Multiphysics Modelling of Sodium Sulfur Battery

Science.gov (United States)

Mason, Jerry Hunter

Due to global climate change and the desire to decrease greenhouse gas emissions, large scale energy storage has become a critical issue. Renewable energy sources such as wind and solar will not be a viable energy source unless the storage problem is solved. One of the practical and cost effective solutions for this problem is sodium sulfur batteries. These batteries are comprised of liquid electrode materials suspended in porous media and operate at relatively high temperatures (>300°C). The sodium anode and the sulfur/sodium-polysulfide cathode are separated by a solid electrolyte made of beta-alumina or NASICON material. Due to the use of porous materials in the electrodes, capillary pressure and the combination of capillary action and gravity become important. Capillary pressure has a strong dependence on the wetting phase (liquid electrode material) saturation; therefore sharp concentration gradients can occur between the inert gas and the electrode liquid, especially within the cathode. These concentration gradients can have direct impacts on the electrodynamics of the battery as they may produce areas of high electrical potential variation, which can decrease efficiency and even cause failures. Then, thermal management also becomes vital since the electrochemistry and material properties are sensitive to temperature gradients. To investigate these phenomena in detail and to attempt to improve upon battery design a multi-dimensional, multi-phase code has been developed and validated in this study. Then a porous media flow model is implemented. Transport equations for charge, mass and heat are solved in a time marching fashion using finite volume method. Material properties are calculated and updated as a function of time. The porous media model is coupled with the continuity equation and a separate diffusion equation for the liquid sodium in the melt. The total mass transport model is coupled with charge transport via Faraday's law. Results show that

Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries.

Science.gov (United States)

He, Jianjiang; Wang, Ning; Cui, Zili; Du, Huiping; Fu, Lin; Huang, Changshui; Yang, Ze; Shen, Xiangyan; Yi, Yuanping; Tu, Zeyi; Li, Yuliang

2017-10-27

Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g -1 for lithium ion batteries and 650 mAh g -1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

High sulfur content polymer nanoparticles obtained from interfacial polymerization of sodium polysulfide and 1,2,3-trichloropropane in water.

Science.gov (United States)

Lim, Jeewoo; Jung, Unho; Joe, Won Tae; Kim, Eui Tae; Pyun, Jeffrey; Char, Kookheon

2015-06-01

Sulfur-rich materials have recently attracted keen interest for their potentials in optical, electrochemical, and pesticidal applications as well as their utility in dynamic covalent bond chemistry. Many sulfur-rich polymers, however, are insoluble and processing methods are therefore very limited. The synthesis and characterization of water-dispersible polymer nanoparticles (NPs) with the sulfur content exceeding 75% by weight, obtained from the interfacial polymerization between 1,2,3-trichloropropane and sodium polysulfide in water is reported here. The interfacial polymerization yields well-defined sulfur-rich NPs in the presence of surfactants, which are capable of serving a dual role as a phase transfer catalyst on top of emulsifiers. Such dual role allows for the control of the product NP size by varying its concentration. The surfactants can be easily removed by centrifugation and redispersion in water is also reported here. The resulting sulfur-rich NPs are characterized through elemental analysis, dynamic light scattering, ζ-potential measurements, and scanning electron microscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

Science.gov (United States)

Ding, Changsheng; Nohira, Toshiyuki; Hagiwara, Rika

2018-06-01

The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g-1 at a current rate of 10 mA g-1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

The corrosion behavior of molybdenum and Hastelloy B in sulfur and sodium polysulfides at 623 K

International Nuclear Information System (INIS)

Brown, A.P.

1987-01-01

An experimental study was completed to determine the corrosion behavior of molybdenum and Hastelloy B, a nickel-based alloy with high molybdenum content, in sulfur and sodium polysulfides (Na/sub 2/S/sub 3/,Na/sub 2/S/sub 4/, Na/sub 2/S/sub 5/) at 623 K. In sulfur, molybdenum corrodes very slowly, with a parabolic rate constant of 3.6 x 10/sup -9/ cm s/sup -1/2/. Hastelloy B shows no measurable corrosion after 100h of exposure to sulfur. The corrosion reaction of molybdenum in Na/sub 2/S/sub 3/ is characterized by the formation of a protective film that effectively eliminates further corrosion after the first 100h of exposure. Hastelloy B, however, corrodes rapidly in Na/sub 2/S/sub 3/, with corrosion rates approaching those of pure nickel under the same conditions. After the first 4h of exposure, the kinetics for the corrosion of Hastelloy B in Na/sub 2/S/sub 3/ follows a linear rate law. The scale morphology has multiple spalled layers of NiS/sub 2/, with some crystallites of NiS/sub 2/ appearing on the leading face of the scale and between the individual scale layers. This spalling causes smaller coupons of the Hastelloy B to corrode faster than larger coupons

Nickel Hexacyanoferrate Nanoparticle Electrodes For Aqueous Sodium and Potassium Ion Batteries

KAUST Repository

Wessells, Colin D.; Peddada, Sandeep V.; Huggins, Robert A.; Cui, Yi

2011-01-01

needed for grid-scale storage pose substantial challenges for conventional battery technology.(1, 2)Here, we demonstrate insertion/extraction of sodium and potassium ions in a low-strain nickel hexacyanoferrate electrode material for at least five

Mechanical properties of multi-walled carbon nanotube/epoxy polysulfide nanocomposite

International Nuclear Information System (INIS)

Shirkavand Hadavand, Behzad; Mahdavi Javid, Kimya; Gharagozlou, Mehrnaz

2013-01-01

Highlights: ► Preparation of epoxy polysulfide nanocomposite. ► Multi-walled carbon nanotubes have been modified and dispersed in epoxy polysulfide matrix. ► Mechanical properties of MWNT/epoxy polysulfide have been studied. - Abstract: In this research, multi-walled carbon nanotubes (MWCNTs) were modified by acid functionalization (H 2 SO 4 :HNO 3 = 1:3 by volume) and then mechanical properties of reinforced epoxy polysulfide resin by the both pure and treated MWNTs have been evaluated. For achieving this goal, different weight percentages of pure and treated MWCNT (0.1–0.3 wt%) were dispersed in the epoxy polysulfide resin separately and then mixed with curing agent. Experimental results have shown significant difference between acid treated and untreated MWCNTs in mechanical properties of epoxy polysulfide nanocomposites. In nanocomposite with 0.1–0.3% acid treated MWCNTs we observed increase of Young’s modulus from 458 to 723 MPa, tensile strength from 5.29 to 8.83 MPa and fracture strain from 0.16% to 0.25%. For understanding the structure and morphology of nanocomposite, the dispersion states were studied using scanning electron microscopy (SEM) and field emission electron microscopy (FESEM). The results showed better dispersion of modified carbon nanotube than unmodified in polymeric matrix

Balancing surface adsorption and diffusion of lithium-polysulfides on nonconductive oxides for lithium-sulfur battery design.

Science.gov (United States)

Tao, Xinyong; Wang, Jianguo; Liu, Chong; Wang, Haotian; Yao, Hongbin; Zheng, Guangyuan; Seh, Zhi Wei; Cai, Qiuxia; Li, Weiyang; Zhou, Guangmin; Zu, Chenxi; Cui, Yi

2016-04-05

Lithium-sulfur batteries have attracted attention due to their six-fold specific energy compared with conventional lithium-ion batteries. Dissolution of lithium polysulfides, volume expansion of sulfur and uncontrollable deposition of lithium sulfide are three of the main challenges for this technology. State-of-the-art sulfur cathodes based on metal-oxide nanostructures can suppress the shuttle-effect and enable controlled lithium sulfide deposition. However, a clear mechanistic understanding and corresponding selection criteria for the oxides are still lacking. Herein, various nonconductive metal-oxide nanoparticle-decorated carbon flakes are synthesized via a facile biotemplating method. The cathodes based on magnesium oxide, cerium oxide and lanthanum oxide show enhanced cycling performance. Adsorption experiments and theoretical calculations reveal that polysulfide capture by the oxides is via monolayered chemisorption. Moreover, we show that better surface diffusion leads to higher deposition efficiency of sulfide species on electrodes. Hence, oxide selection is proposed to balance optimization between sulfide-adsorption and diffusion on the oxides.

Balancing surface adsorption and diffusion of lithium-polysulfides on nonconductive oxides for lithium–sulfur battery design

Science.gov (United States)

Tao, Xinyong; Wang, Jianguo; Liu, Chong; Wang, Haotian; Yao, Hongbin; Zheng, Guangyuan; Seh, Zhi Wei; Cai, Qiuxia; Li, Weiyang; Zhou, Guangmin; Zu, Chenxi; Cui, Yi

2016-01-01

Lithium–sulfur batteries have attracted attention due to their six-fold specific energy compared with conventional lithium-ion batteries. Dissolution of lithium polysulfides, volume expansion of sulfur and uncontrollable deposition of lithium sulfide are three of the main challenges for this technology. State-of-the-art sulfur cathodes based on metal-oxide nanostructures can suppress the shuttle-effect and enable controlled lithium sulfide deposition. However, a clear mechanistic understanding and corresponding selection criteria for the oxides are still lacking. Herein, various nonconductive metal-oxide nanoparticle-decorated carbon flakes are synthesized via a facile biotemplating method. The cathodes based on magnesium oxide, cerium oxide and lanthanum oxide show enhanced cycling performance. Adsorption experiments and theoretical calculations reveal that polysulfide capture by the oxides is via monolayered chemisorption. Moreover, we show that better surface diffusion leads to higher deposition efficiency of sulfide species on electrodes. Hence, oxide selection is proposed to balance optimization between sulfide-adsorption and diffusion on the oxides. PMID:27046216

A highly efficient polysulfide mediator for lithium-sulfur batteries

Science.gov (United States)

Liang, Xiao; Hart, Connor; Pang, Quan; Garsuch, Arnd; Weiss, Thomas; Nazar, Linda F.

2015-01-01

The lithium-sulfur battery is receiving intense interest because its theoretical energy density exceeds that of lithium-ion batteries at much lower cost, but practical applications are still hindered by capacity decay caused by the polysulfide shuttle. Here we report a strategy to entrap polysulfides in the cathode that relies on a chemical process, whereby a host—manganese dioxide nanosheets serve as the prototype—reacts with initially formed lithium polysulfides to form surface-bound intermediates. These function as a redox shuttle to catenate and bind ‘higher’ polysulfides, and convert them on reduction to insoluble lithium sulfide via disproportionation. The sulfur/manganese dioxide nanosheet composite with 75 wt% sulfur exhibits a reversible capacity of 1,300 mA h g-1 at moderate rates and a fade rate over 2,000 cycles of 0.036%/cycle, among the best reported to date. We furthermore show that this mechanism extends to graphene oxide and suggest it can be employed more widely.

Polysulfide intercalated layered double hydroxides for metal capture applications

Energy Technology Data Exchange (ETDEWEB)

Kanatzidis, Mercouri G.; Ma, Shulan

2017-04-04

Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

Powering Lithium-Sulfur Battery Performance by Propelling Polysulfide Redox at Sulfiphilic Hosts.

Science.gov (United States)

Yuan, Zhe; Peng, Hong-Jie; Hou, Ting-Zheng; Huang, Jia-Qi; Chen, Cheng-Meng; Wang, Dai-Wei; Cheng, Xin-Bing; Wei, Fei; Zhang, Qiang

2016-01-13

Lithium-sulfur (Li-S) battery system is endowed with tremendous energy density, resulting from the complex sulfur electrochemistry involving multielectron redox reactions and phase transformations. Originated from the slow redox kinetics of polysulfide intermediates, the flood of polysulfides in the batteries during cycling induced low sulfur utilization, severe polarization, low energy efficiency, deteriorated polysulfide shuttle, and short cycling life. Herein, sulfiphilic cobalt disulfide (CoS2) was incorporated into carbon/sulfur cathodes, introducing strong interaction between lithium polysulfides and CoS2 under working conditions. The interfaces between CoS2 and electrolyte served as strong adsorption and activation sites for polar polysulfides and therefore accelerated redox reactions of polysulfides. The high polysulfide reactivity not only guaranteed effective polarization mitigation and promoted energy efficiency by 10% but also promised high discharge capacity and stable cycling performance during 2000 cycles. A slow capacity decay rate of 0.034%/cycle at 2.0 C and a high initial capacity of 1368 mAh g(-1) at 0.5 C were achieved. Since the propelling redox reaction is not limited to Li-S system, we foresee the reported strategy herein can be applied in other high-power devices through the systems with controllable redox reactions.

Chemical Immobilization Effect on Lithium Polysulfides for Lithium-Sulfur Batteries.

Science.gov (United States)

Li, Caixia; Xi, Zhucong; Guo, Dexiang; Chen, Xiangju; Yin, Longwei

2018-01-01

Despite great progress in lithium-sulfur batteries (LSBs), great obstacles still exist to achieve high loading content of sulfur and avoid the loss of active materials due to the dissolution of the intermediate polysulfide products in the electrolyte. Relationships between the intrinsic properties of nanostructured hosts and electrochemical performance of LSBs, especially, the chemical interaction effects on immobilizing polysulfides for LSB cathodes, are discussed in this Review. Moreover, the principle of rational microstructure design for LSB cathode materials with strong chemical interaction adsorbent effects on polysulfides, such as metallic compounds, metal particles, organic polymers, and heteroatom-doped carbon, is mainly described. According to the chemical immobilizing mechanism of polysulfide on LSB cathodes, three kinds of chemical immobilizing effects, including the strong chemical affinity between polar host and polar polysulfides, the chemical bonding effect between sulfur and the special function groups/atoms, and the catalytic effect on electrochemical reaction kinetics, are thoroughly reviewed. To improve the electrochemical performance and long cycling life-cycle stability of LSBs, possible solutions and strategies with respect to the rational design of the microstructure of LSB cathodes are comprehensively analyzed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polysulfide coordination clusters of the lanthanides

Energy Technology Data Exchange (ETDEWEB)

Ma, Ying-Zhao; Bestgen, Sebastian; Gamer, Michael T.; Roesky, Peter W. [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Konchenko, Sergey N. [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk (Russian Federation); Novosibirsk State University (Russian Federation)

2017-10-16

The reaction of [(DippForm){sub 2}Ln(thf){sub 2}] with an excess of elemental sulfur in toluene resulted in the formation of the trinuclear polysulfide coordination clusters [(DippForm){sub 3}Ln{sub 3}S{sub 12}] (Ln=Sm, Yb; DippForm=N,N'-bis(2,6-diisopropylphenyl)formamidinate). These are the first f element coordination clusters (Ln{sub n}S{sub x}) with a larger polysulfide unit (n and x>2). The formation of the coordination clusters can be rationalized by the reductive cleavage of S{sub 8} with divalent lanthanides. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Characterization of Lithium Polysulfide Salts in Homopolymers and Block Copolymers

Science.gov (United States)

Wang, Dunyang; Wujcik, Kevin; Balsara, Nitash

Ion-conducting polymers are important for solid-state batteries due to the promise of better safety and the potential to produce higher energy density batteries. Nanostructured block copolymer electrolytes can provide high ionic conductivity and mechanical strength through microphase separation. One of the potential use of block copolymer electrolytes is in lithium-sulfur batteries, a system that has high theoretical energy density wherein the reduction of sulfur leads to the formation of lithium polysulfide intermediates. In this study we investigate the effect of block copolymer morphology on the speciation and transport properties of the polysulfides. The morphology and conductivities of polystyrene-b-poly(ethylene oxide) (SEO) containing lithium polysulfides were studies using small-angle X-ray scattering and ac impedance spectroscopy. UV-vis spectroscopy is being used to determine nature of the polysulfide species in poly(ethylene oxide) and SEO. Department of Energy, Soft Matter Electron Microscopy Program and Battery Materials Research Program.

Nano-hydroxyapatite as an Efficient Polysulfide Absorbent for High-performance Li-S Batteries

International Nuclear Information System (INIS)

Liu, Naiqiang; Ai, Fei; Wang, Weikun; Shao, Hongyuan; Zhang, Hao; Wang, Anbang; Xu, Zhichuan J.; Huang, Yaqin

2016-01-01

Highlights: • Nano-HA has been demonstrated as an efficient polysulfide absorbent. • The shuttle effect of polysulfide in Li-S battery has been confined by the nano-HA. • Nano-HA used as additive improved electrochemical performance of Li-S battery. - Abstract: Lithium-sulfur (Li-S) battery is regarded as one of the most promising candidates for developing advanced energy storage system, but the polysulfide shuttle effect remains the biggest obstacle for its practical application. In this work, nano-hydroxyapatite (Ca 5 (PO 4 ) 3 (OH)) was used as an additive in the sulfur cathode and carbon-coated separator to prevent the polysulfide shuttle effect and thus to achieve the high performance. The sulfur cathode with nano-hydroxyapatite exhibited a higher reversible capacity and a more stable cycling performance than that of the pristine sulfur cathode. The improved capacity retention from 58% (100th) to 73% (200th) after introducing nano-hydroxyapatite into the sulfur cathode confirmed its strong polysulfide absorption ability. Furthermore, a nano-hydroxyapatite modified separator was developed to suppress the polysulfide shuttle effect and to facilitate the reutilization of sulfur species. The nano-hydroxyapatite particles served as polysulfide absorbents to bind polysulfides and suppress their diffusion to the anode. The batteries assembled with this separator exhibited a high reversible capacity of 886 mAhg −1 at 0.1C and 718 mAh g −1 at 0.5C after 200 cycles, with a low capacity fading of ∼0.10-0.11% per-cycle. At the highest sulfur loading of 4.5 mg cm −2 used for practical applications, the reversible areal capacity was much higher than the areal capacity (4 mAh cm −2 ) of commercial lithium-ion batteries. Therefore, the strategy using nano-hydroxyapatite as polysulfide absorbent shows great potential for solving the polysulfide shuttle problem and developing high performance Li-S batteries.

Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium

International Nuclear Information System (INIS)

Afkhami, Abbas; Bahiraei, Atousa; Madrakian, Tayyebeh

2016-01-01

A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03–200 μmol L −1 . The lower detection limits were found to be 0.02 μmol L −1 . The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility. - Highlights: • GCE was modified with multiwalled carbon nanotube and gold nanoparticles. • AuNP/MWCNT/GCE was used for the determination of diclofenac sodium. • Modified electrode was characterized by SEM, EDS and EIS. • The proposed method showed excellent analytical figures of merit. • This sensor was used for the determination of diclofenac sodium in real samples.

Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium

Energy Technology Data Exchange (ETDEWEB)

Afkhami, Abbas, E-mail: afkhami@basu.ac.ir; Bahiraei, Atousa; Madrakian, Tayyebeh

2016-02-01

A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03–200 μmol L{sup −1}. The lower detection limits were found to be 0.02 μmol L{sup −1}. The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility. - Highlights: • GCE was modified with multiwalled carbon nanotube and gold nanoparticles. • AuNP/MWCNT/GCE was used for the determination of diclofenac sodium. • Modified electrode was characterized by SEM, EDS and EIS. • The proposed method showed excellent analytical figures of merit. • This sensor was used for the determination of diclofenac sodium in real samples.

Direct observation of lithium polysulfides in lithium-sulfur batteries using operando X-ray diffraction

Science.gov (United States)

Conder, Joanna; Bouchet, Renaud; Trabesinger, Sigita; Marino, Cyril; Gubler, Lorenz; Villevieille, Claire

2017-06-01

In the on going quest towards lithium-battery chemistries beyond the lithium-ion technology, the lithium-sulfur system is emerging as one of the most promising candidates. The major outstanding challenge on the route to commercialization is controlling the so-called polysulfide shuttle, which is responsible for the poor cycling efficiency of the current generation of lithium-sulfur batteries. However, the mechanistic understanding of the reactions underlying the polysulfide shuttle is still incomplete. Here we report the direct observation of lithium polysulfides in a lithium-sulfur cell during operation by means of operando X-ray diffraction. We identify signatures of polysulfides adsorbed on the surface of a glass-fibre separator and monitor their evolution during cycling. Furthermore, we demonstrate that the adsorption of the polysulfides onto SiO2 can be harnessed for buffering the polysulfide redox shuttle. The use of fumed silica as an electrolyte additive therefore significantly improves the specific charge and Coulombic efficiency of lithium-sulfur batteries.

Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium.

Science.gov (United States)

Afkhami, Abbas; Bahiraei, Atousa; Madrakian, Tayyebeh

2016-02-01

A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03-200μmolL(-1). The lower detection limits were found to be 0.02μmolL(-1). The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility. Copyright © 2015 Elsevier B.V. All rights reserved.

Use of polysulfides of alkali and alkaline-earth metals to obtain highly dispersed sulfur

International Nuclear Information System (INIS)

Massalimov, I.A.; Vikhareva, I.N.; Kireeva, M.S.

2008-01-01

Possibilities of obtaining polysulfides of alkali and alkaline earth metals (M is Na, K, Ca, Sr, Ba) in aqueous solutions were considered. The composition of the polysulfides and their concentration in solutions were found. The efficiencies of application of highly dispersed sulfur, produced from calcium polysulfide, and colloid sulfur as a fungicide were compared [ru

Chloride-Reinforced Carbon Nanofiber Host as Effective Polysulfide Traps in Lithium-Sulfur Batteries.

Science.gov (United States)

Fan, Lei; Zhuang, Houlong L; Zhang, Kaihang; Cooper, Valentino R; Li, Qi; Lu, Yingying

2016-12-01

Lithium-sulfur (Li-S) battery is one of the most promising alternatives for the current state-of-the-art lithium-ion batteries due to its high theoretical energy density and low production cost from the use of sulfur. However, the commercialization of Li-S batteries has been so far limited to the cyclability and the retention of active sulfur materials. Using co-electrospinning and physical vapor deposition procedures, we created a class of chloride-carbon nanofiber composites, and studied their effectiveness on polysulfides sequestration. By trapping sulfur reduction products in the modified cathode through both chemical and physical confinements, these chloride-coated cathodes are shown to remarkably suppress the polysulfide dissolution and shuttling between lithium and sulfur electrodes. From adsorption experiments and theoretical calculations, it is shown that not only the sulfide-adsorption effect but also the diffusivity in the vicinity of these chlorides materials plays an important role on the reversibility of sulfur-based cathode upon repeated cycles. Balancing the adsorption and diffusion effects of these nonconductive materials could lead to the enhanced cycling performance of an Li-S cell. Electrochemical analyses over hundreds of cycles indicate that cells containing indium chloride-modified carbon nanofiber outperform cells with other halogenated salts, delivering an average specific capacity of above 1200 mAh g -1 at 0.2 C.

Hg/HgO electrode and hydrogen evolution potentials in aqueous sodium hydroxide

Energy Technology Data Exchange (ETDEWEB)

Nickell, Ryan A.; Zhu, Wenhua H.; Payne, Robert U.; Cahela, Donald R.; Tatarchuk, Bruce J. [Center for Microfibrous Materials Manufacturing, Department of Chemical Engineering, 230 Ross Hall, Auburn University, Auburn, AL 36849 (United States)

2006-10-27

The Hg/HgO electrode is usually utilized as a reference electrode in alkaline solution such as for development of an alkaline hydrogen electrode. The reference electrode provides a suitable reference point but is available from few commercial vendors and suffers from inadequate documentation on potential in varying electrolytes. A new numerical method uses activity, activity coefficients, and a few correlated empirical equations to determine the potential values in both dilute and concentrated sodium hydroxide solutions at temperatures of 0-90{sup o}C and at concentrations of 0.100-12.8mol kg{sub H{sub 2}O}{sup -1}. The computed potentials of the Hg/HgO electrodes versus a normal hydrogen electrode (NHE) at 25{sup o}C and 1atm are 0.1634V for 0.100m, 0.1077V for 1.00m, and 0.0976V for 1.45m NaOH solutions. The Hg/HgO reduction potential further changes to -0.0751V versus NHE and hydrogen evolution potential changes to -0.9916V versus NHE in a solution of 30.0wt.% NaOH at 80{sup o}C. The calculated values are compared with the measured data at 25 and 75{sup o}C. The experimental data agree well with the numerical values computed from the theoretical and empirical equations. (author)

Rubber-based carbon electrode materials derived from dumped tires for efficient sodium-ion storage.

Science.gov (United States)

Wu, Zhen-Yue; Ma, Chao; Bai, Yu-Lin; Liu, Yu-Si; Wang, Shi-Feng; Wei, Xiao; Wang, Kai-Xue; Chen, Jie-Sheng

2018-04-03

The development of sustainable and low cost electrode materials for sodium-ion batteries has attracted considerable attention. In this work, a carbon composite material decorated with in situ generated ZnS nanoparticles has been prepared via a simple pyrolysis of the rubber powder from dumped tires. Upon being used as an anode material for sodium-ion batteries, the carbon composite shows a high reversible capacity and rate capability. A capacity as high as 267 mA h g-1 is still retained after 100 cycles at a current density of 50 mA g-1. The well dispersed ZnS nanoparticles in carbon significantly enhance the electrochemical performance. The carbon composites derived from the rubber powder are proposed as promising electrode materials for low-cost, large-scale energy storage devices. This work provides a new and effective method for the reuse of dumped tires, contributing to the recycling of valuable waste resources.

Quantitative determination of polysulfide in albumins, plasma proteins and biological fluid samples using a novel combined assays approach.

Science.gov (United States)

Ikeda, Mayumi; Ishima, Yu; Shibata, Akitomo; Chuang, Victor T G; Sawa, Tomohiro; Ihara, Hideshi; Watanabe, Hiroshi; Xian, Ming; Ouchi, Yuya; Shimizu, Taro; Ando, Hidenori; Ukawa, Masami; Ishida, Tatsuhiro; Akaike, Takaaki; Otagiri, Masaki; Maruyama, Toru

2017-05-29

Hydrogen sulfide (H 2 S) signaling involves polysulfide (RSS n SR') formation on various proteins. However, the current lack of sensitive polysulfide detection assays poses methodological challenges for understanding sulfane sulfur homeostasis and signaling. We developed a novel combined assay by modifying Sulfide Antioxidant Buffer (SAOB) to produce an "Elimination Method of Sulfide from Polysulfide" (EMSP) treatment solution that liberates sulfide, followed with methylene blue (MB) sulfide detection assay. The combined EMSP-MB sulfide detection assay performed on low molecular weight sulfur species showed that sulfide was produced from trisulfide compounds such as glutathione trisulfide and diallyl trisulfide, but not from the thiol compounds such as cysteine, cystine and glutathione. In the case of plasma proteins, this novel combined detection assay revealed that approximately 14.7, 1.7, 3.9, 3.7 sulfide mol/mol released from human serum albumin, α 1 -anti-trypsin, α 1 -acid glycoprotein and ovalbumin, respectively, suggesting that serum albumin is a major pool of polysulfide in human blood circulation. Taken together with the results of albumins of different species, the liberated sulfide has a good correlation with cysteine instead of methionine, indicating the site of incorporation of polysulfide is cysteine. With this novel sulfide detention assay, approximately 8,000, 120 and 1100 μM of polysulfide concentrations was quantitated in human healthy plasma, saliva and tear, respectively. Our promising polysulfide specific detection assay can be a very important tool because quantitative determination of polysulfide sheds light on the functional consequence of protein-bound cysteine polysulfide and expands the research area of reactive oxygen to reactive polysulfide species. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermophysical properties of inorganic polysulfides. Technical progress report. [Na/sub 2/S/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Janz, G J

1979-12-01

The present project was initiated May 15, 1979, and was undertaken to meet the data needs for thermophysical properties of selected polysulfides, as required directly or indirectly in the advanced battery development programs, and to advance the theoretical studies on the mechanisms of melting of ionic compounds. The research approach is briefly summarized and the accomplishments and status of the three principal tasks that have been undertaken in this initial period are reported: preparative chemistry; the MSDC-RPI DSC facility; and thermophysical properties measurements. First results for sodium trisulfide for the melting point, the enthalpy of fusion, and entrophy of fusion are 238.7/sup 0/C, 5538 cal/mol, and 10.83 cal/deg mol. 1 figure, 6 tables.

Kinetics and mechanism of the deep electrochemical oxidation of sodium diclofenac on a boron-doped diamond electrode

Science.gov (United States)

Vedenyapina, M. D.; Borisova, D. A.; Rosenwinkel, K.-H.; Weichgrebe, D.; Stopp, P.; Vedenyapin, A. A.

2013-08-01

The kinetics and mechanism of the deep oxidation of sodium diclofenac on a boron-doped diamond electrode are studied to develop a technique for purifying wastewater from pharmaceutical products. The products of sodium diclofenac electrolysis are analyzed using cyclic voltammetry and nuclear magnetic resonance techniques. It is shown that the toxicity of the drug and products of its electrolysis decreases upon its deep oxidation.

Correlating microstructure and activity for polysulfide reduction and oxidation at WS₂ electrocatalysts

DEFF Research Database (Denmark)

Stephens, Ifan E.L.; Ducati, Caterina; Fray, Derek J.

2013-01-01

The polysulfide reduction and oxidation activity of WS2 electrocatalysts was studied. This was undertaken with a specific view to improve the efficiency of the polysulfide-bromine redox flow battery, for large scale energy storage. Using data from the literature, it is estimated that the catalysts.......47 and 1 M NaOH, simulating the operating conditions of a half-charged polysulfide-bromine redox flow battery. The catalyst activity increased in the following order: IF-WS2

Method of making a sodium sulfur battery

Science.gov (United States)

Elkins, Perry E.

1981-01-01

A method of making a portion of a sodium sulfur battery is disclosed. The battery portion made is a portion of the container which defines the volume for the cathodic reactant materials which are sulfur and sodium polysulfide materials. The container portion is defined by an outer metal casing with a graphite liner contained therein, the graphite liner having a coating on its internal diameter for sealing off the porosity thereof. The steel outer container and graphite pipe are united by a method which insures that at the operating temperature of the battery, relatively low electrical resistance exists between the two materials because they are in intimate contact with one another.

Cubic KTi2(PO4)3 as electrode materials for sodium-ion batteries.

Science.gov (United States)

Han, Jin; Xu, Maowen; Niu, Yubin; Jia, Min; Liu, Ting; Li, Chang Ming

2016-12-01

A novel cubic KTi2(PO4)3 is successfully synthesized via a facile hydrothermal method combined with a subsequent annealing treatment and further used as electrode material for sodium-ion batteries for the first time. For comparison, carbon-coated KTi2(PO4)3 obtained by a normal cane sugar-assisted method reveals superior electrochemical performances in sodium-ion battery. Besides of the high coulombic efficiency of nearly 100% after 100 cycles, a stable capacity of 112mAhg(-1) can be achieved at 0.5C after 100 cycles, and still maintains to 105mAhg(-1) after 500 cycles with capacity retention of approximately 90%. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of Nickel Particle Size and Graphene Support on the Electrochemical Performance of Lithium/Dissolved Polysulfide Batteries

International Nuclear Information System (INIS)

Mosavati, Negar; Chitturi, Venkateswara Rao; Arava, Leela Mohana Reddy; Salley, Steven O.; Ng, K.Y. Simon

2015-01-01

Highlights: • Electrodes with different nano size Ni particles are prepared. • The electrocatalytic effect of Ni nanoparticle sizes is investigated. • The graphene supported Ni nanoparticle is synthesized. • The effect of the graphene support to the anchor Ni nanoparticle is investigated. • Ni/graphene electrode exhibits remarkably enhanced discharge capacity. - Abstract: The electrocatalytic effect of nickel (Ni) nanoparticle sizes on the lithium polysulfide conversion reactions in dissolved lithium sulfur battery configuration is investigated. The Ni particles of 20 nm with the higher cathode surface area show a superior capacity of 1066 mAh g −1 sulfur compared to Ni particles of 40 and 100 nm for the first cycle. In addition, to further improve the capacity retention and discharge capacity of the cell, the effect of the graphene support on Ni nanoparticle dispersion and cycling performance is investigated. The results show a significant improvement in the discharge capacity compared to the other electrodes. This could be explained by the homogeneous distribution of Ni nanoparticle within the carbon matrix, which suppress the agglomeration and surface area loss of the Ni nanoparticle after cycling; as well as a synergetic effect of graphene structure and Ni nanoparticle.

Biologically produced sulfur particles and polysulfide ions

NARCIS (Netherlands)

Kleinjan, W.E.

2005-01-01

This thesis deals with the effects of particles of biologically produced sulfur (or 'biosulfur') on a biotechnological process for the removal of hydrogen sulfide from gas streams. Particular emphasis is given to the role of polysulfide ions in such a process. These

Molecularly Imprinted Polymer Enables High-Efficiency Recognition and Trapping Lithium Polysulfides for Stable Lithium Sulfur Battery.

Science.gov (United States)

Liu, Jie; Qian, Tao; Wang, Mengfan; Liu, Xuejun; Xu, Na; You, Yizhou; Yan, Chenglin

2017-08-09

Using molecularly imprinted polymer to recognize various target molecules emerges as a fascinating research field. Herein, we applied this strategy for the first time to efficiently recognize and trap long-chain polysulfides (Li 2 S x , x = 6-8) in lithium sulfur battery to minimize the polysulfide shuttling between anode and cathode, which enables us to achieve remarkable electrochemical performance including a high specific capacity of 1262 mAh g -1 at 0.2 C and superior capacity retention of over 82.5% after 400 cycles at 1 C. The outstanding performance is attributed to the significantly reduced concentration of long-chain polysulfides in electrolyte as evidenced by in situ UV/vis spectroscopy and Li 2 S nucleation tests, which were further confirmed by density functional theory calculations. The molecular imprinting is demonstrated as a promising approach to effectively prevent the free diffusion of long-chain polysulfides, providing a new avenue to efficiently recognize and trap lithium polysulfides for high-performance lithium sulfur battery with greatly suppressed shuttle effect.

A three-dimensional cathode matrix with bi-confinement effect of polysulfide for lithium-sulfur battery

Science.gov (United States)

Song, Ren-Sheng; Wang, Bo; Ruan, Ting-Ting; Wang, Lei; Luo, Hao; Wang, Fei; Gao, Tian-Tian; Wang, Dian-Long

2018-01-01

Soluble polysulfide shuttling is still the main cause of restricting the development of lithium-sulfur (Li-S) battery. Here, we propose a novel three-dimensional reduced graphene oxide@sulfur/nitrogen-doped porous carbon polyhedron/carbon nanotubes (rGO@S/NCP/CNTs) composite with bi-confinement effect of polysulfide as an effective cathode material. In rGO@S/NCP/CNTs, NCP provides physical confinement for sulfur and soluble polysulfide by its abundant micropores and mesopores, while oxygen functional groups of rGO provide strong chemical confinement to soluble polysulfide. Additionally, CNTs with one-dimensional conductivity enable facile transport of electrons. Therefore, the resulting rGO@S/NCP/CNTs composite shows an obvious enhancement in cycling performance for Li-S battery, and reversible capacities up to 738 mAh g-1 and 660 mAh g-1 over 100 and 200 cycles are remained at 0.2 C rate.

High Reversibility of Soft Electrode Materials in All-solid-state Batteries

Directory of Open Access Journals (Sweden)

Atsushi eSakuda

2016-05-01

Full Text Available All-solid-state batteries using inorganic solid electrolytes (SEs are considered to be ideal batteries for electric vehicles (EVs and plug-in hybrid electric vehicles (PHEVs because they are potentially safer than conventional lithium-ion batteries (LIBs. In addition, all-solid-state batteries are expected to have long battery lives owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy (more than 300 Wh kg-1 secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li3NbS4, have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric energy density of conventional LIBs.Favorable solid-solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to be given rise to cracks during fabrication and/or charge-discharge processes. Here we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid-solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approx. 400 mAh g-1, suggesting that the lithium niobium sulfide electrode charged and discharged without experiencing

Bifunctional separator as a polysulfide mediator for highly stable Li-S batteries

KAUST Repository

Abbas, Syed Ali

2016-05-24

The shuttling process involving lithium polysulfides is one of the major factors responsible for the degradation in capacity of lithium–sulfur batteries (LSBs). Herein, we demonstrate a novel and simple strategy—using a bifunctional separator, prepared by spraying poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on pristine separator—to obtain long-cycle LSBs. The negatively charged SO3– groups present in PSS act as an electrostatic shield for soluble lithium polysulfides through mutual coulombic repulsion, whereas PEDOT provides chemical interactions with insoluble polysulfides (Li2S, Li2S2). The dual shielding effect can provide an efficient protection from the shuttling phenomenon by confining lithium polysulfides to the cathode side of the battery. Moreover, coating with PEDOT:PSS transforms the surface of the separator from hydrophobic to hydrophilic, thereby improving the electrochemical performance. We observed an ultralow decay of 0.0364% per cycle when we ran the battery for 1000 cycles at 0.25 C—far superior to that of the pristine separator and one of the lowest recorded values reported at a low current density. We examined the versatility of our separator by preparing a flexible battery that functioned well under various stress conditions; it displayed flawless performance. Accordingly, this economical and simple strategy appears to be an ideal platform for commercialization of LSBs.

Bifunctional separator as a polysulfide mediator for highly stable Li-S batteries

KAUST Repository

Abbas, Syed Ali; Ibrahem, Mohammed Aziz; Hu, Lung-hao; Lin, Chia-Nan; Fang, Jason; Boopathi, Karunakara Moorthy; Wang, Pen-Cheng; Li, Lain-Jong; Chu, Chih Wei

2016-01-01

The shuttling process involving lithium polysulfides is one of the major factors responsible for the degradation in capacity of lithium–sulfur batteries (LSBs). Herein, we demonstrate a novel and simple strategy—using a bifunctional separator, prepared by spraying poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on pristine separator—to obtain long-cycle LSBs. The negatively charged SO3– groups present in PSS act as an electrostatic shield for soluble lithium polysulfides through mutual coulombic repulsion, whereas PEDOT provides chemical interactions with insoluble polysulfides (Li2S, Li2S2). The dual shielding effect can provide an efficient protection from the shuttling phenomenon by confining lithium polysulfides to the cathode side of the battery. Moreover, coating with PEDOT:PSS transforms the surface of the separator from hydrophobic to hydrophilic, thereby improving the electrochemical performance. We observed an ultralow decay of 0.0364% per cycle when we ran the battery for 1000 cycles at 0.25 C—far superior to that of the pristine separator and one of the lowest recorded values reported at a low current density. We examined the versatility of our separator by preparing a flexible battery that functioned well under various stress conditions; it displayed flawless performance. Accordingly, this economical and simple strategy appears to be an ideal platform for commercialization of LSBs.

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

Science.gov (United States)

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.

