Molten salt applications in materials processing

NASA Astrophysics Data System (ADS)

Mishra, Brajendra; Olson, David L.

2005-02-01

The science of molten salt electrochemistry for electrowinning of reactive metals, such as calcium, and its in situ application in pyro-reduction has been described. Calcium electrowinning has been performed in a 5 10 wt% calcium oxide calcium chloride molten salt by the electrolytic dissociation of calcium oxide. This electrolysis requires the use of a porous ceramic sheath around the anode to keep the cathodically deposited calcium and the anodic gases separate. Stainless steel cathode and graphite anode have been used in the temperature range of 850 950 °C. This salt mixture is produced as a result of the direct oxide reduction (DOR) of reactive metal oxides by calcium in a calcium chloride bath. The primary purpose of this process is to recover the expensive calcium reductant and to recycle calcium chloride. Experimental data have been included to justify the suitability as well as limitations of the electrowinning process. Transport of oxygen ions through the sheath is found to be the rate controlling step. Under the constraints of the reactor design, a calcium recovery rate of approx. 150 g/h was achieved. Feasibility of a process to produce metals by pyrometallurgical reduction, using the calcium reductant produced electrolytically within the same reactor, has been shown in a hybrid process. Several processes are currently under investigation to use this electrowon calcium for in situ reduction of metal oxides.

CO2 decomposition using electrochemical process in molten salts

NASA Astrophysics Data System (ADS)

Otake, Koya; Kinoshita, Hiroshi; Kikuchi, Tatsuya; Suzuki, Ryosuke O.

2012-08-01

The electrochemical decomposition of CO2 gas to carbon and oxygen gas in LiCl-Li2O and CaCl2-CaO molten salts was studied. This process consists of electrochemical reduction of Li2O and CaO, as well as the thermal reduction of CO2 gas by the respective metallic Li and Ca. Two kinds of ZrO2 solid electrolytes were tested as an oxygen ion conductor, and the electrolytes removed oxygen ions from the molten salts to the outside of the reactor. After electrolysis in both salts, the aggregations of nanometer-scale amorphous carbon and rod-like graphite crystals were observed by transmission electron microscopy. When 9.7 %CO2-Ar mixed gas was blown into LiCl-Li2O and CaCl2-CaO molten salts, the current efficiency was evaluated to be 89.7 % and 78.5 %, respectively, by the exhaust gas analysis and the supplied charge. When a solid electrolyte with higher ionic conductivity was used, the current and carbon production became larger. It was found that the rate determining step is the diffusion of oxygen ions into the ZrO2 solid electrolyte.

Richland five-year O2 R and D Program. Integrated site operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1966-07-11

The technical feasibility of using an electrolytic reduction process to reduce metal scrap and oxide to usable uranium metal is being studied. The incentives for using electrolytic reduction at Richland may be summarized as follows: (1) reduce the unit and total costs of producing plutonium; (2) increase the flexibility of the Richland reactors for producing isotopes, particularly U-236; and (3) simplify the present fuel cycle complex. The scope of the mission is limited to the evaluation of hollow extruded I and E cores, the evaluation of electro-reduced uranium, an investigation of the solution rate of UO{sub 2} in the electrolyte,more » and small-scale irradiations of UO{sub 2} fuels in the N and K Reactors. Progress during FY 1966 is summarized.« less

Electrocatalysis of fuel cell reactions: Investigation of alternate electrolytes

NASA Technical Reports Server (NTRS)

Chin, D. T.; Hsueh, K. L.; Chang, H. H.

1984-01-01

Oxygen reduction and transport properties of the electrolyte in the phosphoric acid fuel cell are studied. The areas covered were: (1) development of a theoretical expression for the rotating ring disk electrode technique; (2) determination of the intermediate reaction rate constants for oxygen reduction on platinum in phosphoric acid electrolyte; (3) determination of oxygen reduction mechanism in trifluoreomethanesulfonic acid (TFMSA) which was considered as an alternate electrolyte for the acid fuel cells; and (4) the measurement of transport properties of the phosphoric acid electrolyte at high concentrations and temperatures.

Carbothermic Reduction of Nickeliferous Laterite Ores for Nickel Pig Iron Production in China: A Review

NASA Astrophysics Data System (ADS)

Rao, Mingjun; Li, Guanghui; Jiang, Tao; Luo, Jun; Zhang, Yuanbo; Fan, Xiaohui

2013-11-01

Both the consumption and production of crude stainless steel in China rank first in the world. In 2011, the nickel production in China amounted to 446 kilotons, with the proportion of electrolytic nickel and nickel pig iron (NPI) registering 41.5% and 56.5%, respectively. NPI is a low-cost feedstock for stainless steel production when used as a substitute for electrolytic nickel. The existing commercial NPI production processes such as blast furnace smelting, rotary kiln-electric furnace smelting, and Krupp-Renn (Nipon Yakin Oheyama) processes are discussed. As low-temperature (below 1300°C) reduction of nickeliferous laterite ores followed by magnetic separation could provide an alternative avenue without smelting at high temperature (~1500°C) for producing ferronickel with low cost, the fundamentals and recent developments of the low-temperature reduction of nickeliferous laterite ores are reviewed.

Magsonic™ Carbothermal Technology Compared with the Electrolytic and Pidgeon Processes

NASA Astrophysics Data System (ADS)

Prentice, Leon H.; Haque, Nawshad

A broad technology comparison of carbothermal magnesium production with present technologies has not been previously presented. In this paper a comparative analysis of CSIRO's MagSonic™ process is made with the electrolytic and Pidgeon processes. The comparison covers energy intensity (GJ/tonne Mg), labor intensity (person-hours/tonne Mg), capital intensity (USD/tonne annual Mg installed capacity), and Global Warming Potential (GWP, tonnes CO2-equivalent/tonne Mg). Carbothermal technology is advantageous on all measures except capital intensity (where it is roughly twice the capital cost of a similarly-sized Pidgeon plant). Carbothermal and electrolytic production can have comparatively low environmental impacts, with typical emissions one-sixth those of the Pidgeon process. Despite recent progress, the Pidgeon process depends upon abundant energy and labor combined with few environmental constraints. Pressure is expected to increase on environmental constraints and labor and energy costs over the coming decade. Carbothermal reduction technology appears to be competitive for future production.

Aluminum reference electrode

DOEpatents

Sadoway, D.R.

1988-08-16

A stable reference electrode is described for use in monitoring and controlling the process of electrolytic reduction of a metal. In the case of Hall cell reduction of aluminum, the reference electrode comprises a pool of molten aluminum and a solution of molten cryolite, Na[sub 3]AlF[sub 6], wherein the electrical connection to the molten aluminum does not contact the highly corrosive molten salt solution. This is accomplished by altering the density of either the aluminum (decreasing the density) or the electrolyte (increasing the density) so that the aluminum floats on top of the molten salt solution. 1 fig.

Reduced graphene oxide aerogel with high-rate supercapacitive performance in aqueous electrolytes

NASA Astrophysics Data System (ADS)

Si, Weijiang; Wu, Xiaozhong; Zhou, Jin; Guo, Feifei; Zhuo, Shuping; Cui, Hongyou; Xing, Wei

2013-05-01

Reduced graphene oxide aerogel (RGOA) is synthesized successfully through a simultaneous self-assembly and reduction process using hypophosphorous acid and I2 as reductant. Nitrogen sorption analysis shows that the Brunauer-Emmett-Teller surface area of RGOA could reach as high as 830 m2 g-1, which is the largest value ever reported for graphene-based aerogels obtained through the simultaneous self-assembly and reduction strategy. The as-prepared RGOA is characterized by a variety of means such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical tests show that RGOA exhibits a high-rate supercapacitive performance in aqueous electrolytes. The specific capacitance of RGOA is calculated to be 211.8 and 278.6 F g-1 in KOH and H2SO4 electrolytes, respectively. The perfect supercapacitive performance of RGOA is ascribed to its three-dimensional structure and the existence of oxygen-containing groups.

Reduced graphene oxide aerogel with high-rate supercapacitive performance in aqueous electrolytes.

PubMed

Si, Weijiang; Wu, Xiaozhong; Zhou, Jin; Guo, Feifei; Zhuo, Shuping; Cui, Hongyou; Xing, Wei

2013-05-21

Reduced graphene oxide aerogel (RGOA) is synthesized successfully through a simultaneous self-assembly and reduction process using hypophosphorous acid and I2 as reductant. Nitrogen sorption analysis shows that the Brunauer-Emmett-Teller surface area of RGOA could reach as high as 830 m2 g-1, which is the largest value ever reported for graphene-based aerogels obtained through the simultaneous self-assembly and reduction strategy. The as-prepared RGOA is characterized by a variety of means such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical tests show that RGOA exhibits a high-rate supercapacitive performance in aqueous electrolytes. The specific capacitance of RGOA is calculated to be 211.8 and 278.6 F g-1 in KOH and H2SO4 electrolytes, respectively. The perfect supercapacitive performance of RGOA is ascribed to its three-dimensional structure and the existence of oxygen-containing groups.

High-Energy-Density Electrolytic Capacitors

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping S.; Lewis, Carol R.

1993-01-01

Reductions in weight and volume make new application possible. Supercapacitors and improved ultracapacitors advanced electrolytic capacitors developed for use as electric-load-leveling devices in such applications as electric vehicle propulsion systems, portable power tools, and low-voltage pulsed power supplies. One primary advantage: offer power densities much higher than storage batteries. Capacitors used in pulse mode, with short charge and discharge times. Derived from commercially available ultracapacitors. Made of lightweight materials; incorporate electrode/electrolyte material systems capable of operation at voltages higher than previous electrode/electrolyte systems. By use of innovative designs and manufacturing processes, made in wide range of rated capacitances and in rated operating potentials ranging from few to several hundred volts.

Electrochemical reduction of (U-40Pu-5Np)O 2 in molten LiCl electrolyte

NASA Astrophysics Data System (ADS)

Iizuka, Masatoshi; Sakamura, Yoshiharu; Inoue, Tadashi

2006-12-01

The electrochemical reduction of neptunium-containing MOX ((U-40Pu-5Np)O 2) was performed in molten lithium chloride melt at 923 K to investigate fundamental behavior of the transuranium elements and applicability of the method to reduction process for these materials. The Np-MOX was electrochemically reduced at the potential lower than -0.6 V vs. Bi-35 mol% Li reference electrode. The reduced metal grains in the surface region of the sample cohered with each other and made the layer of relatively high density, although it did not prevent the reduction of the sample toward the center. Complete reduction of the Np-MOX was shown by the weight change measurement through the electrochemical reduction and also by SEM-EDX observation. The chemical composition of the reduction products was homogeneous and agreed to that of the initial Np-MOX, which indicates that the reduction was completed and not selective among the actinides. The concentrations of the actinide elements, especially plutonium and americium in the electrolyte, increased with the progress of the tests, although their absolute values were very small. It is quite likely that plutonium and americium dissolve into the melt in the same manner as the lanthanide elements in the lithium reduction process.

New electrolytes for aluminum production: Ionic liquids

NASA Astrophysics Data System (ADS)

Zhang, Mingming; Kamavarum, Venkat; Reddy, Ramana G.

2003-11-01

In this article, the reduction, refining/recycling, and electroplating of aluminum from room-temperature molten salts are reviewed. In addition, the characteristics of several non-conventional organic solvents, electrolytes, and molten salts are evaluated, and the applicability of these melts for production of aluminum is discussed with special attention to ionic liquids. Also reviewed are electrochemical processes and conditions for electrodeposition of aluminum using ionic liquids at near room temperatures.

A temperature-controlled photoelectrochemical cell for quantitative product analysis.

PubMed

Corson, Elizabeth R; Creel, Erin B; Kim, Youngsang; Urban, Jeffrey J; Kostecki, Robert; McCloskey, Bryan D

2018-05-01

In this study, we describe the design and operation of a temperature-controlled photoelectrochemical cell for analysis of gaseous and liquid products formed at an illuminated working electrode. This cell is specifically designed to quantitatively analyze photoelectrochemical processes that yield multiple gas and liquid products at low current densities and exhibit limiting reactant concentrations that prevent these processes from being studied in traditional single chamber electrolytic cells. The geometry of the cell presented in this paper enables front-illumination of the photoelectrode and maximizes the electrode surface area to electrolyte volume ratio to increase liquid product concentration and hence enhances ex situ spectroscopic sensitivity toward them. Gas is bubbled through the electrolyte in the working electrode chamber during operation to maintain a saturated reactant concentration and to continuously mix the electrolyte. Gaseous products are detected by an in-line gas chromatograph, and liquid products are analyzed ex situ by nuclear magnetic resonance. Cell performance was validated by examining carbon dioxide reduction on a silver foil electrode, showing comparable results both to those reported in the literature and identical experiments performed in a standard parallel-electrode electrochemical cell. To demonstrate a photoelectrochemical application of the cell, CO 2 reduction experiments were carried out on a plasmonic nanostructured silver photocathode and showed different product distributions under dark and illuminated conditions.

A temperature-controlled photoelectrochemical cell for quantitative product analysis

NASA Astrophysics Data System (ADS)

Corson, Elizabeth R.; Creel, Erin B.; Kim, Youngsang; Urban, Jeffrey J.; Kostecki, Robert; McCloskey, Bryan D.

2018-05-01

In this study, we describe the design and operation of a temperature-controlled photoelectrochemical cell for analysis of gaseous and liquid products formed at an illuminated working electrode. This cell is specifically designed to quantitatively analyze photoelectrochemical processes that yield multiple gas and liquid products at low current densities and exhibit limiting reactant concentrations that prevent these processes from being studied in traditional single chamber electrolytic cells. The geometry of the cell presented in this paper enables front-illumination of the photoelectrode and maximizes the electrode surface area to electrolyte volume ratio to increase liquid product concentration and hence enhances ex situ spectroscopic sensitivity toward them. Gas is bubbled through the electrolyte in the working electrode chamber during operation to maintain a saturated reactant concentration and to continuously mix the electrolyte. Gaseous products are detected by an in-line gas chromatograph, and liquid products are analyzed ex situ by nuclear magnetic resonance. Cell performance was validated by examining carbon dioxide reduction on a silver foil electrode, showing comparable results both to those reported in the literature and identical experiments performed in a standard parallel-electrode electrochemical cell. To demonstrate a photoelectrochemical application of the cell, CO2 reduction experiments were carried out on a plasmonic nanostructured silver photocathode and showed different product distributions under dark and illuminated conditions.

Non-consumable anode and lining for aluminum electrolytic reduction cell

DOEpatents

Beck, Theodore R.; Brooks, Richard J.

1994-01-01

An oxidation resistant, non-consumable anode, for use in the electrolytic reduction of alumina to aluminum, has a composition comprising copper, nickel and iron. The anode is part of an electrolytic reduction cell comprising a vessel having an interior lined with metal which has the same composition as the anode. The electrolyte is preferably composed of a eutectic of AlF.sub.3 and either (a) NaF or (b) primarily NaF with some of the NaF replaced by an equivalent molar amount of KF or KF and LiF.

Pinpoint and bulk electrochemical reduction of insulating silicon dioxide to silicon.

PubMed

Nohira, Toshiyuki; Yasuda, Kouji; Ito, Yasuhiko

2003-06-01

Silicon dioxide (SiO(2)) is conventionally reduced to silicon by carbothermal reduction, in which the oxygen is removed by a heterogeneous-homogeneous reaction sequence at approximately 1,700 degrees C. Here we report pinpoint and bulk electrochemical methods for removing oxygen from solid SiO(2) in a molten CaCl(2) electrolyte at 850 degrees C. This approach involves a 'contacting electrode', in which a metal wire supplies electrons to a selected region of the insulating SiO(2). Bulk reduction of SiO(2) is possible by increasing the number of contacting points. The same method was also demonstrated with molten LiCl-KCl-CaCl(2) at 500 degrees C. The novelty and relative simplicity of this method might lead to new processes in silicon semiconductor technology, as well as in high-purity silicon production. The methodology may be applicable to electrochemical processing of a wide variety of insulating materials, provided that the electrolyte dissolves the appropriate constituent ion(s) of the material.

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Aulich, Ted R.; Olson, Edwin S.; Jiang, Junhua

2013-03-19

The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be solid.

Electrolyte treatment for aluminum reduction

DOEpatents

Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

2002-01-01

A method of treating an electrolyte for use in the electrolytic reduction of alumina to aluminum employing an anode and a cathode, the alumina dissolved in the electrolyte, the treating improving wetting of the cathode with molten aluminum during electrolysis. The method comprises the steps of providing a molten electrolyte comprised of ALF.sub.3 and at least one salt selected from the group consisting of NaF, KF and LiF, and treating the electrolyte by providing therein 0.004 to 0.2 wt. % of a transition metal or transition metal compound for improved wettability of the cathode with molten aluminum during subsequent electrolysis to reduce alumina to aluminum.

Combination for electrolytic reduction of alumina

DOEpatents

Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

2002-04-30

An electrolytic bath for use during the electrolytic reduction of alumina to aluminum. The bath comprises molten electrolyte having the following ingredients: AlF.sub.3 and at least one salt selected from the group consisting of NaF, KF, and LiF; and about 0.004 wt. % to about 0.2 wt. %, based on total weight of the molten electrolyte, of at least one transition metal or at least one compound of the metal or both. The compound is, a fluoride; oxide, or carbonate. The metal is nickel, iron, copper, cobalt, or molybdenum. The bath is employed in a combination including a vessel for containing the bath and at least one non-consumable anode and at least one dimensionally stable cathode in the bath. Employing the instant bath during electrolytic reduction of alumina to aluminum improves the wetting of aluminum on a cathode by reducing or eliminating the formation of non-metallic deposits on the cathode.

Unusual Passivation Ability of Superconcentrated Electrolytes toward Hard Carbon Negative Electrodes in Sodium-Ion Batteries.

PubMed

Takada, Koji; Yamada, Yuki; Watanabe, Eriko; Wang, Jianhui; Sodeyama, Keitaro; Tateyama, Yoshitaka; Hirata, Kazuhisa; Kawase, Takeo; Yamada, Atsuo

2017-10-04

The passivation of negative electrodes is key to achieving prolonged charge-discharge cycling with Na-ion batteries. Here, we report the unusual passivation ability of superconcentrated Na-salt electrolytes. For example, a 50 mol % sodium bis(fluorosulfonyl)amide (NaFSA)/succinonitrile (SN) electrolyte enables highly reversible Na + insertion into a hard carbon negative electrode without any electrolyte additive, functional binder, or electrode pretreatment. Importantly, an anion-derived passivation film is formed via preferential reduction of the anion upon charging, which can effectively suppress further electrolyte reduction. As a structural characteristic of the electrolyte, most anions are coordinated to multiple Na + cations at high concentration, which shifts the lowest unoccupied molecular orbitals of the anions downward, resulting in preferential anion reduction. The present work provides a new understanding of the passivation mechanism with respect to the coordination state of the anion.

Leaching of manganese from electrolytic manganese residue by electro-reduction.

PubMed

Shu, Jiancheng; Liu, Renlong; Liu, Zuohua; Chen, Hongliang; Tao, Changyuan

2017-08-01

In this study, an improved process for leaching manganese from electrolytic manganese residue (EMR) by electro-reduction was developed. The mechanisms of the electro-reduction leaching were investigated through X-ray diffraction, scanning electron microscopy, X-ray fluorescence, and Brunauer Emmett Teller. The results show that the electric field could change the surface charge distribution of EMR particles, and the high-valent manganese can be reduced by electric field. The leaching efficient of manganese reached 84.1% under the optimal leaching condition: 9.2 wt% H 2 SO 4 , current density of 25 mA/cm 2 , solid-to-liquid ratio of 1:5, and leaching time for 1 h. It is 37.9% higher than that attained without an electric field. Meanwhile, the manganese content in EMR decreased from 2.57% to 0.48%.

Operando Raman Micro Spectroscopy of Polymer Electrolyte Fuel Cells

DTIC Science & Technology

2016-01-16

understanding of the processes such as oxygen reduc- tion reaction (ORR), carbon corrosion, and catalysis process of ORR in PEMFCs catalyzed by Pt or...Journal of Membrane Science, 392, 88 (2012). 46. F. Jaouen, F. Charreteur, and J. P. Dodelet, “Fe-based catalysts for oxygen reduction in PEMFCs

Modular cathode assemblies and methods of using the same for electrochemical reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiedmeyer, Stanley G.; Barnes, Laurel A.; Williamson, Mark A.

Modular cathode assemblies are useable in electrolytic reduction systems and include a basket through which fluid electrolyte may pass and exchange charge with a material to be reduced in the basket. The basket can be divided into upper and lower sections to provide entry for the material. Example embodiment cathode assemblies may have any shape to permit modular placement at any position in reduction systems. Modular cathode assemblies include a cathode plate in the basket, to which unique and opposite electrical power may be supplied. Example embodiment modular cathode assemblies may have standardized electrical connectors. Modular cathode assemblies may bemore » supported by a top plate of an electrolytic reduction system. Electrolytic oxide reduction systems are operated by positioning modular cathode and anode assemblies at desired positions, placing a material in the basket, and charging the modular assemblies to reduce the metal oxide.« less

Modular cathode assemblies and methods of using the same for electrochemical reduction

DOEpatents

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

2014-12-02

Modular cathode assemblies are useable in electrolytic reduction systems and include a basket through which fluid electrolyte may pass and exchange charge with a material to be reduced in the basket. The basket can be divided into upper and lower sections to provide entry for the material. Example embodiment cathode assemblies may have any shape to permit modular placement at any position in reduction systems. Modular cathode assemblies include a cathode plate in the basket, to which unique and opposite electrical power may be supplied. Example embodiment modular cathode assemblies may have standardized electrical connectors. Modular cathode assemblies may be supported by a top plate of an electrolytic reduction system. Electrolytic oxide reduction systems are operated by positioning modular cathode and anode assemblies at desired positions, placing a material in the basket, and charging the modular assemblies to reduce the metal oxide.

Comparative study on the removal of COD from POME by electrocoagulation and electro-Fenton methods: Process optimization

NASA Astrophysics Data System (ADS)

Chairunnisak, A.; Arifin, B.; Sofyan, H.; Lubis, M. R.; Darmadi

2018-03-01

This research focuses on the Chemical Oxygen Demand (COD) treatment in palm oil mill effluent by electrocoagulation and electro-Fenton methods to solve it. Initially, the aqueous solution precipitates in acid condition at pH of about two. This study focuses on the palm oil mill effluent degradation by Fe electrodes in a simple batch reactor. This work is conducted by using different parameters such as voltage, electrolyte concentration of NaCl, volume of H2O2 and operation time. The processing of data resulted is by using response surface method coupled with Box-Behnken design. The electrocoagulation method results in the optimum COD reduction of 94.53% from operating time of 39.28 minutes, 20 volts, and without electrolyte concentration. For electro-Fenton process, experiment points out that voltage 15.78 volts, electrolyte concentration 0.06 M and H2O2 volume 14.79 ml with time 35.92 minutes yield 99.56% degradation. The result concluded that the electro-Fenton process was more effective to degrade COD of the palm-oil-mill effluent compared to electrocoagulation process.

Apparatus for the electrolytic production of metals

DOEpatents

Sadoway, Donald R.

1993-01-01

Improved electrolytic cells for producing metals by the electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells, at least one electrode includes a protective layer comprising an oxide of the cell product metal formed upon an alloy of the cell product metal and a more noble metal. In the case of an aluminum reduction cell, the electrode can comprise an alloy of aluminum with copper, nickel, iron, or combinations thereof, upon which is formed an aluminum oxide protective layer.

Hydrothermal Synthesis of Platinum-Group-Metal-Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis

DOE PAGES

Gokhale, Rohan; Tsui, Lok-Kun; Roach, Kristin; ...

2017-12-07

In this paper, a hydrothermal approach to generate a platinum-group-metal-free (PGM-free) Fe-N-C catalyst for the oxygen reduction reaction (ORR) is introduced. The process involves partial carbonization by hydrothermal means followed by thermal treatment to obtain the final catalysts. Detailed X-ray scattering analysis of the glucose-imidazole catalysts (termed as GLU-IMID-C catalysts), obtained for the first time with the use of CarbonXS GUI program, reveals the presence of face-centered cubic (FCC) iron nanoparticles embedded in partially graphitic carbon in all catalyst variations. We also report the physical characterization of these catalysts by using X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area analysis, and transmissionmore » electron microscopy. The electrocatalytic behavior of the catalysts towards oxygen reduction is studied separately in acidic and alkaline electrolytes by rotating ring disk electrode measurements. The catalysts exhibit high ORR activity in acidic (0.5 M H 2SO 4) and alkaline (0.1 M KOH) electrolytes. Lastly, a precursor structure-performance relationship of these catalysts and their performance trends in both electrolytes has been discussed in this work.« less

Hydrothermal Synthesis of Platinum-Group-Metal-Free Catalysts: Structural Elucidation and Oxygen Reduction Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gokhale, Rohan; Tsui, Lok-Kun; Roach, Kristin

In this paper, a hydrothermal approach to generate a platinum-group-metal-free (PGM-free) Fe-N-C catalyst for the oxygen reduction reaction (ORR) is introduced. The process involves partial carbonization by hydrothermal means followed by thermal treatment to obtain the final catalysts. Detailed X-ray scattering analysis of the glucose-imidazole catalysts (termed as GLU-IMID-C catalysts), obtained for the first time with the use of CarbonXS GUI program, reveals the presence of face-centered cubic (FCC) iron nanoparticles embedded in partially graphitic carbon in all catalyst variations. We also report the physical characterization of these catalysts by using X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area analysis, and transmissionmore » electron microscopy. The electrocatalytic behavior of the catalysts towards oxygen reduction is studied separately in acidic and alkaline electrolytes by rotating ring disk electrode measurements. The catalysts exhibit high ORR activity in acidic (0.5 M H 2SO 4) and alkaline (0.1 M KOH) electrolytes. Lastly, a precursor structure-performance relationship of these catalysts and their performance trends in both electrolytes has been discussed in this work.« less

Platinum nanoparticles on carbon-nanotube support prepared by room-temperature reduction with H2 in ethylene glycol/water mixed solvent as catalysts for polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Zheng, Yuying; Dou, Zhengjie; Fang, Yanxiong; Li, Muwu; Wu, Xin; Zeng, Jianhuang; Hou, Zhaohui; Liao, Shijun

2016-02-01

Polyol approach is commonly used in synthesizing Pt nanoparticles in polymer electrolyte membrane fuel cells. However, the application of this process consumes a great deal of time and energy, as the reduction of precursors requires elevated temperatures and several hours. Moreover, the ethylene glycol and its oxidizing products bound to Pt are difficult to remove. In this work, we utilize the advantages of ethylene glycol and prepare Pt nanoparticles through a room-temperature hydrogen gas reduction in an ethylene glycol/water mixed solvent, which is followed by subsequent harvesting by carbon nanotubes as electrocatalysts. This method is simple, facile, and time-efficient, as the entire room-temperature reduction process is completed in a few minutes. As the solvent changes from water to an ethylene glycol/water mix, the size of Pt nanoparticles varies from 10 to 3 nm and their shape transitions from polyhedral to spherical. Pt nanoparticles prepared in a 1:1 volume ratio mixture of ethylene glycol/water are uniformly dispersed with an average size of ∼3 nm. The optimized carbon nanotube-supported Pt electrocatalyst exhibits excellent methanol oxidation and oxygen reduction activities. This work demonstrates the potential use of mixed solvents as an approach in materials synthesis.

Additive effect on reductive decomposition and binding of carbonate-based solvent toward solid electrolyte interphase formation in lithium-ion battery.

PubMed

Ushirogata, Keisuke; Sodeyama, Keitaro; Okuno, Yukihiro; Tateyama, Yoshitaka

2013-08-14

The solid-electrolyte interphase (SEI) formed through the reductive decomposition of solvent molecules plays a crucial role in the stability and capability of a lithium-ion battery (LIB). Here we investigated the effects of adding vinylene carbonate (VC) to ethylene carbonate (EC) solvent, a typical electrolyte in LIBs, on the reductive decomposition. We focused on both thermodynamics and kinetics of the possible processes and used density functional theory-based molecular dynamics with explicit solvent and Blue-moon ensemble technique for the free energy change. We considered Li(+) in only EC solvent (EC system) and in EC solvent with a VC additive (EC/VC system) to elucidate the additive effects. In addition to clarifying the equilibrium properties, we evaluated the free energy changes along several EC or VC decomposition pathways under one-electron (1e) reduction condition. Two-electron (2e) reduction and attacks of anion radicals to intact molecules were also examined. The present results completely reproduce the gaseous products observed in the experiments. We also found a new mechanism involving the VC additive: the VC additive preferentially reacts with the EC anion radical to suppress the 2e reduction of EC and enhance the initial SEI formation, contrary to the conventional scenario in which VC additive is sacrificially reduced and its radical oligomerization becomes the source of SEI. Because our mechanism needs only 1e reduction, the irreversible capacity at the SEI formation will decrease, which is also consistent with the experimental observations. These results reveal the primary role of VC additive in the EC solvent.

Electrodeposition of platinum on highly oriented pyrolytic graphite. Part I: electrochemical characterization.

PubMed

Lu, Guojin; Zangari, Giovanni

2005-04-28

The electrochemical deposition of Pt on highly oriented pyrolytic graphite (HOPG) from H2PtCl6 solutions was investigated by cyclic voltammetry and chronoamperometry. The effects of deposition overpotential, H2PtCl6 concentration, supporting electrolyte, and anion additions on the deposition process were evaluated. Addition of chloride inhibits Pt deposition due to adsorption on the substrate and blocking of reduction sites, while SO4(2-) and ClO4- slightly promote Pt reduction. By comparing potentiostatic current-time transients with the Scharifker-Hills model, a transition from progressive to instantaneous nucleation was observed when increasing the deposition overpotential. Following addition of chloride anions the fit of experimental transients with the instantaneous nucleation mode improves, while the addition of SO4(2-) induces only small changes. Chloride anions strongly inhibit the reduction process, which is shifted in the cathodic direction. The above results indicate that the most appropriate conditions for growing Pt nanoparticles on HOPG with narrow size distribution are to use an H2PtCl6 solution with HCl as supporting electrolyte and to apply a high cathodic overpotential.

Bath for electrolytic reduction of alumina and method therefor

DOEpatents

Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

2001-07-10

An electrolytic bath for use during the electrolytic reduction of alumina to aluminum. The bath comprises a molten electrolyte having the following ingredients: (a) AlF.sub.3 and at least one salt selected from the group consisting of NaF, KF, and LiF; and (b) about 0.004 wt. % to about 0.2 wt. %, based on total weight of the molten electrolyte, of at least one transition metal or at least one compound of the metal or both. The compound may be, for example, a fluoride, oxide, or carbonate. The metal can be nickel, iron, copper, cobalt, or molybdenum. The bath can be employed in a combination that includes a vessel for containing the bath and at least one non-consumable anode and at least one dimensionally stable cathode in the bath. Employing the bath of the present invention during electrolytic reduction of alumina to aluminum can improve the wetting of aluminum on a cathode by reducing or eliminating the formation of non-metallic deposits on the cathode.

Towards the next generation of solid oxide fuel cells operating below 600 °c with chemically stable proton-conducting electrolytes.

PubMed

Fabbri, Emiliana; Bi, Lei; Pergolesi, Daniele; Traversa, Enrico

2012-01-10

The need for reducing the solid oxide fuel cell (SOFC) operating temperature below 600 °C is imposed by cost reduction, which is essential for widespread SOFC use, but might also disclose new applications. To this aim, high-temperature proton-conducting (HTPC) oxides have gained widespread interest as electrolyte materials alternative to oxygen-ion conductors. This Progress Report describes recent developments in electrolyte, anode, and cathode materials for protonic SOFCs, addressing the issue of chemical stability, processability, and good power performance below 600 °C. Different fabrication methods are reported for anode-supported SOFCs, obtained using state-of-the-art, chemically stable proton-conducting electrolyte films. Recent findings show significant improvements in the power density output of cells based on doped barium zirconate electrolytes, pointing out towards the feasibility of the next generation of protonic SOFCs, including a good potential for the development of miniaturized SOFCs as portable power supplies. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feasibility tests of nickel as a containment material of molten Li2O-LiCl salt containing Li metal at 650 °C during electrolytic reduction

NASA Astrophysics Data System (ADS)

Choi, Eun-Young; Lee, Jeong

2017-11-01

In this study, we investigated the feasibility of nickel (Ni) as a material to contain molten Li2O-LiCl salt containing lithium (Li) metal at 650 °C as an electrolyte during the electrolytic reduction process of pyroprocessing (also known as oxide reduction, OR). First, the behaviors of Ni in four different LiCl salts (0.1 wt% Li-LiCl, 1 and 8 wt% Li2O-LiCl, and 8 wt% Li2O-0.1 wt% Li-LiCl) in an argon atmosphere were examined through immersion tests. Then, Ni was used as a vessel material for five consecutive OR runs of simulated oxide fuel using 1.0 wt% Li2O-LiCl salt. The tested Ni was analyzed by microbalance, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Concentrations of Ni in the salt were measured using inductively coupled plasma atomic emission spectroscopy. No corrosion product of Ni, except Cr2Ni3, was observed on the Ni used for both the salt-immersion tests and the OR runs because the Ni was not exposed to oxygen gas. However, leaching of Ni in the OR salt containing excessive Li metal was observed. Therefore, Ni can be used as the salt containment material in the OR process when excessive Li metal and oxygen gas in the salt are maintained at low levels.

Non-electrolytic synthesis of copper oxide/carbon nanocomposite by surface plasma in super-dehydrated ethanol

NASA Astrophysics Data System (ADS)

Kozak, Dmytro S.; Sergiienko, Ruslan A.; Shibata, Etsuro; Iizuka, Atsushi; Nakamura, Takashi

2016-02-01

Electrolytic processes are widely used to synthesize different nanomaterials and it does not depend on what kind of the method has been applied (wet-chemistry, sonochemistry, plasma chemistry, electrolysis and so on). Generally, the reactions in the electrolyte are considered to be reduction/oxidation (REDOX) reactions between chemical reagents or the deposition of matter on the electrodes, in line with Faraday’s law. Due to the presence of electroconductive additives in any electrolyte, the polarization effect of polar molecules conducting an electrical current disappears, when external high-strength electric field is induced. Because initially of the charge transfer always belongs of electroconductive additive and it does not depend on applied voltage. The polarization of ethanol molecules has been applied to conduct an electric current by surface plasma interaction for the synthesis of a copper oxide/carbon nanocomposite material.

Fluid/electrolyte and endocrine changes in space flight

NASA Technical Reports Server (NTRS)

Huntoon, Carolyn Leach

1989-01-01

The primary effects of space flight that influence the endocrine system and fluid and electrolyte regulation are the reduction of hydrostatic gradients, reduction in use and gravitational loading of bone and muscle, and stress. Each of these sets into motion a series of responses that culminates in alteration of some homeostatic set points for the environment of space. Set point alterations are believed to include decreases in venous pressure; red blood cell mass; total body water; plasma volume; and serum sodium, chloride, potassium, and osmolality. Serum calcium and phosphate increase. Hormones such as erythropoietin, atrial natriuretic peptide, aldosterone, cortisol, antidiuretic hormone, and growth hormone are involved in the dynamic processes that bring about the new set points. The inappropriateness of microgravity set points for 1-G conditions contributes to astronaut postflight responses.

Process for preparing a chemical compound enriched in isotope content

DOEpatents

Michaels, Edward D.

1982-01-01

A process to prepare a chemical enriched in isotope content which includes: (a) A chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; (b) the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; (c) the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; (d) the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products.

Electrochemical Interfaces and Electrode Processes.

DTIC Science & Technology

1984-08-15

reduction of 02 on such surfaces has been of special interest. Some of these complexes such as the iron tetrasulfonated phthalocyanines (TSPc) have high...high area carbon electrodes in porous carbon electrolyte structures (14,22,27). We have been successful in examining the Fe phthalocyanine and Co...Zagal, B. Z. Nikolic and R. R. Adzic, 1 May 1979. 50. A Mechanistic Study of 02 Reduction on Water Soluble Phthalocyanines Adsorbed on Graphite

Extraction of manganese from electrolytic manganese residue by bioleaching.

PubMed

Xin, Baoping; Chen, Bing; Duan, Ning; Zhou, Changbo

2011-01-01

Extraction of manganese from electrolytic manganese residues using bioleaching was investigated in this paper. The maximum extraction efficiency of Mn was 93% by sulfur-oxidizing bacteria at 4.0 g/l sulfur after bioleaching of 9days, while the maximum extraction efficiency of Mn was 81% by pyrite-leaching bacteria at 4.0 g/l pyrite. The series bioleaching first by sulfur-oxidizing bacteria and followed by pyrite-leaching bacteria evidently promoted the extraction of manganese, witnessing the maximum extraction efficiency of 98.1%. In the case of sulfur-oxidizing bacteria, the strong dissolution of bio-generated sulfuric acid resulted in extraction of soluble Mn2+, while both the Fe2+ catalyzed reduction of Mn4+ and weak acidic dissolution of Mn2+ accounted for the extraction of manganese with pyrite-leaching bacteria. The chemical simulation of bioleaching process further confirmed that the acid dissolution of Mn2+ and Fe2+ catalyzed reduction of Mn4+ were the bioleaching mechanisms involved for Mn extraction from electrolytic manganese residues. Copyright © 2010 Elsevier Ltd. All rights reserved.

Direct electrochemical reduction of metal-oxides

DOEpatents

Redey, Laszlo I.; Gourishankar, Karthick

2003-01-01

A method of controlling the direct electrolytic reduction of a metal oxide or mixtures of metal oxides to the corresponding metal or metals. A non-consumable anode and a cathode and a salt electrolyte with a first reference electrode near the non-consumable anode and a second reference electrode near the cathode are used. Oxygen gas is produced and removed from the cell. The anode potential is compared to the first reference electrode to prevent anode dissolution and gas evolution other than oxygen, and the cathode potential is compared to the second reference electrode to prevent production of reductant metal from ions in the electrolyte.

Stability of yttria-stabilized zirconia during pyroprocessing tests

NASA Astrophysics Data System (ADS)

Choi, Eun-Young; Lee, Jeong; Lee, Sung-Jai; Kim, Sung-Wook; Jeon, Sang-Chae; Cho, Soo Haeng; Oh, Seung Chul; Jeon, Min Ku; Lee, Sang Kwon; Kang, Hyun Woo; Hur, Jin-Mok

2016-07-01

In this study, the feasibility of yttria-stabilized zirconia (YSZ) was investigated for use as a ceramic material, which can be commonly used for both electrolytic reduction and electrorefining. First, the stability of YSZ in salts for electrolytic reduction and electrorefining was examined. Then, its stability was demonstrated by a series of pyroprocessing tests, such as electrolytic reduction, LiCl distillation, electrorefining, and LiClsbnd KCl distillation, using a single stainless steel wire mesh basket containing fuel and YSZ. A single basket was used by its transportation from one test to subsequent tests without the requirements for unloading.

Carbon black dispersion pre-plating technology for printed wire board manufacturing. Final technology evaluation report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Folsom, D.W.; Gavaskar, A.R.; Jones, J.A.

1993-10-01

The project compared chemical use, waste generation, cost, and product quality between electroless copper and carbon-black-based preplating technologies at the printed wire board (PWB) manufacturing facility of McCurdy Circuits in Orange, CA. The carbon-black based preplating technology evaluated is used as an alternative process for electroless copper (EC) plating of through-holes before electrolytic copper plating. The specific process used at McCurdy is the BlackHole (BH) technology process, which uses a dispersion of carbon black in an aqueous solution to provide a conductive surface for subsequent electrolytic copper plating. The carbon-black dispersion technology provided effective waste reduction and long-term cost savings.more » The economic analysis determined that the new process was cost efficient because chemical use was reduced and the process proved more efficient; the payback period was less than 4 yrs.« less

Process for preparing a chemical compound enriched in isotope content. [nitrogen 15-enriched nitric acid

DOEpatents

Michaels, E.D.

1981-02-25

A process to prepare a chemical enriched in isotope content includes: a chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products. A particular embodiment of the process in the production of nitrogen-15-enriched nitric acid.

Evaluation of selected chemical processes for production of low-cost silicon

NASA Technical Reports Server (NTRS)

Blocher, J. M., Jr.; Browning, M. F.; Wilson, W. J.; Carmichael, D. C.

1976-01-01

Plant construction costs and manufacturing costs were estimated for the production of solar-grade silicon by the reduction of silicon tetrachloride in a fluidized bed of seed particles, and several modifications of the iodide process using either thermal decomposition on heated filaments (rods) or hydrogen reduction in a fluidized bed of seed particles. Energy consumption data for the zinc reduction process and each of the iodide process options are given and all appear to be acceptable from the standpoint of energy pay back. Information is presented on the experimental zinc reduction of SiCl4 and electrolytic recovery of zinc from ZnCl2. All of the experimental work performed thus far has supported the initial assumption as to technical feasibility of producing semiconductor silicon by the zinc reduction or iodide processes proposed. The results of a more thorough thermodynamic evaluation of the iodination of silicon oxide/carbon mixtures are presented which explain apparent inconsistencies in an earlier cursory examination of the system.

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Aulich, Ted R [Grand Forks, ND; Olson, Edwin S [Grand Forks, ND; Jiang, Junhua [Grand Forks, ND

2012-04-10

The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia, at low temperature and pressure, preferably at ambient temperature and pressure, utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen or hydrogen equivalent. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source or a hydrogen equivalent such as carbon monoxide or a mixture of carbon monoxide and hydrogen at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be aqueous, non-aqueous, or solid.

Preparation of Ferrotitanium Alloys by Electrolysis-Assisted Calciothermic Reduction of Ilmenite in Equimolar CaCl2-NaCl Electrolyte: Effect of Calcium Oxide

NASA Astrophysics Data System (ADS)

Zhou, Zhongren; Zhang, Yingjie; Hua, Yixin; Xu, Cunying; Dong, Peng; Zhang, Qibo; Wang, Ding

2018-04-01

The effect of CaO content on the preparation of ferrotitanium alloys from ilmenite with the method of the electrolysis-assisted calciothermic reduction has been investigated by use of ilmenite powders as raw materials that positions them next to the cathodic molybdenum plate, equimolar CaCl2-NaCl molten salt with 2-7 mol.% CaO as electrolyte and graphite as anode at 700°C with cell voltage of 2.8 V under argon atmosphere. It is demonstrated that increasing the reactant CaO content is beneficial to the calciothermic reduction of ilmenite and the intermediate CaTiO3. Experimental results also show that after 14 h of calciothermic reduction process, the products are ferrotitanium alloys and the specific energy consumption is only about 10.21 kWh kg-1 when adding 5 mol.% CaO into equimolar CaCl2-NaCl molten salt and approximately 14.40 kWh kg-1 when CaO content is increased to 7 mol.%.

Lunar Metal Oxide Electrolysis with Oxygen and Photovoltaic Array Production Applications

NASA Technical Reports Server (NTRS)

Curreri, P. A.; Ethridge, E.; Hudson, S.; Sen, S.

2006-01-01

This paper presents the results of a Marshall Space Flight Center funded effort to conduct an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis (MOE) process to produce oxygen and metal from lunar resources to support human exploration of space. Oxygen extracted from lunar materials can be used for life support and propellant, and silicon and metallic elements produced can be used for in situ fabrication of thin-film solar cells for power production. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis, MOE, is chosen for extraction, since the electron is the most practical reducing agent. MOE was also chosen for following reasons. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. In the experiments reported here, melts containing iron oxide were electrolyzed in a low temperature supporting oxide electrolyte (developed by D. Sadoway, MIT). The production of oxygen and reduced iron were observed. Electrolysis was also performed on the supporting electrolyte with JSC-1 Lunar Simulant. The cell current for the supporting electrolyte alone is negligible while the current for the electrolyte with JSC-1 shows significant current and a peak at about -0.6 V indicating reductive reaction in the simulant.

In Situ Potentiodynamic Analysis of the Electrolyte/Silicon Electrodes Interface Reactions - A Sum Frequency Generation Vibrational Spectroscopy Study

DOE PAGES

Horowitz, Yonatan; Han, Hui-Ling; Ross, Philip N.; ...

2015-12-11

The key factor in long-term use of batteries is the formation of an electrically insulating solid layer that allows lithium ion transport but stops further electrolyte redox reactions on the electrode surface, hence solid electrolyte interphase (SEI). In this paper, we have studied a common electrolyte, 1.0 M LiPF 6/ethylene carbonate (EC)/diethyl carbonate (DEC), reduction products on crystalline silicon (Si) electrodes in a lithium (Li) half-cell system under reaction conditions. We employed in situ sum frequency generation vibrational spectroscopy (SFG-VS) with interface sensitivity in order to probe the molecular composition of the SEI surface species under various applied potentials wheremore » electrolyte reduction is expected. We found that, with a Si(100)-hydrogen terminated wafer, a Si-ethoxy (Si-OC 2H 5) surface intermediate forms due to DEC decomposition. Our results suggest that the SEI surface composition varies depending on the termination of Si surface, i.e., the acidity of the Si surface. We provide the evidence of specific chemical composition of the SEI on the anode surface under reaction conditions. This supports an electrochemical electrolyte reduction mechanism in which the reduction of the DEC molecule to an ethoxy moiety plays a key role. Finally, these findings shed new light on the formation mechanism of SEI on Si anodes in particular and on SEI formation in general.« less

Experimental Study of Hydroxy Gas (HHO) Production with Variation in Current, Voltage and Electrolyte Concentration

NASA Astrophysics Data System (ADS)

Alam, Noor; Pandey, K. M.

2017-08-01

In this paper, work has been carried out experimentally for the investigation of the effects of variation incurrent, voltage, temperature, chemical concentration and reaction time on the amount of hydroxy gas produced. Further effects on the overall electrolysis efficiency of advance alkaline water is also studied. The hydroxy gas (HHO) has been produced experimentally by the electrolysis of alkaline water with parallel plate electrode of 316L-grade stainless steel. The electrode has been selected on the basis of corrosion resistance and inertness with respect to electrolyte (KOH). The process used for the production of HHO is conventional as compared to the other production processes because of reduced energy consumption, less maintenance and low setup cost. From the experimental results, it has been observed that with increase in voltage, temperature and electrolyte concentration of alkaline solution, the production of hydroxy gas has increased about 30 to 40% with reduction in electrical energy consumption.

Advances in the electrodeposition of aluminum from ionic liquid based electrolytes

NASA Astrophysics Data System (ADS)

Leadbetter, Kirt C.

Aluminum plating is of considerable technical and economic interest because it provides an eco-friendly substitute for cadmium coatings used on many military systems. However, cadmium has been determined to be a significant environmental safety and occupational health (ESOH) hazard because of its toxicity and carcinogenic nature. Furthermore, the cost of treating and disposing of generated wastes, which often contain cyanide, is costly and is becoming prohibitive in the face of increasingly stringent regulatory standards. The non-toxic alternative aluminum is equivalent or superior in performance to cadmium. In addition, it could serve to provide an alternative to hexavalent chromium coatings used on military systems for similar reasons to that of cadmium. Aluminum is a beneficial alternative in that it demonstrates self-healing corrosion resistance in the form of a tightly-bound, impervious oxide layer. A successfully plated layer would be serviceable over a wider temperature range, 925 °F for aluminum compared to 450 oF for cadmium. In addition, an aluminum layer can be anodized to make it non-conducting and colorable. In consideration of the plating process, aluminum cannot be deposited from aqueous solutions because of its reduction potential. Therefore, nonaqueous electrolytes are required for deposition. Currently, aluminum can be electrodeposited in nonaqueous processes that use hazardous chemicals such as toluene and pyrophoric aluminum alkyls. Electrodeposition from ionic liquids provides the potential for a safer method that could be easily scaled up for industrial application. The plating process could be performed at a lower temperature and higher current density than other commercially available aluminum electrodeposition processes; thus a reduced process cost could be possible. The current ionic liquid based electrolytes are more expensive; however production on a larger scale and a long electrolyte lifetime are associated with a reduction in price. Advancements of this nonaqueous aluminum plating process have the potential to lead to a novel and competitive commercial aluminum deposition process. In this investigation aluminum electrodeposition from ionic liquid based electrolytes onto steel, copper and magnesium substrates without conversion coatings or strike layers was evaluated in six different ionic liquid based electrolytes in two technical setups. Three of which are commercially available aluminum plating electrolytes, three of which, discussed in literature were created on site by research personnel in the laboratory. The three commercially available electrolytes were: 1-Butyl-3-methylimidazolium chloride ([BMIm]Cl) * 1.5 AlCl3 with proprietary additives from IoLiTec, 1-Ethyl-3-methylimidazolium chloride ([EMIm]Cl) * 1.5 AlCl3 with proprietary additives from IoLiTec, and BasionicsTM AL-02, an aluminum plating electrolyte containing [EMIm]Cl * 1.5 AlCl3 with additives from BASF. The three electrolytes created on site were based on the 1-ethyl-3-methylimidazolium chloride ionic liquid with added 1.5 AlCl3 and one with added sodium dodecyl sulfate. Small scale plating tests in a 25-mL plating cell were conducted to provide a comparative analysis of the six different electrolytes considered. From these investigations, two were chosen to be evaluated in a larger 1-liter plating cell; designed and constructed to provide a more realistic evaluation of plating parameters with selected electrolytes to better portray industrial electroplating conditions. The effect of current density (10-40 mA/cm 2), temperature (30-90° Celsius) and plating bath agitation on current efficiency, corrosion resistance by the ASTM B117 method, adhesion, microstructure, and chemical composition (evaluated with energy-dispersive x-ray spectroscopy) of the plated Al-layer was explored in both the 25-mL and 1-L plating cell investigations. In addition development of pre- and post-treatment processes for the metal substrates was attempted. While previous investigations focused on one or two of these topics, this research seeks to investigate all discussed phenomena and characteristics. Additionally, there is little research that reports on the adhesion performance of aluminum coatings from ionic liquids. Also, corrosion investigations are limited to all but a few publications. So too, the deposition of aluminum in a larger, more realistic plating cell has never been thoroughly investigated. This is key if a practical application of the technology is ever to be realized. In sum, correlations were drawn between electrolyte, current density, temperature and bath agitation with quality and characteristic of electrodeposited aluminum layers. The overriding goal to create an acceptably competitive aluminum coating process to replace cadmium and compete with other commercial aluminum deposition processes was not successful. Competitiveness was evaluated as per the discussed characteristics and so also, by a comparison to physical samples created in a more realistic plating cell to AlumiPlate aluminum coatings.

Antimicrobial effects of electrolytic products of sodium chloride--comparative evaluation with sodium hypochlorite solution and efficacy in handwashing.

PubMed

Hitomi, S; Baba, S; Yano, H; Morisawa, Y; Kimura, S

1998-11-01

We examined the in vitro bactericidal effects and efficacy on handwashing of water containing electrolytic products of sodium chloride (electrolytic water). The electrolytic water, whose pH and concentration of free residual chlorine were 6.7-6.9 and 20-22 ppm, respectively, showed equal reduction of both Staphylococcus aureus and Escherichia coli to dilution of commercially available sodium hypochlorite containing 60 ppm of free residual chlorine. This bactericidal effect was calculated to be due to hypochlorous acid, based on the pH and the amount of chlorine in solution. Handwashing with the electrolytic water reduced the numbers of S. aureus on hands by 1/10(2), while running water and 0.2% benzalkonium chloride with 80% ethanol gave a 1/10 and 1/10(5) reduction, respectively. We conclude that electrolytic water might be applicable for handwashing in place of running water.

Charge transfer mediator based systems for electrocatalytic oxygen reduction

DOEpatents

Stahl, Shannon S.; Gerken, James B.; Anson, Colin W.

2017-11-07

Disclosed are systems for the electrocatalytic reduction of oxygen, having redox mediator/redox catalyst pairs and an electrolyte solution in contact with an electrode. The redox mediator is included in the electrolyte solution, and the redox catalyst may be included in the electrolyte solution, or alternatively, may be in contact with the electrolyte solution. In one form a cobalt redox catalyst is used with a quinone redox mediator. In another form a nitrogen oxide redox catalyst is used with a nitroxyl type redox mediator. The systems can be used in electrochemical cells wherein neither the anode nor the cathode comprise an expensive metal such as platinum.

Charge transfer mediator based systems for electrocatalytic oxygen reduction

DOEpatents

Stahl, Shannon S.; Gerken, James B.; Anson, Colin W.

2017-07-18

Disclosed are systems for the electrocatalytic reduction of oxygen, having redox mediator/redox catalyst pairs and an electrolyte solution in contact with an electrode. The redox mediator is included in the electrolyte solution, and the redox catalyst may be included in the electrolyte solution, or alternatively, may be in contact with the electrolyte solution. In one form a cobalt redox catalyst is used with a quinone redox mediator. In another form a nitrogen oxide redox catalyst is used with a nitroxyl type redox mediator. The systems can be used in electrochemical cells wherein neither the anode nor the cathode comprise an expensive metal such as platinum.

Bath for electrolytic reduction of alumina and method therefor

DOEpatents

Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

2002-11-26

An electrolytic bath for use during the electrolytic reduction of alumina to aluminum. The bath comprises a molten electrolyte having the following ingredients: (a) AlF.sub.3 and at least one salt selected from the group consisting of NaF, KF, and LiF; and (b) about 0.004 wt. % to about 0.2 wt. %, based on total weight of the molten electrolyte, of at least one transition metal or at least one compound of the metal or both. The compound may be, for example, a fluoride, oxide, or carbonate. The metal can be nickel, iron, copper, cobalt, or molybdenum. The bath can be employed in a combination that includes a vessel for containing the bath and at least one non-consumable anode and at least one dimensionally stable cathode in the bath. Employing the bath of the present invention during electrolytic reduction of alumina to aluminum can improve the wetting of aluminum on a cathode by reducing or eliminating the formation of non-metallic deposits on the cathode. Removing sulfur from the bath can also minimize cathode deposits. Aluminum formed on the cathode can be removed directly from the cathode.

In-situ chemical reduction produced graphene paper for flexible supercapacitors with impressive capacitive performance

NASA Astrophysics Data System (ADS)

Ye, Xingke; Zhu, Yucan; Tang, Zhonghua; Wan, Zhongquan; Jia, Chunyang

2017-08-01

For practical applications of graphene-based materials in flexible supercapacitors, a technological breakthrough is currently required to fabricate high-performance graphene paper by a facile method. Herein, highly conductive (∼6900 S m-1) graphene paper with loose multilayered structure is produced by a high-efficiency in-situ chemical reduction process, which assembles graphite oxide suspensions into film and simultaneously conducts chemical reduction. Graphene papers with different parameters (including different types and doses of reductants, different thicknesses and areas of films) are successfully fabricated through this in-situ chemical reduction method. Meanwhile, the influences of the graphene papers with different parameters upon the supercapacitor performance are systematically investigated. Flexible supercapacitor based on the graphene paper exhibits high areal capacitance (152.4 mF cm-2 at current density of 2.0 mA cm-2 in aqueous electrolyte), and excellent rate performance (88.7% retention at 8.0 mA cm-2). Furthermore, bracelet-shaped all-solid supercapacitor with fascinating cycling stability (96.6% retention after 10 000 cycles) and electrochemical stability (an almost negligible capacity loss under different bending states and 99.6% retention after 4000 bending cycles) is established by employing the graphene paper electrode material and polymer electrolyte.

Polymer Electrolyte Fuel Cells Employing Heteropolyacids as Redox Mediators for Oxygen Reduction Reactions: Pt-Free Cathode Systems.

PubMed

Matsui, Toshiaki; Morikawa, Eri; Nakada, Shintaro; Okanishi, Takeou; Muroyama, Hiroki; Hirao, Yoshifumi; Takahashi, Tsuyoshi; Eguchi, Koichi

2016-07-20

In this study, the heteropolyacids of H3+xPVxMO12-xO40 (x = 0, 2, and 3) were applied as redox mediators for the oxygen reduction reaction in polymer electrolyte fuel cells, of which the cathode is free from the usage of noble metals such as Pt/C. In this system, the electrochemical reduction of heteropolyacid over the carbon cathode and the subsequent reoxidation of the partially reduced heteropolyacid by exposure to the dissolved oxygen in the regenerator are important processes for continuous power generation. Thus, the redox properties of catholytes containing these heteropolyacids were investigated in detail. The substitution quantity of V in the heteropolyacid affected the onset reduction potential as well as the reduction current density, resulting in a difference in cell performance. The chemical composition of heteropolyacid also had a significant impact on the reoxidation property. Among the three compounds, H6PV3Mo9O40 was the most suitable redox mediator. Furthermore, the pH of the catholyte was found to be the crucial factor in determining the reoxidation rate of partially reduced heteropolyacid as well as cell performance.

Reduction of Electrolyte Components on a Coated Si Anode of Lithium-Ion Batteries.

PubMed

Gomez-Ballesteros, Jose L; Balbuena, Perla B

2017-07-20

Surface modification of Si anodes in Li-ion batteries by deposition of a thin alucone coating has demonstrated an effective way to help maintain a stable anode/electrolyte interface and good battery performance. In this work, we investigate the interactions and reactivity of the film with electrolyte components using ab initio molecular dynamics simulations. Adsorption of solvent molecules (ethylene carbonate, EC) and salt (LiPF 6 ) and reduction by two mechanisms depending on the Li content of the film (yielding open EC adsorbed on the film or C 2 H 4 + CO 3 2- ) take place near the film/electrolyte and film/anode interfaces. Reaction products incorporate into the structure of the film and create a new kind of solid-electrolyte interphase layer.

Reduction of Electrolyte Components on a Coated Si Anode of Lithium-Ion Batteries

DOE PAGES

Gomez-Ballesteros, Jose L.; Balbuena, Perla B.

2017-07-07

Surface modification of Si anodes in Li-ion batteries by deposition of a thin alucone coating has demonstrated an effective way to help maintain a stable anode/electrolyte interface and good battery performance. In this paper, we investigate the interactions and reactivity of the film with electrolyte components using ab initio molecular dynamics simulations. Adsorption of solvent molecules (ethylene carbonate, EC) and salt (LiPF 6), and reduction by two mechanisms depending on the Li content of the film (yielding open EC adsorbed on the film or C 2H 4 + CO 3 2-) take place near the film/electrolyte and film/anode interfaces. Finally,more » reactions products incorporate to the structure of the film and create a new kind of solid-electrolyte interphase layer.« less

Molten carbonate fuel cell reduction of nickel deposits

DOEpatents

Smith, James L.; Zwick, Stanley A.

1987-01-01

A molten carbonate fuel cell with anode and cathode electrodes and an eleolyte formed with two tile sections, one of the tile sections being adjacent the anode and limiting leakage of fuel gas into the electrolyte with the second tile section being adjacent the cathode and having pores sized to permit the presence of oxygen gas in the electrolyte thereby limiting the formation of metal deposits caused by the reduction of metal compositions migrating into the electrolyte from the cathode.

Molecular modification of highly degenerate semiconductor as an active electrode to enhance the performance of supercapacitors

NASA Astrophysics Data System (ADS)

Mundinamani, S. P.; Rabinal, M. K.

2014-12-01

Highly conducting antimony doped tin oxide (SnO2:Sb) films are electrografted with suitable organic molecules to study their electrolytic behavior. A series of organic molecules, such as heptanethiol, dodecanethiol and octadecanethiol are bonded to electrode surfaces. Electrolytic capacitors were formed on both unmodified and chemically modified electrodes using KCl and H2SO4 as electrolytes. This molecular modification significantly enhances the current levels in cyclic voltammograms, and there is a clear shift in oxidation/reduction peaks of these capacitors with scan rate. The results obey Randles-Sevcik relation, which indicates that there is enhancement of ionic diffusion at the electrode-electrolyte interface. There is a large enhancement in the values of specific capacitance (almost by 104 times) after the chemical modification. These measurements show that Faradaic reactions are responsible for charge storage/discharge process in these capacitors. Hence, the molecularly modified electrodes can be a good choice to increase the specific capacitance.

In situ X-ray near-edge absorption spectroscopy investigation of the state of charge of all-vanadium redox flow batteries.

PubMed

Jia, Chuankun; Liu, Qi; Sun, Cheng-Jun; Yang, Fan; Ren, Yang; Heald, Steve M; Liu, Yadong; Li, Zhe-Fei; Lu, Wenquan; Xie, Jian

2014-10-22

Synchrotron-based in situ X-ray near-edge absorption spectroscopy (XANES) has been used to study the valence state evolution of the vanadium ion for both the catholyte and anolyte in all-vanadium redox flow batteries (VRB) under realistic cycling conditions. The results indicate that, when using the widely used charge-discharge profile during the first charge process (charging the VRB cell to 1.65 V under a constant current mode), the vanadium ion valence did not reach V(V) in the catholyte and did not reach V(II) in the anolyte. Consequently, the state of charge (SOC) for the VRB cell was only 82%, far below the desired 100% SOC. Thus, such incompletely charged mix electrolytes results in not only wasting the electrolytes but also decreasing the cell performance in the following cycles. On the basis of our study, we proposed a new charge-discharge profile (first charged at a constant current mode up to 1.65 V and then continuously charged at a constant voltage mode until the capacity was close to the theoretical value) for the first charge process that achieved 100% SOC after the initial charge process. Utilizing this new charge-discharge profile, the theoretical charge capacity and the full utilization of electrolytes has been achieved, thus having a significant impact on the cost reduction of the electrolytes in VRB.

