

    A silicon-based anode comprising silicon, a carbon coating that coats the surface of the silicon, a polyvinyl acid that binds to at least a portion of the silicon, and vinylene carbonate that seals the interface between the silicon and the polyvinyl acid. Because of its properties, polyvinyl acid binders offer improved anode stability, tunable properties, and many other attractive attributes for silicon-based anodes, which enable the anode to withstand silicon cycles of expansion and contraction during charging and discharging.

  4. Hollow Anode Cascading Plasma Focus | Alabraba | Journal of the ...

    African Journals Online (AJOL)

    Using the 3-phase model for each focus event, the 9-phase, two solid disc auxiliary anode cascading plasma focus has been extended to include holes at the center of each cascade anode (hereafter referred to as hollow anode cascading focus) with a view of increasing the neutron yield with each focus event. Results ...

  5. Anode heat transfer in a constricted tube arc.

    Science.gov (United States)

    Lukens, L. A.; Incropera, F. P.

    1971-01-01

    The complex energy exchange mechanisms occurring on the most severely heated component of an arc constrictor, the anode, have been investigated. Measurements performed to determine the anode heat flux for a cascade, atmospheric argon arc of the Maecker type are described. The results are used to check the validity of an existing anode heat transfer model.

  6. Anodization of Aluminium using a fast two-step process

    Indian Academy of Sciences (India)

    the electrolyte for the first anodization to form pits on. Al substrate, while in second anodization these pits act as the pattern for nanopore formation.26 Nanoporous alumina is used in the development of thermoelectric devices using metamaterials and for energy harvest- ing. Anodized magnetic nanohole arrays are used in.

  7. Silicon Whisker and Carbon Nanofiber Composite Anode

    Science.gov (United States)

    Ma, Junqing (Inventor); Newman, Aron (Inventor); Lennhoff, John (Inventor)

    2015-01-01

    A carbon nanofiber can have a surface and include at least one crystalline whisker extending from the surface of the carbon nanofiber. A battery anode composition can be formed from a plurality of carbon nanofibers each including a plurality of crystalline whiskers.

  8. Growth of anodic films on niobium

    International Nuclear Information System (INIS)

    Gomes, M.A.B.; Bulhoes, L.O.S.

    1988-01-01

    The analysis of the response of the galvanostatic growth of anodic films on niobium metal in aqueous solutions is shown. The first spark voltage showed a dependence upon value of current density that could be explained as the incorporation of anions into the film. (M.J.C.) [pt

  9. Anode materials for lithium-ion batteries

    Science.gov (United States)

    Sunkara, Mahendra Kumar; Meduri, Praveen; Sumanasekera, Gamini

    2014-12-30

    An anode material for lithium-ion batteries is provided that comprises an elongated core structure capable of forming an alloy with lithium; and a plurality of nanostructures placed on a surface of the core structure, with each nanostructure being capable of forming an alloy with lithium and spaced at a predetermined distance from adjacent nanostructures.

  10. Linear sweep anodic stripping voltammetry: Determination of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 6. Linear sweep anodic stripping voltammetry: Determination of Chromium (VI) using synthesized gold nanoparticles modified screen-printed electrode. Salamatu Aliyu Tukur Nor Azah Yusof Reza Hajian. Regular Articles Volume 127 Issue 6 June 2015 pp ...

  11. Hybrid anode for semiconductor radiation detectors

    Science.gov (United States)

    Yang, Ge; Bolotnikov, Aleksey E; Camarda, Guiseppe; Cui, Yonggang; Hossain, Anwar; Kim, Ki Hyun; James, Ralph B

    2013-11-19

    The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

  12. Characterization of nanopores ordering in anodic alumina

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.; Piraux, L.

    2008-01-01

    A simple characterization method of the ordering of the nanopores is described for nanoporous anodized aluminium oxides. The method starts with image analysis on scanning electron microscopy representations for the purpose to find repetitive shapes and their centres, i.e. nanopores. Then triangles...

  13. Quantitative relationship between nanotube length and anodizing current during constant current anodization

    International Nuclear Information System (INIS)

    Zhang, Yulian; Cheng, Weijie; Du, Fei; Zhang, Shaoyu; Ma, Weihua; Li, Dongdong; Song, Ye; Zhu, Xufei

    2015-01-01

    Highlights: • Ti anodization was performed by constant current rather than constant voltage. • The nanotube length was controlled by ionic current rather than dissolution current. • Electronic current can be estimated by the nanotube length and the anodizing current. • Dissolution reaction hardly contributes electric current across the barrier layer. - Abstract: The growth kinetics of anodic TiO 2 nanotubes (ATNTs) still remains unclear. ATNTs are generally fabricated under potentiostatic conditions rather than galvanostatic ones. The quantitative relationship between nanotube length and anodizing current (J total ) is difficult to determine, because the variable J total includes ionic current (J ion ) (also called oxide growth current J grow =J ion ) and electronic current (J e ), which cannot be separated from each other. One successful approach to achieve this objective is to use constant current anodization rather than constant voltage anodization, that is, through quantitative comparison between the nanotube length and the known J total during constant current anodization, we can estimate the relative magnitudes of J grow and J e . The nanotubes with lengths of 1.24, 2.23, 3.51 and 4.70 μm, were formed under constant currents (J total ) of 15, 20, 25 and 30 mA, respectively. The relationship between nanotube length (y) and anodizing current (x =J total =J grow +J e ) can be expressed by a fitting equation: y=0.23(x-10.13), from which J grow (J grow = x -10.13) and J e (∼10.13 mA) could be inferred under the present conditions. Meanwhile, the same conclusion could also be deduced from the oxide volume data. These results indicate that the nanotube growth is attributed to the oxide growth current rather than the dissolution current.

  14. Transparent Aluminum Oxide Films by Edge Anodization

    Science.gov (United States)

    Stott, Jonathan; Greenwood, Thomas; Winn, David

    In this paper we present our recent work on manufacturing thin (3 - 5 μm) films of porous aluminum(III) oxide [PAO] using a novel edge-anodization technique. With this modified anodization process, we are able to create transparent PAO films on top of insulating substrates such as glass or plastic. By controlling the processing parameters, the index of refraction of PAO films can be engineered to match the substrate, which gives us a durable reflection-free and scratch-resistant coating over conventional optics or LCD displays. Eventually we hope to create ordered porous aluminum oxide cladding around an optical fiber core, which could have a number of interesting optical properties if the pore spacing can be matched to the wavelength of light in the fiber. This work was funded by Fairfield University startup funding.

  15. Fuel cell anode configuration for CO tolerance

    Science.gov (United States)

    Uribe, Francisco A.; Zawodzinski, Thomas A.

    2004-11-16

    A polymer electrolyte fuel cell (PEFC) is designed to operate on a reformate fuel stream containing oxygen and diluted hydrogen fuel with CO impurities. A polymer electrolyte membrane has an electrocatalytic surface formed from an electrocatalyst mixed with the polymer and bonded on an anode side of the membrane. An anode backing is formed of a porous electrically conductive material and has a first surface abutting the electrocatalytic surface and a second surface facing away from the membrane. The second surface has an oxidation catalyst layer effective to catalyze the oxidation of CO by oxygen present in the fuel stream where at least the layer of oxidation catalyst is formed of a non-precious metal oxidation catalyst selected from the group consisting of Cu, Fe, Co, Tb, W, Mo, Sn, and oxides thereof, and other metals having at least two low oxidation states.

  16. Theoretical Investigation of a Hot Refractory Anode Vacuum Arc

    International Nuclear Information System (INIS)

    Beilis, I.I.; Boxman, R.L.; Goldsmith, S.

    1999-01-01

    The two principal modes of the vacuum arc arc the multi-cathode spot and the anode spot vacuum arc discharges. In both cases the current is conducted in plasma that is generated on relatively small areas on the relevant electrode surface. The hot anode vacuum arc (HAVA) is another mode of the vacuum arc in which the plasma is produced by material evaporation over the whole surface of a high temperature anode heated by the arc itself. In the present work, a model of a new type of the HAVA, recently discovered in the Electrical Discharges and Plasma Laboratory of TAU, is considered. In this mode of the HAVA the anode is made of a thermally isolated refractory material (graphite), whereas the water cooled cathode is fabricated from a more volatile material (copper). The discharge starts in the multi-cathode spot mode and after a transition period, during which the anode is heated by the arc, re-evaporated cathode material is released from the hot anode surface and becomes the main source of the arc plasma. At steady state, anode temperature exceeds a certain critical value. No evaporation of anode refractory material occurs during arc operation. This arc mode is labeled Hot Refractory Anode Vacuum Arc (HRAVA). The theoretical description of the HRAVA is accomplished by a plasma model that includes equations of mass, momentum, energy, and electrical current conservation, and by an anode thermal model that describes the anode thermal balance. The plasma model also considers radial expansion of the plasma from the interelectrode region. A self-consistent solution of the plasma and anode models was obtained. Plasma electron temperature, plasma density, plasma energy flux to the anode, and anode temperature distribution were calculated for several arc currents in the range 175 - 500 A. In the steady-state arc operation, anode surface temperature was calculated to be in the range 1800 - 2600 degree K, electron temperature is about 1 eV, effective anode voltage is about 6 V

  17. Spinal Anodes for Lithium-Ion Batteries

    CSIR Research Space (South Africa)

    Ferg, E

    1994-11-01

    Full Text Available Anodes of Li4Mn5O12, Li4Ti5O12, and Li2Mn4O9 with a spinel-type structure have been evaluated in room-temperature lithium cells. The cathodes that were selected for this study were the stabilized spinels, Li1.03Mn1.97O4 and LiZn0.025Mn1.95O4...

  18. High performance anode for advanced Li batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lake, Carla [Applied Sciences, Inc., Cedarville, OH (United States)

    2015-11-02

    The overall objective of this Phase I SBIR effort was to advance the manufacturing technology for ASI’s Si-CNF high-performance anode by creating a framework for large volume production and utilization of low-cost Si-coated carbon nanofibers (Si-CNF) for the battery industry. This project explores the use of nano-structured silicon which is deposited on a nano-scale carbon filament to achieve the benefits of high cycle life and high charge capacity without the consequent fading of, or failure in the capacity resulting from stress-induced fracturing of the Si particles and de-coupling from the electrode. ASI’s patented coating process distinguishes itself from others, in that it is highly reproducible, readily scalable and results in a Si-CNF composite structure containing 25-30% silicon, with a compositionally graded interface at the Si-CNF interface that significantly improve cycling stability and enhances adhesion of silicon to the carbon fiber support. In Phase I, the team demonstrated the production of the Si-CNF anode material can successfully be transitioned from a static bench-scale reactor into a fluidized bed reactor. In addition, ASI made significant progress in the development of low cost, quick testing methods which can be performed on silicon coated CNFs as a means of quality control. To date, weight change, density, and cycling performance were the key metrics used to validate the high performance anode material. Under this effort, ASI made strides to establish a quality control protocol for the large volume production of Si-CNFs and has identified several key technical thrusts for future work. Using the results of this Phase I effort as a foundation, ASI has defined a path forward to commercialize and deliver high volume and low-cost production of SI-CNF material for anodes in Li-ion batteries.

  19. Improvement in direct methanol fuel cell performance by treating the anode at high anodic potential

    Science.gov (United States)

    Joghee, Prabhuram; Pylypenko, Svitlana; Wood, Kevin; Corpuz, April; Bender, Guido; Dinh, Huyen N.; O'Hayre, Ryan

    2014-01-01

    This work investigates the effect of a high anodic potential treatment protocol on the performance of a direct methanol fuel cell (DMFC). DMFC membrane electrode assemblies (MEAs) with PtRu/C (Hi-spec 5000) anode catalyst are subjected to anodic treatment (AT) at 0.8 V vs. DHE using potentiostatic method. Despite causing a slight decrease in the electrochemical surface area (ECSA) of the anode, associated with ruthenium dissolution, AT results in significant improvement in DMFC performance in the ohmic and mass transfer regions and increases the maximum power density by ∼15%. Furthermore, AT improves the long-term DMFC stability by reducing the degradation of the anode catalyst. From XPS investigation, it is hypothesized that the improved performance of AT-treated MEAs is related to an improved interface between the catalyst and Nafion ionomer. Among potential explanations, this improvement may be caused by incorporation of the ionomer within the secondary pores of PtRu/C agglomerates, which generates a percolating network of ionomer between PtRu/C agglomerates in the catalyst layer. Furthermore, the decreased concentration of hydrophobic CF2 groups may help to enhance the hydrophilicity of the catalyst layer, thereby increasing the accessibility of methanol and resulting in better performance in the high current density region.

  20. The importance of anodic discharge of H2O in anodic oxygen-transfer reactions

    International Nuclear Information System (INIS)

    Vitt, J.E.; Johnson, D.C.

    1992-01-01

    This paper discusses difference voltammetry at rotated disk electrodes which are applied to a study of several anodic O-transfer reactions that appear to occur concurrently with O 2 evolution. This voltammetric technique was useful for extracting the rotation-dependent component of the total current from the large, virtually rotation-independent current for O 2 evolution. Data for oxidation of I - at Pt, Au, Pd, Ir, and glassy carbon electrodes show that the E 1/2 for IO - 3 production is correlated with the overpotential for O 2 evolution at these electrode materials. Data obtained at an Ir electrode for various reactions with widely varying E o values reveal uniform E 1/2 values closely correlated with the potential for onset of O 2 evolution in both alkaline and acidic solutions. The results support the conclusion that the anodic discharge of H 2 O is a prerequisite of these anodic O-transfer mechanisms

  1. Fundamental Investigation of Si Anode in Li-Ion Cells

    Science.gov (United States)

    Wu, James J.; Bennett, William R.

    2012-01-01

    Silicon is a promising and attractive anode material to replace graphite for high capacity lithium ion cells since its theoretical capacity is approximately 10 times of graphite and it is an abundant element on earth. However, there are challenges associated with using silicon as Li-ion anode due to the significant first cycle irreversible capacity loss and subsequent rapid capacity fade during cycling. In this paper, cyclic voltammetry and electrochemical impedance spectroscopy are used to build a fundamental understanding of silicon anodes. The results show that it is difficult to form the SEI film on the surface of Si anode during the first cycle, the lithium ion insertion and de-insertion kinetics for Si are sluggish, and the cell internal resistance changes with the state of lithiation after electrochemical cycling. These results are compared with those for extensively studied graphite anodes. The understanding gained from this study will help to design better Si anodes.

  2. Redox Stable Anodes for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Guoliang eXiao

    2014-06-01

    Full Text Available Solid oxide fuel cells (SOFCs can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as the fuel. This review aims to highlight recent progresses on improving redox stability of the conventional Ni-based anode through microstructure optimization and exploration of alternative ceramic-based anode materials.

  3. Fabrication of ultra thin anodic aluminium oxide membranes by low anodization voltages

    Science.gov (United States)

    Pastore, I.; Poplausks, R.; Apsite, I.; Pastare, I.; Lombardi, F.; Erts, D.

    2011-06-01

    Formation of ultrathin anodised aluminium oxide (AAO) membranes with high aspect ratio by Al anodization in sulphuric and oxalic acids at low potentials was investigated. Low anodization potentials ensure slow electrochemical reaction speeds and formation of AAO membranes with pore diameter and thickness below 20 nm and 70 nm respectively. Minimum time necessary for formation of continuous AAO membranes was determined. AAO membrane pore surface was covered with polymer Paraloid B72TM to transport it to the selected substrate. The fabricated ultra thin AAO membranes could be used to fabricate nanodot arrays on different surfaces.

  4. Battery, especially for portable devices, has an anode containing silicon

    OpenAIRE

    Kan, S.Y.

    2002-01-01

    The anode (2) contains silicon. A battery with a silicon-containing anode is claimed. An Independent claim is also included for a method used to make the battery, comprising the doping of a silicon substrate (1) with charge capacity-increasing material (preferably boron, phosphorous or arsenic), etching the doped substrate layer in order to increase its porosity, and applying a cathode (3) in the form of a lithium oxide compound onto the resulting anode and applying an electrolyte (4) to the ...

  5. Arc attachment at HID anodes: measurements and interpretation

    International Nuclear Information System (INIS)

    Redwitz, M; Dabringhausen, L; Lichtenberg, S; Langenscheidt, O; Heberlein, J; Mentel, J

    2006-01-01

    Anodes for high intensity discharge lamps made of cylindrical tungsten rods and the plasma in front of them are investigated in a special lamp filled with argon and other noble gases at pressures of 0.1-1 MPa. The arc attachment on these anodes takes place in a constricted mode. The temperature is measured pyrometrically along the electrode axis and the anode fall electrically. The electron temperature, T e , and the electron density, n e , within the anodic boundary layer are determined spectroscopically with high spatial resolution. It is found that the power input into the anode increases nearly linearly with the arc current. The proportionality constant is mainly determined by the work function of the electrode material and T e but is independent of the electrically measured anode fall and scarcely dependent on the electrode dimensions. The constriction is more pronounced in cold anodes, with maxima of T e and n e in front of the electrode surface, than on hot anodes with thermionic electron emission and vaporization of the electrode material. The distances of the T e - and n e -maxima from the anode surface are increased and T e is reduced in front of the anode with increasing anode temperature. The experimental findings may be explained by a model of the anodic boundary layer consisting of a thin sheath in front of the surface and a more extended constriction zone. The current and voltage are anti-parallel within the sheath. The power which is needed to sustain the sheath is supplied by an enhanced electrical power input into the constriction zone

  6. The influence of coke source on anode performance

    Science.gov (United States)

    Jonville, C.; Thomas, J. C.; Dreyer, C.

    1995-08-01

    The role of anode raw material has long been debated in the aluminum smelting industry. By examining data accumulated from two similar smelting operations of Aluminium Pechiney, this article focuses on the differences in performance of anodes that can be attributed to the raw materials. The results suggest that good anode performance can be obtained for a range of cokes, provided that the operation is well designed and carefully operated.

  7. Cooling for a rotating anode X-ray tube

    Science.gov (United States)

    Smither, Robert K.

    1998-01-01

    A method and apparatus for cooling a rotating anode X-ray tube. An electromagnetic motor is provided to rotate an X-ray anode with cooling passages in the anode. These cooling passages are coupled to a cooling structure located adjacent the electromagnetic motor. A liquid metal fills the passages of the cooling structure and electrical power is provided to the motor to rotate the anode and generate a rotating magnetic field which moves the liquid metal through the cooling passages and cooling structure.

  8. The corrosion protection of 2219-T87 aluminum by anodizing

    Science.gov (United States)

    Danford, M. D.

    1991-01-01

    Various types of anodizing coatings were studied for 2219-T87 aluminum. These include both type II and type III anodized coats which were water sealed and a newly developed and proprietary Magnaplate HCR (TM) coat. Results indicate that type II anodizing is not much superior to type II anodizing as far as corrosion protection for 2219-T87 aluminum is concerned. Magnaplate HCR (TM) coatings should provide superior corrosion protection over an extended period of time using a coating thickness of 51 microns (2.0 mils).

  9. Influence of the anodizing process variables on the acidic properties of anodic alumina films

    Directory of Open Access Journals (Sweden)

    D.E. Boldrini

    Full Text Available Abstract In the present work, the effect of the different variables involved in the process of aluminum anodizing on the total surface acidity of the samples obtained was studied. Aluminum foils were treated by the electro-chemical process of anodic anodizing within the following variable ranges: concentration = 1.5-2.5 M; temperature = 303-323 K; voltage = 10-20 V; time = 30-90 min. The total acidity of the samples was characterized by two different methods: acid-base titration using Hammett indicators and potentiometric titration. The results showed that anodizing time, temperature and concentration were the main variables that determined the surface acid properties of the samples, and to a lesser extent voltage. Acidity increased with increasing concentration of the electrolytic bath, whereas the rest of the variables had the opposite effect. The results obtained provide a novel tool for variable selection in order to use synthetized materials as catalytic supports, adding to previous research based on the morphology of alumina layers.

  10. X-ray tube with rotating anode

    International Nuclear Information System (INIS)

    1977-01-01

    Radiation tube, with a rotating anode is located in a vacuum tight housing by means of at least one bearing, characterised in that the bearing is a sliding bearing wherein at least the mutually working load contact surfaces consist mainly of a metal or metallic alloy and are not chemically attacked, as a bearing lubricant material is used containing a Ga-alloy, with a low melting point and a low vapour pressure, which is in direct contact with the metal working surfaces. (G.C.)

  11. Composite anode for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    de Guzman, Rhet C.; Ng, K.Y. Simon; Salley, Steven O.

    2018-03-06

    A composite anode for a lithium-ion battery is manufactured from silicon nanoparticles having diameters mostly under 10 nm; providing an oxide layer on the silicon nanoparticles; dispersing the silicon nanoparticles in a polar liquid; providing a graphene oxide suspension; mixing the polar liquid containing the dispersed silicone nanoparticles with the graphene oxide suspension to obtain a composite mixture; probe-sonicating the mixture for a predetermined time; filtering the composite mixture to obtain a solid composite; drying the composite; and reducing the composite to obtain graphene and silicon.

  12. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bulk...... and thin-film glasses were used in the bonding experiments. Bond quality was evaluated using a tensile test on structured dies. The effect of oxygen-based pre-treatments of the nitride surface on the bond quality has been evaluated. Bond strengths up to 35 Nrmm2 and yields up to 100% were obtained....

  13. Anodization of Copper in Chloride Media

    Science.gov (United States)

    1994-01-31

    in various media. In chloride-containing solution, seawater for example, the cuprous species CuCI and CuCl2" are major products of copper anodization...assumption was used in these determinations, which rendered only the foot of the voltammetric wave useful for calculating 132, and the formation of CuCI was...time-independent, and refers to steady-state currents at given potentials. In the present case of the formation of CuCI and CuCl2 , we are interested in

  14. Heterotrophic Anodic Denitrification in Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jakub Drewnowski

    2016-06-01

    Full Text Available Nowadays, pollution caused by energy production systems is a major environmental concern. Therefore, the development of sustainable energy sources is required. Amongst others, the microbial fuel cell (MFC seems to be a possible solution because it can produce clean energy at the same time that waste is stabilized. Unfortunately, mainly due to industrial discharges, the wastes could contain nitrates, or nitrates precursors such ammonia, which could lead to lower performance in terms of electricity production. In this work, the feasibility of coupling anodic denitrification process with electricity production in MFC and the effect of the nitrates over the MFC performance were studied. During the experiments, it was observed that the culture developed in the anodic chamber of the MFC presented a significant amount of denitrificative microorganisms. The MFC developed was able to denitrify up to 4 ppm, without affecting the current density exerted, of about 1 mA/cm2. Regarding the denitrification process, it must be highlighted that the maximum denitrification rate achieved with the culture was about 60 mg·NO3−·L−1·h−1. Based on these results, it can be stated that it is possible to remove nitrates and to produce energy, without negatively affecting the electrical performance, when the nitrate concentration is low.

  15. Alternative Anode Reaction for Copper Electrowinning

    Energy Technology Data Exchange (ETDEWEB)

    2005-07-01

    This report describes a project funded by the Department of Energy, with additional funding from Bechtel National, to develop a copper electrowinning process with lower costs and lower emissions than the current process. This new process also includes more energy efficient production by using catalytic-surfaced anodes and a different electrochemical couple in the electrolyte, providing an alternative oxidation reaction that requires up to 50% less energy than is currently required to electrowin the same quantity of copper. This alternative anode reaction, which oxidizes ferric ions to ferrous, with subsequent reduction back to ferric using sulfur dioxide, was demonstrated to be technically and operationally feasible. However, pure sulfur dioxide was determined to be prohibitively expensive and use of a sulfur burner, producing 12% SO{sub 2}, was deemed a viable alternative. This alternate, sulfur-burning process requires a sulfur burner, waste heat boiler, quench tower, and reaction towers. The electrolyte containing absorbed SO{sub 2} passes through activated carbon to regenerate the ferrous ion. Because this reaction produces sulfuric acid, excess acid removal by ion exchange is necessary and produces a low concentration acid suitable for leaching oxide copper minerals. If sulfide minerals are to be leached or the acid unneeded on site, hydrogen was demonstrated to be a potential reductant. Preliminary economics indicate that the process would only be viable if significant credits could be realized for electrical power produced by the sulfur burner and for acid if used for leaching of oxidized copper minerals on site.

  16. Optimal Conditions for Fast Charging and Long Cycling Stability of Silicon Microwire Anodes for Lithium Ion Batteries, and Comparison with the Performance of Other Si Anode Concepts

    OpenAIRE

    Enrique Quiroga-González; Jürgen Carstensen; Helmut Föll

    2013-01-01

    Cycling tests under various conditions have been performed for lithium ion battery anodes made from free-standing silicon microwires embedded at one end in a copper current collector. Optimum charging/discharging conditions have been found for which the anode shows negligible fading (< 0.001%) over 80 cycles; an outstanding result for this kind of anodes. Several performance parameters of the anode have been compared to the ones of other Si anode concepts, showing that especially the capacity...

  17. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1983-01-04

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  18. Coating for lithium anode, thionyl chloride active cathode electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Catanzarite, V.O.

    1981-10-20

    Electrochemical power cells having a cathode current collector, a combination liquid active cathode depolarizer electrolyte solvent and an anode that forms surface compounds when in intimate contact with the liquid cathode are enhanced by the addition of a passivation limiting film contiguous to said anode. The passivating film is a member of the cyanoacrilate family of organic compounds.

  19. Application of multi-walled carbon nanotubes to enhance anodic ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... Nambiar et al. 6929. Figure 1. The setup of the H-type microbial fuel cell system used. A: anode chamber; B: proton exchange membrane junction; C: cathode chamber; D: resistor on the external circuit; length of the anode-cathode chambers connector: 200 mm; inner diameter of the connector tube: 14 mm.

  20. Battery, especially for portable devices, has an anode containing silicon

    NARCIS (Netherlands)

    Kan, S.Y.

    2002-01-01

    The anode (2) contains silicon. A battery with a silicon-containing anode is claimed. An Independent claim is also included for a method used to make the battery, comprising the doping of a silicon substrate (1) with charge capacity-increasing material (preferably boron, phosphorous or arsenic),

  1. Formation of complex anodic films on porous alumina matrices

    Indian Academy of Sciences (India)

    The kinetics of growth of complex anodic alumina films was investigated. These films were formed by filling porous oxide films (matrices) having deep pores. The porous films (matrices) were obtained voltastatically in (COOH)2 aqueous solution under various voltages. The filling was done by re-anodization in an electrolyte ...

  2. Anodic dissolution of alloys during electrochemical dimensional machining of parts

    International Nuclear Information System (INIS)

    Davydov, A.D.

    1980-01-01

    Analysis of the main regularities of anodic dissolution of alloys at current high densities, which is necessary for the explanation and prediction of the results of electrochemical dimensional machining of parts, is carried out. Examples when chemical composition produces the determining effect upon anodic behaviour and electrochemical treatment of the alloys are analyzed

  3. DMFC anode polarization: Experimental analysis and model validation

    Science.gov (United States)

    Casalegno, A.; Marchesi, R.

    Anode two-phase flow has an important influence on DMFC performance and methanol crossover. In order to elucidate two-phase flow influence on anode performance, in this work, anode polarization is investigated combining experimental and modelling approach. A systematic experimental analysis of operating conditions influence on anode polarization is presented. Hysteresis due to operating condition is observed; experimental results suggest that it arises from methanol accumulation and has to be considered in evaluating DMFC performances and measurements reproducibility. A model of DMFC anode polarization is presented and utilised as tool to investigate anode two-phase flow. The proposed analysis permits one to produce a confident interpretation of the main involved phenomena. In particular, it confirms that methanol electro-oxidation kinetics is weakly dependent on methanol concentration and that methanol transport in gas phase produces an important contribution in anode feeding. Moreover, it emphasises the possibility to optimise anode flow rate in order to improve DMFC performance and reduce methanol crossover.

  4. Plasmonic properties of gold-coated nanoporous anodic alumina ...

    Indian Academy of Sciences (India)

    Abstract. Anodization of aluminium surfaces containing linearly oriented scratches leads to the formation of nanoporous anodic alumina (NAA) with the nanopores arranged preferentially along the scratch marks. NAA, when coated with a thin gold film, support plasmonic resonances. Dark-field spectroscopy revealed that ...

  5. Formation of complex anodic films on porous alumina matrices

    Indian Academy of Sciences (India)

    Unknown

    follow the metal surface profile. The porous films are formed in electrolytes dissolving the ... investigated during anodization of different valve metals including Al (Andreeva and Ikonopisov 1970). The vali- .... age (Uf = 400 V) in order to finish the re-anodization just before reaching the breakdown voltage. From the kinetic ...

  6. Electrochemical oxidation of syngas on nickel and ceria anodes

    NARCIS (Netherlands)

    Tabish, A.N.; Patel, H.C.; Purushothaman Vellayani, A.

    2017-01-01

    Fuel flexibility of solid oxide fuel cells enables the use of low cost and practical fuels like syngas. Understanding of the oxidation kinetics with syngas is essential for proper selection of anode material and its design optimization. Using nickel and ceria pattern anodes, we study the

  7. Anodic oxide growth on Zr in neutral aqueous solution

    Indian Academy of Sciences (India)

    Abstract. Anodization and subsequent cathodic reactions on a thin-film sample of Zr were studied with in-situ neutron reflectometry (NR) and electrochemical impedance spec- troscopy (EIS). The NR results during anodization showed the originally 485 Å thick Zr film generally behaved similar to a bulk electrode in neutral ...

  8. Unique Reduced Graphene Oxide as Efficient Anode Material in Li ...

    Indian Academy of Sciences (India)

    19

    SRGO) was explicated as anode material in ... motivation behind testing SRGO as anode material in LIB is owing to its previously reported characteristics [1-3] like high ... Cycling performance of SRGO is shown in Fig. 2 which clearly indicates that ...

  9. Application of multi-walled carbon nanotubes to enhance anodic ...

    African Journals Online (AJOL)

    The effect of multi-walled carbon nanotube (MWCNT) modification of anodes and the optimisation of relevant parameters thereof for application in an Enterobacter cloacae microbial fuel cell were examined. The H – type microbial fuel cells were used for the fundamental studies, with a carbon sheet as a control anode and ...

  10. Cathode Dependence of Liquid-Alloy Na-K Anodes.

    Science.gov (United States)

    Xue, Leigang; Gao, Hongcai; Li, Yutao; Goodenough, John B

    2018-03-07

    Alkali ions can be plated dendrite-free into a liquid alkali-metal anode. Commercialized Na-S battery technology operates above 300 °C. A low-cost Na-K alloy is liquid at 25 °C from 9.2 to 58.2 wt% of sodium; sodium and/or potassium can be plated dendrite-free in the liquid range at room temperature. The co-existence of two alkali metals in an anode raises a question: whether the liquid Na-K alloy acts as a Na or a K anode. Here we show the alkali-metal that is stripped from the liquid Na-K anode is dependent on the preference of the cathode host. It acts as the anode of a sodium rechargeable cell if the cathode host structure selectively accepts only Na + ions; as the anode of a potassium rechargeable cell if the cathode accepts K + ions in preference to Na + ions. This dual-anode behavior means the liquid Na-K alkali-alloy can be applied as a dendrite-free anode in Na-metal batteries as well as K-metal batteries.

  11. Fundamental Investigation of Silicon Anode in Lithium-Ion Cells

    Science.gov (United States)

    Wu, James J.; Bennett, William R.

    2012-01-01

    Silicon is a promising and attractive anode material to replace graphite for high capacity lithium ion cells since its theoretical capacity is 10 times of graphite and it is an abundant element on Earth. However, there are challenges associated with using silicon as Li-ion anode due to the significant first cycle irreversible capacity loss and subsequent rapid capacity fade during cycling. Understanding solid electrolyte interphase (SEI) formation along with the lithium ion insertion/de-insertion kinetics in silicon anodes will provide greater insight into overcoming these issues, thereby lead to better cycle performance. In this paper, cyclic voltammetry and electrochemical impedance spectroscopy are used to build a fundamental understanding of silicon anodes. The results show that it is difficult to form the SEI film on the surface of a Si anode during the first cycle; the lithium ion insertion and de-insertion kinetics for Si are sluggish, and the cell internal resistance changes with the state of lithiation after electrochemical cycling. These results are compared with those for extensively studied graphite anodes. The understanding gained from this study will help to design better Si anodes, and the combination of cyclic voltammetry with impedance spectroscopy provides a useful tool to evaluate the effectiveness of the design modifications on the Si anode performance.

  12. Interfacial chemistry of zinc anodes for reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Covino, B.S. Jr.; Bullard, S.J.; Cramer, S.D.; Holcomb, G.R. [Dept. of Energy, Albany, OR (United States). Albany Research Center; McGill, G.E.; Cryer, C.B. [Oregon Dept. of Transportation, Salem, OR (United States); Stoneman, A. [International Lead Zinc Research Organization, Research Triangle Park, NC (United States); Carter, R.R. [California Dept. of Transportation, Sacramento, CA (United States)

    1997-12-01

    Thermally-sprayed zinc anodes are used in both galvanic and impressed current cathodic protection systems for reinforced concrete structures. The Albany Research Center, in collaboration with the Oregon Department of Transportation, has been studying the effect of electrochemical aging on the bond strength of zinc anodes for bridge cathodic protection systems. Changes in anode bond strength and other anode properties can be explained by the chemistry of the zinc-concrete interface. The chemistry of the zinc-concrete interface in laboratory electrochemical aging studies is compared with that of several bridges with thermal-sprayed zinc anodes and which have been in service for 5 to 10 years using both galvanic and impressed current cathodic protection systems. The bridges are the Cape Creek Bridge on the Oregon coast and the East Camino Undercrossing near Placerville, CA. Also reported are interfacial chemistry results for galvanized steel rebar from the 48 year old Longbird Bridge in Bermuda.

  13. Analysis and design of double-anode magnetron injection gun

    International Nuclear Information System (INIS)

    Yang Tie; Niu Xinjian; Liu Yinghui

    2013-01-01

    Based on electro-optical theory and adiabatic compression theory, a double-anode magnetic injection gun for TE 34,19 , 170 GHz gyrotron was analyzed and designed with EGUN software. Concerning with the factors such as positions of anode and magnetic field distance between anodes, we obtained the result that the velocity ratio of electron beam approximated 1.3, and the velocity spread was under 3%. Furthermore, we found that electron beam was sensitive with these factors, such as that the velocity ratio decreased when the distance between anodes increased, while the velocity spread decreased first and then increased. The double-anode magnetic injection gun is employed in the experiments of gyrotron. (authors)

  14. Growth of anatase titanium dioxide nanotubes via anodization

    Directory of Open Access Journals (Sweden)

    Ed Adrian Dilla

    2012-06-01

    Full Text Available In this work, titanium dioxide nanotubes were grown via anodization of sputtered titanium thin films using different anodization parameters in order to formulate a method of producing long anatase titanium dioxide nanotubes intended for solar cell applications. The morphological features of the nanotubes grown via anodization were explored using a Philips XL30 Field Emission Scanning Electron Microscope. Furthermore, the grown nanotubes were also subjected to X-ray diffraction and Raman spectroscopy in order to investigate the effect of the predominant crystal orientation of the parent titanium thin film on the crystal phase of the nanotubes. After optimizing the anodization parameters, nanotubes with anatase TiO2 crystal phase and tube length more than 2 microns was produced from parent titanium thin films with predominant Ti(010 crystal orientation and using ammonium fluoride in ethylene glycol as an electrolyte with a working voltage equal to 60V during 1-hour anodization runs.

  15. Recovery of plutonium from electrorefining anode heels at Savannah River

    International Nuclear Information System (INIS)

    Gray, J.H.; Gray, L.W.; Karraker, D.G.

    1987-03-01

    In a joint effort, the Savannah River Laboratory (SRL), Savannah River Plant (SRP), and the Rocky Flats Plant (RFP) have developed two processes to recover plutonium from electrorefining anode heel residues. Aqueous dissolution of anode heel metal was demonstrated at SRL on a laboratory scale and on a larger pilot scale using either sulfamic acid or nitric acid-hydrazine-fluoride solutions. This direct anode heel metal dissolution requires the use of a geometrically favorable dissolver. The second process developed involves first diluting the plutonium in the anode heel residues by alloying with aluminum. The alloyed anode heel plutonium can then be dissolved using a nitric acid-fluoride-mercury(II) solution in large non-geometrically favorable equipment where nuclear safety is ensured by concentration control

  16. Natural gas anodes for aluminium electrolysis in molten fluorides.

    Science.gov (United States)

    Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy

    2016-08-15

    Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse gases (CO2 and PFC). A new concept has been suggested where methane is supplied through the anode so that the CO2 emissions may be reduced significantly, the PFC emissions may be eliminated and the energy consumption may decrease significantly. Porous carbon anodes made from different graphite grades were studied in controlled laboratory experiments. The anode potential, the anode carbon consumption and the level of HF gas above the electrolyte were measured during electrolysis. In some cases it was found that the methane oxidation was effectively participating in the anode process.

  17. Electrochemical degradation of bisphenol A on different anodes.

    Science.gov (United States)

    Cui, Yu-hong; Li, Xiao-yan; Chen, Guohua

    2009-04-01

    Laboratory experiments were carried out on the kinetics, pathways and mechanisms of electrochemical (EC) degradation of bisphenol A (BPA) on four types of anodes, Ti/boron-doped diamond (BDD), Ti/Sb-SnO(2), Ti/RuO(2) and Pt. There were considerable differences among the anodes in their effectiveness and performance of BPA electrolysis. BPA was readily destructed at the Ti/Sb-SnO(2) and Ti/BDD anodes, the Pt anode had a moderate ability to remove BPA, and the Ti/RuO(2) anode was incapable of effectively oxidising BPA. The intermediate products of EC degradation of BPA were detected and quantified by high-performance liquid chromatography (HPLC), and a general BPA degradation pathway was proposed based on the analytical results. It was suggested that OH radicals produced by water electrolysis attacked BPA to form hydroxylated BPA derivatives that were then transformed into one-ring aromatic compounds. These compounds underwent ring breakage, which led to the formation of aliphatic acids that were eventually mineralised by electrolysis to CO(2). Compared to the Pt and Ti/RuO(2) anodes, the Ti/Sb-SnO(2) and Ti/BDD anodes were found to have higher oxygen evolution potentials and higher anodic potentials for BPA electrolysis under the same current condition. However, the stability and durability of the Ti/Sb-SnO(2) anode still needs to be greatly improved for actual application. In comparison, with its high durability and good reactivity for organic oxidation, the Ti/BDD anode appears to be the more promising one for the effective EC treatment of BPA and similar endocrine disrupting chemical (EDC) pollutants.

  18. Three-dimensional metal scaffold supported bicontinuous silicon battery anodes.

    Science.gov (United States)

    Zhang, Huigang; Braun, Paul V

    2012-06-13

    Silicon-based lithium ion battery anodes are attracting significant attention because of silicon's exceptionally high lithium capacity. However, silicon's large volume change during cycling generally leads to anode pulverization unless the silicon is dispersed throughout a matrix in nanoparticulate form. Because pulverization results in a loss of electric connectivity, the reversible capacity of most silicon anodes dramatically decays within a few cycles. Here we report a three-dimensional (3D) bicontinuous silicon anode formed by depositing a layer of silicon on the surface of a colloidal crystal templated porous nickel metal scaffold, which maintains electrical connectivity during cycling due to the scaffold. The porous metal framework serves to both impart electrical conductivity to the anode and accommodate the large volume change of silicon upon lithiation and delithiation. The initial capacity of the bicontinuous silicon anode is 3568 (silicon basis) and 1450 mAh g(-1) (including the metal framework) at 0.05C. After 100 cycles at 0.3C, 85% of the capacity remains. Compared to a foil-supported silicon film, the 3D bicontinuous silicon anode exhibits significantly improved mechanical stability and cycleability.

  19. On self-sustainment of DC discharges with gridded anode

    Science.gov (United States)

    Yuan, Chengxun; Yao, Jingfeng; Eliseev, S. I.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang

    2017-10-01

    The paper presents results of numerical investigation of a large-volume plasma source based on a DC discharge with gridded anode. Geometry and configuration of the electrodes were chosen so as to ensure the formation of a cathode sheath, which would accelerate electrons up to high energies and inject them into the post-anode space and create plasma. Simulations were carried out using a hybrid model, and distributions of the main discharge parameters were obtained in a wide range of currents. At low currents, cathode sheath occupies whole interelectrode gap while plasma is formed in the post-anode space. It is shown that ions moving through the anode grid into the interelectrode gap cause reduction of discharge voltage when compared to the case of classical obstructed discharge with virtually closed anode grid. At higher currents, however, plasma is formed within the interlectrode gap as well, and ions moving from plasma in the post-anode space become trapped by reversed electric field. This essentially nullifies influence of the post-anode plasma on discharge properties.

  20. Effects of Charcoal Addition on the Properties of Carbon Anodes

    Directory of Open Access Journals (Sweden)

    Asem Hussein

    2017-03-01

    Full Text Available Wood charcoal is an attractive alternative to petroleum coke in production of carbon anodes for the aluminum smelting process. Calcined petroleum coke is the major component in the anode recipe and its consumption results in a direct greenhouse gas (GHG footprint for the industry. Charcoal, on the other hand, is considered as a green and abundant source of sulfur-free carbon. However, its amorphous carbon structure and high contents of alkali and alkaline earth metals (e.g., Na and Ca make charcoal highly reactive to air and CO2. Acid washing and heat treatment were employed in order to reduce the reactivity of charcoal. The pre-treated charcoal was used to substitute up to 10% of coke in the anode recipe in an attempt to investigate the effect of this substitution on final anode properties. The results showed deterioration in the anode properties by increasing the charcoal content. However, by adjusting the anode recipe, this negative effect can be considerably mitigated. Increasing the pitch content was found to be helpful to improve the physical properties of the anodes containing charcoal.

  1. The mineralogical characterization of tellurium in copper anodes

    Science.gov (United States)

    Chen, T. T.; Dutrizac, J. E.

    1993-12-01

    A mineralogical study of a «normal» commercial copper anode and six tellurium-rich copper anodes from the CCR Refinery of the Noranda Copper Smelting and Refining Company was carried out to identify the tellurium carriers and their relative abundances. In all the anodes, the major tellurium carrier is the Cu2Se-Cu2Te phase which occurs as a constituent of complex inclusions at the copper grain boundaries. In tellurium-rich anodes, the molar tellurium content of the Cu2Se-Cu2Te phase can exceed that of selenium. Although >85 pct of the tellurium occurs as the Cu2Se-Cu2Te phase, minor amounts are present in Cu-Pb-As-Bi-Sb oxide, Cu-Bi-As oxide, and Cu-Te-As oxide phases which form part of the grain-boundary inclusions. About 1 pct of the tellurium content of silver-rich anodes occurs in various silver alloys, but gold tellurides were never detected. Surprising is the fact that 2 to 8 pct of the total tellurium content of the anodes occurs in solid solution in the copper-metal matrix, and presumably, this form of tellurium dissolves at the anode interface during electrorefining.

  2. Inert Anode Life in Low Temperature Reduction Process

    Energy Technology Data Exchange (ETDEWEB)

    Bradford, Donald R.

    2005-06-30

    The production of aluminum metal by low temperature electrolysis utilizing metal non-consumable anodes and ceramic cathodes was extensively investigated. Tests were performed with traditional sodium fluoride--aluminum fluoride composition electrolytes, potassium fluoride-- aluminum fluoride electrolytes, and potassium fluoride--sodium fluoride--aluminum fluoride electrolytes. All of the Essential First-Tier Requirements of the joint DOE-Aluminum Industry Inert Anode Road Map were achieved and those items yet to be resolved for commercialization of this technology were identified. Methods for the fabrication and welding of metal alloy anodes were developed and tested. The potential savings of energy and energy costs were determined and potential environmental benefits verified.

  3. Na-Ion Battery Anodes: Materials and Electrochemistry.

    Science.gov (United States)

    Luo, Wei; Shen, Fei; Bommier, Clement; Zhu, Hongli; Ji, Xiulei; Hu, Liangbing

    2016-02-16

    The intermittent nature of renewable energy sources, such as solar and wind, calls for sustainable electrical energy storage (EES) technologies for stationary applications. Li will be simply too rare for Li-ion batteries (LIBs) to be used for large-scale storage purposes. In contrast, Na-ion batteries (NIBs) are highly promising to meet the demand of grid-level storage because Na is truly earth abundant and ubiquitous around the globe. Furthermore, NIBs share a similar rocking-chair operation mechanism with LIBs, which potentially provides high reversibility and long cycling life. It would be most efficient to transfer knowledge learned on LIBs during the last three decades to the development of NIBs. Following this logic, rapid progress has been made in NIB cathode materials, where layered metal oxides and polyanionic compounds exhibit encouraging results. On the anode side, pure graphite as the standard anode for LIBs can only form NaC64 in NIBs if solvent co-intercalation does not occur due to the unfavorable thermodynamics. In fact, it was the utilization of a carbon anode in LIBs that enabled the commercial successes. Anodes of metal-ion batteries determine key characteristics, such as safety and cycling life; thus, it is indispensable to identify suitable anode materials for NIBs. In this Account, we review recent development on anode materials for NIBs. Due to the limited space, we will mainly discuss carbon-based and alloy-based anodes and highlight progress made in our groups in this field. We first present what is known about the failure mechanism of graphite anode in NIBs. We then go on to discuss studies on hard carbon anodes, alloy-type anodes, and organic anodes. Especially, the multiple functions of natural cellulose that is used as a low-cost carbon precursor for mass production and as a soft substrate for tin anodes are highlighted. The strategies of minimizing the surface area of carbon anodes for improving the first-cycle Coulombic efficiency are

  4. The effect of antimony presence in anodic copper on kinetics and mechanism of anodic dissolution and cathodic deposition of copper

    Directory of Open Access Journals (Sweden)

    Stanković Z.D.

    2008-01-01

    Full Text Available The influence of the presence of Sb atoms, as foreign metal atoms in anode copper, on kinetics, and, on the mechanism of anodic dissolution and cathodic deposition of copper in acidic sulfate solution has been investigated. The galvanostatic single-pulse method has been used. Results indicate that presence of Sb atoms in anode copper increase the exchange current density as determined from the Tafel analysis of the electrode reaction. It is attributed to the increase of the crystal lattice parameter determined from XRD analysis of the electrode material.

  5. Virus-enabled silicon anode for lithium-ion batteries.

    Science.gov (United States)

    Chen, Xilin; Gerasopoulos, Konstantinos; Guo, Juchen; Brown, Adam; Wang, Chunsheng; Ghodssi, Reza; Culver, James N

    2010-09-28

    A novel three-dimensional Tobacco mosaic virus assembled silicon anode is reported. This electrode combines genetically modified virus templates for the production of high aspect ratio nanofeatured surfaces with electroless deposition to produce an integrated nickel current collector followed by physical vapor deposition of a silicon layer to form a high capacity silicon anode. This composite silicon anode produced high capacities (3300 mAh/g), excellent charge-discharge cycling stability (0.20% loss per cycle at 1C), and consistent rate capabilities (46.4% at 4C) between 0 and 1.5 V. The biological templated nanocomposite electrode architecture displays a nearly 10-fold increase in capacity over currently available graphite anodes with remarkable cycling stability.

  6. Excitation of anodized alumina films with a light source

    DEFF Research Database (Denmark)

    Aggerbeck, Martin; Canulescu, Stela; Rechendorff, K.

    Optical properties of anodized aluminium alloys were determined by optical diffuse reflectance spectroscopy of such films. Samples with different concentrations of dopants were excited with a white-light source combined with an integrating sphere for fast determination of diffuse reflectance....... The UV-VIS reflectance of Ti-doped anodized aluminium films was measured over the wavelength range of 200 nm to 900 nm. Titanium doped-anodized aluminium films with 5-15 wt% Ti were characterized. Changes in the diffuse light scattering of doped anodized aluminium films, and thus optical appearance......, with doping are discussed. Using the Kubelka-Munk model on the diffuse reflectance spectra of such films, the bandgap Eg of the oxide alloys can be determined....

  7. Silicon Whisker and Carbon Nanofiber Composite Anode, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) has successfully developed a silicon whisker and carbon nanofiber composite anode for lithium ion batteries on a Phase I program. PSI...

  8. Digital simulation of anodic stripping voltammetry from thin film electrodes

    International Nuclear Information System (INIS)

    Magallanes, J.F.

    1984-01-01

    The anodic stripping voltammetry (ASV) is routinely applied to control of Cu(II) in heavy water in the primary cooling loop of the Nuclear Power Reactor. The anodic stripping voltammetry (ASV) is a very well-known technique in electroanalytical chemistry. However, due to the complexity of the phenomena, it is practised with the fundamentals of empiric considerations. A geometric model for the anodic stripping voltammetry (ASV) from thin film electrodes which can be calculated by explicit digital simulation method is proposed as a possibility of solving the electrochemically reversible, cuasi-reversible and irreversible reactions under linear potential scan and multiple potential scans. (Until now the analytical mathematical method was applied to reversible reactions). All the results are compared with analytical solutions and experimental results and it permits to conclude that the anodic stripping voltammetry (ASV) can be studied with the simplicity and potentialities of explicit digital simulation methods. (M.E.L.) [es

  9. Scanning Anode Field Emission Characterisation of Carbon Nanotube emitter arrays

    NARCIS (Netherlands)

    Berhanu, S.; Gröning, O.; Chen, Z.; Merikhi, J.; Bachmann, P.K.

    2011-01-01

    Scanning anode field emission microscopy (SAFEM) was used to characterise carbon nanotube (CNT) emitter arrays produced within Philips CediX-Technotubes' activities. Four different samples were investigated and compared. The field enhancement distributions were determined and the local field

  10. Determining localized anode condition to maintain effective corrosion protection.

    Science.gov (United States)

    2010-01-01

    Thermal sprayed zinc anodes used for impressed current cathodic protection of reinforced concrete deteriorate over time. : Two different technologies, ultrasound and electrical circuit resistance combined with water permeability, were : investigated ...

  11. Blue fluorescent organic light emitting diodes with multilayered graphene anode

    International Nuclear Information System (INIS)

    Hwang, Joohyun; Choi, Hong Kyw; Moon, Jaehyun; Shin, Jin-Wook; Joo, Chul Woong; Han, Jun-Han; Cho, Doo-Hee; Huh, Jin Woo; Choi, Sung-Yool; Lee, Jeong-Ik; Chu, Hye Yong

    2012-01-01

    As an innovative anode for organic light emitting devices (OLEDs), we have investigated graphene films. Graphene has importance due to its huge potential in flexible OLED applications. In this work, graphene films have been catalytically grown and transferred to the glass substrate for OLED fabrications. We have successfully fabricated 2 mm × 2 mm device area blue fluorescent OLEDs with graphene anodes which showed 2.1% of external quantum efficiency at 1000 cd/m 2 . This is the highest value reported among fluorescent OLEDs using graphene anodes. Oxygen plasma treatment on graphene has been found to improve hole injections in low voltage regime, which has been interpreted as oxygen plasma induced work function modification. However, plasma treatment also increases the sheet resistance of graphene, limiting the maximum luminance. In summary, our works demonstrate the practical possibility of graphene as an anode material for OLEDs and suggest a processing route which can be applied to various graphene related devices.

  12. Nanocomposite anode materials for sodium-ion batteries

    Science.gov (United States)

    Manthiram, Arumugam; Kim Il, Tae; Allcorn, Eric

    2016-06-14

    The disclosure relates to an anode material for a sodium-ion battery having the general formula AO.sub.x--C or AC.sub.x--C, where A is aluminum (Al), magnesium (Mg), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), zirconium (Zr), molybdenum (Mo), tungsten (W), niobium (Nb), tantalum (Ta), silicon (Si), or any combinations thereof. The anode material also contains an electrochemically active nanoparticles within the matrix. The nanoparticle may react with sodium ion (Na.sup.+) when placed in the anode of a sodium-ion battery. In more specific embodiments, the anode material may have the general formula M.sub.ySb-M'O.sub.x--C, Sb-MO.sub.x--C, M.sub.ySn-M'C.sub.x--C, or Sn-MC.sub.x--C. The disclosure also relates to rechargeable sodium-ion batteries containing these materials and methods of making these materials.

  13. Trends in Catalytic Activity for SOFC Anode materials

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Bessler, W. G.