High Reversibility of “Soft” Electrode Materials in All-Solid-State Batteries

Energy Technology Data Exchange (ETDEWEB)

Sakuda, Atsushi, E-mail: a.sakuda@aist.go.jp; Takeuchi, Tomonari, E-mail: a.sakuda@aist.go.jp; Shikano, Masahiro; Sakaebe, Hikari; Kobayashi, Hironori [Department of Energy and Environment, Research Institute for Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda (Japan)

2016-05-10

All-solid-state batteries using inorganic solid electrolytes (SEs) are considered to be ideal batteries for electric vehicles and plug-in hybrid electric vehicles because they are potentially safer than conventional lithium-ion batteries (LIBs). In addition, all-solid-state batteries are expected to have long battery life owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy density (more than 300 Wh kg{sup −1}) secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li{sub 3}NbS{sub 4}, have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric-energy density of conventional LIBs. Favorable solid–solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to give rise to cracks during fabrication and/or charge–discharge processes. Here, we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid–solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approximately 400 mAh g{sup −1} suggesting that the lithium niobium sulfide electrode charged and discharged without

High Reversibility of “Soft” Electrode Materials in All-Solid-State Batteries

International Nuclear Information System (INIS)

Sakuda, Atsushi; Takeuchi, Tomonari; Shikano, Masahiro; Sakaebe, Hikari; Kobayashi, Hironori

2016-01-01

All-solid-state batteries using inorganic solid electrolytes (SEs) are considered to be ideal batteries for electric vehicles and plug-in hybrid electric vehicles because they are potentially safer than conventional lithium-ion batteries (LIBs). In addition, all-solid-state batteries are expected to have long battery life owing to the inhibition of chemical side reactions because only lithium ions move through the typically used inorganic SEs. The development of high-energy density (more than 300 Wh kg −1 ) secondary batteries has been eagerly anticipated for years. The application of high-capacity electrode active materials is essential for fabricating such batteries. Recently, we proposed metal polysulfides as new electrode materials. These materials show higher conductivity and density than sulfur, which is advantageous for fabricating batteries with relatively higher energy density. Lithium niobium sulfides, such as Li 3 NbS 4 , have relatively high density, conductivity, and rate capability among metal polysulfide materials, and batteries with these materials have capacities high enough to potentially exceed the gravimetric-energy density of conventional LIBs. Favorable solid–solid contact between the electrode and electrolyte particles is a key factor for fabricating high performance all-solid-state batteries. Conventional oxide-based positive electrode materials tend to give rise to cracks during fabrication and/or charge–discharge processes. Here, we report all-solid-state cells using lithium niobium sulfide as a positive electrode material, where favorable solid–solid contact was established by using lithium sulfide electrode materials because of their high processability. Cracks were barely observed in the electrode particles in the all-solid-state cells before or after charging and discharging with a high capacity of approximately 400 mAh g −1 suggesting that the lithium niobium sulfide electrode charged and discharged without experiencing

Investigation on the electrode process of the Mn(II)/Mn(III) couple in redox flow battery

International Nuclear Information System (INIS)

Xue Fangqin; Wang Yongliang; Wang Wenhong; Wang Xindong

2008-01-01

The Mn(II)/Mn(III) couple has been recognized as a potential anode for redox flow batteries to take the place of the V(IV)/V(V) in all-vanadium redox battery (VRB) and the Br 2 /Br - in sodium polysulfide/bromine (PSB) because it has higher standard electrode potential. In this study, the electrochemical behavior of the Mn(II)/Mn(III) couple on carbon felt and spectral pure graphite were investigated by cyclic voltammetry, steady polarization curve, electrochemical impedance spectroscopy, transient potential-step experiment, X-ray diffraction and charge-discharge experiments. Results show that the Mn(III) disproportionation reaction phenomena is obvious on the carbon felt electrode while it is weak on the graphite electrode owing to its fewer active sites. The reaction mechanism on carbon felt was discussed in detail. The reversibility of Mn(II)/Mn(III) is best when the sulfuric acid concentration is 5 M on the graphite electrode. Performance of a RFB employing Mn(II)/Mn(III) couple as anolyte active species and V(III)/V(II) as catholyte ones was evaluated with constant-current charge-discharge tests. The average columbic efficiency is 69.4% and the voltage efficiency is 90.4% at a current density of 20 mA cm -2 . The whole energy efficiency is 62.7% close to that of the all-vanadium battery and the average discharge voltage is about 14% higher than that of an all-vanadium battery. The preliminary exploration shows that the Mn(II)/Mn(III) couple is electrochemically promising for redox flow battery

A Lithium/Polysulfide Battery with Dual-Working Mode Enabled by Liquid Fuel and Acrylate-Based Gel Polymer Electrolyte.

Science.gov (United States)

Liu, Ming; Ren, Yuxun; Zhou, Dong; Jiang, Haoran; Kang, Feiyu; Zhao, Tianshou

2017-01-25

The low density associated with low sulfur areal loading in the solid-state sulfur cathode of current Li-S batteries is an issue hindering the development of this type of battery. Polysulfide catholyte as a recyclable liquid fuel was proven to enhance both the energy density and power density of the battery. However, a critical barrier with this lithium (Li)/polysulfide battery is that the shuttle effect, which is the crossover of polysulfides and side deposition on the Li anode, becomes much more severe than that in conventional Li-S batteries with a solid-state sulfur cathode. In this work, we successfully applied an acrylate-based gel polymer electrolyte (GPE) to the Li/polysulfide system. The GPE layer can effectively block the detrimental diffusion of polysulfides and protect the Li metal from the side passivation reaction. Cathode-static batteries utilizing 2 M catholyte (areal sulfur loading of 6.4 mg cm -2 ) present superior cycling stability (727.4 mAh g -1 after 500 cycles at 0.2 C) and high rate capability (814 mAh g -1 at 2 C) and power density (∼10 mW cm -2 ), which also possess replaceable and encapsulated merits for mobile devices. In the cathode-flow mode, the Li/polysulfide system with catholyte supplied from an external tank demonstrates further improved power density (∼69 mW cm -2 ) and stable cycling performance. This novel and simple Li/polysulfide system represents a significant advancement of high energy density sulfur-based batteries for future power sources.

A natural carbonized leaf as polysulfide diffusion inhibitor for high-performance lithium-sulfur battery cells.

Science.gov (United States)

Chung, Sheng-Heng; Manthiram, Arumugam

2014-06-01

Attracted by the unique tissue and functions of leaves, a natural carbonized leaf (CL) is presented as a polysulfide diffusion inhibitor in lithium-sulfur (Li-S) batteries. The CL that is covered on the pure sulfur cathode effectively suppresses the polysulfide shuttling mechanism and enables the use of pure sulfur as the cathode. A low charge resistance and a high discharge capacity of 1320 mA h g(-1) arise from the improved cell conductivity due to the innately integral conductive carbon network of the CL. The unique microstructure of CL leads to a high discharge/charge efficiency of >98 %, low capacity fade of 0.18 % per cycle, and good long-term cyclability over 150 cycles. The structural gradient and the micro/mesoporous adsorption sites of CL effectively intercept/trap the migrating polysulfides and facilitate their reutilization. The green CL polysulfide diffusion inhibitor thus offers a viable approach for developing high-performance lithium-sulfur batteries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separator Decoration with Cobalt/Nitrogen Codoped Carbon for Highly Efficient Polysulfide Confinement in Lithium-Sulfur Batteries.

Science.gov (United States)

Hu, Wen; Hirota, Yuichiro; Zhu, Yexin; Yoshida, Nao; Miyamoto, Manabu; Zheng, Tao; Nishiyama, Norikazu

2017-09-22

A macro-/mesoporous Co-N-C-decorated separator is proposed to confine and reutilize migrating polysulfides. Endowed with a desirable structure and synchronous lithio- and sulfiphilic chemistry, the macro-/mesoporous Co-N-C interface manipulates large polysulfide adsorption uptake, enabling good polysulfide adsorption kinetics, reversible electrocatalysis toward redox of anchored polysulfides, and facile charge transport. It significantly boosts the performance of a simple 70 wt % S/MWCNTs (MWCNTs=multi-walled carbon nanotubes) cathode, achieving high initial capacities (e.g., 1406 mAh g -1 at 0.2C, 1203 mAh g -1 at 1C), nearly 100 % Coulombic efficiencies, and high reversible capacities after cycle tests (e.g., 828.4 mAh g -1 at 1C after 100 cycles) at both low and high current rates. These results demonstrate that decorating separator with macro-/mesoporous Co-N-C paves a feasible way for developing advanced Li-S batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

VS4 Nanoparticles Anchored on Graphene Sheets as a High-Rate and Stable Electrode Material for Sodium Ion Batteries.

Science.gov (United States)

Pang, Qiang; Zhao, Yingying; Yu, Yanhao; Bian, Xiaofei; Wang, Xudong; Wei, Yingjin; Gao, Yu; Chen, Gang

2018-02-22

The size and conductivity of the electrode materials play a significant role in the kinetics of sodium-ion batteries. Various characterizations reveal that size-controllable VS 4 nanoparticles can be successfully anchored on the surface of graphene sheets (GSs) by a simple cationic-surfactant-assisted hydrothermal method. When used as an electrode material for sodium-ion batteries, these VS 4 @GS nanocomposites show large specific capacity (349.1 mAh g -1 after 100 cycles), excellent long-term stability (84 % capacity retention after 1200 cycles), and high rate capability (188.1 mAh g -1 at 4000 mA g -1 ). A large proportion of the capacity was contributed by capacitive processes. This remarkable electrochemical performance was attributed to synergistic interactions between nanosized VS 4 particles and a highly conductive graphene network, which provided short diffusion pathways for Na + ions and large contact areas between the electrolyte and electrode, resulting in considerably improved electrochemical kinetic properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A sulfur–microporous carbon composite positive electrode for lithium/sulfur and silicon/sulfur rechargeble batteries

Directory of Open Access Journals (Sweden)

Takuya Takahashi

2015-12-01

Full Text Available Sulfur is an advantageous material as a promising next-generation positive electrode material for high-energy lithium batteries due to a high theoretical capacity of 1672 mA h g−1 although its discharge potential is somewhat modest: ca. 2 V vs Li/Li+. However, a sulfur positive electrode has some crucial problems for practical use, which are mainly attributed to the dissolution of its intermediate products in charge–discharge processes. In order to resolve the dissolution problem of lithium polysulfide, we attempted to synthesize a sulfur–microporous activated carbon (AC composite positive electrode. Moreover, we have systematically researched the battery performance of sulfur–microporous AC positive electrode with variations of electrolytes as well as negative electrodes, and found its promising positive electrode performance for a next-generation rechargeable battery.

Sulfur based electrode materials for secondary batteries

Science.gov (United States)

Hao, Yong

Developing next generation secondary batteries has attracted much attention in recent years due to the increasing demand of high energy and high power density energy storage for portable electronics, electric vehicles and renewable sources of energy. This dissertation investigates sulfur based advanced electrode materials in Lithium/Sodium batteries. The electrochemical performances of the electrode materials have been enhanced due to their unique nano structures as well as the formation of novel composites. First, a nitrogen-doped graphene nanosheets/sulfur (NGNSs/S) composite was synthesized via a facile chemical reaction deposition. In this composite, NGNSs were employed as a conductive host to entrap S/polysulfides in the cathode part. The NGNSs/S composite delivered an initial discharge capacity of 856.7 mAh g-1 and a reversible capacity of 319.3 mAh g-1 at 0.1C with good recoverable rate capability. Second, NGNS/S nanocomposites, synthesized using chemical reaction-deposition method and low temperature heat treatment, were further studied as active cathode materials for room temperature Na-S batteries. Both high loading composite with 86% gamma-S8 and low loading composite with 25% gamma-S8 have been electrochemically evaluated and compared with both NGNS and S control electrodes. It was found that low loading NGNS/S composite exhibited better electrochemical performance with specific capacity of 110 and 48 mAh g-1 at 0.1C at the 1st and 300th cycle, respectively. The Coulombic efficiency of 100% was obtained at the 300th cycle. Third, high purity rock-salt (RS), zinc-blende (ZB) and wurtzite (WZ) MnS nanocrystals with different morphologies were successfully synthesized via a facile solvothermal method. RS-, ZB- and WZ-MnS electrodes showed the capacities of 232.5 mAh g-1, 287.9 mAh g-1 and 79.8 mAh g-1 at the 600th cycle, respectively. ZB-MnS displayed the best performance in terms of specific capacity and cyclability. Interestingly, MnS electrodes

Garlic-Derived Organic Polysulfides and Myocardial Protection123

Science.gov (United States)

Bradley, Jessica M; Organ, Chelsea L; Lefer, David J

2016-01-01

For centuries, garlic has been shown to exert substantial medicinal effects and is considered to be one of the best disease-preventative foods. Diet is important in the maintenance of health and prevention of many diseases including cardiovascular disease (CVD). Preclinical and clinical evidence has shown that garlic reduces risks associated with CVD by lowering cholesterol, inhibiting platelet aggregation, and lowering blood pressure. In recent years, emerging evidence has shown that hydrogen sulfide (H2S) has cardioprotective and cytoprotective properties. The active metabolite in garlic, allicin, is readily degraded into organic diallyl polysulfides that are potent H2S donors in the presence of thiols. Preclinical studies have shown that enhancement of endogenous H2S has an impact on vascular reactivity. In CVD models, the administration of H2S prevents myocardial injury and dysfunction. It is hypothesized that these beneficial effects of garlic may be mediated by H2S-dependent mechanisms. This review evaluates the current knowledge concerning the cardioprotective effects of garlic-derived diallyl polysulfides. PMID:26764335

Stabilized Lithium-Metal Surface in a Polysulfide-Rich Environment of Lithium-Sulfur Batteries.

Science.gov (United States)

Zu, Chenxi; Manthiram, Arumugam

2014-08-07

Lithium-metal anode degradation is one of the major challenges of lithium-sulfur (Li-S) batteries, hindering their practical utility as next-generation rechargeable battery chemistry. The polysulfide migration and shuttling associated with Li-S batteries can induce heterogeneities of the lithium-metal surface because it causes passivation by bulk insulating Li2S particles/electrolyte decomposition products on a lithium-metal surface. This promotes lithium dendrite formation and leads to poor lithium cycling efficiency with complicated lithium surface chemistry. Here, we show copper acetate as a surface stabilizer for lithium metal in a polysulfide-rich environment of Li-S batteries. The lithium surface is protected from parasitic reactions with the organic electrolyte and the migrating polysulfides by an in situ chemical formation of a passivation film consisting of mainly Li2S/Li2S2/CuS/Cu2S and electrolyte decomposition products. This passivation film also suppresses lithium dendrite formation by controlling the lithium deposition sites, leading to a stabilized lithium surface characterized by a dendrite-free morphology and improved surface chemistry.

Harmony of computational quantum chemistry and experimental chemistry: Comprehensive DFT studies, microsynthesis, and characterization of mustard gas polysulfide analogues

Science.gov (United States)

Saeidian, Hamid; Faraz, Sajjad Mousavi; Mirjafary, Zohreh; Babri, Mehran

2018-05-01

After microsynthesis, structures of mustard gas polysulfide analogues were characterized using electron impact (EI) mass spectrometry. General EI fragmentation pathways for such compounds are proposed. The structure of sulfur mustard (HD) and its two other polysulfide analogues have been examined through B3LYP/6-311++G(2d, 2p) calculations. Geometrical analysis of HD shows that the calculated bond distances are satisfactorily comparable with experimental results. Calculated NMR chemical shifts for HD also were compared with experimental data, indicating good agreement both for 1H and 13C atoms. The vibrational frequencies of HD and polysulfide analogues have been precisely assigned. At the end, based on visual inspection of lowest unoccupied molecular orbitals and the relative difference in the total energies of their episulfonium ions, relative reactivity of HD and its polysulfide analogues were investigated.

Flexible three-dimensional electrodes of hollow carbon bead strings as graded sulfur reservoirs and the synergistic mechanism for lithium–sulfur batteries

Energy Technology Data Exchange (ETDEWEB)

Yang, Dan [College of Materials Science and Engineering, Sichuan University, Chengdu, 610064 (China); Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Ni, Wei, E-mail: niwei@iccas.ac.cn [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Cheng, Jianli; Wang, Zhuanpei; Wang, Ting; Guan, Qun [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Zhang, Yun, E-mail: y_zhang@scu.edu.cn [College of Materials Science and Engineering, Sichuan University, Chengdu, 610064 (China); Wu, Hao [College of Materials Science and Engineering, Sichuan University, Chengdu, 610064 (China); Li, Xiaodong [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Wang, Bin, E-mail: edward.bwang@gmail.com [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China)

2017-08-15

Graphical abstract: Flexible three-dimensional electrode comprised of stringed N-doped hollow carbon spheres shows a synergistic sulfur confinement mechanism and a higher energy/power density for the promising lithium-sulfur batteries compared with traditional electrodes. - Highlights: • Hollow carbon beads on string structure was first prepared. • Flexible 3D electrodes as graded reservoirs for polysulfides were conducted. • Synergistic effect for enhanced polysulfides storage was claimed. - Abstract: Three-dimensional (3D) flexible electrodes of stringed hollow nitrogen-doped (N-doped) carbon nanospheres as graded sulfur reservoirs and conductive frameworks were elaborately designed via a combination of the advantages of hollow structures, 3D electrodes and flexible devices. The as-prepared electrodes by a synergistic method of electrospinning, template sacrificing and activation for Li–S batteries without any binder or conductive additives but a 3D interconnected conductive network offered multiple transport paths for electrons and improved sulfur utilization and facilitated an easy access to Li{sup +} ingress/egress. With the increase of density of hollow carbon spheres in the strings, the self-supporting composite electrode reveals an enhanced synergistic mechanism for sulfur confinement and displays a better cycling stability and rate performance. It delivers a high initial specific capacity of 1422.6 mAh g{sup −1} at the current rate of 0.2C with the high sulfur content of 76 wt.%, and a much higher energy density of 754 Wh kg{sup −1} and power density of 1901 Wh kg{sup −1}, which greatly improve the energy/power density of traditional lithium–sulfur batteries and will be promising for further commercial applications.

Improvement of operational properties of shell limestone building materials by polysulfide solution impregnation

Directory of Open Access Journals (Sweden)

MASSALIMOV Ismail Alexandrovich

2017-06-01

Full Text Available The data of studies on the effectiveness of impregnation with polysulfide solutions of shell limestone used as facing and wall material, as well as for the manufacture of road products are presented. Modification of the limestone with the impregnating composition «Akvastat» created by the authors which is sulfur-containing water-based solution of calcium polysulfide containing alcohols and surfactants, can significantly reduce water absorption and increase durability of limestone. Impregnating composition on the basis of calcium polysulfide possesses density of 1.22–1.24 g/cm3, the infiltrant penetrates into the pore structure of limestone to a depth of 4 cm or more, depending on the density and structure of the sample. While the material is drying, sulfur nanoparticles are crystallized from the polysulfide solution in its pores. They partially fill pore space and form protective durable insoluble hydrophobic coating that impedes the penetration of water into the pores of the limestone, but preserves its vapor permeability, which is important for wall and decoration materials. The evaluation of protective coatings was performed with laser particle size analyzer, scanning probe microscope and a diffractometer. It showed that the average size of the particles forming the protective coating is in the range of 20–25 nm, the particles shape is spherical, the particles are elemental sulfur with orthorhombic structure of the crystal lattice. The processing of shell limestone with calcium polysulphide solution provides formation of coating based on nanosized sulfur on the surface of stone pores. The coating partially fills the pore space and, as it is hydrophobic, reduces the water absorption of the samples by a factor of 5–8, increases their average density by 22–27%, strength in 1,2–1,3 times, the softening factor by 6–19%, that makes possible to predict the increase of the durability of building materials based on shell limestone to 1

TiN nanoparticles on CNT-graphene hybrid support as noble-metal-free counter electrode for quantum-dot-sensitized solar cells.

Science.gov (United States)

Youn, Duck Hyun; Seol, Minsu; Kim, Jae Young; Jang, Ji-Wook; Choi, Youngwoo; Yong, Kijung; Lee, Jae Sung

2013-02-01

The development of an efficient noble-metal-free counter electrode is crucial for possible applications of quantum-dot-sensitized solar cells (QDSSCs). Herein, we present TiN nanoparticles on a carbon nanotube (CNT)-graphene hybrid support as a noble-metal-free counter electrode for QDSSCs employing a polysulfide electrolyte. The resulting TiN/CNT-graphene possesses an extremely high surface roughness, a good metal-support interaction, and less aggregation relative to unsupported TiN; it also has superior solar power conversion efficiency (4.13 %) when applying a metal mask, which is much higher than that of the state-of-the-art Au electrode (3.35 %). Based on electrochemical impedance spectroscopy measurements, the enhancement is ascribed to a synergistic effect between TiN nanoparticles and the CNT-graphene hybrid, the roles of which are to provide active sites for the reduction of polysulfide ions and electron pathways to TiN nanoparticles, respectively. The combination of graphene and CNTs leads to a favorable morphology that prevents stacking of graphene or bundling of CNTs, which maximizes the contact of the support with TiN nanoparticles and improves electron-transfer capability relative to either carbon material alone. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Negative electrodes for Na-ion batteries.

Science.gov (United States)

Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

2014-08-07

Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

Dual-Functional Graphene Carbon as Polysulfide Trapper for High-Performance Lithium Sulfur Batteries.