Annealing Would Improve beta" - Alumina Solid Electrolyte

NASA Technical Reports Server (NTRS)

Williams, Roger; Homer, Margie; Ryan, Margaret; Cortez, Roger; Shields, Virgil; Kisor, Adam

2003-01-01

A pre-operational annealing process is under investigation as a potential means of preventing a sudden reduction of ionic conductivity in a Beta"-alumina solid electrolyte (BASE) during use. On the basis of tests, the sudden reduction of ionic conductivity, followed by a slow recovery, has been found to occur during testing of the solid electrolyte and electrode components of an alkali metal thermal-to-electric converter (AMTEC) cell. At this time, high-temperature tests of limited duration have indicated the superiority of the treated BASE, but reproducible tests over thousands of hours are necessary to confirm that microcracking has been eliminated. The ionic conductivity of the treated BASE is also measured to be higher than untreated BASE at 1,073 K in low-pressure sodium vapor. Microcracking resulting in loss of conductivity was not observed with treated BASE in one high-temperature experiment, but this result must be duplicated over very long testing times to be sure of the effect. Shorter annealing times (10 to 20 hours) were found to result in significantly less loss of mass; it may be necessary for the packed powder mixture to evolve some Na2O before the Na2O can leave the ceramic.

Functionalized graphene hydrogel-based high-performance supercapacitors.

PubMed

Xu, Yuxi; Lin, Zhaoyang; Huang, Xiaoqing; Wang, Yang; Huang, Yu; Duan, Xiangfeng

2013-10-25

Functionalized graphene hydrogels are prepared by a one-step low-temperature reduction process and exhibit ultrahigh specific capacitances and excellent cycling stability in the aqueous electrolyte. Flexible solid-state supercapacitors based on functionalized graphene hydrogels are demonstrated with superior capacitive performances and extraordinary mechanical flexibility. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of DDL processes during electrolytic reduction of Cu(II) in a low oxygen environment.

PubMed

Brosky, Rebekah T; Pamukcu, Sibel

2013-11-15

Heavy metals typically accumulate in reduced bottom sediments after being discharged into waterways by industrial and municipal processes. A laboratory experiment was conducted in order to determine if abundance of clay in the bottom sediments of a Cu-contaminated aqueous ecosystem could enhance electrolytic reduction of the heavy metal. Cu(NO3)2 · 2.5H2O was added to simulate a moderately contaminated system with 650 μg Cu/ml kaolinite clay-water slurry. A constant electrical potential of 1.0 V/cm was applied across platinum wire electrodes inserted into the continuously stirred system for four days while the system ORP(2) was monitored and periodic sub-samples were taken for analysis. The electrical as well as the chemical results indicate that the quantity of Cu(II) being reduced to Cu(I), especially within the aqueous phase, is increased within the first 48 h of experimentation by the presence of kaolinite clay up to 0.05 mg clay/l slurry. Copyright © 2013 Elsevier B.V. All rights reserved.

Apparatus and method for the electrolytic production of metals

DOEpatents

Sadoway, Donald R.

1991-01-01

Improved electrolytic cells and methods for producing metals by electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells and methods, a protective surface layer is formed upon at least one electrode in the electrolytic reduction cell and, optionally, upon the lining of the cell. This protective surface layer comprises a material that, at the operating conditions of the cell: (a) is not substantially reduced by the metal product; (b) is not substantially reactive with the cell electrolyte to form materials that are reactive with the metal product; and, (c) has an electrochemical potential that is more electronegative than that of the compound undergoing electrolysis to produce the metal product of the cell. The protective surface layer can be formed upon an electrode metal layer comprising a material, the oxide of which also satisfies the protective layer selection criteria. The protective layer material can also be used on the surface of a cell lining.

Ultra-thin solid oxide fuel cells: Materials and devices

NASA Astrophysics Data System (ADS)

Kerman, Kian

Solid oxide fuel cells are electrochemical energy conversion devices utilizing solid electrolytes transporting O2- that typically operate in the 800 -- 1000 °C temperature range due to the large activation barrier for ionic transport. Reducing electrolyte thickness or increasing ionic conductivity can enable lower temperature operation for both stationary and portable applications. This thesis is focused on the fabrication of free standing ultrathin (<100 nm) oxide membranes of prototypical O 2- conducting electrolytes, namely Y2O3-doped ZrO2 and Gd2O3-doped CeO2. Fabrication of such membranes requires an understanding of thin plate mechanics coupled with controllable thin film deposition processes. Integration of free standing membranes into proof-of-concept fuel cell devices necessitates ideal electrode assemblies as well as creative processing schemes to experimentally test devices in a high temperature dual environment chamber. We present a simple elastic model to determine stable buckling configurations for free standing oxide membranes. This guides the experimental methodology for Y 2O3-doped ZrO2 film processing, which enables tunable internal stress in the films. Using these criteria, we fabricate robust Y2O3-doped ZrO2 membranes on Si and composite polymeric substrates by semiconductor and micro-machining processes, respectively. Fuel cell devices integrating these membranes with metallic electrodes are demonstrated to operate in the 300 -- 500 °C range, exhibiting record performance at such temperatures. A model combining physical transport of electronic carriers in an insulating film and electrochemical aspects of transport is developed to determine the limits of performance enhancement expected via electrolyte thickness reduction. Free standing oxide heterostructures, i.e. electrolyte membrane and oxide electrodes, are demonstrated. Lastly, using Y2O3-doped ZrO2 and Gd2O 3-doped CeO2, novel electrolyte fabrication schemes are explored to develop oxide alloys and nanoscale compositionally graded membranes that are thermomechanically robust and provide added interfacial functionality. The work in this thesis advances experimental state-of-the-art with respect to solid oxide fuel cell operation temperature, provides fundamental boundaries expected for ultrathin electrolytes, develops the ability to integrate highly dissimilar material (such as oxide-polymer) heterostructures, and introduces nanoscale compositionally graded electrolyte membranes that can lead to monolithic materials having multiple functionalities.

Evaluation of selected chemical processes for production of low-cost silicon. Quarterly progress report, 15 Dec 1975--31 Mar 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blocher, J.M. Jr; Browning, M.F.; Wilson, W.J.

1976-04-08

Plant construction costs and manufacturing costs were estimmated for the production of solar-grade silicon by the reduction of silicon tetrachloride in a fluidized bed of seed particles, and several modifications of the iodide process using either thermal decomposition on heated filaments (rods) or hydrogen reduction in a fluidized bed of seed particles. Energy consumption data for the zinc reduction process and each of the iodide process options are given and all appear to be acceptable from the standpoint of energy pay back. Information is presented on the experimental zinc reduction of SiCl4 and electrolytic recovery of zinc from ZnCl2. Allmore » of the experimental work performed thus far has supported the initial assumption as to technical feasibility of producing semiconductor silicon by the zinc reduction or iodide processes proposed. The results of a more thorough thermodynamic evaluation of the iodination of silicon oxide/carbon mixtures are presented which explain apparent inconsistencies in an earlier cursory examination of the system.« less

The aluminum smelting process.

PubMed

Kvande, Halvor

2014-05-01

This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development.

The Aluminum Smelting Process

PubMed Central

2014-01-01

This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development. PMID:24806722

Gas phase recovery of hydrogen sulfide contaminated polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Kakati, Biraj Kumar; Kucernak, Anthony R. J.

2014-04-01

The effect of hydrogen sulfide (H2S) on the anode of a polymer electrolyte membrane fuel cell (PEMFC) and the gas phase recovery of the contaminated PEMFC using ozone (O3) were studied. Experiments were performed on fuel cell electrodes both in an aqueous electrolyte and within an operating fuel cell. The ex-situ analyses of a fresh electrode; a H2S contaminated electrode (23 μmolH2S cm-2); and the contaminated electrode cleaned with O3 shows that all sulfide can be removed within 900 s at room temperature. Online gas analysis of the recovery process confirms the recovery time required as around 720 s. Similarly, performance studies of an H2S contaminated PEMFC shows that complete rejuvenation occurs following 600-900 s O3 treatment at room temperature. The cleaning process involves both electrochemical oxidation (facilitated by the high equilibrium potential of the O3 reduction process) and direct chemical oxidation of the contaminant. The O3 cleaning process is more efficient than the external polarization of the single cell at 1.6 V. Application of O3 at room temperature limits the amount of carbon corrosion. Room temperature O3 treatment of poisoned fuel cell stacks may offer an efficient and quick remediation method to recover otherwise inoperable systems.

Reaction mechanisms for the limited reversibility of Li-O 2 chemistry in organic carbonate electrolytes

NASA Astrophysics Data System (ADS)

Xu, Wu; Xu, Kang; Viswanathan, Vilayanur V.; Towne, Silas A.; Hardy, John S.; Xiao, Jie; Nie, Zimin; Hu, Dehong; Wang, Deyu; Zhang, Ji-Guang

The Li-O 2 chemistry in nonaqueous liquid carbonate electrolytes and the underlying reason for its limited reversibility was systematically investigated. X-ray diffraction data showed that regardless of discharge depth lithium alkylcarbonates (lithium propylenedicarbonate (LPDC), or lithium ethylenedicarbonate (LEDC), with other related derivatives) and lithium carbonate (Li 2CO 3) are constantly the main discharge products, while lithium peroxide (Li 2O 2) or lithium oxide (Li 2O) is hardly detected. These lithium alkylcarbonates are generated from the reductive decomposition of the corresponding carbonate solvents initiated by the attack of superoxide radical anions. More significantly, in situ gas chromatography/mass spectroscopy analysis revealed that Li 2CO 3 and Li 2O cannot be oxidized even when charged to 4.6 V vs. Li/Li +, while LPDC, LEDC and Li 2O 2 are readily oxidized, with CO 2 and CO released from LPDC and LEDC and O 2 evolved from Li 2O 2. Therefore, the apparent reversibility of Li-O 2 chemistry in an organic carbonate-based electrolyte is actually an unsustainable process that consists of (1) the formation of lithium alkylcarbonates through the reductive decomposition of carbonate solvents during discharging and (2) the subsequent oxidation of these same alkylcarbonates during charging. Therefore, a stable electrolyte that does not lead to an irreversible by-product formation during discharging and charging is necessary for truly rechargeable Li-O 2 batteries.

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

DOEpatents

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.

Investigating Electrochemical Processes in Secondary Batteries

NASA Astrophysics Data System (ADS)

Cama, Christina A.

For the past twenty-six years, the lithium-ion battery has been the most popular recharge- able battery for portable devices and electric vehicles. Despite its success, the energy storage capability of lithium-ion batteries (LIBs) is significantly limited by both the electrodes and electrolytes employed. Typical LIBs rely on intercalation-type electrodes, that are not capable of storing more than 1 Li+ per formula unit. The energy storage capability of LIBs can be improved through the application of conversion-type materials and beyond lithium chemistries. This research involves multiple projects which explore the electrochemistry of conversion electrodes, magnesium-ion chemistry, and lithium-sulfur chemistry. Application of conversion-electrodes like copper ferrite, CuFe2O4, and magnetite, Fe3O4, are capable of lithium storage over five times greater than that achieved by electrodes used in commercial LIBs. The drawback to utilizing the conversion mechanism is that significant energy storage capability is lost during charge. In this research, X- ray characterization methods, including X-ray Diffraction (XRD) and X-ray Absorption Spectroscopy (XAS) are used to elucidate the lithiation and delithiation mechanism for CuFe2O4 and to understand the source of the irreversibility. These experiments provide significant insight into the reduction processes and cation migration within the structure. During lithiation, CuFe2O4 undergoes a three-step reduction mechanism involving (1) lithiation of CuFe2O4, (2) extrusion of copper metal nanoparticles and formation of rock- salt LiFeO2, followed by the (3) formation of iron metal nanoparticles. Upon delithiation, XAS spectra clearly demonstrate the feasibility of Fe0 oxidation to a rock-salt iron oxide; however, Cu0 oxidation is not observed. Additional experiments explored the kinetic limitations of lithiating Fe3O4 nanoparticles, with different crystallite sizes. The experiments demonstrate that the kinetics of the lithiation mechanism are influenced by the electroactive material’s agglomerate and crystallite size. The rate of lithiation involving small crystallites is dependent on diffusion within the agglomerates; however, as the crystallite size increases, the lithiation rate is inhibited by diffusion within both the agglomerate and the crystallite. Battery chemistries beyond lithium can also lead to energy storage capabilities an order of magnitude higher than LIBs. Both magnesium-ion and lithium-sulfur battery chemistries are investigated in this dissertation. The properties of ionic liquid electrolytes are explored as safer alternatives to harmful Grignard-reagent electrolytes commonly used for magnesium chemistries. Electrochemical evaluation of the ionic liquid electrolytes found that although better conductivity can be achieved with unsaturated electrolytes like imidizolium based electrolytes, greater oxidative voltages are possible with saturated electrolytes like the piperidinium and pyridinium based electrolytes. The higher oxidative voltage is a promising attribute for high voltage applications. Cathode additives, including FeS2 and microporous carbon, are studied to inhibit polysulfide dissolution within the electrolyte of Li|S batteries. Although FeS2 exhibited promising electrochemistry as its own cathode, it was found to be an ineffective additive within sulfur cathodes. Instead, the properties of microporous carbons are explored to identify an appropriate carbon additive to both increase conductivity and impede polysulfide dissolution. A wood based carbon exhibited high capacity and long cycle life at low rate compared to conventional microporous carbons. As a whole, this research has provided valuable insight into the electrochemical processes taking place within a battery, as well as the factors which affect these processes. Electrochemical, spectroscopic, and various scattering methods are used to probe processes which span from the reactions occurring within the electrode to the redox reactions which define the voltage limitations of the electrolyte. These studies demonstrate the impact of each battery component on the overall electrochemical performance and provide fundamental insight into battery operation.

Electrochemistry-Assisted Top-Down Characterization of Disulfide-Containing Proteins

PubMed Central

Zhang, Yun; Cui, Weidong; Zhang, Hao; Dewald, Howard D.; Chen, Hao

2013-01-01

Covalent disulfide bond linkage in a protein represents an important challenge for mass spectrometry (MS)-based top-down protein structure analysis as it reduces the backbone cleavage efficiency for MS/MS dissociation. This study presents a strategy for solving this critical issue via integrating electrochemistry (EC) online with top-down MS approach. In this approach, proteins undergo electrolytic reduction in an electrochemical cell to break disulfide bonds and then online ionized into gaseous ions for analysis by electron-capture dissociation (ECD) and collision-induced dissociation (CID). The electrochemical reduction of proteins allows to remove disulfide bond constraints and also leads to increased charge numbers of the resulting protein ions. As a result, sequence coverage was significantly enhanced, as exemplified by β-lactoglobulin A (24 vs. 73 backbone cleavages before and after electrolytic reduction, respectively) and lysozyme (5 vs. 66 backbone cleavages before and after electrolytic reduction, respectively). This methodology is fast and does not need chemical reductants, which would have an important impact in high-throughput proteomics research. PMID:22448817

Electrochemistry-assisted top-down characterization of disulfide-containing proteins.

PubMed

Zhang, Yun; Cui, Weidong; Zhang, Hao; Dewald, Howard D; Chen, Hao

2012-04-17

Covalent disulfide bond linkage in a protein represents an important challenge for mass spectrometry (MS)-based top-down protein structure analysis as it reduces the backbone cleavage efficiency for MS/MS dissociation. This study presents a strategy for solving this critical issue via integrating electrochemistry (EC) online with a top-down MS approach. In this approach, proteins undergo electrolytic reduction in an electrochemical cell to break disulfide bonds and then undergo online ionization into gaseous ions for analysis by electron-capture dissociation (ECD) and collision-induced dissociation (CID). The electrochemical reduction of proteins allows one to remove disulfide bond constraints and also leads to increased charge numbers of the resulting protein ions. As a result, sequence coverage was significantly enhanced, as exemplified by β-lactoglobulin A (24 vs 75 backbone cleavages before and after electrolytic reduction, respectively) and lysozyme (5 vs 66 backbone cleavages before and after electrolytic reduction, respectively). This methodology is fast and does not need chemical reductants, which would have an important impact in high-throughput proteomics research.

The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiang, Hongfa; Mei, Donghai; Yan, Pengfei

2015-09-10

Propylene carbonate (PC) is seldom used in lithium-ion batteries (LIBs) due to its sustained co-intercalation into graphene structure and the eventual graphite exfoliation, despite potential advantages it brings, such as wider liquid range and lower cost. Here we discover that cesium cation (Cs+), originally used to suppress dendrite growth of Li metal anode, directs the formation of solid electrolyte interphase (SEI) on graphitic anode in PC-rich electrolytes through preferential solvation. Effective suppression of PC-decomposition and graphite-exfoliation was achieved when the ratio of ethylene carbonate (EC)/PC in electrolytes was so adjusted that the reductive decomposition of Cs+-(EC)m (1≤m≤2) complex precedes thatmore » of Li+-(PC)n (3≤n≤5). The interphase directed by Cs+ is stable, ultrathin and compact, leading to significant improvements in LIB performances. In a broader context, the accurate tailoring of SEI chemical composition by introducing a new solvation center represents a fundamental breakthrough in manipulating interfacial reactions processes that once were elusive.« less

Electrolytic Reduction of Titania Slag in Molten Calcium Chloride Bath

NASA Astrophysics Data System (ADS)

Mohanty, Jayashree

2012-05-01

Ferro-titanium is prepared by direct electrolytic reduction of titania-rich slag obtained from plasma smelting of ilmenite in molten CaCl2. The product after electro-reduction is characterized by x-ray diffraction, scanning electron microscopy, and electron probe microanalysis. The electrolysis is carried out at a cell voltage of 3.0 V, taking graphite as the electrolysis cell as well as the anode, and a titania-rich slag piece wrapped by a nichrome wire is used as the cathode.

Magnesia-stabilised zirconia solid electrolyte assisted electrochemical investigation of iron ions in a SiO2-CaO-MgO-Al2O3 molten slag at 1723 K.

PubMed

Gao, Yunming; Yang, Chuanghuang; Zhang, Canlei; Qin, Qingwei; Chen, George Z

2017-06-21

Production of metallic iron through molten oxide electrolysis using inert electrodes is an alternative route for fast ironmaking without CO 2 emissions. The fact that many inorganic oxides melt at ultrahigh temperatures (>1500 K) challenges conventional electro-analytical techniques used in aqueous, organic and molten salt electrolytes. However, in order to design a feasible and effective electrolytic process, it is necessary to best understand the electrochemical properties of iron ions in molten oxide electrolytes. In this work, a magnesia-stabilised zirconia (MSZ) tube with a closed end was used to construct an integrated three-electrode cell with a "MSZ|Pt|O 2 (air)" assembly functioning as the solid electrolyte, the reference electrode and also the counter electrode. Electrochemical reduction of iron ions was systematically investigated on an iridium (Ir) wire working electrode in a SiO 2 -CaO-MgO-Al 2 O 3 molten slag at 1723 K by cyclic voltammetry (CV), square wave voltammetry (SWV), chronopotentiometry (CP) and potentiostatic electrolysis (PE). The results show that the electroreduction of the Fe 2+ ion to Fe on the Ir electrode in the molten slag follows a single two-electron transfer step, and the rate of the process is diffusion controlled. The peak current on the obtained CVs is proportional to the concentration of the Fe 2+ ion in the molten slag and the square root of scan rate. The diffusion coefficient of Fe 2+ ions in the molten slag containing 5 wt% FeO at 1723 K was derived to be (3.43 ± 0.06) × 10 -6 cm 2 s -1 from CP analysis. However, a couple of subsequent processes, i.e. alloy formation on the Ir electrode surface and interdiffusion, were found to affect the kinetics of iron deposition. An ECC mechanism is proposed to account for the CV observations. The findings from this work confirm that zirconia-based solid electrolytes can play an important role in electrochemical fundamental research in high temperature molten slag electrolytes.

Cost analysis of oxygen recovery systems

NASA Technical Reports Server (NTRS)

Yakut, M. M.

1973-01-01

Report is made of the cost analysis of four leading oxygen recovery subsystems which include two carbon dioxide reduction subsystems and two water electrolysis subsystems, namely, the solid polymer electrolyte and the circulating KOH electrolyte. The four oxygen recovery systems were quantitatively evaluated. System characteristics, including process flows, performance, and physical characteristics were also analyzed. Additionally, the status of development of each of the systems considered and the required advance technology efforts required to bring conceptual and/or pre-prototype hardware to an operational prototype status were defined. Intimate knowledge of the operations, development status, and capabilities of the systems to meet space mission requirements were found to be essential in establishing the cost estimating relationships for advanced life support systems.

Hurdles to organic quinone flow cells. Electrode passivation by quinone reduction in acetonitrile Li electrolytes

NASA Astrophysics Data System (ADS)

Rueda-García, D.; Dubal, D. P.; Huguenin, F.; Gómez-Romero, P.

2017-05-01

The uses of quinones in Redox Flow Batteries (RFBs) has been mainly circumscribed to aqueous solutions (of derivatives with polar groups) despite a larger solubility and wider electrochemical window provided by organic media. The redox mechanism of quinones in protic media is simpler and better known than in aprotic media, where radical species are involved. This paper reports the behaviour of methyl-p-benzoquinone (MBQ) under electrochemical reduction conditions in a LiClO4sbnd CH3CN electrolyte and various working electrodes. We detected the reversible generation of a bright green coating on the working electrode and the subsequent formation of a polymer (the nature of which depends on the presence or absence of oxygen). These coatings prevent the regular redox process of methyl-p-benzoquinone from taking place on the surface of the electrode and is generated regardless of the electrode material used or the presence of O2 in solution. In addition to MBQ, the green passivating layer was also found for less sterically hindered quinones such as p-benzoquinone or 1,4-naphthoquinone, but not for anthraquinone. We have also shown the central role of Li+ in the formation of this green layer. This work provides important guidelines for the final use of quinones in RFBs with organic electrolytes.

Electrochemical Reduction of Oxygen in Aprotic Ionic Liquids Containing Metal Cations: A Case Study on the Na-O2 system.

PubMed

Azaceta, Eneko; Lutz, Lukas; Grimaud, Alexis; Vicent-Luna, Jose Manuel; Hamad, Said; Yate, Luis; Cabañero, German; Grande, Hans-Jurgen; Anta, Juan A; Tarascon, Jean-Marie; Tena-Zaera, Ramon

2017-04-10

Metal-air batteries are intensively studied because of their high theoretical energy-storage capability. However, the fundamental science of electrodes, electrolytes, and reaction products still needs to be better understood. In this work, the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) was chosen to study the influence of a wide range of metal cations (M n+ ) on the electrochemical behavior of oxygen. The relevance of the theory of Lewis hard and soft acids and bases to predict satisfactorily the reduction potential of oxygen in electrolytes containing metal cations is demonstrated. Systems with soft and intermediate M n+ acidity are shown to facilitate oxygen reduction and metal oxide formation, whereas oxygen reduction is hampered by hard acid cations such as sodium and lithium. Furthermore, DFT calculations on the energy of formation of the resulting metal oxides rationalize the effect of M n+ on oxygen reduction. A case study on the Na-O 2 system is described in detail. Among other things, the Na + concentration of the electrolyte is shown to control the electrochemical pathway (solution precipitation vs. surface deposition) by which the discharge product grows. All in all, fundamental insights for the design of advanced electrolytes for metal-air batteries, and Na-air batteries in particular, are provided. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The kinetics of ulvoespinel reduction - Synthetic study and applications to lunar rocks.

NASA Technical Reports Server (NTRS)

Mccallister, R. H.; Taylor, L. A.

1973-01-01

The kinetics of Fe2TiO4 reduction to FeTiO3 + Fe were studied using CO-CO2 gas mixtures with fO2 measured by a solid ceramic (calcia-zirconia) oxygen electrolyte cell. Isothermal rate studies at 900 C suggest that the mechanism of Fe2TiO4 reduction is one of nucleation and growth, where the growth stage may be controlled by the diffusion of the reactant through the product layer or volume diffusion. The activation energy for the growth stage of the process was determined to be 46 plus or minus 4 kcal/mole.

Electrochemical Capture and Release of CO2 in Aqueous Electrolytes Using an Organic Semiconductor Electrode

PubMed Central

2017-01-01

Developing efficient methods for capture and controlled release of carbon dioxide is crucial to any carbon capture and utilization technology. Herein we present an approach using an organic semiconductor electrode to electrochemically capture dissolved CO2 in aqueous electrolytes. The process relies on electrochemical reduction of a thin film of a naphthalene bisimide derivative, 2,7-bis(4-(2-(2-ethylhexyl)thiazol-4-yl)phenyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (NBIT). This molecule is specifically tailored to afford one-electron reversible and one-electron quasi-reversible reduction in aqueous conditions while not dissolving or degrading. The reduced NBIT reacts with CO2 to form a stable semicarbonate salt, which can be subsequently oxidized electrochemically to release CO2. The semicarbonate structure is confirmed by in situ IR spectroelectrochemistry. This process of capturing and releasing carbon dioxide can be realized in an oxygen-free environment under ambient pressure and temperature, with uptake efficiency for CO2 capture of ∼2.3 mmol g–1. This is on par with the best solution-phase amine chemical capture technologies available today. PMID:28378994

Influence of ultrasound power and frequency upon corrosion kinetics of zinc in saline media.

PubMed

Doche, M-L; Hihn, J-Y; Mandroyan, A; Viennet, R; Touyeras, F

2003-10-01

This paper is devoted to zinc corrosion and oxidation mechanism in an ultrasonically stirred aerated sodium sulfate electrolyte. It follows a previous study devoted to the influence of 20 kHz ultrasound upon zinc corrosion in NaOH electrolytes [Ultrason. Sonochemis. 8 (2001) 291]. In the present work, various ultrasound regimes were applied by changing the transmitted power and the wave frequency (20 and 40 kHz). Unlike NaOH electrolyte which turns the zinc electrode into a passive state, Na2SO4 saline media induces soft corrosion conditions. This allows a study of the combined effects of ultrasonically modified hydrodynamic and mechanical damage (cavitation) upon the zinc corrosion process. A series of initial experiments were carried out so as to determine the transmitted power and to characterize mass transfer distribution in the electrochemical cell. Zinc corrosion and oxidation process were subsequently studied with respect to the vibrating parameters. When exposed to a 20 kHz ultrasonic field, and provided that the electrode is situated at a maximum mass transfer point, the corrosion rate reaches values six to eight times greater than in silent conditions. The zinc oxidation reaction, in the absence of competitive reduction reactions, is also activated by ultrasound (20 and 40 kHz) but probably through a different process of surface activation.

Practical high temperature (80 °C) storage study of industrially manufactured Li-ion batteries with varying electrolytes

NASA Astrophysics Data System (ADS)

Genieser, R.; Loveridge, M.; Bhagat, R.

2018-05-01

A previous study is focused on high temperature cycling of industrially manufactured Li-ion pouch cells (NMC-111/Graphite) with different electrolytes at 80 °C [JPS 373 (2018) 172-183]. Within this article the same test set-up is used, with cells stored for 30 days at different open circuit potentials and various electrolytes instead of electrochemical cycling. The most pronounced cell degradation (capacity fade and resistance increase) happens at high potentials. However appropriate electrolyte formulations are able to suppress ageing conditions by forming passivating surface films on both electrodes. Compared with electrochemical cycling at 80 °C, cells with enhanced electrolytes only show a slight resistance increase during storage and the capacity fade is much lower. Additionally it is shown for the first time, that the resistance is decreasing and capacity is regained once these cells are cycled again at room temperature. This is not the case for electrolytes without additives or just vinylene carbonate (VC) as an additive. It is further shown that the resistance increase of cells with the other electrolytes is accompanied by a reduction of the cell volume during further cycling. This behaviour is likely related to the reduction of CO2 at the anode to form additional SEI layer components.

Durable rechargeable zinc-air batteries with neutral electrolyte and manganese oxide catalyst

NASA Astrophysics Data System (ADS)

Sumboja, Afriyanti; Ge, Xiaoming; Zheng, Guangyuan; Goh, F. W. Thomas; Hor, T. S. Andy; Zong, Yun; Liu, Zhaolin

2016-11-01

Neutral chloride-based electrolyte and directly grown manganese oxide on carbon paper are used as the electrolyte and air cathode respectively for rechargeable Zn-air batteries. Oxygen reduction and oxygen evolution reactions on manganese oxide show dependence of activities on the pH of the electrolyte. Zn-air batteries with chloride-based electrolyte and manganese oxide catalyst exhibit satisfactory voltage profile (discharge and charge voltage of 1 and 2 V at 1 mA cm-2) and excellent cycling stability (≈90 days of continuous cycle test), which is attributed to the reduced carbon corrosion on the air cathode and decreased carbonation in neutral electrolyte. This work describes a robust electrolyte system that improves the cycle life of rechargeable Zn-air batteries.

Shedding Light on the Oxygen Reduction Reaction Mechanism in Ether-Based Electrolyte Solutions: A Study Using Operando UV-Vis Spectroscopy.

PubMed

Hirshberg, Daniel; Sharon, Daniel; Afri, Michal; Lavi, Ronit; Frimer, Aryeh A; Metoki, Noa; Eliaz, Noam; Kwak, Won-Jin; Sun, Yang-Kook; Aurbach, Doron

2018-04-04

Using UV-vis spectroscopy in conjunction with various electrochemical techniques, we have developed a new effective operando methodology for investigating the oxygen reduction reactions (ORRs) and their mechanisms in nonaqueous solutions. We can follow the in situ formation and presence of superoxide moieties during ORR as a function of solvent, cations, anions, and additives in the solution. Thus, using operando UV-vis spectroscopy, we found evidence for the formation of superoxide radical anions during oxygen reduction in LiTFSI/diglyme electrolyte solutions. Nitro blue tetrazolium (NBT) was used to indicate the presence of superoxide moieties based on its unique spectral response. Indeed, the spectral response of NBT containing solutions undergoing ORR could provide a direct indication for the level of association of the Li cations with the electrolyte anions.

Autogenous electrolyte, non-pyrolytically produced solid capacitor structure

DOEpatents

Sharp, Donald J.; Armstrong, Pamela S.; Panitz, Janda Kirk G.

1998-01-01

A solid electrolytic capacitor having a solid electrolyte comprising manganese dioxide dispersed in an aromatic polyamide capable of further cure to form polyimide linkages, the solid electrolyte being disposed between a first electrode made of valve metal covered by an anodic oxide film and a second electrode opposite the first electrode. The electrolyte autogenously produces water, oxygen, and hydroxyl groups which act as healing substances and is not itself produced pyrolytically. Reduction of the manganese dioxide and the water molecules released by formation of imide linkages result in substantially improved self-healing of anodic dielectric layer defects.

Autogenous electrolyte, non-pyrolytically produced solid capacitor structure

DOEpatents

Sharp, D.J.; Armstrong, P.S.; Panitz, J.K.G.

1998-03-17

A solid electrolytic capacitor is described having a solid electrolyte comprising manganese dioxide dispersed in an aromatic polyamide capable of further cure to form polyimide linkages, the solid electrolyte being disposed between a first electrode made of valve metal covered by an anodic oxide film and a second electrode opposite the first electrode. The electrolyte autogenously produces water, oxygen, and hydroxyl groups which act as healing substances and is not itself produced pyrolytically. Reduction of the manganese dioxide and the water molecules released by formation of imide linkages result in substantially improved self-healing of anodic dielectric layer defects. 2 figs.

Composition and particle size of electrolytic copper powders prepared in water-containing dimethyl sulfoxide electrolytes

NASA Astrophysics Data System (ADS)

Mamyrbekova, Aigul'; Abzhalov, B. S.; Mamyrbekova, Aizhan

2017-07-01

The possibility of the electroprecipitation of copper powder via the cathodic reduction of an electrolyte solution containing copper(II) nitrate trihydrate and dimethyl sulfoxide (DMSO) is shown. The effect electrolysis conditions (current density, concentration and temperature of electrolyte) have on the dimensional characteristics of copper powder is studied. The size and shape of the particles of the powders were determined by means of electron microscopy; the qualitative composition of the powders, with X-ray diffraction.

A p-nitroaniline redox-active solid-state electrolyte for battery-like electrochemical capacitive energy storage combined with an asymmetric supercapacitor based on metal oxide functionalized β-polytype porous silicon carbide electrodes.

PubMed

Kim, Myeongjin; Yoo, Jeeyoung; Kim, Jooheon

2017-05-23

A unique redox active flexible solid-state asymmetric supercapacitor with ultra-high capacitance and energy density was fabricated using a composite comprising MgCo 2 O 4 nanoneedles and micro and mesoporous silicon carbide flakes (SiCF) (SiCF/MgCo 2 O 4 ) as the positive electrode material. Due to the synergistic effect of the two materials, this hybrid electrode has a high specific capacitance of 516.7 F g -1 at a scan rate of 5 mV s -1 in a 1 M KOH aqueous electrolyte. To obtain a reasonable matching of positive and negative electrode pairs, a composite of Fe 3 O 4 nanoparticles and SiCF (SiCF/Fe 3 O 4 ) was synthesized for use as a negative electrode material, which shows a high capacitance of 423.2 F g -1 at a scan rate of 5 mV s -1 . Therefore, by pairing the SiCF/MgCo 2 O 4 positive electrode and the SiCF/Fe 3 O 4 negative electrode with a redox active quasi-solid-state PVA-KOH-p-nitroaniline (PVA-KOH-PNA) gel electrolyte, a novel solid-state asymmetric supercapacitor device was assembled. Because of the synergistic effect between the highly porous SiCF and the vigorous redox-reaction of metal oxides, the hybrid nanostructure electrodes exhibited outstanding charge storage and transport. In addition, the redox active PVA-KOH-PNA electrolyte adds additional pseudocapacitance, which arises from the nitro-reduction and oxidation and reduction process of the reduction product of p-phenylenediamine, resulting in an enhancement of the capacitance (a specific capacitance of 161.77 F g -1 at a scan rate of 5 mV s -1 ) and energy density (maximum energy density of 72.79 Wh kg -1 at a power density of 727.96 W kg -1 ).

Electrodeposition mechanism of quaternary compounds Cu2ZnSnS4: Effect of the additives

NASA Astrophysics Data System (ADS)

Tang, Aiyue; Li, Zhilin; Wang, Feng; Dou, Meiling; Liu, Jingjun; Ji, Jing; Song, Ye

2018-01-01

The electrodeposition mechanism of pure phase Cu2ZnSnS4 (CZTS) thin film with subsequent annealing was investigated in detail. An electrolyte design principle of quaternary compounds was proposed. The complex ions of Cu(H2C6H5O7)+, Cu2(C6H5O7)+, Zn(C4H5O6)+, Sn(H2C6H5O7)+ and Sn2(C6H5O7)+, which influenced the reduction process and played important roles in co-deposition, were identified by UV spectra. Electrochemical studies indicated that trisodium citrate and tartaric acid could narrow the co-deposition potential range of the four elements to -0.8 V to -1.2 V (vs. SCE). The cause was the synergetic effect that trisodium citrate inhibited the reduction of Cu2+ and Sn2+ and tartaric acid promoted the reduction of Zn2+. The reduction of S2O32- was mainly attributed to the induction effect of the metallic ions, and the H+ dissociated from tartaric acid could also promote the cathode process of S2O32-. The reaction mechanism could be summarized as the following steps: (I) Cu(H2C6H5O7)+, Cu2(C6H5O7)+ → Cu, Sn(H2C6H5O7)+, Sn2(C6H5O7)+ → Sn, Zn(C4H5O6)+ → Zn; (II) the desorption of (H2C6H5O7)- and (C6H5O7)-, and the reduction of S2O32- induced by metallic ions and H+. The mechanism studies provided a path of electrolyte design for multicomponent compounds.

Fabrication and Performance of Zirconia Electrolysis Cells for Cabon Dioxide Reduction for Mars In Situ Resource Utilization Applications

NASA Technical Reports Server (NTRS)

Minh, N. Q.; Chung, B. W.; Doshi, R.; Lear, G. R.; Montgomery, K.; Ong, E. T.

1999-01-01

Use of the Martian atmosphere (95% CO2) to produce oxygen (for propellant and life support) can significantly lower the required launch mass and dramatically reduce the total cost for Mars missions. Zirconia electrolysis cells are one of the technologies being considered for oxygen generation from carbon dioxide in Mars In Situ Resource Utilization (ISRU) production plants. The attractive features of the zirconia cell for this application include simple operation and lightweight, low volume system. A zirconia electrolysis cell is an all-solid state device, based on oxygen-ion conducting zirconia electrolytes, that electrochemically reduces carbon dioxide to oxygen and carbon monoxide. The cell consists of two porous electrodes (the anode and cathode) separated by a dense zirconia electrolyte. Typical zirconia cells contain an electrolyte layer which is 200 to 400 micrometer thick. The electrical conductivity requirement for the electrolyte necessitates an operating temperature of 9000 to 10000C. Recently, the fabrication of zirconia cells by the tape calendering has been evaluated. This fabrication process provides a simple means of making cells having very thin electrolytes (5 to 30 micrometers). Thin zirconia electrolytes reduce cell ohmic losses, permitting efficient operation at lower temperatures (8000C or below). Thus, tape-calendered cells provides not only the potential of low temperature operation but also the flexibility in operating temperatures. This paper describes the fabrication of zirconia cells by the tape calendering method and discusses the performance results obtained to date.

Safeguard monitoring of direct electrolytic reduction

NASA Astrophysics Data System (ADS)

Jurovitzki, Abraham L.

Nuclear power is regaining global prominence as a sustainable energy source as the world faces the consequences of depending on limited fossil based, CO2 emitting fuels. A key component to achieving this sustainability is to implement a closed nuclear fuel cycle. Without achieving this goal, a relatively small fraction of the energy value in nuclear fuel is actually utilized. This involves recycling of spent nuclear fuel (SNF)---separating fissile actinides from waste products and using them to fabricate fresh fuel. Pyroprocessing is a viable option being developed for this purpose with a host of benefits compared to other recycling options, such as PUREX. Notably, pyroprocessing is ill suited to separate pure plutonium from spent fuel and thus has non-proliferation benefits. Pyroprocessing involves high temperature electrochemical and chemical processing of SNF in a molten salt electrolyte. During this batch process, several intermediate and final streams are produced that contain radioactive material. While pyroprocessing is ineffective at separating pure plutonium, there are various process misuse scenarios that could result in diversion of impure plutonium into one or more of these streams. This is a proliferation risk that should be addressed with innovative safeguards technology. One approach to meeting this challenge is to develop real time monitoring techniques that can be implemented in the hot cells and coupled with the various unit operations involved with pyroprocessing. Current state of the art monitoring techniques involve external chemical assaying which requires sample removal from these unit operations. These methods do not meet International Atomic Energy Agency's (IAEA) timeliness requirements. In this work, a number of monitoring techniques were assessed for their viability as online monitoring tools. A hypothetical diversion scenario for the direct electrolytic reduction process was experimentally verified (using Nd2O3 as a surrogate for PuO2). Electrochemical analysis was demonstrated to be effective at detecting even very dilute concentrations of actinides as evidence for a diversion attempt.

Electrochemically induced dual reactive barriers for transformation of TCE and mixture of contaminants in groundwater.

PubMed

Mao, Xuhui; Yuan, Songhu; Fallahpour, Noushin; Ciblak, Ali; Howard, Joniqua; Padilla, Ingrid; Loch-Caruso, Rita; Alshawabkeh, Akram N

2012-11-06

A novel reactive electrochemical flow system consisting of an iron anode and a porous cathode is proposed for the remediation of mixture of contaminants in groundwater. The system consists of a series of sequentially arranged electrodes, a perforated iron anode, a porous copper cathode followed by a mesh-type mixed metal oxide anode. The iron anode generates ferrous species and a chemically reducing environment, the porous cathode provides a reactive electrochemically reducing barrier, and the inert anode provides protons and oxygen to neutralize the system. The redox conditions of the electrolyte flowing through this system can be regulated by controlling the distribution of the electric current. Column experiments are conducted to evaluate the process and study the variables. The electrochemical reduction on a copper foam cathode produced an electrode-based reductive potential capable of reducing TCE and nitrate. Rational electrodes arrangement, longer residence time of electrolytes and higher surface area of the foam electrode improve the reductive transformation of TCE. More than 82.2% TCE removal efficiency is achieved for the case of low influent concentration (<7.5 mg/L) and high current (>45 mA). The ferrous species produced from the iron anode not only enhance the transformation of TCE on the cathode, but also facilitates transformation of other contaminants including dichromate, selenate and arsenite. Removal efficiencies greater than 80% are achieved for these contaminants in flowing contaminated water. The overall system, comprising the electrode-based and electrolyte-based barriers, can be engineered as a versatile and integrated remedial method for a relatively wide spectrum of contaminants and their mixtures.

Modeling Joule Heating Effect on Lunar O2 Generation via Electrolytic Reduction.

NASA Technical Reports Server (NTRS)

Dominquez, Jesus; Poizeau, Sophie; Sibille, Laurent

2009-01-01

Kennedy Space Center is leading research work on lunar O2 generation via electrolytic reduction of regolith; the metal oxide present in the regolith is dissociated in oxygen anions and metal cations leading to the generation of gaseous oxygen at the anode and liquid metal at the cathode. Electrical resistance of molten regolith is high, leading to heating of the melt when electrical current is applied between the electrodes (Joule heating). The authors have developed a 3D model using a rigorous approach for two coupled physics (thermal and electrical potential) to not only study the effect of Joule heating on temperature distribution throughout the molten regolith but also to evaluate and optimize the design of the electrolytic cells. This paper presents the results of the thermal analysis performed on the model and used to validate the design of the electrolytic cell.

Polymer membrane based electrolytic cell and process for the direct generation of hydrogen peroxide in liquid streams

NASA Technical Reports Server (NTRS)

White, James H. (Inventor); Schwartz, Michael (Inventor); Sammells, Anthony F. (Inventor)

1997-01-01

An electrolytic cell for generating hydrogen peroxide is provided including a cathode containing a catalyst for the reduction of oxygen, and an anode containing a catalyst for the oxidation of water. A polymer membrane, semipermeable to either protons or hydroxide ions is also included and has a first face interfacing to the cathode and a second face interfacing to the anode so that when a stream of water containing dissolved oxygen or oxygen bubbles is passed over the cathode and a stream of water is passed over the anode, and an electric current is passed between the anode and the cathode, hydrogen peroxide is generated at the cathode and oxygen is generated at the anode.

Structural features of the nonionic surfactants stabilizing long-lived bubble nuclei

NASA Technical Reports Server (NTRS)

Darrigo, J. S.

1980-01-01

A study of the effects of various electrolytes and one organic compound on bubble production in agarose gels is presented. Several preparations of ultrapure agarose were compared for 42 electrolytes and phenol to identify trends in bubble formation. The anion and cation sequences of bubble suppression are similar to processes for salting out of nonionic surfactants. The reduction of bubble number by polyvalent ions and 1% phenol suggests that the polar portions of these nonionic surfactants represent amide groups. The evidence for amide groups is consistent with the relative positions of Mg(2+) in all cation sequences; this result makes it unlikely that either linkages contribute to the hydrophilicity of the nonionic surfactants stabilizing bubble nuclei in the different aqueous gels tested.

Tunable Molecular-Scale Materials for Catalyzing the Low-Overpotential Electrochemical Conversion of CO2.

PubMed

Rosen, Brian A; Hod, Idan

2018-04-25

Electrochemical CO 2 reduction provides a clean and viable alternative for mitigating the environmental aspects of global greenhouse gas emissions. To date, the simultaneous goals of CO 2 reduction at high selectivity and activity have yet to be achieved. Here, the importance of engineering both sides of the electrode-electrolyte interface as a rational strategy for achieving this milestone is highlighted. An emphasis is placed on researchers contributing to the design of solid electrodes based on metal-organic frameworks (MOFs) and electrolytes based on room-temperature ionic liquids (RTILs). Future research geared toward optimizing the electrode-electrolyte interface for efficient and selective CO 2 reduction can be achieved by understanding the structure of newly designed RTILs at the electrified interface, as well as structure-activity relationships in highly tunable MOF platforms. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-step electrolytic preparation of Si-Fe alloys as anodes for lithium ion batteries

NASA Astrophysics Data System (ADS)

Wang, Hailong; Sun, Diankun; Song, Qiqi; Xie, Wenqi; Jiang, Xu; Zhang, Bo

2016-06-01

One-step electrolytic formation of uniform crystalline Si-Fe alloy particles was successfully demonstrated in direct electro-reduction of solid mixed oxides of SiO2 and Fe2O3 in molten CaCl2 at 900∘C. Upon constant voltage electrolysis of solid mixed oxides at 2.8V between solid oxide cathode and graphite anode for 5h, electrolytic Si-Fe with the same Si/Fe stoichimetry of the precursory oxides was generated. The firstly generated Fe could function as depolarizers to enhance reduction rate of SiO2, resulting in the enhanced reduction kinetics to the electrolysis of individual SiO2. When evaluated as anode for lithium ion batteries, the prepared SiFe electrode showed a reversible lithium storage capacity as high as 470mAh g-1 after 100 cycles at 200mA g-1, promising application in high-performance lithium ion batteries.

Cosolvent electrolytes for electrochemical devices

DOEpatents

Wessells, Colin Deane; Firouzi, Ali; Motallebi, Shahrokh; Strohband, Sven

2018-01-23

A method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

Cosolvent electrolytes for electrochemical devices

DOEpatents

Wessells, Colin Deane; Firouzi, Ali; Motallebi, Shahrokh; Strohband, Sven

2018-02-13

A system and method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

Cosolvent electrolytes for electrochemical devices

DOEpatents

Wessells, Colin Deane; Firouzi, Ali; Motallebi, Shahrokh; Strohband, Sven

2018-05-15

A system and method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.

Chemical stability of Lithium 2-trifluoromethyl-4,5-dicyanoimidazolide, an electrolyte salt for Li-ion cells

DOE PAGES

Shkrob, Ilya A.; Pupek, Krzysztof Z.; Gilbert, James A.; ...

2016-12-01

Lithium hexafluorophosphate (LiPF 6) is ubiquitous in commercial lithium-ion batteries, but it is hydrolytically unstable and corrosive on electrode surfaces. Using a more stable salt would confer multiple benefits for high-voltage operation, but many such electrolyte systems facilitate anodic dissolution and pitting corrosion of aluminum current collectors that negate their advantages. Lithium 2-trifluoromethyl-4,5-dicyanoimidazolide (LiTDI) is a new salt that was designed specifically for high-voltage cells. In this study we demonstrate that in carbonate electrolytes, LiTDI prevents anodic dissolution of Al current collectors, which places it into a select group of corrosion inhibitors. However, we also demonstrate that LiTDI becomes reducedmore » on lithiated graphite, undergoing sequential defluorination and yielding a thick and resistive solid-electrolyte interphase (SEI), which increases impedance and lowers electrode capacity. The mechanistic causes for this behavior are examined using computational chemistry methods in the light of recent spectroscopic studies. Here, we demonstrate that LiTDI reduction can be prevented by certain electrolyte additives, which include fluoroethylene carbonate, vinylene carbonate and lithium bis(oxalato)borate. This beneficial action is due to preferential reduction of these additives over LiTDI at a higher potential vs. Li/Li +, so the resulting SEI can prevent the direct reduction of LiTDI at lower potentials on the graphite electrode.« less

Ceramic electrolyte coating methods

DOEpatents

Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

2004-10-12

Processes for preparing aqueous suspensions of a nanoscale ceramic electrolyte material such as yttrium-stabilized zirconia. The invention also includes a process for preparing an aqueous coating slurry of a nanoscale ceramic electrolyte material. The invention further includes a process for depositing an aqueous spray coating slurry including a ceramic electrolyte material on pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

Vanadium Flow Battery Electrolyte Synthesis via Chemical Reduction of V2O5 in Aqueous HCl and H2SO4.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Small, Leo J.; Pratt, Harry; Staiger, Chad

We report a simple method to synthesize V 4+ (VO 2+ ) electrolytes as feedstock for all- vanadium redox flow batteries (RFB). By dissolving V 2 O 5 in aqueous HCl and H 2 SO 4 , subsequently adding glycerol as a reducing agent, we have demonstrated an inexpensive route for electrolyte synthesis to concentrations >2.5 M V 4+ (VO 2+ ). Electrochemical analysis and testing of laboratory scale RFB demonstrate improved thermal stability across a wider temperature range (-10-65 degC) for V 4+ (VO 2+ ) electrolytes in HCl compared to in H 2 SO 4 electrolytes.

Electrolytic Production of Ti5Si3/TiC Composites by Solid Oxide Membrane Technology

NASA Astrophysics Data System (ADS)

Zheng, Kai; Zou, Xingli; Xie, Xueliang; Lu, Changyuan; Chen, Chaoyi; Xu, Qian; Lu, Xionggang

2017-12-01

This paper investigated the electrolytic production of Ti5Si3/TiC composites from TiO2/SiO2/C in molten CaCl2. The solid-oxide oxygen-ion-conducting membrane tube filled with carbon-saturated liquid tin was served as the anode, and the pressed spherical TiO2/SiO2/C pellet was used as the cathode. The electrochemical reduction process was carried out at 1273 K and 3.8 V. The characteristics of the obtained cathode products and the reaction mechanism of the electroreduction process were studied by a series of time-dependent electroreduction experiments. It was found that the electroreduction process generally proceeds through the following steps: TiO2/SiO2/C → Ti2O3, CaTiO3, Ca2SiO4, SiC → Ti5Si3, TiC. The morphology observation and the elemental distribution analysis indicate that the reaction routes for Ti5Si3 and TiC products are independent during the electroreduction process.

Electrolytic Production of Ti5Si3/TiC Composites by Solid Oxide Membrane Technology

NASA Astrophysics Data System (ADS)

Zheng, Kai; Zou, Xingli; Xie, Xueliang; Lu, Changyuan; Chen, Chaoyi; Xu, Qian; Lu, Xionggang

2018-02-01

This paper investigated the electrolytic production of Ti5Si3/TiC composites from TiO2/SiO2/C in molten CaCl2. The solid-oxide oxygen-ion-conducting membrane tube filled with carbon-saturated liquid tin was served as the anode, and the pressed spherical TiO2/SiO2/C pellet was used as the cathode. The electrochemical reduction process was carried out at 1273 K and 3.8 V. The characteristics of the obtained cathode products and the reaction mechanism of the electroreduction process were studied by a series of time-dependent electroreduction experiments. It was found that the electroreduction process generally proceeds through the following steps: TiO2/SiO2/C → Ti2O3, CaTiO3, Ca2SiO4, SiC → Ti5Si3, TiC. The morphology observation and the elemental distribution analysis indicate that the reaction routes for Ti5Si3 and TiC products are independent during the electroreduction process.

Specific detection of membrane-toxic substances with a conductivity assay.

PubMed

Eich, J; Dürholt, H; Steger-Hartmann, T; Wagner, E

2000-03-01

A conductivity assay that represents a new biotest able to detect the effects of membrane-toxic compounds, e.g., detergents, organic solvents, and radical formers, on various organisms was previously described and developed. The conductivity assay measures ion leakage from cells, tissues, or whole plant and animal organisms whose membrane systems have been damaged by membrane-toxic compounds. In this study the specificity of the conductivity assay for membrane-toxic compounds was tested by comparing the electrolyte efflux from Elodea canadensis leaves during incubation with a well-known detergent (benzalkonium chloride) using different plant physiological and biochemical techniques (photochemical efficiency, plasmolysis capacity, NBT reduction, and electron microscopy of membranes of E. canadensis leaves). The comparison of the different methods proved that the electrolyte loss during benzalkonium chloride incubation determined in the conductivity assay is due to membrane impairment. The observed electrolyte loss correlated with a reduction of photochemical efficiency and a decrease in both plasmolysis and NBT reduction capacity. Furthermore, a disintegration of the plasmalemma could be seen in the electron micrographs. These results indicate that the measured electrolyte loss in the conductivity assay is a specific effect of membrane-toxic compounds. Copyright 2000 Academic Press.

Curvature in solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Li, Wenxia; Hasinska, Kathy; Seabaugh, Matt; Swartz, Scott; Lannutti, John

At this point in history, curvature is inherent to the laminated components that comprise solid oxide fuel cells (SOFCs). Surprisingly, however, this fact has never been previously quantified in the literature. In addition, potential curvature changes associated with NiO reduction and re-oxidation during operation have not been investigated. In this report, an optical profilometer was employed to non-destructively quantify the surface curvature or cracking behavior observed on a large scale in industrially manufactured cells. This provides insights into the challenges that the component materials face as well as additional appreciation for why, in spite of a concerted effort to commercialize SOFC power generation, all currently manufactured SOFC stacks fail. Our results demonstrate that cracked electrolyte areas (caused by differential sintering) are flatter than uncracked regions. The height of the electrolyte surface ranged from 86 to 289 μm above the baseline following sintering. Reduction typically results in increases in curvature of up to 214 μm. Initial crack density appears to affect curvature evolution during reduction; the higher the crack density, the smaller the curvature increase following reduction at 600 °C. In general, however, we observed that the electrolyte layer is remarkably resistant to further cracking during these typographic changes. Following oxidation at 750 °C, large changes in curvature (up to 280 μm) are noted that appear to be related to the strength of the bond between the electrolyte and the underlying anode.

The oxidation of organic additives in the positive vanadium electrolyte and its effect on the performance of vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Nguyen, Tam D.; Whitehead, Adam; Scherer, Günther G.; Wai, Nyunt; Oo, Moe O.; Bhattarai, Arjun; Chandra, Ghimire P.; Xu, Zhichuan J.

2016-12-01

Despite many desirable properties, the vanadium redox flow battery is limited, in the maximum operation temperature that can be continuously endured, before precipitation begins in the positive electrolyte. Many additives have been proposed to improve the thermal stability of the charged positive electrolyte. However, we have found that the apparent stability, revealed in laboratory testing, is often simply an artifact of the test method and arises from the oxidation of the additive, with corresponding partial reduction of V(V) to V(IV). This does not improve the stability of the electrolyte in an operating system. Here, we examined the oxidation of some typical organic additives with carboxyl, alcohol, and multi-functional groups, in sulfuric acid solutions containing V(V). The UV-vis measurements and titration results showed that many compounds reduced the state-of-charge (SOC) of vanadium electrolyte, for example, by 27.8, 88.5, and 81.9% with the addition of 1%wt of EDTA disodium salt, pyrogallol, and ascorbic acid, respectively. The cell cycling also indicated the effect of organic additives on the cell performance, with significant reduction in the usable charge capacity. In addition, a standard screening method for thermally stable additives was introduced, to quickly screen suitable additives for the positive vanadium electrolyte.

An environmentally compliant cerium-based conversion coating for aluminum protection

NASA Astrophysics Data System (ADS)

Lin, Xuan

Chromate conversion coatings have been extensively used in the aircraft industry for the corrosion protection of aluminum alloys. Unfortunately, hexavalent chromium, which is a primary component in the chromating process, is a confirmed carcinogen. Because of rising remediation and disposal costs caused by increasingly strict regulations, the replacement of the traditional chromate conversion process is becoming a top priority in the metal finishing industry. This research focused on the electrodeposition of cerium-based coatings on 7075-T6 aluminum alloy in an electrolyte containing a cerium salt, an oxidizing agent and an organic solvent. The cerium-rich deposits were characterized by phase composition, oxidation state, coating thickness, surface morphology, deposition mechanism and polarization behavior. Chemical and electrochemical tests were utilized to compare the corrosion resistance between cerium-based coatings and chromate conversion coatings. To characterize and simulate the deposition process, a variety of approaches were utilized to study the oxidation states of cerium in various soluble and precipitated forms as a function of hydrogen peroxide and electrolyte pH. The pH ranges where the oxidation and reduction reactions dominate were determined. Further studies were performed to optimize the corrosion performance of cerium-based coatings and to understand the effects of electrolyte constituents and deposition parameters. The optimum levels for these variables were identified. A patent disclosure on the cerium-based coating process was made to the University of Missouri-Rolla and has now been officially filed with the U.S. Patent Office.

ELECTROLYTIC REDUCTION OF NITRIC ACID SOLUTIONS

DOEpatents

Alter, H.W.; Barney, D.L.

1958-09-30

A process is presented for the treatment of radioactivc waste nitric acid solutions. The nitric acid solution is neutralized with an alkali metal hydroxide in an amount sufficient to precipitate insoluble hydroxides, and after separation of the precipitate the solution is electrolyzed to convert the alkali nitrate formed, to alkali hydroxide, gaseous ammonla and oxygen. The solution is then reusable after reducing the volume by evaporating the water and dissolved ammonia.

Chemical and Electrochemical Processing of Aluminum Dross Using Molten Salts

NASA Astrophysics Data System (ADS)

Yan, Xiao Y.

2008-04-01

A novel molten salt process was investigated, where Al, as metal or contained in Al2O3 and AlN, was recovered from Al dross by chemical or direct electrochemical reduction in electrolytic cells. Electrolysis experiments were carried out under argon at temperatures from 1123 to 1243 K. In order to better understand the reduction behavior, the as-received Al dross was simulated using simplified systems, including pure Al2O3, pure AlN, an Al2O3/AlN binary mixture, and an Al2O3/AlN/Al ternary mixture. The reduction of the as-received dross was also studied experimentally. The studies showed that solid Al2O3 was chemically reduced by the Ca in a Ca-saturated Ca-CaCl2 melt to form Al2Ca or electrochemically reduced to Al-rich Al-Ca alloys and that the Al value in the Al2O3 was easily recovered from the Al drosses. It was found experimentally that solid AlN in the drosses could not be calciothermically reduced to any extent, consistent with thermodynamic evaluations. It was also found that the direct electrochemical reduction of the AlN in the drosses was confined to three phase boundaries (3PBs) between the AlN, the electrolyte, and the current collector and could not be enhanced by using the LiCl-containing chloride melt or the chloride-fluoride melts studied. The presence of Al powder in the Al2O3/AlN mixture facilitated the direct electrochemical reduction of both Al2O3 and AlN. The reduction mechanisms are discussed based upon the present experimental observations. Flow sheets for recovering the metallic Al and the Al in the Al2O3 and AlN from Al dross are finally proposed.

The state of understanding of the lithium-ion-battery graphite solid electrolyte interphase (SEI) and its relationship to formation cycling

DOE PAGES

An, Seong Jin; Li, Jianlin; Daniel, Claus; ...

2016-04-09

An in-depth review is presented on the science of lithium-ion battery (LIB) solid electrolyte interphase (SEI) formation on the graphite anode, including structure, morphology, chemical composition, electrochemistry, formation mechanism, and LIB formation cycling. During initial operation of LIBs, the SEI layer forms on the graphite surfaces, the most commonly used anode material, due to side reactions with the electrolyte solvent/salt at low electro-reduction potentials. It is accepted that the SEI layer is essential to the long-term performance of LIBs, and it also has an impact on its initial capacity loss, self-discharge characteristics, cycle life, rate capability, and safety. While themore » presence of the anode SEI layer is vital, it is difficult to control its formation and growth, as the chemical composition, morphology, and stability depend on several factors. These factors include the type of graphite, electrolyte composition, electrochemical conditions, and cell temperature. Thus, SEI layer formation and electrochemical stability over long-term operation should be a primary topic of future investigation in the development of LIB technology. We review the progression of knowledge gained about the anode SEI, from its discovery in 1979 to the current state of understanding, and covers its formation process, differences in the chemical and structural makeup when cell materials and components are varied, methods of characterization, and associated reactions with the liquid electrolyte phase. It also discusses the relationship of the SEI layer to the LIB formation step, which involves both electrolyte wetting and subsequent slow charge-discharge cycles to grow the SEI.« less

Oxygen Reduction Reaction Activity of Platinum Thin Films with Different Densities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ergul, Busra; Begum, Mahbuba; Kariuki, Nancy

Platinum thin films with different densities were grown on glassy carbon electrodes by high pressure sputtering deposition and evaluated as oxygen reduction reaction catalysts for polymer electrolyte fuel cells using cyclic voltammetry and rotating disk electrode techniques in aqueous perchloric acid electrolyte. The electrochemically active surface area, ORR mass activity (MA) and specific activity (SA) of the thin film electrodes were obtained. MA and SA were found to be higher for low-density films than for high-density film.

DOUBLE-BAKED, SELF-CHANNELLING ELECTRODE

DOEpatents

Piper, R.D.; Leifield, R.F.

1963-03-12

A method is given for making an electrode for use in the electrolytic reduction of uranium oxides to uranium metal in a fused salt electrolyte. Uranlum oxide such as UO/sub 2/ is mixed with somewhat less than the stoichiometric amount of carbon needed for the reduction, and the mixture is baked and crushed to make a nonspherical material. The latter is then mixed with a carbon binder sufficient to satisfy stoichiometry, pressed into a shape such as a cylinder, and baked. (AEC)

Complete reduction of high-density UO2 to metallic U in molten Li2O-LiCl

NASA Astrophysics Data System (ADS)

Choi, Eun-Young; Lee, Jeong

2017-10-01

The large size and high density of spent fuel pellets make it difficult to use the pellets directly in electrolytic reduction (also called as oxide reduction, OR) for pyroprocessing owing to the slow diffusion of molten Li2O-LiCl salt electrolyte into the pellets. In this study, we investigated complete OR of high-density UO2 to metallic U without any remaining UO2. Only partial reductions near the surface of high-density UO2 pellets were observed under operation conditions employing fast electrolysis rate that allowed previously complete reduction of low-density UO2 pellets. Complete reduction of high-density UO2 pellets was observed at fast electrolysis rate when the pellet size was reduced. The complete reduction of high-density UO2 pellets without size reduction was achieved at slow electrolysis rate, which allowed sufficient chemical reduction of UO2 with the lithium metal generated by the cathode reaction.