    2008-01-01

    Quantum mechanical calculations on the level of density-functional theory are used to calculate the stability of surface-adsorbed hydrogen atoms, oxygen atoms, and hydroxyl radicals for a variety of metals (Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Pt, Au) that may be used as electrode materials...... for solid oxide fuel cell (SOFC) anodes. The reaction energies along the hydrogen oxidation pathway were quantified for both, oxygen spillover and hydrogen spillover mechanisms at the three-phase boundary. The ab initio results are compared to previously-obtained experimental anode activities measured...... for nine different metal/stabilized zirconia anodes. The experimentally-observed variation of electrode activity with anode material is well-correlated with the calculated stability of surface-adsorbed atomic oxygen, but uncorrelated with the stability of surface-adsorbed hydrogen. This finding indicates...

  14. High-performance lithium battery anodes using silicon nanowires.

    Science.gov (United States)

    Chan, Candace K; Peng, Hailin; Liu, Gao; McIlwrath, Kevin; Zhang, Xiao Feng; Huggins, Robert A; Cui, Yi

    2008-01-01

    There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

  15. Hollow Nanostructured Anode Materials for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2010-01-01

    Full Text Available Abstract Hollow nanostructured anode materials lie at the heart of research relating to Li-ion batteries, which require high capacity, high rate capability, and high safety. The higher capacity and higher rate capability for hollow nanostructured anode materials than that for the bulk counterparts can be attributed to their higher surface area, shorter path length for Li+ transport, and more freedom for volume change, which can reduce the overpotential and allow better reaction kinetics at the electrode surface. In this article, we review recent research activities on hollow nanostructured anode materials for Li-ion batteries, including carbon materials, metals, metal oxides, and their hybrid materials. The major goal of this review is to highlight some recent progresses in using these hollow nanomaterials as anode materials to develop Li-ion batteries with high capacity, high rate capability, and excellent cycling stability.

  16. Stainless steel anodes for alkaline water electrolysis and methods of making

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  17. Enhanced anodic Ru(bpy)32+ electrogenerated chemiluminescence by polyphenols

    International Nuclear Information System (INIS)

    Lei Rong; Xu Xiao; Xu Da; Zhu Gang; Li Na; Liu Huwei; Li Kean

    2008-01-01

    Anodic Ru(bpy) 3 2+ electrogenerated chemiluminescence (ECL) can be enhanced by polyphenols in alkaline solution. Spin trapping-electron spin resonance (ESR) experiments verified that reactive oxygen species (ROS) were generated during the electrolysis of Ru(bpy) 3 2+ in alkaline solution, and oxidation of quercetin enhanced Ru(bpy) 3 2+ ECL at anodic potential by producing additional ROS. This ECL enhancement can be used to analyze real sample and evaluate antioxidant activity of polyphenols

  18. Note: Anodic bonding with cooling of heat-sensitive areas

    DEFF Research Database (Denmark)

    Vesborg, Peter Christian Kjærgaard; Olsen, Jakob Lind; Henriksen, Toke Riishøj

    2010-01-01

    Anodic bonding of silicon to glass always involves heating the glass and device to high temperatures so that cations become mobile in the electric field. We present a simple way of bonding thin silicon samples to borosilicate glass by means of heating from the glass side while locally cooling heat......-sensitive areas from the silicon side. Despite the high thermal conductivity of silicon, this method allows a strong anodic bond to form just millimeters away from areas essentially at room temperature....

  19. A Study on the Anodic Dissolution of Aluminum(II)

    International Nuclear Information System (INIS)

    Nam, C. W.; Park, C. S.; Park, C. S.

    1978-01-01

    In many cases oxide films formed on metals in atmosphere or aqueous solution are chemically inactive, especially it is the case with aluminum. In this study, anodic dissolution of aluminum was done using various electrolyte and cathode, mechanism of which was examined. As a consequence, oxide film on aluminum surface was dissolved together with the dissolution reaction of metal by the anodic current. It was shown that the dissolution reaction due to the contact between electrolyte and metal happened in the same time

  20. Hollow Nanostructured Anode Materials for Li-Ion Batteries

    OpenAIRE

    Liu Jun; Xue Dongfeng

    2010-01-01

    Abstract Hollow nanostructured anode materials lie at the heart of research relating to Li-ion batteries, which require high capacity, high rate capability, and high safety. The higher capacity and higher rate capability for hollow nanostructured anode materials than that for the bulk counterparts can be attributed to their higher surface area, shorter path length for Li+ transport, and more freedom for volume change, which can reduce the overpotential and allow better reaction kinetics at th...

  1. Optimal Conditions for Fast Charging and Long Cycling Stability of Silicon Microwire Anodes for Lithium Ion Batteries, and Comparison with the Performance of Other Si Anode Concepts

    Directory of Open Access Journals (Sweden)

    Enrique Quiroga-González

    2013-10-01

    Full Text Available Cycling tests under various conditions have been performed for lithium ion battery anodes made from free-standing silicon microwires embedded at one end in a copper current collector. Optimum charging/discharging conditions have been found for which the anode shows negligible fading (< 0.001% over 80 cycles; an outstanding result for this kind of anodes. Several performance parameters of the anode have been compared to the ones of other Si anode concepts, showing that especially the capacity as well as the rates of charge flow per nominal area of anode are the highest for the present anode. With regard to applications, the specific parameters per area are more important than the specific gravimetric parameters like the gravimetric capacity, which is good for comparing the capacity between materials but not enough for comparing between anodes.

  2. Microbial community composition is unaffected by anode potential

    KAUST Repository

    Zhu, Xiuping

    2014-01-21

    There is great controversy on how different set anode potentials affect the performance of a bioelectrochemical system (BES). It is often reported that more positive potentials improve acclimation and performance of exoelectrogenic biofilms, and alter microbial community structure, while in other studies relatively more negative potentials were needed to achieve higher current densities. To address this issue, the biomass, electroactivity, and community structure of anodic biofilms were examined over a wide range of set anode potentials (-0.25, -0.09, 0.21, 0.51, and 0.81 V vs a standard hydrogen electrode, SHE) in single-chamber microbial electrolysis cells. Maximum currents produced using a wastewater inoculum increased with anode potentials in the range of -0.25 to 0.21 V, but decreased at 0.51 and 0.81 V. The maximum currents were positively correlated with increasing biofilm biomass. Pyrosequencing indicated biofilm communities were all similar and dominated by bacteria most similar to Geobacter sulfurreducens. Differences in anode performance with various set potentials suggest that the exoelectrogenic communities self-regulate their exocellular electron transfer pathways to adapt to different anode potentials. © 2013 American Chemical Society.

  3. Nanostructured silicon anodes for lithium ion rechargeable batteries.

    Science.gov (United States)

    Teki, Ranganath; Datta, Moni K; Krishnan, Rahul; Parker, Thomas C; Lu, Toh-Ming; Kumta, Prashant N; Koratkar, Nikhil

    2009-10-01

    Rechargeable lithium ion batteries are integral to today's information-rich, mobile society. Currently they are one of the most popular types of battery used in portable electronics because of their high energy density and flexible design. Despite their increasing use at the present time, there is great continued commercial interest in developing new and improved electrode materials for lithium ion batteries that would lead to dramatically higher energy capacity and longer cycle life. Silicon is one of the most promising anode materials because it has the highest known theoretical charge capacity and is the second most abundant element on earth. However, silicon anodes have limited applications because of the huge volume change associated with the insertion and extraction of lithium. This causes cracking and pulverization of the anode, which leads to a loss of electrical contact and eventual fading of capacity. Nanostructured silicon anodes, as compared to the previously tested silicon film anodes, can help overcome the above issues. As arrays of silicon nanowires or nanorods, which help accommodate the volume changes, or as nanoscale compliant layers, which increase the stress resilience of silicon films, nanoengineered silicon anodes show potential to enable a new generation of lithium ion batteries with significantly higher reversible charge capacity and longer cycle life.

  4. Copper anode corrosion affects power generation in microbial fuel cells

    KAUST Repository

    Zhu, Xiuping

    2013-07-16

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  5. Process for anodizing a robotic device

    Science.gov (United States)

    Townsend, William T [Weston, MA

    2011-11-08

    A robotic device has a base and at least one finger having at least two links that are connected in series on rotary joints with at least two degrees of freedom. A brushless motor and an associated controller are located at each joint to produce a rotational movement of a link. Wires for electrical power and communication serially connect the controllers in a distributed control network. A network operating controller coordinates the operation of the network, including power distribution. At least one, but more typically two to five, wires interconnect all the controllers through one or more joints. Motor sensors and external world sensors monitor operating parameters of the robotic hand. The electrical signal output of the sensors can be input anywhere on the distributed control network. V-grooves on the robotic hand locate objects precisely and assist in gripping. The hand is sealed, immersible and has electrical connections through the rotary joints for anodizing in a single dunk without masking. In various forms, this intelligent, self-contained, dexterous hand, or combinations of such hands, can perform a wide variety of object gripping and manipulating tasks, as well as locomotion and combinations of locomotion and gripping.

  6. Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

    Science.gov (United States)

    Amrani, Salah

    La fabrication de l'aluminium est realisee dans une cellule d'electrolyse, et cette operation utilise des anodes en carbone. L'evaluation de la qualite de ces anodes reste indispensable avant leur utilisation. La presence des fissures dans les anodes provoque une perturbation du procede l'electrolyse et une diminution de sa performance. Ce projet a ete entrepris pour determiner l'impact des differents parametres de procedes de fabrication des anodes sur la fissuration des anodes denses. Ces parametres incluent ceux de la fabrication des anodes crues, des proprietes des matieres premieres et de la cuisson. Une recherche bibliographique a ete effectuee sur tous les aspects de la fissuration des anodes en carbone pour compiler les travaux anterieurs. Une methodologie detaillee a ete mise au point pour faciliter le deroulement des travaux et atteindre les objectifs vises. La majorite de ce document est reservee pour la discussion des resultats obtenus au laboratoire de l'UQAC et au niveau industriel. Concernant les etudes realisees a l'UQAC, une partie des travaux experimentaux est reservee a la recherche des differents mecanismes de fissuration dans les anodes denses utilisees dans l'industrie d'aluminium. L'approche etait d'abord basee sur la caracterisation qualitative du mecanisme de la fissuration en surface et en profondeur. Puis, une caracterisation quantitative a ete realisee pour la determination de la distribution de la largeur de la fissure sur toute sa longueur, ainsi que le pourcentage de sa surface par rapport a la surface totale de l'echantillon. Cette etude a ete realisee par le biais de la technique d'analyse d'image utilisee pour caracteriser la fissuration d'un echantillon d'anode cuite. L'analyse surfacique et en profondeur de cet echantillon a permis de voir clairement la formation des fissures sur une grande partie de la surface analysee. L'autre partie des travaux est basee sur la caracterisation des defauts dans des echantillons d'anodes crues

  7. Electrochemical characterization of anode passivation mechanisms in copper electrorefining

    Science.gov (United States)

    Moats, Michael Scott

    Anode passivation can decrease productivity and quality while increasing costs in modern copper electrorefineries. This investigation utilized electrochemical techniques to characterize the passivation behavior of anode samples from ten different operating companies. It is believed that this collection of anodes is the most diverse set ever to be assembled to study the effect of anode composition on passivation. Chronopotentiometry was the main electrochemical technique, employing a current density of 3820 A m-2. From statistical analysis of the passivation characteristics, increasing selenium, tellurium, silver, lead and nickel were shown to accelerate passivation. Arsenic was the only anode impurity that inhibited passivation. Oxygen was shown to accelerate passivation when increased from 500 to 1500 ppm, but further increases did not adversely affect passivation. Nine electrolyte variables were also examined. Increasing the copper, sulfuric acid or sulfate concentration of the electrolyte accelerated passivation. Arsenic in the electrolyte had no effect on passivation. Chloride and optimal concentrations of thiourea and glue delayed passivation. Linear sweep voltammetry, cyclic voltammetry, and impedance spectroscopy provided complementary information. Analysis of the electrochemical results led to the development of a unified passivation mechanism. Anode passivation results from the formation of inhibiting films. Careful examination of the potential details, especially those found in the oscillations just prior to passivation, demonstrated the importance of slimes, copper sulfate and copper oxide. Slimes confine dissolution to their pores and inhibit diffusion. This can lead to copper sulfate precipitation, which blocks more of the surface area. Copper oxide forms because of the resulting increase in potential at the interface between the copper sulfate and anode. Ultimate passivation occurs when the anode potential is high enough to stabilize the oxide film in

  8. Electrochemically anodized porous silicon: Towards simple and affordable anode material for Li-ion batteries.

    Science.gov (United States)

    Ikonen, T; Nissinen, T; Pohjalainen, E; Sorsa, O; Kallio, T; Lehto, V-P

    2017-08-11

    Silicon is being increasingly studied as the next-generation anode material for Li-ion batteries because of its ten times higher gravimetric capacity compared with the widely-used graphite. While nanoparticles and other nanostructured silicon materials often exhibit good cyclability, their volumetric capacity tends to be worse or similar than that of graphite. Furthermore, these materials are commonly complicated and expensive to produce. An effortless way to produce nanostructured silicon is electrochemical anodization. However, there is no systematic study how various material properties affect its performance in LIBs. In the present study, the effects of particle size, surface passivation and boron doping degree were evaluated for the mesoporous silicon with relatively low porosity of 50%. This porosity value was estimated to be the lowest value for the silicon material that still can accommodate the substantial volume change during the charge/discharge cycling. The optimal particle size was between 10-20 µm, the carbide layer enhanced the rate capability by improving the lithiation kinetics, and higher levels of boron doping were beneficial for obtaining higher specific capacity at lower rates. Comparison of pristine and cycled electrodes revealed the loss of electrical contact and electrolyte decay to be the major contributors to the capacity decay.

  9. Advances of the research evolution on aluminum electrochemical anodic oxidation technology

    Science.gov (United States)

    Yang, Z. B.; Hu, J. C.; Li, K. Q.; Zhang, S. Y.; Fan, Q. H.; Liu, S. A.

    2017-12-01

    This article gives an overview on the development of aluminum anodization technique in terms of fundamental aspects and practical applications in the past decades. Besides, the formation mechanism and structural characteristics of anodic alumina films as well as the factors affected the formation of porous anodic alumina films are also discussed. Anodic aluminum oxide (AAO) prepared by the anodization method can be divided into two categories: dense anodic alumina (DAA) and porous anodic alumina (PAA). This article also summarizes the optical properties, magnetic properties, solar absorption properties, and catalytic properties of porous anodic alumina film and its applications in nanomaterials, optical materials, magnetic materials, biosensors, solar cells, and so on. In addition, future developmental trend of porous anodic alumina film is covered.

  10. Alternative Anodes for the Electrolytic Reduction of Uranium Dioxide

    Science.gov (United States)

    Merwin, Augustus

    Reprocessing of spent nuclear fuel is an essential step in closing the nuclear fuel cycle. In order to consume current stockpiles, ceramic uranium dioxide spent nuclear fuel will be subjected to an electrolytic reduction process. The current reduction process employs a platinum anode and a stainless steel alloy 316 cathode in a molten salt bath consisting of LiCl-2wt% Li 2O and occurs at 700°C. A major shortcoming of the existing process is the degradation of the platinum anode under the severely oxidizing conditions encountered during electrolytic reduction. This work investigates alternative anode materials for the electrolytic reduction of uranium oxide. The high temperature and extreme oxidizing conditions encountered in these studies necessitated a unique set of design constraints on the system. Thus, a customized experimental apparatus was designed and constructed. The electrochemical experiments were performed in an electrochemical reactor placed inside a furnace. This entire setup was housed inside a glove box, in order to maintain an inert atmosphere. This study investigates alternative anode materials through accelerated corrosion testing. Surface morphology was studied using scanning electron microscopy. Surface chemistry was characterized using energy dispersive spectroscopy and Raman spectroscopy. Electrochemical behavior of candidate materials was evaluated using potentiodynamic polarization characteristics. After narrowing the number of candidate electrode materials, ferrous stainless steel alloy 316, nickel based Inconel 718 and elemental tungsten were chosen for further investigation. Of these materials only tungsten was found to be sufficiently stable at the anodic potential required for electrolysis of uranium dioxide in molten salt. The tungsten anode and stainless steel alloy 316 cathode electrode system was studied at the required reduction potential for UO2 with varying lithium oxide concentrations. Electrochemical impedance spectroscopy

  11. Low cost fuel cell diffusion layer configured for optimized anode water management

    Science.gov (United States)

    Owejan, Jon P; Nicotera, Paul D; Mench, Matthew M; Evans, Robert E

    2013-08-27

    A fuel cell comprises a cathode gas diffusion layer, a cathode catalyst layer, an anode gas diffusion layer, an anode catalyst layer and an electrolyte. The diffusion resistance of the anode gas diffusion layer when operated with anode fuel is higher than the diffusion resistance of the cathode gas diffusion layer. The anode gas diffusion layer may comprise filler particles having in-plane platelet geometries and be made of lower cost materials and manufacturing processes than currently available commercial carbon fiber substrates. The diffusion resistance difference between the anode gas diffusion layer and the cathode gas diffusion layer may allow for passive water balance control.

  12. Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Segura, Sergi, E-mail: sergigarcia@ub.edu [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Keller, Jürg [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Brillas, Enric [Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Radjenovic, Jelena, E-mail: j.radjenovic@awmc.uq.edu.au [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia)

    2015-02-11

    Graphical abstract: - Highlights: • Mineralization of secondary effluent by anodic oxidation with BDD anode. • Complete removal of 29 pharmaceuticals and pesticides at trace level concentrations. • Organochlorine and organobromine byproducts were formed at low μM concentrations. • Chlorine species evolution assessed to evaluate the anodic oxidation applicability. - Abstract: Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl{sup −} ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl{sub 2}/HClO/ClO{sup −}), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO{sup −} species led to the production of ClO{sub 3}{sup −} and ClO{sub 4}{sup −} ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment.

  13. Plant-scale anodic dissolution of unirradiated IFR fuel pins

    International Nuclear Information System (INIS)

    Gay, E.C.; Tomczuk, Z.; Miller, W.E.

    1993-01-01

    This report discusses anodic dissolution which is a major operation in the pyrometallurgical process for recycling spent metal fuels from the Integral Fast Reactor (IFR), an advanced reactor design developed at Argonne National Laboratory. This process involves electrorefining the heavy metals (uranium and plutonium) from chopped, steel-clad fuel segments. The heavy metals are electrotransported from anodic dissolution baskets to solid and liquid cathodes in a molten salt electrolyte (LiCl-KCI) at 500 degrees C. Uranium is recovered on a solid cathode mandrel, while a uranium-plutonium mixture is recovered in a liquid cadmium cathode. The anode configuration consists of four baskets mounted on an anode shaft. These baskets provide parallel circuits in the electrolyte and salt flow through the chopped fuelbed as the baskets are rotated. The baskets for the engineering-scale tests were sized to contain up to 2.5 kg of heavy metal. Anodic dissolution of 10 kg batches of chopped, steel-clad simulated tuel (U-10% Zr and U-Zr-Fs alloy) was demonstrated

  14. Theory and simulation of anode spots in low pressure plasmas

    Science.gov (United States)

    Scheiner, Brett; Barnat, Edward V.; Baalrud, Scott D.; Hopkins, Matthew M.; Yee, Benjamin T.

    2017-11-01

    When electrodes are biased above the plasma potential, electrons accelerated through the associated electron sheath can dramatically increase the ionization rate of neutrals near the electrode surface. It has previously been observed that if the ionization rate is great enough, a double layer separates a luminous high-potential plasma attached to the electrode surface (called an anode spot or fireball) from the bulk plasma. Here, results of the first 2D particle-in-cell simulations of anode spot formation are presented along with a theoretical model describing the formation process. It is found that ionization leads to the build-up of an ion-rich layer adjacent to the electrode, forming a narrow potential well near the electrode surface that traps electrons born from ionization. It is shown that anode spot onset occurs when a quasineutral region is established in the potential well and the density in this region becomes large enough to violate the steady-state Langmuir condition, which is a balance between electron and ion fluxes across the double layer. A model for steady-state properties of the anode spot is also presented, which predicts values for the anode spot size, double layer potential drop, and form of the sheath at the electrode by considering particle, power, and current balance. These predictions are found to be consistent with the presented simulation and previous experiments.

  15. Investigation of different anode materials for aluminium rechargeable batteries

    Science.gov (United States)

    Muñoz-Torrero, David; Leung, Puiki; García-Quismondo, Enrique; Ventosa, Edgar; Anderson, Marc; Palma, Jesús; Marcilla, Rebeca

    2018-01-01

    In order to shed some light into the importance of the anodic reaction in reversible aluminium batteries, we investigate here the electrodeposition of aluminium in an ionic liquid electrolyte (BMImCl-AlCl3) using different substrates. We explore the influence of the type of anodic material (aluminium, stainless steel and carbon) and its 3D geometry on the reversibility of the anodic reaction by cyclic voltammetry (CV) and galvanostatic charge-discharge. The shape of the CVs confirms that electrodeposition of aluminium was feasible in the three materials but the highest peak currents and smallest peak separation in the CV of the aluminium anode suggested that this material was the most promising. Interestingly, carbon-based substrates appeared as an interesting alternative due to the high peak currents in CV, moderate overpotentials and dual role as anode and cathode. 3D substrates such as fiber-based carbon paper and aluminium mesh showed significantly smaller overpotentials and higher efficiencies for Al reaction suggesting that the use of 3D substrates in full batteries might result in enhanced power. This is corroborated by polarization testing of full Al-batteries.

  16. An Investigation of the Role of Near-Anode Plasma Conditions on Anode Spot Self-Organization in Atmospheric Pressure DC Glows

    Science.gov (United States)

    Kovach, Yao; Foster, John

    2016-09-01

    In previous work, plasma self-organization patterns were experimentally observed on both liquid surface and metal anode surface in atmospheric pressure glows. However, the origin of the self-organized pattern formation is still poorly understood and is currently under study. In this work, it was observed that the discharge current is the dominant parameter controlling the onset of the self-organization of the plasma attachment on a liquid anode. On the other hand, it is observed that interelectrode spacing is the key parameter that controls plasma self-organization on metal anodes. Presented here are experiments aimed at understanding how these parameters control conditions at the anode surface which ultimately result in self-organization. Here we determine the effects of space charge at the anode surface and also estimate the anode fall voltage in response to discharge parameter variations. Additionally, electron microscopy is used to assess anode morphological changes resulting from the self-organization plasma attachments.

  17. Surface of Alumina Films after Prolonged Breakdowns in Galvanostatic Anodization

    Directory of Open Access Journals (Sweden)

    Christian Girginov

    2011-01-01

    Full Text Available Breakdown phenomena are investigated at continuous isothermal (20∘C and galvanostatic (0.2–5 mA cm−2 anodizing of aluminum in ammonium salicylate in dimethylformamide (1 M AS/DMF electrolyte. From the kinetic (-curves, the breakdown voltage ( values are estimated, as well as the frequency and amplitude of oscillations of formation voltage ( at different current densities. The surface of the aluminum specimens was studied using atomic force microscopy (AFM. Data on topography and surface roughness parameters of the electrode after electric breakdowns are obtained as a function of anodization time. The electrode surface of anodic films, formed with different current densities until the same charge density has passed (2.5 C cm−2, was assessed. Results are discussed on the basis of perceptions of avalanche mechanism of the breakdown phenomena, due to the injection of electrons and their multiplication in the volume of the film.

  18. Novel Non-Carbonate Based Electrolytes for Silicon Anodes

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ye [Wildcat Discovery Technologies, San Diego, CA (United States); Yang, Johnny [Wildcat Discovery Technologies, San Diego, CA (United States); Cheng, Gang [Wildcat Discovery Technologies, San Diego, CA (United States); Carroll, Kyler [Wildcat Discovery Technologies, San Diego, CA (United States); Clemons, Owen [Wildcat Discovery Technologies, San Diego, CA (United States); Strand, Diedre [Wildcat Discovery Technologies, San Diego, CA (United States)

    2016-09-09

    Substantial improvement in the energy density of rechargeable lithium batteries is required to meet the future needs for electric and plug-in electric vehicles (EV and PHEV). Present day lithium ion battery technology is based on shuttling lithium between graphitic carbon and inorganic oxides. Non-graphitic anodes, such as silicon can provide significant improvements in energy density but are currently limited in cycle life due to reactivity with the electrolyte. Wildcat/3M proposes the development of non-carbonate electrolyte formulations tailored for silicon alloy anodes. Combining these electrolytes with 3M’s anode and an NMC cathode will enable up to a 20% increase in the volumetric cell energy density, while still meeting the PHEV/EV cell level cycle/calendar life goals.

  19. Mixed conductor anodes: Ni as electrocatalyst for hydrogen conversion

    DEFF Research Database (Denmark)

    Primdahl, S.; Mogensen, Mogens Bjerg

    2002-01-01

    Five types of anodes for solid oxide fuel cells (SOFC) are examined on an yttria-stabilised zirconia (YSZ) electrolyte by impedance spectroscopy at 850 degreesC in hydrogen. The examined porous anodes are a Ni/Zr(0.92)Y(0.16)O(2.08) (Ni/YSZ) cermet, a Ni/Ce(0.9)Gd(0.1)O(1.95) (Ni/CGI) cermet, a Ce...... conductors (MIEC's), distinctly in the low-frequency part of the impedance spectra. An effect of isotope exchange (H(2)/H(2)O to D(2)/D(2)O) is observed for all anodes. The low-frequency limitation is suggested to be hydrogen adsorption and/or dissociation on the surface of MIEC electrodes, (C) 2002 Elsevier...

  20. Modified strontium titanates: From defect chemistry to SOFC anodes

    DEFF Research Database (Denmark)

    Verbraeken, M.C.; Ramos, Tania; Agersted, Karsten

    2015-01-01

    Modified strontium titanates have received much attention recently for their potential as anode material in solid oxide fuel cells (SOFC). Their inherent redox stability and superior tolerance to sulphur poisoning and coking as compared to Ni based cermet anodes could improve durability of SOFC...... systems dramatically. Various substitution strategies can be deployed to optimise materials properties in these strontium titanates, such as electronic conductivity, electrocatalytic activity, chemical stability and sinterability, and thus mechanical strength. Substitution strategies not only cover choice...... of modified strontium titanates, this paper reviews three different A-site deficient donor (La, Y, Nb) substituted strontium titanates for their electrical behaviour and fuel cell performance. Promising performances in both electrolyte as well as anode supported cell designs have been obtained, when using...

  1. Titanium nitride stamps replicating nanoporous anodic alumina films

    International Nuclear Information System (INIS)

    Navas, D; Sanchez, O; Asenjo, A; Jaafar, M; Baldonedo, J L; Vazquez, M; Hernandez-Velez, M

    2007-01-01

    Fabrication of nanostructured TiN films by magnetron sputtering using nanoporous anodic alumina films (NAAF) as substrates is reported. These hard nanostructured films could be used for pre-patterning aluminium foils and to obtain nanoporous films replicating the starting NAAF over a wide range of pore diameters and spacings. Pre-patterned Al foils are obtained by compression with pressures lower than those previously reported, then a new NAAF can be fabricated by means of only one anodization process. As an example, one of the TiN stamps was used for pre-patterning an Al foil at a pressure of 200 kg cm -2 and then it was anodized in oxalic acid solution obtaining the corresponding replica of the starting NAAF

  2. Aluminum as anode for energy storage and conversion: a review

    Science.gov (United States)

    Li, Qingfeng; Bjerrum, Niels J.

    Aluminum has long attracted attention as a potential battery anode because of its high theoretical voltage and specific energy. The protective oxide layer on the aluminum surface is however detrimental to the battery performance, contributing to failure to achieve the reversible potential and causing the delayed activation of the anode. By developing aluminum alloys as anodes and solution additives to electrolytes, a variety of aluminum batteries have been extensively investigated for various applications. From molten salt and other non-aqueous electrolytes, aluminum can be electrodeposited and therefore be suitable for developing rechargable batteries. Considerable efforts have been made to develop secondary aluminum batteries of high power density. In the present paper, these research activities are reviewed, including aqueous electrolyte primary batteries, aluminum-air batteries and molten salt secondary batteries.

  3. A new position sensitive anode for plasmas diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, R., E-mail: grasso@lns.infn.it [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, Catania 95123 (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, Catania 95125 (Italy); Tudisco, S. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, Catania 95123 (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, Catania 95125 (Italy); Anzalone, A. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, Catania 95123 (Italy); Musumeci, F.; Scordino, A. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, Catania 95123 (Italy); Dipartimento di Fisica ed Astronomia, Universita' di Catania, Viale A. Doria 6, Catania 95125 (Italy); Spitaleri, A. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, Catania 95123 (Italy); Anzalone, R.; D’Arrigo, G. [INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, Catania 95123 (Italy); IMM-Istituto per la Microelettronica e Microsistemi, CRN, VIII Strada 5 (Zona Industriale), Catania 95121 (Italy); LaVia, F. [IMM-Istituto per la Microelettronica e Microsistemi, CRN, VIII Strada 5 (Zona Industriale), Catania 95121 (Italy)

    2013-08-21

    The studies of plasmas generated by laser-matter interaction requires detectors that are able to perform the time resolved imaging of photons and charged particles. Such information are necessary in order to characterize the time evolution of fundamental parameters (as temperature, density, etc.) of plasma. One of the key elements of such diagnostics is the position sensitive anode. We are studying a new type of position-sensitive anode which will be realized by using silicon planar technology: a trapezes and stripes resistive anode (TSRA). The new TSRA is a two-dimensional system, which can be coupled with one of two-stage multichannel plates for the particles detection or for photons.

  4. Anodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain

    An important issue that has limited the potential of Solid Oxide Fuel Cells (SOFCs) for portable applications is its high operating temperatures (800-1000 ºC). Lowering the operating temperature of SOFCs to 400-600 ºC enable a wider material selection, reduced degradation and increased lifetime....... On the other hand, low-temperature operation poses serious challenges to the electrode performance. Effective catalysts, redox stable electrodes with improved microstructures are the prime requisite for the development of efficient SOFC anodes. The performance of Nb-doped SrT iO3 (STN) ceramic anodes...... at 400ºC. The potential of using WO3 ceramic as an alternative anode materials has been explored. The relatively high electrode polarization resistance obtained, 11 Ohm cm2 at 600 ºC, proved the inadequate catalytic activity of this system for hydrogen oxidation. At the end of this thesis...

  5. Energy transfer in porous anodic alumina/rhodamine 110 nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Elhouichet, H., E-mail: habib.elhouichet@fst.rnu.tn [Laboratoire de Physico-Chimie des Materiaux Mineraux et leurs Applications, Centre National de Recherches en Sciences des Materiaux, B.P. 95, Hammam-Lif 2050 (Tunisia); Departement de Physique, Faculte des Sciences de Tunis, University of Tunis Elmanar 2092 Tunis (Tunisia); Harima, N.; Koyama, H. [Hyogo University of Teacher Education, Kato, Hyogo 673-1494 (Japan); Gaponenko, N.V. [Belarusian State University of Informatics and Radioelectronics, P. Browki St. 6, 220013 Minsk (Belarus)

    2012-09-15

    We have used porous anodic alumina (PAA) films as templates for embedding rhodamine 110 (Rh110) molecules and examined their photoluminescence (PL) properties in detail. The analysis of the polarization memory (PM) of PL strongly suggests that there is a significant energy transfer from PAA to Rh110 molecules. The effect of annealing the PAA layer on the PL properties of the nanocomposite has been studied. The results show that the energy transfer becomes more efficient in annealed PAA. - Highlights: Black-Right-Pointing-Pointer Porous anodic alumina-rhodamine 110 nanocomposites are elaborated. Black-Right-Pointing-Pointer Efficient energy transfer from the host to Rh110 molecules is evidenced from measurements of photoluminescence and degree of polarization memory spectra. Black-Right-Pointing-Pointer Thermal annealing of porous anodic alumina can improve the process of excitation transfer.

  6. Isotope investigation of anodic slime movements in copper electrorefining baths

    International Nuclear Information System (INIS)

    Urbanski, T.; Kohman, L.; Strzelecki, M.; Chojecki, M.; Kaczynska, R.; Wieclaw, B.

    1975-01-01

    A method was developed and introduced for monitoring the movement of silver-containing anodic slimes in copper electrorefining baths. Radioactive 111 Ag was used as tracer and copper plates labelled with the tracer were inserted into the anodes. During electrorefining the slime produced was continuously marked by the tracer. The activity of 111 Ag was measured at various points inside the bath by sampling and continuously registered with the aid of integrators. It was found that more than 99 percent of the slime slipped to the bottom of the bath close to the anode surface and did not migrate even at highest electrolyte flow rates. Small quantities of suspended slime contained an insignificant concentration of silver and should not be a source of cathode contamination. (author)

  7. Anode Improvement in Rechargeable Lithium-Sulfur Batteries.

    Science.gov (United States)

    Tao, Tao; Lu, Shengguo; Fan, Ye; Lei, Weiwei; Huang, Shaoming; Chen, Ying

    2017-12-01

    Owing to their theoretical energy density of 2600 Wh kg -1 , lithium-sulfur batteries represent a promising future energy storage device to power electric vehicles. However, the practical applications of lithium-sulfur batteries suffer from poor cycle life and low Coulombic efficiency, which is attributed, in part, to the polysulfide shuttle and Li dendrite formation. Suppressing Li dendrite growth, blocking the unfavorable reaction between soluble polysulfides and Li, and improving the safety of Li-S batteries have become very important for the development of high-performance lithium sulfur batteries. A comprehensive review of various strategies is presented for enhancing the stability of the anode of lithium sulfur batteries, including inserting an interlayer, modifying the separator and electrolytes, employing artificial protection layers, and alternative anodes to replace the Li metal anode. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Anodic oxidation of InP in pure water

    International Nuclear Information System (INIS)

    Robach, Y.; Joseph, J.; Bergignat, E.; Hollinger, G.

    1989-01-01

    It is shown that thin InP native oxide films can be grown by anodization of InP in pure water. An interfacial phosphorus-rich In(PO 3 ) 3 -like condensed phosphate is obtained this way. This condensed phosphate has good passivating properties and can be used in electronic device technology. The chemical composition of these native oxides was found similar to that of an anodic oxide grown in an anodization in glycol and water (AGW) electrolyte. From the similarity between the two depth profiles observed in pure water and AGW electrolyte, they can conclude that dissolution phenomena do not seem to play a major role. The oxide growth seems to be controlled by the drift of ionic species under the electric field

  9. Improved Anode for a Direct Methanol Fuel Cell

    Science.gov (United States)

    Valdez, Thomas; Narayanan, Sekharipuram

    2005-01-01

    A modified chemical composition has been devised to improve the performance of the anode of a direct methanol fuel cell. The main feature of the modified composition is the incorporation of hydrous ruthenium oxide into the anode structure. This modification can reduce the internal electrical resistance of the cell and increase the degree of utilization of the anode catalyst. As a result, a higher anode current density can be sustained with a smaller amount of anode catalyst. These improvements can translate into a smaller fuel-cell system and higher efficiency of conversion. Some background information is helpful for understanding the benefit afforded by the addition of hydrous ruthenium oxide. The anode of a direct methanol fuel cell sustains the electro-oxidation of methanol to carbon dioxide in the reaction CH3OH + H2O--->CO2 + 6H(+) + 6e(-). An electrocatalyst is needed to enable this reaction to occur. The catalyst that offers the highest activity is an alloy of approximately equal numbers of atoms of the noble metals platinum and ruthenium. The anode is made of a composite material that includes high-surface-area Pt/Ru alloy particles and a proton-conducting ionomeric material. This composite is usually deposited onto a polymer-electrolyte (proton-conducting) membrane and onto an anode gas-diffusion/current-collector sheet that is subsequently bonded to the proton-conducting membrane by hot pressing. Heretofore, the areal density of noble-metal catalyst typically needed for high performance has been about 8 mg/cm2. However, not all of the catalyst has been utilized in the catalyzed electro-oxidation reaction. Increasing the degree of utilization of the catalyst would make it possible to improve the performance of the cell for a given catalyst loading and/or reduce the catalyst loading (thereby reducing the cost of the cell). The use of carbon and possibly other electronic conductors in the catalyst layer has been proposed for increasing the utilization of the

  10. Composite anodes for lithium-ion batteries: status and trends

    Directory of Open Access Journals (Sweden)

    Christian M. Julien

    2016-07-01

    Full Text Available Presently, the negative electrodes of lithium-ion batteries (LIBs is constituted by carbon-based materials that exhibit a limited specific capacity 372 mAh g−1 associated with the cycle between C and LiC6. Therefore, many efforts are currently made towards the technological development nanostructured materials in which the electrochemical processes occurs as intercalation, alloying or conversion reactions with a good accommodation of dilatation/contraction during cycling. In this review, attention is focused on advanced anode composite materials based on carbon, silicon, germanium, tin, titanium and conversion anode composite based on transition-metal oxides.

  11. Cylindrical Three-Dimensional Porous Anodic Alumina Networks

    Directory of Open Access Journals (Sweden)

    Pedro M. Resende

    2016-11-01

    Full Text Available The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates.

  12. Planar metal-supported SOFC with novel cermet anode

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Hjelm, Johan; Klemensø, Trine

    2011-01-01

    Metal-supported solid oxide fuel cells are expected to offer several potential advantages over conventional anode (Ni-YSZ) supported cells. For example, increased resistance against mechanical and thermal stresses and a reduction in material costs. When Ni-YSZ based anodes are used in metal suppo...... and durability at a broad range of temperatures and is especially suitable for intermediate temperature operation at around 650°C. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  13. Tin-phosphate glass anode for sodium ion batteries

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Honma

    2013-11-01

    Full Text Available The electrochemical property of tin-phosphate (designate as GSPO glass anode for the sodium ion battery was studied. During the first charge process, sodium ion diffused into GSPO glass matrix and due to the reduction of Sn2+ to Sn0 state sodiated tin metal nano-size particles are formed in oxide glass matrix. After the second cycle, we confirmed the steady reversible reaction ∼320 mAh/g at 0–1 V cutoff voltage condition by alloying process in NaxSn4. The tin-phosphate glass is a promising candidate of new anode active material that realizes high energy density sodium ion batteries.

  14. Anodization and Optical Appearance of Sputter Deposited Al-Zr Coatings

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Canulescu, Stela; Shabadi, Rajashekhara

    2014-01-01

    Anodized Al alloy components are extensively used in various applications like architectural, decorative and automobiles for corrosion protection and/or decorative optical appearance. However, tailoring the anodized layer for specific optical appearance is limited due to variation in composition...

  15. Effects of sodium tartrate anodizing on fatigue life of TA15 titanium alloy

    Directory of Open Access Journals (Sweden)

    Fu Chunjuan

    2015-08-01

    Full Text Available Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy. The sodium tartrate anodizing is a new kind of environmental anodizing method. In this work, the effects of sodium tartrate anodizing on mechanical property were studied. The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former. The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared. The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life. While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.

  16. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  17. Microstructural evolution of nanograin nickel-zirconia cermet anode materials for solid oxide fuel cell applications

    International Nuclear Information System (INIS)

    Nayak, Bibhuti Bhusan

    2012-01-01

    The aim of the study is to study the structure, microstructure, porosity, thermal expansion, electrical conductivity and electrochemical behavior of the anode material thus synthesized in order to find its suitability for solid oxide fuel cell (SOFC) anode application

  18. Experimental Studies of Anode Sheath Phenomena in a Hall Thruster Discharge

    International Nuclear Information System (INIS)

    Dorf, L.; Raitses, Y.; Fisch, N.J.

    2004-01-01

    Both electron-repelling and electron-attracting anode sheaths in a Hall thruster were characterized by measuring the plasma potential with biased and emissive probes [L. Dorf, Y. Raitses, V. Semenov, and N.J. Fisch, Appl. Phys. Let. 84 (2004) 1070]. In the present work, two-dimensional structures of the plasma potential, electron temperature, and plasma density in the near-anode region of a Hall thruster with clean and dielectrically coated anodes are identified. Possible mechanisms of anode sheath formation in a Hall thruster are analyzed. The path for current closure to the anode appears to be the determining factor in the anode sheath formation process. The main conclusion of this work is that the anode sheath formation in Hall thrusters differs essentially from that in the other gas discharge devices, like a glow discharge or a hollow anode, because the Hall thruster utilizes long electron residence times to ionize rather than high neutral pressures

  19. Zinc sacrificial anode behavior at elevated temperatures in sodium chloride and tap water environments

    International Nuclear Information System (INIS)

    Othman, Othman Mohsen

    2005-01-01

    Zinc sacrificial anode coupled to mild steel was tested in sodium chloride and tap water environments at elevated temperatures. The anode failed to protect the mild steel specimens in tap water environment at all temperatures specified for this study. This was partly due to the high resistivity of the medium. The temperature factor did not help to activate the anode in water tap medium. In sodium chloride environment the anode demonstrated good protection for steel cathodes. In tap water environment the anode weight loss was negligible. The zinc anode suffered intergranular corrosion in sodium chloride environment and this was noticed starting at 40 degree centigrade. In tap water environment the zinc anode demonstrated interesting behavior beyond 60 degree centigrade, that could be attributed to the phenomenon of reversal of potential at elevated temperatures. It also showed shallow pitting spots in tap water environment without any sign of intergranular corrosion. Zinc anodes would suffer intergranular corrosion at high temperatures. (author)

  20. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  1. Solid state thin film battery having a high temperature lithium alloy anode

    Science.gov (United States)

    Hobson, David O.

    1998-01-01

    An improved rechargeable thin-film lithium battery involves the provision of a higher melting temperature lithium anode. Lithium is alloyed with a suitable solute element to elevate the melting point of the anode to withstand moderately elevated temperatures.

  2. Electrical Resistance Measurements and Microstructural Characterization of the Anode/Interconnect Contact in Simulated Anode-Side SOFC Conditions

    DEFF Research Database (Denmark)

    Harthøj, Anders; Alimadadi, Hossein; Holt, Tobias

    2015-01-01

    . The zone is austenitic at the exposure temperature but transforms to ferrite during cooling. When a CeO2 nickel diffusion barrier layer was used The ASR was considerably higher. These results imply that nickel diffusion is not only detrimental: It leads to microstructural instability but also results......Metallic interconnects in solid oxide fuel cell (SOFC) stacks are often in direct contact with a nickel/yttria stabilized zirconia (Ni/YSZ) cermet anode. Interdiffusion between the two components may occur at the operating temperature of 700–850◦C. The alteration of chemical composition can result...... anode conditions at 800◦C. The microstructure in the contact area was characterized using scanning electron microscopy techniques. The ASR was low for the steel in direct contact with the Ni/YSZ anode. Nickel diffusion into the steel resulted in a fine grained zone, which was identified as ferrite...

  3. 46 CFR 35.01-25 - Sacrificial anode installations-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... submitted for approval. The anode should be magnesium free and the silicon content limited to trace amounts... 46 Shipping 1 2010-10-01 2010-10-01 false Sacrificial anode installations-TB/ALL. 35.01-25 Section... Operating Requirements § 35.01-25 Sacrificial anode installations—TB/ALL. (a) The installation of magnesium...

  4. Influence of carbon anode properties on performance and microbiome of Microbial Electrolysis Cells operated on urine

    NARCIS (Netherlands)

    Barbosa, Sónia G.; Peixoto, Luciana; Soares, Olívia S.G.P.; Pereira, Manuel Fernando R.; Heijne, Annemiek Ter; Kuntke, Philipp; Alves, Maria Madalena; Pereira, Maria Alcina

    2018-01-01

    Anode performance of Microbial Electrolysis Cells (MECs) fed with urine using different anodes, Keynol (phenolic-based), C-Tex (cellulose-based) and PAN (polyacrylonitrile-based) was compared under cell potential control (1st assay) and anode potential control (2nd assay). In both assays, C-Tex MEC

  5. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  6. The effect of zinc on the aluminum anode of the aluminum-air battery

    Science.gov (United States)

    Tang, Yougen; Lu, Lingbin; Roesky, Herbert W.; Wang, Laiwen; Huang, Baiyun

    Aluminum is an ideal material for batteries, due to its excellent electrochemical performance. Herein, the effect of zinc on the aluminum anode of the aluminum-air battery, as an additive for aluminum alloy and electrolytes, has been studied. The results show that zinc can decrease the anodic polarization, restrain the hydrogen evolution and increase the anodic utilization rate.

  7. Structural micro-porous carbon anode for rechargeable lithium-ion batteries

    Science.gov (United States)

    Delnick, Frank M.; Even, Jr., William R.; Sylwester, Alan P.; Wang, James C. F.; Zifer, Thomas

    1995-01-01

    A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc.

  8. Prelithiated silicon nanowires as an anode for lithium ion batteries.

    Science.gov (United States)

    Liu, Nian; Hu, Liangbing; McDowell, Matthew T; Jackson, Ariel; Cui, Yi

    2011-08-23

    Silicon is one of the most promising anode materials for the next-generation high-energy lithium ion battery (LIB), while sulfur and some other lithium-free materials have recently shown high promise as cathode materials. To make a full battery out of them, either the cathode or the anode needs to be prelithiated. Here, we present a method for prelithiating a silicon nanowire (SiNW) anode by a facile self-discharge mechanism. Through a time dependence study, we found that 20 min of prelithiation loads ∼50% of the full capacity into the SiNWs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies show that the nanostructure of SiNWs is maintained after prelithiation. We constructed a full battery using our prelithiated SiNW anode with a sulfur cathode. Our work provides a protocol for pairing lithium-free electrodes to make the next-generation high-energy LIB. © 2011 American Chemical Society

  9. Optimization of the strength of SOFC anode supports

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Ramos, Tania; Faes, A.

    2012-01-01

    During operation solid oxide fuel cells are stressed by temperature gradients and various internal and external mechanical loads, which must be withstood. This work deals with the optimization of the strength of as-sintered anode supported half-cells by imposing changes to production parameters...... technology a mathematical frame to determine the optimal porosity of a SOFC system is presented....

  10. Nanostructured Anodic Multilayer Dielectric Stacked Metal-Insulator-Metal Capacitors.

    Science.gov (United States)

    Karthik, R; Kannadassan, D; Baghini, Maryam Shojaei; Mallick, P S

    2015-12-01

    This paper presents the fabrication of Al2O3/TiO2/Al2O3 metal-insulator-metal (MIM) capacitor using anodization technique. High capacitance density of > 3.5 fF/μm2, low quadratic voltage coefficient of capacitance of capacitor.

  11. Multichannel discharge between jet electrolyte cathode and jet electrolyte anode

    NARCIS (Netherlands)

    Shakirova, E. F.; Gaitsin, Al. F.; Son, E. E.

    We present the results of an experimental study of multichannel discharge between a jet electrolyte cathode and jet electrolyte anode within a wide range of parameters. We pioneer the reveal of the burning particularities and characteristics of multichannel discharge with jet electrolyte and droplet

  12. Spark protection layers for CMOS pixel anode chips in MPGDs

    NARCIS (Netherlands)

    Bilevych, Y.; Bilevych, Y.; Blanco Carballo, V.M.; Chefdeville, M.A.; Colas, P.; Delagnes, E.; Fransen, M.; van der Graaff, H.; Koppert, W.J.C.; Melai, J.; Salm, Cora; Schmitz, Jurriaan; Timmermans, J.; Timmermans, J.; Wyrsch, N.

    2011-01-01

    In this work we have investigated the functioning of high resistivity amorphous silicon and silicon-rich nitride layers as a protection against discharges in Micro-Patterned Gaseous Detectors (MPGDs).When the anode is protected by a high resistivity layer, discharge signals are limited in charge. A

  13. The corrosion protection of aluminum by various anodizing treatments

    Science.gov (United States)

    Danford, Merlin D.

    1989-01-01

    Corrosion protection to 6061-T6 aluminum, afforded by both teflon-impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5 percent NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved superior to that afforded by Polylube at each pH, with corrosion protection by the hard-anodized, water-sealed coat at pH 9.5 providing the best protection. Electrochemical work in each case was corroborated by microscopic examination of the coats after exposure. Corrosion protection by Tufram at pH 9.5 was most comparable to that of the hard-anodized samples, although pitting and some cracking of the coat did occur.

  14. Advanced anodes for high-temperature fuel cells

    DEFF Research Database (Denmark)

    Atkinson, A.; Barnett, S.; Gorte, R.J.

    2004-01-01

    or anode. In terms of mitigating global warming, the ability of the SOFC to use commonly available fuels at high efficiency, promises an effective and early reduction in carbon dioxide emissions, and hence is one of the lead new technologies for improving the environment. Here, we discuss recent...

  15. [Corrosion resistant properties of different anodized microtopographies on titanium surfaces].

    Science.gov (United States)

    Fangjun, Huo; Li, Xie; Xingye, Tong; Yueting, Wang; Weihua, Guo; Weidong, Tian

    2015-12-01

    To investigate the corrosion resistant properties of titanium samples prepared by anodic oxidation with different surface morphologies. Pure titanium substrates were treated by anodic oxidation to obtain porous titanium films in micron, submicron, and micron-submicron scales. The surface morphologies, coating cross-sectional morphologies, crystalline structures, and surface roughness of these samples were characterized. Electrochemical technique was used to measure the corrosion potential (Ecorr), current density of corrosion (Icorr), and polarization resistance (Rp) of these samples in a simulated body fluid. Pure titanium could be modified to exhibit different surface morphologies by the anodic oxidation technique. The Tafel curve results showed that the technique can improve the corrosion resistance of pure titanium. Furthermore, the corrosion resistance varied with different surface morphologies. The submicron porous surface sample demonstrated the best corrosion resistance, with maximal Ecorr and Rp and minimal Icorr. Anodic oxidation technology can improve the corrosion resistance of pure titanium in a simulated body fluid. The submicron porous surface sample exhibited the best corrosion resistance because of its small surface area and thick barrier layer.

  16. Anodal vs cathodal stimulation of motor cortex: a modeling study

    NARCIS (Netherlands)

    Manola, L.; Holsheimer, J.; Veltink, Petrus H.; Buitenweg, Jan R.

    Objective. To explore the effects of electrical stimulation performed by an anode, a cathode or a bipole positioned over the motor cortex for chronic pain management. Methods. A realistic 3D volume conductor model of the human precentral gyrus (motor cortex) was used to calculate the

  17. Plasmonic properties of gold-coated nanoporous anodic alumina ...

    Indian Academy of Sciences (India)

    We present here a simple technique to align the nanopores in a linear fashion along lines by using an aluminium surface with linear scratch marks made on it prior to the anodization process. The nanopores tend to preferentially form along the scratch marks resulting in a linear organization of the nanopores to form an ...

  18. Electrochemical Impedance Modeling of a Solid Oxide Fuel Cell Anode

    DEFF Research Database (Denmark)

    Mohammadi, R.; Søgaard, Martin; Ramos, Tania

    2014-01-01

    A simulation package for the impedance response of SOFC anodes is presented here. The model couples the gas transport in gas channels and within a porous electrode with the electrochemical kinetics. The gas phase mass transport is modeled using mass conservation equations. A transmission line mod...

  19. Development of redox stable, multifunctional substrates for anode supported SOFCS

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Foghmoes, Søren Preben Vagn; Ramos, Tania

    2017-01-01

    upon redox cycling, while other properties such as catalytic activity for methane reforming and/or water gas shift, thermal conductivity in addition to electronic conductivity for current pickup are highly wanted for SOFC applications. In order to combine the advantages of a redox stable anode...

  20. Ferrate(VI synthesis at boron-doped diamond anode

    Directory of Open Access Journals (Sweden)

    Čekerevac Milan

    2013-01-01

    Full Text Available The oxidation of iron compounds from alkaline 10 M KOH electrolytes on a boron doped diamond electrode is examined by cyclic voltammetry between the potentials of hydrogen evolution reaction and oxygen evolution reaction, due to ferrate(VI electrochemical synthesis. It is shown that the anodic current peak that appears in iron free electrolyte at a less positive potential than the potential of oxygen evolution probably coincides with oxidation of hydrogen in >CH2 groups and C-sp2 graphite impurities with formation of >C=O groups at C-sp3 diamond structure. Addition of Fe(III compounds to the electrolyte provoke formation of the anodic wave on cyclic voltammograms in the potential region which correlates with generation of ferrate(VI. It is concluded that the direct electrochemical synthesis of Fe(VI at the boron doped diamond anode is possible because of the less positive potential of ferrate(VIFeO2-4 formation in respect to the potential of oxygen evolution reaction. Presence of ferrate(VI in electrolyte, formed after anodic polarization of boron electrode in 10 M KOH electrolyte saturated with Fe(III at + 0.9 V against Hg|HgO electrode, has been proven by UV-VIS spectrometry.