Science.gov (United States)

Zhang, Linlin; Wan, Fang; Wang, Xinyu; Cao, Hongmei; Dai, Xi; Niu, Zhiqiang; Wang, Yijing; Chen, Jun

2018-02-14

The lithium sulfur (Li-S) battery has attracted much attention due to its high theoretical capacity and energy density. However, its cycling stability and rate performance urgently need to improve because of its shuttle effect. Herein, oxygen-doped carbon on the surface of reduced graphene oxide (labeled as ODC/rGO) was fabricated to modify the separators of Li-S batteries to limit the dissolution of the lithium polysulfides. The mesoporous structure in ODC/rGO can not only serve as the physical trapper, but also provide abundant channels for fast ion transfer, which is beneficial for effective confinement of the dissoluble intermediates and superior rate performance. Moreover, the oxygen-containing groups in ODC/rGO are able to act as chemical adsorption sites to immobilize the lithium polysulfides, suppressing their dissolution in electrolyte to enhance the utilization of sulfur cathode in Li-S batteries. As a result, because of the synergetic effects of physical adsorption and chemical interaction to immobilize the soluble polysulfides, the Li-S batteries with the ODC/rGO-coated separator exhibit excellent rate performance and good long-term cycling stability with 0.057% capacity decay per cycle at 1.0 C after 600 cycles.

Structural and Mechanistic Insights into Hemoglobin-catalyzed Hydrogen Sulfide Oxidation and the Fate of Polysulfide Products

Energy Technology Data Exchange (ETDEWEB)

Vitvitsky, Victor; Yadav, Pramod K.; An, Sojin; Seravalli, Javier; Cho, Uhn-Soo; Banerjee, Ruma (Michigan-Med); (UNL)

2017-02-17

Hydrogen sulfide is a cardioprotective signaling molecule but is toxic at elevated concentrations. Red blood cells can synthesize H2S but, lacking organelles, cannot dispose of H2S via the mitochondrial sulfide oxidation pathway. We have recently shown that at high sulfide concentrations, ferric hemoglobin oxidizes H2S to a mixture of thiosulfate and iron-bound polysulfides in which the latter species predominates. Here, we report the crystal structure of human hemoglobin containing low spin ferric sulfide, the first intermediate in heme-catalyzed sulfide oxidation. The structure provides molecular insights into why sulfide is susceptible to oxidation in human hemoglobin but is stabilized against it in HbI, a specialized sulfide-carrying hemoglobin from a mollusk adapted to life in a sulfide-rich environment. We have also captured a second sulfide bound at a postulated ligand entry/exit site in the α-subunit of hemoglobin, which, to the best of our knowledge, represents the first direct evidence for this site being used to access the heme iron. Hydrodisulfide, a postulated intermediate at the junction between thiosulfate and polysulfide formation, coordinates ferric hemoglobin and, in the presence of air, generated thiosulfate. At low sulfide/heme iron ratios, the product distribution between thiosulfate and iron-bound polysulfides was approximately equal. The iron-bound polysulfides were unstable at physiological glutathione concentrations and were reduced with concomitant formation of glutathione persulfide, glutathione disulfide, and H2S. Hence, although polysulfides are unlikely to be stable in the reducing intracellular milieu, glutathione persulfide could serve as a persulfide donor for protein persulfidation, a posttranslational modification by which H2S is postulated to signal.

Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions

Energy Technology Data Exchange (ETDEWEB)

Rajput, Nav Nidhi; Murugesan, Vijayakumar; Shin, Yongwoo; Han, Kee Sung; Lau, Kah Chun; Chen, Junzheng; Liu, Jun; Curtiss, Larry A.; Mueller, Karl T.; Persson, Kristin A.

2017-04-10

Fundamental molecular level understanding of functional properties of liquid solutions provides an important basis for designing optimized electrolytes for numerous applica-tions. In particular, exhaustive knowledge of solvation structure, stability and transport properties is critical for developing stable electrolytes for fast charging and high energy density next-generation energy storage systems. Here we report the correlation between solubility, solvation structure and translational dynamics of a lithium salt (Li-TFSI) and polysulfides species using well-benchmarked classical molecular dynamics simulations combined with nuclear magnetic resonance (NMR). It is observed that the polysulfide chain length has a significant effect on the ion-ion and ion-solvent interaction as well as on the diffusion coefficient of the ionic species in solution. In particular, extensive cluster formation is observed in lower order poly-sulfides (Sx2-; x≤4), whereas the longer polysulfides (Sx2-; x>4) show high solubility and slow dynamics in the solu-tion. It is observed that optimal solvent/salt ratio is essen-tial to control the solubility and conductivity as the addi-tion of Li salt increases the solubility but decreases the mo-bility of the ionic species. This work provides a coupled theoretical and experimental study of bulk solvation struc-ture and transport properties of multi-component electro-lyte systems, yielding design metrics for developing optimal electrolytes with improved stability and solubility.

Garlic oil polysulfides: H2S- and O2-independent prooxidants in buffer and antioxidants in cells

Science.gov (United States)

DeLeon, Eric R.; Gao, Yan; Huang, Evelyn

2016-01-01

The health benefits of garlic and other organosulfur-containing foods are well recognized and have been attributed to both prooxidant and antioxidant activities. The effects of garlic are surprisingly similar to those of hydrogen sulfide (H2S), which is also known to be released from garlic under certain conditions. However, recent evidence suggests that polysulfides, not H2S, may be the actual mediator of physiological signaling. In this study, we monitored formation of H2S and polysulfides from garlic oil in buffer and in human embryonic kidney (HEK) 293 cells with fluorescent dyes, 7-azido-4-methylcoumarin and SSP4, respectively and redox activity with two redox indicators redox-sensitive green fluorescent protein (roGFP) and DCF. Our results show that H2S release from garlic oil in buffer requires other low-molecular-weight thiols, such as cysteine (Cys) or glutathione (GSH), whereas polysulfides are readily detected in garlic oil alone. Administration of garlic oil to cells rapidly increases intracellular polysulfide but has minimal effects on H2S unless Cys or GSH are also present in the extracellular medium. We also observed that garlic oil and diallyltrisulfide (DATS) potently oxidized roGFP in buffer but did not affect DCF. This appears to be a direct polysulfide-mediated oxidation that does not require a reactive oxygen species intermediate. Conversely, when applied to cells, garlic oil became a significant intracellular reductant independent of extracellular Cys or GSH. This suggests that intracellular metabolism and further processing of the sulfur moieties are necessary to confer antioxidant properties to garlic oil in vivo. PMID:27101293

A novel strategy for high-stability lithium sulfur batteries by in situ formation of polysulfide adsorptive-blocking layer

Science.gov (United States)

Jin, Liming; Li, Gaoran; Liu, Binhong; Li, Zhoupeng; Zheng, Junsheng; Zheng, Jim P.

2017-07-01

Lithium sulfur (Lisbnd S) batteries are one of the most promising energy storage devices owing to their high energy and power density. However, the shuttle effect as a key barrier hinders its practical application by resulting in low coulombic efficiency and poor cycling performance. Herein, a novel design of in situ formed polysulfide adsorptive-blocking layer (PAL) on the cathode surface was developed to tame the polysulfide shuttling and promote the cycling stability for Lisbnd S batteries. The PAL is consisted of La2S3, which is capable to chemically adsorb polysulfide via the strong interaction of Lasbnd S bond and Ssbnd S bond, and build an effective barrier against sulfur escaping. Moreover, the La2S3 is capable to suppress the crystallization of Li2S and promote the ion transfer, which contributes to the reduced internal resistance of batteries. Furthermore, the by-product LiNO3 simultaneously forms a stable anode solid and electrolyte interface to further inhibit the polysulfide shuttle. By this simple and convenient method, the resultant Lisbnd S batteries achieved exceptional cycling stability with an ultralow decay rate of 0.055% since the 10th cycle.

Stabilized sulfur as cathodes for room temperature sodium-ion batteries.

Energy Technology Data Exchange (ETDEWEB)

Xu, Yunhua [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Liu, Yang [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies; Zhu, Yujie [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Zheng, Shiyou [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Liu, Yihang [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Luo, Chao [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Gaskell, Karen [Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry; Eichhorn, Bryan [Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry; Wang, Chunsheng [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering

2013-05-01

Sodium-sulfur batteries, offering high capacity and low cost, are promising alternative to lithium-ion batteries for large-scale energy storage applications. The conventional sodium-sulfur batteries, operating at a high temperature of 300–350°C in a molten state, could lead to severe safety problems. However, the room temperature sodium-sulfur batteries using common organic liuid electrolytes still face a significant challenge due to the dissolution of intermediate sodium polysulfides. For this study, we developed room temperatue sodium-sulfur batteries using a unique porous carbon/sulfur (C/S) composite cathode, which was synthesized by infusing sulfur vapor into porous carbon sphere particles at a high temperatrure of 600°C. The porous C/S composites delivered a reversible capacity of ~860 mAh/g and retained 83% after 300 cycles. The Coulombic efficiency of as high as 97% was observed over 300 cycles. The superior electrochemical performance is attrbuted to the super sulfur stability as evidenced by its lower sensitivity to probe beam irradiation in TEM, XPS and Raman charaterization and high evaperation temperature in TGA. The results make it promising for large-scale grid energy storage and electric vehicles.

Improved efficiency of CdS quantum dot sensitized solar cell with an organic redox couple and a polymer counter electrode

International Nuclear Information System (INIS)

Shu, Ting; Li, Xiong; Ku, Zhi-Liang; Wang, Shi; Wu, Shi; Jin, Xiao-Hong; Hu, Chun-Di

2014-01-01

Highlights: • The organic AT - /BAT and T - /T 2 redox couples were used in CdS QDSSCs. • The AT - /BAT and PEDOT are better than polysulfide electrolyte and Pt and CoS CEs. • An improved η of 1.53% was obtained with the AT - /BAT electrolyte and the PEDOT CE. • PEDOT CE deposited at high deposition charge has better electrochemical activity. • The AT - /BAT outperformed T - /T 2 electrolyte due to suppressed charge recombination. - Abstract: Quantum dot sensitized solar cells (QDSSCs) based on an organic thiolate/disulfide redox couple (C 7 H 5 N 4 S - /C 14 H 10 N 8 S 2 or C 2 H 3 N 4 S - /C 4 H 6 N 8 S 2 ) and a polymer counter electrode [poly (3, 4-ethylenedioxythiophene), PEDOT] were fabricated and their photovoltaic performance were investigated. In CdS QDSSC, the organic C 7 H 5 N 4 S - /C 14 H 10 N 8 S 2 electrolyte shows better performance than the polysulfide electrolyte, and the PEDOT counter electrode exhibits higher efficiency than that of the Pt counter electrode and the CoS counter electrode. An efficiency of 1.53% was achieved in this QDSSC. The influences of the morphology and the deposition charge of the PEDOT counter electrodes on the cell performance were also studied. Furthermore, it was found that the C 7 H 5 N 4 S - /C 14 H 10 N 8 S 2 redox couple outperformed the C 2 H 3 N 4 S - /C 4 H 6 N 8 S 2 redox couple due to reduced electron recombination

Electrochemical oxidation and detection of sodium urate in alkaline ...

African Journals Online (AJOL)

Electrochemical behaviour of copper oxides electrode in the presence of sodium urate was investigated. The correlation between the anodic oxidation and the amperometric detection of sodium urate in the alkaline medium on copper oxides electrode was analysed by cyclic voltammetry (CV) and electrochemical ...

Ti Porous Film-Supported NiCo₂S₄ Nanotubes Counter Electrode for Quantum-Dot-Sensitized Solar Cells.

Science.gov (United States)

Deng, Jianping; Wang, Minqiang; Song, Xiaohui; Yang, Zhi; Yuan, Zhaolin

2018-04-17

In this paper, a novel Ti porous film-supported NiCo₂S₄ nanotube was fabricated by the acid etching and two-step hydrothermal method and then used as a counter electrode in a CdS/CdSe quantum-dot-sensitized solar cell. Measurements of the cyclic voltammetry, Tafel polarization curves, and electrochemical impedance spectroscopy of the symmetric cells revealed that compared with the conventional FTO (fluorine doped tin oxide)/Pt counter electrode, Ti porous film-supported NiCo₂S₄ nanotubes counter electrode exhibited greater electrocatalytic activity toward polysulfide electrolyte and lower charge-transfer resistance at the interface between electrolyte and counter electrode, which remarkably improved the fill factor, short-circuit current density, and power conversion efficiency of the quantum-dot-sensitized solar cell. Under illumination of one sun (100 mW/cm²), the quantum-dot-sensitized solar cell based on Ti porous film-supported NiCo₂S₄ nanotubes counter electrode achieved a power conversion efficiency of 3.14%, which is superior to the cell based on FTO/Pt counter electrode (1.3%).

Metal–Organic Framework-Based Separators for Enhancing Li–S Battery Stability: Mechanism of Mitigating Polysulfide Diffusion

KAUST Repository

Li, Mengliu

2017-09-13

The shuttling effect of polysulfides severely hinders the cycle performance and commercialization of Li–S batteries, and significant efforts have been devoted to searching for feasible solutions to mitigate the effect in the past two decades. Recently, metal–organic frameworks (MOFs) with rich porosity, nanometer cavity sizes, and high surface areas have been claimed to be effective in suppressing polysulfide migration. However, the formation of large-scale and grain boundary-free MOFs is still very challenging, where a large number of grain boundaries of MOF particles may also allow the diffusion of polysulfides. Hence, it is still controversial whether the pores in MOFs or the grain boundaries play the critical role. In this study, we perform a comparative study for several commonly used MOFs, and our experimental results and analysis prove that a layer of MOFs on a separator did enhance the capacity stability. Our results suggest that the chemical stability and the aggregation (packing) morphology of MOF particles play more important roles than the internal cavity size in MOFs.

Metal–Organic Framework-Based Separators for Enhancing Li–S Battery Stability: Mechanism of Mitigating Polysulfide Diffusion

KAUST Repository

Li, Mengliu; Wan, Yi; Huang, Jing-Kai; Assen, Ayalew Hussen Assen; Hsiung, Chia-En; Jiang, Hao; Han, Yu; Eddaoudi, Mohamed; Lai, Zhiping; Ming, Jun; Li, Lain-Jong

2017-01-01

The shuttling effect of polysulfides severely hinders the cycle performance and commercialization of Li–S batteries, and significant efforts have been devoted to searching for feasible solutions to mitigate the effect in the past two decades. Recently, metal–organic frameworks (MOFs) with rich porosity, nanometer cavity sizes, and high surface areas have been claimed to be effective in suppressing polysulfide migration. However, the formation of large-scale and grain boundary-free MOFs is still very challenging, where a large number of grain boundaries of MOF particles may also allow the diffusion of polysulfides. Hence, it is still controversial whether the pores in MOFs or the grain boundaries play the critical role. In this study, we perform a comparative study for several commonly used MOFs, and our experimental results and analysis prove that a layer of MOFs on a separator did enhance the capacity stability. Our results suggest that the chemical stability and the aggregation (packing) morphology of MOF particles play more important roles than the internal cavity size in MOFs.

Apparatus for removing impurities in the sodium of sodium cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Yamauchi, A

1970-11-11

An apparatus is provided for removing oxygen from liquid sodium flowing in a sodium cooled reactor. The removal of oxygen is complete with high efficiency. The liquid sodium to be purified is disposed outside a cylindrical wall and negatively charged, whereas sodium as a reducing material is disposed inside the same wall. The cylindrical wall is made of zirconia-calcia (ZrO/sub 2/)sub(0.87)(CaO)sub(0.13) solid electrolyte, the cylinder having a thickness of 2.5mm, a diameter of 3cm and a depth of 20cm under the sodium level. Electric resistance of the solid electrolyte is 2.3 ohm at 500/sup 0/C. A current of 1A by the application of 25 volts treats 0.3g of oxygen. Consequently, 1 liter or 1kg of liquid sodium containing 1,000ppm of oxygen can be purified for about 3 hours at an electrical consumption of 7.5 watt-hour. In one embodiment, a cylindrical electrolytic solid made of zirconia-calcia or zirconia-yttria was disposed in a container. Liquid sodium containing oxygen flowed outside of the cylinder. Liquid sodium as a reducing material was present inside the cylinder and the container and the cylinder were electrically insulated. An electrode was inserted at the center of the cylinder and a baffle plate at the upper portion of the electrode to shield heat and rising sodium vapor was provided. The space above the container was filled with an inert gas. The oxygen in the liquid sodium to be purified transferred through the wall of the cylinder into the interior of the cylinder so as to oxydize the reducing sodium material. The supersaturated sodium oxide inside the cylinder was deposited.

Nickel Hexacyanoferrate Nanoparticle Electrodes For Aqueous Sodium and Potassium Ion Batteries

KAUST Repository

Wessells, Colin D.

2011-12-14

The electrical power grid faces a growing need for large-scale energy storage over a wide range of time scales due to costly short-term transients, frequency regulation, and load balancing. The durability, high power, energy efficiency, and low cost needed for grid-scale storage pose substantial challenges for conventional battery technology.(1, 2)Here, we demonstrate insertion/extraction of sodium and potassium ions in a low-strain nickel hexacyanoferrate electrode material for at least five thousand deep cycles at high current densities in inexpensive aqueous electrolytes. Its open-framework structure allows retention of 66% of the initial capacity even at a very high (41.7C) rate. At low current densities, its round trip energy efficiency reaches 99%. This low-cost material is readily synthesized in bulk quantities. The long cycle life, high power, good energy efficiency, safety, and inexpensive production method make nickel hexacyanoferrate an attractive candidate for use in large-scale batteries to support the electrical grid. © 2011 American Chemical Society.

An Integrated Glucose Sensor with an All-Solid-State Sodium Ion-Selective Electrode for a Minimally Invasive Glucose Monitoring System

Directory of Open Access Journals (Sweden)

Junko Kojima

2015-06-01

Full Text Available We developed a minimally invasive glucose monitoring system that uses a microneedle to permeate the skin surface and a small hydrogel to accumulate interstitial fluid glucose. The measurement of glucose and sodium ion levels in the hydrogel is required for estimating glucose levels in blood; therefore, we developed a small, enzyme-fixed glucose sensor with a high-selectivity, all-solid-state, sodium ion-selective electrode (ISE integrated into its design. The glucose sensor immobilized glucose oxidase showed a good correlation between the glucose levels in the hydrogels and the reference glucose levels (r > 0.99, and exhibited a good precision (coefficient of variation = 2.9%, 0.6 mg/dL. In the design of the sodium ISEs, we used the insertion material Na0.33MnO2 as the inner contact layer and DD16C5 exhibiting high Na+/K+ selectivity as the ionophore. The developed sodium ISE exhibited high selectivity (\\( \\log \\,k^{pot}_{Na,K} = -2.8\\ and good potential stability. The sodium ISE could measure 0.4 mM (10−3.4 M sodium ion levels in the hydrogels containing 268 mM (10−0.57 M KCl. The small integrated sensor (ϕ < 10 mm detected glucose and sodium ions in hydrogels simultaneously within 1 min, and it exhibited sufficient performance for use as a minimally invasive glucose monitoring system.

Polychlorinated biphenyls in polysulfide sealants-Occurrence and emission from a landfill station

International Nuclear Information System (INIS)

Persson, N. Johan; Pettersen, Harald; Ishaq, Rasha; Axelman, Johan; Bandh, Cecilia; Broman, Dag; Zebuehr, Yngve; Hammar, Tommy

2005-01-01

Approximately 80 000 kg polysulfide sealant containing 10 000-18 000 kg polychlorinated biphenyls (PCB) was deposited at a Swedish municipal landfill station during 1965-1973. Investigations during 1994 showed that soil layers underneath the landfill had concentration of PCB not alarmingly high. The concentration of PCB congeners in ground water samples was elevated 4-750 times compared to a reference sample. Based on samples of ground water, leachate water, and flux chambers measuring evaporation of PCB from the landfill surface, the emission of PCB was estimated to be 1 g ΣPCB/yr. This very low rate was attributed to the high sorptive capacity of the sealant. Compared to a reference site, the evaporation flux was elevated for the most volatile congeners, but factors 20-1400 lower than from another landfill which was contaminated with PCB in paper-pulp fibres. - From a municipal 2-ha landfill containing 10-18 tonnes of ΣPCB bound in polysulfide sealants, only 1 g per year escape to the surroundings

Anionic Redox Chemistry in Polysulfide Electrode Materials for Rechargeable Batteries.