The Electrolyte Factor in O2 Reduction Electrocatalysis

DTIC Science & Technology

1993-04-23

molecule thick and does not seem to interfere with 02 and water/proton transport at this interface. This layer resembles a self-ordered Langmuir - Blodgett ... liquid electrolyte from within the polymer is in contact with the catalyst and completes the ionic circuit between the ionic conducting polymer and the...the free energy of adsorption of H2 0 and ionic components because of the lower effective dielectric constant in the electrolyte phase immediately

Guided Lithium Metal Deposition and Improved Lithium Coulombic Efficiency through Synergistic Effects of LiAsF 6 and Cyclic Carbonate Additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Xiaodi; Zhang, Yaohui; Engelhard, Mark H.

Spatial and morphology control over lithium (Li) metal nucleation/growth, as well as improving Li Coulombic efficiency (CE) are of the most challenging issues for rechargeable Li metal batteries. Here, we report that LiAsF6 and vinylene carbonate (VC) can work synergistically to address these challenges. It is revealed that AsF6- can be reduced to Li3As and LiF, which can act as seeds for Li growth and form a robust solid electrolyte interphase (SEI) layer, respectively. The addition of VC is critical because it not only enables uniform AsF6- reduction by passivating the defect sites on Cu substrate, but also improves themore » SEI layer flexibility during the reductive polymerization process. As a result, highly compact, uniform and dendrite-free Li film with vertically aligned columns structure can be obtained with greatly increased Li CE, and the Li metal batteries using the electrolyte with both LiAsF6 and VC additives can have much improved cycle life.« less

Solvent decompositions and physical properties of decomposition compounds in Li-ion battery electrolytes studied by DFT calculations and molecular dynamics simulations.

PubMed

Tasaki, Ken

2005-02-24

The density functional theory (DFT) calculations have been performed for the reduction decompositions of solvents widely used in Li-ion secondary battery electrolytes, ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonates (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), including a typical electrolyte additive, vinylene carbonate (VC), at the level of B3LYP/6-311+G(2d,p), both in the gas phase and solution using the polarizable conductor calculation model. In the gas phase, the first electron reduction for the cyclic carbonates and for the linear carbonates is found to be exothermic and endothermic, respectively, while the second electron reduction is endothermic for all the compounds examined. On the contrary, in solution both first and second electron reductions are exothermic for all the compounds. Among the solvents and the additive examined, the likelihood of undergoing the first electron reduction in solution was found in the order of EC > PC > VC > DMC > EMC > DEC with EC being the most likely reduced. VC, on the other hand, is most likely to undergo the second electron reduction among the compounds, in the order of VC > EC > PC. Based on the results, the experimentally demonstrated effectiveness of VC as an excellent electrolyte additive was discussed. The bulk thermodynamic properties of two dilithium alkylene glycol dicarbonates, dilithium ethylene glycol dicarbonate (Li-EDC) and dilithium 1,2-propylene glycol dicarbonate (Li-PDC), as the major component of solid-electrolyte interface (SEI) films were also examined through molecular dynamics (MD) simulations in order to understand the stability of the SEI film. It was found that film produced from a decomposition of EC, modeled by Li-EDC, has a higher density, more cohesive energy, and less solubility to the solvent than the film produced from decomposition of PC, Li-PDC. Further, MD simulations of the interface between the decomposition compound and graphite suggested that Li-EDC has more favorable interactions with the graphite surface than Li-PDC. The difference in the SEI film stability and the behavior of Li-ion battery cycling among the solvents were discussed in terms of the molecular structures.

The lithium storage performance of electrolytic-carbon from CO2

NASA Astrophysics Data System (ADS)

Tang, Juanjuan; Deng, Bowen; Xu, Fei; Xiao, Wei; Wang, Dihua

2017-02-01

Sustainable and affordable energy resources are urgently demanded to mitigate environmental issues. Herein, carbon materials, prepared by electrochemical reduction of greenhouse gas, CO2, in Li-Na-K carbonate molten salts (electrolytic-carbon), are tested as negative electrode materials for Li-ion batteries. Owing to the small particle size and suitable surface area, the electrolytic-carbon exhibits a high reversible capacity of 798 mAh g-1 (more than two times of graphites' theoretical capacity) at 50 mA g-1 and 266 mAh g-1 with a stable cyclability over 500 cycles at a current density up to 500 mA g-1, as well as remarkable rate performance. Furthermore, a comprehensively study was conducted to investigate the effects of electrolysis temperature and cell voltage on the electrochemical performance of the electrolytic-carbon. These results demonstrate a promising strategy to develop renewable high-performance carbon negative electrode materials for Li-ion batteries by molten salt capture and electrochemical reduction of CO2.

Exploration of the Detailed Conditions for Reductive Stability of Mg(TFSI) 2 in Diglyme: Implications for Multivalent Electrolytes

DOE PAGES

Baskin, Artem; Prendergast, David

2016-02-05

In this paper, we reveal the general mechanisms of partial reduction of multivalent complex cations in conditions specific for the bulk solvent and in the vicinity of the electrified metal electrode surface and disclose the factors affecting the reductive stability of electrolytes for multivalent electrochemistry. Using a combination of ab initio techniques, we clarify the relation between the reductive stability of contact-ion pairs comprising a multivalent cation and a complex anion, their solvation structures, solvent dynamics, and the electrode overpotential. We found that for ion pairs with multiple configurations of the complex anion and the Mg cation whose available orbitalsmore » are partially delocalized over the molecular complex and have antibonding character, the primary factor of the reductive stability is the shape factor of the solvation sphere of the metal cation center and the degree of the convexity of a polyhedron formed by the metal cation and its coordinating atoms. We focused specifically on the details of Mg (II) bis(trifluoromethanesulfonyl)imide in diethylene glycol dimethyl ether (Mg(TFSI) 2)/diglyme) and its singly charged ion pair, MgTFSI +. In particular, we found that both stable (MgTFSI) + and (MgTFSI) 0 ion pairs have the same TFSI configuration but drastically different solvation structures in the bulk solution. This implies that the MgTFSI/dyglyme reductive stability is ultimately determined by the relative time scale of the solvent dynamics and electron transfer at the Mg–anode interface. In the vicinity of the anode surface, steric factors and hindered solvent dynamics may increase the reductive stability of (MgTFSI) + ion pairs at lower overpotential by reducing the metal cation coordination, in stark contrast to the reduction at high overpotential accompanied by TFSI decomposition. By examining other solute/solvent combinations, we conclude that the electrolytes with highly coordinated Mg cation centers are more prone to reductive instability due to the chemical decomposition of the anion or solvent molecules. Finally, the obtained findings disclose critical factors for stable electrolyte design and show the role of interfacial phenomena in reduction of multivalent ions.« less

Methods and electrolytes for electrodeposition of smooth films

DOEpatents

Zhang, Jiguang; Xu, Wu; Graff, Gordon L; Chen, Xilin; Ding, Fei; Shao, Yuyan

2015-03-17

Electrodeposition involving an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and/or film surface. For electrodeposition of a first conductive material (C1) on a substrate from one or more reactants in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second conductive material (C2), wherein cations of C2 have an effective electrochemical reduction potential in the solution lower than that of the reactants.

Apparatus and method for electrochemical modification of liquids

DOEpatents

James, Patrick I

2015-04-21

An apparatus for electrochemical modification of liquid streams employing an electrolytic cell which includes an anode compartment defined by an anode structure where oxidation is effected, containing a liquid electrolyte anolyte, and a cathode compartment defined by a cathode structure where reduction is effected containing a liquid electrolyte catholyte. In addition, the electrolytic cell includes at least one additional compartment arranged at least partially between the anode compartment and the cathode compartment and separated from the anode compartment and the cathode compartment by a separator structure arranged to supports ionic conduction of current between the anode structure and the cathode structure.

Highly uniform and monodisperse carbon nanospheres enriched with cobalt-nitrogen active sites as a potential oxygen reduction electrocatalyst

NASA Astrophysics Data System (ADS)

Wan, Xing; Wang, Hongjuan; Yu, Hao; Peng, Feng

2017-04-01

Uniform cobalt and nitrogen co-doped carbon nanospheres (CoN-CNS) with high specific surface area (865 m2 g-1) have been prepared by a simple but efficient method. The prepared CoN-CNS catalyst exhibits outstanding catalytic performance for the oxygen reduction reaction (ORR) in both alkaline and acidic electrolytes. In alkaline electrolyte, the prepared CoN-CNS has more positive half-wave potential and larger kinetic current density than commercial Pt/C. In acidic electrolyte, CoN-CNS also shows good ORR activity with high electron transfer number, its onset and half-wave potentials are all close to those of commercial carbon supported platinum catalyst (Pt/C). CoN-CNS catalyst shows more superior stability and higher methanol-tolerance than commercial Pt/C both in alkaline and in acidic electrolytes. The potassium thiocyanate-poisoning test further confirms that the cobalt-nitrogen active sites exist in CoN-CNS, which are dominating to endow high ORR catalytic activity in acidic electrolyte. This study develops a new method to prepare non-precious metal catalyst with excellent ORR performances for direct methanol fuel cells.

Continuous process to produce lithium-polymer batteries

DOEpatents

Chern, Terry Song-Hsing; Keller, David Gerard; MacFadden, Kenneth Orville

1998-01-01

Solid polymer electrolytes are extruded with active electrode material in a continuous, one-step process to form composite electrolyte-electrodes ready for assembly into battery cells. The composite electrolyte-electrode sheets are extruded onto current collectors to form electrodes. The composite electrodes, as extruded, are electronically and ionically conductive. The composite electrodes can be overcoated with a solid polymer electrolyte, which acts as a separator upon battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte separator has low resistance.

Anode shroud for off-gas capture and removal from electrolytic oxide reduction system

DOEpatents

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

2014-07-08

An electrolytic oxide reduction system according to a non-limiting embodiment of the present invention may include a plurality of anode assemblies and an anode shroud for each of the anode assemblies. The anode shroud may be used to dilute, cool, and/or remove off-gas from the electrolytic oxide reduction system. The anode shroud may include a body portion having a tapered upper section that includes an apex. The body portion may have an inner wall that defines an off-gas collection cavity. A chimney structure may extend from the apex of the upper section and be connected to the off-gas collection cavity of the body portion. The chimney structure may include an inner tube within an outer tube. Accordingly, a sweep gas/cooling gas may be supplied down the annular space between the inner and outer tubes, while the off-gas may be removed through an exit path defined by the inner tube.

Fluid-electrolyte shifts and maximal oxygen uptake in man at simulated altitude /2,287 m/

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Bernauer, E. M.; Adams, W. C.; Juhos, L.

1978-01-01

Experiments were conducted on six trained distance runners (21-23 yr) subjected to an eight-day dietary control at sea level, followed by an eight-day stay in an altitude chamber (2287-m altitude) and a four-day recovery at sea level. Fluid and electrolyte shifts during exercise at altitude were evaluated to gain insight into the mechanism of reduction in working capacity. The results are discussed in terms of resting fluid volumes and blood constituents, maximal exercise variables, and maximal exercise fluid-electrolyte shifts. Since there are no significant changes in fluid balance or resting plasma volume (PV) at altitude, it is concluded that neither these nor the excessive PV shifts with exercise contribute to the reduction in maximal oxygen uptake at altitude. During altitude exposure the percent loss in PV is found to follow the percent reduction in maximal oxygen uptake; however, on the first day of recovery the percent change in PV remains depressed while maximal oxygen uptake returns to control levels.

Effects of common groundwater ions on chromate removal by magnetite: Importance of chromate adsorption

DOE PAGES

Meena, Amanda H.; Arai, Yuji

2016-04-29

Reductive precipitation of hexavalent chromium (Cr(VI)) with magnetite is a well-known Cr(VI) remediation method to improve water quality. The rapid (< a few hr) reduction of soluble Cr(VI) to insoluble Cr(III) species by Fe(II) in magnetite has been the primary focus of the Cr(VI) removal process in the past. However, the contribution of simultaneous Cr(VI) adsorption processes in aged magnetite has been largely ignored, leaving uncertainties in evaluating the application of in situ Cr remediation technologies for aqueous systems. In this study, effects of common groundwater ions (i.e., nitrate and sulfate) on Cr(VI) sorption to magnetite were investigated using batchmore » geochemical experiments in conjunction with X-ray absorption spectroscopy. As a result, in both nitrate and sulfate electrolytes, batch sorption experiments showed that Cr(VI) sorption decreases with increasing pH from 4 to 8. In this pH range, Cr(VI) sorption decreased with increasing ionic strength of sulfate from 0.01 to 0.1 M whereas nitrate concentrations did not alter the Cr(VI) sorption behavior. This indicates the background electrolyte specific Cr(VI) sorption process in magnetite. Under the same ionic strength, Cr(VI) removal in sulfate containing solutions was greater than that in nitrate solutions. This is because the oxidation of Fe(II) by nitrate is more thermodynamically favorable than by sulfate, leaving less reduction capacity of magnetite to reduce Cr(VI) in the nitrate media. X-ray absorption spectroscopy analysis supports the macroscopic evidence that more than 75 % of total Cr on the magnetite surfaces was adsorbed Cr(VI) species after 48 h. In conclusion, this experimental geochemical study showed that the adsorption process of Cr(VI) anions was as important as the reductive precipitation of Cr(III) in describing the removal of Cr(VI) by magnetite, and these interfacial adsorption processes could be impacted by common groundwater ions like sulfate and nitrate. The results of this study highlight new information about the large quantity of adsorbed Cr(VI) surface complexes at the magnetite-water interface. It has implications for predicting the long-term stability of Cr at the magnetite-water interface.« less

Optimization of electrochemical dechlorination of trichloroethylene in reducing electrolytes

PubMed Central

Mao, Xuhui; Ciblak, Ali; Baek, Kitae; Amiri, Mohammad; Loch-Caruso, Rita; Alshawabkeh, Akram N.

2012-01-01

Electrochemical dechlorination of trichloroethylene (TCE) in aqueous solution is investigated in a closed, liquid-recirculation system. The anodic reaction of cast iron generates ferrous species, creating a chemically reducing electrolyte (negative ORP value). The reduction of TCE on the cathode surface is enhanced under this reducing electrolyte because of the absence of electron competition. In the presence of the iron anode, the performances of different cathodes are compared in a recirculated electrolysis system. The copper foam shows superior capability for dechlorination of aqueous TCE. Electrolysis by cast iron anode and copper foam cathode is further optimized though a multivariable experimental design and analysis. The conductivity of the electrolyte is identified as an important factor for both final elimination efficiency (FEE) of TCE and specific energy consumption. The copper foam electrode exhibits high TCE elimination efficiency in a wide range of initial TCE concentration. Under coulostatic conditions, the optimal conditions to achieve the highest FEE are 9.525 mm thick copper foam electrode, 40 mA current and 0.042 mol L−1 Na2SO4. This novel electrolysis system is proposed to remediate groundwater contaminated by chlorinated organic solvents, or as an improved iron electrocoagulation process capable of treating the wastewater co-contaminated with chlorinated compounds. PMID:22264798

Ceramic electrolyte coating and methods

DOEpatents

Seabaugh, Matthew M [Columbus, OH; Swartz, Scott L [Columbus, OH; Dawson, William J [Dublin, OH; McCormick, Buddy E [Dublin, OH

2007-08-28

Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

Electrolytic process for preparing uranium metal

DOEpatents

Haas, Paul A.

1990-01-01

An electrolytic process for making uranium from uranium oxide using Cl.sub.2 anode product from an electrolytic cell to react with UO.sub.2 to form uranium chlorides. The chlorides are used in low concentrations in a melt comprising fluorides and chlorides of potassium, sodium and barium in the electrolytic cell. The electrolysis produces Cl.sub.2 at the anode that reacts with UO.sub.2 in the feed reactor to form soluble UCl.sub.4, available for a continuous process in the electrolytic cell, rather than having insoluble UO.sub.2 fouling the cell.

High Rate Oxygen Reduction in Non-aqueous Electrolytes with the Addition of Perfluorinated Additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Y.; Yang, X.; Zheng, D.

2011-08-04

The discharge rate capability of Li-air batteries is substantially increased by using perfluorinated compounds as oxygen carriers. The solubility of oxygen in a non-aqueous electrolyte can be significantly increased by the introduction of such compounds, which leads to the increase in the diffusion-limited current of oxygen reduction on the gas diffusion electrode in a Li-air battery. The perfluorinated compound is found to be stable within the electrochemical window of the electrolyte. A powder microelectrode and a rotating disk electrode were used to study the gas diffusion-limited current together with a rotating disk electrode. A 5 mA cm{sup -2} discharge ratemore » is demonstrated in a lab Li-O{sub 2} cell.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shkrob, Ilya A.; Pupek, Krzysztof Z.; Gilbert, James A.

Lithium hexafluorophosphate (LiPF 6) is ubiquitous in commercial lithium-ion batteries, but it is hydrolytically unstable and corrosive on electrode surfaces. Using a more stable salt would confer multiple benefits for high-voltage operation, but many such electrolyte systems facilitate anodic dissolution and pitting corrosion of aluminum current collectors that negate their advantages. Lithium 2-trifluoromethyl-4,5-dicyanoimidazolide (LiTDI) is a new salt that was designed specifically for high-voltage cells. In this study we demonstrate that in carbonate electrolytes, LiTDI prevents anodic dissolution of Al current collectors, which places it into a select group of corrosion inhibitors. However, we also demonstrate that LiTDI becomes reducedmore » on lithiated graphite, undergoing sequential defluorination and yielding a thick and resistive solid-electrolyte interphase (SEI), which increases impedance and lowers electrode capacity. The mechanistic causes for this behavior are examined using computational chemistry methods in the light of recent spectroscopic studies. Here, we demonstrate that LiTDI reduction can be prevented by certain electrolyte additives, which include fluoroethylene carbonate, vinylene carbonate and lithium bis(oxalato)borate. This beneficial action is due to preferential reduction of these additives over LiTDI at a higher potential vs. Li/Li +, so the resulting SEI can prevent the direct reduction of LiTDI at lower potentials on the graphite electrode.« less

Solid oxide fuel cell operable over wide temperature range

DOEpatents

Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

2001-01-01

Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

Interfacial material for solid oxide fuel cell

DOEpatents

Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

1999-01-01

Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

The influence of the carbonate species on LiNi0.8Co0.15Al0.05O2 surfaces for all-solid-state lithium ion battery performance

NASA Astrophysics Data System (ADS)

Visbal, Heidy; Fujiki, Satoshi; Aihara, Yuichi; Watanabe, Taku; Park, Youngsin; Doo, Seokgwang

2014-12-01

The influence of selected carbonate species on LiNi0.8Co0.15Al0.05O2 (NCA) surface for all-solid-state lithium-ion battery (ASSB) with a sulfide based solid electrolyte was studied for its electrochemical properties, structural stabilities, and surface characteristics. The rated discharge performance improved with the reduction of the carbonate concentration on the NCA surface due to the decrease of the interface resistance. The species and coordination of the adsorbed carbonates on the NCA surface were analyzed by diffuse reflectance Fourier transformed infrared (DRIFT) spectroscopy. The coordination of the adsorbed carbonate anion was determined based on the degree of splitting of the ν3(CO) stretching vibrations. It is found that the surface carbonate species exists in an unidentate coordination on the surface. They react with the sulfide electrolyte to form an irreversible passivation layer. This layer obstructs the charge transfer process at the cathode/electrolyte interface, and results in the rise of the interface resistance and drop of the rated discharge capability.

Electrochemical aspects of copper atmospheric corrosion in the presence of sodium chloride

DOE PAGES

Schindelholz, Eric John; Cong, Hongbo; Jove-Colon, Carlos F.; ...

2018-04-26

Here, this study describes the evolving state of electrolyte and corrosion processes associated with sodium chloride on copper at the initial stage of corrosion and the critical implications of this behavior on controlling kinetics and damage distributions. Sodium chloride droplets were placed on copper in humid conditions and the resulting electrolyte properties, corrosion products and damage were characterized over time using time-lapse imaging, micro Raman spectroscopy, TOF-SIMS and optical profilometry. Within minutes of NaCl droplet placement, NaOH-rich films resultant from oxygen reduction advanced stepwise from the droplets, leaving behind concentric trenching attack patterns suggestive of moving anode-cathode pairs at themore » alkaline film front. Corrosion attack under these spreading alkaline films was up to 10x greater than under the original NaCl drops. Furthermore, solid Cu 2Cl(OH) 3 shells formed over the surface of the NaCl drops within hours of exposure. Thermodynamic modeling along with immersed electrochemical experiments in simulated droplet and films electrolytes were used to rationalize this behavior and build a description of the rapidly evolving corroding system.« less

Electrochemical aspects of copper atmospheric corrosion in the presence of sodium chloride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schindelholz, Eric John; Cong, Hongbo; Jove-Colon, Carlos F.

Here, this study describes the evolving state of electrolyte and corrosion processes associated with sodium chloride on copper at the initial stage of corrosion and the critical implications of this behavior on controlling kinetics and damage distributions. Sodium chloride droplets were placed on copper in humid conditions and the resulting electrolyte properties, corrosion products and damage were characterized over time using time-lapse imaging, micro Raman spectroscopy, TOF-SIMS and optical profilometry. Within minutes of NaCl droplet placement, NaOH-rich films resultant from oxygen reduction advanced stepwise from the droplets, leaving behind concentric trenching attack patterns suggestive of moving anode-cathode pairs at themore » alkaline film front. Corrosion attack under these spreading alkaline films was up to 10x greater than under the original NaCl drops. Furthermore, solid Cu 2Cl(OH) 3 shells formed over the surface of the NaCl drops within hours of exposure. Thermodynamic modeling along with immersed electrochemical experiments in simulated droplet and films electrolytes were used to rationalize this behavior and build a description of the rapidly evolving corroding system.« less

Fluorescence Quenching of Humic Acid by Coated Metallic Silver Particles.

PubMed

Zhu, Guocheng; Yin, Jun

2017-07-01

Natural organic matter is an important component of the aquatic environments, which has attracted wide attention to its influence of interaction with other pollutants. The present work aimed to investigate its fluorescence quenching (FQ) by coated metallic silver particles (AgNPs). In this work, using fluorescence spectroscopy in conjunction with UV-Vis spectroscopy and dynamic light scattering, the effect of coated AgNPs on fluorescence quenching intensity (FQI) of humic acid (HA) was assessed. In addition, the influence of electrolytes (NaCl, NaNO 3 and CaNO 3 ) in the FQI was observed. Results showed that with AgNPs dosage increased (>1.17X10 -3  mM), fluorescence quantum yield of HA gradually decreased, which implies that the FQ occurred. Furher observation showed that the FQ process followed both first-order and second-order Stern-Volmer functions. The FQ process was affected by the electrolytes: NaCl had an effect on reduction of FQI, possibly resulting from dissolution of AgNPs; Both of NaNO 3 and Ca(NO 3 ) 2 had an effect on the FQ of HA but Ca(NO 3 ) 2 presented greater degree. As a result, the FQ degree of HA by alone electrolyte was listed in descent order as Ca(NO 3 ) 2  > NaNO 3  > NaCl, which also implies the subsequent experimental results, indicating the FQ degree of HA by mutual electrolytes as Ca(NO 3 ) 2  + NaNO 3  > Ca(NO 3 ) 2  + NaCl > NaNO 3  + NaCl.

Continuous process to produce lithium-polymer batteries

DOEpatents

Chern, T.S.H.; Keller, D.G.; MacFadden, K.O.

1998-05-12

Solid polymer electrolytes are extruded with active electrode material in a continuous, one-step process to form composite electrolyte-electrodes ready for assembly into battery cells. The composite electrolyte electrode sheets are extruded onto current collectors to form electrodes. The composite electrodes, as extruded, are electronically and ionically conductive. The composite electrodes can be over coated with a solid polymer electrolyte, which acts as a separator upon battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte separator has low resistance. 1 fig.

One step electrodeposition of Cu2ZnSnS4 thin films in a novel bath with sulfurization free annealing

NASA Astrophysics Data System (ADS)

Tang, Aiyue; Li, Zhilin; Wang, Feng; Dou, Meiling; Pan, Youya; Guan, Jingyu

2017-04-01

Cu2ZnSnS4 (CZTS) is a quaternary kesterite compound with suitable band gap for thin film solar cells. In most electrodeposition-anneal routes, sulfurization is inevitable because the as-deposited film is lack of S. In this work, a novel green electrolyte was designed for synthesizing CZTS thin films with high S content. In the one-step electrodeposition, K4P2O7 and C7H6O6S were added to form complex with metallic ions in the electrolyte, which could attribute to co-deposition. The as-deposited film obtained high S content satisfying stoichiometry. After a sulfurization free annealing, the continuous and uniform CZTS thin film was obtained, which had pure kesterite structure and a suitable band gap of 1.53 eV. Electrodeposition mechanism investigation revealed that the K4P2O7 prevented the excessive deposition of Cu2+ and Sn2+. The C7H6O6S promoted the reduction of Zn2+. So the additives narrowed the co-deposition potentials of the metallic elements through a synergetic effect. They also promoted the reduction of S2O32- to ensure the co-deposition of the four elements and the stoichiometry. The sulfurization free annealing process can promote the commercialization of CZTS films and the successful design principle of environmental friendly electrolytes could be applied in other electrodeposition systems.

Electrolytic oxide reduction system

DOEpatents

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

2015-04-28

An electrolytic oxide reduction system according to a non-limiting embodiment of the present invention may include a plurality of anode assemblies, a plurality of cathode assemblies, and a lift system configured to engage the anode and cathode assemblies. The cathode assemblies may be alternately arranged with the anode assemblies such that each cathode assembly is flanked by two anode assemblies. The lift system may be configured to selectively engage the anode and cathode assemblies so as to allow the simultaneous lifting of any combination of the anode and cathode assemblies (whether adjacent or non-adjacent).

Computational Exploration of the Li-Electrode|Electrolyte Interface in the Presence of a Nanometer Thick Solid-Electrolyte Interphase Layer [Computational exploration of the Li-electrode|electrolyte interface complicated by a nanometer thin solid-electrolyte interphase (SEI) layer

DOE PAGES

Li, Yunsong; Leung, Kevin; Qi, Yue

2016-09-30

A nanometer thick passivation layer will spontaneously form on Li-metal in battery applications due to electrolyte reduction reactions. This passivation layer in rechargeable batteries must have “selective” transport properties: blocking electrons from attacking the electrolytes, while allowing Li + ion to pass through so the electrochemical reactions can continue. The classical description of the electrochemical reaction, Li + + e → Li 0, occurring at the Li-metal|electrolyte interface is now complicated by the passivation layer and will reply on the coupling of electronic and ionic degrees of freedom in the layer. We consider the passivation layer, called “solid electrolyte interphasemore » (SEI)”, as “the most important but the least understood in rechargeable Li-ion batteries,” partly due to the lack of understanding of its structure–property relationship. In predictive modeling, starting from the ab initio level, we find that it is an important tool to understand the nanoscale processes and materials properties governing the interfacial charge transfer reaction at the Li-metal|SEI|electrolyte interface. Here, we demonstrate pristine Li-metal surfaces indeed dissolve in organic carbonate electrolytes without the SEI layer. Based on joint modeling and experimental results, we point out that the well-known two-layer structure of SEI also exhibits two different Li + ion transport mechanisms. The SEI has a porous (organic) outer layer permeable to both Li + and anions (dissolved in electrolyte), and a dense (inorganic) inner layer facilitate only Li + transport. This two-layer/two-mechanism diffusion model suggests only the dense inorganic layer is effective at protecting Li-metal in electrolytes. This model suggests a strategy to deconvolute the structure–property relationships of the SEI by analyzing an idealized SEI composed of major components, such as Li 2CO 3, LiF, Li 2O, and their mixtures. After sorting out the Li+ ion diffusion carriers and their diffusion pathways, we design methods to accelerate the Li + ion conductivity by doping and by using heterogonous structure designs. We will predict the electron tunneling barriers and connect them with measurable first cycle irreversible capacity loss. We note that the SEI not only affects Li + and e – transport, but it can also impose a potential drop near the Li-metal|SEI interface. Our challenge is to fully describe the electrochemical reactions at the Li -metal|SEI|electrolyte interface. This will be the subject of ongoing efforts.« less

Computational Exploration of the Li-Electrode|Electrolyte Interface in the Presence of a Nanometer Thick Solid-Electrolyte Interphase Layer [Computational exploration of the Li-electrode|electrolyte interface complicated by a nanometer thin solid-electrolyte interphase (SEI) layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yunsong; Leung, Kevin; Qi, Yue

A nanometer thick passivation layer will spontaneously form on Li-metal in battery applications due to electrolyte reduction reactions. This passivation layer in rechargeable batteries must have “selective” transport properties: blocking electrons from attacking the electrolytes, while allowing Li + ion to pass through so the electrochemical reactions can continue. The classical description of the electrochemical reaction, Li + + e → Li 0, occurring at the Li-metal|electrolyte interface is now complicated by the passivation layer and will reply on the coupling of electronic and ionic degrees of freedom in the layer. We consider the passivation layer, called “solid electrolyte interphasemore » (SEI)”, as “the most important but the least understood in rechargeable Li-ion batteries,” partly due to the lack of understanding of its structure–property relationship. In predictive modeling, starting from the ab initio level, we find that it is an important tool to understand the nanoscale processes and materials properties governing the interfacial charge transfer reaction at the Li-metal|SEI|electrolyte interface. Here, we demonstrate pristine Li-metal surfaces indeed dissolve in organic carbonate electrolytes without the SEI layer. Based on joint modeling and experimental results, we point out that the well-known two-layer structure of SEI also exhibits two different Li + ion transport mechanisms. The SEI has a porous (organic) outer layer permeable to both Li + and anions (dissolved in electrolyte), and a dense (inorganic) inner layer facilitate only Li + transport. This two-layer/two-mechanism diffusion model suggests only the dense inorganic layer is effective at protecting Li-metal in electrolytes. This model suggests a strategy to deconvolute the structure–property relationships of the SEI by analyzing an idealized SEI composed of major components, such as Li 2CO 3, LiF, Li 2O, and their mixtures. After sorting out the Li+ ion diffusion carriers and their diffusion pathways, we design methods to accelerate the Li + ion conductivity by doping and by using heterogonous structure designs. We will predict the electron tunneling barriers and connect them with measurable first cycle irreversible capacity loss. We note that the SEI not only affects Li + and e – transport, but it can also impose a potential drop near the Li-metal|SEI interface. Our challenge is to fully describe the electrochemical reactions at the Li -metal|SEI|electrolyte interface. This will be the subject of ongoing efforts.« less

Methods and energy storage devices utilizing electrolytes having surface-smoothing additives

DOEpatents

Xu, Wu; Zhang, Jiguang; Graff, Gordon L; Chen, Xilin; Ding, Fei

2015-11-12

Electrodeposition and energy storage devices utilizing an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and anode surface. For electrodeposition of a first metal (M1) on a substrate or anode from one or more cations of M1 in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second metal (M2), wherein cations of M2 have an effective electrochemical reduction potential in the solution lower than that of the cations of M1.

Electrolytic exfoliation of graphite in water with multifunctional electrolytes: en route towards high quality, oxide-free graphene flakes.

PubMed

Munuera, J M; Paredes, J I; Villar-Rodil, S; Ayán-Varela, M; Martínez-Alonso, A; Tascón, J M D

2016-02-07

Electrolytic--usually referred to as electrochemical--exfoliation of graphite in water under anodic potential holds enormous promise as a simple, green and high-yield method for the mass production of graphene, but currently suffers from several drawbacks that hinder its widespread adoption, one of the most critical being the oxidation and subsequent structural degradation of the carbon lattice that is usually associated with such a production process. To overcome this and other limitations, we introduce and implement the concept of multifunctional electrolytes. The latter are amphiphilic anions (mostly polyaromatic hydrocarbons appended with sulfonate groups) that play different relevant roles as (1) an intercalating electrolyte to trigger exfoliation of graphite into graphene flakes, (2) a dispersant to afford stable aqueous colloidal suspensions of the flakes suitable for further use, (3) a sacrificial agent to prevent graphene oxidation during exfoliation and (4) a linker to promote nanoparticle anchoring on the graphene flakes, yielding functional hybrids. The implementation of this strategy with some selected amphiphiles even furnishes anodically exfoliated graphenes of a quality similar to that of flakes produced by direct, ultrasound- or shear-induced exfoliation of graphite in the liquid phase (i.e., almost oxide- and defect-free). These high quality materials were used for the preparation of catalytically efficient graphene-Pt nanoparticle hybrids, as demonstrated by model reactions (reduction of nitroarenes). The multifunctional performance of these electrolytes is also discussed and rationalized, and a mechanistic picture of their oxidation-preventing ability is proposed. Overall, the present results open the prospect of anodic exfoliation as a competitive method for the production of very high quality graphene flakes.

Highly conducting leakage-free electrolyte for SrCoOx-based non-volatile memory device

NASA Astrophysics Data System (ADS)

Katase, Takayoshi; Suzuki, Yuki; Ohta, Hiromichi

2017-10-01

The electrochemical switching of SrCoOx-based non-volatile memory with a thin-film-transistor structure was examined by using liquid-leakage-free electrolytes with different conductivities (σ) as the gate insulator. We first examined leakage-free water, which is incorporated in the amorphous (a-) 12CaO.7Al2O3 film with a nanoporous structure (Calcium Aluminate with Nanopore), but the electrochemical oxidation/reduction of the SrCoOx layer required the application of a high gate voltage (Vg) up to 20 V for a very long current-flowing-time (t) ˜40 min, primarily due to the low σ [2.0 × 10-8 S cm-1 at room temperature (RT)] of leakage-free water. We then controlled the σ of the leakage-free electrolyte, infiltrated in the a-NaxTaO3 film with a nanopillar array structure, from 8.0 × 10-8 S cm-1 to 2.5 × 10-6 S cm-1 at RT by changing the x = 0.01-1.0. As the result, the t, required for the metallization of the SrCoOx layer under small Vg = -3 V, becomes two orders of magnitude shorter with increase of the σ of the a-NaxTaO3 leakage-free electrolyte. These results indicate that the ion migration in the leakage-free electrolyte is the rate-determining step for the electrochemical switching, compared to the other electrochemical process, and the high σ of the leakage-free electrolyte is the key factor for the development of the non-volatile SrCoOx-based electro-magnetic phase switching device.

Deliberate modification of the solid electrolyte interphase (SEI) during lithiation of magnetite, Fe 3O 4: impact on electrochemistry

DOE PAGES

Bock, David C.; Marschilok, Amy C.; Takeuchi, Kenneth J.; ...

2017-11-20

Here, magnetite is a conversion anode material displaying multi-electron transfer during lithiation and delithiation. The solid electrolyte interphase (SEI) on magnetite, Fe 3O 4, electrodes for lithium ion batteries was deliberately modified through the use of fluoroethylene carbonate (FEC) electrolyte additive, improving both capacity retention and rate capability. Analysis showed reduction of FEC at higher voltage compared to non-fluorinated solvents with formation of a modified lithium flouride containing electrode surface.

Charge and discharge characteristics of lithium-ion graphite electrodes in solid-state cells

NASA Astrophysics Data System (ADS)

Lemont, S.; Billaud, D.

Lithium ions have been electrochemically intercalated into graphite in solid-state cells operating with solid polymer electrolytes based on poly(ethylene oxide) (PEO) complexed with lithium perchlorate (LiClO 4). The working composite electrode is composed of active-divided natural graphite associated with P(EO) 8-LiClO 4 acting as a binder and a Li + ionic conductor. Intercalation and de-intercalation of Li + were performed using galvanostatic or voltammetry techniques. The curves obtained in our solid-state cells were compared with those performed in liquid ethylene carbonate-LiClO 4 electrolyte. It is shown that in solid-state cells, side reactions occur both in the reduction and in the oxidation processes which leads to some uncertainty in the determination of the maximum reversible capacity of the graphite material.

Vibrational stark effects to identify ion pairing and determine reduction potentials in electrolyte-free environments

DOE PAGES

Mani, Tomoyasu; Grills, David C.; Miller, John R.

2015-01-02

A recently-developed instrument for time-resolved infrared detection following pulse radiolysis has been used to measure the ν(C≡N) IR band of the radical anion of a CN-substituted fluorene in tetrahydrofuran. Specific vibrational frequencies can exhibit distinct frequency shifts due to ion-pairing, which can be explained in the framework of the vibrational Stark effect. Measurements of the ratio of free ions and ion-pairs in different electrolyte concentrations allowed us to obtain an association constant and free energy change for ion-pairing. As a result, this new method has the potential to probe the geometry of ion-pairing and allows the reduction potentials of moleculesmore » to be determined in the absence of electrolyte in an environment of low dielectric constant.« less

One-step large-scale synthesis of micrometer-sized silver nanosheets by a template-free electrochemical method

NASA Astrophysics Data System (ADS)

Park, Sun Hwa; Son, Jin Gyeong; Lee, Tae Geol; Park, Hyun Min; Song, Jae Yong

2013-05-01

We have synthesized micrometer-sized Ag nanosheets via a facile, one-step, template-free electrochemical deposition in an ultra-dilute silver nitrate aqueous electrolyte. The nanosheet growth was revealed to occur in three stages: (1) formation of polygonal Ag nuclei on a substrate, (2) growth of {112}-faceted nanowire from the nuclei, and (3) anisotropic growth of (111)-planar nanosheets, approximately 20 to 50 nm in thickness and 10 μm in width, in the <112>-direction. The vertical growth of the facet nanowire was induced by the strong interface anisotropy between the deposit and electrolyte due to the ultra-dilute concentration of electrolyte and high reduction potential. The thickness of Ag nanosheets was controllable by the adjustment of the reduction/oxidation potential and frequency of the reverse-pulse potentiodynamic mode.

Evaluation of Selected Chemical Processes for Production of Low-cost Silicon, Phase 3. [using a fluidized bed reactor

NASA Technical Reports Server (NTRS)

Blocher, J. M., Jr.; Browning, M. F.

1979-01-01

The construction and operation of an experimental process system development unit (EPSDU) for the production of granular semiconductor grade silicon by the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles is presented. The construction of the process development unit (PDU) is reported. The PDU consists of four critical units of the EPSDU: the fluidized bed reactor, the reactor by product condenser, the zinc vaporizer, and the electrolytic cell. An experimental wetted wall condenser and its operation are described. Procedures are established for safe handling of SiCl4 leaks and spills from the EPSDU and PDU.

The Role of Sub- and Supercritical CO2 as "Processing Solvent" for the Recycling and Sample Preparation of Lithium Ion Battery Electrolytes.

PubMed

Nowak, Sascha; Winter, Martin

2017-03-06

Quantitative electrolyte extraction from lithium ion batteries (LIB) is of great interest for recycling processes. Following the generally valid EU legal guidelines for the recycling of batteries, 50 wt % of a LIB cell has to be recovered, which cannot be achieved without the electrolyte; hence, the electrolyte represents a target component for the recycling of LIBs. Additionally, fluoride or fluorinated compounds, as inevitably present in LIB electrolytes, can hamper or even damage recycling processes in industry and have to be removed from the solid LIB parts, as well. Finally, extraction is a necessary tool for LIB electrolyte aging analysis as well as for post-mortem investigations in general, because a qualitative overview can already be achieved after a few minutes of extraction for well-aged, apparently "dry" LIB cells, where the electrolyte is deeply penetrated or even gellified in the solid battery materials.

Artificially-built solid electrolyte interphase via surface-bonded vinylene carbonate derivative on graphite by molecular layer deposition

NASA Astrophysics Data System (ADS)

Chae, Seulki; Lee, Jeong Beom; Lee, Jae Gil; Lee, Tae-jin; Soon, Jiyong; Ryu, Ji Heon; Lee, Jin Seok; Oh, Seung M.

2017-12-01

Vinylene carbonate (VC) is attached in a ring-opened form on a graphite surface by molecular layer deposition (MLD) method, and its role as a solid electrolyte interphase (SEI) former is studied. When VC is added into the electrolyte solution of a graphite/LiNi0.5Mn1.5O4 (LNMO) full-cell, it is reductively decomposed to form an effective SEI on the graphite electrode. However, VC in the electrolyte solution has serious adverse effects due to its poor stability against electrochemical oxidation on the LNMO positive electrode. A excessive acid generation as a result of VC oxidation is observed, causing metal dissolution from the LNMO electrode. The dissolved metal ions are plated on the graphite electrode to destroy the SEI layer, eventually causing serious capacity fading and poor Coulombic efficiency. The VC derivative on the graphite surface also forms an effective SEI layer on the graphite negative electrode via reductive decomposition. The detrimental effects on the LNMO positive electrode, however, can be avoided because the bonded VC derivative on the graphite surface cannot move to the LNMO electrode. Consequently, the graphite/LNMO full-cell fabricated with the VC-attached graphite outperforms the cells without VC or with VC in the electrolyte, in terms of Coulombic efficiency and capacity retention.

New Insights into the Electroreduction of Ethylene Sulfite as Electrolyte Additive for Facilitating Solid Electrolyte Interphase of Lithium Ion Battery

PubMed Central

Sun, Youmin; Wang, Yixuan

2017-01-01

To help understand the solid electrolyte interphase (SEI) formation facilitated by electrolyte additives of lithium-ion batteries (LIB) the supermolecular clusters [(ES)Li+(PC)m](PC)n (m=1–2; n=0, 6, and 9) were used to investigate the electroreductive decompositions of the electrolyte additive, ethylene sulfite (ES), as well as the solvent, propylene carbonate (PC) with density functional theory. The results show that ES can be reduced prior to PC, resulting in a reduction precursor that will then undergo a ring opening decomposition to yield a radical anion. A new concerted pathway (path B) was located for the ring opening of the reduced ES, which has much lower energy barrier than the previously reported stepwise pathway (path A). The transition state for the ring opening of PC induced by the reduced ES (path C, indirect path) is closer to that of path A than path B in energy. The direct ring opening of the reduced PC (path D) has lower energy barrier than those of paths A, B and C, yet it is less favorable than the latter paths in terms of thermodynamics (vertical electron affinity or the reduction potential dissociation energy). The overall rate constant including the initial reduction and the subsequent ring opening for path B is the largest among the four paths, followed by paths A>C>D, which further signifies the importance of the concerted new path in facilitating the SEI. The hybrid models, the supermolecular cluster augmented by polarized continuum model, PCM-[(ES)Li+(PC)2](PC)n (n=0,6, and 9), were used to further estimate the reduction potential by taking into account both explicit and implicit solvent effects. The second solvation shell of Li+ in [(ES)Li+(PC)2](PC)n (n=6, and 9) partially compensates the overestimation of solvent effects arising from the PCM model for the naked (ES)Li+(PC)2, and the theoretical reduction potential with PCM-[(ES)Li+(PC)2](PC)6 (1.90–1.93V) agrees very well with the experimental one (1.8–2.0V). PMID:28220165

New insights into the electroreduction of ethylene sulfite as an electrolyte additive for facilitating solid electrolyte interphase formation in lithium ion batteries.

PubMed

Sun, Youmin; Wang, Yixuan

2017-03-01

To help understand the solid electrolyte interphase (SEI) formation facilitated by electrolyte additives of lithium-ion batteries (LIBs) the supermolecular clusters [(ES)Li + (PC) m ](PC) n (m = 1-2; n = 0, 6 and 9) were used to investigate the electroreductive decompositions of the electrolyte additive ethylene sulfite (ES) as well as the solvent propylene carbonate (PC) with density functional theory. The results show that ES can be reduced prior to PC, resulting in a reduction precursor that will then undergo a ring opening decomposition to yield a radical anion. A new concerted pathway (path B) was located for the ring opening of the reduced ES, which has a much lower energy barrier than the previously reported stepwise pathway (path A). The transition state for the ring opening of PC induced by the reduced ES (path C, indirect path) is closer to that of path A than path B in energy. The direct ring opening of the reduced PC (path D) has a lower energy barrier than paths A, B and C, yet it is less favorable than the latter paths in terms of thermodynamics (vertical electron affinity or reduction potential and dissociation energy). The overall rate constant including the initial reduction and the subsequent ring opening for path B is the largest among the four paths, followed by paths A > C > D, which further signifies the importance of the concerted new path in facilitating the SEI formation. The hybrid models, the supermolecular clusters augmented by a polarized continuum model, PCM-[(ES)Li + (PC) 2 ](PC) n (n = 0, 6 and 9), were used to further estimate the reduction potential by taking into account both explicit and implicit solvent effects. The second solvation shell of Li + in [(ES)Li + (PC) 2 ](PC) n (n = 6 and 9) partially compensates the overestimation of solvent effects arising from the PCM for the naked (ES)Li + (PC) 2 , and the theoretical reduction potential of PCM-[(ES)Li + (PC) 2 ](PC) 6 (1.90-1.93 V) agrees very well with the experimental one (1.8-2.0 V).

Chronopotentiometry of Refractory Metals, Actinides and Oxyanions in Molten Salts: A Review

DTIC Science & Technology

1992-09-01

disappaared. No new wave appeared which could be attributed to the nitrosonium , NO+, ion . The nitronium ion , N02+, could not be detected in the melt...electrodeposit- ion of coherent deposits of refractory metals from solutions in fused electrolytes. 2.1. Titanium. The electrochemical oxidation of Ti(II...the higher valent niobium ions were found to be electroactive. The reduction process was a reversible, one electron step with the product soluble in the

Towards Next Generation Lithium-Sulfur Batteries: Non-Conventional Carbon Compartments/Sulfur Electrodes and Multi-Scale Analysis

DOE PAGES

Dysart, Arthur D.; Burgos, Juan C.; Mistry, Aashutosh; ...

2016-02-09

In this work, a novel heterofunctional, bimodal-porous carbon morphology, termed the carbon compartment (CC), is utilized as a sulfur host as a lithium-sulfur battery cathode. A multi-scale model explores the physics and chemistry of the lithium-sulfur battery cathode. The CCs are synthesized by a rapid, low cost process to improve electrode-electrolyte interfacial contact and accommodate volumetric expansion associated with sulfide formation. The CCs demonstrate high sulfur loading (47 %-wt. S) and ca. 700 mAh g -1 reversible capacity with high coulombic efficiency due to their unique structures. Density functional theory and ab initio Molecular Dynamics characterize the interface between themore » C/S composite and electrolyte during the sulfur reduction mechanism. Stochastic realizations of 3D electrode microstructures are reconstructed based on representative SEM images to study the influence of solid sulfur loading and lithium sulfide precipitation on microstructural and electrochemical properties. A macroscale electrochemical performance model is developed to analyze the performance of lithium-sulfur batteries. The combined multi-scale simulation studies explain key fundamentals of sulfur reduction and its relation to the polysulfide shuttle mechanism: how the process is affected due to the presence of carbon substrate, thermodynamics of lithium sulfide formation and deposition on carbon, and microstructural effects on the overall cell performance.« less

Investigation of the electrocatalytic oxygen reduction and evolution reactions in lithium–oxygen batteries

DOE PAGES

Zheng, Dong; Zhang, Xuran; Qu, Deyu; ...

2015-04-21

Oxygen reduction and oxygen evolution reactions were examined on graphite electrodes with different crystal orientations. The kinetics for the redox couple O 2/O 2 •- are very fast, therefore no catalyst seems necessary to assist the charge transfer process. Apparently, the main source of the overpotential for the O 2 reduction reaction is from mass diffusion. Li 2O 2 becomes soluble in non-aqueous electrolytes in the presence of the tetraethylammonium tetrafluoroborate additive. The soluble B-O 2 2- ions can be oxidized electro-catalytically. The edge orientation of graphite demonstrates superior catalytic activity for the oxidation over basal orientation. The findings revealmore » an opportunity for recharging Li-air batteries efficiently and a new strategy of developing the catalyst for oxygen evolution reaction.« less

Multilayered composite proton exchange membrane and a process for manufacturing the same

DOEpatents

Santurri, Pasco R; Duvall, James H; Katona, Denise M; Mausar, Joseph T; Decker, Berryinne

2015-05-05

A multilayered membrane for use with fuel cells and related applications. The multilayered membrane includes a carrier film, at least one layer of an undoped conductive polymer electrolyte material applied onto the carrier film, and at least one layer of a conductive polymer electrolyte material applied onto the adjacent layer of polymer electrolyte material. Each layer of conductive polymer electrolyte material is doped with a plurality of nanoparticles. Each layer of undoped electrolyte material and doped electrolyte material may be applied in an alternating configuration, or alternatively, adjacent layers of doped conductive polymer electrolyte material is employed. The process for producing a multilayered composite membrane includes providing a carrier substrate and solution casting a layer of undoped conductive polymer electrolyte material and a layer of conductive polymer electrolyte material doped with nanoparticles in an alternating arrangement or in an arrangement where doped layers are adjacent to one another.

Rare Earth Electrochemical Property Measurements and Phase Diagram Development in a Complex Molten Salt Mixture for Molten Salt Recycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jinsuo; Guo, Shaoqiang

Pyroprocessing is a promising alternative for the reprocessing of used nuclear fuel (UNF) that uses electrochemical methods. Compared to the hydrometallurgical reprocessing method, pyroprocessing has many advantages such as reduced volume of radioactive waste, simple waste processing, ability to treat refractory material, and compatibility with fast reactor fuel recycle. The key steps of the process are the electro-refining of the spent metallic fuel in the LiCl-KCl eutectic salt, which can be integrated with an electrolytic reduction step for the reprocessing of spent oxide fuels.

Molecular Sieve Induced Solution Growth of Li2O2 in the Li-O2 Battery with Largely Enhanced Discharge Capacity.

PubMed

Yu, Wei; Wang, Huwei; Hu, Jing; Yang, Wei; Qin, Lei; Liu, Ruliang; Li, Baohua; Zhai, Dengyun; Kang, Feiyu

2018-03-07

The formation of the insulated film-like discharge products (Li 2 O 2 ) on the surface of the carbon cathode gradually hinders the oxygen reduction reaction (ORR) process, which usually leads to the premature death of the Li-O 2 battery. In this work, by introducing the molecular sieve powder into the ether electrolyte, the Li-O 2 battery exhibits a largely improved discharge capacity (63 times) compared with the one in the absence of this inorganic oxide additive. Meanwhile, XRD and SEM results qualitatively demonstrate the generation of the toroid Li 2 O 2 as the dominated discharge products, and the chemical titration quantifies a higher yield of the Li 2 O 2 with the presence of the molecular sieve additive. The addition of the molecular sieve controls the amount of the free water in the electrolyte, which distinguishes the effect of the molecular sieve and the free water on the discharge process. Hence, a possible mechanism has been proposed that the adsorption of the molecular sieves toward the soluble lithium superoxides improves the disproportionation of the lithium superoxides and consequently enhances the solution-growth of the lithium peroxides in the low donor number ether electrolyte. In general, the application of the molecular sieve triggers further studies concerning the improvement of the discharge performance in the Li-O 2 battery by adding the inorganic additives.

Artificial Solid Electrolyte Interphase-Protected LixSi Nanoparticles: An Efficient and Stable Prelithiation Reagent for Lithium-Ion Batteries.

PubMed

Zhao, Jie; Lu, Zhenda; Wang, Haotian; Liu, Wei; Lee, Hyun-Wook; Yan, Kai; Zhuo, Denys; Lin, Dingchang; Liu, Nian; Cui, Yi

2015-07-08

Prelithiation is an important strategy to compensate for lithium loss in lithium-ion batteries, particularly during the formation of the solid electrolyte interphase (SEI) from reduced electrolytes in the first charging cycle. We recently demonstrated that LixSi nanoparticles (NPs) synthesized by thermal alloying can serve as a high-capacity prelithiation reagent, although their chemical stability in the battery processing environment remained to be improved. Here we successfully developed a surface modification method to enhance the stability of LixSi NPs by exploiting the reduction of 1-fluorodecane on the LixSi surface to form a continuous and dense coating through a reaction process similar to SEI formation. The coating, consisting of LiF and lithium alkyl carbonate with long hydrophobic carbon chains, serves as an effective passivation layer in the ambient environment. Remarkably, artificial-SEI-protected LixSi NPs show a high prelithiation capacity of 2100 mA h g(-1) with negligible capacity decay in dry air after 5 days and maintain a high capacity of 1600 mA h g(-1) in humid air (∼10% relative humidity). Silicon, tin, and graphite were successfully prelithiated with these NPs to eliminate the irreversible first-cycle capacity loss. The use of prelithiation reagents offers a new approach to realize next-generation high-energy-density lithium-ion batteries.

Promoter Effects of Alkali Metal Cations on the Electrochemical Reduction of Carbon Dioxide

DOE PAGES

Resasco, Joaquin; Chen, Leanne D.; Clark, Ezra; ...

2017-07-24

The electrochemical reduction of CO 2 is known to be influenced by the identity of the alkali metal cation in the electrolyte; however, a satisfactory explanation for this phenomenon has not been developed. Here we present the results of experimental and theoretical studies aimed at elucidating the effects of electrolyte cation size on the intrinsic activity and selectivity of metal catalysts for the reduction of CO 2. Experiments were conducted under conditions where the influence of electrolyte polarization is minimal in order to show that cation size affects the intrinsic rates of formation of certain reaction products, most notably formore » HCOO –, C 2H 4, and C 2H 5OH over Cu(100)- and Cu(111)-oriented thin films, and for CO and HCOO– over polycrystalline Ag and Sn. Interpretation of the findings for CO 2 reduction was informed by studies of the reduction of glyoxal and CO, key intermediates along the reaction pathway to final products. Density functional theory calculations show that the alkali metal cations influence the distribution of products formed as a consequence of electrostatic interactions between solvated cations present at the outer Helmholtz plane and adsorbed species having large dipole moments. As a result, the observed trends in activity with cation size are attributed to an increase in the concentration of cations at the outer Helmholtz plane with increasing cation size.« less

Promoter Effects of Alkali Metal Cations on the Electrochemical Reduction of Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Resasco, Joaquin; Chen, Leanne D.; Clark, Ezra

The electrochemical reduction of CO 2 is known to be influenced by the identity of the alkali metal cation in the electrolyte; however, a satisfactory explanation for this phenomenon has not been developed. Here we present the results of experimental and theoretical studies aimed at elucidating the effects of electrolyte cation size on the intrinsic activity and selectivity of metal catalysts for the reduction of CO 2. Experiments were conducted under conditions where the influence of electrolyte polarization is minimal in order to show that cation size affects the intrinsic rates of formation of certain reaction products, most notably formore » HCOO –, C 2H 4, and C 2H 5OH over Cu(100)- and Cu(111)-oriented thin films, and for CO and HCOO– over polycrystalline Ag and Sn. Interpretation of the findings for CO 2 reduction was informed by studies of the reduction of glyoxal and CO, key intermediates along the reaction pathway to final products. Density functional theory calculations show that the alkali metal cations influence the distribution of products formed as a consequence of electrostatic interactions between solvated cations present at the outer Helmholtz plane and adsorbed species having large dipole moments. As a result, the observed trends in activity with cation size are attributed to an increase in the concentration of cations at the outer Helmholtz plane with increasing cation size.« less

Reduction mechanisms of additives on Si anodes of Li-ion batteries.

PubMed

Martínez de la Hoz, Julibeth M; Balbuena, Perla B

2014-08-28

Solid-electrolyte interphase (SEI) layers are films deposited on the surface of Li-ion battery electrodes during battery charge and discharge processes. They are due to electrochemical instability of the electrolyte which causes electron transfer from (to) the anode (cathode) surfaces. The films could have a protective passivating role and therefore understanding the detailed reduction (oxidation) processes is essential. Here density functional theory and ab initio molecular dynamics simulations are used to investigate the reduction mechanisms of vinylene carbonate (VC) and fluoroethylene carbonate (FEC) on lithiated silicon surfaces. These species are frequently used as "additives" to improve the SEI properties. It is found that on lithiated Si anodes (with low to intermediate degrees of lithiation) VC may be reduced via a 2e(-) mechanism yielding an opened VC(2-) anion. At higher degrees of lithiation, such a species receives two extra electrons from the surface resulting in an adsorbed CO(2-)(ads) anion and a radical anion ˙OC2H2O(2-). Additionally, in agreement with experimental observations, it is shown that CO2 can be generated from reaction of VC with the CO3(2-)anion, a product of the reduction of the main solvent, ethylene carbonate (EC). On the other hand, FEC reduction on LixSiy surfaces is found to be independent of the degree of lithiation, and occurs through three mechanisms. One of them leads to an adsorbed VC(2-) anion upon release from the FEC molecule and adsorption on the surface of F(-) and one H atom. Thus in some cases, the reduction of FEC may lead to the exact same reduction products as that of VC, which explains similarities in SEI layers formed in the presence of these additives. However, FEC may be reduced via two other multi-electron transfer mechanisms that result in formation of either CO2(2-), F(-), and ˙CH2CHO(-) or CO(2-), F(-), and ˙OCH2CHO(-). These alternative reduction products may oligomerize and form SEI layers with different components than those formed in the presence of VC. In all cases, FEC reduction also leads to formation of LiF moieties on the anode surface, in agreement with reported experimental data. The crucial role of the surface in each of these mechanisms is thoroughly explained.

Reduction of Surface Errors over a Wide Range of Spatial Frequencies Using a Combination of Electrolytic In-Process Dressing Grinding and Magnetorheological Finishing

NASA Astrophysics Data System (ADS)

Kunimura, Shinsuke; Ohmori, Hitoshi

We present a rapid process for producing flat and smooth surfaces. In this technical note, a fabrication result of a carbon mirror is shown. Electrolytic in-process dressing (ELID) grinding with a metal bonded abrasive wheel, then a metal-resin bonded abrasive wheel, followed by a conductive rubber bonded abrasive wheel, and finally magnetorheological finishing (MRF) were performed as the first, second, third, and final steps, respectively in this process. Flatness over the whole surface was improved by performing the first and second steps. After the third step, peak to valley (PV) and root mean square (rms) values in an area of 0.72 x 0.54 mm2 on the surface were improved. These values were further improved after the final step, and a PV value of 10 nm and an rms value of 1 nm were obtained. Form errors and small surface irregularities such as surface waviness and micro roughness were efficiently reduced by performing ELID grinding using the above three kinds of abrasive wheels because of the high removal rate of ELID grinding, and residual small irregularities were reduced by short time MRF. This process makes it possible to produce flat and smooth surfaces in several hours.

Low temperature aluminum reduction cell using hollow cathode

DOEpatents

Brown, Craig W.; Frizzle, Patrick B.

2002-08-20

A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. A plurality of non-consumable anodes are disposed substantially vertically in the electrolyte along with a plurality of monolithic hollow cathodes. Each cathode has a top and bottom and the cathodes are disposed vertically in the electrolyte and the anodes and the cathodes are arranged in alternating relationship. Each of the cathodes is comprised of a first side facing a first opposing anode and a second side facing a second opposing anode. The first and second sides are joined by ends to form a reservoir in the hollow cathode for collecting aluminum therein deposited at the cathode.

Role of solvents on the oxygen reduction and evolution of rechargeable Li-O2 battery

NASA Astrophysics Data System (ADS)

Christy, Maria; Arul, Anupriya; Zahoor, Awan; Moon, Kwang Uk; Oh, Mi Young; Stephan, A. Manuel; Nahm, Kee Suk

2017-02-01

The choice of electrolyte solvent is expected to play a key role in influencing the lithium-oxygen battery performance. The electrochemical performances of three electrolytes composed of lithium bis (trifluoromethane sulfonyl) imide (LiTFSI) salt and different solvents namely, ethylene carbonate/propylene carbonate (EC/PC), tetra ethylene glycol dimethyl ether (TEGDME) and dimethyl sulfoxide (DMSO) are investigated by assembling lithium oxygen cells. The electrolyte composition significantly varied the specific capacity of the battery. The choice of electrolyte also influences the overpotential, cycle life, and rechargeability of the battery. Electrochemical impedance spectra, cyclic voltammetry, and chronoamperometry were utilized to determine the reversible reactions associated with the air cathode.

Effect of Hydrofluoroether Cosolvent Addition on Li Solvation in Acetonitrile-Based Solvate Electrolytes and Its Influence on S Reduction in a Li–S Battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

See, Kimberly A.; Wu, Heng -Liang; Lau, Kah Chun

Li-S batteries are a promising next-generation battery technology. Due to the formation of soluble polysulfides during cell operation, the electrolyte composition of the cell plays an active role in directing the formation and speciation of the soluble lithium polysulfides. Recently, new classes of electrolytes termed "solvates" that contain stoichiometric quantities of salt and solvent and form a liquid at room temperature have been explored due to their sparingly solvating properties with respect to polysulfides. The viscosity of the solvate electrolytes is understandably high limiting their viability; however, hydrofluoroether cosolvents, thought to be inert to the solvate structure itself, can bemore » introduced to reduce viscosity and enhance diffusion. Nazar and co-workers previously reported that addition of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) to the LiTFSI in acetonitrile solvate, (MeCN) 2-LiTFSI, results in enhanced capacity retention compared to the neat solvate. Here, we evaluate the effect of TTE addition on both the electrochemical behavior of the Li-S cell and the solvation structure of the (MeCN) 2-LiTFSI electrolyte. Contrary to previous suggestions, Raman and NMR spectroscopy coupled with ab initio molecular dynamics simulations show that TTE coordinates to Li + at the expense of MeCN coordination, thereby producing a higher content of free MeCN, a good polysulfide solvent, in the electrolyte. Furthermore, the electrolytes containing a higher free MeCN content facilitate faster polysulfide formation kinetics during the electrochemical reduction of S in a Li-S cell likely as a result of the solvation power of the free MeCN.« less

Effect of Hydrofluoroether Cosolvent Addition on Li Solvation in Acetonitrile-Based Solvate Electrolytes and Its Influence on S Reduction in a Li–S Battery

DOE PAGES

See, Kimberly A.; Wu, Heng -Liang; Lau, Kah Chun; ...