  1. Manufacturing of anode supported SOFCs: Processing parameters and their influence

    DEFF Research Database (Denmark)

    Ramousse, Severine; Menon, Mohan; Brodersen, Karen

    2007-01-01

    The establishment of low cost, highly reliable and reproducible manufacturing processes has been focused for commercialization of SOFC technology. A major challenge in the production chain is the manufacture of anode-supported planar SOFC's single cells in which each layer in a layered structure...

  2. Recovery of Silver and Gold from Copper Anode Slimes

    Science.gov (United States)

    Chen, Ailiang; Peng, Zhiwei; Hwang, Jiann-Yang; Ma, Yutian; Liu, Xuheng; Chen, Xingyu

    2015-02-01

    Copper anode slimes, produced from copper electrolytic refining, are important industrial by-products containing several valuable metals, particularly silver and gold. This article provides a comprehensive overview of the development of the extraction processes for recovering silver and gold from conventional copper anode slimes. Existing processes, namely pyrometallurgical processes, hydrometallurgical processes, and hybrid processes involving the combination of pyrometallurgical and hydrometallurgical technologies, are discussed based in part on a review of the form and characteristics of silver and gold in copper anode slimes. The recovery of silver and gold in pyrometallurgical processes is influenced in part by the slag and matte/metal chemistry and related characteristics, whereas the extraction of these metals in hydrometallurgical processes depends on the leaching reagents used to break the structure of the silver- and gold-bearing phases, such as selenides. By taking advantage of both pyrometallurgical and hydrometallurgical techniques, high extraction yields of silver and gold can be obtained using such combined approaches that appear promising for efficient extraction of silver and gold from copper anode slimes.

  3. Anode plasma dynamics in the self-magnetic-pinch diode

    Directory of Open Access Journals (Sweden)

    Nichelle Bruner

    2011-02-01

    Full Text Available The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsed-power-driven x-ray radiography. In high-power operation, the beam electrons desorb contaminants from the anode surface from which positive ions are drawn to the cathode. The counterstreaming electrons and ions establish an equilibrium current. It has long been recognized, however, that expanding electrode plasmas can disrupt this equilibrium and cause rapid reduction of the diode impedance and the radiation pulse. Recently developed numerical techniques, which enable simultaneous modeling of particle currents with 10^{13}  cm^{-3} densities to plasmas of near solid density, are applied to a model of the self-magnetic-pinch diode which includes the formation and evolution of anode surface plasmas. Two mechanisms are shown to cause rapid impedance loss, anode plasma expansion into the anode-cathode (A-K gap, and increased ion space-charge near the cathode surface. The former mechanism dominates for shorter A-K gaps, while the latter dominates for longer gaps. Model results qualitatively reproduce the time-dependent impedances measured for this diode.

  4. Fabrication of Porous Anodic Alumina with Ultrasmall Nanopores

    Directory of Open Access Journals (Sweden)

    Ding GuQiao

    2010-01-01

    Full Text Available Abstract Anodization of Al foil under low voltages of 1–10 V was conducted to obtain porous anodic aluminas (PAAs with ultrasmall nanopores. Regular nanopore arrays with pore diameter 6–10 nm were realized in four different electrolytes under 0–30°C according to the AFM, FESEM, TEM images and current evolution curves. It is found that the pore diameter and interpore distance, as well as the barrier layer thickness, are not sensitive to the applied potentials and electrolytes, which is totally different from the rules of general PAA fabrication. The brand-new formation mechanism has been revealed by the AFM study on the samples anodized for very short durations of 2–60 s. It is discovered for the first time that the regular nanoparticles come into being under 1–10 V at the beginning of the anodization and then serve as a template layer dominating the formation of ultrasmall nanopores. Under higher potentials from 10 to 40 V, the surface nanoparticles will be less and less and nanopores transform into general PAAs.

  5. Optical properties of alumina membranes prepared by anodic oxidation process

    International Nuclear Information System (INIS)

    Li Zhaojian; Huang Kelong

    2007-01-01

    The luminescence property of anodic alumina membranes (AAMs) with ordered nanopore arrays prepared by electrochemically anodizing aluminum in oxalic acid solutions have been investigated. Photoluminescence emission (PL) measurement shows that a blue PL band occurs in the wavelength ranges of 300-600 nm. The PL intensity and peak position of AAMs depend markedly on the excitation wavelength. A new peak located at 518 nm can be observed under a monitoring wavelength at 429 nm in the photoluminescence excitation (PLE) spectra. Convincing evidences have been presented that the PLE would be associated with the residual aluminum ions in the membrane. The PLE and PL of AAMs, as a function of anodizing times, have been discussed. It is found that the oxalic impurities incorporated in the AAMs would have important influences on the optical properties of AAMs in the initial stage of anodization. The PL and PLE spectra obtained show that there are three optical centers, of which the first is originated from the F + centers in AAMs, the second is correlated with the oxalic impurities incorporated in the AAMs, and the third is associated with the excess aluminum ions in the membrane

  6. Anodic oxide growth on Zr in neutral aqueous solution

    Indian Academy of Sciences (India)

    anodization and cathodic reactions on metal surfaces. Our sample, specially pre- pared for neutron reflectometry, was a sputter-deposited film on a polished Si(1 1 1) substrate, sufficiently thick to imitate a bulk metal. Upon removal from the sput- tering chamber and exposure to air, a passive oxide layer grew on the film. An.

  7. Optimal Set Anode Potentials Vary in Bioelectrochemical Systems

    KAUST Repository

    Wagner, Rachel C.

    2010-08-15

    In bioelectrochemical systems (BESs), the anode potential can be set to a fixed voltage using a potentiostat, but there is no accepted method for defining an optimal potential. Microbes can theoretically gain more energy by reducing a terminal electron acceptor with a more positive potential, for example oxygen compared to nitrate. Therefore, more positive anode potentials should allow microbes to gain more energy per electron transferred than a lower potential, but this can only occur if the microbe has metabolic pathways capable of capturing the available energy. Our review of the literature shows that there is a general trend of improved performance using more positive potentials, but there are several notable cases where biofilm growth and current generation improved or only occurred at more negative potentials. This suggests that even with diverse microbial communities, it is primarily the potential of the terminal respiratory proteins used by certain exoelectrogenic bacteria, and to a lesser extent the anode potential, that determines the optimal growth conditions in the reactor. Our analysis suggests that additional bioelectrochemical investigations of both pure and mixed cultures, over a wide range of potentials, are needed to better understand how to set and evaluate optimal anode potentials for improving BES performance. © 2010 American Chemical Society.

  8. Novel Ceramic Materials for Polymer Electrolyte Membrane Water Electrolysers' Anodes

    DEFF Research Database (Denmark)

    Polonsky, J.; Bouzek, K.; Prag, Carsten Brorson

    2012-01-01

    Tantalum carbide was evaluated as a possible new support for the IrO2 for use in anodes of polymer electrolyte membrane water electrolysers. A series of supported electrocatalysts varying in mass content of iridium oxide was prepared. XRD, powder conductivity measurements and cyclic and linear...

  9. Improving electrochemical performance of tin-based anodes formed ...

    Indian Academy of Sciences (India)

    ... and the electrical properties of the nanostructured Sn thin film electrode. The high cycleability and capacity retention were achieved when the nanostructured Cu–Sn–C thin film was used as an anode material since C increased the mechanical tolerance of the thin film to the volume expansion due to its grain refiner effect.

  10. Development of Planar Metal Supported SOFC with Novel Cermet Anode

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Hjelm, Johan; Klemensø, Trine

    2009-01-01

    , into which electrocatalytically active materials are infiltrated after sintering. The paper presents the recent results on the electrochemical performance and durability of the novel planar metal-supported SOFC design. The results presented in the paper show that the novel cell and anode design has...... a promising performance and durability at a broad range of temperatures and is especially suitable for intermediate temperature operation....

  11. Effect of anodization on corrosion behaviour and biocompatibility of ...

    Indian Academy of Sciences (India)

    The objective of this investigation is to study the effectiveness of anodized surface of commercial purity titanium (Cp-Ti) on ... aids. It has attractive bulk mechanical properties like low modulus of elasticity, high strength to weight ratio, excellent corrosion resistance, low rate of ion release combined with excellent biostability ...

  12. A review of liquid metal anode solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    ALIYA TOLEUOVA

    2013-06-01

    Full Text Available This review discusses recent advances in a solid oxide fuel cell (SOFC variant that uses liquid metal electrodes (anodes with the advantage of greater fuel tolerance and the ability to operate on solid fuel. Key features of the approach are discussed along with the technological and research challenges that need to be overcome for scale-up and commercialisation.

  13. Prelithiated Silicon Nanowires as an Anode for Lithium Ion Batteries

    KAUST Repository

    Liu, Nian

    2011-08-23

    Silicon is one of the most promising anode materials for the next-generation high-energy lithium ion battery (LIB), while sulfur and some other lithium-free materials have recently shown high promise as cathode materials. To make a full battery out of them, either the cathode or the anode needs to be prelithiated. Here, we present a method for prelithiating a silicon nanowire (SiNW) anode by a facile self-discharge mechanism. Through a time dependence study, we found that 20 min of prelithiation loads ∼50% of the full capacity into the SiNWs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies show that the nanostructure of SiNWs is maintained after prelithiation. We constructed a full battery using our prelithiated SiNW anode with a sulfur cathode. Our work provides a protocol for pairing lithium-free electrodes to make the next-generation high-energy LIB. © 2011 American Chemical Society.

  14. Unique Reduced Graphene Oxide as Efficient Anode Material in Li ...

    Indian Academy of Sciences (India)

    19

    Unique Reduced Graphene Oxide as Efficient Anode Material in Li Ion Battery. Sampath Kumar Puttapati1 ... Keywords: carbon materials; graphene oxide; energy storage; Li ion battery. *. Corresponding author. Tel: +91 40 2313 4453; .... Chowdari B V R 2014 J. Solid State Electrochem. 18 941. [4] Pei S -F and Cheng H -M ...

  15. Optimization and Domestic Sourcing of Lithium Ion Battery Anode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Wood, III, D. L.; Yoon, S. [A123 Systems, Inc.

    2012-10-25

    The purpose of this Cooperative Research and Development Agreement (CRADA) between ORNL and A123Systems, Inc. was to develop a low-temperature heat treatment process for natural graphite based anode materials for high-capacity and long-cycle-life lithium ion batteries. Three major problems currently plague state-of-the-art lithium ion battery anode materials. The first is the cost of the artificial graphite, which is heat-treated well in excess of 2000°C. Because of this high-temperature heat treatment, the anode active material significantly contributes to the cost of a lithium ion battery. The second problem is the limited specific capacity of state-of-the-art anodes based on artificial graphites, which is only about 200-350 mAh/g. This value needs to be increased to achieve high energy density when used with the low cell-voltage nanoparticle LiFePO4 cathode. Thirdly, the rate capability under cycling conditions of natural graphite based materials must be improved to match that of the nanoparticle LiFePO4. Natural graphite materials contain inherent crystallinity and lithium intercalation activity. They hold particular appeal, as they offer huge potential for industrial energy savings with the energy costs essentially subsidized by geological processes. Natural graphites have been heat-treated to a substantially lower temperature (as low as 1000-1500°C) and used as anode active materials to address the problems described above. Finally, corresponding graphitization and post-treatment processes were developed that are amenable to scaling to automotive quantities.

  16. Silicon Based Anodes for Li-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiguang; Wang, Wei; Xiao, Jie; Xu, Wu; Graff, Gordon L.; Yang, Zhenguo; Choi, Daiwon; Li, Xiaolin; Wang, Deyu; Liu, Jun

    2012-06-15

    Silicon is environmentally benign and ubiquitous. Because of its high specific capacity, it is considered one of the most promising candidates to replace the conventional graphite negative electrode used in today's Li ion batteries. Silicon has a theoretical specific capacity of nearly 4200 mAh/g (Li21Si5), which is 10 times larger than the specific capacity of graphite (LiC6, 372 mAh/g). However, the high capacity of silicon is associated with huge volume changes (more than 300 percent) when alloyed with lithium, which can cause severe cracking and pulverization of the electrode and lead to significant capacity loss. Significant scientific research has been conducted to circumvent the deterioration of silicon based anode materials during cycling. Various strategies, such as reduction of particle size, generation of active/inactive composites, fabrication of silicon based thin films, use of alternative binders, and the synthesis of 1-D silicon nanostructures have been implemented by a number of research groups. Fundamental mechanistic research has also been performed to better understand the electrochemical lithiation and delithiation process during cycling in terms of crystal structure, phase transitions, morphological changes, and reaction kinetics. Although efforts to date have not attained a commercially viable Si anode, further development is expected to produce anodes with three to five times the capacity of graphite. In this chapter, an overview of research on silicon based anodes used for lithium-ion battery applications will be presented. The overview covers electrochemical alloying of the silicon with lithium, mechanisms responsible for capacity fade, and methodologies adapted to overcome capacity degradation observed during cycling. The recent development of silicon nanowires and nanoparticles with significantly improved electrochemical performance will also be discussed relative to the mechanistic understanding. Finally, future directions on the

  17. Diffusion Limitations in the Porous Anodes of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Williford, Rick E.; Chick, Lawrence A.; Maupin, Gary D.; Simner, Steve P.; Stevenson, Jeffry W.

    2003-08-01

    Concentration polarization is important because it determines the maximum power output of a solid oxide fuel cell (SOFC) at high fuel utilization. Anodic concentration polarization occurs when the demand for reactants exceeds the capacity of the porous ceramic anode to supply them by gas diffusion mechanisms. Many models simulate this behavior by assuming an anomolous high value for the tortuosity (eg, t=17), a measure of the bulk diffusional resistance for a porous ceramic. However, recent experiments at several laboratories, including results reported herein, have provided strong evidence that typical sintered powder ceramics (30-50% porosity) have much lower tortuosities (t=2.5-3), indicating that the bulk diffusional resistance is too small to be responsible for concentration polarization. We find evidence that concentration polarization originates in the immediate vicinity of the reactive sites near the anode/electrolyte interface, at the triple phase boundaries (TPBs) between the Ni catalyst particles, the gas, and the oxygen conducting YSZ ceramic. A model is proposed to describe how concentration polarization is controlled by two localized phenomena: competitive adsorption of reactants in areas adjacent to the reactive TPB sites, followed by relatively slow surface diffusion to the reactive sites. The model parameters (adsorption activation energy and surface diffusion coefficients) were determined by fitting to well-characterized SOFC voltage-current performance data, and are in good agreement with data from the literature. Results suggest that future SOFC design improvements should focus on optimization of the reactive area, adsorption, and surface diffusion at the anode/electrolyte interface, rather than on anode thicknesses or bulk porosities.

  18. Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment.

    Science.gov (United States)

    Garcia-Segura, Sergi; Keller, Jürg; Brillas, Enric; Radjenovic, Jelena

    2015-01-01

    Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl(-) ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl2/HClO/ClO(-)), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO(-) species led to the production of ClO3(-) and ClO4(-) ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Corrosion of cermet anodes during low temperature electrolysis of alumina. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kozarek, R.L.; Ray, S.P.; Dawless, R.K.; LaCamera, A.F.

    1997-09-26

    Successful development of inert anodes to replace carbon anodes in Hall cells has the potential benefits of lower energy consumption,lower operating costs, and reduced CO{sub 2} and CO emissions. Using inert anodes at reduced current density and reduced operating temperature (800 C) has potential for decreasing the corrosion rate of inert anodes. It may also permit the use of new materials for containment and insulation. This report describes the fabrication characteristics and the corrosion performance of 5324-17% Cu Cermet anodes in 100 hour tests. Although some good results were achieved, the corrosion rate at low temperature (800 C) is varied and not significantly lower than typical results at high temperature ({approximately} 960 C). This report also describes several attempts at 200 hour tests, with one anode achieving 177 hours of continuous operation and another achieving a total of 235 hours but requiring three separate tests of the same anode. The longest run did show a lower wear rate in the last test; but a high resistance layer developed on the anode surface and forced an unacceptably low current density. It is recommended that intermediate temperatures be explored as a more optimal environment for inert anodes. Other electrolyte chemistries and anode compositions (especially high conductivity anodes) should be considered to alleviate problems associated with lower temperature operation.

  20. Modular anode assemblies and methods of using the same for electrochemical reduction

    Energy Technology Data Exchange (ETDEWEB)

    Wiedmeyer, Stanley G; Barnes, Laurel A; Williamson, Mark A; Willit, James L

    2015-02-17

    Modular anode assemblies are used in electrolytic oxide reduction systems for scalable reduced metal production via electrolysis. Assemblies include a channel frame connected to several anode rods extending into an electrolyte. An electrical system powers the rods while being insulated from the channel frame. A cooling system removes heat from anode rods and the electrical system. An anode guard attaches to the channel frame to prevent accidental electrocution or damage during handling or repositioning. Each anode rod may be divided into upper and lower sections to permit easy repair and swapping out of lower sections. The modular assemblies may have standardized components to permit placement at multiple points within a reducing system. Example methods may operate an electrolytic oxide reduction system by positioning the modular anode assemblies in the reduction system and applying electrical power to the plurality of anode assemblies.

  1. Modeling a short dc discharge with thermionic cathode and auxiliary anode

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, E. [St. Petersburg State University, St. Petersburg 199034 (Russian Federation); University ITMO, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); Demidov, V. I. [St. Petersburg State University, St. Petersburg 199034 (Russian Federation); West Virginia University, Morgantown, West Virginia 26506 (United States); Kaganovich, I. D. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Koepke, M. E. [West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A. [St. Petersburg State University, St. Petersburg 199034 (Russian Federation)

    2013-10-15

    A short dc discharge with a thermionic cathode can be used as a current and voltage stabilizer, but is subject to current oscillation. If instead of one anode two anodes are used, the current oscillations can be reduced. We have developed a kinetic model of such a discharge with two anodes, where the primary anode has a small opening for passing a fraction of the discharge current to an auxiliary anode. The model demonstrates that the current-voltage relationship of the discharge with two anodes is characterized everywhere by positive slope, i.e., positive differential resistance. Therefore, the discharge with two anodes is expected to be stable to the spontaneous oscillation in current that is induced by negative differential resistance. As a result, such a discharge can be used in an engineering application that requires stable plasma, such as a current and voltage stabilizer.

  2. Modeling of the anode surface deformation in high-current vacuum arcs with AMF contacts

    International Nuclear Information System (INIS)

    Huang, Xiaolong; Wang, Lijun; Deng, Jie; Jia, Shenli; Qin, Kang; Shi, Zongqian

    2016-01-01

    A high-current vacuum arc subjected to an axial magnetic field is maintained in a diffuse status. With an increase in arc current, the energy carried by the arc column to the anode becomes larger and finally leads to the anode temperature exceeding the melting point of the anode material. When the anode melting pool is formed, and the rotational plasma of the arc column delivers its momentum to the melting pool, the anode melting pool starts to rotate and also flow outwards along the radial direction, which has been photographed by some researchers using high-speed cameras. In this paper, the anode temperature and melting status is calculated using the melting and solidification model. The swirl flow of the anode melting pool and deformation of the anode is calculated using the magneto-hydrodynamic (MHD) model with the volume of fraction (VOF) method. All the models are transient 2D axial-rotational symmetric models. The influence of the impaction force of the arc plasma, electromagnetic force, viscosity force, and surface tension of the liquid metal are all considered in the model. The heat flux density injected into the anode and the arc pressure are obtained from the 3D numerical simulation of the high-current vacuum arc using the MHD model, which gives more realistic parameters for the anode simulation. Simulation results show that the depth of the anode melting pool increases with an increase in the arc current. Some droplets sputter out from the anode surface, which is caused by the inertial centrifugal force of the rotational melting pool and strong plasma pressure. Compared with the previous anode melting model without consideration of anode deformation, when the deformation and swirl flow of the anode melting pool are considered, the anode temperature is relatively lower, and just a little more than the melting point of Cu. This is because of liquid droplets sputtering out of the anode surface taking much of the energy away from the anode surface. The

  3. Modeling of anodic dissolution of U Pu Zr ternary alloy in the molten LiCl KCl electrolyte

    Science.gov (United States)

    Iizuka, Masatoshi; Kinoshita, Kensuke; Koyama, Tadafumi

    2005-02-01

    The metallic fuel anode in the molten salt electrorefining step for the pyrometallurgical reprocessing was modeled based on the findings from the anodic dissolution tests using a U Pu Zr ternary alloy. This anode model simulates selective dissolution of uranium and plutonium at lower anode potential, growth of a diffusion controlling layer consisting of a mixture of the molten salt electrolyte and the remaining zirconium metal, and simultaneous dissolution of all the constituents at higher anode potential. The calculation with this model reproduced well the actual anodic behavior of the U Pu Zr ternary alloy such as two-step rapid rise in the anode potential.

  4. Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Woodworth James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  5. X-ray tube with needle-like anode

    International Nuclear Information System (INIS)

    Slapa, M.; Stras, W.; Traczyk, M.; Snopek, M.; Drabik, W.; Dora, J.; Gutowski, R.

    2002-01-01

    An X-ray tube a needle-like anode (NAXT) built in our Laboratory, its design and basic operating parameters are presented. The process of electron beam forming and influence of external and internal magnetic fields is discussed. The tube properties essential from the point of view of its application in X-ray generators as well as disadvantageous thermal effects caused by flow of heat generated in the tube target to irradiated objects are discussed. The tube is almost a point-like source of X radiation emitted into 4π geometry; the dose rates are on the order of 1 Gy/min at a distance of 10 mm from the anode cup. Preliminary tests show the tube may be useful in brachytherapy of cancer tumors of diameter up to 30 mm. The tube may also be an interesting device in widely understood field of irradiation techniques. (author)

  6. Very High Isp Thruster with Anode Layer (VHITAL): An Overview

    Science.gov (United States)

    Marrese-Reading, Colleen M.; Frisbee, Robert; Sengupta, Anita; Cappelli, Mark A.; Tverdoklebov, Sergey; Semenkin, Sasha; Boyd, Iain

    2004-01-01

    This article describes the two stage bismuth fueled Hall thruster technology that was developed at TsNIIMASH [1] and the Very High Isp Thruster with Anode Layer (VHITAL) technology assessment program that is funded by NASA Exploration Systems Mission Directorate (ESMD)' Prometheus program. The overall objective of this program is to evaluate the potential for this Russian-developed thruster technology to enable near-term, Nuclear Electric Propulsion (NEf)-enabled ESMD missions to the outer planets. This 2.5 year program will provide the technology basis for the development of even higher power anode layer thrusters for rapid outer planet exploration missions and, ultimately, human exploration of the solar system. The first 6 month phase is currently in progress. If this phase is successful, the second (1 year) and third (1 year) phase of the proposed program will follow.

  7. Accelerated creep of Ni-YSZ anodes during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Greco, Fabio; Ni, De Wei

    2014-01-01

    load-carrying component. In this work we report on a new creep-reduction phenomenon observed to take place during the reduction process itself, where stresses are relaxed at a rate much faster (~×104) than during operation where the anode is in fully reduced state. Furthermore, samples exposed...... to a very small tensile stress (0.004 MPa) were observed to expand during reduction, which is in contrast with reports in literature [Ref].The “accelerated” creep has a tremendous impact on the stress field in an operating SOFC stack. Creep experiments, where carried out on NiO-YSZ anode support structures...... loaded in three point bending or uniaxial tension and the deformations recorded during the reduction process. The fast creep is observed only during the reduction, but due to the extremely high rate this will effectively relax all the residual compressive stresses in the electrolyte at the reduction...

  8. SOFC anode reduction studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    for studying these nanoscale structures, but only few SOFC studies have applied in situ TEM to observe the ceramic nanostructures in a reactive gas environment at elevated temperatures. The present contribution focuses on the reduction of an SOFC anode which is a necessary process to form the catalytically......The Solid Oxide Fuel Cell (SOFC) is a promising part of future energy approaches due to a relatively high energy conversion efficiency and low environmental pollution. SOFCs are typically composed of ceramic materials which are highly complex at the nanoscale. TEM is routinely applied ex situ...... active Ni surface before operating the fuel cells. The reduction process was followed in the TEM while exposing a NiO/YSZ (YSZ = Y2O3-stabilized ZrO2) model anode to H2 at T = 250-1000⁰C. Pure NiO was used in reference experiments. Previous studies have shown that the reduction of pure Ni...

  9. Current Trends in Nanoporous Anodized Alumina Platforms for Biosensing Applications

    Directory of Open Access Journals (Sweden)

    Ganesan Sriram

    2016-01-01

    Full Text Available Pristine aluminum (Al has received great deal of attention on fabrication of nanoporous anodized alumina (NAA with arrays of nanosized uniform pores with controllable pore sizes and lengths by the anodization process. There are many applications of NAA in the field of biosensors due to its numerous key factors such as ease of fabrication, high surface area, chemical stability and detection of biomolecules through bioconjugation of active molecules, its rapidness, and real-time monitoring. Herein, we reviewed the recent trends on the fabrication of NAA for high sensitive biosensor platforms like bare sensors, gold coated sensors, multilayer sensors, and microfluidic device supported sensors for the detection of various biomolecules. In addition, we have discussed the future prospectus about the improvement of NAA based biosensors for the detection of biomolecules.

  10. Niobium-doped strontium titanates as SOFC anodes

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L. Reine

    2008-01-01

    been synthesized with a recently developed modified glycine-nitrate process. The synthesized powders have been calcined and sintered in air or in 9% H(2) / N(2) between 800 - 1400 degrees C. After calcination the samples were single phase Nb-doped strontium titanate with grain sizes of less than 100 nm...... in diameter on average. The phase purity, defect structure, and microstructure of the materials have been analyzed with SEM, XRD, and TGA. The electrical conductivity of the Nb-doped titanate decreased with increasing temperature and showed a phonon scattering conduction mechanism with sigma > 120 S...... ability of the Nb-doped titanates to be used as a part of a SOFC anode. However, the catalytic activity of the materials was not sufficient and it needs to be improved if titanate based materials are to be realized as constituents in SOFC anodes....

  11. Electrocatalyst for alcohol oxidation at fuel cell anodes

    Science.gov (United States)

    Adzic, Radoslav [East Setauket, NY; Kowal, Andrzej [Cracow, PL

    2011-11-02

    In some embodiments a ternary electrocatalyst is provided. The electrocatalyst can be used in an anode for oxidizing alcohol in a fuel cell. In some embodiments, the ternary electrocatalyst may include a noble metal particle having a surface decorated with clusters of SnO.sub.2 and Rh. The noble metal particles may include platinum, palladium, ruthenium, iridium, gold, and combinations thereof. In some embodiments, the ternary electrocatalyst includes SnO.sub.2 particles having a surface decorated with clusters of a noble metal and Rh. Some ternary electrocatalysts include noble metal particles with clusters of SnO.sub.2 and Rh at their surfaces. In some embodiments the electrocatalyst particle cores are nanoparticles. Some embodiments of the invention provide a fuel cell including an anode incorporating the ternary electrocatalyst. In some aspects a method of using ternary electrocatalysts of Pt, Rh, and SnO.sub.2 to oxidize an alcohol in a fuel cell is described.

  12. Electrocatalytic Properties of BDD Anodes: Its Loosely Adsorbed Hydroxyl Radicals

    Directory of Open Access Journals (Sweden)

    Nicolaos Vatistas

    2012-01-01

    Full Text Available The high oxidative action of boron doped diamond (BDD anodes on the biorefractory organic compounds has been attributed to the low adsorption of the generated hydroxyl radicals on the BDD surface in respect to other anodic materials. In a previous paper, the effect of low adsorption of BBD has been studied by proposing a continuum approach to represent the adsorption layer. The oxidative action of the hydroxyl radicals is attributed to the values of their diffusivity into the adsorption and adjacent reactive layer as well as to the value of kinetic constant in both layers. In this paper, more details on both layers are reported in order to justify the proposed continuum approach as well as the assumptions concerning diffusivity and kinetic constant in both adsorption and reactive layers, where the oxidative action of hydroxyl radicals occurs.

  13. CO tolerance effects of tungsten-based PEMFC anodes

    International Nuclear Information System (INIS)

    Pereira, Luis Gustavo S.; Santos, Fatima R. dos; Pereira, Maristela E.; Paganin, Valdecir A.; Ticianelli, Edson A.

    2006-01-01

    The performance of proton exchange membrane fuel cells (PEMFC) fed with CO-contaminated hydrogen was investigated for anodes with PtWO x /C and phosphotungstic acid (PTA) impregnated Pt/C electrocatalysts. A quite high performance was achieved for the PEMFC fed with H 2 + 100 ppm CO with anodes containing 0.4 mg PtWO x cm -2 and also for those with 0.4 mg Pt cm -2 impregnated with ca. 1 mg PTA cm -2 . A decay of the single cell performance with time is observed, and this was attributed to an increase of the membrane resistance due to the polymer degradation promoted by the crossover of the tungsten species throughout the membrane

  14. Anodic etching of p-type cubic silicon carbide

    Science.gov (United States)

    Harris, G. L.; Fekade, K.; Wongchotigul, K.

    1992-01-01

    p-Type cubic silicon carbide was anodically etched using an electrolyte of HF:HCl:H2O. The etching depth was determined versus time with a fixed current density of 96.4 mA/sq cm. It was found that the etching was very smooth and very uniform. An etch rate of 22.7 nm/s was obtained in a 1:1:50 HF:HCl:H2O electrolyte.

  15. Improving electrochemical performance of tin-based anodes formed ...

    Indian Academy of Sciences (India)

    decomposes into Li–Sn alloys (2) surrounded by Cu matrix ... Mg, Ba, Sr, Ca, La, Ce, Si, Ge, C, P, B, Pb, Bi, Sb, Al, Ga, In,. Tl, Zn, Be ... et al 2011). However, since Co is very expensive and toxic, the need for finding alternative anode materials is still under discussion. In this study, bare Sn and composite Cu–Sn and Cu–Sn–.

  16. Novel Anode Catalyst for Direct Methanol Fuel Cells

    OpenAIRE

    Basri, S.; Kamarudin, S. K.; Daud, W. R. W.; Yaakob, Z.; Kadhum, A. A. H.

    2014-01-01

    PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffracti...

  17. Water and oil wettability of anodized 6016 aluminum alloy surface

    Science.gov (United States)

    Rodrigues, S. P.; Alves, C. F. Almeida; Cavaleiro, A.; Carvalho, S.

    2017-11-01

    This paper reports on the control of wettability behaviour of a 6000 series aluminum (Al) alloy surface (Al6016-T4), which is widely used in the automotive and aerospace industries. In order to induce the surface micro-nanostructuring of the surface, a combination of prior mechanical polishing steps followed by anodization process with different conditions was used. The surface polishing with sandpaper grit size 1000 promoted aligned grooves on the surface leading to static water contact angle (WCA) of 91° and oil (α-bromonaphthalene) contact angle (OCA) of 32°, indicating a slightly hydrophobic and oleophilic character. H2SO4 and H3PO4 acid electrolytes were used to grow aluminum oxide layers (Al2O3) by anodization, working at 15 V/18° C and 100 V/0 °C, respectively, in one or two-steps configuration. Overall, the anodization results showed that the structured Al surfaces were hydrophilic and oleophilic-like with both WCA and OCA below 90°. The one-step configuration led to a dimple-shaped Al alloy surface with small diameter of around 31 nm, in case of H2SO4, and with larger diameters of around 223 nm in case of H3PO4. The larger dimples achieved with H3PO4 electrolyte allowed to reach a slight hydrophobic surface. The thicker porous Al oxide layers, produced by anodization in two-step configuration, revealed that the liquids can penetrate easily inside the non-ordered porous structures and, thus, the surface wettability tended to superhydrophilic and superoleophilic character (CA mechanisms of porous structures, was broken. Moreover, thicker oxide layers with narrow pores of about 29 nm diameter allowed to achieve WCA mechanical components or in water-oil separation process.

  18. Photoconductivity of Germanium Nanowire Arrays Incorporated in Anodic Aluminum Oxide

    International Nuclear Information System (INIS)

    Polyakov, B; Prikulis, J; Grigorjeva, L; Millers, D; Daly, B; Holmes, J D; Erts, D

    2007-01-01

    Photoconductivity of germanium nanowire arrays of 50 and 100 nm diameter incorporated into Anodic Aluminum Oxide (AAO) membranes illuminated with visible light is investigated. Photocurrent response to excitation radiation with time constants faster than 10 -4 s were governed by absorption of incident light by nanowires, while photokinetics with time constants of the order of 10 -3 s originates from the photoluminescence of the AAO matrix. Possible applications of nanowire arrays inside AAO as photoresistors are discussed

  19. Characteristics of the low power cylindrical anode layer ion source

    International Nuclear Information System (INIS)

    Zhao Jie; Tang Deli; Cheng Changming; Geng Shaofei

    2009-01-01

    A low power cylindrical anode layer ion source and its working characteristic, and the beam distribution are introduced. This ion source has two working states, emanative state and collimated state, and the normal parameters of this system are: working voltage 200-1200 V, discharge current 0.1-1.4A, air pressure 1.9 x 10 -2 -1.7 x 10 -1 Pa, gas flow 5-20 sccm. (authors)

  20. MeV ion beam polishing of anodically grown alumina

    International Nuclear Information System (INIS)

    Daudin, B.; Martin, P.

    1988-01-01

    When bombarded with 1 MeV N + ions, the surface of anodically grown alumina films is smoothened. This polishing effect was studied as a function of the ion bombardment fluence and of the substrate temperature in the range 80 - 650 K. The techniques used to characterize the surface roughness were Rutherford Backscattering Spectrometry, Scanning Electron Microscopy and small angle X-rays diffusion. It is suggested that atomic and/or electronic sputtering is responsible for the smoothing effect which was observed

  1. Detailed characterization of anode-supported SOFCs by impedance spectroscopy

    DEFF Research Database (Denmark)

    Barfod, R.; Mogensen, Mogens Bjerg; Klemensø, Trine

    2007-01-01

    Anode-supported thin electrolyte cells are studied by electrochemical impedance spectroscopy (EIS). The aim is to describe how the losses of this type of cells are distributed at low current density (around open-circuit voltage) as a function of temperature. An equivalent circuit consisting of an...... that the difference in performance originates from microstructural differences on the cathode. This is further supported by the observation of large differences in the cathode microstructure by scanning electron microscope....

  2. Lithium-Boron Alloy Anodes for Molten Salt Batteries (II)

    Science.gov (United States)

    1978-05-15

    Eagle - Picher Industries, Inc. Electronics Division, Couples Dept. Attn: D. R. Cottingham J. Dines D. L. Smith J. Wilson P. 0. Box 47 Joplin, MO 64801... Eagle - Picher Industries, Inc. Miami Research Laboratories Attn: P. E. Grayson 200 Ninth Avenue, N.E. Miami, OK 74354 ESB Research Center Attn: Library...777.. -~ -- NSWC/WOL TR 78-63 LITHIUM-BORON ALLOY ANODES FOR MOLTEN SALT BATTERIES (11) BY S.DALLEK, D. W. ERNST, 0 B. F. LARRICK Ott RESEARCH AND

  3. Nanocarbon-Coated Porous Anodic Alumina for Bionic Devices

    Directory of Open Access Journals (Sweden)

    Morteza Aramesh

    2015-08-01

    Full Text Available A highly-stable and biocompatible nanoporous electrode is demonstrated herein. The electrode is based on a porous anodic alumina which is conformally coated with an ultra-thin layer of diamond-like carbon. The nanocarbon coating plays an essential role for the chemical stability and biocompatibility of the electrodes; thus, the coated electrodes are ideally suited for biomedical applications. The corrosion resistance of the proposed electrodes was tested under extreme chemical conditions, such as in boiling acidic/alkali environments. The nanostructured morphology and the surface chemistry of the electrodes were maintained after wet/dry chemical corrosion tests. The non-cytotoxicity of the electrodes was tested by standard toxicity tests using mouse fibroblasts and cortical neurons. Furthermore, the cell–electrode interaction of cortical neurons with nanocarbon coated nanoporous anodic alumina was studied in vitro. Cortical neurons were found to attach and spread to the nanocarbon coated electrodes without using additional biomolecules, whilst no cell attachment was observed on the surface of the bare anodic alumina. Neurite growth appeared to be sensitive to nanotopographical features of the electrodes. The proposed electrodes show a great promise for practical applications such as retinal prostheses and bionic implants in general.

  4. Development of hollow anode penning ion source for laboratory application

    Science.gov (United States)

    Das, B. K.; Shyam, A.; Das, R.; Rao, A. D. P.

    2012-03-01

    The research work presented here focuses for the development of miniature penning type ion source. One hollow anode penning type ion source was developed in our laboratory. The size of the ion source is 38 mm diameter and 55 mm length. The ion source consists of two cathodes, a hollow anode and one piece of rare earth permanent magnet. The plasma was created in the plasma region between cathodes and the hollow anode. The J × B force in the region helps for efficient ionization of the gas even in the high vacuum region˜1×10 -5 Torr. The ions were extracted in the axial direction with help of the potential difference between the electrodes and the geometry of the extraction angle. The effect of the extraction electrode geometry for efficient extraction of the ions from the plasma region was examined. This ion source is a self extracted ion source. The self extracted phenomena reduce the cost and the size of the ion source. The extracted ion current was measured by a graphite probe. An ion current of more than 200 μA was observed at the probe placed 70 mm apart from the extraction electrode. In this paper, the structure of the ion source, effect of operating pressure, potential difference and the magnetic field on the extracted ion current is reported.

  5. Effect of sealing on the morphology of anodized aluminum oxide

    International Nuclear Information System (INIS)

    Hu, Naiping; Dong, Xuecheng; He, Xueying; Browning, James F.; Schaefer, Dale W.

    2015-01-01

    Highlights: • We explored structural change of anodizing aluminum oxide induced by sealing. • All sealing methods decrease pore size as shown by X-ray/neutron scattering. • Cold sealing and hot water sealing do not alter the aluminum oxide framework. • Hot nickel acetate sealing both fills the pores and deposits on air oxide interface. • Samples with hot nickel acetate sealing outperform other sealing methods. - Abstract: Ultra-small angle X-ray scattering (USAXS), small-angle neutron scattering (SANS), X-ray reflectometry (XRR) and neutron reflectometry (NR) were used to probe structure evolution induced by sealing of anodized aluminum. While cold nickel acetate sealing and hot-water sealing decrease pore size, these methods do not alter the cylindrical porous framework of the anodic aluminum oxide layer. Hot nickel acetate both fills the pores and deposits on the air surface (air–oxide interface), leading to low porosity and small mean pore radius (39 Å). Electrochemical impedance spectroscopy and direct current polarization show that samples sealed by hot nickel acetate outperform samples sealed by other sealing methods

  6. Transparent anodes for polymer photovoltaics: Oxygen permeability of PEDOT

    DEFF Research Database (Denmark)

    Andersen, M.; Carlé, Jon Eggert; Cruys-Bagger, N.

    2007-01-01

    The oxygen permeability of the transparent organic anode poly(3,4,-ethylene dioxythiophene) with paratoluenesulphonate as the anion (PEDOT:pTS) was determined to be 2.5 +/- 0.7 x 10(-15) cm(3) (STP) CM cm(-2) S-1 Pa-1, and is thus comparable in magnitude to the oxygen permeability of polyethylene......The oxygen permeability of the transparent organic anode poly(3,4,-ethylene dioxythiophene) with paratoluenesulphonate as the anion (PEDOT:pTS) was determined to be 2.5 +/- 0.7 x 10(-15) cm(3) (STP) CM cm(-2) S-1 Pa-1, and is thus comparable in magnitude to the oxygen permeability...... of polyethyleneterephthalate (PET). The oxygen diffusion through bilayers of polyethylene (PE) and PEDOT:pTS and bilayers of PET and PEDOT:pTS was established. The bilayer structures were applied as the carrier substrate and the transparent anode in polymer-based photovoltaic devices employing a mixture of poly(1-methoxy-4...... of the devices with PET as the carrier substrate degraded more slowly due to the lower oxygen and water permeability, whereas devices using PE as the carrier substrate gave devices with a very short lifetime. It was found that PEDOT:pTS on its own is a not a significant barrier for oxygen in the context...

  7. Biodegradation and cytotoxic properties of pulse anodized Mg alloys

    Science.gov (United States)

    Kim, Yu Kyoung; Park, Il Song; Lee, Sook Jeong; Lee, Min Ho

    2013-03-01

    Magnesium has the potential to be used as an implant material owing to its non-toxicity. On the other hand, magnesium alloys corrode rapidly in subcutaneous gas bubbles. Consequently, the approach of using magnesium alloys as a biodegradable biomaterial is not well established. Therefore, the aim of this study was to provide corrosion protection by anodizing to surface for a biodegradable material. Micro-arc oxidation by pulsed DC was applied to AZ91D and AZ31B, and the cell bioactivity was defined. The anodic film was characterized by XRD and SEM. The specific mass loss variation from immersion test and potentiodynamic electrochemical test was performed for the quantification of corrosion resistance. Although the AZ91D had better corrosion resistance properties but the result of the in vitro tests showed low cell viability compared with the AZ31B. The results of the cell staining and agar overlay test revealed the AZ31B group had good biocompatibility and a low corrosion rate. In this study, the surfaces of AZ91D and AZ31B showed the formation of a uniform film by pulse power anodization improving corrosion resistance. Also, the cytotoxicity of the materials was examined by the aluminum content change of compound metal.

  8. Position-sensitive proportional counter with low-resistance metal-wire anode

    International Nuclear Information System (INIS)

    Kopp, M.K.

    1980-01-01

    A position-sensitive proportional counter circuit is provided which uses a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counther. A pair of specially designed activecapacitance preamplifiers terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, lownoise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at te anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates

  9. Effects of anode flooding on the performance degradation of polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kim, Mansu; Jung, Namgee; Eom, KwangSup; Yoo, Sung Jong; Kim, Jin Young; Jang, Jong Hyun; Kim, Hyoung-Juhn; Hong, Bo Ki; Cho, EunAe

    2014-11-01

    Polymer electrolyte membrane fuel cell (PEMFC) stacks in a fuel cell vehicle can be inevitably exposed to harsh environments such as cold weather in winter, causing water flooding by the direct flow of condensed water to the electrodes. In this study, anode flooding was experimentally investigated with condensed water generated by cooling the anode gas line during a long-term operation (∼1600 h). The results showed that the performance of the PEMFC was considerably degraded. After the long-term experiment, the thickness of the anode decreased, and the ratio of Pt to carbon in the anode increased. Moreover, repeated fuel starvation of the half-cell severely oxidized the carbon surface due to the high induced potential (>1.5 VRHE). The cyclic voltammogram of the anode in the half-cell experiments indicated that the characteristic feature of the oxidized carbon surface was similar to that of the anode in the single cell under anode flooding conditions during the long-term experiment. Therefore, repeated fuel starvation by anode flooding caused severe carbon corrosion in the anode because the electrode potential locally increased to >1.0 VRHE. Consequently, the density of the tri-phase boundary decreased due to the corrosion of carbons supporting the Pt nanoparticles in the anode.

  10. Effect of zinc addition on the performance of aluminium alloy sacrificial anode for marine application

    Science.gov (United States)

    Khan, Bharvez; Rosli, M. U.; Jahidi, H.; Ishak, Muhammad Ikman; Zakaria, M. S.; Jamalludin, Mohd Riduan; Khor, C. Y.; Faizal, W. M.; Rahim, W. M.; Nawi, M. A. M.

    2017-09-01

    In this work, the effect of zinc addition on the performance of aluminum-based sacrificial anode in seawater was investigated. The parameters used in assessing the performance of the cast anodes are anodic efficiency, protection efficiency and polarized potential. The content of zinc in the anodes was varied after die casting. The alloys produced were tested as sacrificial anode for the protection of mild steel for marine application at room temperature. Factors such as reactivity of zinc particles in the seawater, corrosion activity during the period of experiment, pH of seawater and the electronegativity potential of zinc were collected for analysis. Overall findings shows addition of zinc increases rate of corrosion to the sacrificial anode and the protection offered by the sacrificial anodes measured and collected in PIT shows the seawater react to sacrificial anode and no porosity reaction between the anodes. The microstructure showed the intermetallic structures of β-phase which breakdown the alumina passive film, thus enhancing the anode efficiency.

  11. Density control of electrodeposited Ni nanoparticles/nanowires inside porous anodic alumina templates by an exponential anodization voltage decrease.

    Science.gov (United States)

    Marquardt, B; Eude, L; Gowtham, M; Cho, G; Jeong, H J; Châtelet, M; Cojocaru, C S; Kim, B S; Pribat, D

    2008-10-08

    Porous alumina templates have been fabricated by applying an exponential voltage decrease at the end of the anodization process. The time constant η of the exponential voltage function has been used to control the average thickness and the thickness distribution of the barrier layer at the bottom of the pores of the alumina structure. Depending on the η value, the thickness distribution of the barrier layer can be made very uniform or highly scattered, which allows us to subsequently fine tune the electrodeposition yield of nickel nanoparticles/nanowires at low voltage. As an illustration, the pore filling percentage with Ni has been varied, in a totally reproducible manner, between ∼3 and 100%. Combined with the ability to vary the pore diameter and repetition step over ∼2 orders of magnitude (by varying the anodization voltage and electrolyte type), the control of the pore filling percentage with metal particles/nanowires could bring novel approaches for the organization of nano-objects.

  12. A novel compensation method for the anode gain non-uniformity of multi-anode photomultiplier tubes.

    Science.gov (United States)

    Lee, Chan Mi; Il Kwon, Sun; Ko, Guen Bae; Ito, Mikiko; Yoon, Hyun Suk; Lee, Dong Soo; Hong, Seong Jong; Lee, Jae Sung

    2012-01-07

    The position-sensitive multi-anode photomultiplier tube (MA-PMT) is widely used in high-resolution scintillation detectors. However, the anode gain nonuniformity of this device is a limiting factor that degrades the intrinsic performance of the detector module. The aim of this work was to develop a gain compensation method for the MA-PMT and evaluate the resulting enhancement in the performance of the detector. The method employs a circuit that is composed only of resistors and is placed between the MA-PMT and a resistive charge division network (RCN) used for position encoding. The goal of the circuit is to divide the output current from each anode, so the same current flows into the RCN regardless of the anode gain. The current division is controlled by the combination of a fixed-value series resistor with an output impedance that is much larger than the input impedance of the RCN, and a parallel resistor, which detours part of the current to ground. PSpice simulations of the compensation circuit and the RCN were performed to determine optimal values for the compensation resistors when used with Hamamatsu H8500 MAPMTs. The intrinsic characteristics of a detector module consisting of this MA-PMT and a lutetium-gadolinium-oxyorthosilicate (LGSO) crystal array were tested with and without the gain compensation method. In simulation, the average coefficient of variation and max/min ratio decreased from 15.7% to 2.7% and 2.0 to 1.2, respectively. In the flood map of the LGSO-H8500 detector, the uniformity of the photopeak position for individual crystals and the energy resolution were much improved. The feasibility of the method was shown by applying it to an octagonal prototype positron emission tomography scanner.

  13. Cu--Ni--Fe anode for use in aluminum producing electrolytic cell

    Energy Technology Data Exchange (ETDEWEB)

    Bergsma, S. Craig; Brown, Craig W.; Bradford, Donald R; Barnett, Robert J.; Mezner, Michael B.

    2006-07-18

    A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900.degree. C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu--Ni--Fe anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

  14. Characteristics from Recycled of Zinc Anode used as a Corrosion Preventing Material on Board Ship

    Science.gov (United States)

    Barokah, B.; Semin, S.; Kaligis, D. D.; Huwae, J.; Fanani, M. Z.; Rompas, P. T. D.

    2018-02-01

    The objective of this research is to obtain the values of chemical composition, electrochemical potential and electrochemical efficiency. Methods used were experiment with physical tests conducted in metallurgical laboratory and DNV-RP-B401 cathode protection design DNV (Det Norske Veritas) standard. The results showed that the composition of chemical as Zinc (Zn), Aluminium, Cadmium, Plumbumb, Copper and Indium is suitable of standard. The values of electrochemical potential and electrochemical efficiency were respectively. However it can be concluded that the normal meaning of recycled zinc anode with increasing melting temperature can produce zinc anode better than original zinc anode and can be used as cathode protection on board ships. This research can assist in the management of used zinc anode waste, the supply of zinc anodes for consumers at relatively low prices, and recommendations of using zinc anodes for the prevention of corrosion on board ship.

  15. Enhanced electrical power generation using flame-oxidized stainless steel anode in microbial fuel cells and the anodic community structure.

    Science.gov (United States)

    Yamashita, Takahiro; Ishida, Mitsuyoshi; Asakawa, Shiho; Kanamori, Hiroyuki; Sasaki, Harumi; Ogino, Akifumi; Katayose, Yuichi; Hatta, Tamao; Yokoyama, Hiroshi

    2016-01-01

    Carbon-based materials are commonly used as anodes in microbial fuel cells (MFCs), whereas metal and metal-oxide-based materials are not used frequently because of low electrical output. Stainless steel is a low-cost material with high conductivity and physical strength. In this study, we investigated the power generation using flame-oxidized (FO) stainless steel anodes (SSAs) in single-chambered air-cathode MFCs. The FO-SSA performance was compared to the performance of untreated SSA and carbon cloth anode (CCA), a common carbonaceous electrode. The difference in the anodic community structures was analyzed using high-throughput sequencing of the V4 region in 16S rRNA gene. Flame oxidation of SSA produced raised node-like sites, predominantly consisting of hematite (Fe2O3), on the surface, as determined by X-ray diffraction spectroscopy. The flame oxidation enhanced the maximum power density (1063 mW/m(2)) in MFCs, which was 184 and 24 % higher than those for untreated SSA and CCA, respectively. The FO-SSA exhibited 8.75 and 2.71 times higher current production than SSA and CCA, respectively, under potentiostatic testing conditions. Bacteria from the genus Geobacter were detected at a remarkably higher frequency in the biofilm formed on the FO-SSA (8.8-9.2 %) than in the biofilms formed on the SSA and CCA (0.7-1.4 %). Bacterial species closely related to Geobacter metallireducens (>99 % identity in the gene sequence) were predominant (93-96 %) among the genus Geobacter in the FO-SSA biofilm, whereas bacteria with a 100 % identity to G. anodireducens were abundant (>55 %) in the SSA and CCA biofilms. This is the first demonstration of power generation using an FO-SSA in MFCs. Flame oxidation of the SSA enhances electricity production in MFCs, which is higher than that with the common carbonaceous electrode, CCA. The FO-SSA is not only inexpensive but also can be prepared using a simple method. To our knowledge, this study reveals, for the first time, that

  16. Silicon oxide based high capacity anode materials for lithium ion batteries

    Science.gov (United States)

    Deng, Haixia; Han, Yongbong; Masarapu, Charan; Anguchamy, Yogesh Kumar; Lopez, Herman A.; Kumar, Sujeet

    2017-03-21

    Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.