Science.gov (United States)

Grayfer, Ekaterina D; Pazhetnov, Egor M; Kozlova, Mariia N; Artemkina, Sofya B; Fedorov, Vladimir E

2017-12-22

Classical Li-ion battery technology is based on the insertion of lithium ions into cathode materials involving metal (cationic) redox reactions. However, this vision is now being reconsidered, as many new-generation electrode materials with enhanced reversible capacities operate through combined cationic and anionic (non-metal) reversible redox processes or even exclusively through anionic redox transformations. Anionic participation in the redox reactions is observed in materials with more pronounced covalency, which is less typical for oxides, but quite common for phosphides or chalcogenides. In this Concept, we would like to draw the reader's attention to this new idea, especially, as it applies to transition-metal polychalcogenides, such as FeS 2 , VS 4 , TiS 3 , NbS 3 , TiS 4 , MoS 3 , etc., in which the key role is played by the (S-S) 2- /2 S 2- redox reaction. The exploration and better understanding of the anion-driven chemistry is important for designing advanced materials for battery and other energy-related applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesizing Porous NaTi2(PO4)3 Nanoparticles Embedded in 3D Graphene Networks for High-Rate and Long Cycle-Life Sodium Electrodes.

Science.gov (United States)

Wu, Chao; Kopold, Peter; Ding, Yuan-Li; van Aken, Peter A; Maier, Joachim; Yu, Yan

2015-06-23

Sodium ion batteries attract increasing attention for large-scale energy storage as a promising alternative to the lithium counterparts in view of low cost and abundant sodium source. However, the large ion radius of Na brings about a series of challenging thermodynamic and kinetic difficulties to the electrodes for sodium-storage, including low reversible capacity and low ion transport, as well as large volume change. To mitigate or even overcome the kinetic problems, we develop a self-assembly route to a novel architecture consisting of nanosized porous NASICON-type NaTi2(PO4)3 particles embedded in microsized 3D graphene network. Such architecture synergistically combines the advantages of a 3D graphene network and of 0D porous nanoparticles. It greatly increases the electron/ion transport kinetics and assures the electrode structure integrity, leading to attractive electrochemical performance as reflected by a high rate-capability (112 mAh g(-1) at 1C, 105 mAh g(-1) at 5C, 96 mAh g(-1) at 10C, 67 mAh g(-1) at 50C), a long cycle-life (capacity retention of 80% after 1000 cycles at 10C), and a high initial Coulombic efficiency (>79%). This nanostructure design provides a promising pathway for developing high performance NASICON-type materials for sodium storage.

Screen-printed electrode for alkali-metal thermoelectric converter

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, T.; Shibata, K.; Tsuchida, K.; Kato, A. (Kyushu Univ., Fukuoka (Japan). Faculty of Engineering)

1992-06-01

An alkali-metal thermoelectric converter (AMTEC) is a device for the direct conversion of thermal to electric energy. An AMTEC contains sodium as working fluid and is divided into a high-temperature region (900-1300 K) and a low-temperature region (400-800 K) by [beta]''-alumina solid electrolyte. A high-performance electrode for an AMTEC must have good electrical conductivity, make a strong physical bond with low contact resistance to [beta]''-alumina, be highly permeable to sodium vapour, resist corrosion by sodium and have a low rate of evaporation at the operating temperature of the AMTEC. We have previously investigated the interaction of nitrides and carbides of some transition-metals (groups IV, V and VI) with [beta],[beta]''-alumina or liquid sodium (about 700degC) with the objective of finding a better electrode material for an AMTEC. The results showed that TiN, TiC, NbN and NbC were good candidates for AMTEC electrodes. We also showed that porous TiN film with low resistance can be prepared by the screen-printing method. In the present work the porous NbN film was prepared by the screen-printing method and the performance as the electrode of an AMTEC was examined. For comparison, the performance of TiN and Mo electrodes prepared by the screen-printing method was also examined. (author).

Vanadyl phosphates as high energy density cathode materials for rechargeable sodium battery

Science.gov (United States)

Zhang, Ruigang; Mizuno, Fuminori; Ling, Chen; Whittingham, Stanley M.; Zhang, Ruibo; Chen, Zehua

2017-08-01

A positive electrode comprising .epsilon.-VOPO.sub.4 and/or Na.sub.x(.epsilon.-VOPO.sub.4) wherein x is a value from 0.1 to 1.0 as an active ingredient, wherein the electrode is capable of insertion and release of sodium ions and a reversible sodium battery containing the positive electrode are provided.

Shuttle inhibition by chemical adsorption of lithium polysulfides in B and N co-doped graphene for Li-S batteries.

Science.gov (United States)

Li, Fen; Su, Yan; Zhao, Jijun

2016-09-14

The advance of lithium sulfur batteries is now greatly restricted by the fast capacity fading induced by shuttle effect. Using first-principles calculations, various vacancies, N doping, and B,N co-doping in graphene sheets have been systematically explored for lithium polysufides entrapped in Li-S batteries. The LiS, LiC, LiN and SB bonds and Hirshfeld charges in the Li 2 S 6 adsorbed defective graphene systems have been analyzed to understand the intrinsic mechanism of retaining lithium polysulfides in these systems. Total and local densities of states analyses elucidate the strongest adsorption sites among the N and B-N co-doped graphene systems. The overall electrochemical performance of Li-S batteries varies with the types of defects in graphene. Among the defective graphene systems, only the reconstructed pyrrole-like vacancy is effective for retaining lithium polysulfides. N doping induces a strong LiN interaction in the defective graphene systems, in which the pyrrolic N rather than the pyridinic N plays a dominant role in trapping of lithium polysulfides. The shuttle effect can be further depressed via pyrrolic B,N co-doped defective graphene materials, especially the G-B-N-hex system with extremely strong adsorption of lithium polysulfides (4-5 eV), and simultaneous contribution from the strong LiN and SB interactions.

Biomimetic Ant-Nest Electrode Structures for High Sulfur Ratio Lithium-Sulfur Batteries.

Science.gov (United States)

Ai, Guo; Dai, Yiling; Mao, Wenfeng; Zhao, Hui; Fu, Yanbao; Song, Xiangyun; En, Yunfei; Battaglia, Vincent S; Srinivasan, Venkat; Liu, Gao

2016-09-14

The lithium-sulfur (Li-S) rechargeable battery has the benefit of high gravimetric energy density and low cost. Significant research currently focuses on increasing the sulfur loading and sulfur/inactive-materials ratio, to improve life and capacity. Inspired by nature's ant-nest structure, this research results in a novel Li-S electrode that is designed to meet both goals. With only three simple manufacturing-friendly steps, which include slurry ball-milling, doctor-blade-based laminate casting, and the use of the sacrificial method with water to dissolve away table salt, the ant-nest design has been successfully recreated in an Li-S electrode. The efficient capabilities of the ant-nest structure are adopted to facilitate fast ion transportation, sustain polysulfide dissolution, and assist efficient precipitation. High cycling stability in the Li-S batteries, for practical applications, has been achieved with up to 3 mg·cm(-2) sulfur loading. Li-S electrodes with up to a 85% sulfur ratio have also been achieved for the efficient design of this novel ant-nest structure.

First-principles study of mixed eldfellite compounds Nax(Fe1/2M1/2) (SO4)2 (x=0-2, M = Mn, Co, Ni): A new family of high electrode potential cathodes for the sodium-ion battery

Science.gov (United States)

Ri, Gum-Chol; Choe, Song-Hyok; Yu, Chol-Jun

2018-02-01

Natural abundance of sodium and its similar behavior to lithium triggered recent extensive studies of cost-effective sodium-ion batteries (SIBs) for large-scale energy storage systems. A challenge is to develop electrode materials with a high electrode potential, specific capacity and a good rate capability. In this work we propose mixed eldfellite compounds Nax(Fe1/2M1/2) (SO4)2 (x = 0-2, M = Mn, Co, Ni) as a new family of high electrode potential cathodes of SIBs and present their material properties predicted by first-principles calculations. The structural optimizations show that these materials have significantly small volume expansion rates below 5% upon Na insertion/desertion with negative Na binding energies. Through the electronic structure calculations, we find band insulating properties and hole (and/or electron) polaron hoping as a possible mechanism for the charge transfer. Especially we confirm the high electrode voltages over 4 V with reasonably high specific capacities. We also investigate the sodium ion mobility by estimating plausible diffusion pathways and calculating the corresponding activation barriers, demonstrating the reasonably fast migrations of sodium ions during the operation. Our calculation results indicate that these mixed eldfellite compounds can be suitable materials for high performance SIB cathodes.

Insights into the Dual-Electrode Characteristics of Layered Na0.5Ni0.25Mn0.75O2 Materials for Sodium-Ion Batteries.

Science.gov (United States)

Palanisamy, Manikandan; Kim, Hyun Woo; Heo, Seongwoo; Lee, Eungje; Kim, Youngsik

2017-03-29

Sodium-ion batteries are now close to replacing lithium-ion batteries because they provide superior alternative energy storage solutions that are in great demand, particularly for large-scale applications. To that end, the present study is focused on the properties of a new type of dual-electrode material, Na 0.5 Ni 0.25 Mn 0.75 O 2 , synthesized using a mixed hydroxy-carbonate route. Cyclic voltammetry confirms that redox couples, at high and low voltage ranges, are facilitated by the unique features and properties of this dual-electrode, through sodium ion deintercalation/intercalation into the layered Na 0.5 Ni 0.25 Mn 0.75 O 2 material. This material provides superior performance for Na-ion batteries, as evidenced by the fabricated sodium cell that yielded initial charge-discharge capacities of 125/218 mAh g -1 in the voltage range of 1.5-4.4 V at 0.5 C. At a low voltage range (1.5-2.6 V), the anode cell delivered discharge-charge capacities of 100/99 mAh g -1 with 99% capacity retention, which corresponds to highly reversible redox reaction of the Mn 4+/3+ reduction and the Mn 3+/4+ oxidation observed at 1.85 and 2.06 V, respectively. The symmetric Na-ion cell, fabricated using Na 0.5 Ni 0.25 Mn 0.75 O 2 , yielded initial charge-discharge capacities of 196/187 μAh at 107 μA. These results encourage the further development of new types of futuristic sodium-ion-battery-based energy storage systems.

Strong lithium polysulfide chemisorption on electroactive sites of nitrogen-doped carbon composites for high-performance lithium-sulfur battery cathodes.

Science.gov (United States)

Song, Jiangxuan; Gordin, Mikhail L; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; Wang, Donghai

2015-03-27

Despite the high theoretical capacity of lithium-sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g(-1) after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm(-2)) with a high sulfur loading of approximately 5 mg cm(-2), which is ideal for practical applications of the lithium-sulfur batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Connection of indicator of sodium burning in enclosed area

Energy Technology Data Exchange (ETDEWEB)

Enenkl, V

1975-01-15

The connection is described of an indicator of sodium burning in a closed area. The air and combustion product mixture is sucked by a pump through a pipe from the steam generator. Following possible aftercooling it is passed to a hermetically sealed vessel with distilled water. Fitted in the vessel are electrodes wired to a galvanometer. The air-sodium combustion product mixture is directed to the bottom of the vessel and bubbles through the distilled water. Sodium oxide contained in the mixture dissolves in the water and forms an electrolytic solution. The voltage produced at the electrodes may be indicated by the galvanometer.

Boiling enriches the linear polysulfides and the hydrogen sulfide-releasing activity of garlic

NARCIS (Netherlands)

Tocmo, Restituto; Wu, Yuchen; Liang, Dong; Fogliano, Vincenzo; Huang, Dejian

2017-01-01

Garlic is rich in polysulfides, and some of them can be H2S donors. This study was conducted to explore the effect of cooking on garlic's organopolysulfides and H2S-releasing activity. Garlic bulbs were crushed and boiled for a period ranging from 3 to 30 min and the solvent extracts were analyzed

Wustite-based photoelectrodes with lithium, hydrogen, sodium, magnesium, manganese, zinc and nickel additives

Science.gov (United States)

Carter, Emily Ann; Toroker, Maytal Caspary

2017-08-15

A photoelectrode, photovoltaic device and photoelectrochemical cell and methods of making are disclosed. The photoelectrode includes an electrode at least partially formed of FeO combined with at least one of lithium, hydrogen, sodium, magnesium, manganese, zinc, and nickel. The electrode may be doped with at least one of lithium, hydrogen, and sodium. The electrode may be alloyed with at least one of magnesium, manganese, zinc, and nickel.

First principle study of sodium decorated graphyne

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Utpal, E-mail: utpalchemiitkgp@yahoo.com [Assam University, Silchar (India); Bhattacharya, Barnali [Assam University, Silchar (India); Seriani, Nicola [The Abdus Salam ICTP, Trieste (Italy)

2015-11-05

Highlights: • Presence of Na decreases the stability of the system. • Na-decorated graphyne compounds are metallic and might be used in electronics. • The sodium-adsorbed graphyne can be used as electrodes in Na-ion battery. - Abstract: We present first-principles calculations of the electronic properties of Na-decorated graphyne. This structure of the graphyne family is a direct band gap semiconductor with a band gap of 0.44 eV in absence of sodium, but Na-decorated graphyne compounds are metallic, and can then be employed as carbon-based conductors. Metallization is due to charge donation from sodium to carbon. Pristine graphyne is more stable than Na-decorated graphyne, therefore is seems probable that, if this material should be employed as electrode in Na-ion batteries, it would lead to the formation of metallic sodium rather than well dispersed sodium ions. On the other side, this property might be useful if graphyne is employed in water desalination. Finally, the abrupt change from a semiconducting to a metallic state in presence of a small amount of sodium might be exploited in electronics, e.g. for the production of smooth metal–semiconductor interfaces through spatially selective deposition of sodium.

Sulfur‐Limonene Polysulfide: A Material Synthesized Entirely from Industrial By‐Products and Its Use in Removing Toxic Metals from Water and Soil

Science.gov (United States)

Crockett, Michael P.; Evans, Austin M.; Worthington, Max J. H.; Albuquerque, Inês S.; Slattery, Ashley D.; Gibson, Christopher T.; Campbell, Jonathan A.; Lewis, David A.; Bernardes, Gonçalo J. L.

2015-01-01

Abstract A polysulfide material was synthesized by the direct reaction of sulfur and d‐limonene, by‐products of the petroleum and citrus industries, respectively. The resulting material was processed into functional coatings or molded into solid devices for the removal of palladium and mercury salts from water and soil. The binding of mercury(II) to the sulfur‐limonene polysulfide resulted in a color change. These properties motivate application in next‐generation environmental remediation and mercury sensing. PMID:26481099

Dual functional MoS2/graphene interlayer as an efficient polysulfide barrier for advanced lithium-sulfur batteries

International Nuclear Information System (INIS)

Guo, Pengqian; Liu, Dequan; Liu, Zhengjiao; Shang, Xiaonan; Liu, Qiming; He, Deyan

2017-01-01

Highlights: •Dual functional MoS 2 /graphene interlayer was first used as an efficient polysulfide-trapping shield for lithium-sulfur batteries. •MoS 2 /graphene interlayer shows strong chemical interactions with LiPSs. •MoS 2 /graphene interlayer forms a 3D network to facilitate electron and ion transfer during the discharge-charge processes. •The resultant lithium-sulfur batteries exhibit a superior rate capacity and improved cycling capacity. -- Abstract: A dual functional interlayer consisted of composited two-dimensional MoS 2 and graphene has been developed as an efficient polysulfide barrier for lithium-sulfur batteries (LSBs). With such a configuration, LSBs show a superior rate capacity and improved cycling capacity. The excellent electrochemical performance can be attributed to the strong bonding interactions between the MoS 2 /graphene interlayer and the formed lithium polysulfides (LiPSs) as well as the good electrical conductivity of the MoS 2 /graphene composite. The MoS 2 /graphene interlayer can physically block LiPSs by the graphene nanosheets and chemically suppress the dissolution of LiPSs by the polar MoS 2 nanoflowers. Such a dual functional interlayer further provides a good contact with the surface of the sulfur cathode, acts as an upper current collector and greatly improves the sulfur utilization and the rate capability of LSBs.

Carbon felt interlayer derived from rice paper and its synergistic encapsulation of polysulfides for lithium-sulfur batteries

Science.gov (United States)

Yang, Kai; Zhong, Lei; Guan, Ruiteng; Xiao, Min; Han, Dongmei; Wang, Shuanjin; Meng, Yuezhong

2018-05-01

Lithium-sulfur (Li-S) batteries have remarkably high theoretical specific capacity as promising candidates for next-generation energy storage. However, the "polysulfides shuttle" effect hampers its commercial application. Here, we use a kind of rice paper as a raw material to get inorganic oxides doping carbon felt by the facile carbonization method, and then modified by a simple coating process using poly (fluorenyl ether ketone) and Super P slurry. The special structure of the carbon felt derived from rice paper and its modified layer endow the final electronic conductive interlayer with inherent polysulfides absorbents and ion Coulombic repulsion functions, respectively, which show synergistic effect for trapping polysulfides. As an interlayer of Li-S batteries, the obtained carbon felt/poly (fluorenyl ether ketone)& Super P (CFSS) interlayer shows excellent electrochemical performance in improving specific capacity and decreasing polarization. The batteries with CFSS interlayer exhibit a high capacity of 837 mA h g-1 at 2.0 C and a high initial capacity of 1073.4 mA h g-1 and good capacity retention of 824.5 mA h g-1 after 500 cycles at 0.5 C. CFSS interlayer also shows excellent anti-self-discharge performance. Therefore, the simple and economical CFSS interlayer can be considered as a promising component for high performance Li-S batteries.

Selective sodium intercalation into sodium nickel-manganese sulfate for dual Na-Li-ion batteries.

Science.gov (United States)

Marinova, Delyana M; Kukeva, Rosica R; Zhecheva, Ekaterina N; Stoyanova, Radostina K

2018-04-26

Double sodium transition metal sulfates combine in themselves unique intercalation properties with eco-compatible compositions - a specific feature that makes them attractive electrode materials for lithium and sodium ion batteries. Herein, we examine the intercalation properties of novel double sodium nickel-manganese sulfate, Na2Ni1/2Mn1/2(SO4)2, having a large monoclinic unit cell, through electrochemical and ex situ diffraction and spectroscopic methods. The sulfate salt Na2Ni1/2Mn1/2(SO4)2 is prepared by thermal dehydration of the corresponding hydrate salt Na2Ni1/2Mn1/2(SO4)2·4H2O having a blödite structure. The intercalation reactions on Na2Ni1-xMnx(SO4)2 are studied in two model cells: half-ion cell versus Li metal anode and full-ion cell versus Li4Ti5O12 anode by using lithium (LiPF6 dissolved in EC/DMC) and sodium electrolytes (NaPF6 dissolved in EC:DEC). Based on ex situ XRD and TEM analysis, it is found that sodium intercalation into Na2Ni1/2Mn1/2(SO4)2 takes place via phase separation into the Ni-rich monoclinic phase and Mn-rich alluaudite phase. The redox reactions involving participation of manganese and titanium ions are monitored by ex situ EPR spectroscopy. It has been demonstrated that manganese ions from the sulfate salt are participating in the electrochemical reaction, while the nickel ions remain intact. As a result, a reversible capacity of about 65 mA h g-1 is reached. The selective intercalation properties determine sodium nickel-manganese sulfate as a new electrode material for hybrid lithium-sodium ion batteries that is thought to combine the advantages of individual lithium and sodium batteries.

Facile Synthesis of Monodispersed Polysulfide Spheres for Building Structural Colors with High Color Visibility and Broad Viewing Angle.

Science.gov (United States)

Li, Feihu; Tang, Bingtao; Wu, Suli; Zhang, Shufen

2017-01-01

The synthesis and assembly of monodispersed colloidal spheres are currently the subject of extensive investigation to fabricate artificial structural color materials. However, artificial structural colors from general colloidal crystals still suffer from the low color visibility and strong viewing angle dependence which seriously hinder their practical application in paints, colorimetric sensors, and color displays. Herein, monodispersed polysulfide (PSF) spheres with intrinsic high refractive index (as high as 1.858) and light-absorbing characteristics are designed, synthesized through a facile polycondensation and crosslinking process between sodium disulfide and 1,2,3-trichloropropane. Owing to their high monodispersity, sufficient surface charge, and good dispersion stability, the PSF spheres can be assembled into large-scale and high-quality 3D photonic crystals. More importantly, high structural color visibility and broad viewing angle are easily achieved because the unique features of PSF can remarkably enhance the relative reflectivity and eliminate the disturbance of scattering and background light. The results of this study provide a simple and efficient strategy to create structural colors with high color visibility, which is very important for their practical application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

Science.gov (United States)

Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

2006-01-01

This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

Biomass-derived porous carbon modified glass fiber separator as polysulfide reservoir for Li-S batteries.