2016-11-16

Li-S batteries are a promising next-generation battery technology. Due to the formation of soluble polysulfides during cell operation, the electrolyte composition of the cell plays an active role in directing the formation and speciation of the soluble lithium polysulfides. Recently, new classes of electrolytes termed "solvates" that contain stoichiometric quantities of salt and solvent and form a liquid at room temperature have been explored due to their sparingly solvating properties with respect to polysulfides. The viscosity of the solvate electrolytes is understandably high limiting their viability; however, hydrofluoroether cosolvents, thought to be inert to the solvate structure itself, can bemore » introduced to reduce viscosity and enhance diffusion. Nazar and co-workers previously reported that addition of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) to the LiTFSI in acetonitrile solvate, (MeCN) 2-LiTFSI, results in enhanced capacity retention compared to the neat solvate. Here, we evaluate the effect of TTE addition on both the electrochemical behavior of the Li-S cell and the solvation structure of the (MeCN) 2-LiTFSI electrolyte. Contrary to previous suggestions, Raman and NMR spectroscopy coupled with ab initio molecular dynamics simulations show that TTE coordinates to Li + at the expense of MeCN coordination, thereby producing a higher content of free MeCN, a good polysulfide solvent, in the electrolyte. Furthermore, the electrolytes containing a higher free MeCN content facilitate faster polysulfide formation kinetics during the electrochemical reduction of S in a Li-S cell likely as a result of the solvation power of the free MeCN.« less

Effect of Hydrofluoroether Cosolvent Addition on Li Solvation in Acetonitrile-Based Solvate Electrolytes and Its Influence on S Reduction in a Li-S Battery.

PubMed

See, Kimberly A; Wu, Heng-Liang; Lau, Kah Chun; Shin, Minjeong; Cheng, Lei; Balasubramanian, Mahalingam; Gallagher, Kevin G; Curtiss, Larry A; Gewirth, Andrew A

2016-12-21

Li-S batteries are a promising next-generation battery technology. Due to the formation of soluble polysulfides during cell operation, the electrolyte composition of the cell plays an active role in directing the formation and speciation of the soluble lithium polysulfides. Recently, new classes of electrolytes termed "solvates" that contain stoichiometric quantities of salt and solvent and form a liquid at room temperature have been explored due to their sparingly solvating properties with respect to polysulfides. The viscosity of the solvate electrolytes is understandably high limiting their viability; however, hydrofluoroether cosolvents, thought to be inert to the solvate structure itself, can be introduced to reduce viscosity and enhance diffusion. Nazar and co-workers previously reported that addition of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) to the LiTFSI in acetonitrile solvate, (MeCN) 2 -LiTFSI, results in enhanced capacity retention compared to the neat solvate. Here, we evaluate the effect of TTE addition on both the electrochemical behavior of the Li-S cell and the solvation structure of the (MeCN) 2 -LiTFSI electrolyte. Contrary to previous suggestions, Raman and NMR spectroscopy coupled with ab initio molecular dynamics simulations show that TTE coordinates to Li + at the expense of MeCN coordination, thereby producing a higher content of free MeCN, a good polysulfide solvent, in the electrolyte. The electrolytes containing a higher free MeCN content facilitate faster polysulfide formation kinetics during the electrochemical reduction of S in a Li-S cell likely as a result of the solvation power of the free MeCN.

The Electrochemical Performance of Silicon Nanoparticles in Concentrated Electrolyte.

PubMed

Chang, Zeng-Hua; Wang, Jian-Tao; Wu, Zhao-Hui; Gao, Min; Wu, Shuai-Jin; Lu, Shi-Gang

2018-06-11

Silicon is a promising material for anodes in energy-storage devices. However, excessive growth of a solid-electrolyte interphase (SEI) caused by the severe volume change during the (de)lithiation processes leads to dramatic capacity fading. Here, we report a super-concentrated electrolyte composed of lithium bis(fluorosulfonyl)imide (LiFSI) and propylene carbonate (PC) with a molar ratio of 1:2 to improve the cycling performance of silicon nanoparticles (SiNPs). The SiNP electrode shows a remarkably improved cycling performance with an initial delithiation capacity of approximately 3000 mAh g -1 and a capacity of approximately 2000 mAh g -1 after 100 cycles, exhibiting about 6.8 times higher capacity than the cells with dilute electrolyte LiFSI-(PC) 8 . Raman spectra reveal that most of the PC solvent and FSI anions are complexed by Li + to form a specific solution structure like a fluid polymeric network. The reduction of FSI anions starts to play an important role owing to the increased concentration of contact ion pairs (CIPs) or aggregates (AGGs), which contribute to the formation of a more mechanically robust and chemically stable complex SEI layer. The complex SEI layer can effectively suppress the morphology evolution of silicon particles and self-limit the excessive growth, which mitigates the crack propagation of the silicon electrode and the deterioration of the kinetics. This study will provide a new direction for screening cycling-stable electrolytes for silicon-based electrodes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Designer interphases for the lithium-oxygen electrochemical cell

PubMed Central

Choudhury, Snehashis; Wan, Charles Tai-Chieh; Al Sadat, Wajdi I.; Tu, Zhengyuan; Lau, Sampson; Zachman, Michael J.; Kourkoutis, Lena F.; Archer, Lynden A.

2017-01-01

An electrochemical cell based on the reversible oxygen reduction reaction: 2Li+ + 2e− + O2 ↔ Li2O2, provides among the most energy dense platforms for portable electrical energy storage. Such Lithium-Oxygen (Li-O2) cells offer specific energies competitive with fossil fuels and are considered promising for electrified transportation. Multiple, fundamental challenges with the cathode, anode, and electrolyte have limited practical interest in Li-O2 cells because these problems lead to as many practical shortcomings, including poor rechargeability, high overpotentials, and specific energies well below theoretical expectations. We create and study in-situ formation of solid-electrolyte interphases (SEIs) based on bromide ionomers tethered to a Li anode that take advantage of three powerful processes for overcoming the most stubborn of these challenges. The ionomer SEIs are shown to protect the Li anode against parasitic reactions and also stabilize Li electrodeposition during cell recharge. Bromine species liberated during the anchoring reaction also function as redox mediators at the cathode, reducing the charge overpotential. Finally, the ionomer SEI forms a stable interphase with Li, which protects the metal in high Gutmann donor number liquid electrolytes. Such electrolytes have been reported to exhibit rare stability against nucleophilic attack by Li2O2 and other cathode reaction intermediates, but also react spontaneously with Li metal anodes. We conclude that rationally designed SEIs able to regulate transport of matter and ions at the electrolyte/anode interface provide a promising platform for addressing three major technical barriers to practical Li-O2 cells. PMID:28439557

Composition of highly concentrated silicate electrolytes and ultrasound influencing the plasma electrolytic oxidation of magnesium

NASA Astrophysics Data System (ADS)

Simchen, F.; Rymer, L.-M.; Sieber, M.; Lampke, T.

2017-03-01

Magnesium and its alloys are increasingly in use as lightweight construction materials. However, their inappropriate corrosion and wear resistance often prevent their direct practical use. The plasma electrolytic oxidation (PEO) is a promising, environmentally friendly method to improve the surface characteristics of magnesium materials by the formation of oxide coatings. These PEO layers contain components of the applied electrolyte and can be shifted in their composition by increasing the concentration of the electrolyte constituents. Therefore, in contrast to the use of conventional low concentrated electrolytes, the process results in more stable protective coatings, in which electrolyte species are the dominating constitutes. In the present work, the influence of the composition of highly concentrated alkaline silicate electrolytes with additives of phosphate and glycerol on the quality of PEO layers on the magnesium alloy AZ31 was examined. The effect of ultrasound coupled into the electrolyte bath was also considered. The process was monitored by recording the electrical process variables with a transient recorder and by observation of the discharge phenomena on the sample surface with a camera. The study was conducted on the basis of a design of experiments. The effects of the process parameter variation are considered with regard to the coatings thickness, hardness and corrosion resistance. Information about the statistical significance of the effects of the parameters on the considered properties is obtained by an analysis of variance (ANOVA).

Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

NASA Astrophysics Data System (ADS)

Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

2018-02-01

In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

A highly efficient electrocatalyst for oxygen reduction reaction: phosphorus and nitrogen co-doped hierarchically ordered porous carbon derived from an iron-functionalized polymer

NASA Astrophysics Data System (ADS)

Deng, Chengwei; Zhong, Hexiang; Li, Xianfeng; Yao, Lan; Zhang, Huamin

2016-01-01

Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm2 g-1) and a pore volume of 1.14 cm3 g-1. Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic electrolytes, thus making the catalyst promising for fuel cells. The correlations between the unique pore structure and the nitrogen and phosphorus configuration of the catalysts with high catalytic activity are thoroughly investigated.Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm2 g-1) and a pore volume of 1.14 cm3 g-1. Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic electrolytes, thus making the catalyst promising for fuel cells. The correlations between the unique pore structure and the nitrogen and phosphorus configuration of the catalysts with high catalytic activity are thoroughly investigated. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06749a

Electrochemical performance evaluations and safety investigations of pentafluoro(phenoxy)cyclotriphosphazene as a flame retardant electrolyte additive for application in lithium ion battery systems using a newly designed apparatus for improved self-extinguishing time measurements

NASA Astrophysics Data System (ADS)

Dagger, Tim; Lürenbaum, Constantin; Schappacher, Falko M.; Winter, Martin

2017-02-01

A modified self-extinguishing time (SET) device which enhances the reproducibility of the results is presented. Pentafluoro(phenoxy)cyclotriphosphazene (FPPN) is investigated as flame retardant electrolyte additive for lithium ion batteries (LIBs) in terms of thermal stability and electrochemical performance. SET measurements and adiabatic reaction calorimetry are applied to determine the flammability and the reactivity of a standard LIB electrolyte containing 5% FPPN. The results reveal that the additive-containing electrolyte is nonflammable for 10 s whereas the commercially available reference electrolyte inflames instantaneously after 1 s of ignition. The onset temperature of the safety enhanced electrolyte is delayed by ≈ 21 °C. Compatibility tests in half cells show that the electrolyte is reductively stable while the cyclic voltammogram indicates oxidative decomposition during the first cycle. Cycling experiments in full cells show improved cycling performance and rate capability, which can be attributed to cathode passivation during the first cycle. Post-mortem analysis of the electrolyte by gas chromatography-mass spectrometry confirms the presence of the additive in high amounts after 501 cycles which ensures enhanced safety of the electrolyte. The investigations present FPPN as stable electrolyte additive that improves the intrinsic safety of the electrolyte and its cycling performance at the same time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allcorn, Eric

Lithium-ion battery safety is a critical issue in the adoption of the chemistry to larger scale applications such as transportation and stationary storage. One of the critical components impacting the safety of lithium-ion batteries is their use of highly flammable organic electrolytes. In this work, brominated flame retardants (BFR’s) – an existing class of flame retardant materials – are incorporated as additives to lithium-ion battery electrolytes with the intention to reduce the electrolyte flammability and thereby improve safety. There are a few critical needs for a successful electrolyte additive: solubility in the electrolyte, electrochemical stability over the range of batterymore » operation, and minimal detrimental effects on battery performance. Those detrimental effects can take the form of electrolyte specific impacts, such as a reduction in conductivity, or electrode impacts, such as SEI-layer modification or chemical instability to the active material. In addition to these needs, the electrolyte additive also needs to achieve its intended purpose, which in this case is to reduce the flammability of the electrolyte. For the work conducted as part of this SPP agreement three separate BFR materials were provided by Albemarle to be tested by Sandia as additives in a traditional lithium-ion battery electrolyte. The provided BFR materials were tribromo-neopentyl alcohol, tetrabromo bisphenol A, and tribromoethylene. These materials were incorporated as separate 4 wt.% additives into a traditional lithium-ion battery electrolyte and compared to said traditional electrolyte, designated Gen2.« less

Liquid-Feed Methanol Fuel Cell With Membrane Electrolyte

NASA Technical Reports Server (NTRS)

Surampudi, Subbarao; Narayanan, S. R.; Halpert, Gerald; Frank, Harvey; Vamos, Eugene

1995-01-01

Fuel cell generates electricity from direct liquid feed stream of methanol/water solution circulated in contact with anode, plus direct gaseous feed stream of air or oxygen in contact with cathode. Advantages include relative simplicity and elimination of corrosive electrolytic solutions. Offers potential for reductions in size, weight, and complexity, and for increases in safety of fuel-cell systems.

Process for producing elements from a fused bath using a metal strap and ceramic electrode body nonconsumable electrode assembly

DOEpatents

Byrne, Stephen C.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a ceramic electrode body and a metal subassembly of a metal conductor rod and at least one metal strap affixed to an end of the rod with opposing portions extending radially outwardly from the rod axis and having the ends of the strap attached to the electrode body.

Application of electrolytic in-process dressing for high-efficiency grinding of ceramic parts. Research activities 1995--96

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bandyopadhyay, B.P.

1997-02-01

The application of Electrolytic In-Process Dressing (ELID) for highly efficient and stable grinding of ceramic parts is discussed. This research was performed at the Institute of Physical and Chemical Research (RIKEN), Tokyo, Japan, June 1995 through August 1995. Experiments were conducted using a vertical machining center. The silicon nitride work material, of Japanese manufacture and supplied in the form of a rectangular block, was clamped to a vice which was firmly fixed on the base of a strain gage dynamometer. The dynamometer was clamped on the machining center table. Reciprocating grinding was performed with a flat-faced diamond grinding wheel. Themore » output from the dynamometer was recorded with a data acquisition system and the normal component of the force was monitored. Experiments were carried out under various cutting conditions, different ELID conditions, and various grinding wheel bonds types. Rough grinding wheels of grit sizes {number_sign}170 and {number_sign}140 were used in the experiments. Compared to conventional grinding, there was a significant reduction in grinding force with ELID grinding. Therefore, ELID grinding can be recommended for high material removal rate grinding, low rigidity machines, and low rigidity workpieces. Compared to normal grinding, a reduction in grinding ratio was observed when ELID grinding was performed. A negative aspect of the process, this reduced G-ratio derives from bond erosion and can be improved somewhat by adjustments in the ELID current. The results of this investigation are discussed in detail in this report.« less

Effects of shielding coatings on the anode shaping process during counter-rotating electrochemical machining

NASA Astrophysics Data System (ADS)

Wang, Dengyong; Zhu, Zengwei; Wang, Ningfeng; Zhu, Di

2016-09-01

Electrochemical machining (ECM) has been widely used in the aerospace, automotive, defense and medical industries for its many advantages over traditional machining methods. However, the machining accuracy in ECM is to a great extent limited by the stray corrosion of the unwanted material removal. Many attempts have been made to improve the ECM accuracy, such as the use of a pulse power, passivating electrolytes and auxiliary electrodes. However, they are sometimes insufficient for the reduction of the stray removal and have their limitations in many cases. To solve the stray corrosion problem in CRECM, insulating and conductive coatings are respectively used. The different implement processes of the two kinds of coatings are introduced. The effects of the two kinds of shielding coatings on the anode shaping process are investigated. Numerical simulations and experiments are conducted for the comparison of the two coatings. The simulation and experimental results show that both the two kinds of coatings are valid for the reduction of stray corrosion on the top surface of the convex structure. However, for insulating coating, the convex sidewall becomes concave when the height of the convex structure is over 1.26 mm. In addition, it is easy to peel off by the high-speed electrolyte. In contrast, the conductive coating has a strong adhesion, and can be well reserved during the whole machining process. The convex structure fabricated by using a conductive iron coating layer presents a favorable sidewall profile. It is concluded that the conductive coating is more effective for the improvement of the machining quality in CRECM. The proposed shielding coatings can also be employed to reduce the stray corrosion in other schemes of ECM.

Oxygen solubility and transport in Li–air battery electrolytes: Establishing criteria and strategies for electrolyte design

DOE PAGES

Gittleson, Forrest S.; Jones, Reese E.; Ward, Donald K.; ...

2017-02-15

Li–air or Li–oxygen batteries promise significantly higher energies than existing commercial battery technologies, yet their development has been hindered by a lack of suitable electrolytes. In this article, we evaluate the physical properties of varied electrolyte compositions to form generalized criteria for electrolyte design. We show that oxygen transport through non-aqueous electrolytes has a critical impact on the discharge rate and capacity of Li–air batteries. Through experiments and molecular dynamics simulations, we highlight that the choice of salt species and concentration have an outsized influence on oxygen solubility, while solvent choice is the major influence on oxygen diffusivity. The stabilitymore » of superoxide reaction intermediates, key to the oxygen reduction mechanism, is also affected by variations in salt concentration and the choice of solvent. The importance of reactant transport is confirmed through Li–air cell discharge, which demonstrates good agreement between the observed and calculated mass transport-limited currents. Furthermore, these results showcase the impact of electrolyte composition on transport in metal–air batteries and provide guiding principles and simulation-based tools for future electrolyte design.« less

Kinetic factors determining conducting filament formation in solid polymer electrolyte based planar devices

NASA Astrophysics Data System (ADS)

Krishnan, Karthik; Aono, Masakazu; Tsuruoka, Tohru

2016-07-01

Resistive switching characteristics and conducting filament formation dynamics in solid polymer electrolyte (SPE) based planar-type atomic switches, with opposing active Ag and inert Pt electrodes, have been investigated by optimizing the device configuration and experimental parameters such as the gap distance between the electrodes, the salt inclusion in the polymer matrix, and the compliance current applied in current-voltage measurements. The high ionic conductivities of SPE enabled us to make scanning electron microscopy observations of the filament formation processes in the sub-micrometer to micrometer ranges. It was found that switching behaviour and filament growth morphology depend strongly on several kinetic factors, such as the redox reaction rate at the electrode-polymer interfaces, ion mobility in the polymer matrix, electric field strength, and the reduction sites for precipitation. Different filament formations, resulting from unidirectional and dendritic growth behaviours, can be controlled by tuning specified parameters, which in turn improves the stability and performance of SPE-based devices.Resistive switching characteristics and conducting filament formation dynamics in solid polymer electrolyte (SPE) based planar-type atomic switches, with opposing active Ag and inert Pt electrodes, have been investigated by optimizing the device configuration and experimental parameters such as the gap distance between the electrodes, the salt inclusion in the polymer matrix, and the compliance current applied in current-voltage measurements. The high ionic conductivities of SPE enabled us to make scanning electron microscopy observations of the filament formation processes in the sub-micrometer to micrometer ranges. It was found that switching behaviour and filament growth morphology depend strongly on several kinetic factors, such as the redox reaction rate at the electrode-polymer interfaces, ion mobility in the polymer matrix, electric field strength, and the reduction sites for precipitation. Different filament formations, resulting from unidirectional and dendritic growth behaviours, can be controlled by tuning specified parameters, which in turn improves the stability and performance of SPE-based devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00569a

Lithium dendrite and solid electrolyte interphase investigation using OsO4

NASA Astrophysics Data System (ADS)

Zier, Martin; Scheiba, Frieder; Oswald, Steffen; Thomas, Jürgen; Goers, Dietrich; Scherer, Torsten; Klose, Markus; Ehrenberg, Helmut; Eckert, Jürgen

2014-11-01

Osmium tetroxide (OsO4) staining, commonly used to enhance scattering contrast in electron microscopy of biologic tissue and polymer blends, has been adopted for studies of graphite anodes in lithium-ion batteries. OsO4 shows a coordinated reaction with components of the solid electrolyte interphase (SEI) and lithium dendrites, thereby increasing material contrast for scanning electron microscopy investigations. Utilizing the high affinity of lithium metal to react with osmium tetroxide it was possible to localize even small lithium deposits on graphite electrodes. In spite of their reaction with the OsO4 fume, the lithium dendrite morphology remains almost untouched by the staining procedure, offering information on the dendrite growth process. Correlating the quantity of osmium detected with the amount of residual ("dead") lithium of a discharged electrode, it was possible to obtain a practical measure for lithium plating and stripping efficiencies. EDX mappings allowed for a localization of electrochemically stripped lithium dendrites by their residual stained SEI shells. Cross sections, prepared by focused ion beam (FIB) of cycled graphite electrodes treated with OsO4, revealed important information about deposition and distribution of metallic lithium and the electrolyte reduction layer across the electrode.

Electrochemical method of producing eutectic uranium alloy and apparatus

DOEpatents

Horton, James A.; Hayden, H. Wayne

1995-01-01

An apparatus and method for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride. The method of the invention produces an eutectic uranium alloy by creating an electrolyte reservoir defined by a container comprising an anode, placing an electrolyte in the reservoir, the electrolyte comprising a chlorine or fluorine containing salt and uranium chloride in molten form, positioning a cathode in the reservoir where the cathode comprises a metal capable of forming an uranium alloy having a melting point less than the melting point of pure uranium, and applying a current between the cathode and the anode.

Electrochemical method of producing eutectic uranium alloy and apparatus

DOEpatents

Horton, J.A.; Hayden, H.W.

1995-01-10

An apparatus and method are disclosed for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride. The method of the invention produces an eutectic uranium alloy by creating an electrolyte reservoir defined by a container comprising an anode, placing an electrolyte in the reservoir, the electrolyte comprising a chlorine or fluorine containing salt and uranium chloride in molten form, positioning a cathode in the reservoir where the cathode comprises a metal capable of forming an uranium alloy having a melting point less than the melting point of pure uranium, and applying a current between the cathode and the anode. 2 figures.

The Effect of Fluoroethylene Carbonate as an Additive on the Solid Electrolyte Interphase on Silicon Lithium-Ion Electrodes

DOE PAGES

Schroder, Kjell; Li, Juchuan; Dudney, Nancy J.; ...

2015-08-03

Fluoroethylene carbonate (FEC) has become a standard electrolyte additive for use with silicon negative electrodes, but how FEC affects solid electrolyte interphase (SEI) formation on the silicon anode’s surface is still not well understood. Herein, SEI formed from LiPF6-based carbonate electrolytes, with and without FEC, were investigated on 50 nm thick amorphous silicon thin film electrodes to understand the role of FEC on silicon electrode surface reactions. In contrast to previous work, anhydrous and anoxic techniques were used to prevent air and moisture contamination of prepared SEI films. This allowed for accurate characterization of the SEI structure and composition bymore » X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry depth profiling. These results show that FEC reduction leads to fluoride ion and LiF formation, consistent with previous computational and experimental results. Surprisingly, we also find that these species decrease lithium-ion solubility and increase the reactivity of the silicon surface. We conclude that the effectiveness of FEC at improving the Coulombic efficiency and capacity retention is due to fluoride ion formation from reduction of the electrolyte, which leads to the chemical attack of any silicon-oxide surface passivation layers and the formation of a kinetically stable SEI comprising predominately lithium fluoride and lithium oxide.« less

Electrocatalysts for oxygen electrodes in fuel cells and water electrolyzers for space applications

NASA Technical Reports Server (NTRS)

Prakash, Jai; Tryk, Donald; Yeager, Ernest

1989-01-01

In most instances separate electrocatalysts are needed to promote the reduction of O2 in the fuel cell mode and to generate O2 in the energy storage-water electrolysis mode in aqueous electrochemical systems operating at low and moderate temperatures (T greater than or equal to 200 C). Interesting exceptions are the lead and bismuth ruthenate pyrochlores in alkaline electrolytes. These catalysts on high area carbon supports have high catalytic activity for both O2 reduction and generation (1,2). Rotating ring-disk electrode measurements provide evidence that the O2 reduction proceeds by a parallel four-electron pathway. The ruthenates can also be used as self-supported catalysts to avoid the problems associated with carbon oxidation, but the electrode performance so far achieved in the research at Case Western Reserve University (CWRU) is considerably less. At the potentials involved in the anodic mode the ruthenate pyrochlores have substantial equilibrium solubility in concentrated alkaline electrolyte. This results in the loss of catalyst into the bulk solution and a decline in catalytic activity. Furthermore, the hydrogen generation counter electrode may become contaminated with reduction products from the pyrochlores (lead, ruthenium). A possible approach to this problem is to immobilize the pyrochlore catalyst within an ionic-conducting solid polymer, which would replace the fluid electrolyte within the porous gas diffusion O2 electrode. For bulk alkaline electrolyte, an anion-exchange polymer is needed with a transference number close to unity for the Oh(-) ion. Preliminary short-term measurements with lead ruthenates using a commercially available partially-fluorinated anion-exchange membrane as an overlayer on the porous gas-fed electrode indicate lower anodic polarization and virtually unchanged cathodic polarization.

Effects of electrolytes on redox potentials through ion pairing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bird, Matthew J.; Iyoda, Tomokazu; Bonura, Nicholas

Here, reduction potentials have been determined for two molecules, benzophenone (BzPh) and perylene (Per), effectively in the complete absence of electrolyte as well as in the presence of three different supporting electrolytes in the moderately polar solvent THF. A description of how this can be so, and qualifications, are described in the discussion section. The primary tool in this work, pulse radiolysis, measures electron transfer (ET) equilibria in solution to obtain differences in redox potentials. Voltammetry measures redox potentials by establishing ET equilibria at electrodes, but electrolytes are needed for current flow. Results here show that without electrolyte the redoxmore » potentials were 100–451 mV more negative than those with 100 mM electrolyte. These changes depended both on the molecule and the electrolyte. In THF the dominant contributor to stabilization of radical anions by electrolyte was ion pairing. An equation was derived to give changes in redox potentials when electrolyte is added in terms of ion pair dissociation constants and activity coefficients. Definite values were determined for energetics, ΔG d°, of ion pairing. Values of ΔG d° for pairs with TBA + give some doubt that it is a “weakly-coordinating cation.” Computations with DFT methods were moderately successful at describing the ion paring energies.« less

Mechanistic Study of Electrolyte Additives to Stabilize High-Voltage Cathode-Electrolyte Interface in Lithium-Ion Batteries.

PubMed

Gao, Han; Maglia, Filippo; Lamp, Peter; Amine, Khalil; Chen, Zonghai

2017-12-27

Current developments of electrolyte additives to stabilize electrode-electrolyte interface in lithium-ion batteries highly rely on a trial-and-error search, which involves repetitive testing and intensive amount of resources. The lack of understandings on the fundamental protection mechanisms of the additives significantly increases the difficulty for the transformational development of new additives. In this study, we investigated two types of individual protection routes to build a robust cathode-electrolyte interphase at high potentials: (i) a direct reduction in the catalytic decomposition of the electrolyte solvent; and (ii) formation of a "corrosion inhibitor film" that prevents severely attack and passivation from protons that generated from the solvent oxidation, even the decomposition of solvent cannot be mitigated. Effect of two exemplary electrolyte additives, lithium difluoro(oxalato)borate (LiDFOB) and 3-hexylthiophene (3HT), on LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC 622) cathode were investigated to validate our hypothesis. It is demonstrated that understandings of both electrolyte additives and solvent are essential and careful balance between the cathode protection mechanism of additives and their side effects is critical to obtain optimum results. More importantly, this study opens up new directions of rational design of functional electrolyte additives for the next-generation high-energy-density lithium-ion chemistries.

Effects of electrolytes on redox potentials through ion pairing

DOE PAGES

Bird, Matthew J.; Iyoda, Tomokazu; Bonura, Nicholas; ...

2017-09-21

Here, reduction potentials have been determined for two molecules, benzophenone (BzPh) and perylene (Per), effectively in the complete absence of electrolyte as well as in the presence of three different supporting electrolytes in the moderately polar solvent THF. A description of how this can be so, and qualifications, are described in the discussion section. The primary tool in this work, pulse radiolysis, measures electron transfer (ET) equilibria in solution to obtain differences in redox potentials. Voltammetry measures redox potentials by establishing ET equilibria at electrodes, but electrolytes are needed for current flow. Results here show that without electrolyte the redoxmore » potentials were 100–451 mV more negative than those with 100 mM electrolyte. These changes depended both on the molecule and the electrolyte. In THF the dominant contributor to stabilization of radical anions by electrolyte was ion pairing. An equation was derived to give changes in redox potentials when electrolyte is added in terms of ion pair dissociation constants and activity coefficients. Definite values were determined for energetics, ΔG d°, of ion pairing. Values of ΔG d° for pairs with TBA + give some doubt that it is a “weakly-coordinating cation.” Computations with DFT methods were moderately successful at describing the ion paring energies.« less

Effects of common groundwater ions on chromate removal by magnetite: importance of chromate adsorption.

PubMed

Meena, Amanda H; Arai, Yuji

2016-01-01

Reductive precipitation of hexavalent chromium (Cr(VI)) with magnetite is a well-known Cr(VI) remediation method to improve water quality. The rapid (

Edge-selenated graphene nanoplatelets as durable metal-free catalysts for iodine reduction reaction in dye-sensitized solar cells

PubMed Central

Ju, Myung Jong; Jeon, In-Yup; Kim, Hong Mo; Choi, Ji Il; Jung, Sun-Min; Seo, Jeong-Min; Choi, In Taek; Kang, Sung Ho; Kim, Han Seul; Noh, Min Jong; Lee, Jae-Joon; Jeong, Hu Young; Kim, Hwan Kyu; Kim, Yong-Hoon; Baek, Jong-Beom

2016-01-01

Metal-free carbon-based electrocatalysts for dye-sensitized solar cells (DSSCs) are sufficiently active in Co(II)/Co(III) electrolytes but are not satisfactory in the most commonly used iodide/triiodide (I−/I3−) electrolytes. Thus, developing active and stable metal-free electrocatalysts in both electrolytes is one of the most important issues in DSSC research. We report the synthesis of edge-selenated graphene nanoplatelets (SeGnPs) prepared by a simple mechanochemical reaction between graphite and selenium (Se) powders, and their application to the counter electrode (CE) for DSSCs in both I−/I3− and Co(II)/Co(III) electrolytes. The edge-selective doping and the preservation of the pristine graphene basal plane in the SeGnPs were confirmed by various analytical techniques, including atomic-resolution transmission electron microscopy. Tested as the DSSC CE in both Co(bpy)32+/3+ (bpy = 2,2′-bipyridine) and I−/I3− electrolytes, the SeGnP-CEs exhibited outstanding electrocatalytic performance with ultimately high stability. The SeGnP-CE–based DSSCs displayed a higher photovoltaic performance than did the Pt-CE–based DSSCs in both SM315 sensitizer with Co(bpy)32+/3+ and N719 sensitizer with I−/I3− electrolytes. Furthermore, the I3− reduction mechanism, which has not been fully understood in carbon-based CE materials to date, was clarified by an electrochemical kinetics study combined with density functional theory and nonequilibrium Green’s function calculations. PMID:27386557

Feed-back between geriatric syndromes: general system theory in geriatrics.

PubMed

Musso, Carlos G; Núñez, Juan F Macías

2006-01-01

Geriatrics has described three entities: confusional syndrome, incontinente and gait disorders, calling them geriatric giants. Aging process also induces changes in renal physiology such as glomerular filtration rate reduction, and alteration in water and electrolytes handling. These ageing renal changes have been named as nephrogeriatric giants. These two groups of giants, geriatric and nephrogeriatric, can predispose and potentiate each other leading old people to fatal outcomes. These phenomenon of feed-back between these geriatric syndromes has its roots in the loss of complexity that the ageing process has. Complexity means that all the body systems work harmoniously. The process of senescence weakens this coordination among systems undermining complexity and making the old person frail.

Electrochemically driven three-phase interlines into insulator compounds: electroreduction of solid SiO2 in molten CaCl2.

PubMed

Xiao, Wei; Jin, Xianbo; Deng, Yuan; Wang, Dihua; Hu, Xiaohong; Chen, George Z

2006-08-11

The electrochemical reduction of solid SiO2 (quartz) to Si is studied in molten CaCl2 at 1173 K. Experimental observations are compared and agree well with a novel penetration model in relation with electrochemistry at the dynamic conductor|insulator|electrolyte three-phase interlines. The findings show that the reduction of a cylindrical quartz pellet at certain potentials is mainly determined by the diffusion of the O(2-) ions and also the ohmic polarisation in the reduction-generated porous silicon layer. The reduction rate increases with the overpotential to a maximum after which the process is retarded, most likely due to precipitation of CaO in the reaction region (cathodic passivation). Data are reported on the reduction rate, current efficiency and energy consumption during the electroreduction of quartz under potentiostatic conditions. These theoretical and experimental findings form the basis for an in-depth discussion on the optimisation of the electroreduction method for the production of silicon.

Reduced temperature aluminum production in an electrolytic cell having an inert anode

DOEpatents

Dawless, Robert K.; Ray, Siba P.; Hosler, Robert B.; Kozarek, Robert L.; LaCamera, Alfred F.

2000-01-01

Aluminum is produced by electrolytic reduction of alumina in a cell having a cathode, an inert anode and a molten salt bath containing metal fluorides and alumina. The inert anode preferably contains copper, silver and oxides of iron and nickel. Reducing the molten salt bath temperature to about 900-950.degree. C. lowers corrosion on the inert anode constituents.

Diffusion welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Vasudevan, Asuri K.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor diffusion welded to a portion of a ceramic electrode body having a level of free metal or metal alloy sufficient to effect a metal bond.

Interlocking wettable ceramic tiles

DOEpatents

Tabereaux, Jr., Alton T.; Fredrickson, Guy L.; Groat, Eric; Mroz, Thomas; Ulicny, Alan; Walker, Mark F.

2005-03-08

An electrolytic cell for the reduction of aluminum having a layer of interlocking cathode tiles positioned on a cathode block. Each tile includes a main body and a vertical restraining member to prevent movement of the tiles away from the cathode block during operation of the cell. The anode of the electrolytic cell may be positioned about 1 inch from the interlocking cathode tiles.

Chemically rechargeable battery

NASA Technical Reports Server (NTRS)

Graf, James E. (Inventor); Rowlette, John J. (Inventor)

1984-01-01

Batteries (50) containing oxidized, discharged metal electrodes such as an iron-air battery are charged by removing and storing electrolyte in a reservoir (98), pumping fluid reductant such as formalin (aqueous formaldehyde) from a storage tank (106) into the battery in contact with the surfaces of the electrodes. After sufficient iron hydroxide has been reduced to iron, the spent reductant is drained, the electrodes rinsed with water from rinse tank (102) and then the electrolyte in the reservoir (106) is returned to the battery. The battery can be slowly electrically charged when in overnight storage but can be quickly charged in about 10 minutes by the chemical procedure of the invention.

High Performance of Supercapacitor from PEDOT:PSS Electrode and Redox Iodide Ion Electrolyte

PubMed Central

Gao, Xing; Zu, Lei; Cai, Xiaomin; Li, Ce; Lian, Huiqin; Liu, Yang; Wang, Xiaodong; Cui, Xiuguo

2018-01-01

Insufficient energy density and poor cyclic stability is still challenge for conductive polymer-based supercapacitor. Herein, high performance electrochemical system has been assembled by combining poly (3,4-ethylenedioxythiophene) (PEDOT):poly (styrene sulfonate) (PSS) redox electrode and potassium iodide redox electrolyte, which provide the maximum specific capacity of 51.3 mAh/g and the retention of specific capacity of 87.6% after 3000 cycles due to the synergic effect through a simultaneous redox reaction both in electrode and electrolyte, as well as the catalytic activity for reduction of triiodide of the PEDOT:PSS. PMID:29772662

Hormonal regulation of fluid and electrolyte metabolism during periods of headward fluid shifts

NASA Technical Reports Server (NTRS)

Keil, Lanny C.; Severs, W. B.; Thrasher, T.; Ramsay, D. J.

1991-01-01

In the broadest sense, this project evaluates how spaceflight induced shifts of blood and interstitial fluids into the thorax affect regulation by the central nervous system (CNS) of fluid-electrolyte hormone secretion. Specifically, it focuses on the role of hormones related to salt/water balance and their potential function in the control of intracranial pressure and cerebrospinal fluid (CSF) composition. Fluid-electrolyte status during spaceflight gradually equilibrates, with a reduction in all body fluid compartments. Related to this is the cardiovascular deconditioning of spaceflight which is manifested upon return to earth as orthostatic intolerance.

The Tensile and Shear Bond Strengths of Poly (Methyl Methacrylate) Processed on Electrolytically Etched Ticonium.

DTIC Science & Technology

1986-05-01

METHYL NETHACRYLATE) PROCESSED ON ELECTROLYTICALLY ETCHED TICONIUM A THESIS Presented to the Faculty of The University of Texas Graduate School of...were cast utilizing the manufacturer’s directions for investment, burnout , and casting. Two groups of metal specimens were prepared: 20 for...STRENGTHS OF POLY (METHYL METHACRYLATE) PROCESSED ON ELECTROLYTICALLY ETCHED TICONIUM JOHN EDWARD ZURASKY, M.S. The University of Texas Graduate School

Modeling Insight into Battery Electrolyte Electrochemical Stability and Interfacial Structure.

PubMed

Borodin, Oleg; Ren, Xiaoming; Vatamanu, Jenel; von Wald Cresce, Arthur; Knap, Jaroslaw; Xu, Kang

2017-12-19

Electroactive interfaces distinguish electrochemistry from chemistry and enable electrochemical energy devices like batteries, fuel cells, and electric double layer capacitors. In batteries, electrolytes should be either thermodynamically stable at the electrode interfaces or kinetically stable by forming an electronically insulating but ionically conducting interphase. In addition to a traditional optimization of electrolytes by adding cosolvents and sacrificial additives to preferentially reduce or oxidize at the electrode surfaces, knowledge of the local electrolyte composition and structure within the double layer as a function of voltage constitutes the basis of manipulating an interphase and expanding the operating windows of electrochemical devices. In this work, we focus on how the molecular-scale insight into the solvent and ion partitioning in the electrolyte double layer as a function of applied potential could predict changes in electrolyte stability and its initial oxidation and reduction reactions. In molecular dynamics (MD) simulations, highly concentrated lithium aqueous and nonaqueous electrolytes were found to exclude the solvent molecules from directly interacting with the positive electrode surface, which provides an additional mechanism for extending the electrolyte oxidation stability in addition to the well-established simple elimination of "free" solvent at high salt concentrations. We demonstrate that depending on their chemical structures, the anions could be designed to preferentially adsorb or desorb from the positive electrode with increasing electrode potential. This provides additional leverage to dictate the order of anion oxidation and to effectively select a sacrificial anion for decomposition. The opposite electrosorption behaviors of bis(trifluoromethane)sulfonimide (TFSI) and trifluoromethanesulfonate (OTF) as predicted by MD simulation in highly concentrated aqueous electrolytes were confirmed by surface enhanced infrared spectroscopy. The proton transfer (H-transfer) reactions between solvent molecules on the cathode surface coupled with solvent oxidation were found to be ubiquitous for common Li-ion electrolyte components and dependent on the local molecular environment. Quantum chemistry (QC) calculations on the representative clusters showed that the majority of solvents such as carbonates, phosphates, sulfones, and ethers have significantly lower oxidation potential when oxidation is coupled with H-transfer, while without H-transfer their oxidation potentials reside well beyond battery operating potentials. Thus, screening of the solvent oxidation limits without considering H-transfer reactions is unlikely to be relevant, except for solvents containing unsaturated functionalities (such as C═C) that oxidize without H-transfer. On the anode, the F-transfer reaction and LiF formation during anion and fluorinated solvent reduction could be enhanced or diminished depending on salt and solvent partitioning in the double layer, again giving an additional tool to manipulate the order of reductive decompositions and interphase chemistry. Combined with experimental efforts, modeling results highlight the promise of interphasial compositional control by either bringing the desired components closer to the electrode surface to facilitate redox reaction or expelling them so that they are kinetically shielded from the potential of the electrode.

A bio-inspired molecular water oxidation catalyst for renewable hydrogen generation: an examination of salt effects

NASA Astrophysics Data System (ADS)

Brimblecombe, Robin; Rotstein, Miriam; Koo, Annette; Dismukes, G. Charles; Swiegers, Gerhard F.; Spiccia, Leone

2009-08-01

Most transport fuels are derived from fossil fuels, generate greenhouse gases, and consume significant amounts of water in the extraction, purification, and/or burning processes. The generation of hydrogen using solar energy to split water, ideally from abundant water sources such as sea water or other non-potable sources, could potentially provide an unlimited, clean fuel for the future. Solar, electrochemical water splitting typically combines a photoanode at which water oxidation occurs, with a cathode for proton reduction to hydrogen. In recent work, we have found that a bioinspired tetra-manganese cluster catalyzes water oxidation at relatively low overpotentials (0.38 V) when doped into a Nafion proton conduction membrane deposited on a suitable electrode surface, and illuminated with visible light. We report here that this assembly is active in aqueous and organic electrolyte solutions containing a range of different salts in varying concentrations. Similar photocurrents were obtained using electrolytes containing 0.0 - 0.5 M sodium sulfate, sodium perchlorate or sodium chloride. A slight decline in photocurrent was observed for sodium perchlorate but only at and above 5.0 M concentration. In acetonitrile and acetone solutions containing 10% water, increasing the electrolyte concentration was found to result in leaching of the catalytic species from the membrane and a decrease in photocurrent. Leaching was not observed when the system was tested in an ionic liquid containing water, however, a lower photocurrent was generated than observed in aqueous electrolyte. We conclude that immersion of the membrane in an aqueous solution containing an electrolyte concentration of 0.05 - 0.5M represent good conditions for operation for the cubium/Nafion catalytic system.

Ionic Liquid Hybrid Electrolytes for Lithium-Ion Batteries: A Key Role of the Separator-Electrolyte Interface in Battery Electrochemistry.

PubMed

Huie, Matthew M; DiLeo, Roberta A; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

2015-06-10

Batteries are multicomponent systems where the theoretical voltage and stoichiometric electron transfer are defined by the electrochemically active anode and cathode materials. While the electrolyte may not be considered in stoichiometric electron-transfer calculations, it can be a critical factor determining the deliverable energy content of a battery, depending also on the use conditions. The development of ionic liquid (IL)-based electrolytes has been a research area of recent reports by other researchers, due, in part, to opportunities for an expanded high-voltage operating window and improved safety through the reduction of flammable solvent content. The study reported here encompasses a systematic investigation of the physical properties of IL-based hybrid electrolytes including quantitative characterization of the electrolyte-separator interface via contact-angle measurements. An inverse trend in the conductivity and wetting properties was observed for a series of IL-based electrolyte candidates. Test-cell measurements were undertaken to evaluate the electrolyte performance in the presence of functioning anode and cathode materials, where several promising IL-based hybrid electrolytes with performance comparable to that of conventional carbonate electrolytes were identified. The study revealed that the contact angle influenced the performance more significantly than the conductivity because the cells containing IL-tetrafluoroborate-based electrolytes with higher conductivity but poorer wetting showed significantly decreased performance relative to the cells containing IL-bis(trifluoromethanesulfonyl)imide electrolytes with lower conductivity but improved wetting properties. This work contributes to the development of new IL battery-based electrolyte systems with the potential to improve the deliverable energy content as well as safety of lithium-ion battery systems.

Geometric improvement of electrochemical discharge micro-drilling using an ultrasonic-vibrated electrolyte

NASA Astrophysics Data System (ADS)

Han, Min-Seop; Min, Byung-Kwon; Lee, Sang Jo

2009-06-01

Electrochemical discharge machining (ECDM) is a spark-based micromachining method especially suitable for the fabrication of various microstructures on nonconductive materials, such as glass and some engineering ceramics. However, since the spark discharge frequency is drastically reduced as the machining depth increases ECDM microhole drilling has confronted difficulty in achieving uniform geometry for machined holes. One of the primary reasons for this is the difficulty of sustaining an adequate electrolyte flow in the narrow gap between the tool and the workpiece, which results in a widened taper at the hole entrance, as well as a significant reduction of the machining depth. In this paper, ultrasonic electrolyte vibration was used to enhance the machining depth of the ECDM drilling process by assuring an adequate electrolyte flow, thus helping to maintain consistent spark generation. Moreover, the stability of the gas film formation, as well as the surface quality of the hole entrance, was improved with the aid of a side-insulated electrode and a pulse-power generator. The side-insulated electrode prevented stray electrolysis and concentrated the spark discharge at the tool tip, while the pulse voltage reduced thermal damage to the workpiece surface by introducing a periodic pulse-off time. Microholes were fabricated in order to investigate the effects of ultrasonic assistance on the overcut and machining depth of the holes. The experimental results demonstrated that the possibility of consistent spark generation and the machinability of microholes were simultaneously enhanced.

Nonconsumable electrode assembly and use thereof for the electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Ray, Siba P.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor attached to a ceramic electrode body by a metal bond on a portion of the body having a level of free metal or metal alloy sufficient to effect a metal bond.

A stable perovskite electrolyte in moist air for Li-ion batteries.

PubMed

Li, Yutao; Xu, Henghui; Chien, Po-Hsiu; Wu, Nan; Xin, Sen; Xue, Leigang; Park, Kyusung; Hu, Yan-Yan; Goodenough, John B

2018-05-07

Solid-oxide Li+ electrolytes of a rechargeable cell are generally sensitive to moisture in the air, H+ exchanges for the mobile Li+ of the electrolyte and forms insulating surface phases at the electrolyte interfaces and in the grain boundaries of a polycrystalline membrane. These surface phases dominate the total interfacial resistance of a conventional rechargeable cell having a solid-electrolyte separator. We report a new perovskite Li+ solid electrolyte, Li0.38Sr0.44Ta0.7Hf0.3O2.95F0.05, having a Li-ion conductivity σLi = 4.8×10-4 S cm-1 at 25 oC that does not react with water having 3≤pH≤14. The solid electrolyte with a thin Li+-conducting polymer on its surface to prevent reduction of Ta5+ is wet by metallic lithium and provides low-impedance dendrite-free plating/stripping of a lithium anode. It is also stable on contact with a composite polymer cathode. With this solid electrolyte, we demonstrate excellent cycling performance of an all-solid-state Li/LiFePO4 cell, a Li-S cell with a polymer-gel cathode, and a supercapacitor. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanistic Study of Electrolyte Additives to Stabilize High-Voltage Cathode–Electrolyte Interface in Lithium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Han; Maglia, Filippo; Lamp, Peter

Current developments of electrolyte additives to stabilize electrode-electrolyte interface in Li-ion batteries highly rely on a trial-and-error search, which involves repetitive testing and intensive amount of resources. The lack of understandings on the fundamental protection mechanisms of the additives significantly increases the difficulty for the transformational development of new additives. In this study, we investigated two types of individual protection routes to build a robust cathode-electrolyte interphase at high potentials: (i) a direct reduction in the catalytic decomposition of the electrolyte solvent; and (ii) formation of a “corrosion inhibitor film” that prevents severely attack and passivation from protons that generatedmore » from the solvent oxidation, even the decomposition of solvent cannot not mitigated. Effect of three exemplary electrolyte additives: (i) lithium difluoro(oxalato)borate (LiDFOB); (ii) 3-hexylthiophene (3HT); and (iii) tris(hexafluoro-iso-propyl)phosphate (HFiP), on LiNi0.6Mn0.2Co0.2O2 (NMC 622) cathode were investigated to validate our hypothesis. It is demonstrated that understandings of both electrolyte additives and solvent are essential and careful balance between the cathode protection mechanism of additives and their side effects is critical to obtain optimum results. More importantly, this study opens up new directions of rational design of functional electrolyte additives for the next generation high-energy density lithium-ion chemistries.« less

Ionic Liquid Catalyzed Electrolyte for Electrochemical Polyaniline Supercapacitors

NASA Astrophysics Data System (ADS)

Inamdar, A. I.; Im, Hyunsik; Jung, Woong; Kim, Hyungsang; Kim, Byungchul; Yu, Kook-Hyun; Kim, Jin-Sang; Hwang, Sung-Min

2013-05-01

The effect of different wt.% of ionic liquid "1,6-bis (trimethylammonium-1-yl) hexane tetrafluoroborate" in 0.5 M LiClO4+PC electrolyte on the supercapacitor properties of polyaniline (PANI) thin film are investigated. The PANI film is synthesized using electropolymerization of aniline in the presence of sulfuric acid. The electrochemical properties of the PANI thin film are studied by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements. The optimum amount of the ionic liquid is found to be 2 wt.% which provides better ionic conductivity of the electrolyte. The highest specific capacitance of 259 F/g is obtained using the 2 wt.% electrolyte. This capacitance remains at up to 208 F/g (80% capacity retention) after 1000 charge-discharge cycles at a current density of 0.5 mA/g. The PANI film in the 2 wt.% ionic liquid catalyzed 0.5 M LiClO4+PC electrolyte shows small electrochemical resistance, better rate performance and higher cyclability. The increased ionic conductivity of the 2 wt.% ionic liquid catalyzed electrolyte causes a reduction in resistance at the electrode/electrolyte interface, which can be useful in electrochemically-preferred power devices for better applicability.

Cascade redox flow battery systems

DOEpatents

Horne, Craig R.; Kinoshita, Kim; Hickey, Darren B.; Sha, Jay E.; Bose, Deepak

2014-07-22

A reduction/oxidation ("redox") flow battery system includes a series of electrochemical cells arranged in a cascade, whereby liquid electrolyte reacts in a first electrochemical cell (or group of cells) before being directed into a second cell (or group of cells) where it reacts before being directed to subsequent cells. The cascade includes 2 to n stages, each stage having one or more electrochemical cells. During a charge reaction, electrolyte entering a first stage will have a lower state-of-charge than electrolyte entering the nth stage. In some embodiments, cell components and/or characteristics may be configured based on a state-of-charge of electrolytes expected at each cascade stage. Such engineered cascades provide redox flow battery systems with higher energy efficiency over a broader range of current density than prior art arrangements.

Effects of surface chemistry and microstructure of electrolyte on oxygen reduction kinetics of solid oxide fuel cells

DOE PAGES

Park, Joong Sun; An, Jihwan; Lee, Min Hwan; ...

2015-11-01

In this study, we report systematic investigation of the surface properties of yttria-stabilized zirconia (YSZ) electrolytes with the control of the grain boundary (GB) density at the surface, and its effects on electrochemical activities. The GB density of thin surface layers deposited on single crystal YSZ substrates is controlled by changing the annealing temperature (750-1450 °C). Higher oxygen reduction reactions (ORR) kinetics is observed in samples annealed at lower temperatures. The higher ORR activity is ascribed to the higher GB density at the YSZ surface where 'mobile' oxide ion vacancies are more populated. Meanwhile, oxide ion vacancies concurrently created withmore » yttrium segregation at the surface at the higher annealing temperature are considered inactive to oxygen incorporation reactions. Our results provide additional insight into the interplay between the surface chemistry, microstructures, and electrochemical activity. They potentially provide important guidelines for engineering the electrolyte electrode interfaces of solid oxide fuel cells for higher electrochemical performance.« less

The healing effect of electrolytic-reduction ion water on burn wounds.

PubMed

Okajima, Masahiro; Shimokawa, Ken-ichi; Ishii, Fumiyoshi

2010-02-01

We prepared a lotion using electrolytic-reduction ion water (ERI), and evaluated the healing effects of this lotion (ERI lotion) on burn wounds. Third degree burn wounds were induced in the mouse dorsal skin, and ERI lotion or physiological salt (PS) lotion was applied to the wounds from immediately after injury [ERI (+) group and ERI (-) group as a control group, respectively]. The burn wound area was measured, and its serial changes were evaluated. In addition, histological examination of the burn wound site (on day 3) was performed. Comparison of the ERI (+) and (-) groups showed a significant reduction in the burn wound area in the former. Histological examination confirmed many interstitial spaces, blood vessels, and lymphatic vessels in the subcutaneous tissue in the ERI (-) compared with the ERI (+) group. These results suggest the promotion of burn wound healing by ERI lotion.

Plasma Electrolytic Oxidation Coatings on Pure Ti Substrate: Effects of Na3PO4 Concentration on Morphology and Corrosion Behavior of Coatings in Ringer's Physiological Solution

NASA Astrophysics Data System (ADS)

Roknian, Masoud; Fattah-alhosseini, Arash; Gashti, Seyed Omid

2018-03-01

Plasma electrolytic oxidation has been used as a relatively new method for applying ceramic coatings having different features. In the present study, commercially pure titanium is used as substrate, and effects of trisodium phosphate electrolyte concentration on the microstructure, as well as corrosion behavior of the coating in Ringer's physiological solution are investigated. The morphology and phase compositions of coatings were analyzed by using scanning electron microscopy (SEM) and x-ray diffraction patterns. The study on the corrosion behavior of samples in a Ringer's physiological solution was carried out using open-circuit potential potentiodynamic polarization and electrochemical impedance spectroscopy. The results of electrochemical analysis proved that higher concentration of phosphate electrolyte leads to increase in the corrosion resistance of applied coatings. Accordingly, obtained results revealed that the optimum electrolyte concentration for the best corrosion behavior was 20 g L-1. Furthermore, SEM images and reduction in the dielectric breakdown potential indicated that increase in the electrolyte concentration leads to morphological improvement and smoothening of the surface.

Electrochemical Preparation of Polyaniline Nanowires with the Used Electrolyte Solution Treated with the Extraction Process and Their Electrochemical Performance.

PubMed

Wu, Ying; Wang, Jixiao; Ou, Bin; Zhao, Song; Wang, Zhi; Wang, Shichang

2018-02-12

Electrochemical polymerization of aniline is one of the most promising methods to prepare polyaniline (PANI) materials. However, during this process, the electrolyte solution must be replaced after electropolymerization of a certain time because of the generation and the accumulation of the by-products, which have significant effects on the morphology, purity and properties of PANI products. Treatment and recycling of the used electrolyte solution are worthwhile to study to reduce the high treatment cost of the used electrolyte solution containing aniline and its polymerization by-products. Here, the composition of the used electrolyte solution was separated and determined by high performance liquid chromatography coupled with diode array detection (HPLC-DAD) in the range of ultraviolet and visible (UV-Vis) light. The analysis results revealed that the used electrolyte solution consisted of aniline, p-hydroquinone (HQ), p-benzoquinone (BQ), co-oligomers of aniline and p-benzoquinone (CAB) and acid. Then, n-octanol and 2-octanone were selected as extracts to remove HQ, BQ and CAB from the used electrolyte solution. Following that, the recycled electrolyte solution was prepared by adjusting the concentration of aniline and acid of the aqueous phase, and the electrochemical polymerization process was conducted. Finally, the obtained PANI was characterized by scanning electron microscope (SEM) and electrochemical methods. The experimental results clearly demonstrate that the morphology and specific capacitance of PANI produced from the recycled electrolyte solution can be recovered completely. This research paves the way for reusing the used electrolyte solution for aniline electrochemical polymerization.

Electrochemical Preparation of Polyaniline Nanowires with the Used Electrolyte Solution Treated with the Extraction Process and Their Electrochemical Performance

PubMed Central

Wu, Ying; Wang, Jixiao; Ou, Bin; Zhao, Song; Wang, Zhi; Wang, Shichang

2018-01-01

Electrochemical polymerization of aniline is one of the most promising methods to prepare polyaniline (PANI) materials. However, during this process, the electrolyte solution must be replaced after electropolymerization of a certain time because of the generation and the accumulation of the by-products, which have significant effects on the morphology, purity and properties of PANI products. Treatment and recycling of the used electrolyte solution are worthwhile to study to reduce the high treatment cost of the used electrolyte solution containing aniline and its polymerization by-products. Here, the composition of the used electrolyte solution was separated and determined by high performance liquid chromatography coupled with diode array detection (HPLC-DAD) in the range of ultraviolet and visible (UV-Vis) light. The analysis results revealed that the used electrolyte solution consisted of aniline, p-hydroquinone (HQ), p-benzoquinone (BQ), co-oligomers of aniline and p-benzoquinone (CAB) and acid. Then, n-octanol and 2-octanone were selected as extracts to remove HQ, BQ and CAB from the used electrolyte solution. Following that, the recycled electrolyte solution was prepared by adjusting the concentration of aniline and acid of the aqueous phase, and the electrochemical polymerization process was conducted. Finally, the obtained PANI was characterized by scanning electron microscope (SEM) and electrochemical methods. The experimental results clearly demonstrate that the morphology and specific capacitance of PANI produced from the recycled electrolyte solution can be recovered completely. This research paves the way for reusing the used electrolyte solution for aniline electrochemical polymerization. PMID:29439514

Process for producing elements from a fused bath using a metal strap and ceramic electrode body nonconsumable electrode assembly

DOEpatents

Byrne, S.C.

1984-07-03

A nonconsumable electrode assembly is described suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a ceramic electrode body and a metal subassembly of a metal conductor rod and at least one metal strap affixed to an end of the rod with opposing portions extending radially outwardly from the rod axis and having the ends of the strap attached to the electrode body. 7 figs.

Electrochemical reduction of toluene to methylcyclohexane for use as an energy carrier

NASA Astrophysics Data System (ADS)

Matsuoka, Koji; Miyoshi, Kota; Sato, Yasushi

2017-03-01

The electrochemical reduction of liquid toluene to methylcyclohexane (MCH) was investigated using a membrane electrode assembly (MEA) and high active-area catalysts commonly used in proton exchange membrane fuel cells (PEMFC). The current density on Pt/C was higher than on PtRu/C, which was comparable to that of alkaline water electrolysis. The potential of hydrogen evolution was shifted negatively by the presence of toluene and MCH. Therefore, the toluene reduction reaction was almost perfectly separated from the hydrogen evolution reaction. Toluene was perfectly reduced to MCH at around 0 V vs. RHE on PtRu/C and no by-products were detected in the solutions after electrolysis. MCH was produced at a Faradaic efficiency of more than 96% by carefully keeping the potential above -30 mV vs. RHE. Through this electrolytic process, we were able to reduce the concentration of toluene from 100% to 7.6%.

Electrodeposition of magnesium and magnesium/aluminum alloys

DOEpatents

Mayer, Anton

1988-01-01

Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

Electrowinning process with electrode compartment to avoid contamination of electrolyte

DOEpatents

Poa, Davis S.; Pierce, R. Dean; Mulcahey, Thomas P.; Johnson, Gerald K.

1993-01-01

An electrolytic process and apparatus for reducing calcium oxide in a molten electrolyte of CaCl.sub.2 -CaF.sub.2 with a graphite anode in which particles or other contamination from the anode is restricted by the use of a porous barrier in the form of a basket surrounding the anode which may be removed from the electrolyte to burn the graphite particles, and wherein the calcium oxide feed is introduced to the anode compartment to increase the oxygen ion concentration at the anode.

Electrodeposition of magnesium and magnesium/aluminum alloys

DOEpatents

Mayer, A.

1988-01-21

Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

Potable water recovery for spacecraft application by electrolytic pretreatment/air evaporation

NASA Technical Reports Server (NTRS)

Wells, G. W.

1975-01-01

A process for the recovery of potable water from urine using electrolytic pretreatment followed by distillation in a closed-cycle air evaporator has been developed and tested. Both the electrolytic pretreatment unit and the air evaporation unit are six-person, flight-concept prototype, automated units. Significantly extended wick lifetimes have been achieved in the air evaporation unit using electrolytically pretreated, as opposed to chemically pretreated, urine feed. Parametric test data are presented on product water quality, wick life, process power, maintenance requirements, and expendable requirements.

Fundamental Investigations of Durability at a Polymer Electrolyte-Electrode Interface

DTIC Science & Technology

2008-04-01

before before σ -σ σ after before before σ -σ σ Cleavage of the side chain ether linkage (Fig. 3), which intrudes into the hydrophilic ionic cluster...directly correlated to peroxide yields measured Figure 3: ATR-FTIR Spectrum of Nafion ®112 (H-form) indicating absorption bands obtained using...electrocatalyst-based fuel cell electrode (referred as sacrificial electrode) directly into the liquid electrolyte, in which oxygen reduction was

Pulsating electrolyte flow in a full vanadium redox battery

NASA Astrophysics Data System (ADS)

Ling, C. Y.; Cao, H.; Chng, M. L.; Han, M.; Birgersson, E.

2015-10-01

Proper management of electrolyte flow in a vanadium redox battery (VRB) is crucial to achieve high overall system efficiency. On one hand, constant flow reduces concentration polarization and by extension, energy efficiency; on the other hand, it results in higher auxiliary pumping costs, which can consume around 10% of the discharge power. This work seeks to reduce the pumping cost by adopting a novel pulsing electrolyte flow strategy while retaining high energy efficiency. The results indicate that adopting a short flow period, followed by a long flow termination period, results in high energy efficiencies of 80.5% with a pumping cost reduction of over 50%.

Determination of the Cryolite Ratio of KF-NaF-AlF3 Electrolyte by Conductivity Method

NASA Astrophysics Data System (ADS)

Yan, Hengwei; Yang, Jianhong; Liu, Zhanwei; Wang, Chengzhi; Ma, Wenhui

2018-05-01

The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF3 system acid (CR < 3) electrolyte by means of electrical conductivity was initially developed, and the formula for calculating the CR was deduced. This method has the advantages of simple operation and high precision. In addition, the relative standard deviations (RSD) of the measurement are < 1.2 pct, and the analysis error of the NaF or KF content has little effect on the determination of the CR.

Neurologic manifestations of electrolyte disturbances.

PubMed

Riggs, Jack E

2002-02-01

Electrolyte disturbances occur commonly and are associated with a variety of characteristic neurologic manifestations involving both the central and peripheral nervous systems. Electrolyte disturbances are essentially always secondary processes. Effective management requires identification and treatment of the underlying primary disorder. Since neurological symptoms of electrolyte disorders are generally functional rather than structural, the neurologic manifestations of electrolyte disturbances are typically reversible. The neurologic manifestations of serum sodium, potassium, calcium, and magnesium disturbances are reviewed.

Bioelectrochemically-assisted reductive dechlorination of 1,2-dichloroethane by a Dehalococcoides-enriched microbial culture.