  17. Microscopic observation of pattern attack by aggressive ions on finished surface of aluminium alloy sacrificial anode

    International Nuclear Information System (INIS)

    Zaifol Samsu; Muhammad Daud; Siti Radiah Mohd Kamarudin; Nur Ubaidah Saidin; Azali Muhammad; Mohd Shaari Ripin; Rusni Rejab; Mohd Shariff Sattar

    2010-01-01

    This paper presents the results of a microscopic observation on submerged finished surface of aluminium alloy sacrificial anode. Experimental tests were carried out on polished surface aluminium anode exposed to seawater containing aggressive ions in order to observe of pattern corrosion attack on corroding surface of anode. Results have shown, at least under the present testing condition, that surface of sacrificial anode were attack by an aggressive ion such as chloride along grain boundaries. In addition, results of microanalysis showed that the corrosion products on surface of aluminium alloy have Al, Zn and O element for all sample and within the pit was consists of Al, Zn, O and Cl element. (author)

  18. Raman spectroscopy used for structural investigations of anodically formed ZrO2

    International Nuclear Information System (INIS)

    Koneska, Zagorka; Arsova, Irena

    2003-01-01

    The structure of the oxide formed on Zr(99% + Hf) with anodic oxidation at different potentials in 1 mol/dm 3 H 3 PO 4 and 2 mol/dm 3 KOH solutions were investigated using Raman spectroscopy. Normally the anodic oxides of Zr form only crystals. Under certain circumstances, amorphous anodic ZrO 2 can be observed. Amorphous phase is observed for the anodically formed zirconium oxides in H 3 PO 4 . The oxide formed in KOH at potential of 80 V, where sparks appears on the Zr electrode showed crystalline structure. (Original)

  19. Design and numerical simulation of the electromagnetic field of linear anode layer ion source

    International Nuclear Information System (INIS)

    Wang Lisheng; Tang Deli; Cheng Changming

    2006-01-01

    The principle of anode layer ion source for etching, pre-cleaning and ion beam assisted deposition was described. The influence of the magnetic field on the performance of anode layer ion source was analyzed. Design of the magnetic loop for the linear anode layer ion source was given. The electromagnetic field distribution of the ion source was simulated by means of ANSYS code and the simulation results were in agreement with experimental ones. The numerical simulation results of the electromagnetic field are useful for improving the anode layer ion source. (authors)

  20. Effect of Anode Structure on the Plasma Jet Characteristics of Arcjet Thruster

    Directory of Open Access Journals (Sweden)

    Du Zhenzhi

    2015-01-01

    Full Text Available In order to study the effects of anode geometry on volt-ampere characteristics and plasma jet characteristics of the arcjet thruster, the arcjet thruster flow characteristics were simulated. Through numerical simulation, the velocity field and temperature field of thruster were calculated, and the volt-ampere characteristics were obtained at different anode geometry. The calculation results show that the influence of the anode throat diameter was the most obvious, compared to the influence of the anode throat length and compression angle on volt-ampere characteristics and plasma jet characteristic of the arcjet thruster.

  1. Exploring As-Cast PbCaSn-Mg Anodes for Improved Performance in Copper Electrowinning

    Science.gov (United States)

    Yuwono, Jodie A.; Clancy, Marie; Chen, Xiaobo; Birbilis, Nick

    2018-03-01

    Lead calcium tin (PbCaSn) alloys are the common anodes used in copper electrowinning (Cu EW). Given a large amount of energy consumed in Cu EW process, anodes with controlled oxygen evolution reaction (OER) kinetics and a lower OER overpotential are advantageous for reducing the energy consumption. To date, magnesium (Mg) has never been studied as an alloying element for EW anodes. As-cast PbCaSn anodes with the addition of Mg were examined herein, revealing an improved performance compared to that of the industrial standard PbCaSn anode. The alloy performances in the early stages of anode life and passivation were established from electrochemical studies which were designed to simulate industrial Cu EW process. The 24-hour polarization testing revealed that the Mg alloying depolarizes the anode potential up to 80 mV; thus, resulting in a higher Cu EW efficiency. In addition, scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the alteration of the alloy microstructure and the corresponding interfacial reactions contribute to the changes of the anode electrochemical performances. The present study reveals for the first time the potency of Mg alloying in reducing the overpotential of PbCaSn anode.

  2. The impact of anode acclimation strategy on microbial electrolysis cell treating hydrogen fermentation effluent

    DEFF Research Database (Denmark)

    Li, Xiaohu; Zhang, Ruizhe; Qian, Yawei

    2017-01-01

    The impact of different anode acclimation methods for enhancing hydrogen production in microbial electrolysis cell (MEC) was investigated in this study. The anodes were first acclimated in microbial fuel cells using acetate, butyrate and corn stalk fermentation effluent (CSFE) as substrate before......). The current density (480 ± 11 A/m3) and hydrogen production rate (4.52 ± 0.13 m3/m3/d) with the anode pre-acclimated with butyrate were also higher that another two reactors. These results demonstrated that the anode biofilm pre-acclimated with butyrate has significant advantages in CSFE treatment and could...

  3. From alumina nanopores to nanotubes: dependence on the geometry of anodization system.

    Science.gov (United States)

    Feil, Adriano F; da Costa, Marlla V; Migowski, Pedro; Dupont, Jaïrton; Teixeira, Sérgio R; Amaral, Lívio

    2011-03-01

    The Conventional anodization of commercial aluminum sheets with a phosphoric acid electrolyte was employed for the preparation of alumina nanopore and/or nanotube structures. Modifying the system geometry (the ratio of platinum to aluminum electrode areas) controlled the nature of the anodization process (mild to hard). Nanotube formation was observed after low temperature preferential chemical etching of the defective corners of the hexagonal alumina cells using the same solution from the anodization process. Electrode geometry can be used to combine mild and hard anodization with low temperature etching to tune the alumina morphology from 100% nanopores to 100% nanotubos coverage.

  4. Microstructure and optical appearance of anodized friction stir processed Al - Metal oxide surface composites

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Bordo, Kirill

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate Ti, Y and Ce oxide powders into the surface of an Aluminium alloy. The FSP processed surface composite was subsequently anodized with an aim to develop optical effects in the anodized layer owing to the presence of incorporated...... oxide particles which will influence the scattering of light. This paper presents the investigations on relation between microstructure of the FSP zone and optical appearance of the anodized layer due to incorporation of metal oxide particles and modification of the oxide particles due to the anodizing...

  5. Formation of self-organized nanoporous anodic oxide from metallic gallium.

    Science.gov (United States)

    Pandey, Bipin; Thapa, Prem S; Higgins, Daniel A; Ito, Takashi

    2012-09-25

    This paper reports the formation of self-organized nanoporous gallium oxide by anodization of solid gallium metal. Because of its low melting point (ca. 30 °C), metallic gallium can be shaped into flexible structures, permitting the fabrication of nanoporous anodic oxide monoliths within confined spaces like the inside of a microchannel. Here, solid gallium films prepared on planar substrates were employed to investigate the effects of anodization voltage (1, 5, 10, 15 V) and H(2)SO(4) concentration (1, 2, 4, 6 M) on anodic oxide morphology. Self-organized nanopores aligned perpendicular to the film surface were obtained upon anodization of gallium films in ice-cooled 4 and 6 M aqueous H(2)SO(4) at 10 and 15 V. Nanopore formation could be recognized by an increase in anodic current after a current decrease reflecting barrier oxide formation. The average pore diameter was in the range of 18-40 nm with a narrow diameter distribution (relative standard deviation ca. 10-20%), and was larger at lower H(2)SO(4) concentration and higher applied voltage. The maximum thickness of nanoporous anodic oxide was ca. 2 μm. In addition, anodic formation of self-organized nanopores was demonstrated for a solid gallium monolith incorporated at the end of a glass capillary. Nanoporous anodic oxide monoliths formed from a fusible metal will lead to future development of unique devices for chemical sensing and catalysis.

  6. The Potential of Acousto-Ultrasonic Techniques for Inspection of Baked Carbon Anodes

    Directory of Open Access Journals (Sweden)

    Moez Ben Boubaker

    2016-07-01

    Full Text Available High quality baked carbon anodes contribute to the optimal performance of aluminum reduction cells. However, the currently decreasing quality and increasing variability of anode raw materials (coke and pitch make it challenging to manufacture the anodes with consistent overall quality. Intercepting faulty anodes (e.g., presence of cracks and pores before they are set in reduction cells and deteriorate their performance is therefore important. This is a difficult task, even in modern and well-instrumented anode plants, because lab testing using core samples can only characterize a small proportion of the anode production due to the costly, time-consuming, and destructive nature of the analytical methods. In addition, these results are not necessarily representative of the whole anode block. The objective of this work is to develop a rapid and non-destructive method for quality control of baked anodes using acousto-ultrasonic (AU techniques. The acoustic responses of anode samples (sliced sections were analyzed using a combination of temporal features computed from AU signals and principal component analysis (PCA. The AU signals were found sensitive to pores and cracks and were able to discriminate the two types of defects. The results were validated qualitatively by submitting the samples to X-ray Computed Tomography (CT scan.

  7. Effects of laser irradiation on machined and anodized titanium disks.

    Science.gov (United States)

    Park, Ji-Hye; Heo, Seong-Joo; Koak, Jai-Young; Kim, Seong-Kyun; Han, Chong-Hyun; Lee, Joo-Hee

    2012-01-01

    Although the laser has become one of the most commonly used tools for implant dentistry, research is lacking on whether or not the laser causes any changes on the surface of titanium (Ti) implants. The present study analyzed the morphology, composition, crystal structure, and surface roughness changes of machined and anodized Ti surfaces, irradiated with erbium chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG), erbium-doped yttrium-aluminum-garnet (Er:YAG), and carbon dioxide (CO2) lasers. Seventy-two Ti disks were fabricated by machining commercially pure Ti (grade 3); 36 of them were anodized at 300 V. The disks were irradiated with Er,Cr:YSGG, Er:YAG, and CO2 lasers at five different powers (1, 2, 3, 4, and 5 W). The irradiated disks were examined with scanning electron microscopy, electron probe microanalysis, x-ray diffractometry, and optical interferometry. Surface changes were observed on both types of Ti surfaces irradiated with the Er,Cr:YSGG laser when more than 3 W of power were applied. Surface changes were observed on both types of Ti surfaces when irradiated with the Er:YAG laser with more than 2 W of power. No change was observed when the disks were irradiated with the CO2 laser. The proportion of oxide in the machined Ti disk increased after the application of the Er,Cr:YSGG or Er:YAG laser. In the anodized Ti disk, the anatase peak intensity decreased and the rutile peak intensity increased after laser irradiation. The irradiated Ti disks were significantly rougher than the nonirradiated Ti disks. The Er:YAG and Er,Cr:YSGG laser resulted in surface changes on the Ti disks according to the power output. The CO2 laser did not affect the surface of the Ti disks, irrespective of the power output.

  8. Electrochemical degradation of clofibric acid in water by anodic oxidation

    International Nuclear Information System (INIS)

    Sires, Ignasi; Cabot, Pere Lluis; Centellas, Francesc; Garrido, Jose Antonio; Rodriguez, Rosa Maria; Arias, Conchita; Brillas, Enric

    2006-01-01

    Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical (·OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl 2 . Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with ·OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO 2 with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed

  9. Behaviour of polonium-210 during anode slimes processing

    International Nuclear Information System (INIS)

    Brown, S. A.

    1998-01-01

    Refinery slimes produced during the electrorefining of copper anodes often contain recoverable quantities of gold, silver and the platinum group metals, platinum and palladium. The treatment process selected to recover precious metals from the slimes depends on the concentration of other impurities. Polonium-210 will be present in the refinery slimes when uranium-bearing minerals (e.g. uraninite) are associated with the copper mineralogy. The production of pure precious metals from copper anode slimes containing polonium-210 involves a variety of steps including impurity removal, smelting to produce a dore metal and then refining. Gold and silver are recovered by electrorefining processes. Platinum group metals accumulate in the gold electrolyte and are recovered by precipitation. To ensure that specifications are met in the final products, it is necessary to identify and closely monitor where the impurities, including polonium-210, are partitioning during processing. Although measurement of polonium-210 activity using alpha spectrometry identifies relative amounts of the radionuclide in the various streams, it does not give any indication of the form it may be in. By studying the chemistry and deportment of its neighbours in the periodic table (Pb,Bi,Se and Te) it may be possible to make some conclusions regarding polonium-210 behaviour. Examination of the solid phases produced during anode slimes treatment were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Elemental analyses of solid and liquor streams were carried out using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES). This paper attempts to develop a relationship between the behaviour of polonium-210 and other impurities during precious metals recovery based on the results of these studies

  10. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, Robert W. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States)

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 - 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  11. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, R.W.; Muller, R.H.

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 {endash} 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  12. Behaviour of polonium-210 during anode slimes processing

    International Nuclear Information System (INIS)

    Brown, S.A.

    1998-01-01

    Refinery slimes produced during the electrorefining of copper anodes often contain recoverable quantities of gold, silver and the platinum group metals, platinum and palladium. The treatment process selected to recover precious metals from the slimes depends on the concentration of other impurities. Polonium 210 will be present in the refinery slimes when uranium-bearing minerals (eg. uraninite) are associated with the copper mineralogy. The production of pure precious metals from copper anode slimes containing polonium-210 involves a variety of steps including impurity removal smelting to produce a dore metal and then refining. Gold and silver are recovered by electrorefining processes. Platinum group metals accumulate in the gold electrolyte and are recovered by precipitation To ensure that specifications are met in the final products, it is necessary to identify and closely monitor where the impurities, including polonium-210, are partitioning during processing. Although measurement of polonium-210 activity using alpha spectrometry identifies relative amounts of the radionuclide in the various streams, it does not give any indication of the form it may be in. By studying the chemistry and deportment of its neighbours in the periodic table (Pb, Bi, Se and Te) it may be possible to make some conclusions regarding polonium-210 behaviour. Examination of the solid phases produced during anode slimes treatment were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Elemental analyses of solid and liquor streams were carried out using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES). This paper attempts to develop a relationship between the behaviour of polonium-210 and other impurities during precious metals recovery based on the results of these studies. (author). 5 refs., 4 tabs

  13. High capacity anode materials for lithium ion batteries

    Science.gov (United States)

    Lopez, Herman A.; Anguchamy, Yogesh Kumar; Deng, Haixia; Han, Yongbon; Masarapu, Charan; Venkatachalam, Subramanian; Kumar, Suject

    2015-11-19

    High capacity silicon based anode active materials are described for lithium ion batteries. These materials are shown to be effective in combination with high capacity lithium rich cathode active materials. Supplemental lithium is shown to improve the cycling performance and reduce irreversible capacity loss for at least certain silicon based active materials. In particular silicon based active materials can be formed in composites with electrically conductive coatings, such as pyrolytic carbon coatings or metal coatings, and composites can also be formed with other electrically conductive carbon components, such as carbon nanofibers and carbon nanoparticles. Additional alloys with silicon are explored.

  14. The nature of conducting materials by anodic coupling of pyrene

    Energy Technology Data Exchange (ETDEWEB)

    Zotti, G.; Schiavon, G. (Ist. di Polarografia ed Elettrochimica Preparativa, Consiglio Nazionale delle Ricerche, Padua (Italy))

    1992-05-01

    Polypyrenes from anodic coupling of pyrene in acetonitrile and 1,2-dichloroethane have been identified as the 1,1'-coupled dimer and tetramer, respectively, on the basis of electrochemical analysis and IR, UV-Vis and mass spectroscopies. Bipyrene and tetrapyrene are reversibly reduced at -2.27 and -2.15 V versus Ag/Ag{sup +}, respectively. Their electrochemical oxidation (at 0.96 and 0.87 V) is followed by further polymerization and ultimate degradation whereas iodine doping of tetrapyrene leads reversibly to a conducting adduct (6x10{sup -3} S/cm). (orig.).

  15. Use of Both Anode and Cathode Reactions in Wastewater Treatment

    Science.gov (United States)

    Brillas, Enric; Sirés, Ignasi; Cabot, Pere LluíS.

    Here, we describe the fundamentals, laboratory experiments, and environmental applications of indirect electrooxidation methods based on H2O2 electrogeneration such as electro-Fenton, photoelectro-Fenton and peroxicoagulation for the treatment of acidic wastewaters containing toxic and recalcitrant organics. These methods are electrochemical advanced oxidation processes that can be used in divided and undivided electrolytic cells in which pollutants are oxidized by hydroxyl radical (•OH) produced from anode and/or cathode reactions. H2O2 is generated from the two-electron reduction of O2 at reticulated vitreous carbon, graphite, carbon-felt, and O2-diffusion cathodes. The most usual method is electro-Fenton where Fe2 + added to the wastewater reacts with electrogenerated H2O2 to yield •OH and Fe3 + from Fenton's reaction. An advantage of this technique is that Fe2 + is continuously regenerated from cathodic reduction of Fe3 +. The characteristics of different electro-Fenton systems where pollutants are simultaneously destroyed by •OH formed in the medium from Fenton's reaction and at the anode surface from water oxidation are explained. The effect of the anode [Pt or boron-doped diamond (BDD)] and cathode (carbon-felt or O2-diffusion) on the degradation rate of persistent industrial by-products, herbicides, pharmaceuticals, dyes, etc. is examined. Initial pollutants react much more rapidly with •OH formed in the medium and their degradation sequences are discussed from aromatic intermediates and finally short aliphatic acids are detected. The synergetic positive catalytic effect of Cu2 + on the electro-Fenton process is evidenced. The photoelectro-Fenton method involves the irradiation of the wastewater with UVA light that rapidly photodecomposes complexes of Fe3 + with final carboxylic acids enhancing total decontamination. The peroxicoagulation method uses a sacrificial Fe anode that is continuously oxidized to Fe2 + and organics are either mineralized

  16. Battery designs with high capacity anode materials and cathode materials

    Science.gov (United States)

    Masarapu, Charan; Anguchamy, Yogesh Kumar; Han, Yongbong; Deng, Haixia; Kumar, Sujeet; Lopez, Herman A.

    2017-10-03

    Improved high energy capacity designs for lithium ion batteries are described that take advantage of the properties of high specific capacity anode active compositions and high specific capacity cathode active compositions. In particular, specific electrode designs provide for achieving very high energy densities. Furthermore, the complex behavior of the active materials is used advantageously in a radical electrode balancing design that significantly reduced wasted electrode capacity in either electrode when cycling under realistic conditions of moderate to high discharge rates and/or over a reduced depth of discharge.

  17. Silicene: A Promising Anode for Lithium-Ion Batteries.

    Science.gov (United States)

    Zhuang, Jincheng; Xu, Xun; Peleckis, Germanas; Hao, Weichang; Dou, Shi Xue; Du, Yi

    2017-12-01

    Silicene, a single-layer-thick silicon nanosheet with a honeycomb structure, is successfully fabricated by the molecular-beam-epitaxy (MBE) deposition method on metallic substrates and by the solid-state reaction method. Here, recent progress on the features of silicene that make it a prospective anode for lithium-ion batteries (LIBs) are discussed, including its charge-carrier mobility, chemical stability, and metal-silicene interactions. The electrochemical performance of silicene is reviewed in terms of both theoretical predictions and experimental measurements, and finally, its challenges and outlook are considered. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Electrodeposition of nickel onto steel using a soluble mobile anode

    International Nuclear Information System (INIS)

    Petit, G.S.; Wright, R.R.

    1978-04-01

    During the Cascade Improvement Program (CIP), a number of component parts that have been in service for many years will be reused. Many of these parts will have exposed steel from loss of nickel plate or mechanical damage. A good method is needed to patch small areas of exposed steel with electroplated nickel to inhibit the corrosive attack of uranium hexafluoride (UF 6 ) on the steel. A method to patch bare plate steel with nickel, using a mobile soluble anode, has been developed by the K-25 Technical Services Division. This report describes the method and presents test results of coupons plated by the method

  19. Electrochemically replicated smooth aluminum foils for anodic alumina nanochannel arrays

    International Nuclear Information System (INIS)

    Biring, Sajal; Tsai, K-T; Sur, Ujjal Kumar; Wang, Y-L

    2008-01-01

    A fast electrochemical replication technique has been developed to fabricate large-scale ultra-smooth aluminum foils by exploiting readily available large-scale smooth silicon wafers as the masters. Since the adhesion of aluminum on silicon depends on the time of surface pretreatment in water, it is possible to either detach the replicated aluminum from the silicon master without damaging the replicated aluminum and master or integrate the aluminum film to the silicon substrate. Replicated ultra-smooth aluminum foils are used for the growth of both self-organized and lithographically guided long-range ordered arrays of anodic alumina nanochannels without any polishing pretreatment

  20. Parallel-plate avalanche detectors with anode wire grids

    CERN Document Server

    Sanabria, J C; Cetina, C; Cole, P L; Dodge, W R; Nedorezov, V G; Sudov, A S; Kezerashvili, G Ya

    2000-01-01

    A fission-fragment detection system was designed and built at The George Washington University, to be used in photofission experiments at the Saskatchewan Accelerator Laboratory and the Jefferson Laboratory. The fission fragments were detected using parallel-plate avalanche detectors with anode wire grids. An array of several target-detector pairs was mounted inside a low-pressure reaction chamber. The results of calibrations of the detectors using a sup 2 sup 5 sup 2 Cf source and their performance with a bremsstrahlung photon beam during the experiments are presented.

  1. Anodic behavior of nickel alloys in media containing bicarbonate ions

    International Nuclear Information System (INIS)

    Zadorozne, N.S; Carranza, R. M.; Giordano, C.M.

    2011-01-01

    Alloy 22 has been designed to resist corrosion in oxidizing and reducing conditions. Thanks to these properties it is considered a possible candidate for the fabrication of containers of high-level radioactive waste. Since the containers provide services in natural environments characterized by multi-ionic solutions, it is estimated they could suffer three types of deterioration: general corrosion, localized corrosion (specifically crevice corrosion) and stress corrosion cracking (SCC). It has been confirmed that the presence of bicarbonate and chloride ions is required in order to produce cracking. It has also been determined that the susceptibility to SCC could be related to the occurrence of an anodic peak in the polarization curves in these media potentials below trans-passivity. The aim of this work is to study the anodic behavior of Alloy 22 in different media containing bicarbonate and chloride ions in various concentrations and temperatures and compare the results with other alloys containing nickel, and relate them to the susceptibility to stress corrosion cracking in a future job. Polarization curves were made on alloy 22 (Ni-Cr-Mo), 600 (Ni- Cr-Fe), 800h (Ni-Fe- Cr) and 201 (Ni commercially pure) in the following environments: 1.148 mol/L NaHCO 3 , 1.148 mol/L NaHCO 3 + 1 mol/L NaCl, 1.148 mol/L NaHCO 3 + 0.1 mol/L NaCl. The tests were performed at the following temperatures: 90°C, 75°C, 60°C and 25°C. It was found that alloy 22 has a current peak in the anodic domain at potentials below trans-passivity between 200 and 300 m VECS, when the test temperature was 90°C. The potential, at which this peak occurred, increased with decreasing temperature. Also there was a variation of the peak with the composition of the solution. When bicarbonate ions were added to a solution containing chloride ions, the peak potential shifted to higher current densities, depending on the concentration of added chloride ions. It was found that diminishing the content of

  2. Study of Operating Parameters for Accelerated Anode Degradation in SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    2017-01-01

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to demonstrate such exceptionally long lifetimes in ongoing R&D projects. Accelerated or compressed testing are alternative methods to obtain this. Activities in this area have been...... SOFC components as function of operating conditions. Electrochemical impedance data were collected on the fresh and long-term tested SOFCs and used to de-convolute the individual losses of single SOFC cell components – electrolyte, cathode and anode. The main findings include a time-dependent effect...

  3. Experimental study of anode processes in plasma arc cutting

    Czech Academy of Sciences Publication Activity Database

    Kavka, Tetyana; Chumak, Oleksiy; Šonský, Jiří; Heinrich, M.; Stehrer, T.; Pauser, H.

    2013-01-01

    Roč. 46, č. 6 (2013), 065202-065202 ISSN 0022-3727 R&D Projects: GA ČR GAP205/11/2070 Institutional support: RVO:61389021 ; RVO:61388998 Keywords : Arc cutting * anode attachment * pilot arc * steam plasma cutting * torch * fluctuations * JET Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (UT-L) Impact factor: 2.521, year: 2013 http://iopscience.iop.org/0022-3727/46/6/065202/pdf/0022-3727_46_6_065202.pdf

  4. Analysis of Anodes of Microbial Fuel Cells When Carbon Brushes Are Preheated at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Qiao Yang

    2017-10-01

    Full Text Available The anode electrode is one of the most important components in all microbial electrochemical technologies (METs. Anode materials pretreatment and modification have been shown to be an effective method of improving anode performance. According to mass loss analysis during carbon fiber heating, five temperatures (300, 450, 500, 600, and 750 °C were selected as the pre-heating temperatures of carbon fiber brush anodes. Microbial fuel cell (MFC reactors built up with these pre-heated carbon brush anodes performed with different power densities and Coulombic efficiencies (CEs. Two kinds of measuring methods for power density were applied, and the numerical values of maximum power densities diverged greatly. Reactors with 450 °C anodes, using both methods, had the highest power densities, and the highest CEs were found using 500 °C anode reactors. The surface elements of heat-treated carbon fibers were analyzed using X-ray photoelectron spectra (XPS, and C, O, and N were the main constituents of the carbon fiber. There were four forms of N1s at the surface of the polyacrylonitrile (PAN-based carbon fiber, and their concentrations were different at different temperature samples. The microbial community of the anode surface was analyzed, and microbial species on anodes from every sample were similar. The differences in anode performance may be caused by mass loss and by the surface elements. For carbon brush anodes used in MFCs or other BESs, 450–500 °C preheating was the most suitable temperature range in terms of the power densities and CEs.

  5. Altering Anode Thickness To Improve Power Production in Microbial Fuel Cells with Different Electrode Distances

    KAUST Repository

    Ahn, Yongtae

    2013-01-17

    A better understanding of how anode and separator physical properties affect power production is needed to improve energy and power production by microbial fuel cells (MFCs). Oxygen crossover from the cathode can limit power production by bacteria on the anode when using closely spaced electrodes [separator electrode assembly (SEA)]. Thick graphite fiber brush anodes, as opposed to thin carbon cloth, and separators have previously been examined as methods to reduce the impact of oxygen crossover on power generation. We examined here whether the thickness of the anode could be an important factor in reducing the effect of oxygen crossover on power production, because bacteria deep in the electrode could better maintain anaerobic conditions. Carbon felt anodes with three different thicknesses were examined to see the effects of thicker anodes in two configurations: widely spaced electrodes and SEA. Power increased with anode thickness, with maximum power densities (604 mW/m 2, 0.32 cm; 764 mW/m2, 0.64 cm; and 1048 mW/m2, 1.27 cm), when widely spaced electrodes (4 cm) were used, where oxygen crossover does not affect power generation. Performance improved slightly using thicker anodes in the SEA configuration, but power was lower (maximum of 689 mW/m2) than with widely spaced electrodes, despite a reduction in ohmic resistance to 10 Ω (SEA) from 51-62 Ω (widely spaced electrodes). These results show that thicker anodes can work better than thinner anodes but only when the anodes are not adversely affected by proximity to the cathode. This suggests that reducing oxygen crossover and improving SEA MFC performance will require better separators. © 2012 American Chemical Society.

  6. Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium

    Energy Technology Data Exchange (ETDEWEB)

    Amin Yavari, S., E-mail: s.aminyavari@tudelft.nl [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Chai, Y.C. [Prometheus, Division of Skeletal Tissue Engineering, Bus 813, O& N1, Herestraat 49, KU Leuven, 3000 Leuven (Belgium); Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, Bus 813, O& N1, Herestraat 49, KU Leuven, 3000 Leuven (Belgium); Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Böttger, A.J. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Wauthle, R. [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); 3D Systems — LayerWise NV, Grauwmeer 14, 3001 Leuven (Belgium); Schrooten, J. [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 — PB2450, B-3001 Heverlee (Belgium); Weinans, H. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Department of Orthopedics and Dept. Rheumatology, UMC Utrecht, Heidelberglaan100, 3584CX Utrecht (Netherlands); Zadpoor, A.A. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2015-06-01

    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20 V anodizing time: 30 min to 3 h) are used for anodizing porous titanium structures that were later heat treated at 500 °C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55 nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500 °C improve the cell culture response of porous titanium

  7. Some features of the anodic dissolution of platinized titanium anodes and of oxygen evolution in the electrolysis of dilute sodium chloride solutions

    International Nuclear Information System (INIS)

    Mikhailova, L.A.; Khodkevich, S.D.; Yakimenko, L.M.; Ivanova, M.I.; Ogloblina, I.P.

    1988-01-01

    Radioactivity measurements and gas chromatography were used to study and compare features of anodic dissolution of platinum and platinum coatings from platinized titanium anodes, and oxygen evolution as functions of the electrolysis parameters of current density, temperature, and concentration in electrolytes with low sodium chloride content. Quantities representing the ratio of anodic platinum dissolution rates and oxygen evolution were calculated. The results showed that analogies exist between rates of platinum dissolution, and oxygen evolution but these ratios are not constant when the electrolysis parameters are varied within wide limits. A correlation was observed for dilute solutions and electrolysis temperatures enabling one to estimate the corrosion rates of platinized titanium anodes from the oxygen content of the electrolytic gas

  8. Acid blue 29 decolorization and mineralization by anodic oxidation with a cold gas spray synthesized Sn-Cu-Sb alloy anode.

    Science.gov (United States)

    do Vale-Júnior, Edilson; Dosta, Sergi; Cano, Irene Garcia; Guilemany, Josep Maria; Garcia-Segura, Sergi; Martínez-Huitle, Carlos Alberto

    2016-04-01

    The elevated cost of anodic materials used in the anodic oxidation for water treatment of effluents undermines the real application of these technologies. The study of novel alternative materials more affordable is required. In this work, we report the application of Sn-Cu-Sb alloys as cheap anodic material to decolorize azo dye Acid Blue 29 solutions. These anodes have been synthesized by cold gas spray technologies. Almost complete decolorization and COD abatement were attained after 300 and 600 min of electrochemical treatment, respectively. The influence of several variables such as supporting electrolyte, pH, current density and initial pollutant concentration has been investigated. Furthermore, the release and evolution of by-products was followed by HPLC to better understand the oxidative power of Sn-Cu-Sb electrodes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Graphene composites as anode materials in lithium-ion batteries

    Science.gov (United States)

    Mazar Atabaki, M.; Kovacevic, R.

    2013-03-01

    Since the world of mobile phones and laptops has significantly altered by a big designer named Steve Jobs, the electronic industries have strived to prepare smaller, thinner and lower weight products. The giant electronic companies, therefore, compete in developing more efficient hardware such as batteries used inside the small metallic or polymeric frame. One of the most important materials in the production lines is the lithium-based batteries which is so famous for its ability in recharging as many times as a user needs. However, this is not an indication of being long lasted, as many of the electronic devices are frequently being used for a long time. The performance, chemistry, safety and above all cost of the lithium ion batteries should be considered when the design of the compounds are at the top concern of the engineers. To increase the efficiency of the batteries a combination of graphene and nanoparticles is recently introduced and it has shown to have enormous technological effect in enhancing the durability of the batteries. However, due to very high electronic conductivity, these materials can be thought of as preparing the anode electrode in the lithiumion battery. In this paper, the various approaches to characterize different types of graphene/nanoparticles and the process of preparing the anode for the lithium-ion batteries as well as their electrical properties are discussed.

  10. Novel Anode Catalyst for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    S. Basri

    2014-01-01

    Full Text Available PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni and iron (Fe. Multiwalled carbon nanotubes (MWCNTs are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX, X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, and X-ray photoelectron spectroscopy (XPS, are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR. The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2–5 nm PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g−1 catalyst.

  11. Pulsed klystrons with feedback controlled mod-anode modulators

    Energy Technology Data Exchange (ETDEWEB)

    Reass, William A [Los Alamos National Laboratory; Baca, David M [Los Alamos National Laboratory; Jerry, Davis L [Los Alamos National Laboratory; Rees, Daniel E [Los Alamos National Laboratory

    2009-01-01

    This paper describes a fast rise and fall, totem-pole mod-anode modulators for klystron application. Details of these systems as recently installed utilizing a beam switch tube ''on-deck'' and a planar triode ''off-deck'' in a grid-catch feedback regulated configuration will be provided. The grid-catch configuration regulates the klystron mod-anode voltage at a specified set-point during switching as well as providing a control mechanism that flat-top regulates the klystron beam current during the pulse. This flat-topped klystron beam current is maintained while the capacitor bank droops. In addition, we will review more modern on-deck designs using a high gain, high voltage planar triode as a regulating and switching element. These designs are being developed, tested, and implemented for the Los Alamos Neutron Science Center (LANSCE) accelerator refurbishment project, ''LANSCE-R''. An advantage of the planar triode is that the tube can be directly operated with solid state linear components and provides for a very compact design. The tubes are inexpensive compared to stacked semiconductor switching assemblies and also provide a linear control capability. Details of these designs are provided as well as operational and developmental results.

  12. Hydrogen anode for nitrate waste destruction. Revision 2

    International Nuclear Information System (INIS)

    Hobbs, D.T.; Kalu, E.E.; White, R.E.

    1996-01-01

    Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na 2 SO 4 /H 2 SO 4 anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. This could result in a substantial savings in the operation of a nitrate destruction cell

  13. A physical model of Direct Methanol Fuel Cell anode impedance

    Science.gov (United States)

    Zago, M.; Casalegno, A.

    2014-02-01

    In the present work a physically based model of direct methanol fuel cell anode impedance has been developed and validated at different operating current densities. The proposed model includes the two-phase mass transport of both methanol and water through diffusion and catalyst layers and the methanol oxidation reaction involving CO adsorbed intermediate. Model simulations are in good quantitative agreement with experimental observations and permit to evaluate the origin of anode impedance features. Model results confirm that the high frequency 45° linear branch is caused by proton transport limitations within the catalyst layer and that the low frequency inductive behavior is due to surface coverage by CO reaction intermediate. Moreover model predictions elucidate the contribution to the impedance of mass transport phenomena through diffusion layer, that is relevant even at low current density and increases along the channel length. In particular liquid convective fluxes are considered as a process of pressure buildup and breakthrough at diffusion layer intersecting fibers, resulting in a discontinuous phenomenon. By means of this intermittent description it is possible to correctly reproduce mass transport limitations through diffusion layers, that manifest themselves as a second arch superimposed to the first one, peculiar of kinetic losses.

  14. Novel anode catalyst for direct methanol fuel cells.

    Science.gov (United States)

    Basri, S; Kamarudin, S K; Daud, W R W; Yaakob, Z; Kadhum, A A H

    2014-01-01

    PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS), are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV) is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA) tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR). The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2-5 nm) PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g(-1) catalyst.

  15. Realisation of an anode supported planar SOFC system

    Energy Technology Data Exchange (ETDEWEB)

    Buchkremer, H.P.; Stoever, D. [Institut fuer Werkstoffe der Energietechnik, Juelich (Germany); Diekmann, U. [Zentralabteilung Technologie, Juelich (Germany)] [and others

    1996-12-31

    Lowering the operating temperature of S0FCs to below 800{degrees}C potentially lowers production costs of a SOFC system because of a less expensive periphery and is able to guarantee sufficient life time of the stack. One way of achieving lower operating temperatures is the development of new high conductive electrolyte materials. The other way, still based on state-of-the-art material, i.e. yttria-stabilized zirconia (YSZ) electrolyte, is the development of a thin film electrolyte concept. In the Forschungszentrum Julich a program was started to produce a supported planar SOFC with an YSZ electrolyte thickness between 10 to 20 put. One of the electrodes, i.e. the anode, was used as support, in order not to increase the number of components in the SOFC. The high electronic conductivity of the anode-cermet allows the use of relatively thick layers without increasing the cell resistance. An additional advantage of the supported planar concept is the possibility to produce single cells larger than 10 x 10 cm x cm, that is with an effective electrode cross area of several hundred cm{sup 2}.

  16. Protection of Lithium (Li) Anodes Using Dual Phase Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Mikhaylik, Yuriy [Sion Power Corporation, Tucson, AZ (United States)

    2014-09-30

    Sion Power focused on metallic lithium anode protection, employing the Dual-Phase Electrolyte approach. The objective of this project was to develop a unique electrolyte providing two liquid phases having good Li+ conductivity, self-partitioning and immiscibility, serving separately the cathode and anode electrodes. This Dual-Phase Electrolyte was combined with thin film multi-layer, physical barrier membranes developed partially under a separate ARPA-E funded project. All these protective structures were stabilized by externally applied pressure. This strategy was used for Li-S cells. The development directly addressed cell safety, particularly higher thermal stability, while also allowing higher energies and cycle life. Safety tests showed that 100% of cells with Dual-Phase Electrolyte were intact and did not exhibit thermal runaway up to 178 °C and thus met the project objective of increasing the runaway temperature to >165°C. Cells also passed cycling at USABC Dynamic Stress Test conditions developed for Electric Vehicle applications and generated specific energy > 300 Wh/kg.

  17. Multi-Anode Photomultplier (MAPMT) readout for High Granularity Calorimeters

    CERN Document Server

    Mkrtchyan, Tigran; The ATLAS collaboration

    2017-01-01

    Hadron calorimeter high performance in jet sub-structure measurements can be achieved for objects with $p_{T}$ greater than 1 TeV if the readout geometry is finely segmented in $\\Delta\\eta \\times \\Delta\\phi$. A feasibility study to increase the readout granularity of TileCal, the central hadron calorimeter of the ATLAS detector, is presented. We show a preliminary study exploring the possibility to increase by a factor 4 the present readout granularity of the inner layer cells of TileCal (0.1->0.025 in $\\Delta\\eta$) and to split into two layers the intermediate section of TileCal. The proposed solution is designed to cope with mechanical and readout bandwidth and power constraints. Assuming that the mechanics of the Tile modules cannot be changed, Multi-Anode PMTs with same boundary geometry of the present single-anode PMTs are considered to readout WLS bers, ideally one per pixel, carrying the signals from the individual scintillating tiles of each detector cells. The discussed challenges of the design are: ...

  18. Anodic Fabrication of Ti-Nb-Zr-O Nanotube Arrays

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    2014-01-01

    Full Text Available Highly ordered Ti-Nb-Zr-O nanotube arrays were fabricated through pulse anodic oxidation of Ti-Nb-Zr alloy in 1 M NaH2PO4 containing 0.5 wt% HF electrolytes. The effect of anodization parameters and Zr content on the microstructure and composition of Ti-Nb-Zr-O nanotubes was investigated using a scanning electron microscope equipped with energy dispersive X-ray analysis. It was found that length of the Ti-Nb-Zr-O nanotubes increased with increase of Zr contents. The diameter and the length of Ti-Nb-Zr-O nanotubes could be controlled by pulse voltage. XRD analysis of Ti-Nb-Zr-O samples annealed at 500°C in air indicated that the (101 diffraction peaks shifted from 25.78° to 25.05° for annealed Ti-Nb-Zr-O samples with different Zr contents because of larger lattice parameter of Ti-Nb-Zr-O compared to that of undoped TiO2.

  19. A conducting polymer/ferritin anode for biofuel cell applications

    International Nuclear Information System (INIS)

    Inamuddin; Shin, Kwang Min; Kim, Sun I.; So, Insuk; Kim, Seon Jeong

    2009-01-01

    An enzyme anode for use in biofuel cells (BFCs) was constructed using an electrically connected bilayer based on a glassy carbon (GC) electrode immobilized with the conducting polymer polypyrrole (Ppy) as electron transfer enhancer, and with horse spleen ferritin protein (Frt) as electron transfer mediator. The surface-coupled redox system of nicotinamide adenine dinucleotide (NADH) catalyzed with diaphorase (Di) was used for the regeneration of NAD + in the inner layer and the NAD + -dependent enzyme catalyst glucose dehydrogenase (GDH) in the outer layer. The outer layer of the GC-Ppy-Frt-Di-NADH-GDH electrode effectively catalyzes the oxidation of glucose biofuel continuously; using the NAD + generated at the inner layer of the Di-catalyzed NADH redox system mediated by Frt and Ppy provides electrical communication with enhancement in electron transport. The electrochemical characteristics of the electrodes were investigated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). This anode provides a current density of 1.2 mA cm -2 in a 45 mM glucose solution and offers a good possibility for application in biofuel cells.

  20. The electronic structure of anodized and etched aluminum alloy surfaces

    Science.gov (United States)

    Mullins, W. M.; Averbach, B. L.

    1988-11-01

    Specimens of 6061 and 5052 aluminum alloys which had been anodized and etched by several commonly used procedures were examined by means of bias-reference X-ray photoelectron spectroscopy (XPS). The spectra were compared with those obtained from single crystals of pure aluminum oxides. The chemical shifts observed from the A12p surface oxide lines were interpreted as differences in the Fermi energy levels relative to those in the bulk oxide crystals, and the Fermi energy levels of the surface oxides were thus determined. Using an earlier experimental correlation obtained for values of the point of zero charge (pzc) with Fermi energy levels in aluminum oxide powders, a value of the pzc of the surface oxide was then determined. The surface exhibited the maximum alkalinity, pzc = 8.9, after a caustic etch, and the maximum acidity, pzc = 3.6, after a phosphoric acid anodizing treatment. The significance of these pzc values in the adhesive bonding of aluminum alloys is discussed.

  1. Characterization of proton exchange membrane fuel cell anode catalysts prepared by colloid method

    Energy Technology Data Exchange (ETDEWEB)

    Franco, E.G.; Dantas-Filho, P.L.; Burani, G.F. [Universidade de Sao Paulo (IEE/USP), Sao Paulo, SP (Brazil). Instituto de Eletrotecnica e Energia

    2009-07-01

    Full text: Anode catalysts for Proton Exchange Membrane Fuel Cell (PEMFC) were synthesized by the colloid method and their structure was investigated by transmission electron microscopy (TEM), energy dispersive analyses (EDS), X-ray Diffraction (XRD). The electrochemical behavior of the anode catalyst was analyzed by cyclic voltammetry (CV) and polarization curves (UxI). (author)

  2. Ni modified ceramic anodes for direct-methane solid oxide fuel cells

    Science.gov (United States)

    Xiao, Guoliang; Chen, Fanglin

    2016-01-19

    In accordance with certain embodiments of the present disclosure, a method for fabricating a solid oxide fuel cell is described. The method includes synthesizing a composition having a perovskite present therein. The method further includes applying the composition on an electrolyte support to form an anode and applying Ni to the composition on the anode.

  3. 40 CFR 413.40 - Applicability: Description of the anodizing subcategory.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability: Description of the anodizing subcategory. 413.40 Section 413.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 413.40 Applicability: Description of the anodizing subcategory. The provisions of this subpart apply...

  4. Effect of the anodization variables in the corrosion resistence of the zircaloy-4 tubes

    International Nuclear Information System (INIS)

    Figueiredo, M.E.

    1981-02-01

    The anodization effect in the oxidation of the zircaloy-4 in steam atmosphere at 10,06MPa was investigated. It was also studied how the voltage and the types of electrolytes at several values of pH affect the growing of the anodic oxide film and the performance of the zircaloy-4 in relation to corrosion. Anodizations of zircaloy-4 tubes have been made with voltages ranging from zero to 280V and using electrolytic solutions of Na 2 B 4 O 7 , CH 3 COOH and NaOH in the concentrations of 1,0N, 0,1N and 0,01N. After anodization, the tubes were oxidized in autoclave under steam at 400 0 C and 10,06 MPa during 3 and 14 days. The results show that the anodization inhibit the oxidation process of zircaloy-4, and that this protection increases with the voltage applied for film formation. The relationship between the weight gain after oxidation in autoclave and the anodization voltage is of the exponential type: (σM/A) sub(AC) = Ce sup(-DV). The observed relationship between the applied voltage and the weight gain due to anodization is of the linear type: (σM/A) sub(AN) = aV. Concerning the influence of different electrolytes, it was observed a similar behaviour between them with respect to the thickness of the anodic oxide and the weight gain of zircaloy-4 after the autoclave test. (Author) [pt

  5. Infiltration of commercially available, anode supported SOFC’s via inkjet printing

    NARCIS (Netherlands)

    Mitchell-Williams, T.B.; Tomov, R.I.; Saadabadi, S.A.; Krauz, M.; Purushothaman Vellayani, A.; Glowacki, B.A.; Kumar, R.V.

    2017-01-01

    Commercially available anode supported solid oxide fuel cells (NiO-8YSZ/8YSZ/LSCF- 20 mm in diameter) were anode infiltrated with gadolinium doped ceria (CGO) using a scalable drop-on-demand inkjet printing process. Cells were infiltrated with two different precursor solutions—water based or

  6. Full Ceramic Fuel Cells Based on Strontium Titanate Anodes, An Approach Towards More Robust SOFCs

    DEFF Research Database (Denmark)

    Holtappels, Peter; Irvine, J.T.S.; Iwanschitz, B.

    2013-01-01

    The persistent problems with Ni-YSZ cermet based SOFCs, with respect to redox stability and tolerance towards sulfur has stimulated the development of a full ceramic cell based on strontium titanate(ST)- based anodes and anode support materials, within the EU FCH JU project SCOTAS-SOFC. Three...

  7. Metal oxides and lithium alloys as anode materials for lithium-ion batteries

    CSIR Research Space (South Africa)

    Kebede, M

    2016-07-01

    Full Text Available -generation anode materials for lithium–ion batteries with high prospect of replacing graphite. Most of these anode materials have higher specific capacities between the range of 600-1000 mA h g(sup-1) compared with 340 mA h g(sup-1) of graphite. These high...

  8. Effect of pressure on behavior of anode attachment of dc arc plasma torch

    Czech Academy of Sciences Publication Activity Database

    Chumak, Oleksiy; Kopecký, Vladimír; Konrád, Miloš; Kavka, Tetyana; Hrabovský, Milan

    2005-01-01

    Roč. 9, č. 3 (2005), s. 391-400 ISSN 1093-3611 R&D Projects: GA ČR GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : arc anode * dc arc jet * anode restrike * low pressure Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.136, year: 2005

  9. The Roles of Biofilm Conductivity and Donor Substrate Kinetics in a Mixed-Culture Biofilm Anod

    Science.gov (United States)

    We experimentally assessed kinetics and thermodynamics of electron transfer (ET) from the donor substrate (acetate) to the anode for a mixed-culture biofilm anode. We interpreted the results with a modified biofilm-conduction model consisting of three ET steps: (1) intracellular...

  10. High Biofilm Conductivity Maintained Despite Anode Potential Changes in a Geobacter-Enriched Biofilm

    Science.gov (United States)

    This study systematically assessed intracellular electron transfer (IET) and extracellular electron transfer (EET) kinetics with respect to anode potential (Eanode) in a mixed-culture biofilm anode enriched with Geobacter spp. High biofilm conductivity (0.96–1.24 mScm^-1) was mai...

  11. Bone Cell–materials Interactions and Ni Ion Release of Anodized Equiatomic NiTi Alloy

    Science.gov (United States)

    Bernard, Sheldon A.; Balla, Vamsi Krishna; Davies, Neal M.; Bose, Susmita; Bandyopadhyay, Amit

    2011-01-01

    Laser processed NiTi alloy was anodized for different durations in H2SO4 electrolyte with varying pH to create biocompatible surfaces with low Ni ion release as well as bioactive surfaces to enhance biocompatibility and bone cell-materials interactions. The anodized surfaces were assessed for their in vitro cell-materials interactions using human fetal osteoblast (hFOB) cells for 3, 7 and 11 days, and Ni ion release up to 8 weeks in simulated body fluids. The results were correlated with surface morphologies of anodized surfaces characterized using field-emission scanning electron microscopy (FESEM). The results show that the anodization creates a surface with nano/micro roughness depending on anodization conditions. The hydrophilicity of NiTi surface was found to improve after anodization due to lower contact angles in cell media, which dropped from 32° to NiTi surfaces after anodization. This work indicates that anodization of NiTi alloy has a positive influence on the surface energy and surface morphology, which in turn improve bone cell-materials interactions and reduce Ni ion release in vitro. PMID:21232641

  12. In-situ electrochemical doping of nanoporous anodic aluminum oxide with indigo carmine organic dye

    International Nuclear Information System (INIS)

    Stępniowski, Wojciech J.; Norek, Małgorzata; Budner, Bogusław; Michalska-Domańska, Marta; Nowak-Stępniowska, Agata; Bombalska, Aneta; Kaliszewski, Miron; Mostek, Anna; Thorat, Sanjay; Salerno, Marco; Giersig, Michael; Bojar, Zbigniew

    2016-01-01

    Nanoporous anodic aluminum oxide was formed in sulfuric acid with addition of indigo carmine. During anodizing, the organic dye was incorporated into the porous oxide walls. X-ray photoelectron spectroscopy revealed the presence of nitrogen and sulfur in the anodic aluminum oxide. Two types of incorporated sulfur were found: belonging to the sulfate anions SO 4 2− of the electrolyte and belonging to the C-SO 3 − side groups of the indigo carmine. Raman spectroscopy confirmed the incorporation and showed that the inorganic–organic hybrid material inherited optical properties from the indigo carmine. Typical modes from pyrrolidone rings, unique for indigo carmine in the investigated system (650 and 1585 cm −1 ), were found to be the strongest for the greatest anodizing voltages used. Despite the indigo carmine incorporation, the morphology of the oxide is still nanoporous and its geometry is still tuned by the voltage applied during aluminum anodization. This work presents an inexpensive and facile approach to doping an inorganic oxide material with organic compounds. - Highlights: • Nanoporous anodic alumina was formed in electrolyte with indigo carmine. • XPS confirmed the presence of N and S in anodic alumina. • Raman spectroscopy revealed indigo carmine bands in anodic alumina. • The higher the voltage, the more indigo carmine was incorporated.

  13. In-situ electrochemical doping of nanoporous anodic aluminum oxide with indigo carmine organic dye

    Energy Technology Data Exchange (ETDEWEB)

    Stępniowski, Wojciech J., E-mail: wojciech.stepniowski@wat.edu.pl [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Norek, Małgorzata [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Budner, Bogusław [Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Michalska-Domańska, Marta [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Nowak-Stępniowska, Agata; Bombalska, Aneta; Kaliszewski, Miron [Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Mostek, Anna [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Thorat, Sanjay; Salerno, Marco [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, Genova I-16163 (Italy); Giersig, Michael [Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Bojar, Zbigniew [Department of Advanced Materials and Technology, Faculty of Advanced Technology and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland)

    2016-01-01

    Nanoporous anodic aluminum oxide was formed in sulfuric acid with addition of indigo carmine. During anodizing, the organic dye was incorporated into the porous oxide walls. X-ray photoelectron spectroscopy revealed the presence of nitrogen and sulfur in the anodic aluminum oxide. Two types of incorporated sulfur were found: belonging to the sulfate anions SO{sub 4}{sup 2−} of the electrolyte and belonging to the C-SO{sub 3}{sup −} side groups of the indigo carmine. Raman spectroscopy confirmed the incorporation and showed that the inorganic–organic hybrid material inherited optical properties from the indigo carmine. Typical modes from pyrrolidone rings, unique for indigo carmine in the investigated system (650 and 1585 cm{sup −1}), were found to be the strongest for the greatest anodizing voltages used. Despite the indigo carmine incorporation, the morphology of the oxide is still nanoporous and its geometry is still tuned by the voltage applied during aluminum anodization. This work presents an inexpensive and facile approach to doping an inorganic oxide material with organic compounds. - Highlights: • Nanoporous anodic alumina was formed in electrolyte with indigo carmine. • XPS confirmed the presence of N and S in anodic alumina. • Raman spectroscopy revealed indigo carmine bands in anodic alumina. • The higher the voltage, the more indigo carmine was incorporated.

  14. Atomic Layer Deposition of SnO2 on MXene for Li-Ion Battery Anodes

    KAUST Repository

    Ahmed, Bilal

    2017-02-24

    In this report, we show that oxide battery anodes can be grown on two-dimensional titanium carbide sheets (MXenes) by atomic layer deposition. Using this approach, we have fabricated a composite SnO2/MXene anode for Li-ion battery applications. The SnO2/MXene anode exploits the high Li-ion capacity offered by SnO2, while maintaining the structural and mechanical integrity by the conductive MXene platform. The atomic layer deposition (ALD) conditions used to deposit SnO2 on MXene terminated with oxygen, fluorine, and hydroxyl-groups were found to be critical for preventing MXene degradation during ALD. We demonstrate that SnO2/MXene electrodes exhibit excellent electrochemical performance as Li-ion battery anodes, where conductive MXene sheets act to buffer the volume changes associated with lithiation and delithiation of SnO2. The cyclic performance of the anodes is further improved by depositing a very thin passivation layer of HfO2, in the same ALD reactor, on the SnO2/MXene anode. This is shown by high-resolution transmission electron microscopy to also improve the structural integrity of SnO2 anode during cycling. The HfO2 coated SnO2/MXene electrodes demonstrate a stable specific capacity of 843 mAh/g when used as Li-ion battery anodes.

  15. Effect of nickel content on the anodic dissolution and passivation of ...

    Indian Academy of Sciences (India)

    The effect of systematic increase of Ni on the anodic dissolution and passivation of Zn–Ni alloys in various concentrations of KOH solution (0.1–1 M) was investigated. The anodic dissolution and passivation behaviour for each pure Zn and Ni in the same studied solutions was also investigated, and the obtained data were ...