Science.gov (United States)

Selvan, Ramakrishnan Kalai; Zhu, Pei; Yan, Chaoi; Zhu, Jiadeng; Dirican, Mahmut; Shanmugavani, A; Lee, Yun Sung; Zhang, Xiangwu

2018-03-01

Biomass-derived porous carbon has been considered as a promising sulfur host material for lithium-sulfur batteries because of its high conductive nature and large porosity. The present study explored biomass-derived porous carbon as polysulfide reservoir to modify the surface of glass fiber (GF) separator. Two different carbons were prepared from Oak Tree fruit shells by carbonization with and without KOH activation. The KOH activated porous carbon (AC) provides a much higher surface area (796 m 2  g -1 ) than pyrolized carbon (PC) (334 m 2  g -1 ). The R factor value, calculated from the X-ray diffraction pattern, revealed that the activated porous carbon contains more single-layer sheets with a lower degree of graphitization. Raman spectra also confirmed the presence of sp 3 -hybridized carbon in the activated carbon structure. The COH functional group was identified through X-ray photoelectron spectroscopy for the polysulfide capture. Simple and straightforward coating of biomass-derived porous carbon onto the GF separator led to an improved electrochemical performance in Li-S cells. The Li-S cell assembled with porous carbon modified GF separator (ACGF) demonstrated an initial capacity of 1324 mAh g -1 at 0.2 C, which was 875 mAh g -1 for uncoated GF separator (calculated based on the 2nd cycle). Charge transfer resistance (R ct ) values further confirmed the high ionic conductivity nature of porous carbon modified separators. Overall, the biomass-derived activated porous carbon can be considered as a promising alternative material for the polysulfide inhibition in Li-S batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

Coordination Polymer Modified Separator for Mitigating Polysulfide Shuttle Effect in Lithium-Sulfur Batteries

KAUST Repository

Wan, Yi

2017-11-19

The development of the new cathode and anode materials of Lithium-Ion Batteries (LIBs) with high energy density and outstanding electrochemical performance is of substantial technological importance due to the ever-increasing demand for economic and efficient energy storage system. Because of the abundance of element sulfur and high theoretical energy density, Lithium-Sulfur (Li-S) batteries have become one of the most promising candidates for the next-generation energy storage system. However, the shuttling effect of electrolyte-soluble polysulfides severely impedes the cell performance and commercialization of Li-S batteries, and significant progress have been made to mitigate this shuttle effect in the past two decades. Coordination polymers (CPs) or Metal-organic Frameworks (MOFs) have been attracted much attention by virtue of their controllable porosity, nanometer cavity sizes and high surface areas, which supposed to be an available material in suppressing polysulfide migration. In this thesis, we investigate different mechanisms of mitigating polysulfide diffusion by applying a layer of MOFs (including Y-FTZB, ZIF-7, ZIF-8, and HKUST-1) on a separator. We also fabricate a new free-standing 2D coordination polymer Zn2(Benzimidazolate)2(OH)2 with rich hydroxyl (OH-) groups by using a simple, scalable and low cost method at air/water surface. Our results suggest that the chemical stability, the cluster morphology and the surface function groups of MOFs shows a greater impact on minimizing the shuttling effect in Li-S batteries, other than the internal cavity size in MOFs. Meanwhile, the new design of 2D coordination polymer efficiently mitigate the shuttling effect in Li-S battery resulting in a largely promotion of the battery capacity to 1407 mAh g-1 at 0.1 C and excellent cycling performance (capacity retention of 98% after 200 cycles at 0.25C). Such excellent cell performance is mainly owing to the fancying physical and chemical structure controllability

Advanced materials for sodium-beta alumina batteries: Status, challenges and perspectives

Science.gov (United States)

Lu, Xiaochuan; Xia, Guanguang; Lemmon, John P.; Yang, Zhenguo

The increasing penetration of renewable energy and the trend toward clean, efficient transportation have spurred growing interests in sodium-beta alumina batteries that store electrical energy via sodium ion transport across a β″-Al 2O 3 solid electrolyte at elevated temperatures (typically 300-350 °C). Currently, the negative electrode or anode is metallic sodium in molten state during battery operation; the positive electrode or cathode can be molten sulfur (Na-S battery) or solid transition metal halides plus a liquid phase secondary electrolyte (e.g., ZEBRA battery). Since the groundbreaking works in the sodium-beta alumina batteries a few decades ago, encouraging progress has been achieved in improving battery performance, along with cost reduction. However, there remain issues that hinder broad applications and market penetration of the technologies. To better the Na-beta alumina technologies require further advancement in materials along with component and system design and engineering. This paper offers a comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement.

Advanced materials for sodium-beta alumina batteries: Status, challenges and perspectives

International Nuclear Information System (INIS)

Lu, Xiaochuan; Xia, Guanguang; Lemmon, John P.; Yang, Zhenguo

2010-01-01

The increasing penetration of renewable energy and the trend toward clean, efficient transportation have spurred growing interests in sodium-beta alumina batteries that store electrical energy via sodium ion transport across a β''-Al 2 O 3 solid electrolyte at elevated temperatures (typically 300-350 C). Currently, the negative electrode or anode is metallic sodium in molten state during battery operation; the positive electrode or cathode can be molten sulfur (Na-S battery) or solid transition metal halides plus a liquid phase secondary electrolyte (e.g., ZEBRA battery). Since the groundbreaking works in the sodium-beta alumina batteries a few decades ago, encouraging progress has been achieved in improving battery performance, along with cost reduction. However, there remain issues that hinder broad applications and market penetration of the technologies. To better the Na-beta alumina technologies require further advancement in materials along with component and system design and engineering. This paper offers a comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement. (author)

Quantitative analysis of lead in polysulfide-based impression material

Directory of Open Access Journals (Sweden)

Aparecida Silva Braga

2007-06-01

Full Text Available Permlastic® is a polysulfide-based impression material widely used by dentists in Brazil. It is composed of a base paste and a catalyzer containing lead dioxide. The high toxicity of lead to humans is ground for much concern, since it can attack various systems and organs. The present study involved a quantitative analysis of the concentration of lead in the material Permlastic®. The lead was determined by plasma-induced optical emission spectrometry (Varian model Vista. The percentages of lead found in the two analyzed lots were 38.1 and 40.8%. The lead concentrations in the material under study were high, but the product’s packaging contained no information about these concentrations.

Improving the capacity of lithium-sulfur batteries by tailoring the polysulfide adsorption efficiency of hierarchical oxygen/nitrogen-functionalized carbon host materials.

Science.gov (United States)

Schneider, Artur; Janek, Jürgen; Brezesinski, Torsten

2017-03-22

The use of monolithic carbons with structural hierarchy and varying amounts of nitrogen and oxygen functionalities as sulfur host materials in high-loading lithium-sulfur cells is reported. The primary focus is on the strength of the polysulfide/carbon interaction with the goal of assessing the effect of (surface) dopant concentration on cathode performance. The adsorption capacity - which is a measure of the interaction strength between the intermediate lithium polysulfide species and the carbon - was found to scale almost linearly with the nitrogen level. Likewise, the discharge capacity of lithium-sulfur cells increased linearly. This positive correlation can be explained by the favorable effect of nitrogen on both the chemical and electronic properties of the carbon host. The incorporation of additional oxygen-containing surface groups into highly nitrogen-functionalized carbon helped to further enhance the polysulfide adsorption efficiency, and therefore the reversible cell capacity. Overall, the areal capacity could be increased by almost 70% to around 3 mA h cm -2 . We believe that the design parameters described here provide a blueprint for future carbon-based nanocomposites for high-performance lithium-sulfur cells.

High-Performance Lithium-Sulfur Batteries with a Self-Assembled Multiwall Carbon Nanotube Interlayer and a Robust Electrode-Electrolyte Interface.

Science.gov (United States)

Kim, Hee Min; Hwang, Jang-Yeon; Manthiram, Arumugam; Sun, Yang-Kook

2016-01-13

Elemental sulfur electrode has a huge advantage in terms of charge-storage capacity. However, the lack of electrical conductivity results in poor electrochemical utilization of sulfur and performance. This problem has been overcome to some extent previously by using a bare multiwall carbon nanotube (MWCNT) paper interlayer between the sulfur cathode and the polymeric separator, resulting in good electron transport and adsorption of dissolved polysulfides. To advance the interlayer concept further, we present here a self-assembled MWCNT interlayer fabricated by a facile, low-cost process. The Li-S cells fabricated with the self-assembled MWCNT interlayer and a high loading of 3 mg cm(-2) sulfur exhibit a first discharge specific capacity of 1112 mAh g(-1) at 0.1 C rate and retain 95.8% of the capacity at 0.5 C rate after 100 cycles as the self-assembled MWCNT interlayer facilitates good interfacial contact between the interlayer and the sulfur cathode and fast electron and lithium-ion transport while trapping and reutilizing the migrating polysulfides. The approach presented here has the potential to advance the commercialization feasibility of the Li-S batteries.

Diallyl Polysulfides from Allium sativum as Immunomodulators, Hepatoprotectors, and Antimycobacterial Agents.

Science.gov (United States)

Oosthuizen, Carel; Arbach, Miriam; Meyer, Debra; Hamilton, Chris; Lall, Namrita

2017-07-01

Mycobacterium tuberculosis remains one of the world's deadliest killers, with an annual death rate of ∼1.5 million. The medicinal effects of garlic have been well documented, and natural products have been shown to have antimycobacterial activity. The current study evaluated the efficacy of six Allium sativum L. polysulfide mixtures as antimycobacterial agents together with their cytotoxic, immunomodulatory, and hepatoprotective activities. The microtitre PrestoBlue assay was used to determine the minimum inhibitory concentrations (MIC). Cytotoxicity was evaluated by using peripheral blood mononuclear cells (PBMC). Excreted cytokine levels were determined by utilizing an enzyme-linked immunosorbent assay (ELISA), by exposing isolated PBMCs to varying concentrations of polysulfide mixtures. Human C3A liver cells were utilized in the hepatoprotective study, to assess the protective effect against the toxicity induced by acetaminophen. Samples with higher amounts of diallyl trisulfide (Sample G4) showed the highest antimycobacterial activity, exhibiting an MIC of 2.5 μg/mL against M. tuberculosis H37Rv. Five samples showed moderate toxicity in PBMC, with G1 showing no toxicity. The selective index of G4 was the highest, with a selectivity index close to one. Two samples, G3 and G6 containing higher amounts of diallyl tetrasulfide and lower amounts of diallyl trisulfide, showed >50% hepatoprotection. This is comparable to a hepatoprotective agent, Silymarin, which showed a hepatoprotective effect of 30% at the tested concentration. Diallyl tetrasulfide showed significant antimycobacterial activity. A combination of higher diallyl tetrasulfide and lower diallyl trisulfide was indicative of hepatoprotective activity.

From Lithium-Ion to Sodium-Ion Batteries: Advantages, Challenges, and Surprises.

Science.gov (United States)

Nayak, Prasant Kumar; Yang, Liangtao; Brehm, Wolfgang; Adelhelm, Philipp

2018-01-02

Mobile and stationary energy storage by rechargeable batteries is a topic of broad societal and economical relevance. Lithium-ion battery (LIB) technology is at the forefront of the development, but a massively growing market will likely put severe pressure on resources and supply chains. Recently, sodium-ion batteries (SIBs) have been reconsidered with the aim of providing a lower-cost alternative that is less susceptible to resource and supply risks. On paper, the replacement of lithium by sodium in a battery seems straightforward at first, but unpredictable surprises are often found in practice. What happens when replacing lithium by sodium in electrode reactions? This review provides a state-of-the art overview on the redox behavior of materials when used as electrodes in lithium-ion and sodium-ion batteries, respectively. Advantages and challenges related to the use of sodium instead of lithium are discussed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sodium monitoring in the water and steam cycle of power plants

Energy Technology Data Exchange (ETDEWEB)

Dudouit, P. [Ecole Nationale Superieure d' Electricite et de Mecanique, Nancy (France); Guillou, P.; Hostis, E. l' [Hach Ultra Analytics SA, Vesenaz (Switzerland)

2006-11-15

Today sodium concentration has become one of the most important indexes for quality control of water and steam at power plants; however, measurement of this parameter can be difficult in practice. The use of ion selective electrodes means that analyzers are sensitive to pH shifts, and constant exposure to very low concentrations of sodium ions in ultrapure water conditions can lead to electrode desensitization. In addition, there is a need to address drift through regular calibration. This paper discusses the technical challenges in low level sodium analysis and the required features for a practical and accurate analyzer to provide trouble free, sub {mu}g.kg{sup -1} (sub ppb) measurement. (orig.)

Alkali metal-refractory metal biphase electrode for AMTEC

Science.gov (United States)

Williams, Roger M. (Inventor); Bankston, Clyde P. (Inventor); Cole, Terry (Inventor); Khanna, Satish K. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Wheeler, Bob L. (Inventor)

1989-01-01

An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.

High-pressure sodium lamp

NARCIS (Netherlands)

1996-01-01

A high pressure sodium lamp of the invention is provided with a discharge vessel (20) which is enclosed with intervening space (1) by an outer bulb (10), which space contains a gas-fill with at least 70 mol. % nitrogen gas. Electrodes (30a, 30b) are positioned in the discharge vessel (20) and are

The re-emergence of sodium ion batteries: testing, processing, and manufacturability

Science.gov (United States)

Roberts, Samuel; Kendrick, Emma

2018-01-01

With the re-emergence of sodium ion batteries (NIBs), we discuss the reasons for the recent interests in this technology and discuss the synergies between lithium ion battery (LIB) and NIB technologies and the potential for NIB as a “drop-in” technology for LIB manufacturing. The electrochemical testing of sodium materials in sodium metal anode arrangements is reviewed. The performance, stability, and polarization of the sodium in these test cells lead to alternative testing in three-electrode and alternative anode cell configurations. NIB manufacturability is also discussed, together with the impact that the material stability has upon the electrodes and coating. Finally, full-cell NIB technologies are reviewed, and literature proof-of-concept cells give an idea of some of the key differences in the testing protocols of these batteries. For more commercially relevant formats, safety, passive voltage control through cell balancing and cell formation aspects are discussed. PMID:29910609

Electro-oxidation of chlorophenols on poly(3,4-ethylenedioxythiophene)-poly(styrene sulphonate) composite electrode

International Nuclear Information System (INIS)

Pigani, L.; Musiani, M.; Pirvu, C.; Terzi, F.; Zanardi, C.; Seeber, R.

2007-01-01

The electrochemical behaviour of chlorinated phenols on Pt/poly(3,4-ethylenedioxy)thiophene,LiClO 4 and on Pt/poly(3,4-ethylenedioxy)thiophene,poly(sodium-4-styrenesulphonate) electrodes has been investigated in phosphate buffer solution. Poly(sodium-4-styrenesulphonate) exerts remarkable effect against the electrode fouling induced by oxidation of chlorophenols, allowing us to record the relevant anodic response even after repeated potential cycles. Hypotheses about the role exerted by poly(sodium 4-styrenesulphonate) are made, on the basis of evidences provided by several techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, electrochemical microgravimetry and atomic force microscopy. Thanks to the fact that different chlorophenols show differences in the voltammetric responses, depending on number and position of the chloro substituents on the aromatic ring, applications of the modified electrode in the analysis of mixtures of chlorinated phenols are possible

A high-capacity, low-cost layered sodium manganese oxide material as cathode for sodium-ion batteries.

Science.gov (United States)

Guo, Shaohua; Yu, Haijun; Jian, Zelang; Liu, Pan; Zhu, Yanbei; Guo, Xianwei; Chen, Mingwei; Ishida, Masayoshi; Zhou, Haoshen

2014-08-01

A layered sodium manganese oxide material (NaMn3 O5 ) is introduced as a novel cathode materials for sodium-ion batteries. Structural characterizations reveal a typical Birnessite structure with lamellar stacking of the synthetic nanosheets. Electrochemical tests reveal a particularly large discharge capacity of 219 mAh g(-1) in the voltage rang of 1.5-4.7 V vs. Na/Na(+) . With an average potential of 2.75 V versus sodium metal, layered NaMn3 O5 exhibits a high energy density of 602 Wh kg(-1) , and also presents good rate capability. Furthermore, the diffusion coefficient of sodium ions in the layered NaMn3 O5 electrode is investigated by using the galvanostatic intermittent titration technique. The results greatly contribute to the development of room-temperature sodium-ion batteries based on earth-abundant elements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemistry of sulfur and polysulfides in ionic liquids.

Science.gov (United States)

Manan, Ninie S A; Aldous, Leigh; Alias, Yatimah; Murray, Paul; Yellowlees, Lesley J; Lagunas, M Cristina; Hardacre, Christopher

2011-12-01

The electrochemistry of elemental sulfur (S(8)) and the polysulfides Na(2)S(4) and Na(2)S(6) has been studied for the first time in nonchloroaluminate ionic liquids. The cyclic voltammetry of S(8) in the ionic liquids is different to the behavior reported in some organic solvents, with two reductions and one oxidation peak observed. Supported by in situ UV-vis spectro-electrochemical experiments, the main reduction products of S(8) in [C(4)mim][DCA] ([C(4)mim] = 1-butyl-3-methylimidazolium; DCA = dicyanamide) have been identified as S(6)(2-) and S(4)(2-), and plausible pathways for the formation of these species are proposed. Dissociation and/or disproportionation of the polyanions S(6)(2-) and S(4)(2-) appears to be slow in the ionic liquid, with only small amounts of the blue radical species S(3)(•-) formed in the solutions at r.t., in contrast with that observed in most molecular solvents. © 2011 American Chemical Society

High Electrocatalytic Activity of Vertically Aligned Single-Walled Carbon Nanotubes towards Sulfide Redox Shuttles.

Science.gov (United States)

Hao, Feng; Dong, Pei; Zhang, Jing; Zhang, Yongchang; Loya, Phillip E; Hauge, Robert H; Li, Jianbao; Lou, Jun; Lin, Hong

2012-01-01

Vertically aligned single-walled carbon nanotubes (VASWCNTs) have been successfully transferred onto transparent conducting oxide glass and implemented as efficient low-cost, platinum-free counter electrode in sulfide -mediated dye-sensitized solar cells (DSCs), featuring notably improved electrocatalytic activity toward thiolate/disulfide redox shuttle over conventional Pt counter electrodes. Impressively, device with VASWCNTs counter electrode demonstrates a high fill factor of 0.68 and power conversion efficiency up to 5.25%, which is significantly higher than 0.56 and 3.49% for that with a conventional Pt electrode. Moreover, VASWCNTs counter electrode produces a charge transfer resistance of only 21.22 Ω towards aqueous polysulfide electrolyte commonly applied in quantum dots-sensitized solar cells (QDSCs), which is several orders of magnitude lower than that of a typical Pt electrode. Therefore, VASWCNTs counter electrodes are believed to be a versatile candidate for further improvement of the power conversion efficiency of other iodine-free redox couple based DSCs and polysulfide electrolyte based QDSCs.