PubMed

Leitão, Patrícia; Rossetti, Simona; Nouws, Henri P A; Danko, Anthony S; Majone, Mauro; Aulenta, Federico

2015-11-01

The aim of this study was to verify the possibility to use a polarized graphite electrode as an electron donor for the reductive dechlorination of 1,2-dichloroethane, an ubiquitous groundwater contaminant. The rate of 1,2-DCA dechlorination almost linearly increased by decreasing the set cathode potential over a broad range of set cathode potentials (i.e., from -300 mV to -900 mV vs. the standard hydrogen electrode). This process was primarily dependent on electrolytic H2 generation. On the other hand, reductive dechlorination proceeded (although quite slowly) with a very high Coulombic efficiency (near 70%) at a set cathode potential of -300 mV, where no H2 production occurred. Under this condition, reductive dechlorination was likely driven by direct electron uptake from the surface of the polarized electrode. Taken as a whole, this study further extends the range of chlorinated contaminants which can be treated with bioelectrochemical systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Amorphous nickel boride membrane on a platinum-nickel alloy surface for enhanced oxygen reduction reaction.

PubMed

He, Daping; Zhang, Libo; He, Dongsheng; Zhou, Gang; Lin, Yue; Deng, Zhaoxiang; Hong, Xun; Wu, Yuen; Chen, Chen; Li, Yadong

2016-08-09

The low activity of the oxygen reduction reaction in polymer electrolyte membrane fuel cells is a major barrier for electrocatalysis, and hence needs to be optimized. Tuning the surface electronic structure of platinum-based bimetallic alloys, a promising oxygen reduction reaction catalyst, plays a key role in controlling its interaction with reactants, and thus affects the efficiency. Here we report that a dealloying process can be utilized to experimentally fabricate the interface between dealloyed platinum-nickel alloy and amorphous nickel boride membrane. The coating membrane works as an electron acceptor to tune the surface electronic structure of the platinum-nickel catalyst, and this composite catalyst composed of crystalline platinum-nickel covered by amorphous nickel boride achieves a 27-times enhancement in mass activity relative to commercial platinum/carbon at 0.9 V for the oxygen reduction reaction performance. Moreover, this interactional effect between a crystalline surface and amorphous membrane can be readily generalized to facilitate the 3-times higher catalytic activity of commercial platinum/carbon.

Photochemical reduction of cytochrome c by a 1,4,5,8-naphthalenediimide radical anion.

PubMed

Campos, Ivana B; Nantes, Iseli L; Politi, Mario J; Brochsztain, Sergio

2004-01-01

Steady-state UV irradiation of aqueous solutions containing cytochrome c (cyt c) and N,N'-bis(2-phosphonoethyl)-1,4,5,8-naphthalenediimide (BPNDI), a water-soluble aromatic imide, resulted in the reduction of the heme iron from the Fe(III) to the Fe(II) oxidation state. The reaction kinetics were followed by the increase of the ferrocytochrome c absorbance band at 549 nm. The rate of the photochemical reaction was pH dependent, reaching its maximum values over the pH range 4-7. Addition of electrolyte (NaCl) at pH 5 resulted in a decrease in the reaction rate, as expected for reactions between oppositely charged species. Flash photolysis studies revealed that the actual reductant in the reaction was a photogenerated BPNDI radical anion, which transferred an electron to the cyt c heme iron. The participation of imide radicals in the process was confirmed by the ready reduction of cyt c by BPNDI radicals chemically generated with sodium dithionite.

Process to remove rare earth from IFR electrolyte

DOEpatents

Ackerman, John P.; Johnson, Terry R.

1994-01-01

The invention is a process for the removal of rare earths from molten chloride electrolyte salts used in the reprocessing of integrated fast reactor fuel (IFR). The process can be used either continuously during normal operation of the electrorefiner or as a batch process. The process consists of first separating the actinide values from the salt before purification by removal of the rare earths. After replacement of the actinides removed in the first step, the now-purified salt electrolyte has the same uranium and plutonium concentration and ratio as when the salt was removed from the electrorefiner.

Process to remove rare earth from IFR electrolyte

DOEpatents

Ackerman, J.P.; Johnson, T.R.

1992-01-01

The invention is a process for the removal of rare earths from molten chloride electrolyte salts used in the reprocessing of integrated fast reactor fuel (IFR). The process can be used either continuously during normal operation of the electrorefiner or as a batch process. The process consists of first separating the actinide values from the salt before purification by removal of the rare earths. After replacement of the actinides removed in the first step, the now-purified salt electrolyte has the same uranium and plutonium concentration and ratio as when the salt was removed from the electrorefiner.

Process to remove rare earth from IFR electrolyte

DOEpatents

Ackerman, J.P.; Johnson, T.R.

1994-08-09

The invention is a process for the removal of rare earths from molten chloride electrolyte salts used in the reprocessing of integrated fast reactor fuel (IFR). The process can be used either continuously during normal operation of the electrorefiner or as a batch process. The process consists of first separating the actinide values from the salt before purification by removal of the rare earths. After replacement of the actinides removed in the first step, the now-purified salt electrolyte has the same uranium and plutonium concentration and ratio as when the salt was removed from the electrorefiner. 1 fig.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, Mark W.; George, William A.

1991-01-01

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, Mark W.; George, William A.

1988-01-01

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, Mark W.; George, William A.

1989-01-01

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates.

PubMed

Chadderdon, Xiaotong H; Chadderdon, David J; Matthiesen, John E; Qiu, Yang; Carraher, Jack M; Tessonnier, Jean-Philippe; Li, Wenzhen

2017-10-11

Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. However, understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. In this work, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. Understanding the underlying mechanisms enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.

Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chadderdon, Xiaotong H.; Chadderdon, David J.; Matthiesen, John E.

Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. Understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. Here, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions ofmore » each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. By understanding the underlying mechanisms it enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.« less

Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates

DOE PAGES

Chadderdon, Xiaotong H.; Chadderdon, David J.; Matthiesen, John E.; ...

2017-09-13

Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. Understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. Here, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions ofmore » each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. By understanding the underlying mechanisms it enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.« less

Controlling Solid-Electrolyte-Interphase Layer by Coating P-Type Semiconductor NiOx on Li4Ti5O12 for High-Energy-Density Lithium-Ion Batteries.

PubMed

Jo, Mi Ru; Lee, Gi-Hyeok; Kang, Yong-Mook

2015-12-23

Li4Ti5O12 is a promising anode material for rechargeable lithium batteries due to its well-known zero strain and superb kinetic properties. However, Li4Ti5O12 shows low energy density above 1 V vs Li(+)/Li. In order to improve the energy density of Li4Ti5O12, its low-voltage intercalation behavior beyond Li7Ti5O12 has been demonstrated. In this approach, the extended voltage window is accompanied by the decomposition of liquid electrolyte below 1 V, which would lead to an excessive formation of solid electrolyte interphase (SEI) films. We demonstrate an effective method to improve electrochemical performance of Li4Ti5O12 in a wide working voltage range by coating Li4Ti5O12 powder with p-type semiconductor NiOx. Ex situ XRD, XPS, and FTIR results show that the NiOx coating suppresses electrochemical reduction reactions of the organic SEI components to Li2CO3, thereby promoting reversibility of the charge/discharge process. The NiOx coating layer offers a stable SEI film for enhanced rate capability and cyclability.

Interfacial Redox Reactions Associated Ionic Transport in Oxide-Based Memories.

PubMed

Younis, Adnan; Chu, Dewei; Shah, Abdul Hadi; Du, Haiwei; Li, Sean

2017-01-18

As an alternative to transistor-based flash memories, redox reactions mediated resistive switches are considered as the most promising next-generation nonvolatile memories that combine the advantages of a simple metal/solid electrolyte (insulator)/metal structure, high scalability, low power consumption, and fast processing. For cation-based memories, the unavailability of in-built mobile cations in many solid electrolytes/insulators (e.g., Ta 2 O 5 , SiO 2 , etc.) instigates the essential role of absorbed water in films to keep electroneutrality for redox reactions at counter electrodes. Herein, we demonstrate electrochemical characteristics (oxidation/reduction reactions) of active electrodes (Ag and Cu) at the electrode/electrolyte interface and their subsequent ions transportation in Fe 3 O 4 film by means of cyclic voltammetry measurements. By posing positive potentials on Ag/Cu active electrodes, Ag preferentially oxidized to Ag + , while Cu prefers to oxidize into Cu 2+ first, followed by Cu/Cu + oxidation. By sweeping the reverse potential, the oxidized ions can be subsequently reduced at the counter electrode. The results presented here provide a detailed understanding of the resistive switching phenomenon in Fe 3 O 4 -based memory cells. The results were further discussed on the basis of electrochemically assisted cations diffusions in the presence of absorbed surface water molecules in the film.

Stable dye-sensitized solar cells based on a gel electrolyte with ethyl cellulose as the gelator

NASA Astrophysics Data System (ADS)

Vasei, Maryam; Tajabadi, Fariba; Jabbari, Ali; Taghavinia, Nima

2015-09-01

A simple gelating process is developed for the conventional acetonitrile-based electrolyte of dye solar cells, based on ethyl cellulose as the gelator. The electrolyte becomes quasi-solid-state upon addition of an ethanolic solution of ethyl cellulose to the conventional acetonitrile-based liquid electrolyte. The photovoltaic conversion efficiency with the new gel electrolyte is only slightly lower than with the liquid electrolyte, e.g., 6.5 % for liquid electrolyte versus 5.9 % for gel electrolyte with 5.8 wt% added ethyl cellulose. Electrolyte gelation has small effect on the ionic diffusion coefficient of iodide, and the devices are remarkably stable for at least 550 h under irradiation at 55 °C.

Cycling performance of lithium metal polymer cells assembled with ionic liquid and poly(3-methyl thiophene)/carbon nanotube composite cathode

NASA Astrophysics Data System (ADS)

Kim, Dong-Won; Sivakkumar, S. R.; MacFarlane, Douglas R.; Forsyth, Maria; Sun, Yang-Kook

A poly(3-methylthiophene) (PMT)/multi-walled carbon nanotube (CNT) composite is synthesized by in situ chemical polymerization. The PMT/CNT composite is used as an active cathode material in lithium metal polymer cells assembled with ionic liquid (IL) electrolytes. The IL electrolyte consists of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF 4) and LiBF 4. A small amount of vinylene carbonate is added to the IL electrolyte to prevent the reductive decomposition of the imidazolium cation in EMIBF 4. A porous poly(vinylidene fluoride- co-hexafluoropropylene) (P(VdF- co-HFP)) film is used as a polymer membrane for assembling the cells. Electrochemical properties of the PMT/CNT composite electrode in the IL electrolyte are evaluated and the effect of vinylene carbonate on the cycling performance of the lithium metal polymer cells is investigated. The cells assembled with a non-flammable IL electrolyte and a PMT/CNT composite cathode are promising candidates for high-voltage-power sources with enhanced safety.

Effect of Concentration on the Electrochemistry and Speciation of the Magnesium Aluminum Chloride Complex Electrolyte Solution.

PubMed

See, Kimberly A; Liu, Yao-Min; Ha, Yeyoung; Barile, Christopher J; Gewirth, Andrew A

2017-10-18

Magnesium batteries offer an opportunity to use naturally abundant Mg and achieve large volumetric capacities reaching over four times that of conventional Li-based intercalation anodes. High volumetric capacity is enabled by the use of a Mg metal anode in which charge is stored via electrodeposition and stripping processes, however, electrolytes that support efficient Mg electrodeposition and stripping are few and are often prepared from highly reactive compounds. One interesting electrolyte solution that supports Mg deposition and stripping without the use of highly reactive reagents is the magnesium aluminum chloride complex (MACC) electrolyte. The MACC exhibits high Coulombic efficiencies and low deposition overpotentials following an electrolytic conditioning protocol that stabilizes species necessary for such behavior. Here, we discuss the effect of the MgCl 2 and AlCl 3 concentrations on the deposition overpotential, current density, and the conditioning process. Higher concentrations of MACC exhibit enhanced Mg electrodeposition current density and much faster conditioning. An increase in the salt concentrations causes a shift in the complex equilibria involving both cations. The conditioning process is strongly dependent on the concentration suggesting that the electrolyte is activated through a change in speciation of electrolyte complexes and is not simply due to the annihilation of electrolyte impurities. Additionally, the presence of the [Mg 2 (μ-Cl) 3 ·6THF] + in the electrolyte solution is again confirmed through careful analysis of experimental Raman spectra coupled with simulation and direct observation of the complex in sonic spray ionization mass spectrometry. Importantly, we suggest that the ∼210 cm -1 mode commonly observed in the Raman spectra of many Mg electrolytes is indicative of the C 3v symmetric [Mg 2 (μ-Cl) 3 ·6THF] + . The 210 cm -1 mode is present in many electrolytes containing MgCl 2 , so its assignment is of broad interest to the Mg electrolyte community.

Solid oxide fuel cells with bi-layered electrolyte structure

NASA Astrophysics Data System (ADS)

Zhang, Xinge; Robertson, Mark; Decès-Petit, Cyrille; Xie, Yongsong; Hui, Rob; Qu, Wei; Kesler, Olivera; Maric, Radenka; Ghosh, Dave

In this work, we have developed solid oxide fuel cells with a bi-layered electrolyte of 2 μm SSZ and 4 μm SDC using tape casting, screen printing, and co-firing processes. The cell reached power densities of 0.54 W cm -2 at 650 °C and 0.85 W cm -2 at 700 °C, with open circuit voltage (OCV) values larger than 1.02 V. The electrical leaking between anode and cathode through an SDC electrolyte has been blocked in the bi-layered electrolyte structure. However, both the electrolyte resistance (R el) and electrode polarization resistance (R p,a+c) increased in comparison to cells with single-layered SDC electrolytes. The formation of a solid solution of (Ce, Zr)O 2- x during sintering process and the flaws in the bi-layered electrolyte structure seem to be the main causes for the increase in the R el value (0.32 Ω cm 2) at 650 °C, which is almost one order of magnitude higher than the calculated value.

Electrolytic recovery of reactor metal fuel

DOEpatents

Miller, W.E.; Tomczuk, Z.

1994-09-20

A new electrolytic process and apparatus are provided using sodium, cerium or a similar metal in alloy or within a sodium beta or beta[double prime]-alumina sodium ion conductor to electrolytically displace each of the spent fuel metals except for cesium and strontium on a selective basis from the electrolyte to an inert metal cathode. Each of the metals can be deposited separately. An electrolytic transfer of spent fuel into the electrolyte includes a sodium or cerium salt in the electrolyte with sodium or cerium alloy being deposited on the cathode during the transfer of the metals from the spent fuel. The cathode with the deposit of sodium or cerium alloy is then shunted to an anode and the reverse transfer is carried out on a selective basis with each metal being deposited separately at the cathode. The result is that the sodium or cerium needed for the process is regenerated in the first step and no additional source of these reactants is required. 2 figs.

Electrolytic recovery of reactor metal fuel

DOEpatents

Miller, W.E.; Tomczuk, Z.

1993-02-03

This invention is comprised of a new electrolytic process and apparatus using sodium, cerium or a similar metal in an alloy or within a sodium beta or beta-alumina sodium ion conductor to electrolytically displace each of the spent fuel metals except for Cesium and strontium on a selective basis from the electrolyte to an inert metal cathode. Each of the metals can be deposited separately. An electrolytic transfer of spent fuel into the electrolyte includes a sodium or cerium salt in the electrolyte with sodium or cerium alloy being deposited on the cathode during the transfer of the metals from the spent fuel. The cathode with the deposit of sodium or cerium alloy is then changed to an anode and the reverse transfer is carried out on a selective basis with each metal being deposited separately at the cathode. The result is that the sodium or cerium needed for the process is regenerated in the first step and no additional source of these reactants is required.

Electrolytic recovery of reactor metal fuel

DOEpatents

Miller, William E.; Tomczuk, Zygmunt

1994-01-01

A new electrolytic process and apparatus are provided using sodium, cerium or a similar metal in alloy or within a sodium beta or beta"-alumina sodium ion conductor to electrolytically displace each of the spent fuel metals except for cesium and strontium on a selective basis from the electrolyte to an inert metal cathode. Each of the metals can be deposited separately. An electrolytic transfer of spent fuel into the electrolyte includes a sodium or cerium salt in the electrolyte with sodium or cerium alloy being deposited on the cathode during the transfer of the metals from the spent fuel. The cathode with the deposit of sodium or cerium alloy is then chanted to an anode and the reverse transfer is carried out on a selective basis with each metal being deposited separately at the cathode. The result is that the sodium or cerium needed for the process is regenerated in the first step and no additional source of these reactants is required.

Electrochemical generation of useful chemical species from lunar materials

NASA Technical Reports Server (NTRS)

Sammells, Anthony F.; Semkow, Krystyna W.

1987-01-01

A high temperature electrolytic cell which simultaneously generates oxygen at the anode and liquid alkali metals at the cathode is electrochemically characterized. The electrolytic technology being investigated utilizes the oxygen vacancy conducting solid electrolyte, yttria stabilized zirconia, which effectively separates the oxygen evolving (at La0.89Sr0.10MnO3) and alkali metal (Li, Na) reducing (from a molten salt at either Pt or FeSi2) half cell reactions. In the finally engineered cell liquid alkali metal would be continuously removed from the cathode compartment and used as an effective reductant for the direct thermochemical refining of lunar ores to their metallic state with simultaneous oxidation of the alkali metal to its oxide. The alkali metal oxide would then be reintroduced into the electrolytic cell to complete the overall system cycle.

Electrochemical generation of useful chemical species from lunar materials

NASA Astrophysics Data System (ADS)

Sammells, Anthony F.; Semkow, Krystyna W.

1987-09-01

A high temperature electrolytic cell which simultaneously generates oxygen at the anode and liquid alkali metals at the cathode is electrochemically characterized. The electrolytic technology being investigated utilizes the oxygen vacancy conducting solid electrolyte, yttria stabilized zirconia, which effectively separates the oxygen evolving (at La0.89Sr0.10MnO3) and alkali metal (Li, Na) reducing (from a molten salt at either Pt or FeSi2) half cell reactions. In the finally engineered cell liquid alkali metal would be continuously removed from the cathode compartment and used as an effective reductant for the direct thermochemical refining of lunar ores to their metallic state with simultaneous oxidation of the alkali metal to its oxide. The alkali metal oxide would then be reintroduced into the electrolytic cell to complete the overall system cycle.

Reduction of capacity decay in vanadium flow batteries by an electrolyte-reflow method

NASA Astrophysics Data System (ADS)

Wang, Ke; Liu, Le; Xi, Jingyu; Wu, Zenghua; Qiu, Xinping

2017-01-01

Electrolyte imbalance is a major issue with Vanadium flow batteries (VFBs) as it has a significant impact on electrolyte utilization and cycle life over extended charge-discharge cycling. This work seeks to reduce capacity decay and prolong cycle life of VFBs by adopting a novel electrolyte-reflow method. Different current density and various start-up time of the method are investigated in the charge-discharge tests. The results show that the capacity decay rate is reduced markedly and the cycle life is prolonged substantially by this method. In addition, the coulomb efficiency, voltage efficiency and energy efficiency remain stable during the whole cycle life test, which indicates this method has little impact on the long lifetime performance of the VFBs. The method is low-cost, simple, effective, and can be applied in industrial VFB productions.

Electrolytic trapping of iodine from process gas streams

DOEpatents

Horner, Donald E.; Mailen, James C.; Posey, Franz A.

1977-01-25

A method for removing molecular, inorganic, and organic forms of iodine from process gas streams comprises the electrolytic oxidation of iodine in the presence of cobalt-III ions. The gas stream is passed through the anode compartment of a partitioned electrolytic cell having a nitric acid anolyte containing a catalytic amount of cobalt to cause the oxidation of effluent iodine species to aqueous soluble species.

High capacity of lithium-sulfur batteries at low electrolyte/sulfur ratio enabled by an organosulfide containing electrolyte

DOE PAGES

Chen, Shuru; Gao, Yue; Yu, Zhaoxin; ...

2016-11-30

We present that lithium-sulfur (Li-S) battery is a promising energy storage technology to replace lithium ion batteries for higher energy density and lower cost. Dissolution of lithium polysulfide intermediates in conventional Li-S electrolytes is known as one of the key technical barriers to the development of Li-S, because it promotes redistribution and irreversible deposition of Li 2S, and also forces large amounts of electrolyte to be used, shortening cycling life and driving down cell energy density. Recently, dimethyl disulfide as a functional co-solvent has been demonstrated to show an alternate electrochemical reaction pathway for sulfur cathodes by the formation ofmore » dimethyl polysulfides and lithium organosulfides as intermediates and reduction products. In this work, comprehensive studies show that this new pathway not only provides high capacity but also enables excellent capacity retention through a built-in automatic discharge shutoff mechanism by tuning carbon/sulfur ratio in sulfur cathodes to reduce unfavorable Li 2S formation. Furthermore, this new electrolyte system is also found to enable high capacity of high-sulfur-loading cathodes with low electrolyte/sulfur (E/S) ratios, such as a stable specific capacity of around 1000 mAh g -1 using a low electrolyte amount (i.e, E/S ratio of 5 mL g -1) and highsulfur-loading (4 mg cm -2) cathodes. This electrolyte system almost doubles the capacity obtained with conventional electrolytes under the same harsh conditions. In conclusion, these results highlight the practical potential of this electrolyte system to enable high-energy-density Li-S batteries.« less

High capacity of lithium-sulfur batteries at low electrolyte/sulfur ratio enabled by an organosulfide containing electrolyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Shuru; Gao, Yue; Yu, Zhaoxin

We present that lithium-sulfur (Li-S) battery is a promising energy storage technology to replace lithium ion batteries for higher energy density and lower cost. Dissolution of lithium polysulfide intermediates in conventional Li-S electrolytes is known as one of the key technical barriers to the development of Li-S, because it promotes redistribution and irreversible deposition of Li 2S, and also forces large amounts of electrolyte to be used, shortening cycling life and driving down cell energy density. Recently, dimethyl disulfide as a functional co-solvent has been demonstrated to show an alternate electrochemical reaction pathway for sulfur cathodes by the formation ofmore » dimethyl polysulfides and lithium organosulfides as intermediates and reduction products. In this work, comprehensive studies show that this new pathway not only provides high capacity but also enables excellent capacity retention through a built-in automatic discharge shutoff mechanism by tuning carbon/sulfur ratio in sulfur cathodes to reduce unfavorable Li 2S formation. Furthermore, this new electrolyte system is also found to enable high capacity of high-sulfur-loading cathodes with low electrolyte/sulfur (E/S) ratios, such as a stable specific capacity of around 1000 mAh g -1 using a low electrolyte amount (i.e, E/S ratio of 5 mL g -1) and highsulfur-loading (4 mg cm -2) cathodes. This electrolyte system almost doubles the capacity obtained with conventional electrolytes under the same harsh conditions. In conclusion, these results highlight the practical potential of this electrolyte system to enable high-energy-density Li-S batteries.« less

40 CFR 424.67 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... control technology. 424.67 Section 424.67 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Electrolytic... reduction attainable by the application of the best conventional pollutant control technology. Except as...

Tin, Bismuth, and Tin-Bismuth Alloy Electrodeposition from Chlorometalate Salts in Deep Eutectic Solvents.

PubMed

Vieira, Luciana; Burt, Jennifer; Richardson, Peter W; Schloffer, Daniel; Fuchs, David; Moser, Alwin; Bartlett, Philip N; Reid, Gillian; Gollas, Bernhard

2017-06-01

The electrodeposition of tin, bismuth, and tin-bismuth alloys from Sn II and Bi III chlorometalate salts in the choline chloride/ethylene glycol (1:2 molar ratio) deep eutectic solvent was studied on glassy carbon and gold by cyclic voltammetry, rotating disc voltammetry, and chronoamperometry. The Sn II -containing electrolyte showed one voltammetric redox process corresponding to Sn II /Sn 0 . The diffusion coefficient of [SnCl 3 ] - , detected as the dominating species by Raman spectroscopy, was determined from Levich and Cottrell analyses. The Bi III -containing electrolyte showed two voltammetric reduction processes, both attributed to Bi III /Bi 0 . Dimensionless current/time transients revealed that the electrodeposition of both Sn and Bi on glassy carbon proceeded by 3D-progressive nucleation at a low overpotential and changed to instantaneous at higher overpotentials. The nucleation rate of Bi on glassy carbon was considerably smaller than that of Sn. Elemental Sn and Bi were electrodeposited on Au-coated glass slides from their respective salt solutions, as were Sn-Bi alloys from a 2:1 Sn II /Bi III solution. The biphasic Sn-Bi alloys changed from a Bi-rich composition to a Sn-rich composition by making the deposition potential more negative.

Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte

PubMed Central

Huang, K.; Bi, K.; Liang, C.; Lin, S.; Zhang, R.; Wang, W. J.; Tang, H. L.; Lei, M.

2015-01-01

A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells. PMID:26100367

Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte

NASA Astrophysics Data System (ADS)

Huang, K.; Bi, K.; Liang, C.; Lin, S.; Zhang, R.; Wang, W. J.; Tang, H. L.; Lei, M.

2015-06-01

A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells.

Fabrication of free-standing hierarchical carbon nanofiber/graphene oxide/polyaniline films for supercapacitors.

PubMed

Xu, Dongdong; Xu, Qun; Wang, Kaixi; Chen, Jun; Chen, Zhimin

2014-01-08

A hierarchical high-performance electrode with nanoacanthine-style polyaniline (PANI) deposited onto a carbon nanofiber/graphene oxide (CNF/GO) template was successfully prepared via an in situ polymerization process. The morphology analysis shows that introducing one-dimensional (1D) CNF could significantly decrease/inhibit the staking of laminated GO to form an open-porous CNF/GO architecture. Followed with in situ facial deposition of PANI, the as-synthesized PANI modified CNF/GO exhibits three-dimensional (3D) hierarchical layered nanoarchitecture, which favors the diffusion of the electrolyte ions into the inner region of active materials. The hierarchical free-standing electrodes were directly fabricated into sandwich structured supercapacitors using 1 M H2SO4 as the electrolyte showing a significant specific capacitance of 450.2 F/g at the voltage scan rate of 10 mV/s. The electrochemical properties of the hierarchical structure can be further improved by a reduction procedure of GO before the deposition of PANI.

Usage of Neural Network to Predict Aluminium Oxide Layer Thickness

PubMed Central

Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

2015-01-01

This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A·dm−2 and 3 A·dm−2 for creating aluminium oxide layer. PMID:25922850

Usage of neural network to predict aluminium oxide layer thickness.

PubMed

Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

2015-01-01

This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A · dm(-2) and 3 A · dm(-2) for creating aluminium oxide layer.

A new anion receptor for improving the interface between lithium- and manganese-rich layered oxide cathode and the electrolyte

DOE PAGES

Ma, Yulin; Zhou, Yan; Du, Chunyu; ...

2017-02-15

Surface degradation on cycled lithium-ion battery cathode particles is governed not only by intrinsic thermodynamic properties of the material but also, oftentimes more predominantly, by the side reactions with the electrolytic solution. A superior electrolyte inhibits these undesired side reactions on the cathode and at the electrolyte interface, which consequently minimizes the deterioration of the cathode surface. The present study investigates a new boron-based anion receptor, tris(2,2,2-trifluoroethyl)borate (TTFEB), as an electrolyte additive in cells containing a lithium- and manganese-rich layered oxide cathode, Li 1.16Ni 0.2Co 0.1Mn 0.54O 2. Our electrochemical studies demonstrate that the cycling performance and Coulombic efficiency aremore » significantly improved because of the additive, in particular, under elevated temperature conditions. Spectroscopic analyses revealed that the addition of 0.5 wt % TTFEB is capable of reducing the content of lithium-containing inorganic species within the cathode-electrolyte interphase layer and minimizing the reduction of tetravalent Mn4+ at the cathode surface. Furthermore, our work introduces a novel additive highly effective in improving lithium-ion battery performance, highlights the importance in preserving the surface properties of cathode materials, and provides new insights on the working mechanism of electrolyte additives.« less

Preparation of redox polymer cathodes for thin film rechargeable batteries

DOEpatents

Skotheim, T.A.; Lee, H.S.; Okamoto, Yoshiyuki.

1994-11-08

The present invention relates to the manufacture of thin film solid state electrochemical devices using composite cathodes comprising a redox polymer capable of undergoing oxidation and reduction, a polymer solid electrolyte and conducting carbon. The polymeric cathode material is formed as a composite of radiation crosslinked polymer electrolytes and radiation crosslinked redox polymers based on polysiloxane backbones with attached organosulfur side groups capable of forming sulfur-sulfur bonds during electrochemical oxidation.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, M.W.; George, W.A.

1991-06-18

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg[sub 2]Cl[sub 2] employing as the electrolyte solution a mixture of HCl and H[sub 2]O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H[sub 2]O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds. 3 figures.

Recovery of mercury from mercury compounds via electrolytic methods

DOEpatents

Grossman, M.W.; George, W.A.

1989-11-07

A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg[sub 2]Cl[sub 2] employing as the electrolyte solution a mixture of HCl and H[sub 2]O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H[sub 2]O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds. 3 figs.

Combination of an electrolytic pretreatment unit with secondary water reclamation processes

NASA Technical Reports Server (NTRS)

Wells, G. W.; Bonura, M. S.

1973-01-01

The design and fabrication of a flight concept prototype electrolytic pretreatment unit (EPU) and of a contractor-furnished air evaporation unit (AEU) are described. The integrated EPU and AEU potable water recovery system is referred to as the Electrovap and is capable of processing the urine and flush water of a six-man crew. Results of a five-day performance verification test of the Electrovap system are presented and plans are included for the extended testing of the Electrovap to produce data applicable to the combination of electrolytic pretreatment with most final potable water recovery systems. Plans are also presented for a program to define the design requirements for combining the electrolytic pretreatment unit with a reverse osmosis final processing unit.

Top Ten Reasons for DEOX as a Front End to Pyroprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

B.R. Westphal; K.J. Bateman; S.D. Herrmann

A front end step is being considered to augment chopping during the treatment of spent oxide fuel by pyroprocessing. The front end step, termed DEOX for its emphasis on decladding via oxidation, employs high temperatures to promote the oxidation of UO2 to U3O8 via an oxygen carrier gas. During oxidation, the spent fuel experiences a 30% increase in lattice structure volume resulting in the separation of fuel from cladding with a reduced particle size. A potential added benefit of DEOX is the removal of fission products, either via direct release from the broken fuel structure or via oxidation and volatilizationmore » by the high temperature process. Fuel element chopping is the baseline operation to prepare spent oxide fuel for an electrolytic reduction step. Typical chopping lengths range from 1 to 5 mm for both individual elements and entire assemblies. During electrolytic reduction, uranium oxide is reduced to metallic uranium via a lithium molten salt. An electrorefining step is then performed to separate a majority of the fission products from the recoverable uranium. Although DEOX is based on a low temperature oxidation cycle near 500oC, additional conditions have been tested to distinguish their effects on the process.[1] Both oxygen and air have been utilized during the oxidation portion followed by vacuum conditions to temperatures as high as 1200oC. In addition, the effects of cladding on fission product removal have also been investigated with released fuel to temperatures greater than 500oC.« less

Metallization pattern on solid electrolyte or porous support of sodium battery process

DOEpatents

Kim, Jin Yong; Li, Guosheng; Lu, Xiaochuan; Sprenkle, Vincent L.; Lemmon, John P.

2016-05-31

A new battery configuration and process are detailed. The battery cell includes a solid electrolyte configured with an engineered metallization layer that distributes sodium across the surface of the electrolyte extending the active area of the cathode in contact with the anode during operation. The metallization layer enhances performance, efficiency, and capacity of sodium batteries at intermediate temperatures at or below about 200.degree. C.

Polymeric electrolytes based on hydrosilyation reactions

DOEpatents

Kerr, John Borland [Oakland, CA; Wang, Shanger [Fairfield, CA; Hou, Jun [Painted Post, NY; Sloop, Steven Edward [Berkeley, CA; Han, Yong Bong [Berkeley, CA; Liu, Gao [Oakland, CA

2006-09-05

New polymer electrolytes were prepared by in situ cross-linking of allyl functional polymers based on hydrosilation reaction using a multifunctional silane cross-linker and an organoplatinum catalyst. The new cross-linked electrolytes are insoluble in organic solvent and show much better mechanical strength. In addition, the processability of the polymer electrolyte is maintained since the casting is finished well before the gel formation.

Superior Performance of a Lithium-Sulfur Battery Enabled by a Dimethyl Trisulfide Containing Electrolyte

DOE PAGES

Chen, Shuru; Wang, Daiwei; Zhao, Yuming; ...

2018-04-26

The lithium-sulfur (Li-S) battery offers a high theoretical energy density of ≈2600 Wh/kg -1 and low cost, positioning it as a promising candidate for next-generation battery technology. However, problems including disastrous Li polysulfides dissolution and irreversible Li 2S deposition have severely retarded the development of Li-S batteries. To solve these issues, we recently reported a functional dimethyl disulfide (DMDS)-containing electrolyte that promoted an alternate electrochemical reaction pathway for sulfur cathodes by a formation of dimethyl polysulfides and Li organosulfides as intermediates and reduction products, leading to significantly boosted Li-S cell capacity with improved cycling reversibility and stability. Here in thismore » work, dimethyl trisulfide (DMTS), a primary discharge-charge intermediate in the DMDS-containing electrolyte, which is also a commercially available reagent, was further investigated as a co-solvent in functional electrolytes for Li-S batteries. Due to the higher theoretical capacity of DMTS and its better reactivity with Li 2S than DMDS, a 25 vol% DMTS-containing electrolyte enables Li-S batteries with even higher cell capacity and improved cycling performance than using previous optimal 50 vol% DMDS-containing electrolyte.« less

Superior Performance of a Lithium-Sulfur Battery Enabled by a Dimethyl Trisulfide Containing Electrolyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Shuru; Wang, Daiwei; Zhao, Yuming

The lithium-sulfur (Li-S) battery offers a high theoretical energy density of ≈2600 Wh/kg -1 and low cost, positioning it as a promising candidate for next-generation battery technology. However, problems including disastrous Li polysulfides dissolution and irreversible Li 2S deposition have severely retarded the development of Li-S batteries. To solve these issues, we recently reported a functional dimethyl disulfide (DMDS)-containing electrolyte that promoted an alternate electrochemical reaction pathway for sulfur cathodes by a formation of dimethyl polysulfides and Li organosulfides as intermediates and reduction products, leading to significantly boosted Li-S cell capacity with improved cycling reversibility and stability. Here in thismore » work, dimethyl trisulfide (DMTS), a primary discharge-charge intermediate in the DMDS-containing electrolyte, which is also a commercially available reagent, was further investigated as a co-solvent in functional electrolytes for Li-S batteries. Due to the higher theoretical capacity of DMTS and its better reactivity with Li 2S than DMDS, a 25 vol% DMTS-containing electrolyte enables Li-S batteries with even higher cell capacity and improved cycling performance than using previous optimal 50 vol% DMDS-containing electrolyte.« less

Li 2OHCl crystalline electrolyte for stable metallic lithium anodes

DOE PAGES

Hood, Zachary D.; Wang, Hui; Samuthira Pandian, Amaresh; ...

2016-01-22

In a classic example of stability from instability, we show that Li 2OHCl solid electrolyte forms a stable solid electrolyte interface (SEI) with metallic lithium anode. The Li 2OHCl solid electrolyte can be readily achieved through simple mixing of air-stable LiOH and LiCl precursors with a mild processing temperature under 400 °C. Additionally, we show that continuous, dense Li 2OHCl membranes can be fabricated at temperatures less than 400 °C, standing in great contrast to current processing temperatures of over 1600 °C for most oxide-based solid electrolytes. The ionic conductivity and Arrhenius activation energy were explored for the LiOH-LiCl systemmore » of crystalline solid electrolytes where Li 2OHCl with increased crystal defects was found to have the highest ionic conductivity and reasonable Arrhenius activation energy. The Li 2OHCl solid electrolyte displays stability against metallic lithium, even in extreme conditions past the melting point of lithium metal. Furthermore, to understand this excellent stability, we show that SEI formation is critical in stabilizing the interface between metallic lithium and the Li 2OHCl solid electrolyte.« less

Carbon dioxide electrolysis with solid oxide electrolyte cells for oxygen recovery in life support systems

NASA Technical Reports Server (NTRS)

Isenberg, Arnold O.; Cusick, Robert J.

1988-01-01

The direct electrochemical reduction of carbon dioxide (CO2) is achieved without catalysts and at sufficiently high temperatures to avoid carbon formation. The tubular electrolysis cell consists of thin layers of anode, electrolyte, cathode and cell interconnection. The electrolyte is made from yttria-stabilized zirconia which is an oxygen ion conductor at elevated temperatures. Anode and cell interconnection materials are complex oxides and are electronic conductors. The cathode material is a composite metal-ceramic structure. Cell performance characteristics have been determined using varying feed gas compositions and degrees of electrochemical decomposition. Cell test data are used to project the performance of a three-person CO2-electrolysis breadboard system.

Organic radicals for the enhancement of oxygen reduction reaction in Li-O2 batteries.

PubMed

Tesio, A Y; Blasi, D; Olivares-Marín, M; Ratera, I; Tonti, D; Veciana, J

2015-12-25

We examine for the first time the ability of inert carbon free-radicals as soluble redox mediators to catalyze and enhance the oxygen reduction reaction in a (TEGDME)-based electrolyte. We demonstrate that the tris(2,4,6-trichlorophenyl)methyl (TTM) radical is capable of chemically favoring the oxygen reduction reaction improving significantly the Li-O2 battery performance.

Tris(trimethylsilyl) Phosphite as an Efficient Electrolyte Additive To Improve the Surface Stability of Graphite Anodes.

PubMed

Yim, Taeeun; Han, Young-Kyu

2017-09-27

Tris(trimethylsilyl) phosphite (TMSP) has received considerable attention as a functional additive for various cathode materials in lithium-ion batteries, but the effect of TMSP on the surface stability of a graphite anode has not been studied. Herein, we demonstrate that TMSP serves as an effective solid electrolyte interphase (SEI)-forming additive for graphite anodes in lithium-ion batteries (LIBs). TMSP forms SEI layers by chemical reactions between TMSP and a reductively decomposed ethylene carbonate (EC) anion, which is strikingly different from the widely known mechanism of the SEI-forming additives. TMSP is stable under cathodic polarization, but it reacts chemically with radical anion intermediates derived from the electrochemical reduction of the carbonate solvents to generate a stable SEI layer. These TMSP-derived SEI layers improve the interfacial stability of the graphite anode, resulting in a retention of 96.8% and a high Coulombic efficiency of 95.2%. We suggest the use of TMSP as a functional additive that effectively stabilizes solid electrolyte interfaces of both the anode and cathode in lithium-ion batteries.

Lithium sulfur batteries and electrolytes and sulfur cathodes thereof

DOEpatents

Visco, Steven J.; Goncharenko, Nikolay; Nimon, Vitaliy; Petrov, Alexei; Nimon, Yevgeniy S.; De Jonghe, Lutgard C.; Katz, Bruce D.; Loginova, Valentina

2017-05-23

Lithium sulfur battery cells that use water as an electrolyte solvent provide significant cost reductions. Electrolytes for the battery cells may include water solvent for maintaining electroactive sulfur species in solution during cell discharge and a sufficient amount of a cycle life-enhancing compound that facilitates charging at the cathode. The combination of these two components enhances one or more of the following cell attributes: energy density, power density and cycle life. For instance, in applications where cost per Watt-Hour (Wh) is paramount, such as grid storage and traction applications, the use of an aqueous electrolyte in combination with inexpensive sulfur as the cathode active material can be a key enabler for the utility and automotive industries, for example, providing a cost effective and compact solution for load leveling, electric vehicles and renewable energy storage. Sulfur cathodes, and methods of fabricating lithium sulfur cells, in particular for loading lithium sulfide into the cathode structures, provide further advantages.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baskin, Artem; Prendergast, David

In this paper, we reveal the general mechanisms of partial reduction of multivalent complex cations in conditions specific for the bulk solvent and in the vicinity of the electrified metal electrode surface and disclose the factors affecting the reductive stability of electrolytes for multivalent electrochemistry. Using a combination of ab initio techniques, we clarify the relation between the reductive stability of contact-ion pairs comprising a multivalent cation and a complex anion, their solvation structures, solvent dynamics, and the electrode overpotential. We found that for ion pairs with multiple configurations of the complex anion and the Mg cation whose available orbitalsmore » are partially delocalized over the molecular complex and have antibonding character, the primary factor of the reductive stability is the shape factor of the solvation sphere of the metal cation center and the degree of the convexity of a polyhedron formed by the metal cation and its coordinating atoms. We focused specifically on the details of Mg (II) bis(trifluoromethanesulfonyl)imide in diethylene glycol dimethyl ether (Mg(TFSI) 2)/diglyme) and its singly charged ion pair, MgTFSI +. In particular, we found that both stable (MgTFSI) + and (MgTFSI) 0 ion pairs have the same TFSI configuration but drastically different solvation structures in the bulk solution. This implies that the MgTFSI/dyglyme reductive stability is ultimately determined by the relative time scale of the solvent dynamics and electron transfer at the Mg–anode interface. In the vicinity of the anode surface, steric factors and hindered solvent dynamics may increase the reductive stability of (MgTFSI) + ion pairs at lower overpotential by reducing the metal cation coordination, in stark contrast to the reduction at high overpotential accompanied by TFSI decomposition. By examining other solute/solvent combinations, we conclude that the electrolytes with highly coordinated Mg cation centers are more prone to reductive instability due to the chemical decomposition of the anion or solvent molecules. Finally, the obtained findings disclose critical factors for stable electrolyte design and show the role of interfacial phenomena in reduction of multivalent ions.« less

Process to produce lithium-polymer batteries

DOEpatents

MacFadden, Kenneth Orville

1998-01-01

A polymer bonded sheet product suitable for use as an electrode in a non-aqueous battery system. A porous electrode sheet is impregnated with a solid polymer electrolyte, so as to diffuse into the pores of the electrode. The composite is allowed to cool, and the electrolyte is entrapped in the porous electrode. The sheet products composed have the solid polymer electrolyte composition diffused into the active electrode material by melt-application of the solid polymer electrolyte composition into the porous electrode material sheet. The solid polymer electrolyte is maintained at a temperature that allows for rapid diffusion into the pores of the electrode. The composite electrolyte-electrode sheets are formed on current collectors and can be coated with solid polymer electrolyte prior to battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte coating has low resistance.

Prospects for reducing the processing cost of lithium ion batteries

DOE PAGES

Wood III, David L.; Li, Jianlin; Daniel, Claus

2014-11-06

A detailed processing cost breakdown is given for lithium-ion battery (LIB) electrodes, which focuses on: elimination of toxic, costly N-methylpyrrolidone (NMP) dispersion chemistry; doubling the thicknesses of the anode and cathode to raise energy density; and, reduction of the anode electrolyte wetting and SEI-layer formation time. These processing cost reduction technologies generically adaptable to any anode or cathode cell chemistry and are being implemented at ORNL. This paper shows step by step how these cost savings can be realized in existing or new LIB manufacturing plants using a baseline case of thin (power) electrodes produced with NMP processing and amore » standard 10-14-day wetting and formation process. In particular, it is shown that aqueous electrode processing can cut the electrode processing cost and energy consumption by an order of magnitude. Doubling the thickness of the electrodes allows for using half of the inactive current collectors and separators, contributing even further to the processing cost savings. Finally wetting and SEI-layer formation cost savings are discussed in the context of a protocol with significantly reduced time. These three benefits collectively offer the possibility of reducing LIB pack cost from $502.8 kWh-1-usable to $370.3 kWh-1-usable, a savings of $132.5/kWh (or 26.4%).« less

Friction welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Ray, Siba P.; Rapp, Robert A.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor and a ceramic electrode body connected by a friction weld between a portion of the body having a level of free metal or metal alloy sufficient to effect such a friction weld and a portion of the metal conductor.

Titania nanotube powders obtained by rapid breakdown anodization in perchloric acid electrolytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, Saima, E-mail: saima.ali@aalto.fi; Hannula, Simo-Pekka

Titania nanotube (TNT) powders are prepared by rapid break down anodization (RBA) in a 0.1 M perchloric acid (HClO{sub 4}) solution (Process 1), and ethylene glycol (EG) mixture with HClO{sub 4} and water (Process 2). A study of the as-prepared and calcined TNT powders obtained by both processes is implemented to evaluate and compare the morphology, crystal structure, specific surface area, and the composition of the nanotubes. Longer TNTs are formed in Process 1, while comparatively larger pore diameter and wall thickness are obtained for the nanotubes prepared by Process 2. The TNTs obtained by Process 1 are converted tomore » nanorods at 350 °C, while nanotubes obtained by Process 2 preserve tubular morphology till 350 °C. In addition, the TNTs prepared by an aqueous electrolyte have a crystalline structure, whereas the TNTs obtained by Process 2 are amorphous. Samples calcined till 450 °C have XRD peaks from the anatase phase, while the rutile phase appears at 550 °C for the TNTs prepared by both processes. The Raman spectra also show clear anatase peaks for all samples except the as-prepared sample obtained by Process 2, thus supporting the XRD findings. FTIR spectra reveal the presence of O-H groups in the structure for the TNTs obtained by both processes. However, the presence is less prominent for annealed samples. Additionally, TNTs obtained by Process 2 have a carbonaceous impurity present in the structure attributed to the electrolyte used in that process. While a negligible weight loss is typical for TNTs prepared from aqueous electrolytes, a weight loss of 38.6% in the temperature range of 25–600 °C is found for TNTs prepared in EG electrolyte (Process 2). A large specific surface area of 179.2 m{sup 2} g{sup −1} is obtained for TNTs prepared by Process 1, whereas Process 2 produces nanotubes with a lower specific surface area. The difference appears to correspond to the dimensions of the nanotubes obtained by the two processes. - Graphical abstract: Titania nanotube powders prepared by Process 1 and Process 2 have different crystal structure and specific surface area. - Highlights: • Titania nanotube (TNT) powder is prepared in low water organic electrolyte. • Characterization of TNT powders prepared from aqueous and organic electrolyte. • TNTs prepared by Process 1 are crystalline with higher specific surface area. • TNTs obtained by Process 2 have carbonaceous impurities in the structure.« less

Electrolyte Loss Tendencies of Primary Silver-Zinc Cells

NASA Technical Reports Server (NTRS)

Thaller, Lawrence H.; Juvinall, Gordon L.

1997-01-01

Since silver zinc cells are not hermetically sealed, care must be taken to prevent the loss of electrolyte which can result in shorting paths within the battery box. Prelaunch battery processing is important in being able to minimize any problems with expelled electrolyte.

Functionally Graded Bismuth Oxide/Zirconia Bilayer Electrolytes for High-Performance Intermediate-Temperature Solid Oxide Fuel Cells (IT-SOFCs).

PubMed

Joh, Dong Woo; Park, Jeong Hwa; Kim, Doyeub; Wachsman, Eric D; Lee, Kang Taek

2017-03-15

A functionally graded Bi 1.6 Er 0.4 O 3 (ESB)/Y 0.16 Zr 0.84 O 1.92 (YSZ) bilayer electrolyte is successfully developed via a cost-effective screen printing process using nanoscale ESB powders on the tape-cast NiO-YSZ anode support. Because of the highly enhanced oxygen incorporation process at the cathode/electrolyte interface, a novel bilayer solid oxide fuel cell (SOFC) yields extremely high power density of ∼2.1 W cm -2 at 700 °C, which is a 2.4 times increase compared to that of the YSZ single electrolyte SOFC.

Investigation of a novel ternary electrolyte based on dimethyl sulfite and lithium difluoromono(oxalato)borate for lithium ion batteries

NASA Astrophysics Data System (ADS)

Chen, Renjie; Zhu, Lu; Wu, Feng; Li, Li; Zhang, Rong; Chen, Shi

2014-01-01

Lithium difluoromono(oxalato)borate (LiODFB) has been used as a novel lithium salt for battery in recent studies. In this study, a series of novel electrolytes has been prepared by adding 30 vol% dimethyl sulfite (DMS) or dimethyl carbonate (DMC) as co-solvent into an ethylene carbonate (EC)/ethyl methyl carbonate (EMC) + LiX mixture, in which the LiX could be LiClO4, LiODFB, LiBOB, LiTFSI, or LiCF3SO3. These ternary electrolytes have been investigated for use in lithium ion batteries. FT-IR spectroscopy analysis shows that characteristic functional groups (-CO3, -SO3) undergo red-shift or blue-shift with the addition of different lithium salts. The LiODFB-EC/EMC/DMS electrolyte exhibits high ionic conductivity, which is mainly because of the low melting point of DMS, and LiODFB possessing high solubility. The Li/MCMB cells containing this novel electrolyte exhibit high capacities, good cycling performance, and excellent rate performance. These performances are probably because both LiODFB and DMS can assist in the formation of SEI films by reductive decomposition. Additionally, the discharge capacity of Li/LiCoO2 half cell containing LiODFB-EC/EMC/DMS electrolyte is 130.9 mAh g-1 after 50 cycles, and it is very comparable with the standard-commercial electrolyte. The results show that this study produces a promising electrolyte candidate for lithium ion batteries.

Density Functional Theory Research into the Reduction Mechanism for the Solvent/Additive in a Sodium-Ion Battery.

PubMed

Liu, Qi; Mu, Daobin; Wu, Borong; Wang, Lei; Gai, Liang; Wu, Feng

2017-02-22

The solid-electrolyte interface (SEI) film in a sodium-ion battery is closely related to capacity fading and cycling stability of the battery. However, there are few studies on the SEI film of sodium-ion batteries and the mechanism of SEI film formation is unclear. The mechanism for the reduction of ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), ethylene sulfite (ES), 1,3-propylene sulfite (PS), and fluorinated ethylene carbonate (FEC) is studied by DFT. The reaction activation energies, Gibbs free energies, enthalpies, and structures of the transition states are calculated. It is indicated that VC, ES, and PS additives in the electrolyte are all easier to form organic components in the anode SEI film by one-electron reduction. The priority of one-electron reduction to produce organic SEI components is in the order of VC>PC>EC; two-electron reduction to produce the inorganic Na 2 CO 3 component is different and follows the order of EC>PC>VC. Two-electron reduction for sulfites ES and PS to form inorganic Na 2 SO 3 is harder than that of carbonate ester reduction. It is also suggested that the one- and two-electron reductive decomposition pathway for FEC is more feasible to produce inorganic NaF components. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoengineered membrane electrode assembly interface

DOEpatents

Song, Yujiang; Shelnutt, John A

2013-08-06

A membrane electrode structure suitable for use in a membrane electrode assembly (MEA) that comprises membrane-affixed metal nanoparticles whose formation is controlled by a photochemical process that controls deposition of the metal nanoparticles using a photocatalyst integrated with a polymer electrolyte membrane, such as an ionomer membrane. Impregnation of the polymer membrane with the photocatalyst prior to metal deposition greatly reduces the required amount of metal precursor in the deposition reaction solution by restricting metal reduction substantially to the formation of metal nanoparticles affixed on or near the surface of the polymer membrane with minimal formation of metallic particles not directly associated with the membrane.

Luminescent Tellurium-Doped Cadmium Sulfide Electrodes as Probes of Semiconductor Excited-State Deactivation Processes in Photoelectrochemical Cells.

DTIC Science & Technology

1980-08-12

photocurrent and emission intensity. Whereas CdS:Te electrochemistry consisted of oxidation of an electrolyte 2+ reductant, ZnO underwent photoanodic...employed n- and 1 3 2,3 3 3,4p-type GaPl’ n-type ZnO , n-type CdS , and n- and p-type GaAs. We have focussed our attention recently on n-type, tellurium...should point out that our treatment of Or and 0x is not without precedent. Both GaP- and ZnO -based PECs have been examined in this regard.l12 The

A supramolecular gel electrolyte formed from amide based co-gelator for quasi-solid-state dye-sensitized solar cell with boosted electron kinetic processes

NASA Astrophysics Data System (ADS)

Huo, Zhipeng; Wang, Lu; Tao, Li; Ding, Yong; Yi, Jinxin; Alsaedi, Ahmed; Hayat, Tasawar; Dai, Songyuan

2017-08-01

A supramolecular gel electrolyte (Tgel > 100 °C) is formed from N,N‧-1,8-octanediylbis-dodecanamide and iodoacetamide as two-component co-gelator, and introduced into the quasi-solid-state dye-sensitized solar cells (QS-DSSCs). The different morphologies of microscopic network between two-component and single-component gel electrolytes have influence on the diffusion of redox couple in gel electrolytes and further affect the electron kinetic processes in QS-DSSCs. Compared with the single-component gel electrolyte, the two-component gel electrolyte has less compact gel network and weaker steric hindrance effect, which provides more effective charge transport channel for the diffusion of I3/I- redox couple. Meanwhile, the sbnd NH2 groups of iodoacetamide molecules interact with Li+ and I3-, which also accelerate the transport of I3-/I- and decrease in the I3- concentration in the TiO2/electrolyte interface. As a result, nearly a 12% improvement in short-circuit photocurrent density (Jsc) and much higher open circuit potential (Voc) are found in the two-component gel electrolyte based QS-DSSC. Consequently, the QS-DSSC based on the supramolecular gel electrolyte obtains a 17% enhancement in the photoelectric conversion efficiency (7.32%) in comparison with the QS-DSSC based on the single-component gel electrolyte (6.24%). Furthermore, the degradations of these QS-DSSCs are negligible after one sun light soaking with UV cutoff filter at 50 °C for 1000 h.

Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

NASA Astrophysics Data System (ADS)

Fleetwood, James D.

Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 °C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak power densities as high as 520 mW/cm2 at 800 °C for YSZ and 350 mW/cm 2 at 800 °C for YSZ/GDC bilayer electrolytes.

Impact of electroviscosity on the hydraulic conductance of the bordered pit membrane: a theoretical investigation.

PubMed

Santiago, Michael; Pagay, Vinay; Stroock, Abraham D

2013-10-01

In perfusion experiments, the hydraulic conductance of stem segments ( ) responds to changes in the properties of the perfusate, such as the ionic strength ( ), pH, and cationic identity. We review the experimental and theoretical work on this phenomenon. We then proceed to explore the hypothesis that electrokinetic effects in the bordered pit membrane (BPM) contribute to this response. In particular, we develop a model based on electroviscosity in which hydraulic conductance of an electrically charged porous membrane varies with the properties of the electrolyte. We use standard electrokinetic theory, coupled with measurements of electrokinetic properties of plant materials from the literature, to determine how the conductance of BPMs, and therefore , may change due to electroviscosity. We predict a nonmonotonic variation of with with a maximum reduction of 18%. We explore how this reduction depends on the characteristics of the sap and features of the BPM, such as pore size, density of chargeable sites, and their dissociation constant. Our predictions are consistent with changes in observed for physiological values of sap and pH. We conclude that electroviscosity is likely responsible, at least partially, for the electrolyte dependence of conductance through pits and that electroviscosity may be strong enough to play an important role in other transport processes in xylem. We conclude by proposing experiments to differentiate the impact of electroviscosity on from that of other proposed mechanisms.

Stabilizing lithium metal using ionic liquids for long-lived batteries

PubMed Central

Basile, A.; Bhatt, A. I.; O'Mullane, A. P.

2016-01-01

Suppressing dendrite formation at lithium metal anodes during cycling is critical for the implementation of future lithium metal-based battery technology. Here we report that it can be achieved via the facile process of immersing the electrodes in ionic liquid electrolytes for a period of time before battery assembly. This creates a durable and lithium ion-permeable solid–electrolyte interphase that allows safe charge–discharge cycling of commercially applicable Li|electrolyte|LiFePO4 batteries for 1,000 cycles with Coulombic efficiencies >99.5%. The tailored solid–electrolyte interphase is prepared using a variety of electrolytes based on the N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide room temperature ionic liquid containing lithium salts. The formation is both time- and lithium salt-dependant, showing dynamic morphology changes, which when optimized prevent dendrite formation and consumption of electrolyte during cycling. This work illustrates that a simple, effective and industrially applicable lithium metal pretreatment process results in a commercially viable cycle life for a lithium metal battery. PMID:27292652

Fast formation cycling for lithium ion batteries

DOE PAGES

An, Seong Jin; Li, Jianlin; Du, Zhijia; ...

2017-01-09

The formation process for lithium ion batteries typically takes several days or more, and it is necessary for providing a stable solid electrolyte interphase on the anode (at low potentials vs. Li/Li +) for preventing irreversible consumption of electrolyte and lithium ions. An analogous layer known as the cathode electrolyte interphase layer forms at the cathode at high potentials vs. Li/Li +. However, several days, or even up to a week, of these processes result in either lower LIB production rates or a prohibitively large size of charging-discharging equipment and space (i.e. excessive capital cost). In this study, a fastmore » and effective electrolyte interphase formation protocol is proposed and compared with an Oak Ridge National Laboratory baseline protocol. Graphite, NMC 532, and 1.2 M LiPF 6 in ethylene carbonate: diethyl carbonate were used as anodes, cathodes, and electrolytes, respectively. Finally, results from electrochemical impedance spectroscopy show the new protocol reduced surface film (electrolyte interphase) resistances, and 1300 aging cycles show an improvement in capacity retention.« less

Roles of Cationic and Elemental Calcium in the Electro-Reduction of Solid Metal Oxides in Molten Calcium Chloride

NASA Astrophysics Data System (ADS)

Qiu, Guohong; Jiang, Kai; Ma, Meng; Wang, Dihua; Jin, Xianbo; Chen, George Z.

2007-06-01

Previous work, mainly from this research group, is re-visited on electrochemical reduction of solid metal oxides, in the form of compacted powder, in molten CaCl2, aiming at further understanding of the roles of cationic and elemental calcium. The discussion focuses on six aspects: 1.) debate on two mechanisms proposed in the literature, i. e. electro-metallothermic reduction and electro-reduction (or electro-deoxidation), for the electrolytic removal of oxygen from solid metals or metal oxides in molten CaCl2; 2.) novel metallic cavity working electrodes for electrochemical investigations of compacted metal oxide powders in high temperature molten salts assisted by a quartz sealed Ag/AgCl reference electrode (650 ºC- 950 ºC); 3.) influence of elemental calcium on the background current observed during electrolysis of solid metal oxides in molten CaCl2; 4.) electrochemical insertion/ inclusion of cationic calcium into solid metal oxides; 5.) typical features of cyclic voltammetry and chronoamperometry (potentiostatic electrolysis) of metal oxide powders in molten CaCl2; and 6.) some kinetic considerations on the electrolytic removal of oxygen.

Process for producing silicon

DOEpatents

Olson, J.M.; Carleton, K.L.

1982-06-10

A process of producing silicon includes forming an alloy of copper and silicon and positioning the alloy in a dried, molten salt electrolyte to form a solid anode structure therein. An electrically conductive cathode is placed in the electrolyte for plating silicon thereon. The electrolyte is then purified to remove dissolved oxides. Finally, an electrical potential is applied between the anode and cathode in an amount sufficient to form substantially pure silicon on the cathode in the form of substantially dense, coherent deposits.

Process for producing silicon

DOEpatents

Olson, Jerry M.; Carleton, Karen L.

1984-01-01

A process for producing silicon includes forming an alloy of copper and silicon and positioning the alloy in a dried, molten salt electrolyte to form a solid anode structure therein. An electrically conductive cathode is placed in the electrolyte for plating silicon thereon. The electrolyte is then purified to remove dissolved oxides. Finally, an electrical potential is applied between the anode and cathode in an amount sufficient to form substantially pure silicon on the cathode in the form of substantially dense, coherent deposits.

Process to produce lithium-polymer batteries

DOEpatents

MacFadden, K.O.

1998-06-30

A polymer bonded sheet product is described suitable for use as an electrode in a non-aqueous battery system. A porous electrode sheet is impregnated with a solid polymer electrolyte, so as to diffuse into the pores of the electrode. The composite is allowed to cool, and the electrolyte is entrapped in the porous electrode. The sheet products composed have the solid polymer electrolyte composition diffused into the active electrode material by melt-application of the solid polymer electrolyte composition into the porous electrode material sheet. The solid polymer electrolyte is maintained at a temperature that allows for rapid diffusion into the pores of the electrode. The composite electrolyte-electrode sheets are formed on current collectors and can be coated with solid polymer electrolyte prior to battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte coating has low resistance. 1 fig.

Advanced electrolyte/additive for lithium-ion batteries with silicon anode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Shuo; He, Meinan; Su, Chi-Cheung

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. Inmore » this paper, new developments in advanced electrolyte and additive for LIBs with Si anode were systematically reviewed, and perspectives over future research were suggested.« less

High-Efficiency Artificial Photosynthesis Using a Novel Alkaline Membrane Cell

NASA Technical Reports Server (NTRS)

Narayan, Sri; Haines, Brennan; Blosiu, Julian; Marzwell, Neville

2009-01-01

A new cell designed to mimic the photosynthetic processes of plants to convert carbon dioxide into carbonaceous products and oxygen at high efficiency, has an improved configuration using a polymer membrane electrolyte and an alkaline medium. This increases efficiency of the artificial photosynthetic process, achieves high conversion rates, permits the use of inexpensive catalysts, and widens the range of products generated by this type of process. The alkaline membrane electrolyte allows for the continuous generation of sodium formate without the need for any additional separation system. The electrolyte type, pH, electrocatalyst type, and cell voltage were found to have a strong effect on the efficiency of conversion of carbon dioxide to formate. Indium electrodes were found to have higher conversion efficiency compared to lead. Bicarbonate electrolyte offers higher conversion efficiency and higher rates than water solutions saturated with carbon dioxide. pH values between 8 and 9 lead to the maximum values of efficiency. The operating cell voltage of 2.5 V, or higher, ensures conversion of the carbon dioxide to formate, although the hydrogen evolution reaction begins to compete strongly with the formate production reaction at higher cell voltages. Formate is produced at indium and lead electrodes at a conversion efficiency of 48 mg of CO2/kilojoule of energy input. This efficiency is about eight times that of natural photosynthesis in green plants. The electrochemical method of artificial photosynthesis is a promising approach for the conversion, separation and sequestration of carbon dioxide for confined environments as in space habitats, and also for carbon dioxide management in the terrestrial context. The heart of the reactor is a membrane cell fabricated from an alkaline polymer electrolyte membrane and catalyst- coated electrodes. This cell is assembled and held in compression in gold-plated hardware. The cathode side of the cell is supplied with carbon dioxide-saturated water or bicarbonate solution. The anode side of the cell is supplied with sodium hydroxide solution. The solutions are circulated past the electrodes in the electrochemical cell using pumps. A regulated power supply provides the electrical energy required for the reactions. Photovoltaic cells can be used to better mimic the photosynthetic reaction. The current flowing through the electrochemical cell, and the cell voltage, are monitored during experimentation. The products of the electrochemical reduction of carbon dioxide are allowed to accumulate in the cathode reservoir. Samples of the cathode solution are withdrawn for product analysis. Oxygen is generated on the anode side and is allowed to vent out of the reservoir.