  16. FIB-SEM investigation of trapped intermetallic particles in anodic oxide films on AA1050 aluminium

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Møller, Per; Dunin-Borkowski, Rafal E.

    2011-01-01

    Purpose - The purpose of this investigation is to understand the structure of trapped intermetallics particles and localized composition changes in the anodized anodic oxide film on AA1050 aluminium substrates. Design/methodology/approach - The morphology and composition of Fe-containing intermet...

  17. Structure transformations in ion implanted anodic alumina films

    International Nuclear Information System (INIS)

    Cherenda, N.N.; Uglov, V.V.; Litvinovich, G.V.; Daniluyk, A.L.

    2002-01-01

    The effect of ion implantation on aluminium oxide has been widely studied. The change of mechanical, electrical, optical and chemical properties were investigated. Most studies were performed on a single crystal (a- or c-oriented) α-Al 2 O 3 though polycrystalline α-Al 2 O 3 or amorphous aluminium oxide films were the subject of the investigation too. Porous anodic alumina films were the object of the investigation of this work. An unique structure, low cost, controllability and ease of production allow it application in developing of microelectronic devices. Earlier it was shown that implantation of metal ions in anodic alumina films decreases its surface resistance to tens of Ωm. The aim of this work was the investigation of anodic alumina films structure changes after implantation. The implantation of Ti and Cu ions was carried out using a MEVVA source with an impulse duration of 1 ms. The applied acceleration voltage was 80 kV, the ions current density - 53 μA/cm 2 , the doses -1·10 17 ions/cm 2 and 1.5·10 18 ions/cm 2 . Implantation was carried out into two types of crystalline structure: amorphous and γ-Al 2 O 3 . The latter structure was produced by annealing at 830 deg. C. A variety of techniques were used for phase and element composition investigations: X-ray diffraction analysis, Auger electron spectroscopy, Rutherford backscattering analysis and scanning electron microscopy. It was found that implantation into amorphous film results in the formation of γ-AO 2 O 3 while implantation into γ-Al 2 O 3 film - in the formation of an amorphous structure. Implantation both to amorphous and crystalline AA films also led to the formation of θ-Al 2 O 3 phase inclusions in the film structure. The whole structure of AA films with the thickness of 200 μm undergoes these transformations. Implantation also lead to sputtering of the surface barrier layer thus resulting in the shift of the ions depth profile to the surface at higher doses. Diffusion of Ti

  18. Corrosion Prevention of Steel Reinforcement in 7.5% NaCl Solution using Pure Magnesium Anode

    Science.gov (United States)

    Iyer Murthy, Yogesh; Gandhi, Sumit; Kumar, Abhishek

    2018-03-01

    The current work investigates the performance of pure Magnesium on corrosion prevention of steel reinforcements by way of sacrificial anoding. Two set of six steel reinforcements were tested for half-cell potential, weight loss, anode efficiency and tensile strength for each of the sacrificial anodes in a high chloride atmosphere of 7.5% NaCl in tap water. Significant reduction in weight of anode was observed during the initial 12 days. The reduction in weight of steel reinforcements tied with anodes was found to be negligible, while that of reinforcements without anodes was significantly higher. Five distinct zones of corrosion were observed during the test. The tensile strength of steel cathodically protected by Mg alloy anodes was found less affected. It could be concluded that pure Mg anode provides an effective way of corrosion mitigation.

  19. Evaluating the impacts of migration in the biofilm anode using the model PCBIOFILM

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, Andrew K., E-mail: andrew_marcus@asu.ed [Center for Environmental Biotechnology, The Biodesign Institute at Arizona State University, P.O. Box 875701, Tempe, AZ 85287-5701 (United States); Torres, Cesar I., E-mail: cit@asu.ed [Center for Environmental Biotechnology, The Biodesign Institute at Arizona State University, P.O. Box 875701, Tempe, AZ 85287-5701 (United States); Rittmann, Bruce E., E-mail: Rittmann@asu.ed [Center for Environmental Biotechnology, The Biodesign Institute at Arizona State University, P.O. Box 875701, Tempe, AZ 85287-5701 (United States)

    2010-09-30

    Microbial electrochemical cells depend on the reaction by anode-respiring bacteria (ARB). The ARB reaction generates multiple e{sup -} and H{sup +}, which take diverging paths, creating a charge imbalance. An electric field must migrate ions to restore electrical neutrality. Here, the model proton condition in bioflim (PCBIOFILM) expands for evaluating the impact of migration on the biofilm anode: the expansion makes the proton condition (PC) work in tandem with the electrical-neutrality condition, which is a novel methodological advancement. The analysis with PCBIOFILM examines relevant scenarios of phosphate- and carbonate-buffered biofilm anodes using established parameters. The analysis demonstrates how: (1) the proton condition (PC) maintains electrical neutrality by achieving charge balance; (2) migration influences the biofilm anode more than non-ARB biofilms; (3) migration increases the overall current density, but by less than 15 percent; and (4) PCBIOFILM without migration accurately captures large-scale trends in biofilm anodes.

  20. Evaluating the impacts of migration in the biofilm anode using the model PCBIOFILM

    International Nuclear Information System (INIS)

    Marcus, Andrew K.; Torres, Cesar I.; Rittmann, Bruce E.

    2010-01-01

    Microbial electrochemical cells depend on the reaction by anode-respiring bacteria (ARB). The ARB reaction generates multiple e - and H + , which take diverging paths, creating a charge imbalance. An electric field must migrate ions to restore electrical neutrality. Here, the model proton condition in bioflim (PCBIOFILM) expands for evaluating the impact of migration on the biofilm anode: the expansion makes the proton condition (PC) work in tandem with the electrical-neutrality condition, which is a novel methodological advancement. The analysis with PCBIOFILM examines relevant scenarios of phosphate- and carbonate-buffered biofilm anodes using established parameters. The analysis demonstrates how: (1) the proton condition (PC) maintains electrical neutrality by achieving charge balance; (2) migration influences the biofilm anode more than non-ARB biofilms; (3) migration increases the overall current density, but by less than 15 percent; and (4) PCBIOFILM without migration accurately captures large-scale trends in biofilm anodes.

  1. Fabrication and assembly of BOLVAPS (boil-off lithium vapor source) ceramic-option half anodes

    Energy Technology Data Exchange (ETDEWEB)

    Moore, R.H.; Appel, D.B.; Cap, J.S.; Spiak, S.H. (Sandia National Labs., Albuquerque, NM (USA)); Cason, B.P.J. (General Electric Co., Largo, FL (USA). Materials and Processes Unit)

    1990-06-01

    In order to generate a lithium vapor on the anode surface within PBFA II, an electrically insulating, lithium-coated substrate is required. One approach for providing this lithium source is the ceramic-option anode. This anode consists of two halves, equatorially split, each containing an insulating ceramic insert onto which a lithium-bearing film is sputtered. A lithium vapor is generated by ohmically pulse heating this film to 1500 K. The half-anode structure required to produce this vapor consists of a ceramic insulator, steel housing, and disk conductors. This report describes the design and fabrication of these separate components and the procedures required to join them to form the half-anode assembly. In addition, appendices are included which contain detailed drawings and specifications for these operations. 5 refs., 10 figs.

  2. Standard test method for laboratory evaluation of magnesium sacrificial anode test specimens for underground applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This test method covers a laboratory procedure that measures the two fundamental performance properties of magnesium sacrificial anode test specimens operating in a saturated calcium sulfate, saturated magnesium hydroxide environment. The two fundamental properties are electrode (oxidation potential) and ampere hours (Ah) obtained per unit mass of specimen consumed. Magnesium anodes installed underground are usually surrounded by a backfill material that typically consists of 75 % gypsum (CaSO4·2H2O), 20 % bentonite clay, and 5 % sodium sulfate (Na2SO4). The calcium sulfate, magnesium hydroxide test electrolyte simulates the long term environment around an anode installed in the gypsum-bentonite-sodium sulfate backfill. 1.2 This test method is intended to be used for quality assurance by anode manufacturers or anode users. However, long term field performance properties may not be identical to property measurements obtained using this laboratory test. Note 1—Refer to Terminology G 15 for terms used ...

  3. Anode-cathode power distribution systems and methods of using the same for electrochemical reduction

    Science.gov (United States)

    Koehl, Eugene R; Barnes, Laurel A; Wiedmeyer, Stanley G; Williamson, Mark A; Willit, James L

    2014-01-28

    Power distribution systems are useable in electrolytic reduction systems and include several cathode and anode assembly electrical contacts that permit flexible modular assembly numbers and placement in standardized connection configurations. Electrical contacts may be arranged at any position where assembly contact is desired. Electrical power may be provided via power cables attached to seating assemblies of the electrical contacts. Cathode and anode assembly electrical contacts may provide electrical power at any desired levels. Pairs of anode and cathode assembly electrical contacts may provide equal and opposite electrical power; different cathode assembly electrical contacts may provide different levels of electrical power to a same or different modular cathode assembly. Electrical systems may be used with an electrolyte container into which the modular cathode and anode assemblies extend and are supported above, with the modular cathode and anode assemblies mechanically and electrically connecting to the respective contacts in power distribution systems.

  4. Features of Porous Anodic Alumina Growth in Galvanostatic Regime in Selenic Acid Based Electrolyte

    International Nuclear Information System (INIS)

    Nazarkina, Y.; Kamnev, K.; Dronov, A.; Dudin, A.; Pavlov, A.; Gavrilov, S.

    2017-01-01

    The features of porous anodic Al 2 O 3 formation process in galvanostatic regime in selenic acid based electrolyte under a range of anodization conditions were investigated. The growth process kinetics of porous anodic Al 2 O 3 was characterized by chronopotentiometric curves. The effect of electrolyte concentration, current density and anodization duration on the oxide porous structure ordering was studied by scanning electron microscopy. Approximate regions of self-ordered porous Al 2 O 3 formation process conditions were estimated. It was found that anodization parameters, at which self-ordered porous structure formation is observed, correspond to the conditions of equilibrium of oxidation and etching rates. It is shown that deviations from these conditions lead to the disordering of the porous structure.

  5. Effects of the Molybdenum Oxide/Metal Anode Interfaces on Inverted Polymer Solar Cells

    International Nuclear Information System (INIS)

    Wu Jiang; Guo Xiao-Yang; Xie Zhi-Yuan

    2012-01-01

    Inverted polymer solar cells with molybdenum oxide (MoO 3 ) as an anode buffer layer and different metals (Al or Ag) as anodes are studied. It is found that the inverted cell with a top Ag anode demonstrates enhanced charge collection and higher power conversion efficiency (PCE) compared to the cell with a top Al anode. An 18% increment of PCE is obtained by replacing Al with Ag as the top anode. Further studies show that an interfacial dipole pointing from MoO 3 to Al is formed at MoO 3 /Al interfaces due to electron transfer from Al to MoO 3 while this phenomenon cannot be observed at MoO 3 /Ag interfaces. It is speculated that the electric field at the MoO 3 /Al interface would hinder hole extraction, and hence reduce the short-circuit current

  6. Effect of Anode Magnetic Shield on Magnetic Field and Ion Beam in Cylindrical Hall Thruster

    International Nuclear Information System (INIS)

    Zhao Jie; Wang Shiqing; Liu Jian; Xu Li; Tang Deli; Geng Shaofei

    2010-01-01

    Numerical simulation of the effect of the anode magnetic shielding on the magnetic field and ion beam in a cylindrical Hall thruster is presented. The results show that after the anode is shielded by the magnetic shield, the magnetic field lines near the anode surface are obviously convex curved, the ratio of the magnetic mirror is enhanced, the width of the positive magnetic field gradient becomes larger than that without the anode magnetic shielding, the radial magnetic field component is enhanced, and the discharge plasma turbulence is reduced as a result of keeping the original saddle field profile and the important role the other two saddle field profiles play in restricting electrons. The results of the particle in cell (PIC) numerical simulation show that both the ion number and the energy of the ion beam increase after the anode is shielded by the magnetic shield. In other words, the specific impulse of the cylindrical Hall thruster is enhanced.

  7. Comparative study of neutron emission from a plasma focus device using two different anode shapes

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, N.; Borthakur, S.; Neog, N. K.; Borthakur, T. K., E-mail: tkborthakur@yahoo.co.uk [Centre of Plasma Physics, Institute for Plasma Research, Sonapur, 782402 Kamrup, Assam (India)

    2016-05-15

    The neutron emission from a low energy (2.2 kJ) plasma focus (PF) device operated with two different shapes (cylindrical and converging) of anodes has been investigated by employing photomultiplier tube and bubble dosimeter. The neutron emission with each anode is analyzed and the results are compared. It is found that the anode shapes strongly influenced the emission of neutron. The X-ray emission is found to be higher in case of converging anode, while neutron emission is found to be higher in case of cylindrical anode. The neutron yield and energy are found to be highly anisotropic in nature which indicates that the beam target mechanism plays a major role in the neutron emission in a PF device. The speed factor as well as the specific heat ratio of pinch column shows a good agreement with the experimentally observed results.

  8. Comparative study of neutron emission from a plasma focus device using two different anode shapes

    Science.gov (United States)

    Talukdar, N.; Borthakur, S.; Neog, N. K.; Borthakur, T. K.

    2016-05-01

    The neutron emission from a low energy (2.2 kJ) plasma focus (PF) device operated with two different shapes (cylindrical and converging) of anodes has been investigated by employing photomultiplier tube and bubble dosimeter. The neutron emission with each anode is analyzed and the results are compared. It is found that the anode shapes strongly influenced the emission of neutron. The X-ray emission is found to be higher in case of converging anode, while neutron emission is found to be higher in case of cylindrical anode. The neutron yield and energy are found to be highly anisotropic in nature which indicates that the beam target mechanism plays a major role in the neutron emission in a PF device. The speed factor as well as the specific heat ratio of pinch column shows a good agreement with the experimentally observed results.

  9. Solid oxide fuel cell power plant with an anode recycle loop turbocharger

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.

    2016-09-27

    An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).

  10. Effect of Nano-Ceria on Physiognomies of Aluminum-5% Zinc Sacrificial Anode

    Directory of Open Access Journals (Sweden)

    Umair Aftab

    2018-04-01

    Full Text Available Sacrificial anodes possessing higher electrochemical efficiency is the demand of marine, oil and gas industries. Due to high energy capability and long life light weight aluminum based anodes are more favorable as compare to magnesium and zinc based anodes to protect the engineering structures from corrosion. In present study an attempt was made to develop Al-5% Zn based composite with nano-ceria. The effect of nano-ceria on physiognomies of Al-5% Zn anode was determined through weight loss, CPR (Corrosion Penetration Rate and emf study in CCP (Close Circuit Potential conditions. The results indicated that by incorporating the ceria in the matrix of Al-5% Zn anode the corrosion inhibition efficiency and hardness were increased significantly.

  11. Anodic Dissolution of Spheroidal Graphite Cast Iron with Different Pearlite Areas in Sulfuric Acid Solutions

    Directory of Open Access Journals (Sweden)

    Yoshikazu Miyata

    2013-01-01

    Full Text Available The rate equation of anodic dissolution reaction of spheroidal graphite cast iron in sulfuric acid solutions at 298 K has been studied. The cast irons have different areas of pearlite. The anodic Tafel slope of 0.043 V decade−1 and the reaction order with respect to the hydroxyl ion activity of 1 are obtained by the linear potential sweep technique. The anodic current density does not depend on the area of pearlite. There is no difference in the anodic dissolution reaction mechanisms between pure iron and spheroidal graphite cast iron. The anodic current density of the cast iron is higher than that of the pure iron.

  12. Solid oxide fuel cell power plant with an anode recycle loop turbocharger

    Science.gov (United States)

    Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.

    2015-07-14

    An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).

  13. Application of silicon zig-zag wall arrays for anodes of Li-ion batteries

    Science.gov (United States)

    Li, G. V.; Rumyantsev, A. M.; Levitskii, V. S.; Beregulin, E. V.; Zhdanov, V. V.; Terukov, E. I.; Astrova, E. V.

    2016-01-01

    Cyclic tests of anodes based on zigzag wall arrays fabricated by the electrochemical etching and post-anodization treatment of silicon have been performed. Compared with anodes based on nanowires and planar thin films, these structures have several advantages. An ex situ analysis of the morphology and structural transformations in a material subjected to cyclic lithiation was conducted by electron microscopy and micro-Raman spectroscopy. The effect of geometrical parameters and a cycling mode on the degradation rate was studied. It is shown that a significant rise in the cycle life of the anode can be obtained by the restriction of the inserted amount of lithium. The anode, subjected to galvanostatic cycling at a rate C/2.8 at a limited charge capacity of 1000 mA · h g-1, demonstrates no degradation after 1200 cycles.

  14. PAT and SEM study of porous silicon formed by anodization methods

    International Nuclear Information System (INIS)

    Liu Jian; Wei Long; Wang Huiyao; Ma Chuangxin; Wang Baoyi

    2000-01-01

    The porous silicon formed by anodization of crystal silicon was studied by positron annihilation technique (PAT) and scanning electron microscopy (SEM). The PAT experiments showed that the mean life and vacancy defects increased with the increasing anodization time. While the intensities of the longest lifetime, several ns-tens ns (ortho-positronium) dropped down. Small single-crystal Si spheres with mean radius of a few μm were observed by SEM after anodization. Pits with mean radius of a few μm from the divorcement of single-crystal spheres were also observed after further anodization. The increases of vacancy defects might be that the extension of structures of porous silicon towards inner layer with anodization time and caused more vacancy defects in inner layer. The SEM observation presented another possibility of the increase of density of vacancy defects in surface layer induced by the change of structures

  15. Magnesium stannide as a high-capacity anode for magnesium-ion batteries

    Science.gov (United States)

    Nguyen, Dan-Thien; Song, Seung-Wan

    2017-11-01

    Driven by the limited global resources of lithium, magnesium metal batteries are considered as potential energy storage systems. The battery chemistry of magnesium metal anode, however, limits the selection of electrolytes, cathode materials and working temperature, making the realization of magnesium metal batteries complicated. Herein, we report the development of a new magnesium-insertion anode, magnesium stannide (Mg2Sn), and demonstrate reversible electrochemical Mg2+-extraction and insertion of Mg2Sn anode at 0.2 V versus Mg, delivering discharge capacity of 270 mAhg-1 in a half-cell with the electrolyte of PhMgCl/THF and enabling of room temperature magnesium-ion batteries with Mg2Sn anode combined with Mg-free oxide cathode and conventional-type electrolyte of Mg(TFSI)2/diglyme. The combination of Mg2Sn anode with various cathodes and electrolytes holds great promise for enabling room temperature magnesium-ion batteries.

  16. Influence of working gas properties on MWPC anode wire modulation effect

    Science.gov (United States)

    Wang, Xiao-Hu; Chen, Xiao-Qiang

    2015-10-01

    For MWPCs used for X-ray position detection, simulation studies of the anode wire modulation effect of the detector were carried out using the Garfield program. Different gas mixtures were used as the working gas in the simulation, so as to obtain the influence of the X-ray cross section and electron diffusion coefficient of the working gases on the anode wire modulation effect of an MWPC with anode wire spacing of 2 mm. Results show that, though a working gas with higher X-ray cross section implies a larger average drift distance for the ionized electrons, such gas mixtures are of little use in improving the anode wire modulation effect of MWPCs. It is found that the transverse electron diffusion coefficient is the determining factor for the extent of the anode wire modulation effect in the detector. Supported by Scientific Research Fund of Sichuan Provincial Education Department (11ZA140)

  17. Structure of anodized Al–Zr sputter deposited coatings and effect on optical appearance

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Canulescu, Stela; Shabadi, Rajashekhara

    2014-01-01

    The mechanism of interaction of light with the microstructure of anodized layer giving specific optical appearance is investigated using Al–Zr sputter deposited coating as a model system on an AA6060 substrate. Differences in the oxidative nature of various microstructural components result...... in the evolution of typical features in the anodized layer, which are investigated as a function of microstructure and correlated with its optical appearance. The Zr concentration in the coating was varied from 6 wt.% to 23 wt.%. Heat treatment of the coated samples was carried out at 550°C for 4 h in order...... to evolve Al–Zr based second phase precipitates in the microstructure. Anodizing was performed using 20 wt.% sulphuric acidat 18°C with an intention to study the effect of anodizing on the Al–Zr based precipitates in the coating.Detailed microstructural characterization of the coating and anodized layer...

  18. Surface characterization and influence of anodizing process on fatigue life of Al 7050 alloy

    International Nuclear Information System (INIS)

    Shahzad, Majid; Chaussumier, Michel; Chieragatti, Remy; Mabru, Catherine; Rezai-Aria, Farhad

    2011-01-01

    Highlights: → We studied the effect of surface treatments on fatigue behaviour of 7050 alloy. → Dissolution of constituent particles in pickling solution result in pits formation. → Decrease is fatigue life caused by anodization is small. → Multi-site cracks initiation has been observed for pickled and anodized specimens. -- Abstract: The present study investigates the influence of anodizing process on fatigue life of aluminium alloy 7050-T7451 by performing axial fatigue tests at stress ratio 'R' of 0.1. Effects of pre-treatments like degreasing and pickling employed prior to anodizing on fatigue life were studied. The post-exposure surface observations were made by scanning electron microscope (SEM) to characterize the effect of each treatment before fatigue testing. The surface observations have revealed that degreasing did not change the surface topography while pickling solution resulted in the formation of pits at the surface. Energy dispersive spectroscopy (EDS) was used to identify those constituent particles which were responsible for the pits formation. These pits are of primary concern with respect to accelerated fatigue crack initiation and subsequent anodic coating formation. The fatigue test results have shown that pickling process was detrimental in reducing the fatigue life significantly while less decrease has been observed for anodized specimens. Analyses of fracture surfaces of pickled specimens have revealed that the process completely changed the crack initiation mechanisms as compared to non-treated specimens and the crack initiation started at the pits. For most of the anodized specimens, fatigue cracks still initiated at the pits with very few cracks initiated from anodic coating. The decrease in fatigue life for pickled and anodized specimens as compared to bare condition has been attributed to decrease in initiation period and multi-site crack initiations. Multi-site crack initiation has resulted in rougher fractured surfaces for

  19. Electrochemical characteristics of bundle-type silicon nanorods as an anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Nguyen, Si Hieu; Lim, Jong Choo; Lee, Joong Kee

    2012-01-01

    Highlights: ► A metal-assisted chemical etching technique was performed on Si thin films. ► The etching process resulted in the formation of bundle-type Si nanorods. ► The morphology of Si electrodes closely relate to electrochemical characteristics. - Abstract: In order to prepare bundle-type silicon nanorods, a silver-assisted chemical etching technique was used to modify a 1.6 μm silicon thin film, which was deposited on Cu foil by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition. The bundle-type silicon nanorods on Cu foil were employed as anodes for a lithium secondary battery, without further treatment. The electrochemical characteristics of the pristine silicon thin film anodes and the bundle-type silicon nanorod anodes are different from one another. The electrochemical performance of the bundle-type silicon nanorod anodes exceeded that of the pristine Si thin film anodes. The specific capacity of the bundle-type silicon nanorod anodes is much higher than 3000 mAh g −1 at the first charge (Li insertion) cycle. The coulombic efficiency of bundle-type silicon anodes was stable at more than 97%, and the charge capacity remained at 1420 mAh g −1 , even after 100 cycles of charging and discharging. The results from the differential voltage analysis showed a side reaction at around 0.44–0.5 V, and the specific potential of this side reaction decreased after each cycle. The apparent diffusion coefficients of the two anode types were in the range of 10 −13 –10 −16 cm 2 s −1 in the first cycle. In subsequent charge cycles, these values for the silicon thin film anodes and the silicon nanorod bundle anode were approximately 10 −12 –10 −14 and 10 −13 –10 −15 cm 2 s −1 , respectively.

  20. Comparative metagenomics of anode-associated microbiomes developed in rice paddy-field microbial fuel cells.

    Directory of Open Access Journals (Sweden)

    Atsushi Kouzuma

    Full Text Available In sediment-type microbial fuel cells (sMFCs operating in rice paddy fields, rice-root exudates are converted to electricity by anode-associated rhizosphere microbes. Previous studies have shown that members of the family Geobacteraceae are enriched on the anodes of rhizosphere sMFCs. To deepen our understanding of rhizosphere microbes involved in electricity generation in sMFCs, here, we conducted comparative analyses of anode-associated microbiomes in three MFC systems: a rice paddy-field sMFC, and acetate- and glucose-fed MFCs in which pieces of graphite felt that had functioned as anodes in rice paddy-field sMFC were used as rhizosphere microbe-bearing anodes. After electric outputs became stable, microbiomes associated with the anodes of these MFC systems were analyzed by pyrotag sequencing of 16S rRNA gene amplicons and Illumina shotgun metagenomics. Pyrotag sequencing showed that Geobacteraceae bacteria were associated with the anodes of all three systems, but the dominant Geobacter species in each MFC were different. Specifically, species closely related to G. metallireducens comprised 90% of the anode Geobacteraceae in the acetate-fed MFC, but were only relatively minor components of the rhizosphere sMFC and glucose-fed MFC, whereas species closely related to G. psychrophilus were abundantly detected. This trend was confirmed by the phylogenetic assignments of predicted genes in shotgun metagenome sequences of the anode microbiomes. Our findings suggest that G. psychrophilus and its related species preferentially grow on the anodes of rhizosphere sMFCs and generate electricity through syntrophic interactions with organisms that excrete electron donors.

  1. An Indium-Free Anode for Large-Area Flexible OLEDs: Defect-Free Transparent Conductive Zinc Tin Oxide

    NARCIS (Netherlands)

    Morales-Masis, M.; Dauzou, F.; Jeangros, Q.; Dabirian, A.; Lifka, H.; Gierth, R.; Ruske, M.; Moet, D.; Hessler-Wyser, A.; Ballif, C.

    2016-01-01

    Flexible large-area organic light-emitting diodes (OLEDs) require highly conductive and transparent anodes for efficient and uniform light emission. Tin-doped indium oxide (ITO) is the standard anode in industry. However, due to the scarcity of indium, alternative anodes that eliminate its use are

  2. OXIDATION OF DRY HYDROCARBONS AT HIGH-POWER DENSITY ANODES

    Energy Technology Data Exchange (ETDEWEB)

    K.Krist; O. Spaldon-Stewart; R. Remick

    2004-03-01

    This work builds upon discoveries by the University of Pennsylvania and others pertaining to the oxidation of dry hydrocarbon fuels in high temperature solid oxide fuel cells. The work reported here was restricted primarily to dry methane and confirms that YSZ-based cells, having ceria in the anode as a catalyst and copper in the anode as a current collector, can operate on dry methane for extended periods. Thirty-three lab-scale cells of various designs were fabricated and operated under a variety of conditions. The longest-lived cell gave stable performance on dry methane at 800 C for over 305 hours. Only slight carbon deposition was noted at the completion of the test. A corresponding nickel/YSZ-based anode would have lasted for less than an hour under these test conditions (which included open circuit potential measurements) before carbon fouling essentially destroyed the cell. The best performing cell achieved 112 mW/cm{sub 2} on dry methane at 800 C. Several problems were encountered with carbon fouling and declining open circuit voltages in many of the test cells after switching from operation on hydrogen to dry methane. Although not rigorously confirmed by experimentation, the results suggested that air infiltration through less than perfect perimeter seals or pinholes in the electrolytes, or both gave rise to conditions that caused the carbon fouling and OCV decline. Small amounts of air reacting with methane in a partial oxidation reaction could produce carbon monoxide that, in turn, would deposit the carbon. If this mechanism is confirmed, it implies that near perfect hardware is required for extended operation. Some evidence was also found for the formation of electrical shorts, probably from carbon deposits bridging the electrolyte. Work with odorized methane and with methane containing 100-ppm hydrogen sulfide confirmed that copper is stable at 800 C in dry hydrocarbon fuels in the presence of sulfur. In a number of cases, but not exclusively, the

  3. Parallel vacuum arc discharge with microhollow array dielectric and anode

    International Nuclear Information System (INIS)

    Feng, Jinghua; Zhou, Lin; Fu, Yuecheng; Zhang, Jianhua; Xu, Rongkun; Chen, Faxin; Li, Linbo; Meng, Shijian

    2014-01-01

    An electrode configuration with microhollow array dielectric and anode was developed to obtain parallel vacuum arc discharge. Compared with the conventional electrodes, more than 10 parallel microhollow discharges were ignited for the new configuration, which increased the discharge area significantly and made the cathode eroded more uniformly. The vacuum discharge channel number could be increased effectively by decreasing the distances between holes or increasing the arc current. Experimental results revealed that plasmas ejected from the adjacent hollow and the relatively high arc voltage were two key factors leading to the parallel discharge. The characteristics of plasmas in the microhollow were investigated as well. The spectral line intensity and electron density of plasmas in microhollow increased obviously with the decease of the microhollow diameter

  4. Analysis of Permalloy films prepared on anodized alumina templates

    Energy Technology Data Exchange (ETDEWEB)

    Getlawi, Saleh; Koblischka, Michael R.; Hartmann, Uwe [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany)

    2010-07-01

    The magnetic properties of Permalloy (Py) systems have been extensively studied for thick films due to the important role in many technological applications, e.g., in magnetoresistive-based sensors and devices. Nanopatterned magnetic media are important for various current approaches in magnetoelectronics and magnetic recording. Commercially available anodized aluminia templates with pore diameters of 100 mm and 30 mm were employed as substrates for Py thin films. The films were prepared by dc-magnetron sputtering. The film thickness was between 7 nm and 30 nm. The obtained antidot patterns were observed by electron and force microscopy. The resulting magnetic domain structures were characterized by means of magnetic force microscopy performed in externally applied magnetic fields. Additionally, the magnetic parameters were characterized by means of SQUID magnetometry.

  5. Measurement of the Photoelectron Detection Efficiency of the HPD Anode

    CERN Document Server

    Carson, L; Soler, P

    2009-01-01

    This paper reports on measurements carried out on the Hybrid Photon Detectors (HPDs) of the LHCb RICH detectors. The purpose of these tests is to determine the photoelectron detection efficiency $\\eta$ of the HPD anode. Knowledge of $\\eta$ is required for an accurate simulation of the RICH detectors. It is found that this efficiency is $(93.3\\pm0.7)\\%$ for a 50 ns digital readout window, and $(87.9\\pm1.4)\\%$ for a 25 ns digital readout window. The 25 ns result exceeds the LHCb-RICH requirement of 85\\%, and is in agreement both with direct $\\eta$ measurements using preseries HPDs, and with indirect measurements from testbeams using preseries and production HPDs.

  6. Fano resonance in anodic aluminum oxide based photonic crystals.

    Science.gov (United States)

    Shang, Guo Liang; Fei, Guang Tao; Zhang, Yao; Yan, Peng; Xu, Shao Hui; Ouyang, Hao Miao; Zhang, Li De

    2014-01-08

    Anodic aluminum oxide based photonic crystals with periodic porous structure have been prepared using voltage compensation method. The as-prepared sample showed an ultra-narrow photonic bandgap. Asymmetric line-shape profiles of the photonic bandgaps have been observed, which is attributed to Fano resonance between the photonic bandgap state of photonic crystal and continuum scattering state of porous structure. And the exhibited Fano resonance shows more clearly when the sample is saturated ethanol gas than air-filled. Further theoretical analysis by transfer matrix method verified these results. These findings provide a better understanding on the nature of photonic bandgaps of photonic crystals made up of porous materials, in which the porous structures not only exist as layers of effective-refractive-index material providing Bragg scattering, but also provide a continuum light scattering state to interact with Bragg scattering state to show an asymmetric line-shape profile.

  7. Barrier and porous anodic oxides on InSb

    Energy Technology Data Exchange (ETDEWEB)

    Suleiman, A.; Hashimoto, T. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: peter.skeldon@manchester.ac.uk; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Echeverria, F. [Dpto de Ing. Metalurgica y de Materiales, Universidad de Antioquia, Oficina 18-240, Calle 67 No. 53-108, A.A. 1226, Medellin (Colombia); Graham, M.J.; Sproule, G.I.; Moisa, S. [Institute for Microstructural Sciences, National Research Council of Canada, Montreal Road, Ottawa, K1A 0R6 (Canada); Habazaki, H. [Graduate Engineering School, Hokkaido University, N13 W8, Kita-ku, Sapporo 060-8628 (Japan); Bailey, P.; Noakes, T.C.Q. [Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom)

    2008-05-15

    Anodizing of InSb at 5 mA cm{sup -2} in sodium tungstate electrolyte is shown to produce barrier-type amorphous oxide at relatively low voltages, to about 40 V, and porous-type amorphous oxide at increased voltages. The barrier-type amorphous oxide, consisting of units of In{sub 2}O{sub 3} and Sb{sub 2}O{sub 3}, distributed relatively uniformly throughout the film, develops at a formation ratio of 2.2 {+-} 0.2 nm V{sup -1}. The outer 15-20% of the film also contains tungsten species. The relatively high efficiency of barrier film growth reduces significantly with transition to porous oxide, which is associated additionally with generation of oxygen at the film surface. The final oxide, at 65 V, comprises pores, of typical diameter 80 nm, orientated approximately normal to the substrate and extending from a barrier region to the film surface.

  8. Application of Anodization Process for Cast Aluminium Surface Properties Enhancement

    Directory of Open Access Journals (Sweden)

    Włodarczyk-Fligier A.

    2016-09-01

    Full Text Available An huge interest is observed in last years in metal matrix composite, mostly light metal based, which have found their applications in many industry branches, among others in the aircraft industry, automotive-, and armaments ones, as well as in electrical engineering and electronics, where one of the most important issue is related to the corrosion resistance, especially on the surface layer of the used aluminium alloys. This elaboration presents the influence of ceramic phase on the corrosion resistance, quality of the surface layer its thickness and structure of an anodic layer formed on aluminium alloys. As test materials it was applied the aluminium alloys Al-Si-Cu and Al-Cu-Mg, for which heat treatment processes and corrosion tests were carried out. It was presented herein grindability test results and metallographic examination, as well. Hardness of the treated alloys with those ones subjected to corrosion process were compared.

  9. Anode reactive bleed and injector shift control strategy

    Science.gov (United States)

    Cai, Jun [Rochester, NY; Chowdhury, Akbar [Pittsford, NY; Lerner, Seth E [Honeoye Falls, NY; Marley, William S [Rush, NY; Savage, David R [Rochester, NY; Leary, James K [Rochester, NY

    2012-01-03

    A system and method for correcting a large fuel cell voltage spread for a split sub-stack fuel cell system. The system includes a hydrogen source that provides hydrogen to each split sub-stack and bleed valves for bleeding the anode side of the sub-stacks. The system also includes a voltage measuring device for measuring the voltage of each cell in the split sub-stacks. The system provides two levels for correcting a large stack voltage spread problem. The first level includes sending fresh hydrogen to the weak sub-stack well before a normal reactive bleed would occur, and the second level includes sending fresh hydrogen to the weak sub-stack and opening the bleed valve of the other sub-stack when the cell voltage spread is close to stack failure.

  10. Electro-catalytic degradation of sulfisoxazole by using graphene anode.

    Science.gov (United States)

    Wang, Yanyan; Liu, Shuan; Li, Ruiping; Huang, Yingping; Chen, Chuncheng

    2016-05-01

    Graphite and graphene electrodes were prepared by using pure graphite as precursor. The electrode materials were characterized by a scanning electron microscope (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV) measurements. The electro-catalytic activity for degradation of sulfisoxazole (SIZ) was investigated by using prepared graphene or graphite anode. The results showed that the degradation of SIZ was much more rapid on the graphene than that on the graphite electrode. Moreover, the graphene electrode exhibited good stability and recyclability. The analysis on the intermediate products and the measurement of active species during the SIZ degradation demonstrated that indirect oxidation is the dominant mechanism, involving the electro-catalytic generation of OH and O2(-) as the main active oxygen species. This study implies that graphene is a promising potential electrode material for long-term application to electro-catalytic degradation of organic pollutants. Copyright © 2015. Published by Elsevier B.V.

  11. Lithium ion batteries with titania/graphene anodes

    Science.gov (United States)

    Liu, Jun; Choi, Daiwon; Yang, Zhenguo; Wang, Donghai; Graff, Gordon L; Nie, Zimin; Viswanathan, Vilayanur V; Zhang, Jason; Xu, Wu; Kim, Jin Yong

    2013-05-28

    Lithium ion batteries having an anode comprising at least one graphene layer in electrical communication with titania to form a nanocomposite material, a cathode comprising a lithium olivine structure, and an electrolyte. The graphene layer has a carbon to oxygen ratio of between 15 to 1 and 500 to 1 and a surface area of between 400 and 2630 m.sup.2/g. The nanocomposite material has a specific capacity at least twice that of a titania material without graphene material at a charge/discharge rate greater than about 10 C. The olivine structure of the cathode of the lithium ion battery of the present invention is LiMPO.sub.4 where M is selected from the group consisting of Fe, Mn, Co, Ni and combinations thereof.

  12. Gas detector with a μm size strips anode

    International Nuclear Information System (INIS)

    Oed, A.

    1988-01-01

    A flat electrode device for an ionizing radiation multidetector, particularly for an X-ray detector used in tomodensitometry, is presented. It consists of either two active electrodes of the same kind, or an anode-electrode and a cathode electrode, on opposite sides of a base plate. The device avoids problems linked to flatness and parallelism, and the base plate consists of at least two intermediate plates separated by a space containing at least layer of binding material. The device thus overcomes difficulties associated with thickness and the need to stop ionizing radiation from passing from one cell to another by traversing the base plate. The steps of the fabrication process are detailed [fr

  13. Ordered Nanomaterials Thin Films via Supported Anodized Alumina Templates

    Directory of Open Access Journals (Sweden)

    Mohammed eES-SOUNI

    2014-10-01

    Full Text Available Supported anodized alumina template films with highly ordered porosity are best suited for fabricating large area ordered nanostructures with tunable dimensions and aspect ratios. In this paper we first discuss important issues for the generation of such templates, including required properties of the Al/Ti/Au/Ti thin film heterostructure on a substrate for high quality templates. We then show examples of anisotropic nanostructure films consisting of noble metals using these templates, discuss briefly their optical properties and their applications to molecular detection using surface enhanced Raman spectroscopy. Finally we briefly address the possibility to make nanocomposite films, exemplary shown on a plasmonic-thermochromic nanocomposite of VO2-capped Au-nanorods.

  14. Photoelectron backscattering from silicon anodes of hybrid photodetector tubes

    CERN Document Server

    D'Ambrosio, C

    2000-01-01

    The impact of photoelectron backscattering on spectral distributions measured with hybrid photodetector tubes has been calculated. The calculations are based on the backscattering coefficient mu , the average number of photoelectrons N/sub phel/ emitted from the photocathode, and on the distribution of the fractional photoelectron energy q absorbed in silicon during the backscattering process. We obtained the following results: the average number of absorbed (measured) photoelectrons N/sub meas/ in the silicon anode amounts to ~88% of the incident N/sub phel/. Photoelectron- and gamma-absorption peaks are broadened by a factor 1.043 due to backscattering. As an example, for photomultiplier tubes, this broadening can amount to an average factor of 1.18 due to statistic and gain fluctuations on the dynode chain. (15 refs).

  15. Mathematical modeling of transport phenomena in porous SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, M.M.; Li, X. [Department of Mechanical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Dincer, I. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (UOIT) Oshawa, Ontario L1H 7K4 (Canada)

    2007-01-15

    In the present study, a mathematical model describing the transport of multi-component species inside porous SOFC anodes is developed. The model considers the reaction zone layer as a distinct volume rather than a mere mathematical surface (boundary condition) as treated in the existing models. The reaction zone layer is a relatively thin layer in the vicinity of electrolyte where electrochemical H{sub 2} oxidation takes place to produce electrons and water vapor. The model also incorporates the effect of Knudsen diffusion in the porous electrode and reaction zone layers. Simulations are performed using multi-component ethanol reformate fuel to predict the distribution of multi-component species in the electrode and reaction zone layers at different loads (current densities). In addition, the effect of shift reaction on the concentration over-potential is examined. Moreover, the effect of treating reaction zone layer as a discrete volume is investigated. (author)

  16. Investigation of anodic oxide coatings on zirconium after heat treatment

    International Nuclear Information System (INIS)

    Sowa, Maciej; Dercz, Grzegorz; Suchanek, Katarzyna; Simka, Wojciech

    2015-01-01

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment

  17. Reactivity descriptors for direct methanol fuel cell anode catalysts

    DEFF Research Database (Denmark)

    Ferrin, Peter; Nilekar, Anand Udaykumar; Greeley, Jeff

    2008-01-01

    We have investigated the anode reaction in direct methanol fuel cells using a database of adsorption free energies for 16 intermediates on 12 close-packed transition metal surfaces calculated with periodic, self-consistent, density functional theory (DFT-GGA). This database, combined with a simple...... electrokinetic model of the methanol electrooxidation reaction, yields mechanistic insights that are consistent with previous experimental and theoretical studies on Pt, and extends these insights to a broad spectrum of other transition metals. In addition, by using linear scaling relations between...... the adsorption free energies of various intermediates in the reaction network, we find that the results determined with the full database of adsorption energies can be estimated by knowing only two key descriptors for each metal surface: the free energies of OH and CO on the surface. Two mechanisms for methanol...

  18. Anodic stripping voltammetry – ASV for determination of heavy metals

    International Nuclear Information System (INIS)

    Barón-Jaimez, J; Joya, M R; Barba-Ortega, J

    2013-01-01

    Although voltammetric methods presented a number of difficulties in its early stages, nowadays ''ASV'' anodic stripping voltammetry is considered one of the most sensitive electro-analytical and suitable for trace-level determination of many metals and compounds in environmental samples, clinical and industrial. Its sensitivity is attributed to the combination of a step of pre-concentration effective together with an electrochemical advanced measurement of accumulated analyte. This paper presents an overview of the voltammetry, which includes a group of electro-analytical methods, in them the information about analyte is obtained from measurements of the current flowing in an electrochemical cell when applied a potential difference to an suitable electrode system

  19. Electrochemical synthesis of magnetic nanostructures using anodic aluminum oxide templates

    Science.gov (United States)

    Gong, Jie

    In this dissertation, template electrodeposition was employed to fabricate high quality magnetic nanostructures suited for the reliable investigation of novel spintronics phenomena such as CIMS, BMR, and CPP-GMR. Several critical aspects/steps relating to the synthesis process were investigated in this work. In order to obtain high quality magnetic nanostructures, free-standing and Si-supported anodic aluminum oxide templates with closely controlled pore diameters, lengths, as well as constriction sizes, were synthesized by anodization, followed by appropriate post-processing. The pore opening size on the barrier layer can be controlled down to 5 nm by ion beam etching. After optimization of the compositional, structural, and magnetic properties of homogeneous FeCoNiCu layers electrodeposited under different conditions, the pulsed deposition process of FeCoNI/Cu multilayers on n-Si was studied. The influence of Cu deposition potential and Fe2+ concentration on microstructure, chemical and electrochemical properties, magnetic properties, and hence magnetotransport properties were assessed. The dissolution of the FM layer during potential transition was minimized in order to control interface sharpness. Combined with the systematic sublayer thickness and FM layer composition optimization, unprecedented GMR sensitivity of 0.11%/Oe at 5-15 Oe was obtained. Growth of multilayer nanowires was performed, and contact to a single wire was attempted using an electrochemical technique. We succeeded in addressing a small number of nanowires and measured a CPP-GMR of 17%. Template electrodeposition thus provides a promising way to repeatably fabricate prototypes for spin dependent transport studies.

  20. Metal carbonates as anode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Shao, Lianyi; Ma, Rui; Wu, Kaiqiang; Shui, Miao; Lao, Mengmeng; Wang, Dongjie; Long, Nengbing; Ren, Yuanlong; Shu, Jie

    2013-01-01

    Highlights: •Metal carbonates are probable anode materials for lithium ion batteries. •CoCO 3 /C composite can deliver an initial discharge capacity of 2096.6 mAh g −1 . •Co, Li 2 CO 3 , Li 2 O, and low-valence carbon are final lithiated products for CoCO 3 . -- Abstract: Six metal carbonates (Li 2 CO 3 , Na 2 CO 3 , SrCO 3 , BaCO 3 , K 2 CO 3 , CoCO 3 ) are tested and compared as anode materials for lithium ion batteries. The electrochemical results show that only CoCO 3 is electrochemically active material and can deliver a high initial capacity of 1425.9 mAh g −1 . The lithium storage mechanism in CoCO 3 is studied by ex situ X-ray diffraction technique, ex situ infrared method, ex situ X-ray photoelectron spectroscopy and in situ X-ray diffraction technique. It is found that the electrochemical reactions between CoCO 3 and Li firstly result in the formation of metal Co and Li 2 CO 3 , and then partial Li 2 CO 3 is further reduced into carbon (C 0 ), low-valence carbon (C 2+ ), and Li 2 O. It also demonstrates that the electrochemical reaction between CoCO 3 and Li is a partially reversible process. Based on these electrochemical results, it is obvious that narrow potential range can acquire a better reversibility for CoCO 3 /Li batteries by suppressing particle pulverization. Besides, the comparison of CoCO 3 , ball-milled CoCO 3 and ball-milled CoCO 3 /C composite also indicates that smaller active particle and carbon buffer are beneficial to obtain better cycling performance and higher reversible capacity

  1. Convergent development of anodic bacterial communities in microbial fuel cells.

    KAUST Repository

    Yates, Matthew D

    2012-05-10

    Microbial fuel cells (MFCs) are often inoculated from a single wastewater source. The extent that the inoculum affects community development or power production is unknown. The stable anodic microbial communities in MFCs were examined using three inocula: a wastewater treatment plant sample known to produce consistent power densities, a second wastewater treatment plant sample, and an anaerobic bog sediment. The bog-inoculated MFCs initially produced higher power densities than the wastewater-inoculated MFCs, but after 20 cycles all MFCs on average converged to similar voltages (470±20 mV) and maximum power densities (590±170 mW m(-2)). The power output from replicate bog-inoculated MFCs was not significantly different, but one wastewater-inoculated MFC (UAJA3 (UAJA, University Area Joint Authority Wastewater Treatment Plant)) produced substantially less power. Denaturing gradient gel electrophoresis profiling showed a stable exoelectrogenic biofilm community in all samples after 11 cycles. After 16 cycles the predominance of Geobacter spp. in anode communities was identified using 16S rRNA gene clone libraries (58±10%), fluorescent in-situ hybridization (FISH) (63±6%) and pyrosequencing (81±4%). While the clone library analysis for the underperforming UAJA3 had a significantly lower percentage of Geobacter spp. sequences (36%), suggesting that a predominance of this microbe was needed for convergent power densities, the lower percentage of this species was not verified by FISH or pyrosequencing analyses. These results show that the predominance of Geobacter spp. in acetate-fed systems was consistent with good MFC performance and independent of the inoculum source.

  2. Anodic and cathodic reactions in molten calcium chloride

    International Nuclear Information System (INIS)

    Fray, D.J.

    2002-01-01

    Calcium chloride is a very interesting electrolyte in that it is available, virtually free, in high purity form as a waste product from the chemical industry. It has a very large solubility for oxide ions, far greater than many alkali halides and other divalent halides and has the same toxicity as sodium chloride and also a very high solubility in water. Intuitively, on the passage of current, it is expected that calcium would be deposited at the cathode and chlorine would evolve at the anode. However, if calcium oxide is added to the melt, it is possible to deposit calcium and evolve oxygen containing gases at the anode, making the process far less polluting than when chlorine is evolved. This process is discussed in terms of the addition of calcium to molten lead. Furthermore, these reactions can be altered dramatically depending upon the electrode materials and the other ions dissolved in the calcium chloride. As calcium is only deposited at very negative cathodic potentials, there are several interesting cathodic reactions that can occur and these include the decomposition of the carbonate ion and the ionization of oxygen, sulphur, selenium and tellurium. For example, if an oxide is used as the cathode in molten calcium chloride, the favoured reaction is shown to be the ionization of oxygen O + 2e - → O 2- rather than Ca 2+ + 2 e- → Ca. The oxygen ions dissolve in the salt leaving the metal behind, and this leads to the interesting hypothesis that metal oxides can be reduced directly to the metal purely by the use of electrons. Examples are given for the reduction of titanium dioxide, zirconium dioxide, chromium oxide and niobium oxide and by mixing oxide powders together and reducing the mixed compact, alloys and intermetallic compounds are formed. Preliminary calculations indicate that this new process should be much cheaper than conventional metallothermic reduction for these elements. (author)

  3. Electrochemical anodizing treatment to enhance localized corrosion resistance of pure titanium.

    Science.gov (United States)

    Prando, Davide; Brenna, Andrea; Bolzoni, Fabio M; Diamanti, Maria V; Pedeferri, Mariapia; Ormellese, Marco

    2017-01-26

    Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.

  4. Effect of anode shape on pinch structure and X-ray emission of plasma focus device

    Science.gov (United States)

    Talukdar, N.; Neog, N. K.; Borthkur, T. K.

    The effect of anode shapes on pinch structure and X-ray emission of plasma focus device operated with cylindrical, diverging, oval and converging anode tips is reported. The pinch structure in the radial compression phase has been investigated by employing a triple pinhole camera. It has been observed that pinch structure as well as the X-ray emission of PF device strongly depends upon anode tip designs. For the first time the studies were carried out in two new shapes of anode tips that is the oval and the divergent one. It has been observed that the oval and diverging anode tips are more conducive for the formation of instabilities and hotspot generation. The studies of X-ray emission were also carried out by employing three channels of a p-i-n diode X-ray spectrometer in entire anode designs to corroborate the results of a triple pinhole camera. Additionally, the effective hard X-ray photon energy was also estimated by the radiography method for all the anode tip designs, which indirectly provide a qualitative idea of the generation of induced accelerating field in the pinched column during compression.

  5. Corrosion Protection of Al/Au/ZnO Anode for Hybrid Cell Application.

    Science.gov (United States)

    Slaughter, Gymama; Stevens, Brian

    2015-11-16

    Effective protection of power sources from corrosion is critical in the development of abiotic fuel cells, biofuel cells, hybrid cells and biobateries for implantable bioelectronics. Corrosion of these bioelectronic devices result in device inability to generate bioelectricity. In this paper Al/Au/ZnO was considered as a possible anodic substrate for the development of a hybrid cell. The protective abilities of corrosive resistant aluminum hydroxide and zinc phosphite composite films formed on the surface of Al/Au/ZnO anode in various electrolyte environments were examined by electrochemical methods. The presence of phosphate buffer and physiological saline (NaCl) buffer allows for the formation of aluminum hyrdroxide and zinc phosphite composite films on the surface of the Al/Au/ZnO anode that prevent further corrosion of the anode. The highly protective films formed on the Al/Au/ZnO anode during energy harvesting in a physiological saline environment resulted in 98.5% corrosion protective efficiency, thereby demonstrating that the formation of aluminum hydroxide and zinc phosphite composite films are effective in the prevention of anode corrosion during energy harvesting. A cell assembly consisting of the Al/Au/ZnO anode and platinum cathode resulted in an open circuit voltage of 1.03 V. A maximum power density of 955.3 mW/ cm² in physiological saline buffer at a cell voltage and current density of 345 mV and 2.89 mA/ cm², respectively.

  6. Three-Dimensional Carbon Nanotube−Textile Anode for High-Performance Microbial Fuel Cells

    KAUST Repository

    Xie, Xing

    2011-01-12

    Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater. © 2011 American Chemical Society.

  7. Surface characteristics of hydroxyapatite films deposited on anodized titanium by an electrochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang [Research Institute, Kuwotech, 970–88, Wolchul-dong, Buk-ku, Gwangju (Korea, Republic of); Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Jeong, Yong-Hoon; Brantley, William A. [Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, The Ohio State, University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials and Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2013-11-01

    The biocompatibility of anodized titanium (Ti) was improved by an electrochemically deposited calcium phosphate (CaP) layer. The CaP layer was grown on the anodized Ti surface in modified simulated body fluid (M-SBF) at 85 °C. The phases and morphologies for the CaP layers were influenced by the electrolyte concentration. Nano flake-like precipitates that formed under low M-SBF concentrations were identified as hydroxyapatite (HAp) crystals orientated in the c-axis direction. In high M-SBF concentrations, the CaP layer formed micro plate-like precipitates on anodized Ti, and micropores were covered with HAp. Proliferation of murine preosteoblast cell (MC3T3-E1) on the HAp/anodized Ti surfaces was significantly higher than for untreated Ti and anodized Ti surfaces. - Highlights: • CaP layers were grown on anodized Ti surfaces by an electrochemical deposition process. • Phases and morphologies of layers were influenced by the electrolyte concentration. • Superior cell proliferation was observed on hydroxyapatite-coated anodized surfaces.