Role of Transient Receptor Potential Ankyrin 1 Ion Channel and Somatostatin sst4 Receptor in the Antinociceptive and Anti-inflammatory Effects of Sodium Polysulfide and Dimethyl Trisulfide

Directory of Open Access Journals (Sweden)

István Z. Bátai

2018-02-01

Full Text Available Transient receptor potential ankyrin 1 (TRPA1 non-selective ligand-gated cation channels are mostly expressed in primary sensory neurons. Polysulfides (POLYs are Janus-faced substances interacting with numerous target proteins and associated with both protective and detrimental processes. Activation of TRPA1 in sensory neurons, consequent somatostatin (SOM liberation and action on sst4 receptors have recently emerged as mediators of the antinociceptive effect of organic trisulfide dimethyl trisulfide (DMTS. In the frame of the present study, we set out to compare the participation of this mechanism in antinociceptive and anti-inflammatory effects of inorganic sodium POLY and DMTS in carrageenan-evoked hind-paw inflammation. Inflammation of murine hind paws was induced by intraplantar injection of carrageenan (3% in 30 µL saline. Animals were treated intraperitoneally with POLY (17 µmol/kg or DMTS (250 µmol/kg or their respective vehicles 30 min prior paw challenge and six times afterward every 60 min. Mechanical pain threshold and swelling of the paws were measured by dynamic plantar aesthesiometry and plethysmometry at 2, 4, and 6 h after initiation of inflammation. Myeloperoxidase (MPO activity in the hind paws were detected 6 h after challenge by luminescent imaging. Mice genetically lacking TRPA1 ion channels, sst4 receptors and their wild-type counterparts were used to examine the participation of these proteins in POLY and DMTS effects. POLY counteracted carrageenan-evoked mechanical hyperalgesia in a TRPA1 and sst4 receptor-dependent manner. POLY did not influence paw swelling and MPO activity. DMTS ameliorated all examined inflammatory parameters. Mitigation of mechanical hyperalgesia and paw swelling by DMTS were mediated through sst4 receptors. These effects were present in TRPA1 knockout animals, too. DMTS inhibited MPO activity with no participation of the sensory neuron–SOM axis. While antinociceptive effects of

Stabilization of cadmium electrode properties when introducing surfactants

International Nuclear Information System (INIS)

Alekseeva, M.E.; Mansurov, F.Kh.; Nikol'skij, V.A.

1995-01-01

The results of tests of both separate cadmium electrodes and silver-cadmium accumulators, depending on introduction of surfactants (polyethylene oxide - PO - and its derivatives), have been considered. The influence of PO on the course of electrochemical reaction on cadmium is pronounced in facilitation of anodic process. In case of PO introduction in the amount of 1 % instead of sodium lignosulfonate (2 %) into accumulators with silver-cadmium electrodes, the electrode potential is stabilized, while the accumulator capacity increases. The time period of the accumulation maintenance in the charged state increases 2-3 fold (1-1,5 years). 5 refs.; 4 figs.; 2 tabs

Simultaneous Formation of Artificial SEI Film and 3D Host for Stable Metallic Sodium Anodes.

Science.gov (United States)

Zhang, Di; Li, Bin; Wang, Shuai; Yang, Shubin

2017-11-22

Metallic sodium is a promising anode for sodium-based batteries, owing to its high theoretical capacity (1165 mAh g -1 ) and low potential (-2.714 V vs standard hydrogen electrode). However, the growth of sodium dendrites and the infinite volume change of metallic sodium during sodium striping/plating result in a low Coulombic efficiency and poor cycling stability, generating a safety hazard of sodium-based batteries. Here, an efficient approach was proposed to simultaneously generate an artificial SEI film and 3D host for metallic sodium based on a conversion reaction (CR) between sodium and MoS 2 (4Na + MoS 2 = 2Na 2 S + Mo) at room temperature. In the resultant sodium-MoS 2 hybrid after the conversion reaction (Na-MoS 2 (CR)), the production Na 2 S is homogeneously dispersed on the surface of metallic sodium, which can act as an artificial SEI film, efficiently preventing the growth of sodium dendrites; the residual MoS 2 nanosheets can construct a 3D host to confine metallic sodium, accommodating largely the volume change of sodium. Consequently, the Na-MoS 2 (CR) hybrid exhibits very low overpotential of 25 mV and a very long cycle stability more than 1000 cycles. This novel strategy is promising to promote the development of metal (lithium, sodium, zinc)-based electrodes.

X-ray absorption spectroscopy of ultramarine pigments: A new analytical method for the polysulfide radical anion S3- chromophore

International Nuclear Information System (INIS)

Fleet, Michael E.; Liu, Xi

2010-01-01

Blue and mauve ultramarine artists' pigments and their heat-treated products have been investigated by sulfur K-edge X-ray absorption. X-ray absorption near-edge structure spectra are dominated by features of reduced sulfur and sulfate species. There is also a pre-peak at about 2468.0 eV which reflects the presence of the unpaired electron on the polysulfide radical anion (S 3 - ). Pre-peak intensity is directly proportional to the depth of blue coloration, and provides a new, independent method for estimating the proportion of ultramarine cage sites occupied by the blue chromophore. The occupancy of the polysulfide radical anion S 3 - is estimated to be 33% in an intense ultramarine blue pigment, 22% in a dark blue ultramarine pigment, and 1% in deep royal blue lazurite from Afghanistan. The more efficient development of color in lazurite is attributed to extensive annealing of the mineral structure in the natural environment.

Crystalline maricite NaFePO4 as a positive electrode material for sodium secondary batteries operating at intermediate temperature

Science.gov (United States)

Hwang, Jinkwang; Matsumoto, Kazuhiko; Orikasa, Yuki; Katayama, Misaki; Inada, Yasuhiro; Nohira, Toshiyuki; Hagiwara, Rika

2018-02-01

Maricite NaFePO4 (m-NaFePO4) was investigated as a positive electrode material for intermediate-temperature operation of sodium secondary batteries using ionic liquid electrolytes. Powdered m-NaFePO4 was prepared by a conventional solid-state method at 873 K and subsequently fabricated in two different conditions; one is ball-milled in acetone and the other is re-calcined at 873 K after the ball-milling. Electrochemical properties of the electrodes prepared with the as-synthesized m-NaFePO4, the ball-milled m-NaFePO4, and the re-calcined m-NaFePO4 were investigated in Na[FSA]-[C2C1im][FSA] (C2C1im+ = 1-ethyl-3-methylimidazolium, FSA- = bis(fluorosulfonyl)amide) ionic liquid electrolytes at 298 K and 363 K to assess the effects of temperature and particle size on their electrochemical properties. A reversible charge-discharge capacity of 107 mAh g-1 was achieved with a coulombic efficiency >98% from the 2nd cycle using the ball-milled m-NaFePO4 electrode at a C-rate of 0.1 C and 363 K. Electrochemical impedance spectroscopy using m-NaFePO4/m-NaFePO4 symmetric cells indicated that inactive m-NaFePO4 becomes an active material through ball-milling treatment and elevation of operating temperature. X-ray diffraction analysis of crystalline m-NaFePO4 confirmed the lattice contraction and expansion upon charging and discharging, respectively. These results indicate that the desodiation-sodiation process in m-NaFePO4 is reversible in the intermediate-temperature range.

High-alkali low-temperature polysulfide pulping (HALT) of Scots pine.

Science.gov (United States)

Paananen, Markus; Sixta, Herbert

2015-10-01

High-alkali low-temperature polysulfide pulping (HALT) was effectively utilised to prevent major polysaccharide losses while maintaining the delignification rate. A yield increase of 6.7 wt% on wood was observed for a HALT pulp compared to a conventionally produced kappa number 60 pulp with comparable viscosity. Approximately 70% of the yield increase was attributed to improved galactoglucomannan preservation and 30% to cellulose. A two-stage oxygen delignification sequence with inter-stage peroxymonosulphuric acid treatment was used to ensure delignification to a bleachable grade. In a comparison to conventional pulp, HALT pulp effectively maintained its yield advantage. Diafiltration trials indicate that purified black liquor can be directly recycled, as large lignin fractions and basically all dissolved polysaccharides were separated from the alkali-rich BL. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluoroethylene Carbonate-Based Electrolyte with 1 M Sodium Bis(fluorosulfonyl)imide Enables High-Performance Sodium Metal Electrodes.

Science.gov (United States)

Lee, Yongwon; Lee, Jaegi; Lee, Jeongmin; Kim, Koeun; Cha, Aming; Kang, Sujin; Wi, Taeung; Kang, Seok Ju; Lee, Hyun-Wook; Choi, Nam-Soon

2018-05-02

Sodium (Na) metal anodes with stable electrochemical cycling have attracted widespread attention because of their highest specific capacity and lowest potential among anode materials for Na batteries. The main challenges associated with Na metal anodes are dendritic formation and the low density of deposited Na during electrochemical plating. Here, we demonstrate a fluoroethylene carbonate (FEC)-based electrolyte with 1 M sodium bis(fluorosulfonyl)imide (NaFSI) salt for the stable and dense deposition of the Na metal during electrochemical cycling. The novel electrolyte combination developed here circumvents the dendritic Na deposition that is one of the primary concerns for battery safety and constructs the uniform ionic interlayer achieving highly reversible Na plating/stripping reactions. The FEC-NaFSI constructs the mechanically strong and ion-permeable interlayer containing NaF and ionic compounds such as Na 2 CO 3 and sodium alkylcarbonates.

Carbon coated anatase TiO2 mesocrystals enabling ultrastable and robust sodium storage

Science.gov (United States)

Zhang, Weifeng; Lan, Tongbin; Ding, Tianli; Wu, Nae-Lih; Wei, Mingdeng

2017-08-01

Nanoporous anatase TiO2 mesocrystals with tunable architectures and crystalline phases were successfully fabricated in the presence of the butyl oleate and oleylamine. Especially, the introduced surfactants served as a carbon source, bring a uniform carbon layer (about 2-8 nm) for heightening the electronic conductivity. The carbon coated TiO2 mesocrystals assembled from crystalline tiny subunits have more space sites for sodium-ion storage. When the material was applied as an electrode material in rechargeable sodium-ion batteries, it exhibited a superior capacity of about 90 mA h g-1 at 20 C (1 C = 168 mA g-1) and a highly reversible capacity for 5000 cycles, which is the longest cycle life reported for sodium storage in TiO2 electrodes.

Analysis on the effect of polysulfide electrolyte composition for higher performance of Si quantum dot-sensitized solar cells

International Nuclear Information System (INIS)

Seo, Hyunwoong; Wang, Yuting; Uchida, Giichiro; Kamataki, Kunihiro; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

2013-01-01

Quantum dot-sensitized solar cell (QDSC) based on multiple exciton generation of QD has been expected to realize high efficiency. This work focused on Si QD instead of conventional QD materials because of their toxicity and scarcity. Si QDs were fabricated by multi-hollow discharge plasma chemical vapor deposition. General QDSCs use polysulfide electrolyte because it is suitable for stabilizing QDs and its redox reaction is the best as compared with other redox systems. The improvement of redox reaction which is one of the slowest reactions in the kinetic analysis is closely connected with the enhancement of performance. For the enhancement on the overall performance of Si QDSC, the performance dependence on electrolyte composition was investigated. The concentrations of Na 2 S and S were varied for the activation of redox reaction and KCl concentration was optimized for the improvement of electrolyte characteristics. Consequently, the best performance of Si QDSC was obtained with 1 M Na 2 S, 2 M S, and 0.4 M KCl polysulfide electrolyte

Balancing surface adsorption and diffusion of lithium-polysulfides on nonconductive oxides for lithium?sulfur battery design

OpenAIRE

Tao, Xinyong; Wang, Jianguo; Liu, Chong; Wang, Haotian; Yao, Hongbin; Zheng, Guangyuan; Seh, Zhi Wei; Cai, Qiuxia; Li, Weiyang; Zhou, Guangmin; Zu, Chenxi; Cui, Yi

2016-01-01

Lithium?sulfur batteries have attracted attention due to their six-fold specific energy compared with conventional lithium-ion batteries. Dissolution of lithium polysulfides, volume expansion of sulfur and uncontrollable deposition of lithium sulfide are three of the main challenges for this technology. State-of-the-art sulfur cathodes based on metal-oxide nanostructures can suppress the shuttle-effect and enable controlled lithium sulfide deposition. However, a clear mechanistic understandin...

Understanding the role of lithium polysulfide solubility in limiting lithium-sulfur cell capacity

International Nuclear Information System (INIS)

Shen, Chao; Xie, Jianxin; Zhang, Mei; Andrei, Petru; Hendrickson, Mary; Plichta, Edward J.; Zheng, Jim P.

2017-01-01

Highlights: •At normal rate, LiPS soluble reaction pathway dominates the discharge process. •Reduction of sulfur to Li 2 S 8 is not inhibited by high Li 2 S 8 concentration. •Subsequent LiPS electrochemical reactions are restricted by LiPS solubility. •Specific energy of the Li-S cell was reevaluated considering LiPS solubility. -- Abstract: Although the cathode of lithium-sulfur (Li-S) batteries has a theoretical specific capacity of 1,672 mAh g −1 , its practical capacity is much smaller than this value and depends on the electrolyte/sulfur ratio. The operation of Li-S batteries under lean electrolyte conditions can be challenging, especially in the case when the solubility of lithium polysulfide (LiPS) sets an upper bound for polysulfide dissolution. In this work, specially designed cathode structures and electrolyte configurations were built in order to analyze the effects of LiPS solubility on cell capacity. Two reaction pathways involving the reduction of LiPS in liquid and solid phase are proposed and analyzed. We show that at discharge rates above 0.4 mA cm −2 the reaction in the liquid phase dominates the discharge process. Once the electrolyte becomes saturated, the solid phase LiPS cannot be further reduced and does not contribute to the capacity of the cells. This phenomenon prevents Li-S batteries from achieving their high theoretical specific capacity. Finally, the specific energy of the Li-S cell is reevaluated and discussed considering the limitation imposed by LiPS solubility.

Method for intercalating alkali metal ions into carbon electrodes

Science.gov (United States)

Doeff, Marca M.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard

1995-01-01

A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

A Nacre-Like Carbon Nanotube Sheet for High Performance Li-Polysulfide Batteries with High Sulfur Loading.

Science.gov (United States)

Pan, Zheng-Ze; Lv, Wei; He, Yan-Bing; Zhao, Yan; Zhou, Guangmin; Dong, Liubing; Niu, Shuzhang; Zhang, Chen; Lyu, Ruiyang; Wang, Cong; Shi, Huifa; Zhang, Wenjie; Kang, Feiyu; Nishihara, Hirotomo; Yang, Quan-Hong

2018-06-01

Lithium-sulfur (Li-S) batteries are considered as one of the most promising energy storage systems for next-generation electric vehicles because of their high-energy density. However, the poor cyclic stability, especially at a high sulfur loading, is the major obstacles retarding their practical use. Inspired by the nacre structure of an abalone, a similar configuration consisting of layered carbon nanotube (CNT) matrix and compactly embedded sulfur is designed as the cathode for Li-S batteries, which are realized by a well-designed unidirectional freeze-drying approach. The compact and lamellar configuration with closely contacted neighboring CNT layers and the strong interaction between the highly conductive network and polysulfides have realized a high sulfur loading with significantly restrained polysulfide shuttling, resulting in a superior cyclic stability and an excellent rate performance for the produced Li-S batteries. Typically, with a sulfur loading of 5 mg cm -2 , the assembled batteries demonstrate discharge capacities of 1236 mAh g -1 at 0.1 C, 498 mAh g -1 at 2 C and moreover, when the sulfur loading is further increased to 10 mg cm -2 coupling with a carbon-coated separator, a superhigh areal capacity of 11.0 mAh cm -2 is achieved.

Electrochemical properties of ether-based electrolytes for lithium/sulfur rechargeable batteries

International Nuclear Information System (INIS)

Barchasz, Céline; Leprêtre, Jean-Claude; Patoux, Sébastien; Alloin, Fannie

2013-01-01

Highlights: ► Liquid electrolyte composition for lithium/sulfur secondary batteries. ► Carbonate-based electrolytes prove not to be compatible with the sulfur electrode. ► Poor electrochemical performances related to low polysulfide solubility. ► Increase in the discharge capacity using ether solvents with high solvating ability such as PEGDME. ► Evidence of DIOX polymerization during cycling. -- Abstract: The lithium/sulfur (Li/S) battery is a promising electrochemical system that has a high theoretical capacity of 1675 mAh g −1 . However, the system suffers from several drawbacks: poor active material conductivity, active material dissolution, and use of the highly reactive lithium metal electrode. In this study, we investigated the electrolyte effects on electrochemical performances of the Li/S cell, by acting on the solvent composition. As conventional carbonate-based electrolytes turned out to be unusable in Li/S cells, alternative ether solvents had to be considered. Different kinds of solvent structures were investigated by changing the ether/alkyl moieties ratio to vary the lithium polysulfide solubility. This allowed to point out the importance of the solvent solvation ability on the discharge capacity. As the end of discharge is linked to the positive electrode passivation, an electrolyte having high solvation ability reduces the polysulfide precipitation and delays the positive electrode passivation

Atomic force microscopy studies on molybdenum disulfide flakes as sodium-ion anodes.

Science.gov (United States)

Lacey, Steven D; Wan, Jiayu; von Wald Cresce, Arthur; Russell, Selena M; Dai, Jiaqi; Bao, Wenzhong; Xu, Kang; Hu, Liangbing

2015-02-11

A microscale battery comprised of mechanically exfoliated molybdenum disulfide (MoS2) flakes with copper connections and a sodium metal reference was created and investigated as an intercalation model using in situ atomic force microscopy in a dry room environment. While an ethylene carbonate-based electrolyte with a low vapor pressure allowed topographical observations in an open cell configuration, the planar microbattery was used to conduct in situ measurements to understand the structural changes and the concomitant solid electrolyte interphase (SEI) formation at the nanoscale. Topographical observations demonstrated permanent wrinkling behavior of MoS2 electrodes upon sodiation at 0.4 V. SEI formation occurred quickly on both flake edges and planes at voltages before sodium intercalation. Force spectroscopy measurements provided quantitative data on the SEI thickness for MoS2 electrodes in sodium-ion batteries for the first time.

Preparation of Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) Material and its Application to Electrochemical Degradation of Methylene Blue in Sodium Chloride Solution

Science.gov (United States)

Riyanto; Prawidha, A. D.

2018-01-01

Electrochemical degradation of methylene blue using Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) electrode in sodium chloride have been done. The aim of this work was to degradation of methylene blue using Carbon-Chitosan-Polyvinyl Chloride (CC-PVC). Carbon chitosan composite electrode was preparing by Carbon and Chitosan powder and PVC in 4 mL tetrahydrofuran (THF) solvent and swirled flatly to homogeneous followed by drying in an oven at 100 °C for 3 h. The mixture was placed in stainless steel mould and pressed at 10 ton/cm2. Sodium chloride was used electrolyte solution. The effects of the current and electrolysis time were investigated using spectrophotometer UV-Visible. The experimental results showed that the carbon-chitosan composite electrode have higher effect in the electrochemical degradation of methylene blue in sodium chloride. Based on UV-visible spectra analysis shows current and electrolysis time has high effect to degradation of methylene blue in sodium chloride. Chitosan and polyvinyl chloride can strengthen the bond between the carbons so that the material has the high stability and conductivity. As conclusions is Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) electrode have a high electrochemical activity for degradation of methylene blue in sodium chloride.

In-test and post-test analyses of sodium-sulfur cells

Energy Technology Data Exchange (ETDEWEB)

Wada, Motoi; Kawamoto, Hiroyuki; Hatoh, Hisamitsu

1986-01-15

Cell life of sodium-sulfur cells is often determined by the degradation of the solid electrolyte. Solid electrolyte degradation will cause an increase of electrolyte resistivity, decrease of faradic efficiency, or even an electrolyte rupture which leads to a cell temperature rise due to direct reaction of reactants. Electrolyte degradation in actual sodium-sulfur cells is believed to be caused by the passage of sodium ion current across the solid electrolyte. The degree of degradation has been reported to be a function of amount of charge passed through the electrolyte, and the breakdown of the solid electrolyte was observed to occur above some threshold. For this reason, the concentration of sodium ion current density is to be avoided to prevent solid electrolyte from premature degradation and rupture, and the electrode structure for a sodium-sulfur cell should be determined with enough care to homogenize the current density distribution on the electrolyte. The longitudinal current density distribution of a sodium-sulfur cell was measured by attaching probing terminals on the electrode container. It was found that the current density distribution of a vertically supported cell was inhomogeneous due to the effect of gravity. This setup can be used as a way to locate the place where the first electrolyte cracking occurs. It was also found that the electrolyte cracking accompanies a fluctuation of cycling cell voltage that starts to appear several cycles before the noticeable break down of the electrolyte.

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility.