Novel ternary molten salt electrolytes for intermediate-temperature sodium/nickel chloride batteries

NASA Astrophysics Data System (ADS)

Li, Guosheng; Lu, Xiaochuan; Coyle, Christopher A.; Kim, Jin Y.; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

2012-12-01

The sodium-nickel chloride (ZEBRA) battery is operated at relatively high temperature (250-350 °C) to achieve adequate electrochemical performance. Reducing the operating temperature in the range of 150200 °C can not only lead to enhanced cycle life by suppressing temperature-related degradations, but also allow the use of lower cost materials for construction. To achieve adequate electrochemical performance at lower operating temperatures, reduction in ohmic losses is required, including the reduced ohmic resistance of β″-alumina solid electrolyte (BASE) and the incorporation of low melting point secondary electrolytes. In present work, planar-type Na/NiCl2 cells with a thin BASE (600 μm) and low melting point secondary electrolyte were evaluated at reduced temperatures. Molten salts used as secondary electrolytes were fabricated by the partial replacement of NaCl in the standard secondary electrolyte (NaAlCl4) with other lower melting point alkali metal salts such as NaBr, LiCl, and LiBr. Electrochemical characterization of these ternary molten salts demonstrated improved ionic conductivity and sufficient electrochemical window at reduced temperatures. Furthermore, Na/NiCl2 cells with 50 mol% NaBr-containing secondary electrolyte exhibited reduced polarizations at 175 °C compared to the cell with the standard NaAlCl4 catholyte. The cells also exhibited stable cycling performance even at 150 °C.

Solid oxide electrochemical cell fabrication process

DOEpatents

Dollard, Walter J.; Folser, George R.; Pal, Uday B.; Singhal, Subhash C.

1992-01-01

A method to form an electrochemical cell (12) is characterized by the steps of thermal spraying stabilized zirconia over a doped lanthanum manganite air electrode tube (14) to provide an electrolyte layer (15), coating conductive particles over the electrolyte, pressurizing the outside of the electrolyte layer, feeding halide vapors of yttrium and zirconium to the outside of the electrolyte layer and feeding a source of oxygen to the inside of the electrolyte layer, heating to cause oxygen reaction with the halide vapors to close electrolyte pores if there are any and to form a metal oxide coating on and between the particles and provide a fuel electrode (16).

Physiological and performance effects of carbohydrate gels consumed prior to the extra-time period of prolonged simulated soccer match-play.

PubMed

Harper, Liam D; Briggs, Marc A; McNamee, Ged; West, Daniel J; Kilduff, Liam P; Stevenson, Emma; Russell, Mark

2016-06-01

The physiological and performance effects of carbohydrate-electrolyte gels consumed before the 30min extra-time period of prolonged soccer-specific exercise were investigated. Randomised, double-blind, crossover. Eight English Premier League academy soccer players performed 120min of soccer-specific exercise on two occasions while consuming fluid-electrolyte beverages before exercise, at half-time and 90min. Carbohydrate-electrolyte (0.7±0.1gkg(-1) BM) or energy-free placebo gels were consumed ∼5min before extra-time. Blood samples were taken before exercise, at half-time and every 15min during exercise. Physical (15-m and 30-m sprint speed, 30-m sprint maintenance and countermovement jump height) and technical (soccer dribbling) performance was assessed throughout each trial. Carbohydrate-electrolyte gels improved dribbling precision (+29±20%) and raised blood glucose concentrations by 0.7±0.8mmoll(-1) during extra-time (both p<0.01). Supplementation did not affect sprint velocities (15m and 30m), 30-m sprint maintenance or dribbling speed as reductions compared to 0-15min values occurred at 105-120min irrespective of trial (all p<0.05). Plasma osmolality and blood sodium concentrations increased post-exercise vs. the opening 15min (p<0.05) but no effect of supplementation existed. Selected markers of physical performance (jump height, 30-m sprint velocity and 30-m repeated sprint maintenance) also reduced by >3% during half-time (all p<0.05). Carbohydrate-electrolyte gel ingestion raised blood glucose concentrations and improved dribbling performance during the extra-time period of simulated soccer match-play. Supplementation did not attenuate reductions in physical performance and hydration status that occurred during extra-time. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effect of fabrication parameters on coating properties of tubular solid oxide fuel cell electrolyte prepared by vacuum slurry coating

NASA Astrophysics Data System (ADS)

Son, Hui-Jeong; Song, Rak-Hyun; Lim, Tak-Hyoung; Lee, Seung-Bok; Kim, Sung-Hyun; Shin, Dong-Ryul

The process of vacuum slurry coating for the fabrication of a dense and thin electrolyte film on a porous anode tube is investigated for application in solid oxide fuel cells. 8 mol% yttria stabilized zirconia is coated on an anode tube by vacuum slurry-coating process as a function of pre-sintering temperature of the anode tube, vacuum pressure, slurry concentration, number of coats, and immersion time. A dense electrolyte layer is formed on the anode tube after final sintering at 1400 °C. With decrease in the pre-sintering temperature of the anode tube, the grain size of the coated electrolyte layer increases and the number of surface pores in the coating layer decreases. This is attributed to a reduced difference in the respective shrinkage of the anode tube and the electrolyte layer. The thickness of the coated electrolyte layer increases with the content of solid powder in the slurry, the number of dip-coats, and the immersion time. Although vacuum pressure has no great influence on the electrolyte thickness, higher vacuum produces a denser coating layer, as confirmed by low gas permeability and a reduced number of defects in the coating layer. A single cell with the vacuum slurry coated electrolyte shows a good performance of 620 mW cm -2 (0.7 V) at 750 °C. These experimental results indicate that the vacuum slurry-coating process is an effective method to fabricate a dense thin film on a porous anode support.

Studies of metals electroprocessing in molten salts

NASA Technical Reports Server (NTRS)

Sadoway, D. R.

1982-01-01

Fluid flow patterns in molten salt electrolytes were observed in order to determine how mass transport affects the morphology of the metal deposit. Studies conducted on the same metal, both in aqueous electrolytes in which coherent solid electrodeposits are produced, as well as in transparent molten salt electrolytes are described. Process variables such as current density and composition of the electrolyte are adjusted to change the morphology of the electrodeposit and, thus, to permit the study of the nature of electrolyte flow in relation to the quality of the electrodeposit.

Electrolyte chemistry control in electrodialysis processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, Thomas D.; Severin, Blaine F.

Methods for controlling electrolyte chemistry in electrodialysis units having an anode and a cathode each in an electrolyte of a selected concentration and a membrane stack disposed therebetween. The membrane stack includes pairs of cationic selective and anionic membranes to segregate increasingly dilute salts streams from concentrated salts stream. Electrolyte chemistry control is via use of at least one of following techniques: a single calcium exclusionary cationic selective membrane at a cathode cell boundary, an exclusionary membrane configured as a hydraulically isolated scavenger cell, a multivalent scavenger co-electrolyte and combinations thereof.

Formation and evolution of anodic TiO2 nanotube embryos

NASA Astrophysics Data System (ADS)

Jin, Rong; Liao, Maoying; Lin, Tong; Zhang, Shaoyu; Shen, Xiaoping; Song, Ye; Zhu, Xufei

2017-06-01

Anodic TiO2 nanotubes (ATNTs) have been widely investigated for decades due to their interesting nanostructures and various applications. However, the formation mechanism of ATNTs still remains unclear. To date, most of researches focus on the tubular structure but neglect the formation process of initial nanotube embryos. Herein, polyethylene glycol (PEG) is added into the traditional electrolyte to moderate the transformation process from compact layer to porous layer. Based on ‘oxygen bubble mould’ and ‘plastic flow model’ theory, the formation and evolution process of nanotube embryo is clarified firstly. Results validate the effect of ‘oxygen bubble mould’ on the formation of nanotube embryo, which has a great effect on regulating the morphology of ATNT arrays. Besides, nanotubes prepared in electrolytes with PEG show shorter tube length with larger diameter than that prepared in traditional electrolytes. The addition of PEG can also effectively avoid the breakdown phenomenon. Highlights Transformation from compact layer into porous layer is observed in PEG electrolyte. The effect of oxygen bubble mould is first demonstrated and observed. The formation process of TiO2 nanotube embryo is described systematically. TiO2 nanotubes prepared in PEG electrolyte show short length and large diameter.

Complexing agent and heavy metal removals from metal plating effluent by electrocoagulation with stainless steel electrodes.

PubMed

Kabdaşli, Işik; Arslan, Tülin; Olmez-Hanci, Tuğba; Arslan-Alaton, Idil; Tünay, Olcay

2009-06-15

In the present study, the treatability of a metal plating wastewater containing complexed metals originating from the nickel and zinc plating process by electrocoagulation using stainless steel electrodes was experimentally investigated. The study focused on the effect of important operation parameters on electrocoagulation process performance in terms of organic complex former, nickel and zinc removals as well as sludge production and specific energy consumption. The results indicated that increasing the applied current density from 2.25 to 9.0 mA/cm(2) appreciably enhanced TOC removal efficiency from 20% to 66%, but a further increase in the applied current density to 56.25 mA/cm(2) did not accelerate TOC removal rates. Electrolyte concentration did not affect the process performance significantly and the highest TOC reduction (66%) accompanied with complete heavy metal removals were achieved at the original chloride content ( approximately 1500 mg Cl/L) of the wastewater sample. Nickel removal performance was adversely affected by the decrease of initial pH from its original value of 6. Optimum working conditions for electrocoagulation of metal plating effluent were established as follows: an applied current density of 9 mA/cm(2), the effluent's original electrolyte concentration and pH of the composite sample. TOC removal rates obtained for all electrocoagulation runs fitted pseudo-first-order kinetics very well (R(2)>92-99).

Recovery of manganese from manganese oxide ores in the EDTA solution

NASA Astrophysics Data System (ADS)

Zhang, Chao; Wang, Shuai; Cao, Zhan-fang; Zhong, Hong

2018-04-01

A new process has been experimentally and theoretically established for the recovery of manganese from manganese oxide ores, mainly including the reductive leaching of manganese by ethylenediaminetetraacetic acid (EDTA), EDTA recovery, and manganese electrolysis. The experimental conditions for this process were investigated. Moderate leaching environment by EDTA with the pH in the range of 5-6 is of benefit to leach manganese from some manganese oxide ores with high-content impurities, such as iron and aluminum. Most of EDTA can be recovered by acidification. A small amount of the residual EDTA in the electrolyte can prevent the generation of anode mud. In addition, trimanganese tetroxide (Mn3O4) can be obtained by the roasting of the EDTA-Mn crystallized product.

Spectrophotometric studies and applications for the determination of Ni2+ in zinc-nickel alloy electrolyte

NASA Astrophysics Data System (ADS)

Qiao, Xiaoping; Li, Helin; Zhao, Wenzhen; Li, Dejun

The absorption properties of zinc-nickel alloy electrolyte were studied by visible spectrophotometer. The results show that the relationship between the absorbance of the zinc-nickel alloy electrolyte and Ni2+ concentration in the electrolyte obeys Beer's law at 660 nm. In addition, other components except Ni2+ in the zinc-nickel alloy electrolyte such as zinc chloride, ammonium chloride, potassium chloride and boric acid have no obvious effect on the absorbance of zinc-nickel alloy electrolyte. Based on these properties, a new method is developed to determine Ni2+ concentration in zinc-nickel alloy electrolyte. Comparing with other methods, this method is simple, direct and accurate. Moreover, the whole testing process does not consume any reagent and dilution, and after testing, the electrolyte samples can be reused without any pollution to the environment.

Adsorptive behaviour of mercury on algal biomass: competition with divalent cations and organic compounds.

PubMed

Carro, Leticia; Barriada, José L; Herrero, Roberto; Sastre de Vicente, Manuel E

2011-08-15

Biosorption processes constitute an effective technique for mercury elimination. Sorption properties of native and acid-treated Sargassum muticum have been studied. Effect of pH, initial mercury concentration and contact time studies provided fundamental information about the sorption process. This information was used as the reference values to analyse mercury sorption under competition conditions. Saline effect has shown little influence in sorption, when only electrostatic modifications took place upon salt addition. On the contrary, if mercury speciation dramatically changed owing to the addition of an electrolyte, such as in the case of chloride salt, very large modifications in mercury sorption were observed. Competition with other divalent cations or organic compounds has shown little or none effect on mercury, indicating that a different mechanism is taking place during the removal of these pollutants. Finally, continuous flow experiments have clearly shown that a reduction process is also taking place during mercury removal. This fact is not obvious to elucidate under batch sorption experiments. Scanning Electron Microscopy analysis of the surface of the materials show deposits of mercury(I) and metallic mercury which is indicative of the reduction process proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

Sequential reductive and oxidative biodegradation of chloroethenes stimulated in a coupled bioelectro-process.

PubMed

Lohner, Svenja T; Becker, Dirk; Mangold, Klaus-Michael; Tiehm, Andreas

2011-08-01

This article for the first time demonstrates successful application of electrochemical processes to stimulate sequential reductive/oxidative microbial degradation of perchloroethene (PCE) in mineral medium and in contaminated groundwater. In a flow-through column system, hydrogen generation at the cathode supported reductive dechlorination of PCE to cis-dichloroethene (cDCE), vinyl chloride (VC), and ethene (ETH). Electrolytically generated oxygen at the anode allowed subsequent oxidative degradation of the lower chlorinated metabolites. Aerobic cometabolic degradation of cDCE proved to be the bottleneck for complete metabolite elimination. Total removal of chloroethenes was demonstrated for a PCE load of approximately 1.5 μmol/d. In mineral medium, long-term operation with stainless steel electrodes was demonstrated for more than 300 days. In contaminated groundwater, corrosion of the stainless steel anode occurred, whereas DSA (dimensionally stable anodes) proved to be stable. Precipitation of calcareous deposits was observed at the cathode, resulting in a higher voltage demand and reduced dechlorination activity. With DSA and groundwater from a contaminated site, complete degradation of chloroethenes in groundwater was obtained for two months thus demonstrating the feasibility of the sequential bioelectro-approach for field application.

Study of the electrochemical oxidation and reduction of C.I. Reactive Orange 4 in sodium sulphate alkaline solutions.

PubMed

del Río, A I; Molina, J; Bonastre, J; Cases, F

2009-12-15

Synthetic solutions of hydrolysed C.I. Reactive Orange 4, a monoazo textile dye commercially named Procion Orange MX-2R (PMX2R) and colour index number C.I. 18260, was exposed to electrochemical treatment under galvanostatic conditions and Na2SO4 as electrolyte. The influence of the electrochemical process as well as the applied current density was evaluated. Ti/SnO2-Sb-Pt and stainless steel electrodes were used as anode and cathode, respectively, and the intermediates generated on the cathode during electrochemical reduction were investigated. Aliquots of the solutions treated were analysed by UV-visible and FTIR-ATR spectroscopy confirming the presence of aromatic structures in solution when an electro-reduction was carried out. Electro-oxidation degraded both the azo group and aromatic structures. HPLC measures revealed that all processes followed pseudo-first order kinetics and decolourisation rates showed a considerable dependency on the applied current density. CV experiments and XPS analyses were carried out to study the behaviour of both PMX2R and intermediates and to analyse the state of the cathode after the electrochemical reduction, respectively. It was observed the presence of a main intermediate in solution after an electrochemical reduction whose chemical structure is similar to 2-amino-1,5-naphthalenedisulphonic acid. Moreover, the analysis of the cathode surface after electrochemical reduction reveals the presence of a coating layer with organic nature.

Identifying compatibility of lithium salts with LiFePO4 cathode using a symmetric cell

NASA Astrophysics Data System (ADS)

Tong, Bo; Wang, Jiawei; Liu, Zhenjie; Ma, Lipo; Zhou, Zhibin; Peng, Zhangquan

2018-04-01

The electrochemical performance of lithium-ion batteries is dominated by the interphase electrochemistry between the electrolyte and electrode materials. A multitude of efforts have been dedicated to the solid electrolyte interphase (SEI) formed on the anode. However, the interphase on the cathode, namely the cathode electrolyte interphase (CEI), is left aside, partially due to the fact that it is hard to single out the CEI considering the complicated anode-cathode inter-talk. Herein, a partially delithiated lithium iron phosphate (Li0.25FePO4) electrode is used as the anode. Owing to a high voltage plateau (≈3.45 V vs. Li/Li+), negligible reduction reactions of electrolyte occur on the L0.25FePO4 anode. Therefore, the CEI can be investigated exclusively. Using a LiFePO4|Li0.25FePO4 symmetric cell configuration, we scrutinize the compatibility of the electrolytes containing a wide spectrum of lithium salts, Li[(FSO2)(Cm F2m+1SO2)N] (m = 0, 1, 2, 4), with the LiFePO4, in both cycling and calendar tests. It is found that the Li[(FSO2)(n-C4F9SO2)N] (LiFNFSI)-based electrolyte exhibits the highest compatibility with LiFePO4.

Highly Selective TiN-Supported Highly Dispersed Pt Catalyst: Ultra Active toward Hydrogen Oxidation and Inactive toward Oxygen Reduction.

PubMed

Luo, Junming; Tang, Haibo; Tian, Xinlong; Hou, Sanying; Li, Xiuhua; Du, Li; Liao, Shijun

2018-01-31

The severe dissolution of the cathode catalyst, caused by an undesired oxygen reduction reaction at the anode during startup and shutdown, is a fatal challenge to practical applications of polymer electrolyte membrane fuel cells. To address this important issue, according to the distinct structure-sensitivity between the σ-type bond in H 2 and the π-type bond in O 2 , we design a HD-Pt/TiN material by highly dispersing Pt on the TiN surface to inhibit the unwanted oxygen reduction reaction. The highly dispersed Pt/TiN catalyst exhibits excellent selectivity toward hydrogen oxidation and oxygen reduction reactions. With a Pt loading of 0.88 wt %, our catalyst shows excellent hydrogen oxidation reaction activity, close to that of commercial 20 wt % Pt/C catalyst, and much lower oxygen reduction reaction activity than the commercial 20 wt % Pt/C catalyst. The lack of well-ordered Pt facets is responsible for the excellent selectivity of the HD-Pt/TiN materials toward hydrogen oxidation and oxygen reduction reactions. Our work provides a new and cost-effective solution to design selective catalysts toward hydrogen oxidation and oxygen reduction reactions, making the strategy of using oxygen-tolerant anode catalyst to improve the stability of polymer electrolyte membrane fuel cells during startup and shutdown more affordable and practical.

Chemical modification of electrolytes for lithium batteries

NASA Astrophysics Data System (ADS)

Afanas'ev, Vladimir N.; Grechin, Aleksandr G.

2002-09-01

Modern approaches to modifying chemically electrolytes for lithium batteries are analysed with the aim of optimising the charge-transfer processes in liquid-phase and solid (polymeric) media. The main regularities of transport properties of lithium electrolyte solutions containing complex (encapsulated) ions in aprotic solvents and polymers are discussed. The prospects for the development of electrolytic solvosystems with the chain (ionotropic) mechanism of conduction with respect to lithium ions are outlined. The bibliography includes 126 references.

Electrochemistry of poly(3,4-ethylenedioxythiophene)-polyaniline/ Prussian blue electrochromic devices containing an ionic liquid based gel electrolyte film.

PubMed

Deepa, Melepurath; Awadhia, Arvind; Bhandari, Shweta

2009-07-21

Electrochromic devices based on poly(3,4-ethylenedioxythiophene) (PEDOT) as the cathodic coloring electrode and polyaniline (PANI) or Prussian blue (PB) as the counter electrode containing a highly conductive, self-supporting, distensible and transparent polymer-gel electrolyte film encapsulating an ionic liquid, 1-butyl-1-methylpyrrolidiniumbis-(trifluoromethylsulfonyl)imide, have been fabricated. Polarization, charge transfer and diffusion processes control the electrochemistry of the functional electrodes during coloration and bleaching and these phenomena differ when PEDOT and PANI/PB were employed alternately as working electrodes. While the electrochemical impedance response shows good similitude for PEDOT and PANI electrodes, the responses of PEDOT and PB were significantly different in the PEDOT-PB device, especially during reduction of PB, wherein the overall amplitude of the impedance response is enormous. Large values of the coloration efficiency maxima of 281 cm2 C(-1) (lambda = 583 nm) and 274 cm2 C(-1) (lambda = 602 nm), achieved at -1.0 and -1.5 V for the PEDOT PANI and PEDOT-PB devices have been correlated to the particularly low magnitude of charge transfer resistance and high polarization capacitance operative at the PEDOT ionic liquid based electrolyte interface at these dc potentials, thus allowing facile ion-transport and consequently resulting in enhanced absorption modulation. Moderately fast switching kinetics and the ability of these devices to sustain about 2500 cycles of clear-to-dark and dark-to-clear without incurring major losses in the optical contrast, along with the ease of construction of these cells in terms of high scalability and reproducibility of the synthetic procedure for fabrication of the electrochromic films and the ionic liquid based gel electrolyte film, are indicators of the promise these devices hold for practical applications like electrochromic windows and displays.

Use of Thermodynamic Modeling for Selection of Electrolyte for Electrorefining of Magnesium from Aluminum Alloy Melts

NASA Astrophysics Data System (ADS)

Gesing, Adam J.; Das, Subodh K.

2017-02-01

With United States Department of Energy Advanced Research Project Agency funding, experimental proof-of-concept was demonstrated for RE-12TM electrorefining process of extraction of desired amount of Mg from recycled scrap secondary Al molten alloys. The key enabling technology for this process was the selection of the suitable electrolyte composition and operating temperature. The selection was made using the FactSage thermodynamic modeling software and the light metal, molten salt, and oxide thermodynamic databases. Modeling allowed prediction of the chemical equilibria, impurity contents in both anode and cathode products, and in the electrolyte. FactSage also provided data on the physical properties of the electrolyte and the molten metal phases including electrical conductivity and density of the molten phases. Further modeling permitted selection of electrode and cell construction materials chemically compatible with the combination of molten metals and the electrolyte.

Oxygen reduction reaction catalyzed by nickel complexes based on thiophosphorylated calix[4]resorcinols and immobilized in the membrane electrode assembly of fuel cells.

PubMed

Kadirov, M K; Knyazeva, I R; Nizameev, I R; Safiullin, R A; Matveeva, V I; Kholin, K V; Khrizanforova, V V; Ismaev, T I; Burilov, A R; Budnikova, Yu H; Sinyashin, O G

2016-10-18

The catalytic activity of the nickel complexes of thiophosphorylated calix[4]resorcinols for oxygen reduction in a polymer electrolyte membrane fuel cell (PEMFC) has been studied. The conformation of the macrocyclic ligand determines the morphology and catalytic properties of the resulting organometallic species.

Toward a Molecular Understanding of Energetics in Li–S Batteries Using Nonaqueous Electrolytes: A High-Level Quantum Chemical Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Assary, Rajeev S.; Curtiss, Larry A.; Moore, Jeffrey S.

2014-06-05

The Li-S battery (secondary cell or redox flow) technology is a promising future alternative to the present lithium intercalation-based energy storage and, therefore, a molecular level understanding of the chemical processes and properties such as stability of intermediates, reactivity of polysulfides and reactivity towards the non-aqueous electrolytes in the Li-S batteries is of great interest. In this paper, quantum chemical methods (G4MP2, MP2, and B3LYP) were utilized to compute reduction potentials of lithium polysulfides and polysulfide molecular clusters, energetics of disproportionation and association reactions of likely intermediates, and their reactions with ether-based electrolytes. Based on the computed reaction energetics inmore » solution, a probable mechanism during the discharge process for polysulfide anions and lithium polysulfides in solution is proposed and likely intermediates such as S42-,S32-, S22-, and S31- radical were identified. Additionally, the stability and reactivity of propylene carbonate and tetraglyme solvent molecules were assessed against the above-mentioned intermediates and other reactive species by computing the reaction energetics required to initiate the solvent decomposition reactions in solution. Calculations suggest that the propylene carbonate molecule is unstable against the polysulfide anions such as S22-, S32-, and S42- (ΔH† < 0.8 eV) and highly reactive towards Li2S2 and Li2S3. Even though the tetraglyme solvent molecule exhibits increased stability towards polysulfide anions compared to propylene carbonate, this molecule too is vulnerable to nucleophilic attack from Li2S2 and Li2S3 species in solutions. Hence, a long- term stability of the ether molecules is unlikely if high concentration of these reactive intermediates present in the Li-S energy storage systems.« less

Nondestructive cell evaluation techniques in SOFC stack manufacturing

NASA Astrophysics Data System (ADS)

Wunderlich, C.

2016-04-01

Independent from the specifics of the application, a cost efficient manufacturing of solid oxide fuel cells (SOFC), its electrolyte membranes and other stack components, leading to reliable long-life stacks is the key for the commercial viability of this fuel cell technology. Tensile and shear stresses are most critical for ceramic components and especially for thin electrolyte membranes as used in SOFC cells. Although stack developers try to reduce tensile stresses acting on the electrolyte by either matching CTE of interconnects and electrolytes or by putting SOFC cells under some pressure - at least during transient operation of SOFC stacks ceramic cells will experience some tensile stresses. Electrolytes are required to have a high Weibull characteristic fracture strength. Practical experiences in stack manufacturing have shown that statistical fracture strength data generated by tests of electrolyte samples give limited information on electrolyte or cell quality. In addition, the cutting process of SOFC electrolytes has a major influence on crack initiation. Typically, any single crack in one the 30 to 80 cells in series connection will lead to a premature stack failure drastically reducing stack service life. Thus, for statistical reasons only 100% defect free SOFC cells must be assembled in stacks. This underlines the need for an automated inspection. So far, only manual processes of visual or mechanical electrolyte inspection are established. Fraunhofer IKTS has qualified the method of optical coherence tomography for an automated high throughput inspection. Alternatives like laser speckle photometry and acoustical methods are still under investigation.

Tin, Bismuth, and Tin–Bismuth Alloy Electrodeposition from Chlorometalate Salts in Deep Eutectic Solvents

PubMed Central

Vieira, Luciana; Burt, Jennifer; Richardson, Peter W.; Schloffer, Daniel; Fuchs, David; Moser, Alwin; Bartlett, Philip N.; Reid, Gillian

2017-01-01

Abstract The electrodeposition of tin, bismuth, and tin–bismuth alloys from SnII and BiIII chlorometalate salts in the choline chloride/ethylene glycol (1:2 molar ratio) deep eutectic solvent was studied on glassy carbon and gold by cyclic voltammetry, rotating disc voltammetry, and chronoamperometry. The SnII‐containing electrolyte showed one voltammetric redox process corresponding to SnII/Sn0. The diffusion coefficient of [SnCl3]−, detected as the dominating species by Raman spectroscopy, was determined from Levich and Cottrell analyses. The BiIII‐containing electrolyte showed two voltammetric reduction processes, both attributed to BiIII/Bi0. Dimensionless current/time transients revealed that the electrodeposition of both Sn and Bi on glassy carbon proceeded by 3D‐progressive nucleation at a low overpotential and changed to instantaneous at higher overpotentials. The nucleation rate of Bi on glassy carbon was considerably smaller than that of Sn. Elemental Sn and Bi were electrodeposited on Au‐coated glass slides from their respective salt solutions, as were Sn–Bi alloys from a 2:1 SnII/BiIII solution. The biphasic Sn–Bi alloys changed from a Bi‐rich composition to a Sn‐rich composition by making the deposition potential more negative. PMID:28638772

Reclaiming the spent alkaline zinc manganese dioxide batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Ya; Cui, Yan; Zuo, Xiaoxi

2014-10-15

Highlights: • The spent Zn–Mn batteries collected from manufacturers is the target waste. • A facile reclaiming process is presented. • The zinc is reclaimed to valuable electrolytic zinc by electrodepositing method. • The manganese elements are to produce valuable LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} battery material. • The reclamation process features environmental friendliness and saving resource. - Abstract: A process for reclaiming the materials in spent alkaline zinc manganese dioxide (Zn–Mn) batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} materials is presented. After dismantling battery cans, the iron cans, covers, electric rods, organicmore » separator, label, sealing materials, and electrolyte are separated through the washing, magnetic separation, filtrating, and sieving operations. Then, the powder residues react with H{sub 2}SO{sub 4} (2 mol L{sup −1}) solution to dissolve zinc under a liquid/solid ratio of 3:1 at room temperature, and subsequently, the electrolytic Zn with purity of ⩾99.8% is recovered in an electrolytic cell with a cathode efficiency of ⩾85% under the conditions of 37–40 °C and 300 A m{sup −2}. The most of MnO{sub 2} and a small quantity of electrolytic MnO{sub 2} are recovered from the filtration residue and the electrodeposit on the anode of electrolytic cell, respectively. The recovered manganese oxides are used to synthesize LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} material of lithium-ion battery. The as-synthesized LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} discharges 118.3 mAh g{sup −1} capacity and 4.7 V voltage plateau, which is comparable to the sample synthesized using commercial electrolytic MnO{sub 2}. This process can recover the substances in the spent Zn–Mn batteries and innocuously treat the wastewaters, indicating that it is environmentally acceptable and applicable.« less

Globally sustainable manganese metal production and use.

PubMed

Hagelstein, Karen

2009-09-01

The "cradle to grave" concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices-such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also reduces the quantity of solid wastes generated during processing. Secondary aluminum facilities have reported hazardous waste generation management issues due to baghouse dusts from rotary furnaces processing selenium contaminated manganese alloys. Environmental impacts resulting from industry are represented by emission inventories of chemical releases to the air, water, and soil. The U.S. metals industry releases reported to EPA Toxic Release Inventory indicate the primary metals industry is the major source of metal air toxic emissions, exceeding electric utility air toxic emissions. The nonferrous metals industry is reported to be the Organization for Economic Co-operation and Development (OECD) most intensive airborne and land pollution source of bioaccumulative metals. However, total waste emissions from industries in the OECD countries have declined due to improving energy consumption. Emission registers and access are improving around the world. However, environmental databases for metal particulates have low confidence ratings since the majority of air toxic emissions are not reported, not monitored, or are estimated based on worst-case emission factors. Environmental assessments including biological monitoring are necessary to validate mandated particulate metal emission reductions and control technologies during metal processing.

Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays

PubMed Central

2012-01-01

Nanochannel arrays were fabricated by the self-organized multi-electrolyte-step anodic aluminum oxide [AAO] method in this study. The anodization conditions used in the multi-electrolyte-step AAO method included a phosphoric acid solution as the electrolyte and an applied high voltage. There was a change in the phosphoric acid by the oxalic acid solution as the electrolyte and the applied low voltage. This method was used to produce self-organized nanochannel arrays with good regularity and circularity, meaning less power loss and processing time than with the multi-step AAO method. PMID:22333268

Electrolytes for Use in High Energy Lithium-Ion Batteries with Wide Operating Temperature Range

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

2011-01-01

Objectives of this work are: (1) Develop advanced Li -ion electrolytes that enable cell operation over a wide temperature range (i.e., -30 to +60C). (2) Improve the high temperature stability and lifetime characteristics of wide operating temperature electrolytes. (3) Improve the high voltage stability of these candidate electrolytes systems to enable operation up to 5V with high specific energy cathode materials. (4) Define the performance limitations at low and high temperature extremes, as well as, life limiting processes. (5) Demonstrate the performance of advanced electrolytes in large capacity prototype cells.

Structure-Property Relationships of Organic Electrolytes and Their Effects on Li/S Battery Performance.

PubMed

Kaiser, Mohammad Rejaul; Chou, Shulei; Liu, Hua-Kun; Dou, Shi-Xue; Wang, Chunsheng; Wang, Jiazhao

2017-12-01

Electrolytes, which are a key component in electrochemical devices, transport ions between the sulfur/carbon composite cathode and the lithium anode in lithium-sulfur batteries (LSBs). The performance of a LSB mostly depends on the electrolyte due to the dissolution of polysulfides into the electrolyte, along with the formation of a solid-electrolyte interphase. The selection of the electrolyte and its functionality during charging and discharging is intricate and involves multiple reactions and processes. The selection of the proper electrolyte, including solvents and salts, for LSBs strongly depends on its physical and chemical properties, which is heavily controlled by its molecular structure. In this review, the fundamental properties of organic electrolytes for LSBs are presented, and an attempt is made to determine the relationship between the molecular structure and the properties of common organic electrolytes, along with their effects on the LSB performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells

PubMed Central

Shui, Jianglan; Wang, Min; Du, Feng; Dai, Liming

2015-01-01

The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells. PMID:26601132

N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells.

PubMed

Shui, Jianglan; Wang, Min; Du, Feng; Dai, Liming

2015-02-01

The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells.

Formation of TiO2 nanostructure by plasma electrolytic oxidation for Cr(VI) reduction

NASA Astrophysics Data System (ADS)

Torres, D. A.; Gordillo-Delgado, F.; Plazas-Saldaña, J.

2017-01-01

Plasma electrolytic oxidation (PEO) is an environmentally friendly technique that allows the growth of ceramic coatings without organic solvents and non-toxic residues. This method was applied to ASME SB-265 titanium (Ti) plates (2×2×0.1cm) using voltage pulses from a switching power supply (340V) for 10 minutes at frequency of 1000Hz changing duty cycle at 10, 60 and 90% and the electrolytes were Na3PO4 and NaOH. The treated sheets surfaces were analysed by X-ray diffraction and scanning electron microscopy. According to the diffractograms, the duty cycle increase produces amorphous TiO2 coating on Ti sheets and the thickness increases. After sintering at 900°C during 1 hour, the 10% duty cycle generated a combination of anatase and rutile phases at the sample surface with weight percentages of 13.3 and 86.6% and particle sizes of 32.461±0.009nm and 141.14±0.03 nm, respectively. With this sample, the total reduction of hexavalent chromium was reached at 50 minutes for 1ppm solution. This photocatalytic activity was measured following the colorimetric method ASTM-3500-Cr B.

Sieving of electrolytes at capillary wall of cat skeletal muscle by osmotic water flow.

PubMed

Watson, P D

1993-12-01

To test the hypothesis that a significant proportion of transcapillary water flow occurs through solute-restricting channels, we investigated the effects of transcapillary water movement on plasma electrolytes in isolated perfused cat skeletal muscle. The lower hindlimbs of anesthetized cats were perfused with a plasma-albumin solution and were weighed to determine transcapillary water movement. Osmolality was increased 60-70 mosmol/kgH2O with sucrose, creating water fluxes of 8-10 ml.min-1.100 g-1, and the changes in the venous concentrations of sodium, potassium, and chloride were determined. The ion concentrations were all reduced by 6-7% with no significant difference between them. The amount of reduction was quantitatively explained by the flow of ion-free water from the interstitial space into plasma and the diffusion of electrolyte in the same direction. These findings support the hypothesis that important water-only transcapillary channels exist in mammalian skeletal muscle. The observations may also explain some of the electrolyte changes seen in intense exercise.

Optical and Electrical Characteristics of Silver Ion Conducting Nanocomposite Solid Polymer Electrolytes Based on Chitosan

NASA Astrophysics Data System (ADS)

Aziz, Shujahadeen B.; Rasheed, Mariwan A.; Abidin, Zul H. Z.

2017-10-01

Optical and electrical properties of nanocomposite solid polymer electrolytes based on chitosan have been investigated. Incorporation of alumina nanoparticles into the chitosan:silver triflate (AgTf) system broadened the surface plasmon resonance peaks of the silver nanoparticles and shifted the absorption edge to lower photon energy. A clear decrease of the optical bandgap in nanocomposite samples containing alumina nanoparticles was observed. The variation of the direct-current (DC) conductivity and dielectric constant followed the same trend with alumina concentration. The DC conductivity increased by two orders of magnitude, which can be attributed to hindrance of silver ion reduction. Transmission electron microscopy was used to interpret the space-charge and blocking effects of alumina nanoparticles on the DC conductivity and dielectric constant. The ion conduction mechanism was interpreted based on the dependences of the electrical and dielectric parameters. The dependence of the DC conductivity on the dielectric constant is explained empirically. Relaxation processes associated with conductivity and viscoelasticity were distinguished based on the incomplete semicircular arcs in plots of the real and imaginary parts of the electric modulus.

A novel method for identification of lithium-ion battery equivalent circuit model parameters considering electrochemical properties

NASA Astrophysics Data System (ADS)

Zhang, Xi; Lu, Jinling; Yuan, Shifei; Yang, Jun; Zhou, Xuan

2017-03-01

This paper proposes a novel parameter identification method for the lithium-ion (Li-ion) battery equivalent circuit model (ECM) considering the electrochemical properties. An improved pseudo two-dimension (P2D) model is established on basis of partial differential equations (PDEs), since the electrolyte potential is simplified from the nonlinear to linear expression while terminal voltage can be divided into the electrolyte potential, open circuit voltage (OCV), overpotential of electrodes, internal resistance drop, and so on. The model order reduction process is implemented by the simplification of the PDEs using the Laplace transform, inverse Laplace transform, Pade approximation, etc. A unified second order transfer function between cell voltage and current is obtained for the comparability with that of ECM. The final objective is to obtain the relationship between the ECM resistances/capacitances and electrochemical parameters such that in various conditions, ECM precision could be improved regarding integration of battery interior properties for further applications, e.g., SOC estimation. Finally simulation and experimental results prove the correctness and validity of the proposed methodology.

The mechanism of Li2S activation in lithium-sulfur batteries: Can we avoid the polysulfide formation?

NASA Astrophysics Data System (ADS)

Vizintin, Alen; Chabanne, Laurent; Tchernychova, Elena; Arčon, Iztok; Stievano, Lorenzo; Aquilanti, Giuliana; Antonietti, Markus; Fellinger, Tim-Patrick; Dominko, Robert

2017-03-01

Electrochemical reactions in the Lisbnd S batteries are considered as a multistep reaction process with at least 2-3 equilibrium states. Here we report a possibility of having a conversion of Li2S into sulfur without detectible formation of polysulfides. That was confirmed by using a novel material system consisting of carbon coated Li2S particles prepared by carbothermal reduction of Li2SO4. Two independent in operando measurements showed direct oxidation of Li2S into sulfur for this system, with almost negligible formation of polysulfides at potentials above 2.5 V vs. Li/Li+. Our results link the diversity of first charge profiles in the literature to the Li2S oxidation mechanism and show the importance of ionic wiring within the material. Furthermore, we demonstrate that the Li2S oxidation mechanism depends on the relative amount of soluble sulfur in the electrolyte. By controlling the type and the amount of electrolyte within the encapsulating carbon shell, it is thereby possible to control the reaction mechanism of Li2S activation.

Issues on the production and electrochemical separation of oxygen from carbon dioxide

NASA Technical Reports Server (NTRS)

Kaloupis, P.; Sridhar, K. R.

1991-01-01

There is considerable interest in in-situ propellant manufacturing on the moon and Mars. One of the concepts of oxygen production that is being actively pursued is the processing of atmospheric carbon dioxide on Mars to produce oxygen by means of thermal decomposition and electrochemical separation. The key component of such a production facility is the electrochemical separation cell that filters out the oxygen from the gas mixture of carbon dioxide, carbon monoxide, and oxygen. Efficient design of the separation cell and the selection of electrolyte and electrode materials of superior performance for the cell would translate to significant reduction in the power requirement and the mass of the production facility. The objective is to develop the technology required to produce the cells in-house and test various electrolyte and electrode materials systematically until the optimal combination is found. An effective technique was developed for the fabrication of disk shaped cells. Zirconia and Ceria cells were made in-house. Complete modules of the electrochemical cell and housings were designed, fabricated, and tested.

Plutonium recovery from spent reactor fuel by uranium displacement

DOEpatents

Ackerman, John P.

1992-01-01

A process for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

Review on modeling of the anode solid electrolyte interphase (SEI) for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Wang, Aiping; Kadam, Sanket; Li, Hong; Shi, Siqi; Qi, Yue

2018-03-01

A passivation layer called the solid electrolyte interphase (SEI) is formed on electrode surfaces from decomposition products of electrolytes. The SEI allows Li+ transport and blocks electrons in order to prevent further electrolyte decomposition and ensure continued electrochemical reactions. The formation and growth mechanism of the nanometer thick SEI films are yet to be completely understood owing to their complex structure and lack of reliable in situ experimental techniques. Significant advances in computational methods have made it possible to predictively model the fundamentals of SEI. This review aims to give an overview of state-of-the-art modeling progress in the investigation of SEI films on the anodes, ranging from electronic structure calculations to mesoscale modeling, covering the thermodynamics and kinetics of electrolyte reduction reactions, SEI formation, modification through electrolyte design, correlation of SEI properties with battery performance, and the artificial SEI design. Multi-scale simulations have been summarized and compared with each other as well as with experiments. Computational details of the fundamental properties of SEI, such as electron tunneling, Li-ion transport, chemical/mechanical stability of the bulk SEI and electrode/(SEI/) electrolyte interfaces have been discussed. This review shows the potential of computational approaches in the deconvolution of SEI properties and design of artificial SEI. We believe that computational modeling can be integrated with experiments to complement each other and lead to a better understanding of the complex SEI for the development of a highly efficient battery in the future.

Dielectric relaxations and conduction mechanisms in polyether-clay composite polymer electrolytes under high carbon dioxide pressure.

PubMed

Kitajima, Shunsuke; Bertasi, Federico; Vezzù, Keti; Negro, Enrico; Tominaga, Yoichi; Di Noto, Vito

2013-10-21

The composite material P(EO/EM)-Sa consisting of synthetic saponite (Sa) dispersed in poly[ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidyl ether] (P(EO/EM)) is studied by "in situ" measurements using broadband electrical spectroscopy (BES) under pressurized CO2 to characterize the dynamic behavior of conductivity and the dielectric relaxations of the ion host polymer matrix. It is revealed that there are three dielectric relaxation processes associated with: (I) the dipolar motions in the short oxyethylene side chains of P(EO/EM) (β); and (II) the segmental motion of the main chains comprising the polyether components (αfast, αslow). αslow is attributed to the slow α-relaxation of P(EO/EM) macromolecules, which is hindered by the strong coordination interactions with the ions. Two conduction processes are observed, σDC and σID, which are attributed, respectively, to the bulk conductivity and the interdomain conductivity. The temperature dependence of conductivity and relaxation processes reveals that αfast and αslow are strongly correlated with σDC and σID. The "in situ" BES measurements under pressurized CO2 indicate a fast decrease in σDC at the initial CO2 treatment time resulting from the decrease in the concentration of polyether-M(n+) complexes, which is driven by the CO2 permeation. The relaxation frequency (fR) of αslow at the initial CO2 treatment time increases and shows a steep rise with time with the same behavior of the αfast mode. It is demonstrated that the interactions between polyether chains of P(EO/EM) and cations in the polymer electrolyte layers embedded in Sa are probably weakened by the low permittivity of CO2 (ε = 1.08). Thus, the formation of ion pairs in the polymer electrolyte domains of P(EO/EM)-Sa occurs, with a corresponding reduction in the concentration of ion carriers.

Microscopic dynamics research on the "mature" process of dye-sensitized solar cells after injection of highly concentrated electrolyte.

PubMed

Liang, Zhongguan; Liu, Weiqing; Chen, Jun; Hu, Linhua; Dai, Songyuan

2015-01-21

After injection of electrolyte, the internal three-dimensional solid-liquid penetration system of dye-sensitized solar cells (DSCs) can take a period of time to reach "mature" state. This paper studies the changes of microscopic processes of DSCs including TiO2 energy-level movement, localized state distribution, charge accumulation, electron transport, and recombination dynamics, from the beginning of electrolyte injection to the time of reached mature state. The results show that the microscopic dynamics process of DSCs exhibited a time-dependent behavior and achieved maturity ∼12 h after injecting the electrolyte into DSCs. Within 0-12 h, several results were observed: (1) the conduction band edge of TiO2 moved slightly toward negative potential direction; (2) the localized states in the band gap of TiO2 was reduced according to the same distribution law; (3) the transport resistance in TiO2 film increased, and electron transport time was prolonged as the time of maturity went on, which indicated that the electron transport process is impeded gradually; (4) the recombination resistance at the TiO2/electrolyte (EL) interface increases, and electron lifetime gradually extends, therefore, the recombination process is continuously suppressed. Furthermore, results suggest that the parameters of EL/Pt-transparent conductive oxide (TCO) interface including the interfacial capacitance, electron-transfer resistance, and transfer time constant would change with time of maturity, indicating that the EL/Pt-TCO interface is a potential factor affecting the mature process of DSCs.

Combinations of laxatives and green banana biomass on the treatment of functional constipation in children and adolescents: a randomized study.

PubMed

Cassettari, Vanessa Mello Granado; Machado, Nilton Carlos; Lourenção, Pedro Luiz Toledo de Arruda; Carvalho, Marry Assis; Ortolan, Erika Veruska Paiva

2018-01-05

Evaluate the effect of combinations of green banana biomass and laxatives in children and adolescents with chronic constipation. This was a randomized study of 80 children and adolescents with functional constipation according to the Rome IV Criteria, who were divided into five groups: (1) green banana biomass alone; (2) green banana biomass plus PEG 3350 with electrolytes; (3) green banana biomass plus sodium picosulfate; (4) PEG 3350 with electrolytes alone; and (5) sodium picosulfate alone. Primary outcome measure was the reduction of the proportion of patients with Bristol Stool Form Scale ratings 1 or 2. Secondary outcome measures were: increase of the proportion of >3 bowel movements/week and reduction of the proportion of fecal incontinence, straining on defecation, painful defecation, blood in stool, abdominal pain, and decreased laxative doses. On consumption of green banana biomass alone, a statistically significant reduction was observed in the proportion of children with Bristol Stool Form Scale rating 1 or 2, straining on defecation, painful defecation, and abdominal pain. Conversely, no reduction was observed in fecal incontinence episodes/week, blood in stool, and no increase was observed in the proportion of children with >3 bowel movements/week. The percentage of children who required decreased laxative dose was high when green banana biomass was associated with sodium picosulfate (87%), and PEG 3350 with electrolytes (63%). Green banana biomass alone and associated with laxatives was well tolerated, and no adverse effects were reported. Green banana biomass is advantageous as an adjunct therapy on functional constipation, mainly for reducing doses of laxatives. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Protected Lithium-Metal Anodes in Batteries: From Liquid to Solid.

PubMed

Yang, Chunpeng; Fu, Kun; Zhang, Ying; Hitz, Emily; Hu, Liangbing

2017-09-01

High-energy lithium-metal batteries are among the most promising candidates for next-generation energy storage systems. With a high specific capacity and a low reduction potential, the Li-metal anode has attracted extensive interest for decades. Dendritic Li formation, uncontrolled interfacial reactions, and huge volume effect are major hurdles to the commercial application of Li-metal anodes. Recent studies have shown that the performance and safety of Li-metal anodes can be significantly improved via organic electrolyte modification, Li-metal interface protection, Li-electrode framework design, separator coating, and so on. Superior to the liquid electrolytes, solid-state electrolytes are considered able to inhibit problematic Li dendrites and build safe solid Li-metal batteries. Inspired by the bright prospects of solid Li-metal batteries, increasing efforts have been devoted to overcoming the obstacles of solid Li-metal batteries, such as low ionic conductivity of the electrolyte and Li-electrolyte interfacial problems. Here, the approaches to protect Li-metal anodes from liquid batteries to solid-state batteries are outlined and analyzed in detail. Perspectives regarding the strategies for developing Li-metal anodes are discussed to facilitate the practical application of Li-metal batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improvements to Zirconia Thick-Film Oxygen Sensors

NASA Astrophysics Data System (ADS)

Maskell, William C.; Brett, Daniel J. L.; Brandon, Nigel P.

2013-06-01

Thick-film zirconia gas sensors are normally screen-printed onto a planar substrate. A sandwich of electrode-electrolyte-electrode is fired at a temperature sufficient to instigate sintering of the zirconia electrolyte. The resulting porous zirconia film acts as both the electrolyte and as the diffusion barrier through which oxygen diffuses. The high sintering temperature results in de-activation of the electrodes so that sensors must be operated at around 800 °C for measurements in the percentage range of oxygen concentration. This work shows that the use of cobalt oxide as a sintering aid allows reduction of the sensor operating temperature by 100-200 °C with clear benefits. Furthermore, an interesting and new technique is presented for the investigation of the influence of dopants and of the through-porosity of ionically-conducting materials.

Automatic electrochemical ambient air monitor for chloride and chlorine

DOEpatents

Mueller, Theodore R.

1976-07-13

An electrochemical monitoring system has been provided for determining chloride and chlorine in air at levels of from about 10-1000 parts per billion. The chloride is determined by oxidation to chlorine followed by reduction to chloride in a closed system. Chlorine is determined by direct reduction at a platinum electrode in 6 M H.sub.2 SO.sub.4 electrolyte. A fully automated system is utilized to (1) acquire and store a value corresponding to electrolyte-containing impurities, (2) subtract this value from that obtained in the presence of air, (3) generate coulometrically a standard sample of chlorine mixed with air sample, and determine it as chlorine and/or chloride, and (4) calculate, display, and store for permanent record the ratio of the signal obtained from the air sample and that obtained with the standard.

Electrochemistry of the Hall-Heroult Process for Aluminum Smelting.

ERIC Educational Resources Information Center

Haupin, W. E.

1983-01-01

Nearly all aluminum is produced by the electrolysis of alumina dissolved in a molten cryolite-based electrolyte, the Hall-Heroult Process. Various aspects of the procedure are discussed, focusing on electrolyte chemistry, dissolution of alumina, electrode reactions, current efficiency, and cell voltage. Suggestions for graduate study related to…

Light emission from organic single crystals operated by electrolyte doping

NASA Astrophysics Data System (ADS)

Matsuki, Keiichiro; Sakanoue, Tomo; Yomogida, Yohei; Hotta, Shu; Takenobu, Taishi

2018-03-01

Light-emitting devices based on electrolytes, such as light-emitting electrochemical cells (LECs) and electric double-layer transistors (EDLTs), are solution-processable devices with a very simple structure. Therefore, it is necessary to apply this device structure into highly fluorescent organic materials for future printed applications. However, owing to compatibility problems between electrolytes and organic crystals, electrolyte-based single-crystal light-emitting devices have not yet been demonstrated. Here, we report on light-emitting devices based on organic single crystals and electrolytes. As the fluorescent materials, α,ω-bis(biphenylyl)terthiophene (BP3T) and 5,6,11,12-tetraphenylnaphthacene (rubrene) single crystals were selected. Using ionic liquids as electrolytes, we observed clear light emission from BP3T LECs and rubrene EDLTs.

Numerical investigation and thermodynamic analysis of the effect of electrolyte flow rate on performance of all vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Khazaeli, Ali; Vatani, Ali; Tahouni, Nassim; Panjeshahi, Mohammad Hassan

2015-10-01

In flow batteries, electrolyte flow rate plays a crucial role on the minimizing mass transfer polarization which is at the compensation of higher pressure drop. In this work, a two-dimensional numerical method is applied to investigate the effect of electrolyte flow rate on cell voltage, maximum depth of discharge and pressure drop a six-cell stack of VRFB. The results show that during the discharge process, increasing electrolyte flow rate can raise the voltage of each cell up to 50 mV on average. Moreover, the maximum depth of discharge dramatically increases with electrolyte flow rate. On the other hand, the pressure drop also positively correlates with electrolyte flow rate. In order to investigate all these effects simultaneously, average energy and exergy efficiencies are introduced in this study for the transient process of VRFB. These efficiencies give insight into choosing an appropriate strategy for the electrolyte flow rate. Finally, the energy efficiency of electricity storage using VRFB is investigated and compared with other energy storage systems. The results illustrate that this kind of battery has at least 61% storage efficiency based on the second law of thermodynamics, which is considerably higher than that of their counterparts.

U.S. Clean Energy Hydrogen and Fuel Cell Technologies: A Competitiveness Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fullenkamp, Patrick; Holody, Diane; James, Brian

The objectives of this project are a 1) Global Competitiveness Analysis of hydrogen and fuel cell systems and components manufactured including 700 bar compressed hydrogen storage system in the U.S., Europe, Asia, and other key areas to be identified to determine the global cost leaders, the best current manufacturing processes, the key factors determining competitiveness, and the potential means of cost reductions; and an 2) Analysis to assess the status of global hydrogen and fuel cell markets. The analysis of units, megawatts by country and by application will focus on polymer electrolyte membrane (PEM) fuel cell systems (automotive and stationary).

Spectroscopic and Electrochemical Studies of the Transition Metal Tetrasulfonated Phthalocyanines. Part 5. Voltammetric Studies of Adsorbed Tetrasulfonated Phthalocyanines (MTsPc) in Aqueous Solutions.

DTIC Science & Technology

1985-10-01

atmosphere Immediately after addition of M-TsPc to the supporting electrolyte, the first potential sweep over the given range (e.g., -0.8 to 0.3 V vs. SCE...vs. a-Pd/H electrode) at a sweep rate of 100 mV/s, voltammetric peaks of the hydrogen adsorption/desorption and oxide forma- tion/reduction processes...high sweep rates, e.g., 20 V/s. An OPG electrode standing at open-circuit potential in a Fe(III)-TsPc at potentials between peaks 3 and 4 in Fig. 1

Aluminum reduction cell electrode

DOEpatents

Goodnow, Warren H.; Payne, John R.

1982-01-01

The invention is directed to cathode modules comprised of refractory hard metal materials, such as TiB.sub.2, for an electrolytic cell for the reduction of alumina wherein the modules may be installed and replaced during operation of the cell and wherein the structure of the cathode modules is such that the refractory hard metal materials are not subjected to externally applied forces or rigid constraints.

Electrocatalysis for oxygen electrodes in fuel cells and water electrolyzers for space applications

NASA Technical Reports Server (NTRS)

Prakash, Jai; Tryk, Donald; Yeager, Ernest

1989-01-01

In most instances separate electrocatalysts are needed to promote the reduction of O2 in the fuel cell mode and to generate O2 in the energy storage-water electrolysis mode in aqueous electrochemical systems operating at low and moderate temperatures (T greater than or equal to 200 C). Interesting exceptions are the lead and bismuth ruthenate pyrochlores in alkaline electrolytes. These catalysts on high area carbon supports have high catalytic activity for both O2 reduction and generation. Rotating ring-disk electrode measurements provide evidence that the O2 reduction proceeds by a parallel four-electron pathway. The ruthenates can also be used as self-supported catalysts to avoid the problems associated with carbon oxidation, but the electrode performance so far achieved in the research at Case Western Reserve University (CWRU) is considerably less. At the potentials involved in the anodic mode the ruthenate pyrochlores have substantial equilibrium solubility in concentrated alkaline electrolyte. This results in the loss of catalyst into the bulk solution and a decline in catalytic activity. Furthermore, the hydrogen generation counter electrode may become contaminated with reduction products from the pyrochlores (lead, ruthenium).

Evolution of thermal stress and failure probability during reduction and re-oxidation of solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Wang, Yu; Jiang, Wenchun; Luo, Yun; Zhang, Yucai; Tu, Shan-Tung

2017-12-01

The reduction and re-oxidation of anode have significant effects on the integrity of the solid oxide fuel cell (SOFC) sealed by the glass-ceramic (GC). The mechanical failure is mainly controlled by the stress distribution. Therefore, a three dimensional model of SOFC is established to investigate the stress evolution during the reduction and re-oxidation by finite element method (FEM) in this paper, and the failure probability is calculated using the Weibull method. The results demonstrate that the reduction of anode can decrease the thermal stresses and reduce the failure probability due to the volumetric contraction and porosity increasing. The re-oxidation can result in a remarkable increase of the thermal stresses, and the failure probabilities of anode, cathode, electrolyte and GC all increase to 1, which is mainly due to the large linear strain rather than the porosity decreasing. The cathode and electrolyte fail as soon as the linear strains are about 0.03% and 0.07%. Therefore, the re-oxidation should be controlled to ensure the integrity, and a lower re-oxidation temperature can decrease the stress and failure probability.

Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

NASA Astrophysics Data System (ADS)

Liu, Q. L.; Fu, C. J.; Chan, S. H.; Pasciak, G.

2011-06-01

In this study, a co-tape casting and co-sintering process has been developed to prepare yttria-stabilized zirconia (YSZ) electrolyte films supported on Ni-YSZ anode substrates in order to substantially reduce the fabrication cost of solid oxide fuel cells (SOFC). Through proper control of the process, the anode/electrolyte bilayer structures with a size of 7.8cm × 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 μm in thickness, highly dense, crack free and well-bonded to the anode support. The electrochemical properties of the prepared anode-supported electrolyte film was evaluated in a button cell mode incorporating a (LaSr)MnO3-YSZ composite cathode. With humidified hydrogen as the fuel and stationary air as the oxidant, the cell demonstrated an open-circuit voltage of 1.081 V and a maximum power density of 1.01 W/cm2 at 800°C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.

Low cost silicon solar array project silicon materials task

NASA Technical Reports Server (NTRS)

1977-01-01

A program was established to develop a high temperature silicon production process using existing electric arc heater technology. Silicon tetrachloride and a reductant will be injected into an arc heated mixture of hydrogen and argon. Under these high temperature conditions, a very rapid reaction is expected to occur and proceed essentially to completion, yielding silicon and gaseous sodium chloride. Techniques for high temperature separation and collection of the molten silicon will be developed using standard engineering approaches, and the salt vapor will later be electrolytically separated into its elemental constituents for recycle. Preliminary technical evaluations and economic projections indicate not only that this process appears to be feasible, but that it also has the advantages of rapid, high capacity production of good quality molten silicon at a nominal cost.

Effects of temperature and gas-liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO2 reduction electrocatalysts.

PubMed

Lobaccaro, Peter; Singh, Meenesh R; Clark, Ezra Lee; Kwon, Youngkook; Bell, Alexis T; Ager, Joel W

2016-09-29

In the last few years, there has been increased interest in electrochemical CO 2 reduction (CO2R). Many experimental studies employ a membrane separated, electrochemical cell with a mini H-cell geometry to characterize CO2R catalysts in aqueous solution. This type of electrochemical cell is a mini-chemical reactor and it is important to monitor the reaction conditions within the reactor to ensure that they are constant throughout the study. We show that operating cells with high catalyst surface area to electrolyte volume ratios (S/V) at high current densities can have subtle consequences due to the complexity of the physical phenomena taking place on electrode surfaces during CO2R, particularly as they relate to the cell temperature and bulk electrolyte CO 2 concentration. Both effects were evaluated quantitatively in high S/V cells using Cu electrodes and a bicarbonate buffer electrolyte. Electrolyte temperature is a function of the current/total voltage passed through the cell and the cell geometry. Even at a very high current density, 20 mA cm -2 , the temperature increase was less than 4 °C and a decrease of <10% in the dissolved CO 2 concentration is predicted. In contrast, limits on the CO 2 gas-liquid mass transfer into the cells produce much larger effects. By using the pH in the cell to measure the CO 2 concentration, significant undersaturation of CO 2 is observed in the bulk electrolyte, even at more modest current densities of 10 mA cm -2 . Undersaturation of CO 2 produces large changes in the faradaic efficiency observed on Cu electrodes, with H 2 production becoming increasingly favored. We show that the size of the CO 2 bubbles being introduced into the cell is critical for maintaining the equilibrium CO 2 concentration in the electrolyte, and we have designed a high S/V cell that is able to maintain the near-equilibrium CO 2 concentration at current densities up to 15 mA cm -2 .

Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO 2 reduction electrocatalysts

DOE PAGES

Lobaccaro, Peter; Singh, Meenesh R.; Clark, Ezra Lee; ...