  8. A novel Ni/ceria-based anode for metal-supported solid oxide fuel cells

    Science.gov (United States)

    Rojek-Wöckner, Veronika A.; Opitz, Alexander K.; Brandner, Marco; Mathé, Jörg; Bram, Martin

    2016-10-01

    For optimization of ageing behavior, electrochemical performance, and sulfur tolerance of metal-supported solid oxide fuel cells a new anode concept is introduced, which is based on a Ni/GDC cermet replacing the established Ni/YSZ anodes. In the present work optimized processing parameters compatible with MSC substrates are specified by doing sintering studies on pressed bulk specimen and on real porous anode structures. The electrochemical performance of the Ni/GDC anodes was characterized by means of symmetrical electrolyte supported model-type cells. In this study, three main objectives are pursued. Firstly, the effective technical realization of the Ni/GDC concept is demonstrated. Secondly, the electrochemical behavior of Ni/GDC porous anodes is characterized by impedance spectroscopy and compared with the current standard Ni/YSZ anode. Further, a qualitative comparison of the sulfur poisoning behavior of both anode types is presented. Thirdly, preliminary results of a successful implementation of the Ni/GDC cermet into a metal-supported single cell are presented.

  9. Optimal condition for fabricating superhydrophobic Aluminum surfaces with controlled anodizing processes

    Science.gov (United States)

    Saffari, Hamid; Sohrabi, Beheshteh; Noori, Mohammad Reza; Bahrami, Hamid Reza Talesh

    2018-03-01

    A single step anodizing process is used to produce micro-nano structures on Aluminum (1050) substrates with sulfuric acid as electrolyte. Therefore, surface energy of the anodized layer is reduced using stearic acid modification. Undoubtedly, effects of different parameters including anodizing time, electrical current, and type and concentration of electrolyte on the final contact angle are systemically studied and optimized. Results show that anodizing current of 0.41 A, electrolyte (sulfuric acid) concentration of 15 wt.% and anodizing time of 90 min are optimal conditions which give contact angle as high as 159.2° and sliding angle lower than 5°. Moreover, the study reveals that adding oxalic acid to the sulfuric acid cannot enhance superhydrophobicity of the samples. Also, scanning electron microscopy images of samples show that irregular (bird's nest) structures present on the surface instead of high-ordered honeycomb structures expecting from normal anodizing process. Additionally, X-ray diffraction analysis of the samples shows that only amorphous structures present on the surface. The Brunauer-Emmett-Teller (BET) specific surface area of the anodized layer is 2.55 m2 g-1 in optimal condition. Ultimately, the surface keeps its hydrophobicity in air and deionized water (DIW) after one week and 12 weeks, respectively.

  10. The influence of Ti and Sr alloying elements on electrochemical properties of aluminum sacrificial anodes

    Energy Technology Data Exchange (ETDEWEB)

    Saremi, M.; Sina, H.; Keyvani, A.; Emamy, M. [Metallurgy and Materials Department, University of Tehran, P.O. Box 11365/4563, Tehran (Iran)

    2004-07-01

    Aluminum sacrificial anodes are widely used in cathodic protection of alloys in seawater. The interesting properties due to low specific weight, low electrode potential and high current capacity are often hindered by the presence of a passive oxide film which causes several difficulties in their practical application. In this investigation, the electrochemical behavior of Al- 5Zn-0.02In sacrificial anode is studied in 3 wt. % sodium chloride solution. The experiments focused on the influence of Ti and Sr as alloying elements on electrochemical behavior of aluminum sacrificial anode. Ti and Sr are used in different concentrations from 0.03 to 0.1 wt.% 0.01 to 0.05 wt.%, respectively. NACE efficiency and polarization tests are used in this case. It is shown that by using 0.03 wt.% Ti and 0.01 wt.% Sr as the alloying elements to investigate the anodic behavior of the anodes, homogeneous microstructures are obtained which results in improvement of electrochemical properties of aluminum sacrificial anode such as current capacity and anode efficiency. (authors)

  11. Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell.

    Science.gov (United States)

    Lu, Hui; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2011-10-28

    The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H(2) streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating. This journal is © the Owner Societies 2011

  12. The effect of foil purity on morphology of anodized nanoporous ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wierzbicka, Ewa; Syrek, Karolina [Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30-060 Krakow (Poland); Sulka, Grzegorz D., E-mail: sulka@chemia.uj.edu.pl [Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30-060 Krakow (Poland); Pisarek, Marcin; Janik-Czachor, Maria [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

    2016-12-01

    Highlights: • Anodization of Zr with different purities in an aqueous electrolyte was studied. • The structural parameters of formed anodic oxides were compared. • Effect of Zr foil purity on the hexagonal arrangement of pores and cells in anodic ZrO{sub 2} was investigated. • Current efficiency and rate of anodic oxide formation were estimated. - Abstract: A two-step electrochemical formation of nanoporous zirconium oxide layers on different zirconium foils (purity 99.2% and 99.8%) was investigated. Anodizations were carried out at 20 V in an electrolyte composed of 1 M (NH{sub 4}){sub 2}SO{sub 4} and 0.15 M NH{sub 4}F. It was found that the thickness of grown oxide layer, and consequently, the rate of oxide formation depend slightly on the Zr substrate purity. The pore nucleation and anodization process occur easier in the presence of higher concentration of impurities. From top view SEM images, the structural parameters of oxide layers such as pore diameter, interpore distance, pore density, wall thickness and porosity of anodic oxide layers were estimated for both types of used substrates. On the other hand, cell size, intercell distance and cell density were evaluated from the bottom side of anodic oxide layers. A special emphasis was put on the qualitative analysis of hexagonal arrangement of nanopores and cells. The nanopore and cells arrangements in formed oxides were evaluated using various approaches based on Delaunay triangulations, angular distribution functions (ADFs) and pair distribution functions (PDFs). These results were supported by calculations of percentage of defective pores and cells for both types of used Zr substrates. The use of low purity Zr for anodizing does not affect drastically the morphology of formed nanoporous zirconia and offers a promising perspective to reduce production costs and increase availability of this material.

  13. The effects of microstructure on the corrosion of glycine/nitrate processed cermet inert anodes: A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Jr, C F; Chick, L A; Maupin, G D; Stice, N D

    1991-07-01

    The Inert Electrodes Program at the Pacific Northwest Laboratory (PNL) is supported by the Office of Industrial Processes of the US Department of Energy and is aimed at improving the energy efficiency of Hall-Heroult cells through the development of inert anodes. The inert anodes currently under the study are composed of a cermet material of the general composition NiO-NiFe{sub 2}O{sub 4}-Cu. The program has three primary objectives: (a) to evaluate the anode material in a scaled-up, pilot cell facility, (b) to investigate the mechanisms of the electrochemical reactions at the anodes surface, and (c) to develop sensors for monitoring various anode and/or electrolyte conditions. This report covers the results of a portion of the studies on anode reaction mechanisms. The anode mechanism studies were focused in four areas in FY 1990 and FY 1991: (a) the determination of whether a film formed on cermet inert anodes and (if it existed) the characterization of this film, (b) the determination of the sources of the anode impedance, (c) the evaluation of the effects of silica and a precorroded state on anode corrosion, and (d) a preliminary study on the effect of microstructure on the corrosion properties of the anodes. This report discusses the results of the microstructure studies. 6 refs., 32 figs., 3 tabs.

  14. Note: A simple-structured anode exchangeable X-ray tube.

    Science.gov (United States)

    Nguyen, Thanh-hai; Lee, Chang Jun; Park, Rae-jun; Jin, Gye-Hwan; Kim, Sung Youb; Jeon, Insu

    2013-05-01

    An anode exchangeable X-ray tube of very simple structure was developed. Aluminum, chromium, and copper anode targets were prepared and used to investigate X-ray spectra. X-ray images of a thin wood plate were taken using those targets. The measured energies of the characteristic X-rays of each target agreed well with the presented results. The difference of resolution and brightness of each image was found based on MTF values and intensities. The developed X-ray tube can give high durability, and higher quality X-ray images of an arbitrary object by exchanging anode targets.

  15. The mechanism behind redox instability of anodes in high-temperature SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Chung, Charissa; Larsen, Peter Halvor

    2005-01-01

    Bulk expansion of the anode upon oxidation is considered to be responsible for the lack of redox stability in high-temperature solid oxide fuel cells (SOFCs). The bulk expansion of nickel-yttria stabilized zirconia (YSZ) anode materials was measured by dilatometry as a function of sample geometry......, ceramic component, temperature, and temperature cycling. The strength of the ceramic network and the degree of Ni redistribution appeared to be key parameters of the redox behavior. A model of the redox mechanism in nickel-YSZ anodes was developed based on the dilatometry data and macro...

  16. Pulsed laser deposited Si on multilayer graphene as anode material for lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Gouri Radhakrishnan

    2013-12-01

    Full Text Available Pulsed laser deposition and chemical vapor deposition were used to deposit very thin silicon on multilayer graphene (MLG on a nickel foam substrate for application as an anode material for lithium ion batteries. The as-grown material was directly fabricated into an anode without a binder, and tested in a half-cell configuration. Even under stressful voltage limits that accelerate degradation, the Si-MLG films displayed higher stability than Si-only electrodes. Post-cycling images of the anodes reveal the differences between the two material systems and emphasize the role of the graphene layers in improving adhesion and electrochemical stability of the Si.

  17. Excellent endurance of MWCNT anode in micro-sized Microbial Fuel Cell

    KAUST Repository

    Mink, Justine E.

    2012-08-01

    Microbial Fuel Cells (MFCs) are a sustainable technology for energy production using bioelectrochemical reactions from bacteria. Microfabrication of micro-sized MFCs allows rapid and precise production of devices that can be integrated into Lab-on-a-chip or other ultra low power devices. We show a multi-walled carbon nanotubes (MWCNTs) integrated anode in a biocompatible and high power and current producing device. Long term testing of the MWCNT anode also reveals a high endurance and durable anode material that can be adapted as a long-lasting power source. © 2012 IEEE.

  18. Conical tungsten stamps for the replication of pore arrays in anodic aluminium oxide films

    Science.gov (United States)

    LeClere, D. J.; Thompson, G. E.; Derby, B.

    2009-06-01

    A tungsten master stamp has been generated by applying a novel procedure that includes two-step anodizing, followed by sequential anodizing and pore widening to develop nominally funnelled pores. These conical-shaped pores were filled with tungsten by sputter coating to manufacture a master stamp. Under a pressure of 65 MPa, the master stamp successfully embossed the surface of annealed and electropolished aluminium. The embossed surface was then used to control the position of pores created by anodizing under the conditions used to produce the original pore array.

  19. Scaling up aqueous processing of A-site deficient strontium titanate for SOFC anode supports

    DEFF Research Database (Denmark)

    Verbraeken, Maarten C.; Sudireddy, Bhaskar Reddy; Vasechko, Viacheslav

    2017-01-01

    All ceramic anode supported half cells of technically relevant scale were fabricated in this study, using a novel strontium titanate anode material. The use of this material would be highly advantageous in solid oxide fuel cells due to its redox tolerance and resistance to coking and sulphur......, electrical and mechanical properties of anode supports and half cells will be discussed. The use of two different commercial titanate powders with nominal identical, but in reality different stoichiometries, strongly affect electrical and mechanical properties. Careful consideration of such variations...

  20. Blue luminescence in porous anodic alumina films: the role of the oxalic impurities

    CERN Document Server

    Gao Tao; Zhang Li

    2003-01-01

    Porous anodic alumina (PAA) films with ordered nanopore arrays have been prepared by electrochemically anodizing aluminium in oxalic acid solutions, and the role of the oxalic impurities in the optical properties of PAA films has been discussed. Photoluminescence (PL) measurements show that the PAA films obtained have a blue PL band with a peak position at around 470 nm; the oxalic impurities, incorporated in the PAA films during the anodization processes and already existing in them, could be being transformed into PL centres and hence responsible for this PL emission.

  1. Friction stir processed Al - Metal oxide surface composites: Anodization and optical appearance

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Canulescu, Stela

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate metal oxide (TiO2, Y2O3 and CeO2) particles into the surface of an Aluminium alloy. The surface composites were then anodized in a sulphuric acid electrolyte. The effect of anodizing parameters on the resulting optical...... appearance was studied. Microstructural and morphological characterization was performed using transmission electron microscopy (TEM). The surface appearance was analysed using an integrating sphere-spectrometer setup. Increasing the anodizing voltage changed the surface appearance of the composites from...

  2. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    OpenAIRE

    Zhaoxiang Chen; Xipeng Ren; Limei Ren; Tengchao Wang; Xiaowen Qi; Yulin Yang

    2018-01-01

    Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC) was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC ...

  3. The electrochemical oxidation of H{sub 2} and CO at patterned Ni anodes of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Utz, Annika

    2011-07-01

    In this work, a deeper understanding of the electrochemical oxidation at SOFC anodes was gained by the experimental characterization of patterned Ni anodes in H{sub 2}-H{sub 2}O and CO-CO{sub 2} atmosphere. By high resolution data analysis, the Line Specific Resistance attributed to charge transfer and its dependencies on gas composition, temperature and polarization voltage were identified. Furthermore, the comparison of the performance of patterned and cermet anodes was enabled using a transmission line model. (orig.)

  4. Crack Detection Method Applied to 3D Computed Tomography Images of Baked Carbon Anodes

    Directory of Open Access Journals (Sweden)

    Donald Picard

    2016-11-01

    Full Text Available Carbon anodes used in the aluminium industry were imaged through destructive and non-destructive testing (NDT methods. For the latter case, computed tomography (CT, which has previously been used to map the 3D apparent density distribution, was extended to crack detection. Previous work has shown how to overcome technical hurdles related to crack detection by using percolation-based algorithms operating on low-resolution images of full-scale baked carbon anodes. The previous application to 2D images was extended here to the 3D case. The crack detection algorithm has been performed on anode slices containing several independent macro cracks with different morphologies.

  5. Gallium phosphide as a new material for anodically bonded atomic sensors

    Directory of Open Access Journals (Sweden)

    Nezih Dural

    2014-08-01

    Full Text Available Miniaturized atomic sensors are often fabricated using anodic bonding of silicon and borosilicate glass. Here we describe a technique for fabricating anodically bonded alkali-metal cells using GaP and Pyrex. GaP is a non-birefringent semiconductor that is transparent at alkali-metal resonance wavelengths, allowing new sensor geometries. GaP also has a higher thermal conductivity and lower He permeability than borosilicate glass and can be anodically bonded below 200 °C, which can also be advantageous in other vacuum sealing applications.

  6. Recovery Of Valuable Metals In Tin-Based Anodic Slimes By Carbothermic Reaction

    OpenAIRE

    Han Chulwoong; Kim Young-Min; Son Seong Ho; Choi Hanshin; Kim Tae Bum; Kim Yong Hwan

    2015-01-01

    This study investigated the recovery of anodic slimes by carbothermic reaction in the temperature range of 973~1,273K and amount of carbon as a function of time. Tin anodic slime samples were collected from the bottom of the electrolytic cells during the electro-refining of tin. The anodic slimes are consisted of high concentrated tin, silver, copper and lead oxides. The kinetics of reduction were determined by means of the weight-loss measurement technique. In order to understand in detail o...

  7. Effects of Li4Ti5O12 Anode Electrode Thickness on the Cell Balancing of Hybrid Super Capacitor.

    Science.gov (United States)

    Lee, Jong-Kyu; Yoon, Jung-Rag

    2015-03-01

    The hybrid super capacitor was prepared by controlling the anode electrode thickness to optimize cell balancing. With an increasing anode electrode thickness, the internal resistance increased, while the capacitance was not changed remarkably. The potential of the cathode increased and that of the anode was decreased with the working voltage. However, the potential variation of the cathode was larger than that of the anode due to the difference in the reaction mechanism of the cathode and anode. The discharge capacity retention as a function of the current rates increased and the cycle performance was improved with an increasing anode electrode thickness. The effects of the anode electrode thickness on the electrode potential are also discussed.

  8. Electrochemical polymerization of phenol on 304 stainless steel anodes and subsequent coating structure analysis

    International Nuclear Information System (INIS)

    Bao Liyin; Xiong Rongchun; Wei Gang

    2010-01-01

    Anodic oxidation was carried out using 304 stainless steel anodes in neutral 0.1 mol/L phenol solution with an electrolyte composed of 0.1 mol/L sodium sulfate. This oxidation generated a yellow brown polyphenol coating on the steel anode surface. The reaction conditions discussed in this report relate to the methods of linear scanning, cyclic voltammetry and constant current oxidation. The proper anodic electrode potential for polyphenol deposition was observed to be 1.45 V, with a bath voltage of 2.5 V. The chemical structure of the polyphenol coating was analyzed by infrared spectroscopy and the molecular weight of the soluble part of the coating was detected by gel permeation chromatography. A scanning electron microscope was used to analyze the microstructure of the polyphenol coating, taking advantage of the partial solubility of the polyphenol in tetrahydrofuran. The observed linear and flake-layer modes of the polyphenol coating growth are summarized herein.

  9. Performance of lithium alloy/lithium and calcium/lithium anodes in thionyl chloride cells

    Energy Technology Data Exchange (ETDEWEB)

    Keister, P.; Greenwood, J.M.; Holmes, C.F.; Mead, R.T.

    1985-08-01

    A laminar composite anode construction comprising an inner metal completely surrounded by Li foil was studied as a means of obtaining an end-of-life indicator in a thionyl chloride cell. Inner metals of Ca, 14-2.9 at.% Ca in Li alloys, and 6.7-2.1 at.% Mg in Li alloys were evaluated. Discharge characteristics of cells using these sandwich anodes as well as cells containing the inner anode material alone were determined. It was concluded that cells made with inner anode materials of Ca and Ca/Li alloys containing more than 7 at.% Ca showed promise as a means of obtaining a reliable end-of-life indication. (orig.).

  10. Effect of anode material on the breakdown in low-pressure helium gas

    Science.gov (United States)

    Adams, S. F.; Demidov, V. I.; Kudryavtsev, A. A.; Kurlyandskaya, I. P.; Miles, J. A.; Tolson, B. A.

    2017-11-01

    An experimental study of the electric breakdown in helium gas for the plane-parallel electrode configuration has been conducted using a copper cathode and a variety of anode materials: copper, aluminum, stainless steel, graphite, platinum-plated aluminum and goldplated aluminum. According to the Paschen law for studied electrode configuration, the breakdown voltage is a function of the product of gas pressure and inter-electrode gap. The breakdown processes on the left, lower pressure side of the Paschen curve have been the subject of this investigation. For those pressures, the Paschen curve may become multi-valued, where any given pressure corresponds to three breakdown voltage values. It was experimentally demonstrated that the form of the Paschen curve might strongly depend on the material of the anode and the cleanness of the anode surface. A possible explanation for this phenomenon is that electrons streaming from the cathode are reflected by the surface of the anode.

  11. Evaluation of multi-brush anode systems in microbial fuel cells

    KAUST Repository

    Lanas, Vanessa

    2013-11-01

    The packing density of anodes in microbial fuel cells (MFCs) was examined here using four different graphite fiber brush anode configurations. The impact of anodes on performance was studied in terms of carbon fiber length (brush diameter), the number of brushes connected in parallel, and the wire current collector gage. MFCs with different numbers of brushes (one, three or six) set perpendicular to the cathode all produced similar power densities (1200±40mW/m2) and coulombic efficiencies (60%±5%). Reducing the number of brushes by either disconnecting or removing them reduced power, demonstrating the importance of anode projected area covering the cathode, and therefore the need to match electrode projected areas to maintain high performance. Multi-brush reactors had the same COD removal as single-brush systems (90%). The use of smaller Ti wire gages did not affect power generation, which will enable the use of less metal, reducing material costs. © 2013 Elsevier Ltd.

  12. The simulation of the temperature effects on the microhardness of anodic alumina oxide layers

    Directory of Open Access Journals (Sweden)

    M. Gombár

    2014-01-01

    Full Text Available In order to improve the mechanical properties of the layer deposited by anodic oxidation of aluminum on the material EN AW-1050 H24, in the contribution was investigated the microhardness of the deposited layer as a function of the physic-chemical factors affecting in the process of anodic oxidation at the constant anodic current density J = 3 A.dm-2 in electrolyte formed by sulfuric acid and oxalic acid, with the emphasis on the influence of electrolyte temperature in the range – 1,78 °C to 45,78 °C. The model of the studied dependence was compiled based on mathematical and statistical analysis of matrix from experimental obtained data from composite rotation plan of experiment with five independent variable factors (amount of sulfuric acid in the electrolyte, the amount of oxalic acid in the electrolyte, electrolyte, anodizing time and applied voltage.

  13. Multiple-photon disambiguation on stripline-anode Micro-Channel Plates

    International Nuclear Information System (INIS)

    Jocher, Glenn R.; Wetstein, Matthew J.; Adams, Bernhard; Nishimura, Kurtis; Usman, Shawn M.

    2016-01-01

    Large-Area Picosecond Photo-Detectors (LAPPDs) show great potential for expanding the performance envelope of Micro-Channel Plates (MCPs) to areas of up to 20×20 cm and larger. Such scaling introduces new challenges, including how to meet the electronics readout burden of ever larger area MCPs. One solution is to replace the traditional grid anode used for readout with a microwave stripline anode, thus allowing the channel count to scale with MCP width rather than area. However, stripline anodes introduce new issues not commonly dealt with in grid-anodes, especially as their length increases. One of these issues is the near simultaneous arrival of multiple photons on the detector, creating possible confusion about how to reconstruct their arrival times and positions. We propose a maximum a posteriori solution to the problem and verify its performance in simulated scintillator and water-Cherenkov detectors.

  14. PIC simulation of the anode plasma in a high-power hollow cathode diode

    Science.gov (United States)

    Liu, Laqun; Zou, Wenkang; Wang, Huihui; Guo, Fan; Liu, Dagang

    2018-02-01

    In this paper, the evolution and dynamics of anode plasmas in high-power hollow cathode diodes were studied by particle-in-cell (PIC) simulation. The simulation results show that the ion flow emitted by the anode plasma layer and the increase of the electron current caused by the ion flow will cause a significant decline in the diode impedance in a short time. In addition, the expansion of the anode plasma layer will cause the diode impedance to decrease. The PIC simulation technique is also applied to a high-power hollow cathode diode of a 1.0 MV-LTD generator for anode plasmas, and the PIC simulation results were compared with the experimental data.

  15. Advanced electrolyte/additive for lithium-ion batteries with silicon anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuo; He, Meinan; Su, Chi-Cheung; Zhang, Zhengcheng

    2016-08-01

    State-of-the-art lithium-ion batteries (LIBs) are based on a lithium transition metal oxide cathode, a graphite anode and a nonaqueous carbonate electrolyte. To further increase the energy and power density of LIBs, silicon anodes have been intensively explored due to their high theoretical capacity, low operation potential, and low cost. However, the main challenges for Si anode are the large volume change during lithiation/delithiation process and the instability of the solid-electrolyte-interphase associated with this process. Recently, significant progress has been achieved via advanced material fabrication technologies and rational electrolyte design in terms of improving the Coulombic efficiency and capacity retention. In this paper, new developments in advanced electrolyte and additive for LIBs with Si anode were systematically reviewed, and perspectives over future research were suggested.

  16. The corrosion protection of 6061-T6 aluminum by a polyurethane-sealed anodized coat

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    The corrosion protection of 6061-T6 anodized aluminum afforded by a newly patented polyurethane seal was studied using the ac impedance technique. Values of the average corrosion rates over a 27-day exposure period in 3.5 percent NaCl solutions at pH 5.2 and pH 9.5 compared very favorably for Lockheed-prepared polyurethane-sealed and dichromate-sealed coats of the same thickness. Average corrosion rates for both specimens over the first 7 days of exposure compared well with those for a hard anodized, dichromate-sealed coat, but rose well above those for the hard anodized coat over the entire 27-day period. This is attributed both to the greater thickness of the hard anodized coat, and possibly to its inherently better corrosion protective capability.

  17. Electrochemical polymerization of phenol on 304 stainless steel anodes and subsequent coating structure analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bao Liyin [College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Xiong Rongchun, E-mail: rongchunxiong@163.co [College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wei Gang [College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2010-04-30

    Anodic oxidation was carried out using 304 stainless steel anodes in neutral 0.1 mol/L phenol solution with an electrolyte composed of 0.1 mol/L sodium sulfate. This oxidation generated a yellow brown polyphenol coating on the steel anode surface. The reaction conditions discussed in this report relate to the methods of linear scanning, cyclic voltammetry and constant current oxidation. The proper anodic electrode potential for polyphenol deposition was observed to be 1.45 V, with a bath voltage of 2.5 V. The chemical structure of the polyphenol coating was analyzed by infrared spectroscopy and the molecular weight of the soluble part of the coating was detected by gel permeation chromatography. A scanning electron microscope was used to analyze the microstructure of the polyphenol coating, taking advantage of the partial solubility of the polyphenol in tetrahydrofuran. The observed linear and flake-layer modes of the polyphenol coating growth are summarized herein.

  18. Anode-originated SEI migration contributes to formation of cathode-electrolyte interphase layer

    Science.gov (United States)

    Fang, Shuyu; Jackson, David; Dreibelbis, Mark L.; Kuech, Thomas F.; Hamers, Robert J.

    2018-01-01

    Cathode-electrolyte interphase (CEI) formation is a key process that impacts the performance of lithium-ion batteries. In this work, we characterized the composition and stoichiometry of CEI layer on LiNixMnyCo1-x-yO2 (NMC) cathodes via a novel combination of quantitative correlation analysis of X-ray photoelectron spectra and binder-free cathode formulation. By comparing the CEI formation in NMC-based cells with lithium, graphite and lithium titanate anodes, we demonstrate a CEI formation pathway via migration of surface species that originally formed on the anode side. A case study of cathodes coated by atomic layer deposition with a thin layer of Al2O3 demonstrates that anode-to-cathode migration can be mitigated by ALD cathode coatings. This work highlights the importance of anode-mediated processes in order to correctly interpret surface phenomena on the cathode side and to guide further development of surface protection strategies.

  19. Influence of silicon species on the electric properties of anodic niobia

    International Nuclear Information System (INIS)

    Habazaki, H.; Matsuo, T.; Konno, H.; Shimizu, K.; Nagata, S.; Matsumoto, K.; Takayama, K.; Oda, Y.; Skeldon, P.; Thompson, G.E.

    2003-01-01

    The influence of incorporation of silicon species on the electric properties of anodic niobia, formed in 0.1 mol dm -3 ammonium pentaborate electrolyte, has been examined using sputter-deposited Nb-Si alloys containing 5 and 17 at.% silicon. The potential dependence of the capacitance of anodic niobia, originating from its n-type semiconducting properties, becomes less significant by incorporation of silicon species. In addition, the leakage current decreases with increasing silicon content in the alloy. The thermal stability of the anodic niobia is also enhanced by silicon species; the capacitance and leakage current, which increase significantly for niobium, are little influenced by annealing up to 523 K. The silicon species are incorporated in the inner 72% of the film thickness, as a consequence of immobility of the species in growing anodic niobia. The immobility of silicon species is associated with a strong Si 4+ -O bond, which may also contribute to the reduction of leakage current

  20. Nanoshell Encapsulated Li-ion Battery Anodes for Long Cycle Life, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity rechargeable Li battery anode based on Li metal alloys protected by carbon nanoshells will be developed. A reversible Li-ion capacity exceeding...

  1. The kinetics of anodic dissolution of rhenium in aqueous electrolyte solutions

    International Nuclear Information System (INIS)

    Atanasyants, A.G.; Kornienko, V.A.

    1986-01-01

    The kinetics of anodic rhenium dissolution was investigated by means of potentiodynamic and potentiostatic polarization curves recorded at temperature from 293 to 333 K in different media (NaOH, KOH, NaCl, NaBr, HCl, H 2 SO 4 ) using the rotating disc technique. It is shown that the kinetics of anodic rhenium dissolution and effective activation energy depend not only on the composition and pH value of the solutions but also on the structure of the dissolving rhenium surface. The investigation of the anodic behaviour of the rhenium monocrystal revealed the existence of anisotropy of the monocrystal electrochemical properties. The experimental results point to an important role of adsorption processes in anodic rhenium dissolution. Rhenium dissolution proceeds with formation of intermediate surface adsorption complexes between the metal and the components of the solution

  2. Effect of nano-segregation phases on electrochemical property of high active Al alloy anode

    International Nuclear Information System (INIS)

    Liang, S Q; Zhang, Y; Mao, Z W; Tang, Y; Guan, D K

    2009-01-01

    The effect of nano-segregation phases formed during rolling process on the electrochemical property of Al-Mg-Sn-Bi-Ga-In alloy anode in alkaline solution (80 deg. C, Na 2 SnO 3 + 5mol/L NaOH)was analyzed according to the chronopotentiometry (E-T curves), hydrogen collection tests and modern microstructure analysis. The results show that when controlling the rolling temperature and pass deformation at 370 deg. C and 40% respectively, the Al alloy anode undergoes the dynamic recrystallization, which benefits to the uniform distribution of nano-segregation phases and improvement of electrochemical property of Al alloy anode. The optimum Al alloy anode has the more negative electrode potential of about -1.48V (vs.Hg/HgO) and the lower hydrogen evolution rate of 0.1889mL/ (min·cm 2 ).

  3. Anodic ammonia oxidation to nitrogen gas catalyzed by mixed biofilms in bioelectrochemical systems

    International Nuclear Information System (INIS)

    Zhan, Guoqiang; Zhang, Lixia; Tao, Yong; Wang, Yujian; Zhu, Xiaoyu; Li, Daping

    2014-01-01

    In this paper we report ammonia oxidation to nitrogen gas using microbes as biocatalyst on the anode, with polarized electrode (+600 mV vs. Ag/AgCl) as electron acceptor. In batch experiments, the maximal rate of ammonia-N oxidation by the mixed culture was ∼ 60 mg L −1 d −1 , and nitrogen gas was the main products in anode compartment. Cyclic voltammetry for testing the electroactivity of the anodic biofilms revealed that an oxidation peak appeared at +600 mV (vs. Ag/AgCl), whereas the electrode without biofilms didn’t appear oxidation peak, indicating that the bioanode had good electroactivities for ammonia oxidation. Microbial community analysis of 16S rRNA genes based on high throughput sequencing indicated that the combination of the dominant genera of Nitrosomonas, Comamonas and Paracocus could be important for the electron transfer from ammonia oxidation to anode

  4. Sulfur Poisoning of Ni/stabilized-zirconia Anodes – Effect on Long-Term Durability

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan

    2013-01-01

    -term galvanostatic operation in internal reforming gas mixture (CH4/H2O/H2:30/60/10), with 2 ppm H2S exposure to the anode, at different current densities. The aim was not only to investigate the well-known initial performance drop associated with adsorbed sulfur in the Ni/stabilized-zirconia anodes, but also......Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long...

  5. Use of nuclear reactions to trace the source of oxygen in anodization

    International Nuclear Information System (INIS)

    Lewis, M.B.; Perkins, R.A.

    1978-01-01

    In cases where the anodization of metals involves the use of chemical solutions, the oxidation mechanism is frequently uncertain. In such cases it is usually possible to make oxygen bearing solutes from oxgen which is enriched in isotope-18. After use in anodization, the oxide films can be analyzed by the method of nuclear microanalysis which separately profiles the 18 O and 16 O. In this way the depth distribution of the 18 O can be compared quantitatively with that of the 16 O arising from all other oxygen bearing chemicals in solution. This method was applied to the case of the anodization of vanadium and zirconium. The results indicate an unconventional anodization mechanism for the vanadium case

  6. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.

    2013-10-06

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  7. Enhancing hybrid direct carbon fuel cell anode performance using Ag2O

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    A hybrid-direct carbon fuel cell (HDCFC), consisting of a molten slurry of solid carbon black and (Li-K)2CO3 added to the anode chamber of a solid oxide fuel cell, was characterized using current-potential-power density curves, electrochemical impedance spectroscopy, and cyclic voltammetry. Two...... types of experimental setups were employed in this study, an anode-supported full cell configuration (two electrodes, two atmospheres setup) and a 3-electrode electrolyte-supported half-cell setup (single atmosphere). Anode processes with and without catalysts were investigated as a function...... of temperature (700-800 °C) and anode sweep gas (N2, 4-100% CO2 in N2-CO2). It was shown that the addition of silver based catalysts (Ag, Ag2O, Ag2CO3) into the carbon-carbonate slurry enhanced the performance of the HDCFC....

  8. Effects of Anodic Buffer Layer in Top-Illuminated Organic Solar Cell with Silver Electrodes

    Directory of Open Access Journals (Sweden)

    Tien-Lung Chiu

    2013-01-01

    Full Text Available An efficient ITO-free top-illuminated organic photovoltaic (TOPV based on small molecular planar heterojunction was achieved by spinning a buffer layer of poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS, on the Ag-AgOx anode. The PEDOT:PSS thin film separates the active layer far from the Ag anode to prevent metal quenching and redistributes the strong internal optical field toward dissociated interface. The thickness and morphology of this anodic buffer layer are the key factors in determining device performances. The uniform buffer layer contributes a large short-circuit current and open-circuit voltage, benefiting the final power conversion efficiency (PCE. The TOPV device with an optimal PEDOT:PSS thickness of about 30 nm on Ag-AgOx anode exhibits the maximum PCE of 1.49%. It appreciates a 1.37-fold enhancement in PCE over that of TOPV device without buffer layer.

  9. Modelling of structure and properties of soft carbons with application to carbon anode baking

    Energy Technology Data Exchange (ETDEWEB)

    Gundersen, Oeyvind

    1998-11-01

    This work deals with topics related to modelling and control of ring furnaces for the baking of carbon anodes used in aluminium electrolysis. Anodes made of a granular coke and coal tar pitch are used in aluminium electrolysis. The anode properties are imperative for successful operation of the aluminium smelters. After mixing and forming the anode paste, heat treatment of the carbon blocks takes place in so-called ring furnaces. A ring furnace consists of a series of heat treatment sections where each section is loaded with a batch of anodes. The heat treatment of the anodes in a section consumes a lot of energy, and the anode properties partly depend on the heat treatment program. Previous work in the field of ring furnace modelling, operation and control is shortly reviewed. Both petroleum coke and coal tar pitch belong to the group of soft carbons. Models for structural parameters and porosity of soft carbons are developed. Furthermore, a new model for pyrolysis of coal tar pitch is proposed. Based on the models for pyrolysis, structure and porosity, new models for properties of single phase carbons and composite anodes are developed. These models are suitable for use in optimization of the baking process. A detailed mathematical model of a part of the heat treatment process is formulated in three spatial dimensions. The model is based on first principle descriptions of fundamental physical and chemical phenomena and the resulting model appears as a set of partial differential equations. The spatial differential operators are discretized by using the finite volume approach. In this way, a high dimensional nonlinear state space model is obtained. The model has been simulated using the method of lines. A vector of quantities which describes the anode properties is defined. This property vector constitutes a systematic definition of anode quality where the quality parameters are calculated as nonlinear transformations of the state space vector. Models are derived

  10. Surface Modification of Titanium Using Anodization to Enhance Antimicrobial Properties and Osseointegration

    Science.gov (United States)

    Jain, Sakshi

    Titanium and its alloys are frequently used in dental and orthopedic implants because they have good mechanical strength, chemical stability and biocompatibility. These properties can be further improved by surface treatments such as anodization that are able to grow thicker and produce crystalline oxide layers with controlled morphological and physico-chemical properties. Both anatase (A) and rutile (R) crystalline phases of titanium oxide have been shown to promote bioactivity and antimicrobial effects. In a previous study in our laboratories, four electrolyte mixtures were optimized to produce anodized layers on commercially pure titanium consisting of specific anatase and rutile oxide ratios at an endpoint forming voltage of 180 V. In the present study, changes that occurred in the anodized layers with increasing forming voltage including crystallinity, thickness, surface morphology, surface roughness, surface chemistry, fractal dimension, shear strength, and corrosion resistance were determined for each of these electrolytes. The results showed the crystallinity, thickness, surface pore sizes, and surface roughness increased with increasing forming voltage. Incorporation of phosphorus into the anodized layers was shown in phosphoric acid containing electrolytes at higher forming voltages. Decreases in corrosion resistance were also shown at higher forming voltages in each electrolyte due to increased pore interconnectivity within the anodized layers. In addition, the apatite inducing ability of anodized layers in SBF was examined for selected forming voltages in each electrolyte. Anodization in phosphoric acid containing electrolytes was shown to be more favorable for apatite formation. The streptococcal and MRSA bacterial attachment before and after UV treatments was determined for selected forming voltages in each electrolyte. Additionally, the killing efficacy after 10-minute pre-irradiation with UVA or UVC treatments was determined. UVA treatments showed

  11. A Practical Anodic and Cathodic Curve Intersection Model to Understand Multiple Corrosion Potentials of Fe-Based Glassy Alloys in OH- Contained Solutions.

    Science.gov (United States)

    Li, Y J; Wang, Y G; An, B; Xu, H; Liu, Y; Zhang, L C; Ma, H Y; Wang, W M

    2016-01-01

    A practical anodic and cathodic curve intersection model, which consisted of an apparent anodic curve and an imaginary cathodic line, was proposed to explain multiple corrosion potentials occurred in potentiodynamic polarization curves of Fe-based glassy alloys in alkaline solution. The apparent anodic curve was selected from the measured anodic curves. The imaginary cathodic line was obtained by linearly fitting the differences of anodic curves and can be moved evenly or rotated to predict the number and value of corrosion potentials.

  12. Anode and cathode joints and gap closure in a high current MITL

    International Nuclear Information System (INIS)

    Spielman, R.B.; Hsing, W.W.

    1985-01-01

    Proto II successfully delivers up to 5 MA to an imploding plasma load through an MITL with gaps as small as 3.0 mm. The anode and the cathode have joints which, under some conditions, may cause gap closure. The authors postulate that the gap closure occurs due to acceleration of negative ions from the cathode joint to the anode. Inserting conducting material into the cathode joint eliminated MITL gap closure

  13. Enhanced osteoblast adhesion to drug-coated anodized nanotubular titanium surfaces

    Directory of Open Access Journals (Sweden)

    George E Aninwene II

    2008-06-01

    Full Text Available George E Aninwene II1, Chang Yao2, Thomas J Webster21Department of Biochemical Engineering, University of Maryland, Baltimore, MD; 2Division of Engineering, Brown University, Providence, RI, USAAbstract: Current orthopedic implants have functional lifetimes of only 10–15 years due to a variety of reasons including infection, extensive inflammation, and overall poor osseointegration (or a lack of prolonged bonding of the implant to juxtaposed bone. To improve properties of titanium for orthopedic applications, this study anodized and subsequently coated titanium with drugs known to reduce infection (penicillin/streptomycin and inflammation (dexamethasone using simple physical adsorption and the deposition of such drugs from simulated body fluid (SBF. Results showed improved drug elution from anodized nanotubular titanium when drugs were coated in the presence of SBF for up to 3 days. For the first time, results also showed that the simple physical adsorption of both penicillin/streptomycin and dexamethasone on anodized nanotubular titanium improved osteoblast numbers after 2 days of culture compared to uncoated unanodized titanium. In addition, results showed that depositing such drugs in SBF on anodized titanium was a more efficient method to promote osteoblast numbers compared to physical adsorption for up to 2 days of culture. In addition, osteoblast numbers increased on anodized titanium coated with drugs in SBF for up to 2 days of culture compared to unanodized titanium. In summary, compared to unanodized titanium, this preliminary study provided unexpected evidence of greater osteoblast numbers on anodized titanium coated with either penicillin/streptomycin or dexamethasone using simple physical adsorption or when coated with SBF; results which suggest the need for further research on anodized titanium orthopedic implants possessing drug-eluting nanotubes.Keywords: anodization, titanium, adhesion, simulated body fluid, nanotubes

  14. Biocatalytic anode for glucose oxidation utilizing carbon nanotubes for direct electron transfer with glucose oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Vaze, Abhay; Hussain, Nighat; Tang, Chi [Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060 (United States); Leech, Donal [School of Chemistry, National University of Ireland, Galway (Ireland); Rusling, James [Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060 (United States); Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06032 (United States); School of Chemistry, National University of Ireland, Galway (Ireland)

    2009-10-15

    Covalently linked layers of glucose oxidase, single-wall carbon nanotubes and poly-L-lysine on pyrolytic graphite resulted in a stable biofuel cell anode featuring direct electron transfer from the enzyme. Catalytic response observed upon addition of glucose was due to electrochemical oxidation of FADH{sub 2} under aerobic conditions. The electrode potential depended on glucose concentration. This system has essential attributes of an anode in a mediator-free biocatalytic fuel cell. (author)

  15. Development of Nanosized/Nanostructured Silicon as Advanced Anodes for Lithium-Ion Cells

    Science.gov (United States)

    Wu, James J.

    2015-01-01

    NASA is developing high energy and high capacity Li-ion cell and battery designs for future exploration missions under the NASA Advanced Space Power System (ASPS) Program. The specific energy goal is 265 Wh/kg at 10 C. center dot Part of effort for NASA advanced Li-ion cells ? Anode: Silicon (Si) as an advanced anode. ? Electrolyte: advanced electrolyte with flame-retardant additives for enhanced performance and safety (NASA JPL).

  16. Si nanoparticle-decorated Si nanowire networks for Li-ion battery anodes

    KAUST Repository

    Hu, Liangbing

    2011-01-01

    We designed and fabricated binder-free, 3D porous silicon nanostructures for Li-ion battery anodes, where Si nanoparticles electrically contact current collectors via vertically grown silicon nanowires. When compared with a Si nanowire anode, the areal capacity was increased by a factor of 4 without having to use long, high temperature steps under vacuum that vapour-liquid-solid Si nanowire growth entails. © 2011 The Royal Society of Chemistry.

  17. Design, construction and quality control of resistive-Micromegas anode boards for the ATLAS experiment

    Science.gov (United States)

    Kuger, F.; Iengo, P.

    2018-02-01

    For the upcoming upgrade of the forward muon stations of the ATLAS detector, 1280m2 of Micromegas chambers have to be constructed. The industrialization of anode board production is an essential precondition. Design and construction methods of these boards have been optimized towards mass production. In parallel quality control procedures have been developed and established. The first set of large size Micromegas anode boards has finally been produced in industries and demonstrates the feasibility of the project on full-scale.

  18. SnSe2 2D Anodes for Advanced Sodium Ion Batteries

    KAUST Repository

    Zhang, Fan

    2016-08-22

    A simple synthesis method to prepare pure SnSe2 nanosheet anodes for Na ion batteries is reported. The SnSe2 2D sheets achieve a stable and reversible specific capacity of 515 mA h g-1 after 100 cycles, with excellent rate performance. The sodiation and desodiation process in this anode material is shown to occur via a combination of conversion and alloying reactions.

  19. Stability of Ni–yttria stabilized zirconia anodes based on Ni-impregnation

    DEFF Research Database (Denmark)

    Klemensø, Trine; Thydén, Karl Tor Sune; Chen, Ming

    2010-01-01

    Sintering of Ni is a key stability issue for Ni–YSZ anodes, and especially infiltration based electrodes. The potential of MgO, Al2O3, TiO2, CeO2 and Ce0.90Gd0.10O1.95 (CGO10) as sintering inhibitors was investigated for infiltrated Ni based anode structures. The structures were prepared from tap...

  20. Morphology and stress at silicon-glass interface in anodic bonding

    International Nuclear Information System (INIS)

    Tang, Jiali; Cai, Cheng; Ming, Xiaoxiang; Yu, Xinhai; Zhao, Shuangliang; Tu, Shan-Tung; Liu, Honglai

    2016-01-01

    Highlights: • Amorphous SiO 2 is the most probable silica morphology generated in anodic bonding. • Amorphous SiO 2 thickness at the interface is at least 2 nm for 90 min anodic bonding. • Silicon oxidation rate at the interface is 0.022 nm min −1 from 30 to 90 min. - Abstract: The morphologies and structural details of formed silica at the interface of silicon-glass anodic bonding determine the stress at the interface but they have been rarely clarified. In this study, a miniaturized anodic bonding device was developed and coupled with a Raman spectrometer. The silicon-glass anodic bonding was carried out and the evolution of the stress at the bonding interface was measured in situ by a Raman spectrometer. In addition, large-scale atomistic simulations were conducted by considering the formed silica with different morphologies. The most conceivable silica morphology was identified as the corresponding silicon-glass interfacial stress presents qualitatively agreement with the experimental observation. It was found that amorphous SiO 2 is the silica morphology generated in anodic bonding. The amorphous SiO 2 thickness is at least 2 nm in the case of 90 min anodic bonding at 400 °C with the DC voltage of −1000 V. The combination of experimental and simulation results can ascertain the silicon oxidation reaction rate in anodic bonding process, and under the above-mentioned condition, the reaction rate was estimated as 0.022 nm min −1 from 30 to 90 min.

  1. Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

    Science.gov (United States)

    Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

    2017-12-01

    In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

  2. Graphene–sponges as high-performance low-cost anodes for microbial fuel cells

    KAUST Repository

    Xie, Xing

    2012-01-01

    A high-performance microbial fuel cell (MFC) anode was constructed from inexpensive materials. Key components were a graphene-sponge (G-S) composite and a stainless-steel (SS) current collector. Anode fabrication is simple, scalable, and environmentally friendly, with low energy inputs. The SS current collector improved electrode conductivity and decreased voltage drop and power loss. The resulting G-S-SS composite electrode appears promising for large-scale applications. © 2012 The Royal Society of Chemistry.

  3. The anodization synthesis of copper oxide nanosheet arrays and their photoelectrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Xia [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zheng, Hongmei [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China); Xu, Guangqing, E-mail: gqxu1979@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China); Zhao, Jiebo [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Cui, Lihua [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); School of Materials Science and Engineering, Beifang University of Nationalities, Yinchuan 750021 (China); Cui, Jiewu; Qin, Yongqiang; Wang, Yan [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zhang, Yong [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China)

    2017-08-01

    Graphical abstract: Current-time and potential-time curves of the copper foil anodization process, CV of copper substrate in anodization solution and SEM morphologies of anodization products on Cu substrates obtained at different time. - Highlights: • Copper oxides nanosheet arrays were achieved via anodization method. • The growth mechanisms of the copper anodization process were studied. • Photoelectrochemical performances of copper oxides NSAs were studied. - Abstract: We studied the growth of copper oxide nanosheet arrays on copper foil via a simple anodization method. The structures, morphologies, and elemental compositions of the specimens were characterized with an X-ray diffractometer, scanning electron microscope, high resolution transmission electron microscope, and X-ray photoelectron spectrometer. The copper oxide (Cu{sub 2}O and CuO) nanosheet arrays were comprised of 30-nm-thick nanosheets that stand vertically on the Cu substrate. The anodizing parameters, such as the current density, temperature, and polyethylene glycol concentration, were optimized to obtain the regular nanosheet arrays. The optical absorption properties of the anodized products were evaluated using a diffuse reflectance spectrometer, and broad and strong optical absorption bands arising from the UV to visible region were observed. The photoelectrochemical performance of the nanosheet arrays was measured with chronoamperometry and cyclic voltammetry on an electrochemical workstation equipped with a Xe lamp (wavelength >400 nm). A negative photocurrent was obtained due to the p-type semiconductor of the copper oxides. The copper oxide nanosheet arrays achieve the highest photocurrent of 0.4 mA/cm{sup 2} at the current density of 1.0 A/dm{sup 2}, temperature of 70 °C, and polyethylene glycol concentration of 0.5 g/L.

  4. Morphology and stress at silicon-glass interface in anodic bonding

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jiali [Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical Engineering, East China University of Science and Technology, Shanghai 200237 (China); Cai, Cheng [State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai (China); Ming, Xiaoxiang [Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical Engineering, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai (China); Yu, Xinhai, E-mail: yxhh@ecust.edu.cn [Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical Engineering, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Shuangliang, E-mail: szhao@ecust.edu.cn [State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai (China); Tu, Shan-Tung [Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical Engineering, East China University of Science and Technology, Shanghai 200237 (China); Liu, Honglai [State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai (China)

    2016-11-30

    Highlights: • Amorphous SiO{sub 2} is the most probable silica morphology generated in anodic bonding. • Amorphous SiO{sub 2} thickness at the interface is at least 2 nm for 90 min anodic bonding. • Silicon oxidation rate at the interface is 0.022 nm min{sup −1} from 30 to 90 min. - Abstract: The morphologies and structural details of formed silica at the interface of silicon-glass anodic bonding determine the stress at the interface but they have been rarely clarified. In this study, a miniaturized anodic bonding device was developed and coupled with a Raman spectrometer. The silicon-glass anodic bonding was carried out and the evolution of the stress at the bonding interface was measured in situ by a Raman spectrometer. In addition, large-scale atomistic simulations were conducted by considering the formed silica with different morphologies. The most conceivable silica morphology was identified as the corresponding silicon-glass interfacial stress presents qualitatively agreement with the experimental observation. It was found that amorphous SiO{sub 2} is the silica morphology generated in anodic bonding. The amorphous SiO{sub 2} thickness is at least 2 nm in the case of 90 min anodic bonding at 400 °C with the DC voltage of −1000 V. The combination of experimental and simulation results can ascertain the silicon oxidation reaction rate in anodic bonding process, and under the above-mentioned condition, the reaction rate was estimated as 0.022 nm min{sup −1} from 30 to 90 min.

  5. Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin

    2012-01-01

    An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3_δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell...

  6. Chemically Etched Silicon Nanowires as Anodes for Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    West, Hannah Elise [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This study focused on silicon as a high capacity replacement anode for Lithium-ion batteries. The challenge of silicon is that it expands ~270% upon lithium insertion which causes particles of silicon to fracture, causing the capacity to fade rapidly. To account for this expansion chemically etched silicon nanowires from the University of Maine were studied as anodes. They were built into electrochemical half-cells and cycled continuously to measure the capacity and capacity fade.

  7. Processing of copper anodic-slimes for extraction of valuable metals.

    Science.gov (United States)

    Amer, A M

    2003-01-01

    This work focuses on processing of anodic slimes obtained from an Egyptian copper electrorefining plant. The anodic slimes are characterized by high concentrations of copper, lead, tin and silver. The proposed hydrometallurgical process consists of two leaching stages for the extraction of copper (H(2)SO(4)-O(2)) and silver (thiourea-Fe3+), and pyrometallurgical treatment of the remaining slimes for production of Pb-Sn soldering alloy. Factors affecting both the leaching and smelting stages were studied.

  8. Detection of Chlorine in a Non-aqueous Solution via Anodic Oxidation and a Photochemical Reaction.

    Science.gov (United States)

    Nakagawa, Shogo; Nishimura, Hajime; Kodera, Fumihiro

    2018-01-01

    In this study, we developed a new chlorine gas detection method using anodic oxidation and a photochemical reaction. Chlorine gas was temporarily solvated with an aprotic polar solvent having an extensive potential range in the positive direction, and the solvated chlorine molecule was detected by an anodic oxidation reaction. In addition, when combined with ultraviolet light irradiation, we could detect high sensitivity using the photochemical reaction.

  9. Effect of the anode material on the X-ray spectrum of micropinch discharge plasma

    Science.gov (United States)

    Grigoryeva, I. G.; Savjolov, A. S.; Salakhutdinov, G. Kh.

    2017-07-01

    The effect of the elemental composition of the anode material on the parameters and X-ray spectrum of micropinch discharge plasma have been studied using a low-inductance vacuum spark device. It is shown that the plasma electron temperature T e and intensity of hard X-ray emission increase with increasing nuclear charge number Z of the anode material of the discharge system.

  10. Kinetic investigation of oxygen evolution at titanium-ruthenium oxide anodes. Oxygen evolution kinetics at RuO2 and titaniumruthenium oxide anodes in chloride solutions

    International Nuclear Information System (INIS)

    Kokoulina, D.V.