2016-09-06

In the last few years, there has been increased interest in electrochemical CO 2 reduction (CO2R). Many experimental studies employ a membrane separated, electrochemical cell with a mini H-cell geometry to characterize CO2R catalysts in aqueous solution. This type of electrochemical cell is a mini-chemical reactor and it is important to monitor the reaction conditions within the reactor to ensure that they are constant throughout the study. Here we show that operating cells with high catalyst surface area to electrolyte volume ratios (S/V) at high current densities can have subtle consequences due to the complexity of the physical phenomena takingmore » place on electrode surfaces during CO2R, particularly as they relate to the cell temperature and bulk electrolyte CO 2 concentration. Both effects were evaluated quantitatively in high S/V cells using Cu electrodes and a bicarbonate buffer electrolyte. Electrolyte temperature is a function of the current/total voltage passed through the cell and the cell geometry. Even at a very high current density, 20 mA cm -2 , the temperature increase was less than 4 °C and a decrease of < 10% in the dissolved CO 2 concentration is predicted. In contrast, limits on the CO 2 gas-liquid mass transfer into the cells produce much larger effects. By using the pH in the cell to measure the CO 2 concentration, significant undersaturation of CO 2 is observed in the bulk electrolyte, even at more modest current densities of 10 mA cm -2 . Undersaturation of CO 2 produces large changes in the faradaic efficiency observed on Cu electrodes, with H 2 production becoming increasingly favored. Finally, we show that the size of the CO 2 bubbles being introduced into the cell is critical for maintaining the equilibrium CO 2 concentration in the electrolyte, and we have designed a high S/V cell that is able to maintain the near-equilibrium CO 2 concentration at current densities up to 15 mA cm -2.« less

Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO 2 reduction electrocatalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobaccaro, Peter; Singh, Meenesh R.; Clark, Ezra Lee

In the last few years, there has been increased interest in electrochemical CO 2 reduction (CO2R). Many experimental studies employ a membrane separated, electrochemical cell with a mini H-cell geometry to characterize CO2R catalysts in aqueous solution. This type of electrochemical cell is a mini-chemical reactor and it is important to monitor the reaction conditions within the reactor to ensure that they are constant throughout the study. Here we show that operating cells with high catalyst surface area to electrolyte volume ratios (S/V) at high current densities can have subtle consequences due to the complexity of the physical phenomena takingmore » place on electrode surfaces during CO2R, particularly as they relate to the cell temperature and bulk electrolyte CO 2 concentration. Both effects were evaluated quantitatively in high S/V cells using Cu electrodes and a bicarbonate buffer electrolyte. Electrolyte temperature is a function of the current/total voltage passed through the cell and the cell geometry. Even at a very high current density, 20 mA cm -2 , the temperature increase was less than 4 °C and a decrease of < 10% in the dissolved CO 2 concentration is predicted. In contrast, limits on the CO 2 gas-liquid mass transfer into the cells produce much larger effects. By using the pH in the cell to measure the CO 2 concentration, significant undersaturation of CO 2 is observed in the bulk electrolyte, even at more modest current densities of 10 mA cm -2 . Undersaturation of CO 2 produces large changes in the faradaic efficiency observed on Cu electrodes, with H 2 production becoming increasingly favored. Finally, we show that the size of the CO 2 bubbles being introduced into the cell is critical for maintaining the equilibrium CO 2 concentration in the electrolyte, and we have designed a high S/V cell that is able to maintain the near-equilibrium CO 2 concentration at current densities up to 15 mA cm -2.« less

Solid electrolyte material manufacturable by polymer processing methods

DOEpatents

Singh, Mohit; Gur, Ilan; Eitouni, Hany Basam; Balsara, Nitash Pervez

2012-09-18

The present invention relates generally to electrolyte materials. According to an embodiment, the present invention provides for a solid polymer electrolyte material that is ionically conductive, mechanically robust, and can be formed into desirable shapes using conventional polymer processing methods. An exemplary polymer electrolyte material has an elastic modulus in excess of 1.times.10.sup.6 Pa at 90 degrees C. and is characterized by an ionic conductivity of at least 1.times.10.sup.-5 Scm-1 at 90 degrees C. An exemplary material can be characterized by a two domain or three domain material system. An exemplary material can include material components made of diblock polymers or triblock polymers. Many uses are contemplated for the solid polymer electrolyte materials. For example, the present invention can be applied to improve Li-based batteries by means of enabling higher energy density, better thermal and environmental stability, lower rates of self-discharge, enhanced safety, lower manufacturing costs, and novel form factors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hui; Chen, Yan; Hood, Zachary D.

All-solid-state sodium batteries, using abundant sodium resources and solid electrolyte, hold much promise for safe, low cost, large-scale energy storage. To realize the practical applications of all solid Na-ion batteries at ambient temperature, the solid electrolytes are required to have high ionic conductivity, chemical stability, and ideally, easy preparation. Ceramic electrolytes show higher ionic conductivity than polymers, but they often require extremely stringent synthesis conditions, either high sintering temperature above 1000 C or long-time, low-energy ball milling. Herein, we report a new synthesis route for Na 3SbS 4, a novel Na superionic conductor that needs much lower processing temperature belowmore » 200 C and easy operation. This new solid electrolyte exhibits a remarkable ionic conductivity of 1.05 mS cm -1 at 25 °C and is chemically stable under ambient atmosphere. In conclusion, this synthesis process provides unique insight into the current state-of-the-art solid electrolyte preparation and opens new possibilities for the design of similar materials.« less

Purely electronic mechanism of electrolyte gating of indium tin oxide thin films

DOE PAGES

Leng, X.; Bozovic, I.; Bollinger, A. T.

2016-08-10

Epitaxial indium tin oxide films have been grown on both LaAlO 3 and yttria-stabilized zirconia substrates using RF magnetron sputtering. Electrolyte gating causes a large change in the film resistance that occurs immediately after the gate voltage is applied, and shows no hysteresis during the charging/discharging processes. When two devices are patterned next to one another and the first one gated through an electrolyte, the second one shows no changes in conductance, in contrast to what happens in materials (like tungsten oxide) susceptible to ionic electromigration and intercalation. These findings indicate that electrolyte gating in indium tin oxide triggers amore » pure electronic process (electron depletion or accumulation, depending on the polarity of the gate voltage), with no electrochemical reactions involved. Electron accumulation occurs in a very thin layer near the film surface, which becomes highly conductive. These results contribute to our understanding of the electrolyte gating mechanism in complex oxides and may be relevant for applications of electric double layer transistor devices.« less

Na3Si2Y0.16Zr1.84PO12-ionic liquid hybrid electrolytes: An approach for realizing solid-state sodium-ion batteries?

NASA Astrophysics Data System (ADS)

de la Torre-Gamarra, Carmen; Appetecchi, Giovanni Battista; Ulissi, Ulderico; Varzi, Alberto; Varez, Alejandro; Passerini, Stefano

2018-04-01

Ceramic electrolytes are prepared through sintering processes which are carried out at high temperatures and require prolonged operating times, resulting unwelcome in industrial applications. We report a physicochemical characterization on hybrid, sodium conducting, electrolyte systems obtained by coating NASICON ceramic powders with the N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid. The goal is to realize a ceramic-IL interface with improved sodium mobility, aiming to obtain a solid electrolyte with high ion transport properties but avoiding sintering thermal treatment. The purpose of the present work, however, is showing how simply combining NASICON powder and Py14TFSI does not lead to any synergic effect on the resulting hybrid electrolyte, evidencing that an average functionalization of the ceramic powder surface and/or ionic liquid is needed. Also, the processing conditions for preparing the hybrid samples are found to affect their ion transport properties.

InGaN/GaN quantum dots as optical probes for the electric field at the GaN/electrolyte interface

NASA Astrophysics Data System (ADS)

Teubert, J.; Koslowski, S.; Lippert, S.; Schäfer, M.; Wallys, J.; Dimitrakopulos, G.; Kehagias, Th.; Komninou, Ph.; Das, A.; Monroy, E.; Eickhoff, M.

2013-08-01

We investigated the electric-field dependence of the photoluminescence-emission properties of InGaN/GaN quantum dot multilayers in contact with an electrolyte. Controlled variations of the surface potential were achieved by the application of external electric fields using the electrolytic Schottky contact and by variation of the solution's pH value. Prior to characterization, a selective electrochemical passivation process was required to suppress leakage currents. The quantum dot luminescence is strongly affected by surface potential variations, i.e., it increases exponentially with cathodic bias and acidic pH values. The results cannot be explained by a modification of intra-dot polarization induced electric fields via the quantum confined Stark effect but are attributed to the suppression/enhancement of non-radiative recombination processes, i.e., mainly hole transfer into the electrolyte. The results establish a link between the photoluminescence intensity and the magnitude of electric fields at the semiconductor/electrolyte interface.

Equilibrium lithium-ion transport between nanocrystalline lithium-inserted anatase TiO2 and the electrolyte.

PubMed

Ganapathy, Swapna; van Eck, Ernst R H; Kentgens, Arno P M; Mulder, Fokko M; Wagemaker, Marnix

2011-12-23

The power density of lithium-ion batteries requires the fast transfer of ions between the electrode and electrolyte. The achievable power density is directly related to the spontaneous equilibrium exchange of charged lithium ions across the electrolyte/electrode interface. Direct and unique characterization of this charge-transfer process is very difficult if not impossible, and consequently little is known about the solid/liquid ion transfer in lithium-ion-battery materials. Herein we report the direct observation by solid-state NMR spectroscopy of continuous lithium-ion exchange between the promising nanosized anatase TiO(2) electrode material and the electrolyte. Our results reveal that the energy barrier to charge transfer across the electrode/electrolyte interface is equal to or greater than the barrier to lithium-ion diffusion through the solid anatase matrix. The composition of the electrolyte and in turn the solid/electrolyte interface (SEI) has a significant effect on the electrolyte/electrode lithium-ion exchange; this suggests potential improvements in the power of batteries by optimizing the electrolyte composition. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ELECTROLYTIC SEPARATION PROCESS AND APPARATUS

DOEpatents

McLain, M.E. Jr.; Roberts, M.W.

1962-03-01

A method is given for dissolving stainless steel-c lad fuel elements in dilute acids such as half normal sulfuric acid. The fuel element is made the anode in a Y-shaped electrolytic cell which has a flowing mercury cathode; the stainless steel elements are entrained in the mercury and stripped therefrom by a continuous process. (AEC)

Process for electrolytically preparing uranium metal

DOEpatents

Haas, Paul A.

1989-01-01

A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

Electrically conductive anodized aluminum coatings

NASA Technical Reports Server (NTRS)

Alwitt, Robert S. (Inventor); Liu, Yanming (Inventor)

2001-01-01

A process for producing anodized aluminum with enhanced electrical conductivity, comprising anodic oxidation of aluminum alloy substrate, electrolytic deposition of a small amount of metal into the pores of the anodized aluminum, and electrolytic anodic deposition of an electrically conductive oxide, including manganese dioxide, into the pores containing the metal deposit; and the product produced by the process.

Process for electrolytically preparing uranium metal

DOEpatents

Haas, Paul A.

1989-08-01

A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

Electrolytic pretreatment unit gaseous effluent conditioning

NASA Technical Reports Server (NTRS)

Colombo, G. V.; Putnam, D. F.

1976-01-01

The electrolytic pretreatment of urine is an advanced process that eliminates the need for handling and storing the highly corrosive chemicals that are normally used in water reclamation systems. The electrolytic pretreatment process also converts the organic materials in urine to gases (N2 and O2) that can be used to replenish those lost to space by leakage, venting, and air lock operations. The electrolytic process is more than a pretreatment, since it decreases the urine solids content by approximately one third, thus reducing the load and eventual solids storage requirements of the urine processing system. The evolved gases from the pretreatment step cannot, however, be returned directly to the atmosphere of a spacecraft without first removing several impurities including hydrogen, chlorine, and certain organic compounds. A treatment concept was developed that would decrease the impurities in the gas stream that emanates from an electrolysis unit to levels sufficiently low to allow the conditioned gas stream to be safely discharged to a spacecraft atmosphere. Two methods were experimentally demonstrated that can accomplish the desired cleanup. The bases of the two methods are, repectively: (1) raw urine scrubbing and (2) silica gel sorption.

Plutonium recovery from spent reactor fuel by uranium displacement

DOEpatents

Ackerman, J.P.

1992-03-17

A process is described for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

Vanadium proton exchange membrane water electrolyser

NASA Astrophysics Data System (ADS)

Noack, Jens; Roznyatovskaya, Nataliya; Pinkwart, Karsten; Tübke, Jens

2017-05-01

In order to reverse the reactions of vanadium oxygen fuel cells and to regenerate vanadium redox flow battery electrolytes that have been oxidised by atmospheric oxygen, a vanadium proton exchange membrane water electrolyser was set up and investigated. Using an existing cell with a commercial and iridium-based catalyst coated membrane, it was possible to fully reduce V3.5+ and V3+ solutions to V2+ with the formation of oxygen and with coulomb efficiencies of over 96%. The cell achieved a maximum current density of 75 mA/cm2 during this process and was limited by the proximity of the V(III) reduction to the hydrogen evolution reaction. Due to the specific reaction mechanisms of V(IV) and V(III) ions, V(III) solutions were reduced with an energy efficiency of 61%, making this process nearly twice as energy efficient as the reduction of V(IV) to V(III). Polarisation curves and electrochemical impedance spectroscopy were used to further investigate the losses of half-cell reactions and to find ways of further increasing efficiency and performance levels.

Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

NASA Astrophysics Data System (ADS)

Benoved, Nir; Kesler, O.

Air plasma spraying has been used to produce porous composite anodes based on Ce 0.8Sm 0.2O 1.9 (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H 2, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 Ω cm 2 in impedance tests in hydrogen at 712 °C.

Method and system for the removal of oxides of nitrogen and sulfur from combustion processes

DOEpatents

Walsh, John V.

1987-12-15

A process for removing oxide contaminants from combustion gas, and employing a solid electrolyte reactor, includes: (a) flowing the combustion gas into a zone containing a solid electrolyte and applying a voltage and at elevated temperature to thereby separate oxygen via the solid electrolyte, (b) removing oxygen from that zone in a first stream and removing hot effluent gas from that zone in a second stream, the effluent gas containing contaminant, (c) and pre-heating the combustion gas flowing to that zone by passing it in heat exchange relation with the hot effluent gas.

Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation.

PubMed

van Hengel, Ingmar A J; Riool, Martijn; Fratila-Apachitei, Lidy E; Witte-Bouma, Janneke; Farrell, Eric; Zadpoor, Amir A; Zaat, Sebastian A J; Apachitei, Iulian

2017-08-01

Additively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017) [1]. This data shows the changes in surface morphology during plasma electrolytic oxidation. Data presented in this article are related to the research article "Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus" (van Hengel et al., 2017) [1].

Ferronickel Preparation from Nickeliferous Laterite by Rotary Kiln-Electric Furnace Process

NASA Astrophysics Data System (ADS)

Li, Guanghui; Jia, Hao; Luo, Jun; Peng, Zhiwei; Zhang, Yuanbo; Jiang, Tao

Nickel is an important strategic metal, which is mainly used for stainless steel production. In the recent years, ferronickel has been used as a substitute for electrolytic nickel for alleviating the cost of stainless steel production. Rotary kiln-electric furnace (RKEF) smelting is currently the world-wide mainstreaming process for ferronickel production from nickeliferous laterite ore, in spite of the high power consumption. In this study, aiming to provide some meaningful guidance for ferronickel production of RKEF smelting, reductive roasting followed by smelting process was carried out. The conditions including reducing parameters (roasting temperature and time) and smelting parameters (coke dosage, CaO dosage, melting temperature and time) were ascertained. The metal recovery ratios, as well as Ni, Fe, S and P content of ferronickel were considered. The results showed that a ferronickel containing 10. 32 wt. % Ni was obtained from a laterite with 1. 85 wt. % Ni, the nickel recovery ratio was about 99%.

Abstract - Cooperative Research and Development Agreement between Penn State University and National Energy Technology Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hickner, Michael A.; Matranga, Christopher S.

This project will use bipolar membranes to produce efficient vapor-phase electrolysis cells for splitting CO 2 to CO and oxygen. CO is a valuable chemical feedstock that can be combined catalytically with hydrogen in the Fischer-Tropsch process to make liquid fuels. CO is arguably the best target for CO 2 reduction since, as a gaseous product, it is easily collected and is relatively immune to membrane crossover losses. The keys to success in this project are to design and synthesize hydrophilic, low resistance bipolar membranes and to create optimized electrode/catalyst/ electrolyte architectures based on these new membranes and advanced catalystsmore » in order to achieve high current density at low overpotentials for CO 2 conversion. High current density is key to achieving industrially-relevant throughput for the process and low overpotentials maintain high overall efficiency for the process.« less

Critical role of intercalated water for electrocatalytically active nitrogen-doped graphitic systems

DOE PAGES

Martinez, Ulises; Dumont, Joseph H.; Holby, Edward F.; ...

2016-03-18

Graphitic materials are very essential in energy conversion and storage because of their excellent chemical and electrical properties. The strategy for obtaining functional graphitic materials involves graphite oxidation and subsequent dissolution in aqueous media, forming graphene-oxide nanosheets (GNs). Restacked GNs contain substantial intercalated water that can react with heteroatom dopants or the graphene lattice during reduction. We demonstrate that removal of intercalated water using simple solvent treatments causes significant structural reorganization, substantially affecting the oxygen reduction reaction (ORR) activity and stability of nitrogen-doped graphitic systems. Amid contrasting reports describing the ORR activity of GN-based catalysts in alkaline electrolytes, we demonstratemore » superior activity in an acidic electrolyte with an onset potential of ~0.9 V, a half-wave potential (E ½) of 0.71 V, and a selectivity for four-electron reduction of >95%. Finally and further, durability testing showed E ½ retention >95% in N 2- and O 2-saturated solutions after 2000 cycles, demonstrating the highest ORR activity and stability reported to date for GN-based electrocatalysts in acidic media.« less

Aluminum reduction cell electrode

DOEpatents

Goodnow, W.H.; Payne, J.R.

1982-09-14

The invention is directed to cathode modules comprised of refractory hard metal materials, such as TiB[sub 2], for an electrolytic cell for the reduction of alumina wherein the modules may be installed and replaced during operation of the cell and wherein the structure of the cathode modules is such that the refractory hard metal materials are not subjected to externally applied forces or rigid constraints. 9 figs.

For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals

DOEpatents

Ray, Siba P.; Liu, Xinghua; Weirauch, Douglas A.

2002-01-01

A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

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

DOEpatents

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.

Decomposition of the fluoroethylene carbonate additive and the glue effect of lithium fluoride products for the solid electrolyte interphase: an ab initio study.

PubMed

Okuno, Yukihiro; Ushirogata, Keisuke; Sodeyama, Keitaro; Tateyama, Yoshitaka

2016-03-28

Additives in the electrolyte solution of lithium-ion batteries (LIBs) have a large impact on the performance of the solid electrolyte interphase (SEI) that forms on the anode and is a key to the stability and durability of LIBs. We theoretically investigated effects of fluoroethylene carbonate (FEC), a representative additive, that has recently attracted considerable attention for the enhancement of cycling stability of silicon electrodes and the improvement of reversibility of sodium-ion batteries. First, we intensively examined the reductive decompositions by ring-opening, hydrogen fluoride (HF) elimination to form a vinylene carbonate (VC) additive and intermolecular chemical reactions of FEC in the ethylene carbonate (EC) electrolyte, by using density functional theory (DFT) based molecular dynamics and the blue-moon ensemble technique for the free energy profile. The results show that the most plausible product of the FEC reductive decomposition is lithium fluoride (LiF), and that the reactivity of FEC to anion radicals is found to be inert compared to the VC additive. We also investigated the effects of the generated LiF on the SEI by using two model systems; (1) LiF molecules distributed in a model aggregate of organic SEI film components (SFCs) and (2) a LiF aggregate interfaced with the SFC aggregate. DFT calculations of the former system show that F atoms form strong bindings with the Li atoms of multiple organic SFC molecules and play as a joint connecting them. In the latter interface system, the LiF aggregate adsorbs the organic SFCs through the F-Li bindings. These results suggest that LiF moieties play the role of glue in the organic SFC within the SEI film. We also examined the interface structure between a LiF aggregate and a lithiated silicon anode, and found that they are strongly bound. This strong binding is likely to be related to the effectiveness of the FEC additive in the electrolyte for the silicon anode.

Exploring electrolyte preference of vanadium nitride supercapacitor electrodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bo; Chen, Zhaohui; Lu, Gang

Highlights: • Hierarchical VN nanostructures were prepared on graphite foam. • Electrolyte preference of VN supercapacitor electrodes was explored. • VN showed better capacitive property in organic and alkaline electrolytes than LiCl. - Abstract: Vanadium nitride hierarchical nanostructures were prepared through an ammonia annealing procedure utilizing vanadium pentoxide nanostructures grown on graphite foam. The electrochemical properties of hierarchical vanadium nitride was tested in aqueous and organic electrolytes. As a result, the vanadium nitride showed better capacitive energy storage property in organic and alkaline electrolytes. This work provides insight into the charge storage process of vanadium nitride and our findings canmore » shed light on other transition metal nitride-based electrochemical energy storage systems.« less

Health effects of desalinated water: Role of electrolyte disturbance in cancer development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nriagu, Jerome, E-mail: jnriagu@umich.edu

This review contends that “healthy” water in terms of electrolyte balance is as important as “pure” water in promoting public health. It considers the growing use of desalination (demineralization) technologies in drinking water treatment which often results in tap water with very low concentrations of sodium, potassium, magnesium and calcium. Ingestion of such water can lead to electrolyte abnormalities marked by hyponatremia, hypokalemia, hypomagnesemia and hypocalcemia which are among the most common and recognizable features in cancer patients. The causal relationships between exposure to demineralized water and malignancies are poorly understood. This review highlights some of the epidemiological and inmore » vivo evidence that link dysregulated electrolyte metabolism with carcinogenesis and the development of cancer hallmarks. It discusses how ingestion of demineralized water can have a procarcinogenic effect through mediating some of the critical pathways and processes in the cancer microenvironment such as angiogenesis, genomic instability, resistance to programmed cell death, sustained proliferative signaling, cell immortalization and tumorigenic inflammation. Evidence that hypoosmotic stress-response processes can upregulate a number of potential oncogenes is well supported by a number studies. In view of the rising production and consumption of demineralized water in most parts of the world, there is a strong need for further research on the biological importance and protean roles of electrolyte abnormalities in promoting, antagonizing or otherwise enabling the development of cancer. The countries of the Gulf Cooperative Council (GCC) where most people consume desalinated water would be a logical place to start this research. - Highlights: • Ingestion of low-mineral waters disrupts electrolyte homeostasis and cellular processes. • Electrolyte imbalance can affect the tumor microenvironment and many stages of tumorigenesis. • Electrolyte disturbance is frequently encountered in patients with malignancies. • Desalinated water consumption and cancer rates are rising in Persian Gulf countries “Balanced water” can be as important as balanced diet in safeguarding our health.« less

Spectroscopic investigation of plasma electrolytic borocarburizing on q235 low-carbon steel

NASA Astrophysics Data System (ADS)

Liu, Run; Wang, Bin; Wu, Jie; Xue, Wenbin; Jin, Xiaoyue; Du, Jiancheng; Hua, Ming

2014-12-01

A plasma electrolytic borocarburizing process (PEB/C) in borax electrolyte with glycerin additive was employed to fabricate a hardening layer on Q235 low-carbon steel. Optical emission spectroscopy (OES) was utilized to investigate the spectroscopy characteristics of plasma discharge around the steel during PEB/C process. Some plasma parameters were calculated in terms of OES. The electron temperature and electron concentration in plasma discharge zone is about 3000-12,000 K and 2 × 1022 m-3-1.4 × 1023 m-3. The atomic ionization degrees of iron, carbon and boron are 10-16-10-3, and 10-23-10-6, 10-19-10-4, respectively, which depend on discharge time. The surface morphology and cross-sectional microstructure of PEB/C hardening layer were observed, and the electrolyte decomposition and plasma discharge behaviors were discussed.

Study on electrochemically deposited Mg metal

NASA Astrophysics Data System (ADS)

Matsui, Masaki

An electrodeposition process of magnesium metal from Grignard reagent based electrolyte was studied by comparing with lithium. The electrodeposition of magnesium was performed at various current densities. The obtained magnesium deposits did not show dendritic morphologies while all the lithium deposits showed dendritic products. Two different crystal growth modes in the electrodeposition process of magnesium metal were confirmed by an observation using scanning electron micro scope (SEM) and a crystallographic analysis using X-ray diffraction (XRD). An electrochemical study of the deposition/dissolution process of the magnesium showed a remarkable dependency of the overpotential of magnesium deposition on the electrolyte concentration compared with lithium. This result suggests that the dependency of the overpotential on the electrolyte concentration prevent the locally concentrated current resulting to form very uniform deposits.

Titania nanotube powders obtained by rapid breakdown anodization in perchloric acid electrolytes

NASA Astrophysics Data System (ADS)

Ali, Saima; Hannula, Simo-Pekka

2017-05-01

Titania nanotube (TNT) powders are prepared by rapid break down anodization (RBA) in a 0.1 M perchloric acid (HClO4) solution (Process 1), and ethylene glycol (EG) mixture with HClO4 and water (Process 2). A study of the as-prepared and calcined TNT powders obtained by both processes is implemented to evaluate and compare the morphology, crystal structure, specific surface area, and the composition of the nanotubes. Longer TNTs are formed in Process 1, while comparatively larger pore diameter and wall thickness are obtained for the nanotubes prepared by Process 2. The TNTs obtained by Process 1 are converted to nanorods at 350 °C, while nanotubes obtained by Process 2 preserve tubular morphology till 350 °C. In addition, the TNTs prepared by an aqueous electrolyte have a crystalline structure, whereas the TNTs obtained by Process 2 are amorphous. Samples calcined till 450 °C have XRD peaks from the anatase phase, while the rutile phase appears at 550 °C for the TNTs prepared by both processes. The Raman spectra also show clear anatase peaks for all samples except the as-prepared sample obtained by Process 2, thus supporting the XRD findings. FTIR spectra reveal the presence of O-H groups in the structure for the TNTs obtained by both processes. However, the presence is less prominent for annealed samples. Additionally, TNTs obtained by Process 2 have a carbonaceous impurity present in the structure attributed to the electrolyte used in that process. While a negligible weight loss is typical for TNTs prepared from aqueous electrolytes, a weight loss of 38.6% in the temperature range of 25-600 °C is found for TNTs prepared in EG electrolyte (Process 2). A large specific surface area of 179.2 m2 g-1 is obtained for TNTs prepared by Process 1, whereas Process 2 produces nanotubes with a lower specific surface area. The difference appears to correspond to the dimensions of the nanotubes obtained by the two processes.

Polymer Electrolyte Through Enzyme Catalysis for High Performance Lithium-Ion Batteries

DTIC Science & Technology

1998-10-16

by block number) FIELD GROUP SUB-GROUP Polymer Electrolyte, Solid State, Enzyme Catalysis, Lithium - Ion Battery , Sol Gel, High Conductivity 19...excellent candidates for lithium - ion battery development. Furthermore, the processes used to achieve the final product yield very good mechanical properties...Objectives This research was initiated to investigate synthesis of improved polymer electrolytes for lithium - ion battery applications. The overall

Betavoltaic Enhancement Using Defect-Engineered TiO2 Nanotube Arrays through Electrochemical Reduction in Organic Electrolytes.

PubMed

Ma, Yang; Wang, Na; Chen, Jiang; Chen, Changsong; San, Haisheng; Chen, Jige; Cheng, Zhengdong

2018-06-19

Utilizing high-energy beta particles emitted from radioisotopes for long-lifetime betavoltaic cells is a great challenge due to low energy conversion efficiency. Here, we report a betavoltaic cell fabricated using TiO 2 nanotube arrays (TNTAs) electrochemically reduced in ethylene glycol electrolyte (EGECR-TNTAs) for the enhancement of the betavoltaic effect. The electrochemical reduction of TNTAs using high cathodic bias in organic electrolytes is indeed a facile and effective strategy to induce in situ self-doping of oxygen vacancy (OV) and Ti 3+ defects. The black EGECR-TNTAs are highly stable with a significantly narrower band gap and higher electrical conductivity as well as UV-vis-NIR light absorption. A 20 mCi of 63 Ni betavoltaic cell based on the reduced TNTAs exhibits a maximum ECE of 3.79% with open-circuit voltage of 1.04 V, short-circuit current density of 117.5 nA cm -2 , and a maximum power density of 39.2 nW cm -2 . The betavoltaic enhancement can be attributed to the enhanced charge carrier transport and separation as well as multiple exciton generation of electron-hole pairs due the generation of OV and Ti 3+ interstitial bands below the conductive band of TiO 2.

Molecular dynamics simulations of the first charge of a Li-ion-Si-anode nanobattery.

PubMed

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 the solid electrolyte interphase in the anode. Graphical Abstract Nanobattery: LiCoO 2 cathode, electrolyte solution of 1M Li + PF 6 - in ethylene carbonate, and Si crystal anode, which changes its volume due to lithiation during the first charge.

In situ solid-state electrochemistry of mass-selected ions at well-defined electrode–electrolyte interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prabhakaran, Venkateshkumar; Johnson, Grant E.; Wang, Bingbing

2016-11-07

Molecular-level understanding of electrochemical processes occurring at electrode-electrolyte interfaces (EEI) is key to the rational development of high-performance and sustainable electrochemical technologies. This article reports the development and first application of solid-state in situ electrochemical probes to study redox and catalytic processes occurring at well-defined EEI generated using soft-landing of mass- and charge-selected cluster ions (SL). In situ electrochemical probes with excellent mass transfer properties are fabricated using carefully-designed nanoporous ionic liquid membranes. SL enables deposition of pure active species that are not obtainable with other techniques onto electrode surfaces with precise control over charge state, composition, and kinetic energy.more » SL is, therefore, a unique tool for studying fundamental processes occurring at EEI. For the first time using an aprotic electrochemical probe, the effect of charge state (PMo12O403-/2-) and the contribution of building blocks of Keggin polyoxometalate (POM) clusters to redox processes are characterized by populating EEI with novel POM anions generated by electrospray ionization and gas phase dissociation. Additionally, a proton conducting electrochemical probe has been developed to characterize the reactive electrochemistry (oxygen reduction activity) of bare Pt clusters (Pt40 ~1 nm diameter), thus demonstrating the capability of the probe for studying reactions in controlled gaseous environments. The newly developed in situ electrochemical probes combined with ion SL provide a versatile method to characterize the EEI in solid-state redox systems and reactive electrochemistry at precisely-defined conditions. This capability will advance molecular-level understanding of processes occurring at EEI that are critical to many energy-related technologies.« less

Conductivity studies of PEG based polymer electrolyte for applications as electrolyte in ion batteries

NASA Astrophysics Data System (ADS)

Patil, Ravikumar V.; Praveen, D.; Damle, R.

2018-05-01

Development of lithium ion batteries employing solid polymer electrolytes as electrolyte material has led to efficient energy storage and usage in many portable devices. However, due to a few drawbacks like lower ionic conductivity of solid polymer electrolytes (SPEs), studies on SPEs for improvement in conductivity still have a good scope. In the present paper, we report the conductivity studies of a new SPE with low molecular weight poly ethylene glycol (PEG) as host polymer in which a salt with larger anion Lithium trifluro methane sulphonate (LTMS). XRD studies have revealed that the salt completely dissociates in the polymer giving a good stable electrolyte at lower salt concentration. Conductivity of the SPEs has been studied as a function of temperature and we reiterate that the conductivity is a thermally activated process and follows Arrhenius type behavior.

The role of electrolyte and polyelectrolyte on the adsorption of the anionic surfactant, sodium dodecylbenzenesulfonate, at the air-water interface.

PubMed

Zhang, X L; Taylor, D J F; Thomas, R K; Penfold, J

2011-04-15

The role of the polyelectrolyte, poly(ethyleneimine), PEI, and the electrolytes NaCl and CaCl(2), on the adsorption of the anionic surfactant, sodium dodecylbenzenesulfonate, LAS, at the air-water interface have been investigated by neutron reflectivity and surface tension. The surface tension data for the PEI/LAS mixtures are substantially affected by pH and the addition of electrolyte, and are consistent with a strong adsorption of surface polymer/surfactant complexes down to relatively low surfactant concentrations. The effects are most pronounced at high pH, and this is confirmed by the adsorption data obtained directly from neutron reflectivity. However, the effects of the addition of PEI and electrolyte on the LAS adsorption are not as pronounced as previously reported for PEI/SDS mixtures. This is attributed primarily to the steric hindrance of the LAS phenyl group resulting in a reduction in the ion-dipole attraction between the LAS sulfonate and amine groups that dominates the interaction at high pH. Copyright © 2011 Elsevier Inc. All rights reserved.

Electrochemical reduction of UO2 in LiCl-Li2O molten salt using porous and nonporous anode shrouds

NASA Astrophysics Data System (ADS)

Choi, Eun-Young; Won, Chan Yeon; Cha, Ju-Sun; Park, Wooshin; Im, Hun Suk; Hong, Sun-Seok; Hur, Jin-Mok

2014-01-01

Electrochemical reductions of uranium oxide in a molten LiCl-Li2O electrolyte were carried out using porous and nonporous anode shrouds. The study focused on the effect of the type of anode shroud on the current density by running experiments with six anode shrouds. Dense ceramics, MgO, and MgO (3 wt%) stabilized ZrO2 (ZrO2-MgO) were used as nonporous shrouds. STS 20, 100, and 300 meshes and ZrO2-MgO coated STS 40 mesh were used as porous shrouds. The current densities (0.34-0.40 A cm-2) of the electrolysis runs using the nonporous anode shrouds were much lower than those (0.76-0.79 A cm-2) of the runs using the porous shrouds. The ZrO2-MgO shroud (600-700 MPa at 25 °C) showed better bending strength than that of MgO (170 MPa at 25 °C). The high current densities achieved in the electrolysis runs using the porous anode shrouds were attributed to the transport of O2- ions through the pores in meshes of the shroud wall. ZrO2-MgO coating on STS mesh was chemically unstable in a molten LiCl-Li2O electrolyte containing Li metal. The electrochemical reduction runs using STS 20, 100, and 300 meshes showed similar current densities in spite of their different opening sizes. The STS mesh shrouds which were immersed in a LiCl-Li2O electrolyte were stable without any damage or corrosion.

Bi-Sr-Ca-Cu-O and Pb-Bi-Sr-Ca-Cu-O superconductor films via an electrodeposition process

NASA Astrophysics Data System (ADS)

Maxfield, M.; Eckhardt, H.; Iqbal, Z.; Reidinger, F.; Baughman, R. H.

1989-05-01

A novel electrochemical process has been developed for the formation of superconducting films. Using this process, superconducting films of Bi2Sr2Ca1Cu2O8 and (Pb,Bi)2Sr2Ca1Cu2O8 have been formed. The process consists of simultaneously depositing the metallic constituents of the superconductor from a single electrolyte, and thermally oxidizing the resulting precursors film to form the superconducting phase. Application of -4 to -5 V vs Ag/Ag(+) to a conductive cathode substrate which is immersed in an electrolyte containing salts of all of the metals reduces the metal cations, causing then to deposit on the cathode as a metallic film precursor. Precursor films having desired stoichiometries were obtained by regulating the electrolyte bath composition.

Molten salt bath circulation design for an electrolytic cell

DOEpatents

Dawless, Robert K.; LaCamera, Alfred F.; Troup, R. Lee; Ray, Siba P.; Hosler, Robert B.

1999-01-01

An electrolytic cell for reduction of a metal oxide to a metal and oxygen has an inert anode and an upwardly angled roof covering the inert mode. The angled roof diverts oxygen bubbles into an upcomer channel, thereby agitating a molten salt bath in the upcomer channel and improving dissolution of a metal oxide in the molten salt bath. The molten salt bath has a lower velocity adjacent the inert anode in order to minimize corrosion by substances in the bath. A particularly preferred cell produces aluminum by electrolysis of alumina in a molten salt bath containing aluminum fluoride and sodium fluoride.

Electrochemical micro sensor

DOEpatents

Setter, Joseph R.; Maclay, G. Jordan

1989-09-12

A micro-amperometric electrochemical sensor for detecting the presence of a pre-determined species in a fluid material is disclosed. The sensor includes a smooth substrate having a thin coating of solid electrolytic material deposited thereon. The working and counter electrodes are deposited on the surface of the solid electrolytic material and adhere thereto. Electrical leads connect the working and counter electrodes to a potential source and an apparatus for measuring the change in an electrical signal caused by the electrochemical oxidation or reduction of the species. Alternatively, the sensor may be fabricated in a sandwich structure and also may be cylindrical, spherical or other shapes.

The electrocatalytic reduction of nitrate in water on Pd/Sn-modified activated carbon fiber electrode.

PubMed

Wang, Ying; Qu, Jiuhui; Wu, Rongcheng; Lei, Pengju

2006-03-01

The Pd/Sn-modified activated carbon fiber (ACF) electrodes were successfully prepared by the impregnation of Pd2+ and Sn2+ ions onto ACF, and their electrocatalytic reduction capacity for nitrate ions in water was evaluated in a batch experiment. The electrode was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and temperature programmed reduction (TPR). The capacity for nitrate reduction depending on Sn content on the electrode and the pH of electrolyte was discussed at length. The results showed that at an applied current density of 1.11 mA cm(-2), nitrate ions in water (solution volume: 400 mL) were reduced from 110 to 3.4 mg L(-1) after 240 min with consecutive change of intermediate nitrite. Ammonium ions and nitrogen were formed as the main final products. The amount of other possible gaseous products (including NO and N2O) was trace. With the increase of Sn content on the Pd/Sn-modified ACF electrode, the activity for nitrate reduction went up to reach a maximum (at Pd/Sn = 4) and then decreased, while the selectivity to N2 was depressed. Higher pH value of electrolyte exhibited more suppression effect on the reduction of nitrite than that of nitrate. However, no significant influence on the final ammonia formation was observed. Additionally, Cu ion in water was found to cover the active sites of the electrode to make the electrode deactivated.

A method for making an alkaline battery electrode plate

NASA Technical Reports Server (NTRS)

Chida, K.; Ezaki, T.

1983-01-01

A method is described for making an alkaline battery electrode plate where the desired active substances are filled into a nickel foam substrate. In this substrate an electrolytic oxidation reduction occurs in an alkaline solution containing lithium hydroxide.

Development of PVA based micro-porous polymer electrolyte by a novel preferential polymer dissolution process

NASA Astrophysics Data System (ADS)

Subramania, A.; Kalyana Sundaram, N. T.; Sukumar, N.

A micro-porous polymer electrolyte based on PVA was obtained from PVA-PVC based polymer blend film by a novel preferential polymer dissolution technique. The ionic conductivity of micro-porous polymer electrolyte increases with increase in the removal of PVC content. Finally, the effect of variation of lithium salt concentration is studied for micro-porous polymer electrolyte of high ionic conductivity composition. The ionic conductivity of the micro-porous polymer electrolyte is measured in the temperature range of 301-351 K. It is observed that a 2 M LiClO 4 solution of micro-porous polymer electrolyte has high ionic conductivity of 1.5055 × 10 -3 S cm -1 at ambient temperature. Complexation and surface morphology of the micro-porous polymer electrolytes are studied by X-ray diffraction and SEM analysis. TG/DTA analysis informs that the micro-porous polymer electrolyte is thermally stable upto 277.9 °C. Chronoamperommetry and linear sweep voltammetry studies were made to find out lithium transference number and stability of micro-porous polymer electrolyte membrane, respectively. Cyclic voltammetry study was performed for carbon/micro-porous polymer electrolyte/LiMn 2O 4 cell to reveal the compatibility and electrochemical stability between electrode materials.

Facile and scalable fabrication of polymer-ceramic composite electrolyte with high ceramic loadings

NASA Astrophysics Data System (ADS)

Pandian, Amaresh Samuthira; Chen, X. Chelsea; Chen, Jihua; Lokitz, Bradley S.; Ruther, Rose E.; Yang, Guang; Lou, Kun; Nanda, Jagjit; Delnick, Frank M.; Dudney, Nancy J.

2018-06-01

Solid state electrolytes are a promising alternative to flammable liquid electrolytes for high-energy lithium battery applications. In this work polymer-ceramic composite electrolyte membrane with high ceramic loading (greater than 60 vol%) is fabricated using a model polymer electrolyte poly(ethylene oxide) + lithium trifluoromethane sulfonate and a lithium-conducting ceramic powder. The effects of processing methods, choice of plasticizer and varying composition on ionic conductivity of the composite electrolyte are thoroughly investigated. The physical, structural and thermal properties of the composites are exhaustively characterized. We demonstrate that aqueous spray coating followed by hot pressing is a scalable and inexpensive technique to obtain composite membranes that are amazingly dense and uniform. The ionic conductivity of composites fabricated using this protocol is at least one order of magnitude higher than those made by dry milling and solution casting. The introduction of tetraethylene glycol dimethyl ether further increases the ionic conductivity. The composite electrolyte's interfacial compatibility with metallic lithium and good cyclability is verified by constructing lithium symmetrical cells. A remarkable Li+ transference number of 0.79 is discovered for the composite electrolyte.

Optimization of Pore Structure of Cathodic Carbon Supports for Solvate Ionic Liquid Electrolytes Based Lithium-Sulfur Batteries.

PubMed

Zhang, Shiguo; Ikoma, Ai; Li, Zhe; Ueno, Kazuhide; Ma, Xiaofeng; Dokko, Kaoru; Watanabe, Masayoshi

2016-10-04

Lithium-sulfur (Li-S) batteries are a promising energy-storage technology owing to their high theoretical capacity and energy density. However, their practical application remains a challenge because of the serve shuttle effect caused by the dissolution of polysulfides in common organic electrolytes. Polysulfide-insoluble electrolytes, such as solvate ionic liquids (ILs), have recently emerged as alternative candidates and shown great potential in suppressing the shuttle effect and improving the cycle stability of Li-S batteries. Redox electrochemical reactions in polysulfide-insoluble electrolytes occur via a solid-state process at the interphase between the electrolyte and the composite cathode; therefore, creating an appropriate interface between sulfur and a carbon support is of great importance. Nevertheless, the porous carbon supports established for conventional organic electrolytes may not be suitable for polysulfide-insoluble electrolytes. In this work, we investigated the effect of the porous structure of carbon materials on the Li-S battery performance in polysulfide-insoluble electrolytes using solvate ILs as a model electrolyte. We determined that the pore volume (rather than the surface area) exerts a major influence on the discharge capacity of S composite cathodes. In particular, inverse opal carbons with three-dimensionally ordered interconnected macropores and a large pore volume deliver the highest discharge capacity. The battery performance in both polysulfide-soluble electrolytes and solvate ILs was used to study the effect of electrolytes. We propose a plausible mechanism to explain the different porous structure requirements in polysulfide-soluble and polysulfide-insoluble electrolytes.

Stabilizing electrochemical interfaces in viscoelastic liquid electrolytes

PubMed Central

2018-01-01

Electrodeposition is a widely practiced method for creating metal, colloidal, and polymer coatings on conductive substrates. In the Newtonian liquid electrolytes typically used, the process is fundamentally unstable. The underlying instabilities have been linked to failure of microcircuits, dendrite formation on battery electrodes, and overlimiting conductance in ion-selective membranes. We report that viscoelastic electrolytes composed of semidilute solutions of very high–molecular weight neutral polymers suppress these instabilities by multiple mechanisms. The voltage window ΔV in which a liquid electrolyte can operate free of electroconvective instabilities is shown to be markedly extended in viscoelastic electrolytes and is a power-law function, ΔV : η1/4, of electrolyte viscosity, η. This power-law relation is replicated in the resistance to ion transport at liquid/solid interfaces. We discuss consequences of our observations and show that viscoelastic electrolytes enable stable electrodeposition of many metals, with the most profound effects observed for reactive metals, such as sodium and lithium. This finding is of contemporary interest for high-energy electrochemical energy storage. PMID:29582017

Electrolytic decontamination of conductive materials

NASA Astrophysics Data System (ADS)

Campbell, George M.; Nelson, Timothy O.; Parker, John L.; Getty, Richard H.; Hergert, Tom R.; Lindahl, Kirk A.; Peppers, Larry G.

1994-10-01

Using the electrolytic method, we have demonstrated removal of Pu and Am from contaminated conductive material. At EG and G /Rocky Flats, we electrolytically decontaminated stainless steel. Results from this work show removal of fixed contamination, including the following geometries: planar, large radius, bolt holes, glove ports, and protruding studs. More specifically, fixed contamination was reduced from levels ranging from greater than 1 000 000 counts per minute (cpm) down to levels ranging from 1500 to 250 cpm using the electrolytic method. More recently, the electrolytic work has continued at Los Alamos National Laboratory as a joint project with EG and G/Rocky Flats. Impressively, electrolytic decontamination of Pu /Am from U surfaces (10 sq cm per side) shows decreases in swipable contamination from 500 000-1 500 000 disintegrations per minute (dpm) down to 0-2 dpm. Moreover, the solid waste product of the electrolytic method is reduced in volume by more than 50 times compared with the liquid waste produced by the previous U decontamination method -- a hot concentrated acid spray leach process.

Micellar Electrolytes in Organic Electrochemical Transistors

NASA Astrophysics Data System (ADS)

Cicoira, Fabio; Giuseppe, Tarabella; Nanda, Gaurav; Iannotta, Salvatore; Santato, Clara

2012-02-01

Organic electrochemical transistors (OECTs) are promising for applications in sensing and bioelectronics. OECTs consist of a conducting polymer film (transistor channel) in contact with an electrolyte. A gate electrode immersed in the electrolyte controls the doping/dedoping level of the conducting polymer. OECTs can be operated in aqueous electrolytes, making possible the implementation of organic electronic materials at the interface with biology. The inherent signal amplification of OECTs has the potential to yield sensors with low detection limits and high sensitivity. In this talk we will present recent studies on OECTs using ionic surfactants (such as hexadecyl-trimethyl-ammonium bromide) as electrolytes. As the conducting polymer we used PEDOT:PSS, i.e. (Poly,3-4 ethylenedioxythiopene) doped with Poly(styrene sulphonate). Interestingly, ionic surfactant electrolytes result in large transistor current modulation, especially beyond the critical micellar concentration (CMC). Since micelles play a primary role in biological processes and drug-delivery systems, the use for micellar electrolytes opens new exciting opportunities for the use of OECTs in bioelectronics.

An air-stable Na 3SbS 4 superionic conductor prepared by a rapid and economic synthetic procedure

DOE PAGES

Wang, Hui; Chen, Yan; Hood, Zachary D.; ...

2016-01-01

All-solid-state sodium batteries, using abundant sodium resources and solid electrolyte, hold much promise for safe, low cost, large-scale energy storage. To realize the practical applications of all solid Na-ion batteries at ambient temperature, the solid electrolytes are required to have high ionic conductivity, chemical stability, and ideally, easy preparation. Ceramic electrolytes show higher ionic conductivity than polymers, but they often require extremely stringent synthesis conditions, either high sintering temperature above 1000 C or long-time, low-energy ball milling. Herein, we report a new synthesis route for Na 3SbS 4, a novel Na superionic conductor that needs much lower processing temperature belowmore » 200 C and easy operation. This new solid electrolyte exhibits a remarkable ionic conductivity of 1.05 mS cm -1 at 25 °C and is chemically stable under ambient atmosphere. In conclusion, this synthesis process provides unique insight into the current state-of-the-art solid electrolyte preparation and opens new possibilities for the design of similar materials.« less

Steel refining with an electrochemical cell

DOEpatents

Blander, M.; Cook, G.M.

1988-05-17

Apparatus is described for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom. 2 figs.

Steel refining with an electrochemical cell

DOEpatents

Blander, M.; Cook, G.M.

1985-05-21

Disclosed is an apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

Steel refining with an electrochemical cell

DOEpatents

Blander, Milton; Cook, Glenn M.

1988-01-01

Apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

Refractory lining for electrochemical cell

DOEpatents

Blander, Milton; Cook, Glenn M.

1987-01-01

Apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contcat with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

Membraneless laminar flow cell for electrocatalytic CO2 reduction with liquid product separation

NASA Astrophysics Data System (ADS)

Monroe, Morgan M.; Lobaccaro, Peter; Lum, Yanwei; Ager, Joel W.

2017-04-01

The production of liquid fuel products via electrochemical reduction of CO2 is a potential path to produce sustainable fuels. However, to be practical, a separation strategy is required to isolate the fuel-containing electrolyte produced at the cathode from the anode and also prevent the oxidation products (i.e. O2) from reaching the cathode. Ion-conducting membranes have been applied in CO2 reduction reactors to achieve this separation, but they represent an efficiency loss and can be permeable to some product species. An alternative membraneless approach is developed here to maintain product separation through the use of a laminar flow cell. Computational modelling shows that near-unity separation efficiencies are possible at current densities achievable now with metal cathodes via optimization of the spacing between the electrodes and the electrolyte flow rate. Laminar flow reactor prototypes were fabricated with a range of channel widths by 3D printing. CO2 reduction to formic acid on Sn electrodes was used as the liquid product forming reaction, and the separation efficiency for the dissolved product was evaluated with high performance liquid chromatography. Trends in product separation efficiency with channel width and flow rate were in qualitative agreement with the model, but the separation efficiency was lower, with a maximum value of 90% achieved.

ELECTROCHEMICAL DECONTAMINATION AND RECOVERY OF URANIUM VALUES

DOEpatents

McLaren, J.A.; Goode, J.H.

1958-05-13

An electrochemical process is described for separating uranium from fission products. The method comprises subjecting the mass of uranium to anodic dissolution in an electrolytic cell containing aqueous alkali bicarbonate solution as its electrolyte, thereby promoting a settling from the solution of a solid sludge from about the electrodes and separating the resulting electrolyte solution containing the anodically dissolved uranium from the sludge which contains the rare earth fission products.

Mechanisms for naphthalene removal during electrolytic aeration.

PubMed

Goel, Ramesh K; Flora, Joseph R V; Ferry, John

2003-02-01

Batch tests were performed to investigate chemical and physical processes that may result during electrolytic aeration of a contaminated aquifer using naphthalene as a model contaminant. Naphthalene degradation of 58-66% took place electrolytically and occurred at the same rates at a pH of 4 and 7. 1,4-naphthoquinone was identified as a product of the electrolysis. Stripping due to gases produced at the electrodes did not result in any naphthalene loss. Hydrogen peroxide (which may be produced at the cathode) did not have any effect on naphthalene, but the addition of ferrous iron (which may be present in aquifers) resulted in 67-99% disappearance of naphthalene. Chlorine (which may be produced from the anodic oxidation of chloride) can effectively degrade naphthalene at pH of 4, but not at a pH of 7. Mono-, di- and poly chloronaphthalenes were identified as oxidation products. Ferric iron coagulation (due to the oxidation of ferrous iron) did not significantly contribute to naphthalene loss. Overall, electrolytic oxidation and chemical oxidation due to the electrolytic by-products formed are significant abiotic processes that could occur and should be accounted for if bioremediation of PAH-contaminated sites via electrolytic aeration is considered. Possible undesirable products such as chlorinated compounds may be formed when significant amounts of chlorides are present.

Solvothermal synthesis of gallium-indium-zinc-oxide nanoparticles for electrolyte-gated transistors.

PubMed

Santos, Lídia; Nunes, Daniela; Calmeiro, Tomás; Branquinho, Rita; Salgueiro, Daniela; Barquinha, Pedro; Pereira, Luís; Martins, Rodrigo; Fortunato, Elvira

2015-01-14

Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium-indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 10(6), threshold voltage (VTh) of 0.3-1.9 V, and mobility up to 1 cm(2)/(V s), as a function of gallium-indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping.

In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhaoying; Zhang, Yanyan; Liu, Bingwen

The in situ molecular characterization of reaction intermediates and products at electrode-electrolyte interfaces is central to mechanistic studies of complex electrochemical processes, yet a great challenge. The coupling of electrochemistry (EC) and mass spectrometry (MS) has seen rapid development and found broad applicability in tackling challenges in analytical and bioanalytical chemistry. However, few truly in situ and real-time EC-MS studies have been reported at electrode-electrolyte interfaces. An innovative EC-MS coupling method named in situ liquid secondary ion mass spectrometry (SIMS) was recently developed by combining SIMS with a vacuum compatible microfluidic electrochemical device. Using this novel capability we report themore » first in situ elucidation of the electro-oxidation mechanism of a biologically significant organic compound, ascorbic acid (AA), at the electrode-electrolyte interface. The short-lived radical intermediate was successfully captured, which had not been detected directly before. Moreover, we demonstrated the power of this new technique in real-time monitoring of the formation and dynamic evolution of electrical double layers at the electrode-electrolyte interface. This work suggests further promising applications of in situ liquid SIMS in studying more complex chemical and biological events at the electrode-electrolyte interface.« less

Treatment of electrochemical cell components with lithium tetrachloroaluminate (LiAlCl.sub.4) to promote electrolyte wetting

DOEpatents

Eberhart, James G.; Battles, James E.

1980-01-01

Electrochemical cell components such as interelectrode separators, retaining screens and current collectors are contacted with lithium tetrachloroaluminate prior to contact with molten electrolytic salt to improve electrolyte wetting. The LiAlCl.sub.4 can be applied in powdered, molten or solution form but, since this material has a lower melting point than the electrolytic salt used in high-temperature cells, the powdered LiAlCl.sub.4 forms a molten flux prior to contact by the molten electrolyte when both materials are initially provided in solid form. Components of materials such as boron nitride and other materials which are difficult to wet with molten salts are advantageously treated by this process.

Operating a redox flow battery with a negative electrolyte imbalance

DOEpatents

Pham, Quoc; Chang, On; Durairaj, Sumitha

2015-03-31

Loss of flow battery electrode catalyst layers during self-discharge or charge reversal may be prevented by establishing and maintaining a negative electrolyte imbalance during at least parts of a flow battery's operation. Negative imbalance may be established and/or maintained actively, passively or both. Actively establishing a negative imbalance may involve detecting an imbalance that is less negative than a desired threshold, and processing one or both electrolytes until the imbalance reaches a desired negative level. Negative imbalance may be effectively established and maintained passively within a cell by constructing a cell with a negative electrode chamber that is larger than the cell's positive electrode chamber, thereby providing a larger quantity of negative electrolyte for reaction with positive electrolyte.

Investigation of grafted ETFE-based polymer membranes as alternative electrolyte for direct methanol fuel cells

NASA Astrophysics Data System (ADS)

Aricò, A. S.; Baglio, V.; Cretı̀, P.; Di Blasi, A.; Antonucci, V.; Brunea, J.; Chapotot, A.; Bozzi, A.; Schoemans, J.

Low cost ethylene-tetrafluoroethylene (ETFE)-based grafted membranes have been prepared by a process based on electron beam irradiation, subsequent grafting, cross-linking and sulfonation procedure. Two different grafted membranes varying by their grafting and cross-linking levels have been investigated for applications in direct methanol fuel cells (DMFCs) operating between 90 and 130 °C. DMFC assemblies based on these membranes showed cell resistance and performance values comparable to Nafion 117. Stable electrochemical performance was recorded during 1 month of cycled operation. Tailoring of grafting and cross-linking properties allows a significant reduction of methanol cross-over while maintaining suitable conductivity and performance levels.

A series of spinel phase cathode materials prepared by a simple hydrothermal process for rechargeable lithium batteries

NASA Astrophysics Data System (ADS)

Liang, Yan-Yu; Bao, Shu-Juan; Li, Hu-Lin

2006-07-01

A series of spinel-structured materials have been prepared by a simple hydrothermal procedure in an aqueous medium. The new synthetic method is time and energy saving i.e., no further thermal treatment and extended grinding. The main experimental process involved the insertion of lithium into electrolytic manganese dioxide with glucose as a mild reductant in an autoclave. Both the hydrothermal temperature and the presence of glucose play the critical roles in determining the final spinel integrity. Particular electrochemical performance has also been systematically explored, and the results show that Al 3+, F - co-substituted spinels have the best combination of initial capacity and capacity retention among all these samples, exhibited the initial capacity of 115 mAh/g and maintained more than 90% of the initial value at the 50th cycle.

Structural transformation of macroporous silicon anodes as a result of cyclic lithiation processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, G. V.; Kulova, T. L.; Tolmachev, V. A., E-mail: tva@mail.ioffe.ru

2013-09-15

Anodes based on a regular lattice of macroporous silicon with different periods, sizes, and shapes of pore cross sections are studied. The discharge capacity and its degradation during cycling (embedding and extraction of lithium) are examined. Scanning electron microscopy is used to analyze changes in the electrode structure upon the lithiation/delithiation of Si and to evaluate the elemental composition of the porous material. An ex situ morphological analysis of the electrodes demonstrates that, on the whole, the porous structure is preserved upon cycling and the thickness of silicon walls increases. The degree of Si-wall destruction depends on their initial thickness.more » Estimates show that the electrolyte reduction process mainly occurs according to the two-electron mechanism, with inorganic salts of lithium formed as a result.« less

The role of cathodic current in PEO of aluminum: Influence of cationic electrolyte composition on the transient current-voltage curves and the discharges optical emission spectra

NASA Astrophysics Data System (ADS)

Rogov, A. B.; Shayapov, V. R.

2017-02-01

In this paper, the influence of cationic electrolytes composition on electrical and optical responses of plasma electrolytic oxidation process of A1050 aluminum alloy under alternating polarization is considered. The electrolytes consist of 0.1 M boric acid with addition of one of the following hydroxides: LiOH, NaOH, KOH, tetraethylammonium hydroxide, Ca(OH)2 up to pH value 9.2. Coatings microstructure, elemental and phase compositions were studied by SEM, EDS and XRD. It was shown that the hysteresis of anodic current-voltage curve (specific feature of "Soft sparking" PEO) was clear observed in the presence of sodium and potassium cations. It was found that composition of microdischarges plasma is also affected by the nature of the cations. It was shown that there are a number of reciprocal processes, which take place under anodic and cathodic polarization.

Chloride supporting electrolytes for all-vanadium redox flow batteries.

PubMed

Kim, Soowhan; Vijayakumar, M; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Chen, Feng; Hu, Jianzhi; Li, Liyu; Yang, Zhenguo

2011-10-28

This paper examines vanadium chloride solutions as electrolytes for an all-vanadium redox flow battery. The chloride solutions were capable of dissolving more than 2.3 M vanadium at varied valence states and remained stable at 0-50 °C. The improved stability appeared due to the formation of a vanadium dinuclear [V(2)O(3)·4H(2)O](4+) or a dinuclear-chloro complex [V(2)O(3)Cl·3H(2)O](3+) in the solutions over a wide temperature range. The all-vanadium redox flow batteries with the chloride electrolytes demonstrated excellent reversibility and fairly high efficiencies. Only negligible, if any, gas evolution was observed. The improved energy capacity and good performance, along with the ease in heat management, would lead to substantial reduction in capital cost and life-cycle cost, making the vanadium chloride redox flow battery a promising candidate for stationary applications. This journal is © the Owner Societies 2011

Electro-catalytic oxidation device for removing carbon from a fuel reformate

DOEpatents

Liu, Di-Jia [Naperville, IL

2010-02-23

An electro-catalytic oxidation device (ECOD) for the removal of contaminates, preferably carbonaceous materials, from an influent comprising an ECOD anode, an ECOD cathode, and an ECOD electrolyte. The ECOD anode is at a temperature whereby the contaminate collects on the surface of the ECOD anode as a buildup. The ECOD anode is electrically connected to the ECOD cathode, which consumes the buildup producing electricity and carbon dioxide. The ECOD anode is porous and chemically active to the electro-catalytic oxidation of the contaminate. The ECOD cathode is exposed to oxygen, and made of a material which promotes the electro-chemical reduction of oxygen to oxidized ions. The ECOD electrolyte is non-permeable to gas, electrically insulating and a conductor to oxidized. The ECOD anode is connected to the fuel reformer and the fuel cell. The ECOD electrolyte is between and in ionic contact with the ECOD anode and the ECOD cathode.

The nature of interfacial instabilities in liquid metal batteries in a vertical magnetic field

NASA Astrophysics Data System (ADS)

Molokov, S.

2018-02-01

The nature of instabilities in liquid metal batteries in the presence of a vertical magnetic field has been studied. The battery consists of two liquid metal layers, connected to the collectors, and a layer with an electrolyte inbetween. The closed geometry in the horizontal plane has been replaced by a half-plane to get a better insight into the problem. As in aluminium reduction cells the instability is generated at the electrically insulating sidewall of the battery. A travelling-wave solution has been obtained, which shows that there are two modes of the instability, fast and slow. Either of these modes may be most unstable depending on the values of various parameters, the most important of which are the well-known parameter of the instability, β, and the density of the electrolyte. For the intermediate range of the electrolyte density the medium-size batteries may be expected to be stable.

Heat Acclimation and Water-Immersion Deconditioning: Fluid Electrolyte Shifts with Tilting

NASA Technical Reports Server (NTRS)

Conertino, V. A.; Shvartz, E.; Haines, R. F.; Bhattacharya, A.; Superinde, S. J.; Keil, L. C.; Greenlean, J. E.

1977-01-01

One of the major problems encountered by astronauts exposed to space flight is a reduction of orthostatic tolerance on return to earth. Many studies have been performed in an attempt to define the physiologic mechanism of orthostatic intolerance and to develop some remedial treatment. Exercise training does not appear to enhance orthostatic tolerance . In contrast, heat acclimation (i.e., exercise training in the heat) has been reported to enhance orthostatic tolerance. Since plasma volume increases with both exercise training and heat acclimation, it is not clear what role fluid and electrolytes play in determining tolerance to hydrostatic pressure. The purpose of this study was to compare the effects of exercise training in a cool environment and heat acclimation on resting plasma volume (PV) and the ensuing fluid and electrolyte shifts which occur during head-up tilting before and after water immersion deconditioning.

Glass cylindrical filter for electrolysis cell

NASA Astrophysics Data System (ADS)

Abe, Shinichi; Akiyama, Fuminori

1992-09-01

Some electrolysis requires separation of electrolytic solution by a filter between two electrodes in order to prevent products from reacting secondarily at another electrode. These filters are usually made of a glass filter or ion exchanger membrane, and they are fixed at the electrolysis cell or cover one electrode. This report presents a detachable glass cylindrical filter for electrolytic reaction. The glass cylindrical filter was made from glass filter powder placed in a mold and heated at 800 C for 18 minutes. Using this filter, electrolytic reduction of carbon dioxide was performed in 0 C hot water with benzoin. This reaction produces aqueous oil from carbon dioxide and water. The products were compared with and without the filter and, although the yield did not differ between the two reaction systems, products without the filter contained highly polymerized oil compared to those with the filter. This suggests that the aqueous oil was produced at the cathode and polymerized at the anode.