    1986-01-01

    Oxygen evolution kinetics was studied at 70 degrees C at RuO 2 and titaniumruthenium oxide anodes in chlorinated chloride solutions (1 M NaCl, pH 1.4 to 2.25) by recording polarization curves. The reaction orders were determined. The kinetics of anodic oxygen evolution is important for an understanding of electrode behavior and for an estimate of possible current yields of oxygen under the different conditions of electrolysis of NaCl solutions. The results obtained demonstrate that substantial oxygen evolution can occur in chlorinated chloride solutions at active electrodes because of the coupled reaction of chlorine reduction

  11. Theoretical Limits of Energy Density in Silicon-Carbon Composite Anode Based Lithium Ion Batteries.

    Science.gov (United States)

    Dash, Ranjan; Pannala, Sreekanth

    2016-06-17

    Silicon (Si) is under consideration as a potential next-generation anode material for the lithium ion battery (LIB). Experimental reports of up to 40% increase in energy density of Si anode based LIBs (Si-LIBs) have been reported in literature. However, this increase in energy density is achieved when the Si-LIB is allowed to swell (volumetrically expand) more than graphite based LIB (graphite-LIB) and beyond practical limits. The volume expansion of LIB electrodes should be negligible for applications such as automotive or mobile devices. We determine the theoretical bounds of Si composition in a Si-carbon composite (SCC) based anode to maximize the volumetric energy density of a LIB by constraining the external dimensions of the anode during charging. The porosity of the SCC anode is adjusted to accommodate the volume expansion during lithiation. The calculated threshold value of Si was then used to determine the possible volumetric energy densities of LIBs with SCC anode (SCC-LIBs) and the potential improvement over graphite-LIBs. The level of improvement in volumetric and gravimetric energy density of SCC-LIBs with constrained volume is predicted to be less than 10% to ensure the battery has similar power characteristics of graphite-LIBs.

  12. Development and Testing of High Surface Area Iridium Anodes for Molten Oxide Electrolysis

    Science.gov (United States)

    Shchetkovskiy, Anatoliy; McKechnie, Timothy; Sadoway, Donald R.; Paramore, James; Melendez, Orlando; Curreri, Peter A.

    2010-01-01

    Processing of lunar regolith into oxygen for habitat and propulsion is needed to support future space missions. Direct electrochemical reduction of molten regolith is an attractive method of processing, because no additional chemical reagents are needed. The electrochemical processing of molten oxides requires high surface area, inert anodes. Such electrodes need to be structurally robust at elevated temperatures (1400-1600?C), be resistant to thermal shock, have good electrical conductivity, be resistant to attack by molten oxide (silicate), be electrochemically stable and support high current density. Iridium with its high melting point, good oxidation resistance, superior high temperature strength and ductility is the most promising candidate for anodes in high temperature electrochemical processes. Several innovative concepts for manufacturing such anodes by electrodeposition of iridium from molten salt electrolyte (EL-Form? process) were evaluated. Iridium electrodeposition to form of complex shape components and coating was investigated. Iridium coated graphite, porous iridium structure and solid iridium anodes were fabricated. Testing of electroformed iridium anodes shows no visible degradation. The result of development, manufacturing and testing of high surface, inert iridium anodes will be presented.

  13. Development of a niobium-doped titania inert anode for titanium electrowinning in molten chloride salts.

    Science.gov (United States)

    Snook, Graeme A; McGregor, Katherine; Urban, Andrew J; Lanyon, Marshall R; Donelson, R; Pownceby, Mark I

    2016-08-15

    The direct electrochemical reduction of solid titanium dioxide in a chloride melt is an attractive method for the production of titanium metal. It has been estimated that this type of electrolytic approach may reduce the costs of producing titanium sponge by more than half, with the additional benefit of a smaller environmental footprint. The process utilises a consumable carbon anode which releases a mixture of CO2 and CO gas during electrolysis, but suffers from low current efficiency due to the occurrence of parasitic side reactions involving carbon. The replacement of the carbon anode with a cheap, robust inert anode offers numerous benefits that include: elimination of carbon dioxide emissions, more efficient cell operation, opportunity for three-dimensional electrode configurations and reduced electrode costs. This paper reports a study of Nb-doped titania anode materials for inert anodes in a titanium electrolytic reduction cell. The study examines the effect of niobium content and sintering conditions on the performance of Nb-doped TiO2 anodes in laboratory-scale electrolysis tests. Experimental findings, including performance in a 100 h laboratory electrolysis test, are described.

  14. Removal of arsenic and antimony from anode slime by vacuum dynamic flash reduction.

    Science.gov (United States)

    Lin, Deqiang; Qiu, Keqiang

    2011-04-15

    Anode slime is an important material of recycling precious metals. Up to now, treating the arsenic- and antimony-rich anode slime by conventional processes has the following problems: its economic and environmental effect is less than satisfactory, and the removal effect of arsenic and antimony from anode slime in present processes is not all that could be desired. Therefore, vacuum dynamic flash reduction, a new process for treating arsenic- and antimony-rich anode slime, was investigated in this work. During vacuum dynamic flash reduction, silver from the arsenic- and antimony-rich anode slime was left behind in the distilland as the silver alloy, and trivalent oxides of arsenic and antimony were evaporated in the distillate. The experimental results showed that the evaporation percent of the arsenic- and antimony-rich anode slime was 65.6%. Namely, 98.92% by weight of arsenic and 93.67% by weight of antimony can be removed under the following experimental conditions: temperature of 1083 K, vacuum evaporation time of 60 min, and air flow rate of 400 mL/min corresponding to the residual gas pressure of 250 Pa. Moreover, vacuum treatment eliminates much of the air pollution and material losses associated with other conventional treatment methods.

  15. Contrastive study of anodic oxidation on carbon fibers and graphite fibers

    International Nuclear Information System (INIS)

    Liu Xin; Yang Changling; Lu Yonggen

    2012-01-01

    Anodic oxidation of polyacrylonitrile (PAN) graphite fibers was investigated in comparison with that of carbon fibers. The mechanical and interfacial properties of the treated fibers along with their surface structures were studied with X-ray photoelectron spectroscopy, atomic force microscope, contact angle analyzer, tensile strength instrument and Raman spectrometer. The results show that the graphite fibers were inactive during anodic oxidation for the higher graphitic carbon, while the carbon fibers were active and the surface oxygen content got saturated soon. The dynamics of anodic oxidation for the fibers can be described by a homogenous thickness reduction model, which indicated that the kinetic constant of anodic oxidation for the graphite fibers was only one sixth of that for the carbon fibers. Surface roughness contributed to the improvement on fiber/matrix adhesion as well as the surface oxygen content. The achievement of the surface treatment was proved by Raman spectroscopy mapping the stress of the fiber inside an epoxy resin droplet. The increase of interfacial shear strength from the untreated graphite fibers to the anodized graphite fibers was 160% (from 65 to 170 MPa), much higher than 70% that from untreated carbon fibers to the anodized ones (from 135 to 230 MPa).

  16. Contrastive study of anodic oxidation on carbon fibers and graphite fibers

    Science.gov (United States)

    Liu, Xin; Yang, Changling; Lu, Yonggen

    2012-03-01

    Anodic oxidation of polyacrylonitrile (PAN) graphite fibers was investigated in comparison with that of carbon fibers. The mechanical and interfacial properties of the treated fibers along with their surface structures were studied with X-ray photoelectron spectroscopy, atomic force microscope, contact angle analyzer, tensile strength instrument and Raman spectrometer. The results show that the graphite fibers were inactive during anodic oxidation for the higher graphitic carbon, while the carbon fibers were active and the surface oxygen content got saturated soon. The dynamics of anodic oxidation for the fibers can be described by a homogenous thickness reduction model, which indicated that the kinetic constant of anodic oxidation for the graphite fibers was only one sixth of that for the carbon fibers. Surface roughness contributed to the improvement on fiber/matrix adhesion as well as the surface oxygen content. The achievement of the surface treatment was proved by Raman spectroscopy mapping the stress of the fiber inside an epoxy resin droplet. The increase of interfacial shear strength from the untreated graphite fibers to the anodized graphite fibers was 160% (from 65 to 170 MPa), much higher than 70% that from untreated carbon fibers to the anodized ones (from 135 to 230 MPa).

  17. Highly reversible lead-carbon battery anode with lead grafting on the carbon surface

    KAUST Repository

    Yin, Jian

    2018-03-27

    A novel C/Pb composite has been successfully prepared by electroless plating to reduce the hydrogen evolution and achieve the high reversibility of the anode of lead-carbon battery (LCB). The deposited lead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Because lead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogen evolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead. Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge–discharge reversibility, which is attributed to the good connection between carbon additives and lead that has been stuck on the surface of C/Pb composite during the preparation process. The addition of C/Pb composite maintains a solid anode structure with high specific surface area and power volume, and thereby, it plays a significant role in the highly reversible lead-carbon anode.

  18. Effects of assistant anode on planar inductively coupled magnetized argon plasma in plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Tang, Deli; Chu, Paul K.

    2003-01-01

    The enhancement of planar radio frequency (RF) inductively coupled argon plasma is studied in the presence of an assistant anode and an external magnetic field at low pressure. The influence of the assistant anode and magnetic field on the efficiency of RF power absorption and plasma parameters is investigated. An external axial magnetic field is coupled into the plasma discharge region by an external electromagnetic coil outside the discharge chamber and an assistant cylindrical anode is inserted into the discharge chamber to enhance the plasma discharge. The plasma parameters and density profile are measured by an electrostatic Langmuir probe at different magnetic fields and anode voltages. The RF power absorption by the plasma can be effectively enhanced by the external magnetic field compared with the nonmagnetized discharge. The plasma density can be further increased by the application of a voltage to the assistant anode. Owing to the effective power absorption and enhanced plasma discharge by the assistant anode in a longitudinal magnetic field, the plasma density can be enhanced by more than a factor of two. Meanwhile, the nonuniformity of the plasma density is less than 10% and it can be achieved in a process chamber with a diameter of 600 mm

  19. Silicon-Based Anodes for Lithium-Ion Batteries: From Fundamentals to Practical Applications.

    Science.gov (United States)

    Feng, Kun; Li, Matthew; Liu, Wenwen; Kashkooli, Ali Ghorbani; Xiao, Xingcheng; Cai, Mei; Chen, Zhongwei

    2018-02-01

    Silicon has been intensively studied as an anode material for lithium-ion batteries (LIB) because of its exceptionally high specific capacity. However, silicon-based anode materials usually suffer from large volume change during the charge and discharge process, leading to subsequent pulverization of silicon, loss of electric contact, and continuous side reactions. These transformations cause poor cycle life and hinder the wide commercialization of silicon for LIBs. The lithiation and delithiation behaviors, and the interphase reaction mechanisms, are progressively studied and understood. Various nanostructured silicon anodes are reported to exhibit both superior specific capacity and cycle life compared to commercial carbon-based anodes. However, some practical issues with nanostructured silicon cannot be ignored, and must be addressed if it is to be widely used in commercial LIBs. This Review outlines major impactful work on silicon-based anodes, and the most recent research directions in this field, specifically, the engineering of silicon architectures, the construction of silicon-based composites, and other performance-enhancement studies including electrolytes and binders. The burgeoning research efforts in the development of practical silicon electrodes, and full-cell silicon-based LIBs are specially stressed, which are key to the successful commercialization of silicon anodes, and large-scale deployment of next-generation high energy density LIBs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Comparison in performance of sediment microbial fuel cells according to depth of embedded anode.

    Science.gov (United States)

    An, Junyeong; Kim, Bongkyu; Nam, Jonghyeon; Ng, How Yong; Chang, In Seop

    2013-01-01

    Five rigid graphite plates were embedded in evenly divided sections of sediment, ranging from 2 cm (A1) to 10 cm (A5) below the top sediment layer. The maximum power and current of the MFCs increased in depth order; however, despite the increase in the internal resistance, the power and current density of the A5 MFC were 2.2 and 3.5 times higher, respectively, than those of the A1 MFC. In addition, the anode open circuit potentials (OCPs) of the sediment microbial fuel cells (SMFCs) became more negative with sediment depth. Based on these results, it could be then concluded that as the anode-embedding depth increases, that the anode environment is thermodynamically and kinetically favorable to anodophiles or electrophiles. Therefore, the anode-embedding depth should be considered an important parameter that determines the performance of SMFCs, and we posit that the anode potential could be one indicator for selecting the anode-embedding depth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Biological capacitance studies of anodes in microbial fuel cells using electrochemical impedance spectroscopy.

    Science.gov (United States)

    Lu, Zhihao; Girguis, Peter; Liang, Peng; Shi, Haifeng; Huang, Guangtuan; Cai, Lankun; Zhang, Lehua

    2015-07-01

    It is known that cell potential increases while anode resistance decreases during the start-up of microbial fuel cells (MFCs). Biological capacitance, defined as the apparent capacitance attributed to biological activity including biofilm production, plays a role in this phenomenon. In this research, electrochemical impedance spectroscopy was employed to study anode capacitance and resistance during the start-up period of MFCs so that the role of biological capacitance was revealed in electricity generation by MFCs. It was observed that the anode capacitance ranged from 3.29 to 120 mF which increased by 16.8% to 18-20 times over 10-12 days. Notably, lowering the temperature and arresting biological activity via fixation by 4% para formaldehyde resulted in the decrease of biological capacitance by 16.9 and 62.6%, indicating a negative correlation between anode capacitance and anode resistance of MFCs. Thus, biological capacitance of anode should play an important role in power generation by MFCs. We suggest that MFCs are not only biological reactors and/or electrochemical cells, but also biological capacitors, extending the vision on mechanism exploration of electron transfer, reactor structure design and electrode materials development of MFCs.

  2. Electrochemical coating of dental implants with anodic porous titania for enhanced osteointegration

    Directory of Open Access Journals (Sweden)

    Amirreza Shayganpour

    2015-11-01

    Full Text Available Clinical long-term osteointegration of titanium-based biomedical devices is the main goal for both dental and orthopedical implants. Both the surface morphology and the possible functionalization of the implant surface are important points. In the last decade, following the success of nanostructured anodic porous alumina, anodic porous titania has also attracted the interest of academic researchers. This material, investigated mainly for its photocatalytic properties and for applications in solar cells, is usually obtained from the anodization of ultrapure titanium. We anodized dental implants made of commercial grade titanium under different experimental conditions and characterized the resulting surface morphology with scanning electron microscopy equipped with an energy dispersive spectrometer. The appearance of nanopores on these implants confirm that anodic porous titania can be obtained not only on ultrapure and flat titanium but also as a conformal coating on curved surfaces of real objects made of industrial titanium alloys. Raman spectroscopy showed that the titania phase obtained is anatase. Furthermore, it was demonstrated that by carrying out the anodization in the presence of electrolyte additives such as magnesium, these can be incorporated into the porous coating. The proposed method for the surface nanostructuring of biomedical implants should allow for integration of conventional microscale treatments such as sandblasting with additive nanoscale patterning. Additional advantages are provided by this material when considering the possible loading of bioactive drugs in the porous cavities.

  3. Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Yoon-Jae [Samsung Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Park, Man-Jin [Research Institute of Nano Manufacturing System, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Moon, Dae Won [Nanobio Fusion Research Center, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

    2012-02-15

    Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

  4. Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

    International Nuclear Information System (INIS)

    Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, Yoon-Jae; Park, Man-Jin; Moon, Dae Won

    2012-01-01

    Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m 2 SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

  5. Preparation and Evaluation of Multi-Layer Anodes of Solid Oxide Fuel Cell

    Science.gov (United States)

    Santiago, Diana; Farmer, Serene C.; Setlock, John A.

    2012-01-01

    The development of an energy device with abundant energy generation, ultra-high specific power density, high stability and long life is critical for enabling longer missions and for reducing mission costs. Of all different types of fuel cells, the solid oxide fuel cells (SOFC) is a promising high temperature device that can generate electricity as a byproduct of a chemical reaction in a clean way and produce high quality heat that can be used for other purposes. For aerospace applications, a power-to-weight of (is) greater than 1.0 kW/kg is required. NASA has a patented fuel cell technology under development, capable of achieving the 1.0 kW/kg figure of merit. The first step toward achieving these goals is increasing anode durability. The catalyst plays an important role in the fuel cells for power generation, stability, efficiency and long life. Not only the anode composition, but its preparation and reduction are key to achieving better cell performance. In this research, multi-layer anodes were prepared varying the chemistry of each layer to optimize the performance of the cells. Microstructure analyses were done to the new anodes before and after fuel cell operation. The cells' durability and performance were evaluated in 200 hrs life tests in hydrogen at 850 C. The chemistry of the standard nickel anode was modified successfully reducing the anode degradation from 40% to 8.4% in 1000 hrs and retaining its microstructure.

  6. Effect of Graphene-Graphene Oxide Modified Anode on the Performance of Microbial Fuel Cell

    Science.gov (United States)

    Yang, Na; Ren, Yueping; Li, Xiufen; Wang, Xinhua

    2016-01-01

    The inferior hydrophilicity of graphene is an adverse factor to the performance of the graphene modified anodes (G anodes) in microbial fuel cells (MFCs). In this paper, different amounts of hydrophilic graphene oxide (GO) were doped into the modification layers to elevate the hydrophilicity of the G anodes so as to further improve their performance. Increasing the GO doped ratio from 0.15 mg·mg−1 to 0.2 mg·mg−1 and 0.25 mg·mg−1, the static water contact angle (θc) of the G-GO anodes decreased from 74.2 ± 0.52° to 64.6 ± 2.75° and 41.7 ± 3.69°, respectively. The G-GO0.2 anode with GO doped ratio of 0.2 mg·mg−1 exhibited the optimal performance and the maximum power density (Pmax) of the corresponding MFC was 1100.18 mW·m−2, 1.51 times higher than that of the MFC with the G anode. PMID:28335302

  7. Yolk-shell structured Sb@C anodes for high energy Na-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Song, Junhua; Yan, Pengfei; Luo, Langli; Qi, Xingguo; Rong, Xiaohui; Zheng, Jianming; Xiao, Biwei; Feng, Shuo; Wang, Chongmin; Hu, Yong-Sheng; Lin, Yuehe; Sprenkle, Vincent L.; Li, Xiaolin

    2017-10-01

    Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb2O3 from carbon coated Sb2O3 nanoparticles can accommodate the Sb swelling upon sodiation and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~554 mAh•g-1, good rate capability (315 mhA•g-1 at 10C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na0.9[Cu0.22Fe0.30Mn0.48]O2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~130 Wh•kg-1 (based on the total mass of cathode and anode) in the voltage range of 2.0-4.0 V, ~1.5 times energy of full-cells with similar design using hard carbon anodes.

  8. Development and testing of immersed-Bz diodes with cryogenic anodes

    International Nuclear Information System (INIS)

    Bruner, Nichelle Lee; Cordova, Steve Ray; Oliver, Bryan Velten; Portillo, Salvador; Cooper, Graham; Puetz, Elizabeth A.; Johnston, Mark D.; Hahn, Kelly Denise; McLean, John; Molina, Isidro; Droemer, Darryl W.; Welch, Dale R.; Rovang, Dean Curtis; Van De Valde, David M.; Gregerson, Darryl; Maenchen, John Eric; O'Malley, John

    2005-01-01

    Sandia National Laboratories is investigating and developing high-dose, high-brightness flash radiographic sources. The immersed-B z diode employs large-bore, high-field solenoid magnets to help guide and confine an intense electron beam from a needle-like cathode 'immersed' in the axial field of the magnet. The electron beam is focused onto a high-atomic-number target/anode to generate an intense source of bremsstrahlung X-rays. Historically, these diodes have been unable to achieve high dose (> 500 rad (at) m) from a small spot (< 3 mm diameter). It is believed that this limitation is due in part to undesirable effects associated with the interaction of the electron beam with plasmas formed at either the anode or the cathode. Previous research concentrated on characterizing the behavior of diodes, which used untreated, room temperature (RT) anodes. Research is now focused on improving the diode performance by modifying the diode behavior by using cryogenic anodes that are coated in-situ with frozen gases. The objective of these cryogenically treated anodes is to control and limit the ion species of the anode plasma formed and hence the species of the counter-streaming ions that can interact with the electron beam. Recent progress in the development, testing and fielding of the cryogenically cooled immersed diodes at Sandia is described.

  9. Reviving Lithium-Metal Anodes for Next-Generation High-Energy Batteries.

    Science.gov (United States)

    Guo, Yanpeng; Li, Huiqiao; Zhai, Tianyou

    2017-08-01

    Lithium-metal batteries (LMBs), as one of the most promising next-generation high-energy-density storage devices, are able to meet the rigid demands of new industries. However, the direct utilization of metallic lithium can induce harsh safety issues, inferior rate and cycle performance, or anode pulverization inside the cells. These drawbacks severely hinder the commercialization of LMBs. Here, an up-to-date review of the behavior of lithium ions upon deposition/dissolution, and the failure mechanisms of lithium-metal anodes is presented. It has been shown that the primary causes consist of the growth of lithium dendrites due to large polarization and a strong electric field at the vicinity of the anode, the hyperactivity of metallic lithium, and hostless infinite volume changes upon cycling. The recent advances in liquid organic electrolyte (LOE) systems through modulating the local current density, anion depletion, lithium flux, the anode-electrolyte interface, or the mechanical strength of the interlayers are highlighted. Concrete strategies including tailoring the anode structures, optimizing the electrolytes, building artificial anode-electrolyte interfaces, and functionalizing the protective interlayers are summarized in detail. Furthermore, the challenges remaining in LOE systems are outlined, and the future perspectives of introducing solid-state electrolytes to radically address safety issues are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    Directory of Open Access Journals (Sweden)

    Zhaoxiang Chen

    2018-02-01

    Full Text Available Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC composite coating were investigated and compared with the anodic TiO2 mono-film and DLC mono-film. Results show that the DLC deposition significantly decreased the surface roughness and porosity of spark-anodized titanium. The fabricated TiO2/DLC composite coating exhibited a more stable and much lower friction coefficient than anodic TiO2 mono-film. Although the friction coefficient of the composite coating and the DLC mono-film was similar under both light load and heavy load conditions, the wear life of the composite coating was about 43% longer than that of DLC mono-film under heavy load condition. The wear rate of titanium with protective composite coating was much lower than that of titanium with DLC mono-film. The superior low friction coefficient and wear rate of the TiO2/DLC composite coating make it a good candidate as protective coating on titanium alloys.

  11. Superhydrophobic NiTi shape memory alloy surfaces fabricated by anodization and surface mechanical attrition treatment

    Science.gov (United States)

    Ou, Shih-Fu; Wang, Kuang-Kuo; Hsu, Yen-Chi

    2017-12-01

    This paper describes the fabrication of superhydrophobic NiTi shape memory alloy (SMA) surfaces using an environmentally friendly method based on an economical anodizing process. Perfluorooctyltriethoxysilane was used to reduce the surface energy of the anodized surfaces. The wettability, morphology, composition, and microstructure of the surfaces were investigated by scanning electron microscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy. The surface of the treated NiTi SMA exhibited superhydrophobicity, with a water contact angle of 150.6° and sliding angle of 8°. The anodic film on the NiTi SMA comprised of TiO2 and NiO, as well as traces of TiCl3. In addition, before the NiTi SMA was anodized, it underwent a surface mechanical attrition treatment to grain-refine its surface. This method efficiently enhanced the growth rate of the anodic oxide film, and improved the hydrophobic uniformity of the anodized NiTi-SMA-surface.

  12. Nanostructural characterization of large-scale porous alumina fabricated via anodizing in arsenic acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Akiya, Shunta; Kikuchi, Tatsuya, E-mail: kiku@eng.hokudai.ac.jp; Natsui, Shungo; Suzuki, Ryosuke O.

    2017-05-01

    Highlights: • Anodic porous alumina was formed in an arsenic acid solution. • Potential difference (voltage) anodizing at 340 V was achieved. • The porous alumina was slightly ordered under the appropriate conditions. • Pore sealing behavior was not observed in boiling distilled water. • The porous alumina exhibits a white photoluminescence emission under UV irradiation. - Abstract: Anodizing of aluminum in an arsenic acid solution is reported for the fabrication of anodic porous alumina. The highest potential difference (voltage) without oxide burning increased as the temperature and the concentration of the arsenic acid solution decreased, and a high anodizing potential difference of 340 V was achieved. An ordered porous alumina with several tens of cells was formed in 0.1–0.5 M arsenic acid solutions at 310–340 V for 20 h. However, the regularity of the porous alumina was not improved via anodizing for 72 h. No pore sealing behavior of the porous alumina was observed upon immersion in boiling distilled water, and it may be due to the formation of an insoluble complex on the oxide surface. The porous alumina consisted of two different layers: a hexagonal alumina layer that contained arsenic from the electrolyte and a pure alumina honeycomb skeleton. The porous alumina exhibited a white photoluminescence emission at approximately 515 nm under UV irradiation at 254 nm.

  13. Characterization of Raw and Decopperized Anode Slimes from a Chilean Refinery

    Science.gov (United States)

    Melo Aguilera, Evelyn; Hernández Vera, María Cecilia; Viñals, Joan; Graber Seguel, Teófilo

    2016-04-01

    This work characterizes raw and decopperized slimes, with the objective of identifying the phases in these two sub-products. The main phases in copper anodes are metallic copper, including CuO, which are present in free form or associated with the presence of copper selenide or tellurides (Cu2(Se,Te)) and several Cu-Pb-Sb-As-Bi oxides. During electrorefining, the impurities in the anode release and are not deposited in the cathode, part of them dissolving and concentrated in the electrolyte, and others form a raw anode slime that contains Au, Ag, Cu, As, Se, Te and PGM, depending on the composition of the anode. There are several recovery processes, most of which involve acid leaching in the first step to dissolve copper, whose product is decopperized anode slime. SEM analysis revealed that the mineralogical species present in the raw anode slime under study were mainly eucarite (CuAgSe), naumannite (Ag2Se), antimony arsenate (SbAsO4), and lead sulfate (PbSO4). In the case of decopperized slime, the particles were mainly composed of SbAsO4 (crystalline appearance), non-stoichiometric silver selenide (Ag(2- x)Se), and chlorargyrite (AgCl).

  14. Anodization Mechanism on SiC Nanoparticle Reinforced Al Matrix Composites Produced by Power Metallurgy.

    Science.gov (United States)

    Ferreira, Sonia C; Conde, Ana; Arenas, María A; Rocha, Luis A; Velhinho, Alexandre

    2014-12-19

    Specimens of aluminum-based composites reinforced by silicon carbide nanoparticles (Al/SiC np ) produced by powder metallurgy (PM) were anodized under voltage control in tartaric-sulfuric acid (TSA). In this work, the influence of the amount of SiC np on the film growth during anodizing was investigated. The current density versus time response and the morphology of the porous alumina film formed at the composite surface are compared to those concerning a commercial aluminum alloy (AA1050) anodized under the same conditions. The processing method of the aluminum alloys influences the efficiency of the anodizing process, leading to a lower thicknesses for the unreinforced Al-PM alloy regarding the AA1050. The current density versus time response is strongly dependent on the amount of SiC np . The current peaks and the steady-state current density recorded at each voltage step increases with the SiC np volume fraction due to the oxidation of the SiC np . The formation mechanism of the anodic film on Al/SiC np composites is different from that occurring in AA1050, partly due the heterogeneous distribution of the reinforcement particles in the metallic matrix, but also to the entrapment of SiC np in the anodic film.

  15. Invariance of the mobility edge in anodic titanium oxides

    International Nuclear Information System (INIS)

    Tit, N.; Halley, J.W.; Shore, H.B.

    1992-05-01

    We present a theoretical investigation to explain the electronic and optical properties of anodic rutile TiO 2 thin films of different thicknesses (ranging from 5nm to 20nm). There is experimental evidence that the observed gap state at 0.7eV below the edge of conduction-band is due to an oxygen vacancy. For this reason, oxygen vacancies are used as defects in our model. A comparison of the calculated bulk-photoconductivity to photospectroscopy experiment reveals that the films have bulk-like transport properties with a bandgap E g =3.0eV. On the other hand, a fit of the surface density of states to the scanning tunneling microscopy (STM) experiment on the (001) surfaces has suggested a surface defect density of 5% of oxygen vacancies. To resolve this discrepancy, we calculated the dc-conductivity where localization effects are included. Our results show an impurity band formation at about p c =9% of oxygen vacancies. We concluded that the studied films have defect densities below the threshold of impurity band formation. As a consequence the gap states seen in STM are localized (i.e. the oxygen vacancies are playing the role of trapping centers, deep levels) and the mobility edge is invariant. (author). 11 refs, 3 figs

  16. Breathing silicon anodes for durable high-power operations.

    Science.gov (United States)

    Hwang, Chihyun; Joo, Sehun; Kang, Na-Ri; Lee, Ungju; Kim, Tae-Hee; Jeon, Yuju; Kim, Jieun; Kim, Young-Jin; Kim, Ju-Young; Kwak, Sang-Kyu; Song, Hyun-Kon

    2015-09-23

    Silicon anode materials have been developed to achieve high capacity lithium ion batteries for operating smart phones and driving electric vehicles for longer time. Serious volume expansion induced by lithiation, which is the main drawback of silicon, has been challenged by multi-faceted approaches. Mechanically rigid and stiff polymers (e.g. alginate and carboxymethyl cellulose) were considered as the good choices of binders for silicon because they grab silicon particles in a tight and rigid way so that pulverization and then break-away of the active mass from electric pathways are suppressed. Contrary to the public wisdom, in this work, we demonstrate that electrochemical performances are secured better by letting silicon electrodes breathe in and out lithium ions with volume change rather than by fixing their dimensions. The breathing electrodes were achieved by using a polysaccharide (pullulan), the conformation of which is modulated from chair to boat during elongation. The conformational transition of pullulan was originated from its α glycosidic linkages while the conventional rigid polysaccharide binders have β linkages.

  17. Disposable copper-based electrochemical sensor for anodic stripping voltammetry.

    Science.gov (United States)

    Pei, Xing; Kang, Wenjing; Yue, Wei; Bange, Adam; Heineman, William R; Papautsky, Ian

    2014-05-20

    In this work, we report the first copper-based point-of-care sensor for electrochemical measurements demonstrated by zinc determination in blood serum. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Electrochemistry offers a simple approach to metal detection on the microscale, but traditional carbon, gold (Au), or platinum (Pt) electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor features a new low-cost electrode material, copper, which offers simple fabrication and compatibility with microfabrication and PCB processing, while maintaining competitive performance in electrochemical detection. Anodic stripping voltammetry of zinc using our new copper-based sensors exhibited a 140 nM (9.0 ppb) limit of detection (calculated) and sensitivity greater than 1 μA/μM in the acetate buffer. The sensor was also able to determine zinc in a bovine serum extract, and the results were verified with independent sensor measurements. These results demonstrate the advantageous qualities of this lab-on-a-chip electrochemical sensor for clinical applications, which include a small sample volume (μL scale), reduced cost, short response time, and high accuracy at low concentrations of analyte.

  18. Ordered three-dimensional interconnected nanoarchitectures in anodic porous alumina

    Science.gov (United States)

    Martín, Jaime; Martín-González, Marisol; Fernández, Jose Francisco; Caballero-Calero, Olga

    2014-01-01

    Three-dimensional nanostructures combine properties of nanoscale materials with the advantages of being macro-sized pieces when the time comes to manipulate, measure their properties, or make a device. However, the amount of compounds with the ability to self-organize in ordered three-dimensional nanostructures is limited. Therefore, template-based fabrication strategies become the key approach towards three-dimensional nanostructures. Here we report the simple fabrication of a template based on anodic aluminum oxide, having a well-defined, ordered, tunable, homogeneous 3D nanotubular network in the sub 100 nm range. The three-dimensional templates are then employed to achieve three-dimensional, ordered nanowire-networks in Bi2Te3 and polystyrene. Lastly, we demonstrate the photonic crystal behavior of both the template and the polystyrene three-dimensional nanostructure. Our approach may establish the foundations for future high-throughput, cheap, photonic materials and devices made of simple commodity plastics, metals, and semiconductors. PMID:25342247

  19. Electrochemical activity of Geobacter sulfurreducens biofilms on stainless steel anodes

    International Nuclear Information System (INIS)

    Dumas, Claire; Basseguy, Regine; Bergel, Alain

    2008-01-01

    Stainless steel was studied as anode for the biocatalysis of acetate oxidation by biofilms of Geobacter sulfurreducens. Electrodes were individually polarized at different potential in the range -0.20 V to +0.20 V vs. Ag/AgCl either in the same reactor or in different reactors containing acetate as electron donor and no electron acceptor except the working electrode. At +0.20 V vs. Ag/AgCl, the current increased after a 2-day lag period up to maximum current densities around 0.7 A m -2 and 2.4 A m -2 with 5 mM and 10 mM acetate, respectively. No current was obtained during chronoamperometry (CA) at potential values lower than 0.00 V vs. Ag/AgCl, while the cyclic voltammetries (CV) that were performed periodically always detected a fast electron transfer, with the oxidation starting around -0.25 V vs. Ag/AgCl. Epifluorescent microscopy showed that the current recorded by chronoamperometry was linked to the biofilm growth on the electrode surface, while CVs were more likely linked to the cells initially adsorbed from the inoculum. A model was proposed to explain the electrochemical behaviour of the biofilm, which appeared to be controlled by the pioneering adherent cells playing the role of 'electrochemical gate' between the biofilm and the electrode surface

  20. Anodic Lodes and Scrapings as a Source of Electrolytic Manganese

    Directory of Open Access Journals (Sweden)

    Daniel Fernández-González

    2018-03-01

    Full Text Available Manganese is an element of interest in metallurgy, especially in ironmaking and steel making, but also in copper and aluminum industries. The depletion of manganese high grade sources and the environmental awareness have led to search for new manganese sources, such as wastes/by-products of other metallurgies. In this way, we propose the recovery of manganese from anodic lodes and scrapings of the zinc electrolysis process because of their high Mn content (>30%. The proposed process is based on a mixed leaching: a lixiviation-neutralization at low temperature (50 °C, reached due to the exothermic reactions involved in the process and a lixiviation with sulfuric acid at high temperature (150–200 °C, in heated reactor. The obtained solution after the combined process is mainly composed by manganese sulphate. This solution is then neutralized with CaO (or manganese carbonate as a first purification stage, removing H2SO4 and those impurities that are easily removable by controlling pH. Then, the purification of nobler elements than manganese is performed by their precipitation as sulphides. The purified solution is sent to electrolysis where electrolytic manganese is obtained (99.9% Mn. The versatility of the proposed process allows for obtaining electrolytic manganese, oxide of manganese (IV, oxide of manganese (II, or manganese sulphate.

  1. Synergism between anodic oxidation with diamond anodes and heterogeneous catalytic photolysis for the treatment of pharmaceutical pollutants

    Directory of Open Access Journals (Sweden)

    Juan M. Peralta-Hernández

    2016-03-01

    Full Text Available The mineralization of diclofenac and acetaminophen has been studied by single anodic oxidation with boron-doped diamond (AO-BDD using an undivided electrolysis cell, by single heterogeneous catalytic photolysis with titanium dioxide (HCP-TiO2 and by the combination of both advanced oxidation processes. The results show that mineralization can be obtained with either single technology. The type of functional groups of the pollutant does not influence the results of the single AO-BDD process, but it has a significant influence on the results obtained with HCP-TiO2. A clear synergistic effect appears when both processes are combined showing improvements in the oxidation rate of more than 50% for diclofenac and nearly 200% for acetaminophen at the highest current exerted. Results obtained are explained in terms of the production of oxidants on the surface of BDD (primarily peroxodisulfate and the later homogeneous catalytic light decomposition of these oxidants in the bulk. This mechanism is consistent with the larger improvement observed at higher current densities, for which the production of oxidants is promoted.

  2. Comparison of microbial electrolysis cells operated with added voltage or by setting the anode potential

    KAUST Repository

    Nam, Joo-Youn

    2011-08-01

    Hydrogen production in a microbial electrolysis cell (MEC) can be achieved by either setting the anode potential with a potentiostat, or by adding voltage to the circuit with a power source. In batch tests the largest total gas production (46 ± 3 mL), lowest energy input (2.3 ± 0.3 kWh/m 3 of H2 generated), and best overall energy recovery (E+S = 58 ± 6%) was achieved at a set anode potential of EAn = -0.2 V (vs Ag/AgCl), compared to set potentials of -0.4 V, 0 V and 0.2 V, or an added voltage of Eap = 0.6 V. Gas production was 1.4 times higher with EAn = -0.2 V than with Eap = 0.6 V. Methane production was also reduced at set anode potentials of -0.2 V and higher than the other operating conditions. Continuous flow operation of the MECs at the optimum condition of EAn = -0.2 V initially maintained stable hydrogen gas production, with 68% H2 and 21% CH4, but after 39 days the gas composition shifted to 55% H2 and 34% CH 4. Methane production was not primarily anode-associated, as methane was reduced to low levels by placing the anode into a new MEC housing. These results suggest that MEC performance can be optimized in terms of hydrogen production rates and gas composition by setting an anode potential of -0.2 V, but that methanogen proliferation must be better controlled on non-anodic surfaces. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  3. Enhanced removal of petroleum hydrocarbons using a bioelectrochemical remediation system with pre-cultured anodes

    Energy Technology Data Exchange (ETDEWEB)

    Venkidusamy, Krishnaveni [Centre for Environmental Risk Assessment and Remediation (CERAR), University of South (Australia); CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095 (Australia); Megharaj, Mallavarapu, E-mail: megh.mallavarapu@newcastle.edu.au [Centre for Environmental Risk Assessment and Remediation (CERAR), University of South (Australia); CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095 (Australia); Global Centre for Environmental Remediation, Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308 (Australia); Marzorati, Massimo [Laboratory for Microbial Ecology and Technology (LabMET), Gent University, 9000 Gent (Belgium); Lockington, Robin [Centre for Environmental Risk Assessment and Remediation (CERAR), University of South (Australia); CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095 (Australia); Naidu, Ravi [Centre for Environmental Risk Assessment and Remediation (CERAR), University of South (Australia); CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095 (Australia); Global Centre for Environmental Remediation, Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308 (Australia)

    2016-01-01

    Bioelectrochemical remediation (BER) systems such as microbial fuel cells (MFCs) have recently emerged as a green technology for the effective remediation of petroleum hydrocarbon contaminants (PH) coupled with simultaneous energy recovery. Recent research has shown that biofilms previously enriched for substrate degrading bacteria resulted in excellent performance in terms of substrate removal and electricity generation but the effects on hydrocarbon contaminant degradation were not examined. Here we investigate the differences between enriched biofilm anodes and freshly inoculated new anodes in diesel fed single chamber mediatorless microbial fuel cells (DMFC) using various techniques for the enhancement of PH contaminant remediation with concomitant electricity generation. An anodophilic microbial consortium previously selected for over a year through continuous culturing with a diesel concentration of about 800 mg l{sup −1} and which now showed complete removal of this concentration of diesel within 30 days was compared to that of a freshly inoculated new anode MFC (showing 83.4% removal of diesel) with a simultaneous power generation of 90.81 mW/m{sup 2} and 15.04 mW/m{sup 2} respectively. The behaviour of pre-cultured anodes at a higher concentration of PH (8000 mg l{sup −1}) was also investigated. Scanning electron microscopy observation revealed a thick biofilm covering the pre-cultured anodic electrode but not the anode from the freshly inoculated MFC. High resolution imaging showed the presence of thin 60 nm diametre pilus-like projections emanating from the cells. Anodic microbial community profiling confirmed that the selection for diesel degrading exoelectrogenic bacteria had occurred. Identification of a biodegradative gene (alkB) provided strong evidence of the catabolic pathway used for diesel degradation in the DMFCs.

  4. Anodic behavior of stainless-steel substrate in organic electrolyte solutions containing different lithium salts

    International Nuclear Information System (INIS)

    Furukawa, Kazuki; Yoshimoto, Nobuko; Egashira, Minato; Morita, Masayuki

    2014-01-01

    Highlights: • We investigated anodic behavior of stainless-steel in organic electrolytes for advanced capacitor. • Anion of the electrolyte affected the anodic stability of the alloy. • Anodic passivation occurs in LiPF 6 solution but pitting or active dissolution proceeds in other electrolyte solutions. • Fluoride source in the solution contributes to forming a stable surface layer on the stainless steel. - Abstract: The anodic behavior of austenitic stainless-steel, SUS304, as a current collector of positive electrode in lithium-ion battery/capacitor has been investigated in organic electrolyte solutions based on a mixed alkyl carbonate solvent with different lithium salts. Stable passivation characteristics were observed for the stainless-steel in the LiPF 6 solution, but pitting corrosion or active dissolution proceeded in the solutions containing other anions, BF 4 - , (CF 3 SO 2 ) 2 N - (TFSA - ) and ClO 4 - . The mass ratios of the dissolved metal species in the solutions of LiTFSA and LiClO 4 were equivalent to that of the alloy composition, which suggests that no preferential dissolution occurs during the anodic polarization in these electrolyte solutions. An HF component formed by decomposition of PF 6 - with the contaminate water will act as an F - source for the formation of a surface fluoride layer, that will contribute to the anodic stability of SUS304 in the LiPF 6 solution. The anodic corrosion in the LiTFSA solution was suppressed in part by mixing the PF 6 salt or adding HF in the electrolyte

  5. Electrocatalytic properties and stability of titanium anodes activated by the inorganic sol–gel procedure

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2008-10-01

    Full Text Available The properties of activated titanium anodes, RuO2–TiO2/Ti and RuO2–TiO2–IrO2/Ti, prepared from oxide sols by the sol–gel procedure, are reviewed. RuO2 and TiO2 sols were synthesized by forced hydrolysis of the corresponding chlorides in acid medium. The morphology of the prepared sols was investigated by transmission electron microscopy. The chemical composition of the RuO2 sol was determined by X-ray diffraction and thermogravimetric analysis. The loss of electrocatalytic activity of a RuO2–TiO2/Ti anode during an accelerated stability test was investigated by examination of the changes in the electrochemical characteristics in the potential region of the chlorine and oxygen evolution reaction, as well as on the open circuit potential. These electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and polarization measurements. The changes in electrochemical characteristics of the anode prepared by the sol–gel procedure were compared to the changes registered for an anode prepared by the traditional thermal decomposition of metal chlorides. The comparison indicated that the main cause for the activity loss of the sol–gel prepared anode was the electrochemical dissolution of RuO2, while in the case of thermally prepared anode the loss was mainly caused by the formation of an insulating TiO2 layer in the coating/Ti substrate interphase. The results of an accelerated stability test on RuO2–TiO2/Ti and RuO2–TiO2–IrO2/Ti anodes showed that the ternary coating is considerably more stable than the binary one, which is the consequence of the greater stability of IrO2 in comparison to RuO2.

  6. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    International Nuclear Information System (INIS)

    Zhang, Dongya; Dong, Guangneng; Chen, Yinjuan; Zeng, Qunfeng

    2014-01-01

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm 2 for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  7. CASTOR: Cathode/Anode Satellite Thruster for Orbital Repositioning

    Science.gov (United States)

    Mruphy, Gloria A.

    2010-01-01

    The purpose of CASTOR (Cathode/Anode Satellite Thruster for Orbital Repositioning) satellite is to demonstrate in Low Earth Orbit (LEO) a nanosatellite that uses a Divergent Cusped Field Thruster (DCFT) to perform orbital maneuvers representative of an orbital transfer vehicle. Powered by semi-deployable solar arrays generating 165W of power, CASTOR will achieve nearly 1 km/s of velocity increment over one year. As a technology demonstration mission, success of CASTOR in LEO will pave the way for a low cost, high delta-V orbital transfer capability for small military and civilian payloads in support of Air Force and NASA missions. The educational objective is to engage graduate and undergraduate students in critical roles in the design, development, test, carrier integration and on-orbit operations of CASTOR as a supplement to their curricular activities. This program is laying the foundation for a long-term satellite construction program at MIT. The satellite is being designed as a part of AFRL's University Nanosatellite Program, which provides the funding and a framework in which student satellite teams compete for a launch to orbit. To this end, the satellite must fit within an envelope of 50cmx50cmx60cm, have a mass of less than 50kg, and meet stringent structural and other requirements. In this framework, the CASTOR team successfully completed PDR in August 2009 and CDR in April 2010 and will compete at FCR (Flight Competition Review) in January 2011. The complexity of the project requires implementation of many systems engineering techniques which allow for development of CASTOR from conception through FCR and encompass the full design, fabrication, and testing process.

  8. Cloud Point Extraction for Electroanalysis: Anodic Stripping Voltammetry of Cadmium.

    Science.gov (United States)

    Rusinek, Cory A; Bange, Adam; Papautsky, Ian; Heineman, William R

    2015-06-16

    Cloud point extraction (CPE) is a well-established technique for the preconcentration of hydrophobic species from water without the use of organic solvents. Subsequent analysis is then typically performed via atomic absorption spectroscopy (AAS), UV-vis spectroscopy, or high performance liquid chromatography (HPLC). However, the suitability of CPE for electroanalytical methods such as stripping voltammetry has not been reported. We demonstrate the use of CPE for electroanalysis using the determination of cadmium (Cd(2+)) by anodic stripping voltammetry (ASV). Rather than using the chelating agents which are commonly used in CPE to form a hydrophobic, extractable metal complex, we used iodide and sulfuric acid to neutralize the charge on Cd(2+) to form an extractable ion pair. This offers good selectivity for Cd(2+) as no interferences were observed from other heavy metal ions. Triton X-114 was chosen as the surfactant for the extraction because its cloud point temperature is near room temperature (22-25 °C). Bare glassy carbon (GC), bismuth-coated glassy carbon (Bi-GC), and mercury-coated glassy carbon (Hg-GC) electrodes were compared for the CPE-ASV. A detection limit for Cd(2+) of 1.7 nM (0.2 ppb) was obtained with the Hg-GC electrode. ASV with CPE gave a 20x decrease (4.0 ppb) in the detection limit compared to ASV without CPE. The suitability of this procedure for the analysis of tap and river water samples was demonstrated. This simple, versatile, environmentally friendly, and cost-effective extraction method is potentially applicable to a wide variety of transition metals and organic compounds that are amenable to detection by electroanalytical methods.

  9. Impedance Analysis of Silicon Nanowire Lithium Ion Battery Anodes

    KAUST Repository

    Ruffo, Riccardo

    2009-07-02

    The impedance behavior of silicon nanowire electrodes has been investigated to understand the electrochemical process kinetics that influences the performance when used as a high-capacity anode in a lithium ion battery. The ac response was measured by using impedance spectroscopy in equilibrium conditions at different lithium compositions and during several cycles of charge and discharge in a half cell vs. metallic lithium. The impedance analysis shows the contribution of both surface resistance and solid state diffusion through the bulk of the nanowires. The surface process is dominated by a solid electrolyte layer (SEI) consisting of an inner, inorganic insoluble part and several organic compounds at the outer interface, as seen by XPS analysis. The surface resistivity, which seems to be correlated with the Coulombic efficiency of the electrode, grows at very high lithium contents due to an increase in the inorganic SEI thickness. We estimate the diffusion coefficient of about 2 × 10 -10 cm 2/s for lithium diffusion in silicon. A large increase in the electrode impedance was observed at very low lithium compositions, probably due to a different mechanism for lithium diffusion inside the wires. Restricting the discharge voltage to 0.7 V prevents this large impedance and improves the electrode lifetime. Cells cycled between 0.07 and 0.70 V vs. metallic lithium at a current density of 0.84 A/g (C/5) showed good Coulombic efficiency (about 99%) and maintained a capacity of about 2000 mAh/g after 80 cycles. © 2009 American Chemical Society.

  10. Electrocatalysis of anodic and cathodic oxygen-transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wels, B.R.

    1990-09-21

    The electrocatalysis of oxygen-transfer reactions is discussed in two parts. In Part I, the reduction of iodate (IO{sub 3}{sup {minus}}) is examined as an example of cathodic oxygen transfer. On oxide-covered Pt electrodes (PtO), a large cathodic current is observed in the presence of IO{sub 3}{sup {minus}} to coincide with the reduction of PtO. The total cathodic charge exceeds the amount required for reduction of PtO and IO{sub 3}{sup {minus}} to produce an adsorbed product. An electrocatalytic link between reduction of IO{sub 3}{sup {minus}} and reduction of PtO is indicated. In addition, on oxide-free Pt electrodes, the reduction of IO{sub 3}{sup {minus}} is determined to be sensitive to surface treatment. The electrocatalytic oxidation of CN{sup {minus}} is presented as an example of anodic oxygen transfer in Part II. The voltametric response of CN{sup {minus}} is virtually nonexistent at PbO{sub 2} electrodes. The response is significantly improved by doping PbO{sub 2} with Cu. Cyanide is also oxidized effectively at CuO-film electrodes. Copper is concluded to serve as an adsorption site for CN{sup {minus}}. It is proposed that an oxygen tunneling mechanism comparable to electron tunneling does not occur at the electrode-solution interface. The adsorption of CN{sup {minus}} is therefore considered to be a necessary prerequisite for oxygen transfer. 201 refs., 23 figs., 2 tabs.

  11. Influence of Mn2+ ions on the corrosion mechanism of lead-based anodes and the generation of heavy metal anode slime in zinc sulfate electrolyte.

    Science.gov (United States)

    Zhang, Chenmu; Duan, Ning; Jiang, Linhua; Xu, Fuyuan; Luo, Jin

    2018-02-15

    The influence of Mn 2+ ions on the generation of heavy metal anode slime during zinc electrolysis industry was extensively investigated using several electrochemical methods, electron microscope technologies, and particle size analysis. Results showed that the Mn 2+ could obviously promote oxygen evolution reaction (OER) and thereby weaken oxidation efficiency of Mn 2+ (η MnO2 ) and dissolution of Pb 2+ . The significant improvement in kinetic parameters for OER was found in electrolytes of 1 and 3 g/L Mn 2+ , but became unstable as the Mn 2+ concentration increased to 10 g/L. This result was correlated with much different properties of oxide layers that its changes of microstructure are involved in, since it confirmed that the positive role of compact oxide layers in contributing to high corrosion resistance and activity for OER, but excessive Mn 2+ , resulted in its micromorphology of overthickness and instability. Such differences resulted from the effect of the Mn 2+ concentration fluctuation on kinetic rates of the nucleation growth process. The formation and adsorption of intermediate MnO 2 -OH ads identified as the controlled step for Mn 2+ catalyzing OER was also recommended. The generation mechanism of anode slime was found to be changed in essence due to varying Mn 2+ concentrations. In electrolyte of 1 g/L Mn 2+ , results revealed that the root cause of excessive small suspended anode slime (around 20 μm) was the change of the initial pathway of Mn 2+ electro-oxidation, whereas, it showed great improvement in the settling performance as the Mn 2+ concentration was increased to 10 g/L. Considering the potential of optimizing Mn 2+ concentrations as a cleaner approach to control anode slime, deepening the understanding of the impact mechanism of Mn 2+ can provide new insights into intervention in the generation of anode slime.

  12. Increased Power in Sediment Microbial Fuel Cell: Facilitated Mass Transfer via a Water-Layer Anode Embedded in Sediment

    OpenAIRE

    Lee, Yoo Seok; An, Junyeong; Kim, Bongkyu; Park, HyunJun; Kim, Jisu; Chang, In Seop

    2015-01-01

    We report a methodology for enhancing the mass transfer at the anode electrode of sediment microbial fuel cells (SMFCs), by employing a fabric baffle to create a separate water-layer for installing the anode electrode in sediment. The maximum power in an SMFC with the anode installed in the separate water-layer (SMFC-wFB) was improved by factor of 6.6 compared to an SMFC having the anode embedded in the sediment (SMFC-woFB). The maximum current density in the SMFC-wFB was also 3.9 times highe...

  13. Effect of conductive polymers coated anode on the performance of microbial fuel cells (MFCs) and its biodiversity analysis.

    Science.gov (United States)

    Li, Chao; Zhang, Libin; Ding, Lili; Ren, Hongqiang; Cui, Hao

    2011-06-15

    Conductive polymer, one of the most attractive electrode materials, has been applied to coat anode of MFC to improve its performance recently. In this paper, two conductive polymer materials, polyaniline (PANI) and poly(aniline-co-o-aminophenol) (PAOA) were used to modify carbon felt anode and physical and chemical properties of the modified anodes were studied. The power output and biodiversity of modified anodes, along with unmodified carbon anode were compared in two-chamber MFCs. Results showed that the maximum power density of PANI and PAOA MFC could reach 27.4 mW/m(2) and 23.8 mW/m(2), comparing with unmodified MFC, increased by 35% and 18% separately. Low temperature caused greatly decrease of the maximum voltage by 70% and reduced the sorts of bacteria on anodes in the three MFCs. Anode biofilm analysis showed different bacteria enrichment: a larger mount of bacteria and higher biodiversity were found on the two modified anodes than on the unmodified one. For PANI anode, the two predominant bacteria were phylogenetically closely related to Hippea maritima and an uncultured clone MEC_Bicarb_Ac-008; for PAOA, Clostridiales showed more enrichment. Compare PAOA with PANI, the former introduced phenolic hydroxyl group by copolymerization o-aminophenol with aniline, which led to a different microbial community and the mechanism of group effect was proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Single-step direct fabrication of pillar-on-pore hybrid nanostructures in anodizing aluminum for superior superhydrophobic efficiency.

    Science.gov (United States)

    Jeong, Chanyoung; Choi, Chang-Hwan

    2012-02-01

    Conventional electrochemical anodizing processes of metals such as aluminum typically produce planar and homogeneous nanopore structures. If hydrophobically treated, such 2D planar and interconnected pore structures typically result in lower contact angle and larger contact angle hysteresis than 3D disconnected pillar structures and, hence, exhibit inferior superhydrophobic efficiency. In this study, we demonstrate for the first time that the anodizing parameters can be engineered to design novel pillar-on-pore (POP) hybrid nanostructures directly in a simple one-step fabrication process so that superior surface superhydrophobicity can also be realized effectively from the electrochemical anodization process. On the basis of the characteristic of forming a self-ordered porous morphology in a hexagonal array, the modulation of anodizing voltage and duration enabled the formulation of the hybrid-type nanostructures having controlled pillar morphology on top of a porous layer in both mild and hard anodization modes. The hybrid nanostructures of the anodized metal oxide layer initially enhanced the surface hydrophilicity significantly (i.e., superhydrophilic). However, after a hydrophobic monolayer coating, such hybrid nanostructures then showed superior superhydrophobic nonwetting properties not attainable by the plain nanoporous surfaces produced by conventional anodization conditions. The well-regulated anodization process suggests that electrochemical anodizing can expand its usefulness and efficacy to render various metallic substrates with great superhydrophilicity or -hydrophobicity by directly realizing pillar-like structures on top of a self-ordered nanoporous array through a simple one-step fabrication procedure.

  15. Performance of two different types of anodes in membrane electrode assembly microbial fuel cells for power generation from domestic wastewater

    KAUST Repository

    Hays, Sarah

    2011-10-01

    Graphite fiber brush electrodes provide high surface areas for exoelectrogenic bacteria in microbial fuel cells (MFCs), but the cylindrical brush format limits more compact reactor designs. To enable MFC designs with closer electrode spacing, brush anodes were pressed up against a separator (placed between the electrodes) to reduce the volume occupied by the brush. Higher maximum voltages were produced using domestic wastewater (COD = 390 ± 89 mg L-1) with brush anodes (360 ± 63 mV, 1000 Ω) than woven carbon mesh anodes (200 ± 81 mV) with one or two separators. Maximum power densities were similar for brush anode reactors with one or two separators after 30 days (220 ± 1.2 and 240 ± 22 mW m-2), but with one separator the brush anode MFC power decreased to 130 ± 55 mW m-2 after 114 days. Power densities in MFCs with mesh anodes were very low (<45 mW m-2). Brush anodes MFCs had higher COD removals (80 ± 3%) than carbon mesh MFCs (58 ± 7%), but similar Coulombic efficiencies (8.6 ± 2.9% brush; 7.8 ± 7.1% mesh). These results show that compact (hemispherical) brush anodes can produce higher power and more effective domestic wastewater treatment than flat mesh anodes in MFCs. © 2011 Elsevier B.V. All rights reserved.

  16. Molecular dynamics simulations of the first charge of a Li-ion-Si-anode nanobattery.

    Science.gov (United States)

    Galvez-Aranda, Diego E; Ponce, Victor; Seminario, Jorge M

    2017-04-01

    Rechargeable lithium-ion batteries are the most popular devices for energy storage but still a lot of research needs to be done to improve their cycling and storage capacity. Silicon has been proposed as an anode material because of its large theoretical capacity of ∼3600 mAh/g. Therefore, focus is needed on the lithiation process of silicon anodes where it is known that the anode increases its volume more than 300%, producing cracking and other damages. We performed molecular dynamics atomistic simulations to study the swelling, alloying, and amorphization of a silicon nanocrystal anode in a full nanobattery model during the first charging cycle. A dissolved salt of lithium hexafluorophosphate in ethylene carbonate was chosen as the electrolyte solution and lithium cobalt oxide as cathode. External electric fields are applied to emulate the charging, causing the migration of the Li-ions from the cathode to the anode, by drifting through the electrolyte solution, thus converting pristine Si gradually into Li 14 Si 5 when fully lithiated. When the electric field is applied to the nanobattery, the temperature never exceeds 360 K due to a temperature control imposed resembling a cooling mechanism. The volume of the anode increases with the amorphization of the silicon as the external field is applied by creating a layer of LiSi alloy between the electrolyte and the silicon nanocrystal and then, at the arrival of more Li-ions changing to an alloy, where the drift velocity of Li-ions is greater than the velocity in the initial nanocrystal structure. Charge neutrality is maintained by concerted complementary reduction-oxidation reactions at the anode and cathode, respectively. In addition, the nanobattery model developed here can be used to study charge mobility, current density, conductance and resistivity, among several other properties of several candidate materials for rechargeable batteries and constitutes the initial point for further studies on the formation of

  17. Phase III Advanced Anodes and Cathodes Utilized in Energy Efficient Aluminum Production Cells

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Christini; R.K. Dawless; S.P. Ray; D.A. Weirauch, Jr.

    2001-11-05

    During Phase I of the present program, Alcoa developed a commercial cell concept that has been estimated to save 30% of the energy required for aluminum smelting. Phase ii involved the construction of a pilot facility and operation of two pilots. Phase iii of the Advanced Anodes and Cathodes Program was aimed at bench experiments to permit the resolution of certain questions to be followed by three pilot cells. All of the milestones related to materials, in particular metal purity, were attained with distinct improvements over work in previous phases of the program. NiO additions to the ceramic phase and Ag additions to the Cu metal phase of the cermet improved corrosion resistance sufficiently that the bench scale pencil anodes met the purity milestones. Some excellent metal purity results have been obtained with anodes of the following composition: Further improvements in anode material composition appear to be dependent on a better understanding of oxide solubilities in molten cryolite. For that reason, work was commissioned with an outside consultant to model the MeO - cryolite systems. That work has led to a better understanding of which oxides can be used to substitute into the NiO-Fe2O3 ceramic phase to stabilize the ferrites and reduce their solubility in molten cryolite. An extensive number of vertical plate bench electrolysis cells were run to try to find conditions where high current efficiencies could be attained. TiB2-G plates were very inconsistent and led to poor wetting and drainage. Pure TiB2 did produce good current efficiencies at small overlaps (shadowing) between the anodes and cathodes. This bench work with vertical plate anodes and cathodes reinforced the importance of good cathode wetting to attain high current efficiencies. Because of those conclusions, new wetting work was commissioned and became a major component of the research during the third year of Phase III. While significant progress was made in several areas, much work needs to be

  18. Anodic behavior of alloy 22 in bicarbonate containing media: Effect of alloying

    International Nuclear Information System (INIS)

    Zadorozne, N S; Giordano, C M; Rebak, R B; Ares, A E; Carranza, R M

    2012-01-01

    Alloy 22 is one of the candidates for the manufacture of high level nuclear waste containers. These containers provide services in natural environments characterized by multi-ionic solutions.It is estimated they could suffer three types of deterioration: general corrosion, localized corrosion (specifically crevice corrosion) and stress corrosion cracking (SCC). It has been confirmed that the presence of bicarbonate and chloride ions is necessary to produce cracking, . It has also been determined that the susceptibility to SCC could be related to the occurrence of an anodic peak in the polarization curves in these media at potentials below transpassivity. The aim of this work is to study the effect of alloying elements on the anodic behavior of Alloy 22 in media containing bicarbonate and chloride ions at different concentrations and temperatures. Polarization curves were made on alloy 22 (Ni-22% Cr-13% Mo), Ni-Mo (Ni-28, 5% Mo) and Ni-Cr (Ni-20% Cr) in the following solutions: 1 mol/L NaCl at 90 o C, and 1.148 mol/L NaHCO 3 ; 1.148 mol/L NaHCO 3 + 1 mol/L NaCl; 1.148 mol/L NaHCO 3 + 0.1 mol/L NaCl, at 90 o C, 75 o C, 60 o C and 25 o C. It was found that alloy 22 has a anodic current density peak at potentials below transpassivity, only in the presence of bicarbonate ions. Curves performed in 1 mol/L NaCl did not show any anodic peak, in any of the tested alloys. The curves made on alloys Ni-Mo and Ni-Cr in the presence of bicarbonate ions, allowed to determine that Cr, is responsible for the appearance of the anodic peak in alloy 22. The curves of alloy Ni-Mo showed no anodic peak in the studied conditions. The potential at which the anodic peak appears in alloy 22 and Ni-Cr alloy, increases with decreasing temperature. The anodic peak was also affected by solution composition. When chloride ion is added to bicarbonate solutions, the anodic peak is shifted to higher potential and current densities, depending on the concentration of added chloride ions (author)

  19. Aluminum anode for aluminum-air battery - Part II: Influence of In addition on the electrochemical characteristics of Al-Zn alloy in alkaline solution

    Science.gov (United States)

    Park, In-Jun; Choi, Seok-Ryul; Kim, Jung-Gu

    2017-07-01

    Effects of Zn and In additions on the aluminum anode for Al-air battery in alkaline solution are examined by the self-corrosion rate, cell voltage, current-voltage characteristics, anodic polarization, discharge performance and AC impedance measurements. The passivation behavior of Zn-added anode during anodic polarization decreases the discharge performance of Al-air battery. The addition of In to Al-Zn anode reduces the formation of Zn passivation film by repeated adsorption and desorption behavior of In ion onto anode surface. The attenuated Zn passive layer by In ion attack leads to the improvement of discharge performance of Al-air battery.

  20. Electrochemical performance and interfacial investigation on Si composite anode for lithium ion batteries in full cell

    Science.gov (United States)

    Shobukawa, Hitoshi; Alvarado, Judith; Yang, Yangyuchen; Meng, Ying Shirley

    2017-08-01

    Lithium ion batteries (LIBs) containing silicon (Si) as a negative electrode have gained much attention recently because they deliver high energy density. However, the commercialization of LIBs with Si anode is limited due to the unstable electrochemical performance associated with expansion and contraction during electrochemical cycling. This study investigates the electrochemical performance and degradation mechanism of a full cell containing Si composite anode and LiFePO4 (lithium iron phosphate (LFP)) cathode. Enhanced electrochemical cycling performance is observed when the full cell is cycled with fluoroethylene carbonate (FEC) additive compared to the standard electrolyte. To understand the improvement in the electrochemical performance, x-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) are used. Based on the electrochemical behavior, FEC improves the reversibility of lithium ion diffusion into the solid electrolyte interphase (SEI) on the Si composite anode. Moreover, XPS analysis demonstrates that the SEI composition generated from the addition of FEC consists of a large amount of LiF and less carbonate species, which leads to better capacity retention over 40 cycles. The effective SEI successively yields more stable capacity retention and enhances the reversibility of lithium ion diffusion through the interphase of the Si anode, even at higher discharge rate. This study contributes to a basic comprehension of electrochemical performance and SEI formation of LIB full cells with a high loading Si composite anode.

  1. Effect of aluminum anodizing in phosphoric acid electrolyte on adhesion strength and thermal performance

    Science.gov (United States)

    Lee, Sulki; Kim, Donghyun; Kim, Yonghwan; Jung, Uoochang; Chung, Wonsub

    2016-01-01

    This study examined the adhesive bond strength and thermal performance of the anodized aluminum 6061 in phosphoric acid electrolyte to improve the adhesive bond strength and thermal performance for use in metal core printed circuit boards (MCPCB). The electrolyte temperature and applied voltage were altered to generate varied pore structures. The thickness, porosity and pore diameter of the anodized layer were measured. The pore morphologies were affected most by temperature, which was the driving force for ion transportation. The mechanism of adhesive bond was penetration of the epoxy into the pores. The optimal anodization conditions for maximum adhesive bond strength, 27 MPa, were 293 K and 100V. The maximum thermal conductivity of the epoxy-treated anodized layer was 1.6 W/m·K at 273 K. Compared with the epoxy-treated Al layer used for conventional MCPCBs, the epoxy-treated anodized layer showed advanced thermal performance due to a low difference of thermal resistance and high heat dissipation.

  2. The impact of anode acclimation strategy on microbial electrolysis cell treating hydrogen fermentation effluent.

    Science.gov (United States)

    Li, Xiaohu; Zhang, Ruizhe; Qian, Yawei; Angelidaki, Irini; Zhang, Yifeng

    2017-07-01

    The impact of different anode acclimation methods for enhancing hydrogen production in microbial electrolysis cell (MEC) was investigated in this study. The anodes were first acclimated in microbial fuel cells using acetate, butyrate and corn stalk fermentation effluent (CSFE) as substrate before moving into MECs, respectively. Subsequently, CSFE was used as feedstock in all the three MECs. The maximum hydrogen yield with the anode pre-acclimated with butyrate (5.21±0.24L H 2 /L CSFE) was higher than that pre-acclimated with acetate (4.22±0.19L H 2 /L CSFE) and CSFE (4.55±0.14L H 2 /L CSFE). The current density (480±11A/m 3 ) and hydrogen production rate (4.52±0.13m 3 /m 3 /d) with the anode pre-acclimated with butyrate were also higher that another two reactors. These results demonstrated that the anode biofilm pre-acclimated with butyrate has significant advantages in CSFE treatment and could improve the performance of hydrogen production in MEC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Anode process on platinum in CaCl2-CaO-based melt

    Directory of Open Access Journals (Sweden)

    K. V. Tatarenko

    2014-12-01

    Full Text Available Methods potentiostatic polarization and cyclic voltammetry obtained new data on the mechanism and kinetics of anodic processes on platinum in the molten CaCl2-KCl-CaO when 725–775 °C. Given thermodynamic values of potential difference probable total reactions in the range of the studied temperature. Using potentiostatic polarization and cyclic voltammetry obtained new data on the mechanism and kinetics of anodic process on platinum in the molten CaCl2-KCl-CaO when 725–775 °C thermodynamic assessment of the probability of occurrence total reactions during electrolysis melt on the basis of CaCl2-CaO using non-carbon anode. It is shown that at high current densities anodic process takes place mainly in the conditions of slow diffusion of electrically active particles to the anode, and at low densities (up to 10 mA/cm2 to their discharge to the atomic and lecular oxygen is preceded by a stage, which can be associated with adsorption of atoms of oxygen or with the formation of an oxide film on the surface of platinum. To detect the nature of this stage, further research is needed.

  4. Nitrogen and europium doped TiO2 anodized films with applications in photocatalysis

    International Nuclear Information System (INIS)

    Chi, Choong-Soo; Choi, Jinwook; Jeong, Yongsoo; Lee, Oh Yeon; Oh, Han-Jun

    2011-01-01

    Micro-arc oxidation method is a useful process for mesoporous titanium dioxide films. In order to improve the photocatalytic activity of the TiO 2 film, N-Eu co-doped titania catalyst was synthesized by micro-arc oxidation in the H 2 SO 4 /Eu(NO 3 ) 3 mixture solution. The specific surface area and the roughness of the anodic titania film fabricated in the H 2 SO 4 /Eu(NO 3 ) 3 electrolyte, were increased compared to that of the anodic TiO 2 film prepared in H 2 SO 4 solution. The absorbance response of N-Eu titania film shows a higher adsorption onset toward visible light region, and the incorporated N and Eu ions during anodization as a dopant in the anodic TiO 2 film significantly enhanced the photocatalytic activity for dye degradation. After dye decomposition test for 3 h, dye removal rates for the anodic TiO 2 film were 60.7% and 90.1% for the N-Eu doped titania film. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the surface enlargement and the new electronic state of the TiO 2 band gap by N and Eu co-doping.

  5. Determination of the cathode and anode voltage drops in high power low-pressure amalgam lamps

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Vasiliev, A. I., E-mail: vasiliev@npo.lit.ru; Kostyuchenko, S. V.; Sokolov, D. V.; Startsev, A. Yu. [Joint Stock Company NPO LIT (Russian Federation); Kudryavtsev, N. N. [Moscow Institute of Physics and Technology (State University) (Russian Federation)

    2011-12-15

    For the first time, cathode and anode drops of powerful low-pressure amalgam lamps were measured. The lamp discharge current is 3.2 A, discharge current frequency is 43 kHz, linear electric power is 2.4 W/cm. The method of determination of a cathode drop is based on the change of a lamp operating voltage at variation of the electrode filament current at constant discharge current. The total (cathode plus anode) drop of voltage was measured by other, independent ways. The maximum cathode fall is 10.8 V; the anode fall corresponding to the maximal cathode fall is 2.4 V. It is shown that in powerful low pressure amalgam lamps the anode fall makes a considerable contribution (in certain cases, the basic one) to heating of electrodes. Therefore, the anode fall cannot be neglected, at design an electrode and ballast of amalgam lamps with operating discharge current frequency of tens of kHz.

  6. Determination of the cathode and anode voltage drops in high power low-pressure amalgam lamps

    International Nuclear Information System (INIS)

    Vasilyak, L. M.; Vasiliev, A. I.; Kostyuchenko, S. V.; Sokolov, D. V.; Startsev, A. Yu.; Kudryavtsev, N. N.

    2011-01-01

    For the first time, cathode and anode drops of powerful low-pressure amalgam lamps were measured. The lamp discharge current is 3.2 A, discharge current frequency is 43 kHz, linear electric power is 2.4 W/cm. The method of determination of a cathode drop is based on the change of a lamp operating voltage at variation of the electrode filament current at constant discharge current. The total (cathode plus anode) drop of voltage was measured by other, independent ways. The maximum cathode fall is 10.8 V; the anode fall corresponding to the maximal cathode fall is 2.4 V. It is shown that in powerful low pressure amalgam lamps the anode fall makes a considerable contribution (in certain cases, the basic one) to heating of electrodes. Therefore, the anode fall cannot be neglected, at design an electrode and ballast of amalgam lamps with operating discharge current frequency of tens of kHz.

  7. Synthesis and characterization of titania nanotubes by anodizing of titanium in fluoride containing electrolytes

    Science.gov (United States)

    Ahmad, Akhlaq; Haq, Ehsan Ul; Akhtar, Waseem; Arshad, Muhammad; Ahmad, Zubair

    2017-11-01

    Titania nanotubular structure was prepared by anodizing titanium metal in the fluoride containing electrolytes and studied for hydrogen reduction using photo electrochemical cell. Potentiodynamic scan was performed before actual anodizing to optimize the anodizing conditions. The morphology of the TiO2 nanotubes was investigated by SEM and the presence of TiO2 nanotubes was confirmed. Raman spectroscopy was done to confirm the different phases present. Hydrogen generation capability was revealed by electrochemical testing in three-electrode system in dark and in visible light at 200 W power using Gamry Potentiostat. The corrosion potential of TiO2 nanotubes produced was found to be more active side in potassium hydroxide solution under visible light than in the dark condition. Cathodic polarization behavior of specimens in the presence of light showed more activity towards hydrogen generation than in dark condition. In comparison, the hydrogen generation capability of specimen anodized in 2H15 electrolyte was higher than specimens anodized in other electrolytes. Electrochemical impedance spectroscopy was used to study the charge transfer resistance of the nanotubes produced. The results showed that TiO2 nanotubular structure is a promising material for photoelectrochemical cell. Low-charge transfer resistance also depicts that it can be efficiently used to harvest solar energy.

  8. Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control

    KAUST Repository

    Wu, Hui

    2012-03-25

    Although the performance of lithium ion-batteries continues to improve, their energy density and cycle life remain insufficient for applications in consumer electronics, transport and large-scale renewable energy storage 1-5. Silicon has a large charge storage capacity and this makes it an attractive anode material, but pulverization during cycling and an unstable solid-electrolyte interphase has limited the cycle life of silicon anodes to hundreds of cycles 6-11. Here, we show that anodes consisting of an active silicon nanotube surrounded by an ion-permeable silicon oxide shell can cycle over 6,000 times in half cells while retaining more than 85% of their initial capacity. The outer surface of the silicon nanotube is prevented from expansion by the oxide shell, and the expanding inner surface is not exposed to the electrolyte, resulting in a stable solid-electrolyte interphase. Batteries containing these double-walled silicon nanotube anodes exhibit charge capacities approximately eight times larger than conventional carbon anodes and charging rates of up to 20C (a rate of 1C corresponds to complete charge or discharge in one hour). © 2012 Macmillan Publishers Limited. All rights reserved.

  9. Effect of nitrogen addition on the performance of microbial fuel cell anodes

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Carbon cloth anodes were modified with 4(N,N-dimethylamino)benzene diazonium tetrafluoroborate to increase nitrogen-containing functional groups at the anode surface in order to test whether the performance of microbial fuel cells (MFCs) could be improved by controllably modifying the anode surface chemistry. Anodes with the lowest extent of functionalization, based on a nitrogen/carbon ratio of 0.7 as measured by XPS, achieved the highest power density of 938mW/m2. This power density was 24% greater than an untreated anode, and similar to that obtained with an ammonia gas treatment previously shown to increase power. Increasing the nitrogen/carbon ratio to 3.8, however, decreased the power density to 707mW/m2. These results demonstrate that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to the surface. © 2010 Elsevier Ltd.

  10. Anomalous acceleration of ions in a plasma accelerator with an anodic layer

    Science.gov (United States)

    V, M. BARDAKOV; S, D. IVANOV; A, V. KAZANTSEV; N, A. STROKIN; A, N. STUPIN; Binhao, JIANG; Zhenyu, WANG

    2018-03-01

    In a plasma accelerator with an anodic layer (PAAL), we discovered experimentally the effect of ‘super-acceleration’ of the bulk of the ions to energies W exceeding the energy equivalent to the discharge voltage V d. The E × B discharge was ignited in an environment of atomic argon and helium and molecular nitrogen. Singly charged argon ions were accelerated most effectively in the case of the largest discharge currents and pressure P of the working gas. Helium ions with W > eV d (e being the electron charge) were only recorded at maximum pressures. Molecular nitrogen was not accelerated to energies W > eV d. Anomalous acceleration is realized in the range of radial magnetic fields on the anode 2.8 × 10 -2 ≤ B rA ≤ 4 × 10 -2 T. It was also found analytically that the cathode of the accelerator can receive anomalously accelerated ions. In this case, the value of the potential in the anodic layer becomes higher than the anode potential, and the anode current exceeds some critical value. Numerical modeling in terms of the developed theory showed qualitative agreement between modeling data and measurements.

  11. Power output of microbial fuel cell emphasizing interaction of anodic binder with bacteria

    Science.gov (United States)

    Li, Hongying; Liao, Bo; Xiong, Juan; Zhou, Xingwang; Zhi, Huozhen; Liu, Xiang; Li, Xiaoping; Li, Weishan

    2018-03-01

    Electrochemically active biofilm is necessary for the electron transfer between bacteria and anodic electrode in microbial fuel cells and selecting the type of anodic electrode material that favours formation of electrochemically active biofilm is crucial for the microbial fuel cell operation. We report a new finding that the interaction of anodic binder with bacteria plays more important role than its hydrophilicity for forming an electrochemically active biofilm, which is emphasized by applying poly(bisphenol A-co-epichorohydrin) as an anodic binder of the microbial fuel cell based on carbon nanotubes as anodic electrode and Escherichia coli as bacterium. The physical characterizations and electrochemical measurements demonstrate that poly(bisphenol A-co-epichorohydrin) exhibits a strong interaction with bacteria and thus provides the microbial fuel cell with excellent power density output. The MFC using poly(bisphenol A-co-epichorohydrin) reaches a maximum power density output of 3.8 W m-2. This value is larger than that of the MFCs using polytetrafluoroethylene that has poorer hydrophilicity, or polyvinyl alcohol that has better hydrophilicity but exhibits weaker interaction with bacteria than poly(bisphenol A-co-epichorohydrin).

  12. Erosion craters on Ti{sub 3}SiC{sub 2} anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peng; Ngai, Tungwai Leo, E-mail: dhni@scut.edu.cn; Ding, Zhi; Li, Yuanyuan

    2014-06-27

    The erosion behavior of pure Ti{sub 3}SiC{sub 2} anode under vacuum discharge was investigated. By means of X-ray diffraction, energy dispersive spectroscopy and micro-Raman spectroscopy, the decomposition of Ti{sub 3}SiC{sub 2} into nonstoichiometric TiC{sub x}, amorphous carbon and other by-products was proved. The surface morphology was revealed by scanning electron microscope and 3D super depth digital microscope. Different kinds of craters with diameters varying from a few microns to a few hundred microns were observed on the anode surface after arcing. The smaller craters contain some TiC{sub x}, with a few tens of microns in diameter, are flower-like shaped with a protrusion pointing out from the center of the crater bottom. The larger craters are basically composed of TiC{sub x}, have diameters greater than one hundred microns but without the central protrusions, and are surrounded by collapse-fissures. - Highlights: • Ti{sub 3}SiC{sub 2} was proved to be decompose into TiC{sub x} under the influence of the vacuum arc. • The Si element in Ti{sub 3}SiC{sub 2} vaporized under the influence of the vacuum arc. • Footpoint mode craters and anode spot mode crater were observed on the anode surface. • The anode spot mode crater is basically composed of TiC{sub x}.

  13. Designable ultra-smooth ultra-thin solid-electrolyte interphases of three alkali metal anodes.

    Science.gov (United States)

    Gu, Yu; Wang, Wei-Wei; Li, Yi-Juan; Wu, Qi-Hui; Tang, Shuai; Yan, Jia-Wei; Zheng, Ming-Sen; Wu, De-Yin; Fan, Chun-Hai; Hu, Wei-Qiang; Chen, Zhao-Bin; Fang, Yuan; Zhang, Qing-Hong; Dong, Quan-Feng; Mao, Bing-Wei

    2018-04-09

    Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm -2 with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.

  14. Layer-by-layer graphene/TCNQ stacked films as conducting anodes for organic solar cells.

    Science.gov (United States)

    Hsu, Chang-Lung; Lin, Cheng-Te; Huang, Jen-Hsien; Chu, Chih-Wei; Wei, Kung-Hwa; Li, Lain-Jong

    2012-06-26

    Large-area graphene grown by chemical vapor deposition (CVD) is a promising candidate for transparent conducting electrode applications in flexible optoelectronic devices such as light-emitting diodes or organic solar cells. However, the power conversion efficiency (PCE) of the polymer photovoltaic devices using a pristine CVD graphene anode is still not appealing due to its much lower conductivity than that of conventional indium tin oxide. We report a layer-by-layer molecular doping process on graphene for forming sandwiched graphene/tetracyanoquinodimethane (TCNQ)/graphene stacked films for polymer solar cell anodes, where the TCNQ molecules (as p-dopants) were securely embedded between two graphene layers. Poly(3-hexylthiophene)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM) bulk heterojunction polymer solar cells based on these multilayered graphene/TCNQ anodes are fabricated and characterized. The P3HT/PCBM device with an anode structure composed of two TCNQ layers sandwiched by three CVD graphene layers shows optimum PCE (∼2.58%), which makes the proposed anode film quite attractive for next-generation flexible devices demanding high conductivity and transparency.

  15. In situ formation of graphene layers on graphite surfaces for efficient anodes of microbial fuel cells.

    Science.gov (United States)

    Tang, Jiahuan; Chen, Shanshan; Yuan, Yong; Cai, Xixi; Zhou, Shungui

    2015-09-15

    Graphene can be used to improve the performance of the anode in a microbial fuel cell (MFC) due to its good biocompatibility, high electrical conductivity and large surface area. However, the chemical production and modification of the graphene on the anode are environmentally hazardous because of the use of various harmful chemicals. This study reports a novel method based on the electrochemical exfoliation of a graphite plate (GP) for the in situ formation of graphene layers on the surface of a graphite electrode. When the resultant graphene-layer-based graphite plate electrode (GL/GP) was used as an anode in an MFC, a maximum power density of 0.67 ± 0.034 W/m(2) was achieved. This value corresponds to 1.72-, 1.56- and 1.26-times the maximum power densities of the original GP, exfoliated-graphene-modified GP (EG/GP) and chemically-reduced-graphene-modified GP (rGO/GP) anodes, respectively. Electrochemical measurements revealed that the high performance of the GL/GP anode was attributable to its macroporous structure, improved electron transfer and high electrochemical capacitance. The results demonstrated that the proposed method is a facile and environmentally friendly synthesis technique for the fabrication of high-performance graphene-based electrodes for use in microbial energy harvesting. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Synthesis of aluminum oxy-hydroxide nanofibers from porous anodic alumina

    International Nuclear Information System (INIS)

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2008-01-01

    A novel method for the synthesis of aluminum oxy-hydroxide nanofibers from a porous anodic oxide film of aluminum is demonstrated. In the present method, the porous anodic alumina not only acts as a template, but also serves as the starting material for the synthesis. The porous anodic alumina film is hydrothermally treated for pore-sealing, which forms aluminum oxy-hydroxide inside the pores of the oxide film as well as on the surface of the film. The hydrothermally sealed porous oxide film is immersed in the sodium citrate solution, which selectively etches the porous aluminum oxide from the film, leaving the oxy-hydroxide intact. The method is simple and gives highly uniform aluminum oxy-hydroxide nanofibers. Moreover, the diameter of the nanofibers can be controlled by controlling the pore size of the porous anodic alumina film, which depends on the anodizing conditions. Nanofibers with diameters of about 38-85 nm, having uniform shape and size, were successfully synthesized using the present method

  17. Effect of interlayer on structure and performance of anode-supported SOFC single cells

    International Nuclear Information System (INIS)

    Eom, Tae Wook; Yang, Hae Kwang; Kim, Kyung Hwan; Yoon, Hyon Hee; Kim, Jong Sung; Park, Sang Joon

    2008-01-01

    To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57 W/cm 2 at 800 deg. C and 0.44 W/cm 2 at 700 deg. C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer

  18. Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva

    Energy Technology Data Exchange (ETDEWEB)

    Romonti, Daniela E. [Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, district 1, Bucharest Ro-011061 (Romania); Gomez Sanchez, Andrea V. [INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo, 4302, B7608FDQ Mar del Plata (Argentina); Milošev, Ingrid [Jožef Stefan Institute, Department of Physical and Organic Chemistry, Jamova c. 39, SI-1000 Ljubljana (Slovenia); Demetrescu, Ioana [Faculty of Applied Chemistry and Materials Science, Department of General Chemistry, 1-7 Polizu, district 1, Bucharest Ro-011061 (Romania); Ceré, Silvia, E-mail: smcere@fi.mdp.edu.ar [INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo, 4302, B7608FDQ Mar del Plata (Argentina)

    2016-05-01

    The paper is focused on elaboration of ZrO{sub 2} films on pure zirconium via anodizing in phosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. The structure and composition of the films were investigated using scanning electronic microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition of the oxides formed at both potentials can be identified as monoclinic ZrO{sub 2.} In addition to Zr and O, the layers formed in phosphoric acid contain phosphorus originating from the phosphoric acid. When the phosphoric acid solution contains NaF, fluorine is also incorporated into the oxide layer. The oxides formed at a higher voltage have greater roughness than those formed at 30 V. Anodized samples exhibit smaller current densities during anodic polarization compared to the as-received zirconium covered with native oxide. - Highlights: • Anodic oxide layer formed on Zr in phosphoric acid with fluoride is monoclinic ZrO{sub 2}. • Fluorine ions from the electrolyte are incorporated in the oxide layer. • Anodic polarization in Afnor solution evidences breakdown of the passive films. • Decrease of breakdown potential may be induced by defects caused by fluorine.

  19. In situ fabrication of green reduced graphene-based biocompatible anode for efficient energy recycle.

    Science.gov (United States)

    Cheng, Ying; Mallavarapu, Megharaj; Naidu, Ravi; Chen, Zuliang

    2018-02-01

    Improving the anode configuration to enhance biocompatibility and accelerate electron shuttling is critical for efficient energy recovery in microbial fuel cells (MFCs). In this paper, green reduced graphene nanocomposite was successfully coated using layer-by-layer assembly technique onto carbon brush anode. The modified anode achieved a 3.2-fold higher power density of 33.7 W m -3 at a current density of 69.4 A m -3 with a 75% shorter start period. As revealed in the characterization, the green synthesized nanocomposite film affords larger surface roughness for microbial colonization. Besides, gold nanoparticles, which anchored on graphene sheets, promise the relatively high electroactive sites and facilitate electron transfer from electricigens to the anode. The reduction-oxidation peaks in cyclic voltammograms indicated the mechanism of surface cytochromes facilitated current generation while the electrochemical impedance spectroscopy confirmed the enhanced electron transfer from surface cytochrome to electrode. The green synthesis process has the potential to generate a high performing anode in further applications of MFCs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Paradox phenomena of proton exchange membrane fuel cells operating under dead-end anode mode

    Science.gov (United States)

    Jiang, Dong; Zeng, Rong; Wang, Shumao; Jiang, Lijun; Varcoe, John R.

    2014-11-01

    By using two spatially separated reference electrodes in a single cell proton-exchange membrane fuel cell (PEMFC), the individual potentials of the anode and cathode are recorded under realistic operating conditions. The PEMFC is operated under dead-end anode (DEA) mode, without any humidification, to mitigate water accumulation at the anode. Although N2 crossover from cathode to anode may play an important role in PEMFCs operating under DEA mode, our results unexpectedly show that the over-potentials of both the anode and cathode concomitantly increased or decreased at the same time. The increases of over-potentials correlate to the increase of the high frequency resistance of the cell (Rhf) imply that the water content in the membrane electrode assemblies is critical. However, the subsequent H2 depletion tests suggest that water may accumulate at the interface between the surface of the catalyst and the ultrathin perfluorosulfonic acid (PFSA) ionomer film and this contradicts the above (the increase in Rhf implies the drying out of the MEAs). This study highlights the need for further research into understanding the water transport properties of the ultrathin PFSA ionomer film (<60 nm): it is clear that these exhibit completely different properties to that of bulk proton-exchange membranes (PEM).

  1. Effect of temperature on the anodizing process of aluminum alloy AA 5052

    Science.gov (United States)

    Theohari, S.; Kontogeorgou, Ch.

    2013-11-01

    The effect of temperature (10-40 °C) during the anodizing process of AA 5052 for 40 min in 175 g/L sulfuric acid solution at constant voltage (15 V) was studied in comparison with pure aluminum. The incorporated magnesium species in the barrier layer result in the further increase of the minimum current density passed during anodizing, as the temperature increases, by about 42% up to 30 °C and then by 12% up to 40 °C. Then during the anodizing process for 40 min a blocking effect on oxide film growth was gradually observed as the temperature increased until 30 °C. The results of EDAX analysis on thick films reveal that the mean amount of the magnesium species inside the film is about 50-70% less than that in the bulk alloy, while it is higher at certain locations adjacent to the film surface at 30 °C. The increase of anodizing temperature does not influence the porosity of thin films (formed for short times) on pure aluminum, while it reduces it on the alloy. At 40 °C the above mentioned blocking effects disappear. It means that the presence of magnesium species causes an impediment to the effect of temperature on iss, on the film thickness and on the porosity of thin films, only under conditions where film growth takes place without significant loss of the anodizing charge to side reactions.

  2. Fabrication of the micro/nano-structure superhydrophobic surface on aluminum alloy by sulfuric acid anodizing and polypropylene coating.

    Science.gov (United States)

    Wu, Ruomei; Liang, Shuquan; Liu, Jun; Pan, Anqiang; Yu, Y; Tang, Yan

    2013-03-01

    The preparation of the superhydrophobic surface on aluminum alloy by anodizing and polypropylene (PP) coating was reported. Both the different anodizing process and different PP coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. By PP coating after anodizing, a good superhydrophobic surface was facilely fabricated. The optimum conditions for anodizing were determined by orthogonal experiments. After the aluminium-alloy was grinded with 600# sandpaper, pretreated by 73 g/L hydrochloric acid solution at 1 min, when the concentration of sulfuric acid was 180 g/L, the concentration of oxalic acid was 5 g/L, the concentration of potassium dichromate was 10 g/L, the concentration of chloride sodium was 50 g/L and 63 g/L of glycerol, anodization time was 20 min, and anodization current was 1.2 A/dm2, anodization temperature was 30-35 degrees C, the best micro-nanostructure aluminum alloy films was obtained. On the other hand, the PP with different concentrations was used to the PP with different concentrations was used to coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was achieved by coating PP, and the duration of the superhydrophobic surface was improved by modifying the coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was surface with high concentration PP. The morphologies of micro/nano-structure superhydrophobic surface were further confirmed by scanning electron microscope (SEM). The material of PP with the low surface free energy combined with the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  3. In situ X-ray diffraction studies of (de)lithiation mechanism in silicon nanowire anodes.

    Science.gov (United States)

    Misra, Sumohan; Liu, Nian; Nelson, Johanna; Hong, Seung Sae; Cui, Yi; Toney, Michael F

    2012-06-26

    Silicon is a promising anode material for Li-ion batteries due to its high theoretical specific capacity. From previous work, silicon nanowires (SiNWs) are known to undergo amorphorization during lithiation, and no crystalline Li-Si product has been observed. In this work, we use an X-ray transparent battery cell to perform in situ synchrotron X-ray diffraction on SiNWs in real time during electrochemical cycling. At deep lithiation voltages the known metastable Li(15)Si(4) phase forms, and we show that avoiding the formation of this phase, by modifying the SiNW growth temperature, improves the cycling performance of SiNW anodes. Our results provide insight on the (de)lithiation mechanism and a correlation between phase evolution and electrochemical performance for SiNW anodes.

  4. Composite Li metal anode with vertical graphene host for high performance Li-S batteries

    Science.gov (United States)

    Zhang, Y. J.; Liu, S. F.; Wang, X. L.; Zhong, Y.; Xia, X. H.; Wu, J. B.; Tu, J. P.

    2018-01-01

    Efficient and stable operation of a lithium metal anode has become the enabling factor for next-generation high energy density storage system. Here, vertical graphene (VG) arrays are used as the scaffold structure for high performance Li metal batteries. The melt infusion method is employed to encapsulate Li inside the VG scaffold structure, and the lithiophilic Si layer is coated onto the array surface by magnetron sputtering to assist this melt-infusion process. The porous scaffold structure can control the volume expansion and inhibit the formation of dendritic lithium significantly, leading to the excellent electrochemical performance of the Li composite anode. In addition, the Li-S full batteries with the composite anode display enhanced cycling reversibility.

  5. Method for providing uranium articles with a corrosion-resistant anodized coating

    Science.gov (United States)

    Waldrop, F.B.; Washington, C.A.

    1981-01-07

    Uranium articles are provided with anodized oxide coatings in an aqueous solution of an electrolyte selected from the group consisting of potassium phosphate, potassium hydroxide, ammonium hydroxide, and a mixture of potassium tetraborate and boric acid. The uranium articles are anodized at a temperature greater than about 75/sup 0/C with a current flow of less than about 0.036 A/cm/sup 2/ of surface area while the pH of the solution is maintained in a range of about 2 to 11.5. The pH values of the aqueous solution and the low current density utilized during the electrolysis prevent excessive dissolution of the uranium and porosity in the film or watering. The relatively high temperature of the electrolyte bath inhibits hydration and the attendant deleterious pitting so as to enhance corrosion resistance of the anodized coating.

  6. Method for providing uranium articles with a corrosion resistant anodized coating

    Science.gov (United States)

    Waldrop, Forrest B.; Washington, Charles A.

    1982-01-01

    Uranium articles are provided with anodized oxide coatings in an aqueous solution of an electrolyte selected from the group consisting of potassium phosphate, potassium hydroxide, ammonium hydroxide, and a mixture of potassium tetraborate and boric acid. The uranium articles are anodized at a temperature greater than about 75.degree. C. with a current flow of less than about 0.036 A/cm.sup.2 of surface area while the pH of the solution is maintained in a range of about 2 to 11.5. The pH values of the aqueous solution and the low current density utilized during the electrolysis prevent excessive dissolution of the uranium and porosity in the film or watering. The relatively high temperature of the electrolyte bath inhibits hydration and the attendant deleterious pitting so as to enhance corrosion resistance of the anodized coating.

  7. Liquid-metal-jet anode electron-impact x-ray source

    International Nuclear Information System (INIS)

    Hemberg, O.; Otendal, M.; Hertz, H.M.

    2003-01-01

    We demonstrate an anode concept, based on a liquid-metal jet, for improved brightness in compact electron-impact x-ray sources. The source is demonstrated in a proof-of-principle experiment where a 50 keV, ∼100 W electron beam is focused on a 75 μm liquid-solder jet. The generated x-ray flux and brightness is quantitatively measured in the 7-50 keV spectral region and found to agree with theory. Compared to rotating-anode sources, whose brightness is limited by intrinsic thermal properties, the liquid-jet anode could potentially be scaled to achieve a brightness >100x higher than current state-of-the-art sources. Applications such as mammography, angiography, and diffraction would benefit from such a compact high-brightness source

  8. Proportional counters aged anode wire recovering using an 80%CF4 + 20%CO2 gas mixture

    CERN Document Server

    Gavrilov, Gennady; Conti, Richard; Fetisov, Andrey; Maysuzenko, Dmitry; Shvecova, Natalia; Vakhtel, Victor

    2011-01-01

    A technique to recover a gas proportional counter having an aged anode wire using a glow discharge in an 80%CF4 + 20%CO2 gas mixture has been developed and tested. Studies of aging effects were carried out under sustained irradiation by an intense 90Sr -source of the straw proportional counters operated with a 60%Ar + 30%CO2 + 10%CF4 gas mixture. Special attention was paid to the aging mechanism of the anode wires. Our experience showed that using a given gas mixture the swelling of the anode wires is a typical mode of aging that leads to degradation of the gas gain. The proposed method of recovery provided a complete restoration of the gas gain and the signal amplitude in the damaged zone of the wire. SEM/XEM analysis confirmed successful cleaning WOx deposits from the wire surface. The application of this method to recover the aged gaseous detectors in real experimental conditions is discussed.

  9. Organic photovoltaics using thin gold film as an alternative anode to indium tin oxide

    International Nuclear Information System (INIS)

    Haldar, Amrita; Yambem, Soniya D.; Liao, Kang-Shyang; Alley, Nigel J.; Dillon, Eoghan P.; Barron, Andrew R.; Curran, Seamus A.

    2011-01-01

    Indium Tin Oxide (ITO) is the most commonly used anode as a transparent electrode and more recently as an anode for organic photovoltaics (OPVs). However, there are significant drawbacks in using ITO which include high material costs, mechanical instability including brittleness and poor electrical properties which limit its use in low-cost flexible devices. We present initial results of poly(3-hexylthiophene): phenyl-C 61 -butyric acid methyl ester OPVs showing that an efficiency of 1.9% (short-circuit current 7.01 mA/cm 2 , open-circuit voltage 0.55 V, fill factor 0.49) can be attained using an ultra thin film of gold coated glass as the device anode. The initial I-V characteristics demonstrate that using high work function metals when the thin film is kept ultra thin can be used as a replacement to ITO due to their greater stability and better morphological control.

  10. Controlling Morphological Parameters of Anodized Titania Nanotubes for Optimized Solar Energy Applications

    Directory of Open Access Journals (Sweden)

    Michael Hu

    2012-10-01

    Full Text Available Anodized TiO2 nanotubes have received much attention for their use in solar energy applications including water oxidation cells and hybrid solar cells [dye-sensitized solar cells (DSSCs and bulk heterojuntion solar cells (BHJs]. High surface area allows for increased dye-adsorption and photon absorption. Titania nanotubes grown by anodization of titanium in fluoride-containing electrolytes are aligned perpendicular to the substrate surface, reducing the electron diffusion path to the external circuit in solar cells. The nanotube morphology can be optimized for the various applications by adjusting the anodization parameters but the optimum crystallinity of the nanotube arrays remains to be realized. In addition to morphology and crystallinity, the method of device fabrication significantly affects photon and electron dynamics and its energy conversion efficiency. This paper provides the state-of-the-art knowledge to achieve experimental tailoring of morphological parameters including nanotube diameter, length, wall thickness, array surface smoothness, and annealing of nanotube arrays.

  11. Nanostructured bilayer anodic TiO2/Al2O3 metal-insulator-metal capacitor.

    Science.gov (United States)

    Karthik, R; Kannadassan, D; Baghini, Maryam Shojaei; Mallick, P S

    2013-10-01

    This paper presents the fabrication of high performance bilayer TiO2/Al2O3 Metal-Insulator-Metal capacitor using anodization technique. A high capacitance density of 7 fF/microm2, low quadratic voltage coefficient of capacitance of 150 ppm/V2 and a low leakage current density of 9.1 nA/cm2 at 3 V are achieved which are suitable for Analog and Mixed signal applications. The influence of anodization voltage on structural and electrical properties of dielectric stack is studied in detail. At higher anodization voltages, we have observed the transformation of amorphous to crystalline state of TiO2/Al2O3 and improvement of electrical properties.

  12. Conversion Reaction-Based Oxide Nanomaterials for Lithium Ion Battery Anodes.

    Science.gov (United States)

    Yu, Seung-Ho; Lee, Soo Hong; Lee, Dong Jun; Sung, Yung-Eun; Hyeon, Taeghwan

    2016-04-27

    Developing high-energy-density electrodes for lithium ion batteries (LIBs) is of primary importance to meet the challenges in electronics and automobile industries in the near future. Conversion reaction-based transition metal oxides are attractive candidates for LIB anodes because of their high theoretical capacities. This review summarizes recent advances on the development of nanostructured transition metal oxides for use in lithium ion battery anodes based on conversion reactions. The oxide materials covered in this review include oxides of iron, manganese, cobalt, copper, nickel, molybdenum, zinc, ruthenium, chromium, and tungsten, and mixed metal oxides. Various kinds of nanostructured materials including nanowires, nanosheets, hollow structures, porous structures, and oxide/carbon nanocomposites are discussed in terms of their LIB anode applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Review of RedOx Cycling of Solid Oxide Fuel Cells Anode

    Science.gov (United States)

    Faes, Antonin; Hessler-Wyser, Aïcha; Zryd, Amédée; Van Herle, Jan

    2012-01-01

    Solid oxide fuel cells are able to convert fuels, including hydrocarbons, to electricity with an unbeatable efficiency even for small systems. One of the main limitations for long-term utilization is the reduction-oxidation cycling (RedOx cycles) of the nickel-based anodes. This paper will review the effects and parameters influencing RedOx cycles of the Ni-ceramic anode. Second, solutions for RedOx instability are reviewed in the patent and open scientific literature. The solutions are described from the point of view of the system, stack design, cell design, new materials and microstructure optimization. Finally, a brief synthesis on RedOx cycling of Ni-based anode supports for standard and optimized microstructures is depicted. PMID:24958298

  14. Method for providing uranium articles with a corrosion resistant anodized coating

    International Nuclear Information System (INIS)

    Waldrop, F.B.; Washington, C.A.

    1982-01-01

    Uranium articles are provided with anodized oxide coatings in an aqueous solution of an electrolyte selected from the group consisting of potassium phosphate, potassium hydroxide, ammonium hydroxide, and a mixture of potassium tetraborate and boric acid. The uranium articles are anodized at a temperature greater than about 75 degrees C. With a current flow of less than about 0.036 A/cm2 of surface area while the Ph of the solution is maintained in a range of about 2 to 11.5. The Ph values of the aqueous solution and the low current density utilized during the electrolysis prevent excessive dissolution of the uranium and porosity in the film or watering. The relatively high temperature of the electrolyte bath inhibits hydration and the attendant deleterious pitting so as to enhance corrosion resistance of the anodized coating

  15. Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals.

    Science.gov (United States)

    Santos, Abel; Law, Cheryl Suwen; Pereira, Taj; Losic, Dusan

    2016-04-21

    Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information.

  16. Phosphorus-doped silicon nanorod anodes for high power lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Chao Yan

    2017-01-01

    Full Text Available Heavy-phosphorus-doped silicon anodes were fabricated on CuO nanorods for application in high power lithium-ion batteries. Since the conductivity of lithiated CuO is significantly better than that of CuO, after the first discharge, the voltage cut-off window was then set to the range covering only the discharge–charge range of Si. Thus, the CuO core was in situ lithiated and acts merely as the electronic conductor in the following cycles. The Si anode presented herein exhibited a capacity of 990 mAh/g at the rate of 9 A/g after 100 cycles. The anode also presented a stable rate performance even at a current density as high as 20 A/g.

  17. High pressure anode operation of direct methanol fuel cells for carbon dioxide management

    Science.gov (United States)

    Lundin, Michael D.; McCready, Mark J.

    Experiments with independent pressurization of the direct methanol fuel cell anode and cathode allow for the observation of DMFC operation with carbon dioxide gas formation suppressed. Results indicate that the limiting current density is strongly related to the applied pressure, and, therefore, to the presence of CO 2 in the liquid phase. An additional experiment where CO 2 is allowed to accumulate in recycled anode fuel solution over a period of time and is then stripped from solution using nitrogen gas indicates that the presence of CO 2 in anode fuel solution at any pressure contributes to significant decreases in power and current density. Because CO 2 bubbles are ubiquitous in direct methanol fuel cells, this finding is key to the optimization of these systems.

  18. Corrosion protection of iron using porous anodic oxide/conducting polymer composite coatings.

    Science.gov (United States)

    Konno, Yoshiki; Tsuji, Etsushi; Aoki, Yoshitaka; Ohtsuka, Toshiaki; Habazaki, Hiroki

    2015-01-01

    Conducting polymers (CPs), including polypyrrole, have attracted attention for their potential in the protection of metals against corrosion; however, CP coatings have the limitation of poor adhesion to metal substrates. In this study, a composite coating, comprising a self-organized porous anodic oxide layer and a polypyrrole layer, has been developed on iron. Because of electropolymerization in the pores of the anodic oxide layer, the composite coating showed improved adhesion to the substrate along with prolonged corrosion protection in a NaCl aqueous corrosive environment. The anodic oxide layers are formed in a fluoride-containing organic electrolyte and contain a large amount of fluoride species. The removal of these fluoride species from the oxide layer and the metal/oxide interface region is crucial for improving the corrosion protection.

  19. Gravure printed PEDOT:PSS as anode for flexible ITO-free organic light emitting diodes

    Directory of Open Access Journals (Sweden)

    M. Montanino

    2017-06-01

    Full Text Available Roll-to-roll gravure printing is considered as potential leading manufacturing technology for flexible, low cost and large area optoelectronics. However, solution processed multilayer organic electronics are still challenging to be produced, especially in the case of electrodes. In this work, the gravure printing technique was successfully employed to realize the highly conductive poly(3,4ethylenedioxythiophene:poly(styrene sulfonate (PEDOT:PSS polymeric anode and tested for the first time in flexible ITO-free (Indium Thin Oxide organic light emitting diodes (OLEDs. The device performances were found to be similar to those of a reference device containing a spin-coated polymeric anode. A gravure printed dimethyl sulfoxide (DMSO post-treatment was successfully tried to improve the printed anode characteristics. The obtained results show the way for future development for processing flexible ITO-free devices using the most attractive printing technology for roll-to-roll large area manufacturing.

  20. In Situ X-ray Diffraction Studies of (De)lithiation Mechanism in Silicon Nanowire Anodes

    KAUST Repository

    Misra, Sumohan

    2012-06-26

    Figure Persented: Silicon is a promising anode material for Li-ion batteries due to its high theoretical specific capacity. From previous work, silicon nanowires (SiNWs) are known to undergo amorphorization during lithiation, and no crystalline Li-Si product has been observed. In this work, we use an X-ray transparent battery cell to perform in situ synchrotron X-ray diffraction on SiNWs in real time during electrochemical cycling. At deep lithiation voltages the known metastable Li 15Si 4 phase forms, and we show that avoiding the formation of this phase, by modifying the SiNW growth temperature, improves the cycling performance of SiNW anodes. Our results provide insight on the (de)lithiation mechanism and a correlation between phase evolution and electrochemical performance for SiNW anodes. © 2012 American Chemical Society.