Anomalously enhanced hydration of aqueous electrolyte solution in hydrophobic carbon nanotubes to maintain stability.

PubMed

Ohba, Tomonori

2014-02-24

An understanding of the structure and behavior of electrolyte solutions in nanoenvironements is crucial not only for a wide variety of applications, but also for the development of physical, chemical, and biological processes. We demonstrate the structure and stability of electrolyte in carbon nanotubes using hybrid reverse Monte Carlo simulations of X-ray diffraction patterns. Hydrogen bonds between water are adequately formed in carbon nanotubes, although some hydrogen bonds are restricted by the interfaces of carbon nanotubes. The hydrogen bonding network of water in electrolyte in the carbon nanotubes is further weakened. On the other hand, formation of the ion hydration shell is significantly enhanced in the electrolyte in the carbon nanotubes in comparison to ion hydration in bulk electrolyte. The significant hydrogen bond and hydration shell formation are a result of gaining stability in the hydrophobic nanoenvironment. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemical performance of a solvent-free hybrid ceramic-polymer electrolyte based on Li7La3Zr2O12 in P(EO)15LiTFSI

NASA Astrophysics Data System (ADS)

Keller, Marlou; Appetecchi, Giovanni Battista; Kim, Guk-Tae; Sharova, Varvara; Schneider, Meike; Schuhmacher, Jörg; Roters, Andreas; Passerini, Stefano

2017-06-01

The preparation of hybrid ceramic-polymer electrolytes, consisting of 70 wt% of Li+ cation conducting Li7La3Zr2O12 (LLZO) and 30 wt% of P(EO)15LiTFSI polymer electrolyte, through a solvent-free procedure is reported. The LLZO-P(EO)15LiTFSI hybrid electrolytes exhibit remarkable improvement in terms of flexibility and processability with respect to pure LLZO ceramic electrolytes. The physicochemical and electrochemical investigation shows the effect of LLZO annealing, resulting in ion conduction gain. However, slow charge transfer at the ceramic-polymer interface is also observed especially at higher temperatures. Nevertheless, improved compatibility with lithium metal anodes and good Li stripping/plating behavior are exhibited by the LLZO-P(EO)15LiTFSI hybrid electrolytes with respect to P(EO)15LiTFSI.

Conversion of Carbon Dioxide into Ethanol by Electrochemical Synthesis Method Using Cu-Zn Electrode

NASA Astrophysics Data System (ADS)

Riyanto; Ramadan, S.; Fariduddin, S.; Aminudin, A. R.; Hayatri, A. K.

2018-01-01

Research on conversion of carbon dioxide into ethanol has been done. The conversion process is carried out in a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor. As cathode was used Cu-Zn, while as anode carbon was utilized. Variations of voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis were performed to determine the optimum conditions to convert carbon dioxide into ethanol. Sample of the electrochemical synthesis process was analyzed by gas chromatography. From the result, it is found that the optimum conditions of the electrochemical synthesis process of carbon dioxide conversion into ethanol are voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis are 3 volts, 0.4 M and 90 minutes with the ethanol concentration of 10.44%.

Copper recovery and cyanide oxidation by electrowinning from a spent copper-cyanide electroplating electrolyte.

PubMed

Dutra, A J B; Rocha, G P; Pombo, F R

2008-04-01

Copper-cyanide bleed streams arise from contaminated baths from industrial electroplating processes due to the buildup of impurities during continuous operation. These streams present an elevated concentration of carbonate, cyanide and copper, constituting a heavy hazard, which has to be treated for cyanide destruction and heavy metals removal, according to the local environmental laws. In the Brazilian Mint, bleed streams are treated with sodium hypochlorite, to destroy cyanide and precipitate copper hydroxide, a solid hazardous waste that has to be disposed properly in a landfill or treated for metal recovery. In this paper, a laboratory-scale electrolytic cell was developed to remove the copper from the bleed stream of the electroplating unit of the Brazilian Mint, permitting its reutilization in the plant and decreasing the amount of sludge to waste. Under favorable conditions copper recoveries around 99.9% were achieved, with an energy consumption of about 11 kWh/kg, after a 5-h electrolysis of a bath containing copper and total cyanide concentrations of 26 and 27 g/L, respectively. Additionally, a substantial reduction of the cyanide concentration was also achieved, decreasing the pollution load and final treatment costs.

Efficiently dense hierarchical graphene based aerogel electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Xin; Lu, Chengxing; Peng, Huifen; Zhang, Xin; Wang, Zhenkun; Wang, Gongkai

2016-08-01

Boosting gravimetric and volumetric capacitances simultaneously at a high rate is still a discrepancy in development of graphene based supercapacitors. We report the preparation of dense hierarchical graphene/activated carbon composite aerogels via a reduction induced self-assembly process coupled with a drying post treatment. The compact and porous structures of composite aerogels could be maintained. The drying post treatment has significant effects on increasing the packing density of aerogels. The introduced activated carbons play the key roles of spacers and bridges, mitigating the restacking of adjacent graphene nanosheets and connecting lateral and vertical graphene nanosheets, respectively. The optimized aerogel with a packing density of 0.67 g cm-3 could deliver maximum gravimetric and volumetric capacitances of 128.2 F g-1 and 85.9 F cm-3, respectively, at a current density of 1 A g-1 in aqueous electrolyte, showing no apparent degradation to the specific capacitance at a current density of 10 A g-1 after 20000 cycles. The corresponding gravimetric and volumetric capacitances of 116.6 F g-1 and 78.1 cm-3 with an acceptable cyclic stability are also achieved in ionic liquid electrolyte. The results show a feasible strategy of designing dense hierarchical graphene based aerogels for supercapacitors.

Electrochemical behavior and pH stability of artificial salivas for corrosion tests.

PubMed

Queiroz, Gláucia Maria Oliveira de; Silva, Leandro Freitas; Ferreira, José Tarcísio Lima; Gomes, José Antônio da Cunha P; Sathler, Lúcio

2007-01-01

It is assumed that the compositions of artificial salivas are similar to that of human saliva. However, the use of solutions with different compositions in in vitro corrosion studies can lead dissimilar electrolytes to exhibit dissimilar corrosivity and electrochemical stability. This study evaluated four artificial salivas as regards pH stability with time, redox potentials and the polarization response of an inert platinum electrode. The tested solutions were: SAGF medium, Mondelli artificial saliva, UFRJ artificial saliva (prepared at the School of Pharmacy, Federal University of Rio de Janeiro, RJ, Brazil) and USP-RP artificial saliva (prepared at the School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, SP, Brazil). It was observed that pH variations were less than 1 unit during a 50-hour test. The SAGF medium, and the UFRJ and USP-RP solutions exhibited more oxidizing characteristics, whereas the Mondelli solution presented reducing properties. Anodic polarization revealed oxidation of the evaluated electrolytes at potentials below +600 mV SCE. It was observed that the UFRJ and USP-RP solutions presented more intense oxidation and reduction processes as compared to the Mondelli and SAGF solutions.

In Situ-Grown ZnCo2O4 on Single-Walled Carbon Nanotubes as Air Electrode Materials for Rechargeable Lithium–Oxygen Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Bin; Xu, Wu; Yan, Pengfei

2015-10-12

Although lithium-oxygen (Li-O2) batteries have great potential to be used as one of the next generation energy storage systems due to their ultrahigh theoretical specific energy, there are still many significant barriers before their practical applications. These barriers include electrolyte and electrode instability, poor ORR/OER efficiency and cycling capability, etc. Development of a highly efficient catalyst will not only enhance ORR/OER efficiency, it may also improve the stability of electrolyte because the reduced charge voltage. Here we report the synthesis of nano-sheet-assembled ZnCo2O4 spheres/single walled carbon nanotubes (ZCO/SWCNTs) composites as high performance air electrode materials for Li-O2 batteries. The ZCOmore » catalyzed SWCNTs electrodes delivered high discharge capacities, decreased the onset of oxygen evolution reaction by 0.9 V during charge processes, and led to more stable cycling stability. These results indicate that ZCO/SWCNTs composite can be used as highly efficient air electrode for oxygen reduction and evolution reactions. The highly enhanced catalytic activity by uniformly dispersed ZnCo2O4 catalyst on nanostructured electrodes is expected to inspire« less

In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.

PubMed

Polovov, Ilya B; Volkovich, Vladimir A; Charnock, John M; Kralj, Brett; Lewin, Robert G; Kinoshita, Hajime; May, Iain; Sharrad, Clint A

2008-09-01

Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.

40 CFR 421.52 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORY Primary Electrolytic Copper Refining Subcategory § 421.52 Effluent limitations guidelines...,000 lb of product) Total suspended solids 0.100 0.050 Copper 0.0017 0.0008 Cadmium 0.00006 0.00003...

40 CFR 421.52 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORY Primary Electrolytic Copper Refining Subcategory § 421.52 Effluent limitations guidelines...,000 lb of product) Total suspended solids 0.100 0.050 Copper 0.0017 0.0008 Cadmium 0.00006 0.00003...

Rapid, cool sintering of wet processed yttria-stabilized zirconia ceramic electrolyte thin films.

PubMed

Park, Jun-Sik; Kim, Dug-Joong; Chung, Wan-Ho; Lim, Yonghyun; Kim, Hak-Sung; Kim, Young-Beom

2017-09-29

Here we report a photonic annealing process for yttria-stabilized zirconia films, which are one of the most well-known solid-state electrolytes for solid oxide fuel cells (SOFCs). Precursor films were coated using a wet-chemical method with a simple metal-organic precursor solution and directly annealed at standard pressure and temperature by two cycles of xenon flash lamp irradiation. The residual organics were almost completely decomposed in the first pre-annealing step, and the fluorite crystalline phases and good ionic conductivity were developed during the second annealing step. These films showed properties comparable to those of thermally annealed films. This process is much faster than conventional annealing processes (e.g. halogen furnaces); a few seconds compared to tens of hours, respectively. The significance of this work includes the treatment of solid-state electrolyte oxides for SOFCs and the demonstration of the feasibility of other oxide components for solid-state energy devices.

Ultramicroelectrode Studies of Self-Terminated Nickel Electrodeposition and Nickel Hydroxide Formation upon Water Reduction.

PubMed

Ritzert, Nicole L; Moffat, Thomas P

2016-12-08

The interaction between electrodeposition of Ni and electrolyte breakdown, namely the hydrogen evolution reaction (HER) via H 3 O + and H 2 O reduction, was investigated under well-defined mass transport conditions using ultramicroelectrodes (UME's) coupled with optical imaging, generation/collection scanning electrochemical microscopy (G/C-SECM), and preliminary microscale pH measurements. For 5 mmol/L NiCl 2 + 0.1 mol/L NaCl, pH 3.0, electrolytes, the voltammetric current at modest overpotentials, i.e. , between -0.6 V and -1.4 V vs. Ag/AgCl, was distributed between metal deposition and H 3 O + reduction, with both reactions reaching mass transport limited current values. At more negative potentials, an unusual sharp current spike appeared upon the onset of H 2 O reduction that was accompanied by a transient increase in H 2 production. The peak potential of the current spike was a function of both [Ni(H 2 O) 6 ] 2+ (aq) concentration and pH. The sharp rise in current was ascribed to the onset of autocatalytic H 2 O reduction, where electrochemically generated OH - species induce heterogeneous nucleation of Ni(OH) 2(ads) islands, the perimeter of which is reportedly active for H 2 O reduction. As the layer coalesces, further metal deposition is quenched while H 2 O reduction continues albeit at a decreased rate as fewer of the most reactive sites, e.g. , Ni/Ni(OH) 2 island edges, are available. At potentials below -1.5 V vs. Ag/AgCl, H 2 O reduction is accelerated, leading to homogeneous precipitation of bulk Ni(OH) 2 · x H 2 O within the nearly hemispherical diffusion layer of the UME.

A comparative study of quasi-solid nanoclay gel electrolyte and liquid electrolyte dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Main, Laura

Dye sensitized solar cells (DSSCs) are currently being explored as a cheaper alternative to the more common silicon (Si) solar cell technology. In addition to the cost advantages, DSSCs show good performance in low light conditions and are not sensitive to varying angles of incident light like traditional Si cells. One of the major challenges facing DSSCs is loss of the liquid electrolyte, through evaporation or leakage, which lowers stability and leads to increased degradation. Current research with solid-state and quasi-solid DSSCs has shown success regarding a reduction of electrolyte loss, but at a cost of lower conversion efficiency output. The research work presented in this paper focuses on the effects of using nanoclay material as a gelator in the electrolyte of the DSSC. The data showed that the quasi-solid cells are more stable than their liquid electrolyte counterparts, and achieved equal or better I-V characteristics. The quasi-solid cells were fabricated with a gel electrolyte that was prepared by adding 7 wt% of Nanoclay, Nanomer® (1.31PS, montmorillonite clay surface modified with 15-35% octadecylamine and 0.5-5 wt% aminopropyltriethoxysilane, Aldrich) to the iodide/triiodide liquid electrolyte, (Iodolyte AN-50, Solaronix). Various gel concentrations were tested in order to find the optimal ratio of nanoclay to liquid. The gel electrolyte made with 7 wt% nanoclay was more viscous, but still thin enough to allow injection with a standard syringe. Batches of cells were fabricated with both liquid and gel electrolyte and were evaluated at STC conditions (25°C, 100 mW/cm2) over time. The gel cells achieved efficiencies as high as 9.18% compared to the 9.65% achieved by the liquid cells. After 10 days, the liquid cell decreased to 1.75%, less than 20% of its maximum efficiency. By contrast, the gel cell's efficiency increased for two weeks, and did not decrease to 20% of maximum efficiency until 45 days. After several measurements, the liquid cells showed visible signs of leakage through the sealant, whereas the gel cells did not. This resistance to leakage likely contributed to the improved performance of the quasi-solid cells over time, and is a significant advantage over liquid electrolyte DSSCs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galvez-Aranda, Diego E.; Ponce, Victor; Seminario, Jorge M.

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. In this study, we performed molecular dynamics atomistic simulations to study the swelling, alloying, and amorphization of a silicon nanocrystal anode in a full nanobattery modelmore » 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 14Si 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. Also, 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 the solid electrolyte interphase in the anode.« less

Molecular dynamics simulations of the first charge of a Li-ion—Si-anode nanobattery

DOE PAGES

Galvez-Aranda, Diego E.; Ponce, Victor; Seminario, Jorge M.

2017-03-16

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. In this study, we performed molecular dynamics atomistic simulations to study the swelling, alloying, and amorphization of a silicon nanocrystal anode in a full nanobattery modelmore » 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 14Si 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. Also, 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 the solid electrolyte interphase in the anode.« less

Reclaiming the spent alkaline zinc manganese dioxide batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi0.5Mn1.5O4 materials.

PubMed

Ma, Ya; Cui, Yan; Zuo, Xiaoxi; Huang, Shanna; Hu, Keshui; Xiao, Xin; Nan, Junmin

2014-10-01

A process for reclaiming the materials in spent alkaline zinc manganese dioxide (Zn-Mn) batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi0.5Mn1.5O4 materials is presented. After dismantling battery cans, the iron cans, covers, electric rods, organic separator, label, sealing materials, and electrolyte are separated through the washing, magnetic separation, filtrating, and sieving operations. Then, the powder residues react with H2SO4 (2 mol L(-1)) solution to dissolve zinc under a liquid/solid ratio of 3:1 at room temperature, and subsequently, the electrolytic Zn with purity of ⩾99.8% is recovered in an electrolytic cell with a cathode efficiency of ⩾85% under the conditions of 37-40°C and 300 A m(-2). The most of MnO2 and a small quantity of electrolytic MnO2 are recovered from the filtration residue and the electrodeposit on the anode of electrolytic cell, respectively. The recovered manganese oxides are used to synthesize LiNi0.5Mn1.5O4 material of lithium-ion battery. The as-synthesized LiNi0.5Mn1.5O4 discharges 118.3 mAh g(-1) capacity and 4.7 V voltage plateau, which is comparable to the sample synthesized using commercial electrolytic MnO2. This process can recover the substances in the spent Zn-Mn batteries and innocuously treat the wastewaters, indicating that it is environmentally acceptable and applicable. Copyright © 2014 Elsevier Ltd. All rights reserved.

Primary and Secondary Lithium Batteries Capable of Operating at Low Temperatures for Planetary Exploration

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; West, W. C.; Brandon, E. J.

2011-01-01

Objectives and Approach: (1) Develop advanced Li ]ion electrolytes that enable cell operation over a wide temperature range (i.e., -60 to +60 C). Improve the high temperature stability and lifetime characteristics of wide operating temperature electrolytes. (2) Define the performance limitations at low and high temperature extremes, as well as, life limiting processes. (3) Demonstrate the performance of advanced electrolytes in large capacity prototype cells.

The role of ultra-thin SiO2 layers in metal-insulator-semiconductor (MIS) photoelectrochemical devices (Presentation Recording)

NASA Astrophysics Data System (ADS)

Esposito, Daniel V.

2015-08-01

Solid-state junctions based on a metal-insulator-semiconductor (MIS) architecture are of great interest for a number of optoelectronic applications such as photovoltaics, photoelectrochemical cells, and photodetection. One major advantage of the MIS junction compared to the closely related metal-semiconductor junction, or Schottky junction, is that the thin insulating layer (1-3 nm thick) that separates the metal and semiconductor can significantly reduce the density of undesirable interfacial mid-gap states. The reduction in mid-gap states helps "un-pin" the junction, allowing for significantly higher built-in-voltages to be achieved. A second major advantage of the MIS junction is that the thin insulating layer can also protect the underlying semiconductor from corrosion in an electrochemical environment, making the MIS architecture well-suited for application in (photo)electrochemical applications. In this presentation, discontinuous Si-based MIS junctions immersed in electrolyte are explored for use as i.) photoelectrodes for solar-water splitting in photoelectrochemical cells (PECs) and ii.) position-sensitive photodetectors. The development and optimization of MIS photoelectrodes for both of these applications relies heavily on understanding how processing of the thin SiO2 layer impacts the properties of nano- and micro-scale MIS junctions, as well as the interactions of the insulating layer with the electrolyte. In this work, we systematically explore the effects of insulator thickness, synthesis method, and chemical treatment on the photoelectrochemical and electrochemical properties of these MIS devices. It is shown that electrolyte-induced inversion plays a critical role in determining the charge carrier dynamics within the MIS photoelectrodes for both applications.

A Mössbauer spectral study of degradation in La 0.58Sr 0.4Fe 0.5Co 0.5O 3–x after long-term operation in solid oxide electrolysis cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahmoud, Abdelfattah; Daroukh, Mahmoud Al; Lipinska-Chwalek, Marta

Here, degradation processes of oxygen electrodes in solid oxide electrolysis cells (SOECs) were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Mössbauer spectroscopy. La 0.58Sr 0.4Fe 0.5Co 0.5O 3–x (LSCF) anodes (oxygen electrode) were analyzed after different long-term operations durations of 1774, 6100 and 9000 h. The results were compared with a cell in the initial state. Besides the LSCF anode, the SOECs were composed of a Ce 0.8Gd 0.2O 1.9 barrier layer between the anode and electrolyte, yttria-stabilized zirconia (YSZ) as electrolyte and Ni-YSZ as cathode (hydrogen electrode). Mössbauer spectra of the iron-containingmore » anode were acquired in order to determine the alteration of the iron oxidation state and its local environment during operation. Mössbauer spectroscopy yields indirect information about the degradation mechanism, especially in combination with SEM, TEM, and XRD. XRD and TEM revealed the appearance of Co 3O 4 during the SOEC operation and SEM analyses confirmed the formation of SrZrO 3 at the electrode/electrolyte interface. The spectral analysis confirmed the reduction of iron from Fe(IV) to Fe(III) in LSCF after long-term operation. The fraction of Fe(IV) in the electrode decreased with time and 18, 15, 13 and 11% were obtained for 0, 1774, 6100, and 9000 h of operation, respectively.« less

A Mössbauer spectral study of degradation in La 0.58Sr 0.4Fe 0.5Co 0.5O 3–x after long-term operation in solid oxide electrolysis cells

DOE PAGES

Mahmoud, Abdelfattah; Daroukh, Mahmoud Al; Lipinska-Chwalek, Marta; ...

2017-10-21

Here, degradation processes of oxygen electrodes in solid oxide electrolysis cells (SOECs) were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Mössbauer spectroscopy. La 0.58Sr 0.4Fe 0.5Co 0.5O 3–x (LSCF) anodes (oxygen electrode) were analyzed after different long-term operations durations of 1774, 6100 and 9000 h. The results were compared with a cell in the initial state. Besides the LSCF anode, the SOECs were composed of a Ce 0.8Gd 0.2O 1.9 barrier layer between the anode and electrolyte, yttria-stabilized zirconia (YSZ) as electrolyte and Ni-YSZ as cathode (hydrogen electrode). Mössbauer spectra of the iron-containingmore » anode were acquired in order to determine the alteration of the iron oxidation state and its local environment during operation. Mössbauer spectroscopy yields indirect information about the degradation mechanism, especially in combination with SEM, TEM, and XRD. XRD and TEM revealed the appearance of Co 3O 4 during the SOEC operation and SEM analyses confirmed the formation of SrZrO 3 at the electrode/electrolyte interface. The spectral analysis confirmed the reduction of iron from Fe(IV) to Fe(III) in LSCF after long-term operation. The fraction of Fe(IV) in the electrode decreased with time and 18, 15, 13 and 11% were obtained for 0, 1774, 6100, and 9000 h of operation, respectively.« less

Nanoclay gelation approach toward improved dye-sensitized solar cell efficiencies: an investigation of charge transport and shift in the TiO2 conduction band.

PubMed

Wang, Xiu; Kulkarni, Sneha A; Ito, Bruno Ieiri; Batabyal, Sudip K; Nonomura, Kazuteru; Wong, Chee Cheong; Grätzel, Michael; Mhaisalkar, Subodh G; Uchida, Satoshi

2013-01-23

Nanoclay minerals play a promising role as additives in the liquid electrolyte to form a gel electrolyte for quasi-solid-state dye-sensitized solar cells, because of the high chemical stability, unique swelling capability, ion exchange capacity, and rheological properties of nanoclays. Here, we report the improved performance of a quasi-solid-state gel electrolyte that is made from a liquid electrolyte and synthetic nitrate-hydrotalcite nanoclay. Charge transport mechanisms in the gel electrolyte and nanoclay interactions with TiO(2)/electrolyte interface are discussed in detail. The electrochemical analysis reveals that the charge transport is solely based on physical diffusion at the ratio of [PMII]:[I(2)] = 10:1 (where PMII is 1-propyl-3-methylimidazolium iodide). The calculated physical diffusion coefficient shows that the diffusion of redox ions is not affected much by the viscosity of nanoclay gel. The addition of nitrate-hydrotalcite clay in the electrolyte has the effect of buffering the protonation process at the TiO(2)/electrolyte interface, resulting in an upward shift in the conduction band and a boost in open-circuit voltage (V(OC)). Higher V(OC) values with undiminished photocurrent is achieved with nitrate-hydrotalcite nanoclay gel electrolyte for organic as well as for inorganic dye (D35 and N719) systems. The efficiency for hydrotalcite clay gel electrolyte solar cells is increased by 10%, compared to that of the liquid electrolyte. The power conversion efficiency can reach 10.1% under 0.25 sun and 9.6% under full sun. This study demonstrates that nitrate-hydrotalcite nanoclay in the electrolyte not only solidifies the liquid electrolyte to prevent solvent leakage, but also facilitates the improvement in cell efficiency.

Zinc-based electrolyte compositions, and related electrochemical processes and articles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kniajanski, Sergei; Soloveichik, Grigorii Lev

An aqueous electrolyte composition is described, including a zinc salt based on zinc acetate or zinc glocolate. The saturation concentration of zinc in the electrolyte composition is in the range of about 2.5M to about 3.5M. The composition also contains at least one salt of a monovalent cation. The molar ratio of zinc to the monovalent cation is about 1:2. An aqueous zinc electroplating bath, containing the aqueous electrolyte composition, is also disclosed, along with a method for the electrochemical deposition of zinc onto a substrate surface, using the electroplating bath. Related flow batteries are also described, including a catholyte,more » as well as an anolyte based on the aqueous electrolyte composition, with a membrane between the catholyte and the anolyte.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Junhua Jiang; Ted Aulich

An electrolytic renewable nitrogen fertilizer process that utilizes wind-generated electricity, N{sub 2} extracted from air, and syngas produced via the gasification of biomass to produce nitrogen fertilizer ammonia was developed at the University of North Dakota Energy & Environmental Research Center. This novel process provides an important way to directly utilize biosyngas generated mainly via the biomass gasification in place of the high-purity hydrogen which is required for Haber Bosch-based production of the fertilizer for the production of the widely used nitrogen fertilizers. Our preliminary economic projection shows that the economic competitiveness of the electrochemical nitrogen fertilizer process strongly dependsmore » upon the cost of hydrogen gas and the cost of electricity. It is therefore expected the cost of nitrogen fertilizer production could be considerably decreased owing to the direct use of cost-effective 'hydrogen-equivalent' biosyngas compared to the high-purity hydrogen. The technical feasibility of the electrolytic process has been proven via studying ammonia production using humidified carbon monoxide as the hydrogen-equivalent vs. the high-purity hydrogen. Process optimization efforts have been focused on the development of catalysts for ammonia formation, electrolytic membrane systems, and membrane-electrode assemblies. The status of the electrochemical ammonia process is characterized by a current efficiency of 43% using humidified carbon monoxide as a feedstock to the anode chamber and a current efficiency of 56% using high-purity hydrogen as the anode gas feedstock. Further optimization of the electrolytic process for higher current efficiency and decreased energy consumption is ongoing at the EERC.« less

Overhead Projector Demonstrations.

ERIC Educational Resources Information Center

Kolb, Doris, Ed.

1988-01-01

Provides two demonstrations: (1) electrolyte migration of ions using colored ions which cross a strip of gelatin allowing for noticeable migration; and (2) photochemical reduction of Fe+3 by the citrate ion. Points out both reactions can be done in a Petri dish using common lab materials. (MVL)

Characterization of stainless steel surface processed using electrolytic oxidation and titanium complex ion solution

NASA Astrophysics Data System (ADS)

Kang, Yubin; Choi, Jaeyoung; Park, Jinju; Kim, Woo-Byoung; Lee, Kun-Jae

2017-09-01

This study attempts to improve the physical and chemical adhesion between metals and ceramics by using electrolytic oxidation and a titanium organic/inorganic complex ion solution on the SS-304 plate. Surface analysis confirmed the existence of the Tisbnd Osbnd Mx bonds formed by the bonding between the metal ions and the Ti oxide at the surface of the pre-processed SS plate, and improved chemical adhesion during ceramic coating was expected by confirming the presence of the carboxylic group. The adhesion was evaluated by using the ceramic coating solution in order to assess the improved adhesion of the SS plate under conditions. The results showed that both the adhesion and durability were largely improved in the sample processed with all the pre-processing steps, thus confirming that the physical and chemical adhesion between metals and ceramics can be improved by enhancing the physical roughness via electrolytic oxidation and pre-processing using a Ti complex ion solution.

Surface Chemistry and Precursor Material Effects on the Performance of Pyrolyzed Nanofibers as Anodes for Lithium-ion Batteries

NASA Astrophysics Data System (ADS)

Loebl, Andrew James

Next-generation lithium-ion batteries to meet consumer demands and new applications require the development of new electrode materials. Electrospinning of polymers is a simple and effective method to create one-dimensional, self-supporting materials, with no inactive components after pyrolysis. Composites of these nanofibers and high-capacity lithium materials have been demonstrated to possess superior reversible capacity than state-of-the-art commercial anodes. Despite impressive reversible discharge capacities polyacrylonitrile-based composites are not ready for adoption in commercial applications. These materials suffer from irreversible losses of Li to formation on the electrode of the solid electrolyte interphase during the first charge of the cell. This thesis work has taken two approaches to engineer high-performing nanofiber-based electrodes. First, the chemistry at the interface of the electrode and the electrolyte has been changed by depositing new surfaces. Attempts to create a graphitic fiber surface via plasma enhanced chemical vapor deposition did not result in an improvement of the irreversible losses. However, the experiments did demonstrate the growth of large surface area carbon nanowalls on the pyrolyzed electrospun fibers, creating a material which could serve as a substrate in catalysis or as an electrode for composite ultra-capacitors. Additionally, passivation surfaces were deposited by atomic layer deposition and molecular layer deposition. These new surfaces were employed to reduce the irreversible consumption of lithium by moving the charge transfer reaction to the interface of the carbon and the new material. The removal the lithium from the solvent prior to charge transfer limits the irreversible reduction of solvent by metallic lithium. Alumina films grown by atomic layer deposition reduced lithium losses to the solid electrolyte interphase by up to 42% for twenty deposition cycles. This large improvement in irreversible capacity resulted in a nearly 50% reduction in reversible lithium storage. Thinner coatings of alumina had a less dramatic effect on both the irreversible capacity losses and the reversible discharge capacity. A coating of ten cycles of alumina at a temperature of 150 °C resulted in a 17% reduction in irreversible capacity with negligible impact on the reversible capacity. Hybrid aluminum-organic films grown by molecular layer deposition also reduced irreversible lithium losses. The largest reduction was 23% for electrodes coated with 40 cycles of the alucone material. For all thicknesses studied these hybrid films delivered less improvement than the alumina grown by atomic layer deposition, with poor reversible lithium storage capacity available at high charging and discharging currents. Second, polyacrylonitrile has served as the precursor for electrospun composite electrodes because of its ease of processing and well-known carbonization process. Polyimides represent a family of polymers for which the material properties can be tailored by careful monomer selection. These polymers were used as the non-woven matrix to create materials capable of delivering a larger percentage of their maximum reversible capacities at high currents when compared to polyacrylonitrile-based electrodes. These materials had a more graphitic structure based on Raman spectroscopy, and resulted in lower irreversible capacity losses than polyacrylonitrile-based fibers for fibers based on pyromellitic dianhydride and p-phenylene diamine.

Facile and scalable fabrication of polymer-ceramic composite electrolyte with high ceramic loadings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandian, Amaresh Samuthira; Chen, Xi Chelsea; Chen, Jihua

Solid state electrolytes are a promising alternative to flammable liquid electrolytes for high-energy lithium battery applications. In this work polymer-ceramic composite electrolyte membrane with high ceramic loading (greater than 60 vol%) is fabricated using a model polymer electrolyte poly(ethylene oxide) + lithium trifluoromethane sulfonate and a lithium-conducting ceramic powder. The effects of processing methods, choice of plasticizer and varying composition on ionic conductivity of the composite electrolyte are thoroughly investigated. The physical, structural and thermal properties of the composites are exhaustively characterized. We demonstrate that aqueous spray coating followed by hot pressing is a scalable and inexpensive technique to obtainmore » composite membranes that are amazingly dense and uniform. The ionic conductivity of composites fabricated using this protocol is at least one order of magnitude higher than those made by dry milling and solution casting. The introduction of tetraethylene glycol dimethyl ether further increases the ionic conductivity. The composite electrolyte's interfacial compatibility with metallic lithium and good cyclability is verified by constructing lithium symmetrical cells. As a result, a remarkable Li + transference number of 0.79 is discovered for the composite electrolyte.« less

Multi-layer thin-film electrolytes for metal supported solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Haydn, Markus; Ortner, Kai; Franco, Thomas; Uhlenbruck, Sven; Menzler, Norbert H.; Stöver, Detlev; Bräuer, Günter; Venskutonis, Andreas; Sigl, Lorenz S.; Buchkremer, Hans-Peter; Vaßen, Robert

2014-06-01

A key to the development of metal-supported solid oxide fuel cells (MSCs) is the manufacturing of gas-tight thin-film electrolytes, which separate the cathode from the anode. This paper focuses the electrolyte manufacturing on the basis of 8YSZ (8 mol.-% Y2O3 stabilized ZrO2). The electrolyte layers are applied by a physical vapor deposition (PVD) gas flow sputtering (GFS) process. The gas-tightness of the electrolyte is significantly improved when sequential oxidic and metallic thin-film multi-layers are deposited, which interrupt the columnar grain structure of single-layer electrolytes. Such electrolytes with two or eight oxide/metal layers and a total thickness of about 4 μm obtain leakage rates of less than 3 × 10-4 hPa dm3 s-1 cm-2 (Δp: 100 hPa) at room temperature and therefore fulfill the gas tightness requirements. They are also highly tolerant with respect to surface flaws and particulate impurities which can be present on the graded anode underground. MSC cell tests with double-layer and multilayer electrolytes feature high power densities more than 1.4 W cm-2 at 850 °C and underline the high potential of MSC cells.

Molecular interactions in high conductive gel electrolytes based on low molecular weight gelator.

PubMed

Bielejewski, Michał; Łapiński, Andrzej; Demchuk, Oleg

2017-03-15

Organic ionic gel (OIG) electrolytes, also known as gel electrolytes or ionogels are one example of modern functional materials with the potential to use in wide range of electrochemical applications. The functionality of OIGs arises from the thermally reversible solidification of electrolytes or ionic liquids and their superior ionic conductivity. To understand and to predict the properties of these systems it is important to get the knowledge about the interactions on molecular level between the solid gelator matrix and the electrolyte solution. This paper reports the spectroscopic studies (FT-IR, UV-Vis and Raman) of the gel electrolyte based on low molecular weight gelator methyl-4,6-O-(p-nitrobenzylidene)-α-d-glucopyranoside and solution of quaternary ammonium salt, tetramethylammonium bromide. The solidification process was based on sol-gel technique. Below characteristic temperature, defined as gel to sol phase transition temperature, T gs , the samples were solid-like and showed high conductivity values of the same order as observed for pure liquid electrolytes. The investigations were performed for a OIGs in a wide range of molar concentrations of the electrolyte solution. Copyright © 2016 Elsevier Inc. All rights reserved.

Highly Active Electrolytes for Rechargeable Mg Batteries Based on [Mg2(μ-Cl)2]2+ Cation Complex in Dimethoxyethane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Yingwen; Stolley, Ryan M.; Han, Kee Sung

2015-01-01

Highly active electrolytes based on a novel [Mg2(μ-Cl)2]2+ cation complex for reversible Mg deposition were developed and analyzed in this work. These electrolytes were formulated in dimethoxyethane through dehalodimerization of non-nucleophilic MgCl2 by reacting with either Mg salts (such as Mg(TFSI)2, TFSI= bis(trifluoromethane)sulfonylimide) or Lewis acid salts (such as AlEtCl2 or AlCl3). The cation complex was identified for the first time as [Mg2(μ-Cl)2(DME)4]2+ (DME=dimethoxyethane) and its molecular structure was characterized by single crystal X-ray diffraction, Raman spectroscopy and NMR. The electrolyte synthesis process was studied and rational approaches for formulating highly active electrolytes were proposed. Through control of the anions,more » electrolytes with efficiency close to 100%, wide electrochemical window (up to 3.5V) and high ionic conductivity (> 6 mS/cm) were obtained. The electrolyte synthesis and understandings developed in this work could bring significant opportunities for rational formulation of electrolytes with the general formula [Mg2(μ-Cl)2(DME)4][anion]x for practical Mg batteries.« less

Facile and scalable fabrication of polymer-ceramic composite electrolyte with high ceramic loadings

DOE PAGES

Pandian, Amaresh Samuthira; Chen, Xi Chelsea; Chen, Jihua; ...

2018-04-24

Solid state electrolytes are a promising alternative to flammable liquid electrolytes for high-energy lithium battery applications. In this work polymer-ceramic composite electrolyte membrane with high ceramic loading (greater than 60 vol%) is fabricated using a model polymer electrolyte poly(ethylene oxide) + lithium trifluoromethane sulfonate and a lithium-conducting ceramic powder. The effects of processing methods, choice of plasticizer and varying composition on ionic conductivity of the composite electrolyte are thoroughly investigated. The physical, structural and thermal properties of the composites are exhaustively characterized. We demonstrate that aqueous spray coating followed by hot pressing is a scalable and inexpensive technique to obtainmore » composite membranes that are amazingly dense and uniform. The ionic conductivity of composites fabricated using this protocol is at least one order of magnitude higher than those made by dry milling and solution casting. The introduction of tetraethylene glycol dimethyl ether further increases the ionic conductivity. The composite electrolyte's interfacial compatibility with metallic lithium and good cyclability is verified by constructing lithium symmetrical cells. As a result, a remarkable Li + transference number of 0.79 is discovered for the composite electrolyte.« less

Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

NASA Astrophysics Data System (ADS)

Qin, Ya

Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have about twice the exchange current density of composite SSC-LSGMC/LSGMC interfaces at 700°C. In this research effort, it has been found that: (1) the glycine-nitrate combustion process is favorable to produce perovskite-type oxide powders with good phase purity and negligible intermediate or contaminant phases; (2) The electrochemical performance for both the SSC-LSGMC and LSCF-LSGMC composite electrode materials on LSGMC confirm their potential for use in intermediate temperature SOFC applications; (3) The composite LSCF-LSGMC electrode exhibited much higher current density than the composite SSC-LSGMC electrode in the current dc polarization measurements; and (4) Primary market study results showed promising commercialization feasibility of these new materials sets, provided production is scaled up (with dramatic cost reductions).

Improved Electrolytic Hydrogen Peroxide Generator

NASA Technical Reports Server (NTRS)

James, Patrick I.

2005-01-01

An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

Buried anode lithium thin film battery and process for forming the same

DOEpatents

Lee, Se-Hee; Tracy, C. Edwin; Liu, Ping

2004-10-19

A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

Process for electrolytic deposition of metals on zirconium materials

DOEpatents

Donaghy, Robert E.

1979-01-30

A process for the electrolytic deposition of a metal layer on an article comprised of zirconium or a zirconium alloy is disclosed. The article is activated in an aged aqueous solution comprising from about 10 to about 20 grams per liter ammonium bifluoride and from about 0.75 to about 2 grams per liter of sulfuric acid. The solution is aged by immersion of pickled zirconium in the solution for at least about 10 minutes. The loosely adhering film formed on the article in the activating step is removed and the article is contacted with an electrolytic plating solution containing the metal to be deposited on the article in the presence of an electrode receiving current.

High-Performance All-Solid-State Na-S Battery Enabled by Casting-Annealing Technology.

PubMed

Fan, Xiulin; Yue, Jie; Han, Fudong; Chen, Ji; Deng, Tao; Zhou, Xiuquan; Hou, Singyuk; Wang, Chunsheng

2018-04-24

Room-temperature all-solid-state Na-S batteries (ASNSBs) using sulfide solid electrolytes are a promising next-generation battery technology due to the high energy, enhanced safety, and earth abundant resources of both sodium and sulfur. Currently, the sulfide electrolyte ASNSBs are fabricated by a simple cold-pressing process leaving with high residential stress. Even worse, the large volume change of S/Na 2 S during charge/discharge cycles induces additional stress, seriously weakening the less-contacted interfaces among the solid electrolyte, active materials, and the electron conductive agent that are formed in the cold-pressing process. The high and continuous increase of the interface resistance hindered its practical application. Herein, we significantly reduce the interface resistance and eliminate the residential stress in Na 2 S cathodes by fabricating Na 2 S-Na 3 PS 4 -CMK-3 nanocomposites using melting-casting followed by stress-release annealing-precipitation process. The casting-annealing process guarantees the close contact between the Na 3 PS 4 solid electrolyte and the CMK-3 mesoporous carbon in mixed ionic/electronic conductive matrix, while the in situ precipitated Na 2 S active species from the solid electrolyte during the annealing process guarantees the interfacial contact among these three subcomponents without residential stress, which greatly reduces the interfacial resistance and enhances the electrochemical performance. The in situ synthesized Na 2 S-Na 3 PS 4 -CMK-3 composite cathode delivers a stable and highly reversible capacity of 810 mAh/g at 50 mA/g for 50 cycles at 60 °C. The present casting-annealing strategy should provide opportunities for the advancement of mechanically robust and high-performance next-generation ASNSBs.

Impact of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Reaction Activity for Platinum Electrocatalysts

DOE PAGES

Christ, J. M.; Neyerlin, K. C.; Wang, H.; ...

2014-10-30

The impact of model membrane degradation compounds on the relevant electrochemical parameters for the oxygen reduction reaction (i.e. electrochemical surface area and catalytic activity), was studied for both polycrystalline Pt and carbon supported Pt electrocatalysts. Model compounds, representing previously published, experimentally determined polymer electrolyte membrane degradation products, were in the form of perfluorinated organic acids that contained combinations of carboxylic and/or sulfonic acid functionality. Perfluorinated carboxylic acids of carbon chain length C1 – C6 were found to have an impact on electrochemical surface area (ECA). The longest chain length acid also hindered the observed oxygen reduction reaction (ORR) performance, resultingmore » in a 17% loss in kinetic current (determined at 0.9 V). Model compounds containing sulfonic acid functional groups alone did not show an effect on Pt ECA or ORR activity. Lastly, greater than a 44% loss in ORR activity at 0.9V was observed for diacid model compounds DA-Naf (perfluoro(2-methyl-3-oxa-5-sulfonic pentanoic) acid) and DA-3M (perfluoro(4-sulfonic butanoic) acid), which contained both sulfonic and carboxylic acid functionalities.« less

An anion-immobilized composite electrolyte for dendrite-free lithium metal anodes

PubMed Central

Zhao, Chen-Zi; Zhang, Xue-Qiang; Cheng, Xin-Bing; Zhang, Rui; Xu, Rui; Chen, Peng-Yu; Peng, Hong-Jie; Huang, Jia-Qi

2017-01-01

Lithium metal is strongly regarded as a promising electrode material in next-generation rechargeable batteries due to its extremely high theoretical specific capacity and lowest reduction potential. However, the safety issue and short lifespan induced by uncontrolled dendrite growth have hindered the practical applications of lithium metal anodes. Hence, we propose a flexible anion-immobilized ceramic–polymer composite electrolyte to inhibit lithium dendrites and construct safe batteries. Anions in the composite electrolyte are tethered by a polymer matrix and ceramic fillers, inducing a uniform distribution of space charges and lithium ions that contributes to a dendrite-free lithium deposition. The dissociation of anions and lithium ions also helps to reduce the polymer crystallinity, rendering stable and fast transportation of lithium ions. Ceramic fillers in the electrolyte extend the electrochemically stable window to as wide as 5.5 V and provide a barrier to short circuiting for realizing safe batteries at elevated temperature. The anion-immobilized electrolyte can be applied in all–solid-state batteries and exhibits a small polarization of 15 mV. Cooperated with LiFePO4 and LiNi0.5Co0.2Mn0.3O2 cathodes, the all–solid-state lithium metal batteries render excellent specific capacities of above 150 mAh⋅g−1 and well withstand mechanical bending. These results reveal a promising opportunity for safe and flexible next-generation lithium metal batteries. PMID:28973945

Enhanced electrochemical performance of in situ reduced graphene oxide-polyaniline nanotubes hybrid nanocomposites using redox-additive aqueous electrolyte

NASA Astrophysics Data System (ADS)

Devi, Madhabi; Kumar, A.

2018-02-01

Reduced graphene oxide (RGO)-polyaniline nanotubes (PAniNTs) nanocomposites have been synthesized by in situ reduction of GO. The morphology and structure of the nanocomposites are characterized by HRTEM, XRD and micro-Raman spectroscopy. The electrical and electrochemical performances of the nanocomposites are investigated for different RGO concentrations by conductivity measurements, cyclic voltammetry, charge-discharge and electrochemical impedance spectroscopy. Highest gravimetric specific capacitance of 448.71 F g-1 is obtained for 40 wt.% of RGO-PAniNTs nanocomposite as compared to 194.92 F g-1 for pure PAniNTs in 1 M KCl electrolyte. To further improve the electrochemical performance of the nanocomposite electrode, KI is used as redox-additive with 1 M KCl electrolyte. Highest gravimetric specific capacitance of 876.43 F g-1 and an improved cyclic stability of 91% as compared to 79% without KI after 5000 cycles is achieved for an optimized 0.1 M KI concentration. This is attributed to the presence of different ionic species of I- ions that give rise to a number of possible redox reactions improving the pseudocapacitance of the electrode. This improved capacitive performance is compared with that of catechol redox-additive in 1 M KCl electrolyte, and that of KI and catechol redox-additives added to 1 M H2SO4 electrolyte.

Self-diffusion of electrolyte species in model battery electrodes using Magic Angle Spinning and Pulsed Field Gradient Nuclear Magnetic Resonance

NASA Astrophysics Data System (ADS)

Tambio, Sacris Jeru; Deschamps, Michaël; Sarou-Kanian, Vincent; Etiemble, Aurélien; Douillard, Thierry; Maire, Eric; Lestriez, Bernard

2017-09-01

Lithium-ion batteries are electrochemical storage devices using the electrochemical activity of the lithium ion in relation to intercalation compounds owing to mass transport phenomena through diffusion. Diffusion of the lithium ion in the electrode pores has been poorly understood due to the lack of experimental techniques for measuring its self-diffusion coefficient in porous media. Magic-Angle Spinning, Pulsed Field Gradient, Stimulated-Echo Nuclear Magnetic Resonance (MAS-PFG-STE NMR) was used here for the first time to measure the self-diffusion coefficients of the electrolyte species in the LP30 battery electrolyte (i.e. a 1 M solution of LiPF6 dissolved in 1:1 Ethylene Carbonate - Dimethyl Carbonate) in model composites. These composite electrodes were made of alumina, carbon black and PVdF-HFP. Alumina's magnetic susceptibility is close to the measured magnetic susceptibility of the LP30 electrolyte thereby limiting undesirable internal field gradients. Interestingly, the self-diffusion coefficient of lithium ions decreases with increasing carbon content. FIB-SEM was used to describe the 3D geometry of the samples. The comparison between the reduction of self-diffusion coefficients as measured by PFG-NMR and as geometrically derived from FIB/SEM tortuosity values highlights the contribution of specific interactions at the material/electrolyte interface on the lithium transport properties.

Direct printing and reduction of graphite oxide for flexible supercapacitors

NASA Astrophysics Data System (ADS)

Jung, Hanyung; Ve Cheah, Chang; Jeong, Namjo; Lee, Junghoon

2014-08-01

We report direct printing and photo-thermal reduction of graphite oxide (GO) to obtain a highly porous pattern of interdigitated electrodes, leading to a supercapacitor on a flexible substrate. Key parameters optimized include the amount of GO delivered, the suitable photo-thermal energy level for effective flash reduction, and the substrate properties for appropriate adhesion after reduction. Tests with supercapacitors based on the printed-reduced GO showed performance comparable with commercial supercapacitors: the energy densities were 1.06 and 0.87 mWh/cm3 in ionic and organic electrolytes, respectively. The versatility in the architecture and choice of substrate makes this material promising for smart power applications.

Electrolytic lesions of the nucleus accumbens enhance locomotor sensitization to nicotine in rats.

PubMed

Kelsey, John E; Willmore, Ellen J

2006-06-01

Electrolytic lesions of the medial core of the nucleus accumbens (NAc) in male Long-Evans rats increased spontaneous locomotion, enhanced the locomotor stimulating effect of acute 5.0 mg/kg cocaine, enhanced the development and subsequent expression of locomotor sensitization produced by repeated injections of 0.4 mg/kg nicotine but not 7.5 mg/kg cocaine, and enhanced the expression of conditioned locomotion. Given that 6-hydroxydopamine lesions of the NAc typically have effects on locomotor-related processes that are opposite of those produced by electrolytic and excitotoxic lesions, these data are consistent with a hypothesis that the NAc output, especially from the core, inhibits a variety of such processes and that the DA input to the NAc enhances these processes by inhibiting this inhibitory output. Copyright 2006 APA, all rights reserved.

Influence of supporting electrolyte in electricity generation and degradation of organic pollutants in photocatalytic fuel cell.

PubMed

Khalik, Wan Fadhilah; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Voon, Chun-Hong; Yusuf, Sara Yasina; Yusoff, Nik Athirah; Lee, Sin-Li

2016-08-01

This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in degradation of Reactive Black 5 (RB5) and generation of electricity. Zinc oxide (ZnO) was immobilized onto carbon felt acted as photoanode, while Pt-coated carbon paper as photocathode was placed in a single chamber photocatalytic fuel cell, which then irradiated by UV lamp for 24 h. The degradation and mineralization of RB5 with 0.1 M NaCl rapidly decreased after 24-h irradiation time, followed by MgSO4, Na2SO4 and without electrolyte. The voltage outputs for Na2SO4, MgSO4 and NaCl were 908, 628 and 523 mV, respectively, after 24-h irradiation time; meanwhile, their short-circuit current density, J SC, was 1.3, 1.2 and 1.05 mA cm(-2), respectively. The power densities for Na2SO4, MgSO4 and NaCl were 0.335, 0.256 and 0.245 mW cm(-2), respectively. On the other hand, for without supporting electrolyte, the voltage output and short-circuit current density was 271.6 mV and 0.055 mA cm(-2), respectively. The supporting electrolyte NaCl showed greater performance in degradation of RB5 and generation of electricity due to the formation of superoxide radical anions which enhance the degradation of dye. The mineralization of RB5 with different supporting electrolyte was measured through spectrum analysis and reduction in COD concentration.

Durability of the Li 1+xTi 2–xAl x(PO 4) 3 Solid Electrolyte in Lithium–Sulfur Batteries

DOE PAGES

Wang, Shaofei; Ding, Yu; Zhou, Guangmin; ...

2016-10-31

Adoption of cells with a solid-state electrolyte is a promising solution for eliminating the polysulfide shuttle problem in Li-S batteries. Among the various known lithium-ion conducting solid electrolytes, the sodium superionic conductor (NASICON)-type Li 1+xTi 2-xAl x(PO 4) 3 offers the advantage of good stability under ambient conditions and in contact with air. Accordingly, we present here a comprehensive assessment of the durability of Li 1+xTi 2-xAl x(PO 4) 3 in contact with polysulfide solution and in Li-S cells. Because of its high reduction potential (2.5 V vs Li/Li +), Li 1+xTi 2-xAl x(PO 4) 3 gets lithiated in contactmore » with lithium polysulfide solution and Li 2CO 3 is formed on the particle surface, blocking the interfacial lithium-ion transport between the liquid and solid-state electrolytes. After the lithium insertion into the NASICON framework, the crystal expands in an anisotropic way, weakening the crystal bonds, causing fissures and resultant cracks in the ceramic, corroding the grain boundaries by polysulfide solution, and leaving unfavorable pores. The assembly of pores creates a gateway for polysulfide diffusion from the cathode side to the anode side, causing an abrupt decline in cell performance. Therefore, the solid-state electrolytes need to have good chemical compatibility with both the electrode and electrolyte, long-term stability under harsh chemical environment, and highly stable grain boundaries.« less

Molten salt bath circulation design for an electrolytic cell

DOEpatents

Dawless, R.K.; LaCamera, A.F.; Troup, R.L.; Ray, S.P.; Hosler, R.B.

1999-08-17

An electrolytic cell for reduction of a metal oxide to a metal and oxygen has an inert anode and an upwardly angled roof covering the inert mode. The angled roof diverts oxygen bubbles into an upcomer channel, thereby agitating a molten salt bath in the upcomer channel and improving dissolution of a metal oxide in the molten salt bath. The molten salt bath has a lower velocity adjacent the inert anode in order to minimize corrosion by substances in the bath. A particularly preferred cell produces aluminum by electrolysis of alumina in a molten salt bath containing aluminum fluoride and sodium fluoride. 4 figs.

Communication — Modeling polymer-electrolyte fuel-cell agglomerates with double-trap kinetics

DOE PAGES

Pant, Lalit M.; Weber, Adam Z.

2017-04-14

A new semi-analytical agglomerate model is presented for polymer-electrolyte fuel-cell cathodes. The model uses double-trap kinetics for the oxygen-reduction reaction, which can capture the observed potential-dependent coverage and Tafel-slope changes. An iterative semi-analytical approach is used to obtain reaction rate constants from the double-trap kinetics, oxygen concentration at the agglomerate surface, and overall agglomerate reaction rate. The analytical method can predict reaction rates within 2% of the numerically simulated values for a wide range of oxygen concentrations, overpotentials, and agglomerate sizes, while saving simulation time compared to a fully numerical approach.

STRIPPING PROCESS FOR PLUTONIUM

DOEpatents

Kolodney, M.

1959-10-01

A method for removing silver, nickel, cadmium, zinc, and indium coatings from plutonium objects while simultaneously rendering the plutonium object passive is described. The coated plutonium object is immersed as the anode in an electrolyte in which the plutonium is passive and the coating metal is not passive, using as a cathode a metal which does not dissolve rapidly in the electrolyte. and passing an electrical current through the electrolyte until the coating metal is removed from the plutonium body.

Gex-Model Using Local Area Fraction for Binary Electrolyte Systems

NASA Astrophysics Data System (ADS)

Haghtalab, Ali; Joda, Marzieh

2007-06-01

The correlation and prediction of phase equilibria of electrolyte systems are essential in the design and operation of many industrial processes such as downstream processing in biotechnology, desalination, hydrometallurgy, etc. In this research, the local composition non-random two liquid-nonrandom factor (NRTL-NRF) model of Haghtalab and Vera was extended for uni-univalent aqueous electrolyte solutions. Based on the assumptions of the NRTL-NRF model, excess Gibbs free energy ( g E) functions were derived for binary electrolyte systems. In this work, the local area fraction was applied and the modified model of NRTL-NRF was developed with either an equal or unequal surface area of an anion to the surface area of a cation. The modified NRTL-NRF models consist of two contributions, one due to long-range forces represented by the Debye-Hückel theory, and the other due to short-range forces, represented by local area fractions of species through nonrandom factors. Each model contains only two adjustable parameters per electrolyte. In addition, the model with unequal surface area of ionic species gives better results in comparison with the second new model with equal surface area of ions. The results for the mean activity coefficients for aqueous solutions of uni-univalent electrolytes at 298.15 K showed that the present model is more accurate than the original NRTL-NRF model.

Carboxymethylcellulose adsorption on molybdenite: the effect of electrolyte composition on adsorption, bubble-surface collisions, and flotation.

PubMed

Kor, Mohammad; Korczyk, Piotr M; Addai-Mensah, Jonas; Krasowska, Marta; Beattie, David A

2014-10-14

The adsorption of carboxymethylcellulose polymers on molybdenite was studied using spectroscopic ellipsometry and atomic force microscopy imaging with two polymers of differing degrees of carboxyl group substitution and at three different electrolyte conditions: 1 × 10(-2) M KCl, 2.76 × 10(-2) M KCl, and simulated flotation process water of multicomponent electrolyte content, with an ionic strength close to 2.76 × 10(-2) M. A higher degree of carboxyl substitution in the adsorbing polymer resulted in adsorbed layers that were thinner and with more patchy coverage; increasing the ionic strength of the electrolyte resulted in increased polymer layer thickness and coverage. The use of simulated process water resulted in the largest layer thickness and coverage for both polymers. The effect of the adsorbed polymer layer on bubble-particle attachment was studied with single bubble-surface collision experiments recorded with high-speed video capture and image processing and also with single mineral molybdenite flotation tests. The carboxymethylcellulose polymer with a lower degree of substitution resulted in almost complete prevention of wetting film rupture at the molybdenite surface under all electrolyte conditions. The polymer with a higher degree of substitution prevented rupture only when adsorbed from simulated process water. Molecular kinetic theory was used to quantify the effect of the polymer on the dewetting dynamics for collisions that resulted in wetting film rupture. Flotation experiments confirmed that adsorbed polymer layer properties, through their effect on the dynamics of bubble-particle attachment, are critical to predicting the effectiveness of polymers used to prevent mineral recovery in flotation.

Surface and interface sciences of Li-ion batteries. -Research progress in electrode-electrolyte interface-

NASA Astrophysics Data System (ADS)

Minato, Taketoshi; Abe, Takeshi

2017-12-01

The application potential of Li-ion batteries is growing as demand increases in different fields at various stages in energy systems, in addition to their conventional role as power sources for portable devices. In particular, applications in electric vehicles and renewable energy storage are increasing for Li-ion batteries. For these applications, improvements in battery performance are necessary. The Li-ion battery produces and stores electric power from the electrochemical redox reactions between the electrode materials. The interface between the electrodes and electrolyte strongly affects the battery performance because the charge transfer causing the electrode redox reaction begins at this interface. Understanding of the surface structure, electronic structure, and chemical reactions at the electrode-electrolyte interface is necessary to improve battery performance. However, the interface is located between the electrode and electrolyte materials, hindering the experimental analysis of the interface; thus, the physical properties and chemical processes have remained poorly understood until recently. Investigations of the physical properties and chemical processes at the interface have been performed using advanced surface science techniques. In this review, current knowledge and future research prospects regarding the electrode-electrolyte interface are described for the further development of Li-ion batteries.

MODELING THE ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE IN A GRANULAR GRAPHITE-PACKED REACTOR

EPA Science Inventory

A comprehensive reactor model was developed for the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite cathode. The reactor model describes the dynamic processes of TCE dechlorination and adsorption, and the formation and dechlorination of all the major...

40 CFR 421.56 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Electrolytic Copper.... The mass of wastewater pollutants in primary electrolytic copper refining process wastewater... pounds) of copper cast Arsenic .692 .309 Copper .638 .304 Nickel .274 .184 (b) Subpart E—Anode and...

40 CFR 421.56 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Electrolytic Copper.... The mass of wastewater pollutants in primary electrolytic copper refining process wastewater... pounds) of copper cast Arsenic .692 .309 Copper .638 .304 Nickel .274 .184 (b) Subpart E—Anode and...

[Adverse effects of drugs in intensive care units: analysis of the administration of electrolyte solutions and antibiotics].

PubMed

Manenti, S; Chaves, A B; Leopoldino, R S; Padilha, K G

1998-12-01

The aims of this study were: 1) to verify the incidence of adverse occurrences (AOs) with medication related to the time of electrolyte solutions infusion and the frequency of doses of antibiotics prescribed and administered to the patients; 2) to characterize the nature of those occurrences. The study was developed in two ICUs of a general hospital of São Paulo City. The population was composed by 51 patients that were in the ICUs in August of 1996. Sixty percent of the patients were older than 60 years, 58.8% were women, 49.1% remained in ICU from 1 to 4 days and 41.2% went to the Intermediate Care Units after ICU. Regarding the incidence of AOs related to the time of administration of the electrolyte solutions and the frequency of doses of antibiotics the non execution of the patient's medical prescriptions was verified in 76.3% and 38.8% respectively. The largest frequency of irregularities with the electrolyte solutions (60.2%) was the infusion faster than the prescribed time followed by the reduction of the number of doses of antibiotics administered. Taking these into consideration we have to invest in preventive measures to reduce those occurrences.

Critical evaluation of the stability of highly concentrated LiTFSI - Acetonitrile electrolytes vs. graphite, lithium metal and LiFePO4 electrodes

NASA Astrophysics Data System (ADS)

Nilsson, Viktor; Younesi, Reza; Brandell, Daniel; Edström, Kristina; Johansson, Patrik

2018-04-01

Highly concentrated LiTFSI - acetonitrile electrolytes have recently been shown to stabilize graphite electrodes in lithium-ion batteries (LIBs) much better than comparable more dilute systems. Here we revisit this system in order to optimise the salt concentration vs. both graphite and lithium metal electrodes with respect to electrochemical stability. However, we observe an instability regardless of concentration, making lithium metal unsuitable as a counter electrode, and this also affects evaluation of e.g. graphite electrodes. While the highly concentrated electrolytes have much improved electrochemical stabilities, their reductive decomposition below ca. 1.2 V vs. Li+/Li° still makes them less practical vs. graphite electrodes, and the oxidative reaction with Al at ca. 4.1 V vs. Li+/Li° makes them problematic for high voltage LIB cells. The former originates in an insufficiently stable solid electrolyte interphase (SEI) dissolving and continuously reforming - causing self-discharge, as observed by paused galvanostatic cycling, while the latter is likely caused by aluminium current collector corrosion. Yet, we show that medium voltage LiFePO4 positive electrodes can successfully be used as counter and reference electrodes.

Designing solid-liquid interphases for sodium batteries.

PubMed

Choudhury, Snehashis; Wei, Shuya; Ozhabes, Yalcin; Gunceler, Deniz; Zachman, Michael J; Tu, Zhengyuan; Shin, Jung Hwan; Nath, Pooja; Agrawal, Akanksha; Kourkoutis, Lena F; Arias, Tomas A; Archer, Lynden A

2017-10-12

Secondary batteries based on earth-abundant sodium metal anodes are desirable for both stationary and portable electrical energy storage. Room-temperature sodium metal batteries are impractical today because morphological instability during recharge drives rough, dendritic electrodeposition. Chemical instability of liquid electrolytes also leads to premature cell failure as a result of parasitic reactions with the anode. Here we use joint density-functional theoretical analysis to show that the surface diffusion barrier for sodium ion transport is a sensitive function of the chemistry of solid-electrolyte interphase. In particular, we find that a sodium bromide interphase presents an exceptionally low energy barrier to ion transport, comparable to that of metallic magnesium. We evaluate this prediction by means of electrochemical measurements and direct visualization studies. These experiments reveal an approximately three-fold reduction in activation energy for ion transport at a sodium bromide interphase. Direct visualization of sodium electrodeposition confirms large improvements in stability of sodium deposition at sodium bromide-rich interphases.The chemistry at the interface between electrolyte and electrode plays a critical role in determining battery performance. Here, the authors show that a NaBr enriched solid-electrolyte interphase can lower the surface diffusion barrier for sodium ions, enabling stable electrodeposition.