Science.gov (United States)

Yang, Chongyin; Suo, Liumin; Borodin, Oleg; Wang, Fei; Sun, Wei; Gao, Tao; Fan, Xiulin; Hou, Singyuk; Ma, Zhaohui; Amine, Khalil; Xu, Kang; Wang, Chunsheng

2017-06-13

Leveraging the most recent success in expanding the electrochemical stability window of aqueous electrolytes, in this work we create a unique Li-ion/sulfur chemistry of both high energy density and safety. We show that in the superconcentrated aqueous electrolyte, lithiation of sulfur experiences phase change from a high-order polysulfide to low-order polysulfides through solid-liquid two-phase reaction pathway, where the liquid polysulfide phase in the sulfide electrode is thermodynamically phase-separated from the superconcentrated aqueous electrolyte. The sulfur with solid-liquid two-phase exhibits a reversible capacity of 1,327 mAh/(g of S), along with fast reaction kinetics and negligible polysulfide dissolution. By coupling a sulfur anode with different Li-ion cathode materials, the aqueous Li-ion/sulfur full cell delivers record-high energy densities up to 200 Wh/(kg of total electrode mass) for >1,000 cycles at ∼100% coulombic efficiency. These performances already approach that of commercial lithium-ion batteries (LIBs) using a nonaqueous electrolyte, along with intrinsic safety not possessed by the latter. The excellent performance of this aqueous battery chemistry significantly promotes the practical possibility of aqueous LIBs in large-format applications.

All-MXene-Based Integrated Electrode Constructed by Ti3C2 Nanoribbon Framework Host and Nanosheet Interlayer for High-Energy-Density Li-S Batteries.

Science.gov (United States)

Dong, Yanfeng; Zheng, Shuanghao; Qin, Jieqiong; Zhao, Xuejun; Shi, Haodong; Wang, Xiaohui; Chen, Jian; Wu, Zhong-Shuai

2018-03-27

High-energy-density lithium-sulfur (Li-S) batteries hold promise for next-generation portable electronic devices, but are facing great challenges in rational construction of high-performance flexible electrodes and innovative cell configurations for actual applications. Here we demonstrated an all-MXene-based flexible and integrated sulfur cathode, enabled by three-dimensional alkalized Ti 3 C 2 MXene nanoribbon (a-Ti 3 C 2 MNR) frameworks as a S/polysulfides host (a-Ti 3 C 2 -S) and two-dimensional delaminated Ti 3 C 2 MXene (d-Ti 3 C 2 ) nanosheets as interlayer on a polypropylene (PP) separator, for high-energy and long-cycle Li-S batteries. Notably, an a-Ti 3 C 2 MNR framework with open interconnected macropores and an exposed surface area guarantees high S loading and fast ionic diffusion for prompt lithiation/delithiation kinetics, and the 2D d-Ti 3 C 2 MXene interlayer remarkably prevents the shuttle effect of lithium polysulfides via both chemical absorption and physical blocking. As a result, the integrated a-Ti 3 C 2 -S/d-Ti 3 C 2 /PP electrode was directly used for Li-S batteries, without the requirement of a metal current collector, and exhibited a high reversible capacity of 1062 mAh g -1 at 0.2 C and enhanced capacity of 632 mAh g -1 after 50 cycles at 0.5 C, outperforming the a-Ti 3 C 2 -S/PP electrode (547 mAh g -1 ) and conventional a-Ti 3 C 2 -S on an Al current collector (a-Ti 3 C 2 -S/Al) (597 mAh g -1 ). Furthermore, the all-MXene-based integrated cathode displayed outstanding rate capacity of 288 mAh g -1 at 10 C and long-life cyclability. Therefore, this proposed strategy of constructing an all-MXene-based cathode can be readily extended to assemble a large number of MXene-derived materials, from a group of 60+ MAX phases, for applications such as various batteries and supercapacitors.

Potassium Sodium Niobate-Based Lead-Free Piezoelectric Multilayer Ceramics Co-Fired with Nickel Electrodes

Directory of Open Access Journals (Sweden)

Shinichiro Kawada

2015-11-01

Full Text Available Although lead-free piezoelectric ceramics have been extensively studied, many problems must still be overcome before they are suitable for practical use. One of the main problems is fabricating a multilayer structure, and one solution attracting growing interest is the use of lead-free multilayer piezoelectric ceramics. The paper reviews work that has been done by the authors on lead-free alkali niobate-based multilayer piezoelectric ceramics co-fired with nickel inner electrodes. Nickel inner electrodes have many advantages, such as high electromigration resistance, high interfacial strength with ceramics, and greater cost effectiveness than silver palladium inner electrodes. However, widely used lead zirconate titanate-based ceramics cannot be co-fired with nickel inner electrodes, and silver palladium inner electrodes are usually used for lead zirconate titanate-based piezoelectric ceramics. A possible alternative is lead-free ceramics co-fired with nickel inner electrodes. We have thus been developing lead-free alkali niobate-based multilayer ceramics co-fired with nickel inner electrodes. The normalized electric-field-induced thickness strain (Smax/Emax of a representative alkali niobate-based multilayer ceramic structure with nickel inner electrodes was 360 pm/V, where Smax denotes the maximum strain and Emax denotes the maximum electric field. This value is about half that for the lead zirconate titanate-based ceramics that are widely used. However, a comparable value can be obtained by stacking more ceramic layers with smaller thicknesses. In the paper, the compositional design and process used to co-fire lead-free ceramics with nickel inner electrodes are introduced, and their piezoelectric properties and reliabilities are shown. Recent advances are introduced, and future development is discussed.

Energy Harvesting by Nickel Prussian Blue Analogue Electrode in Neutralization and Mixing Entropy Batteries.

Science.gov (United States)

Gomes, Wellington J A S; de Oliveira, Cainã; Huguenin, Fritz

2015-08-11

Some industries usually reduce the concentration of protons in acidic wastewater by conducting neutralization reactions and/or adding seawater to industrial effluents. This work proposes a novel electrochemical system that can harvest energy originating from entropic changes due to alteration in the concentration of sodium ions along wastewater treatment. Preparation of a self-assembled material from nickel Prussian blue analogue (NPBA) was the first step to obtain such electrochemical system. Investigation into the electrochemical properties of this material helped to evaluate its potential use in neutralization and mixing entropy batteries. Assessment of parameters such as the potentiodynamic profile of the current density as a function of the concentration of protons and sodium ions, charge capacity, and cyclability as well as the reversibility of the sodium ion electroinsertion process aided estimation of the energy storage efficiency of the system. Frequency-domain measurements and models and the proposed charge compensation mechanism provided the rate constants at different dc potentials. After each charge/discharge cycle, the NPBA electrode harvested 12.4 kJ per mol of intercalated sodium ion in aqueous solutions of NaCl at concentrations of 20 mM and 3.0 M. The full electrochemical cell consisted of an NPBA positive electrode and a negative electrode of silver particles dispersed in a polypyrrole electrode. This cell extracted 16.8 kJ per mol of intercalated ion after each charge/discharge cycle. On the basis of these results, the developed electrochemical system should encourage wastewater treatment and help to achieve sustainable growth.

The second sodium site in the dopamine transporter controls cation permeability and is regulated by chloride

DEFF Research Database (Denmark)

Borre, Lars; Andreassen, Thorvald F; Shi, Lei

2014-01-01

The dopamine transporter (DAT) belongs to the family of neurotransmitter:sodium symporters (NSSs) and controls dopamine (DA) homeostasis by mediating Na(+)- and Cl(-)-dependent reuptake of DA. Here we used two-electrode voltage clamp measurements in Xenopus oocytes together with targeted mutagene......The dopamine transporter (DAT) belongs to the family of neurotransmitter:sodium symporters (NSSs) and controls dopamine (DA) homeostasis by mediating Na(+)- and Cl(-)-dependent reuptake of DA. Here we used two-electrode voltage clamp measurements in Xenopus oocytes together with targeted...

Enhanced Cycling Stability of Lithium–Sulfur batteries by Electrostatic-Interaction

International Nuclear Information System (INIS)

Ma, Zhaoling; Huang, Xiaobing; Jiang, Qianqian; Huo, Jia; Wang, Shuangyin

2015-01-01

Highlights: • Electrostatic interaction is utilized to hinder the shuttling of polysulfides. • Directly functionalizing SG can better prolong the cycle life of Li–S batteries. • SG/PDDA showed significantly improved capacity retention. - Abstract: Lithiums–sulfur battery is considered as one of the most promising energy storage devices to replace the current Li ion batteries because of its high theoretical capacity of 1675 mA h g −1 . However, the poor cycle stability hinders the further development of this battery system. In order to improve the stability of Li–S batteries, the diffusion of polysulfides from electrodes into electrolyte should be suppressed. Herein, we utilize a positively charged polyelectrolyte to functionalize the electrode materials with the aim to hamper the polysulfides dissolution via electrostatic interaction between strong positively charged polyelectrolyte and negatively charged polysulfides anion. The effect of the functionalization quantity of poly(diallyl dimethylammonium) chloride (PDDA) and functionalization sequence on cycling performances is investigated in detail. It is found that the sulfur–graphene composite (SG) directly functionalized with 10 times PDDA exhibited best cycling stability. At a discharge current density of 0.2 C, much higher capacity retention was realized on the functionalized electrodes than the unfunctionalized (81% vs. 47.3%) after 120 cycles. The as-observed results demonstrate that the electrostatic interaction can effectively prolong the cycling life of Li–S batteries, which provides a new promising strategy for improving the electrochemical performance of Li–S batteries.

Facile preparation and enhanced capacitance of the polyaniline/sodium alginate nanofiber network for supercapacitors.

Science.gov (United States)

Li, Yingzhi; Zhao, Xin; Xu, Qian; Zhang, Qinghua; Chen, Dajun

2011-05-17

A porous and mat-like polyaniline/sodium alginate (PANI/SA) composite with excellent electrochemical properties was polymerized in an aqueous solution with sodium sulfate as a template. Ultraviolet-visible spectra, X-ray diffraction pattern, and Fourier transform infrared spectra were employed to characterize the PANI/SA composite, indicating that the PANI/SA composite was successfully prepared. The PANI/SA nanofibers with uniform diameters from 50 to 100 nm can be observed on scanning electron microscopy. Cyclic voltammetry and galvanostatic charge/discharge tests were carried out to investigate the electrochemical properties. The PANI/SA nanostructure electrode exhibits an excellent specific capacitance as high as 2093 F g(-1), long cycle life, and fast reflect of oxidation/reduction on high current changes. The remarkable electrochemical characteristic is attributed to the nanostructured electrode materials, which generates a high electrode/electrolyte contact area and short path lengths for electronic transport and electrolyte ion. The approach is simple and can be easily extended to fabricate nanostructural composites for supercapacitor electrode materials.

Functions of chalcogenide electrodes in solutions of complexing reagents and interfering ions

International Nuclear Information System (INIS)

Kiyanskij, V.V.

1990-01-01

The possibility to modify chalcogenide electrodes and their behaviour in solutions of complexing reagents for the development of new methods of potentiometric titration has been studied. It is shown that complexing reagents (EDTA, cupferron, 8-hydroxyquinoline, sodium dithiocarbaminate) and Cu(2), Hg(2) produce a strong effect on the functions of Ag, Cu, Cd, Pb - selective electrodes, which is used for titration of potential-determining and non-potential-determining ions ions (Sr 2+ , La 3+ etc.) and also for modification of sulfide-selecting electrode. A method of potentiometric titration of sulfates and chlorides with modified Cd- and Ag-selective electrodes is suggested

A Quasi-Solid-State Sodium-Ion Capacitor with High Energy Density.

Science.gov (United States)

Wang, Faxing; Wang, Xiaowei; Chang, Zheng; Wu, Xiongwei; Liu, Xiang; Fu, Lijun; Zhu, Yusong; Wu, Yuping; Huang, Wei

2015-11-18

A quasi-solid-state sodium-ion capacitor is demonstrated with nanoporous disordered carbon and macroporous graphene as the negative and positive electrodes, respectively, using a sodium-ion-conducting gel polymer electrolyte. It can operate at a cell voltage as high as 4.2 V with an energy density of record high 168 W h kg(-1). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dendrite-Free Sodium-Metal Anodes for High-Energy Sodium-Metal Batteries.

Science.gov (United States)

Sun, Bing; Li, Peng; Zhang, Jinqiang; Wang, Dan; Munroe, Paul; Wang, Chengyin; Notten, Peter H L; Wang, Guoxiu

2018-05-31

Sodium (Na) metal is one of the most promising electrode materials for next-generation low-cost rechargeable batteries. However, the challenges caused by dendrite growth on Na metal anodes restrict practical applications of rechargeable Na metal batteries. Herein, a nitrogen and sulfur co-doped carbon nanotube (NSCNT) paper is used as the interlayer to control Na nucleation behavior and suppress the Na dendrite growth. The N- and S-containing functional groups on the carbon nanotubes induce the NSCNTs to be highly "sodiophilic," which can guide the initial Na nucleation and direct Na to distribute uniformly on the NSCNT paper. As a result, the Na-metal-based anode (Na/NSCNT anode) exhibits a dendrite-free morphology during repeated Na plating and striping and excellent cycling stability. As a proof of concept, it is also demonstrated that the electrochemical performance of sodium-oxygen (Na-O 2 ) batteries using the Na/NSCNT anodes show significantly improved cycling performances compared with Na-O 2 batteries with bare Na metal anodes. This work opens a new avenue for the development of next-generation high-energy-density sodium-metal batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors.

Science.gov (United States)

Muralee Gopi, Chandu V V; Ravi, Seenu; Rao, S Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

2017-04-19

Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg -1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

Sodium setpoint and gradient in bicarbonate hemodialysis.

Science.gov (United States)

Basile, Carlo; Libutti, Pasquale; Lisi, Piero; Vernaglione, Luigi; Casucci, Francesco; Losurdo, Nicola; Teutonico, Annalisa; Lomonte, Carlo

2013-01-01

The demonstration of an individual osmolar setpoint in hemodialysis (HD) is crucial to individualize dialysate sodium concentrations. Furthermore, the diffusive gradient between plasma and dialysate sodium is important in the "fine tuning" of the intradialytic sodium mass balance (MB). The design of this study included part A: a retrospective analysis of predialysis plasma sodium concentrations extracted from a 6-year database in our HD population (147 prevalent white anuric patients); and part B: study of intradialytic sodium kinetics in 48 patients undergoing one 4-hour bicarbonate HD session. Direct potentiometry with an ion-selective electrode was used for sodium measurements. Study part A: the mean number of plasma sodium measurements per patient was 16.06 ± 14.03 over a mean follow-up of 3.55 ± 1.76 years. The mean of the averaged plasma sodium concentrations was 136.7 ± 2.1 mmol/L, with a low mean intraindividual coefficient of variation (1.39 ± 0.4). Study part B: mean predialysis and postdialysis plasma sodium concentrations were 135.8 ± 0.9 and 138.0 ± 0.9 mmol/L (p<0.001). Mean inlet dialyzer sodium concentration was 138.7 ± 1.1 mmol/L; the hourly diffusion concentration gradients showed a statistically significant transfer from dialysate to plasma (Wilks ? <0.0001). A statistically significant relationship was found between sodium MB and diffusion gradient (p<0.02), and between sodium MB and ultrafiltration volume (p<0.01). A relatively "fixed" and individual osmolar setpoint in HD patients was shown for the first time in a long-term follow-up. A dialysate sodium concentration of 140 mmol/L determined a dialysate to plasma sodium gradient.

H2S and polysulfide metabolism: Conventional and unconventional pathways.

Science.gov (United States)

Olson, Kenneth R

2018-03-01

It is now well established that hydrogen sulfide (H 2 S) is an effector of a wide variety of physiological processes. It is also clear that many of the effects of H 2 S are mediated through reactions with cysteine sulfur on regulatory proteins and most of these are not mediated directly by H 2 S but require prior oxidation of H 2 S and the formation of per- and polysulfides (H 2 S n , n = 2-8). Attendant with understanding the regulatory functions of H 2 S and H 2 S n is an appreciation of the mechanisms that control, i.e., both increase and decrease, their production and catabolism. Although a number of standard "conventional" pathways have been described and well characterized, novel "unconventional" pathways are continuously being identified. This review summarizes our current knowledge of both the conventional and unconventional. Copyright © 2017 Elsevier Inc. All rights reserved.

Investigation of the Li–S Battery Mechanism by Real-Time Monitoring of the Changes of Sulfur and Polysulfide Species during the Discharge and Charge

International Nuclear Information System (INIS)

Zheng, Dong; Liu, Dan; Harris, Joshua B.; Ding, Tianyao; Si, Jingyu

2016-01-01

The mechanism of the sulfur cathode in Li-S batteries has been proposed. It was revealed by the real-time quantitative determination of polysulfide species and elemental sulfur by means of the high performance liquid chromatography in the course of the discharge and recharge of a Li-S battery. A three-step reduction mechanism including two chemical equilibrium reactions was proposed for the sulfur cathode discharge. The typical two-plateau discharge curve for sulfur cathode can be explained. A two-step oxidation mechanism for the Li_2S and Li_2S_2 with a single chemical equilibrium among soluble polysulfide ions was proposed. In conclusion, the chemical equilibrium among S_5"2"-, S_6"2"-, S_7"2"- and S_8"2"- throughout the entire oxidation process resulted for the single flat recharge curve in Li-S batteries.

Development of an electrical connector for liquid sodium environment. Final Report

International Nuclear Information System (INIS)

Kataoka, Hajime; Noguchi, Koichi; Takatsudo, Hiroshi; Miyakawa, Shun-ichi

1998-07-01

The INstrumented irradiation Test Assembly (INTA) has been used to conduct precision on-line instrumented irradiation tests in the experimental fast reactor JOYO. In INTA, direct instrumentation wiring between the irradiation test section in the core and the upper structure section in the rotating plug makes INTA structurally complex and expensive. Instead of direct wiring, if an electrical connector capable of withstanding a heated liquid sodium environment could be used between the irradiation test section and the upper structure section, the upper mechanism of INTA could be reused and testing costs would be drastically reduced. Moreover, the reactor load factor would be improved because of reduced handling time for INTA. In an attempt to gain this advantage, research and development of an electric connector in a sodium environment was carried out from 1988 to 1996 at PNC. As no previous R and D had been conducted in this area, this development activity was conducted in a boot strap manner. The first test was carried out for a small model fabrication, the second was for a water partial model, and the third was for a sodium partial model. Based on those tests, a prototype design specification of the connector was determined. In the sodium partial model test, the resilience of the electrical connector insulation to the sodium environment was investigated. However, severe cracking in the ceramic insulator caused by the high temperature sodium environment was discovered at the junction of ceramic insulator and metallic electrode. Although additional sodium partial tests were performed for various material combinations of ceramic insulators, metallic electrodes, brazing materials and metallization materials, the results of the tests were unsatisfactory. Therefore, it was decided that the development of the connector in sodium should cease at PNC in 1997. (J.P.N.)

Electrolysis of acidic sodium chloride solution with a graphite anode. I. Graphite electrode

NARCIS (Netherlands)

Janssen, L.J.J.; Hoogland, J.G.

1969-01-01

A graphite anode evolving Cl from a chloride soln. is slowly oxidized to CO and CO2. This oxidn. causes a change in the characteristics of the electrode in aging, comprising a change of the nature of the graphite surface and an increase of the surface area. It appears that a new graphite electrode

A new inexpensive electrochemical meter for oxygen in sodium coolant

International Nuclear Information System (INIS)

Periaswami, G.; Rajan Babu, S.S.; Mathews, C.K.

1987-01-01

This report describes the development of an inexpensive oxygen meter for sodium coolant and gives the results of the test experiments. Calcia stabilized zirconia has been found to have necessary domain boundary characteristics at low temperatures for use as oxygen sensor in liquid sodium system. It is possible to obtain acceptable sensor cell resistance at temperatures as low as 230 C if K, K 2 O or Na, Na 2 O is used as reference electrode. The performance of these cells has been tested in bench top sodium loops over long periods. Their performance in terms of cell-out put variation with change in oxygen concentration in sodium has been found to be satisfactory. They also have sufficiently long life times since the kinetics of sodium attack on the electrolyte is slow at low temperatures. (author). 17 refs., 6 figs

High-performance graphene/sulphur electrodes for flexible Li-ion batteries using the low-temperature spraying method

Science.gov (United States)

Kumar, Pushpendra; Wu, Feng-Yu; Hu, Lung-Hao; Ali Abbas, Syed; Ming, Jun; Lin, Chia-Nan; Fang, Jason; Chu, Chih-Wei; Li, Lain-Jong

2015-04-01

Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (~70% capacity retention after 250 cycles), good coulombic efficiency (~98%) and high capacity (~1500 mA h g-1) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes.Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become

Direct extraction of a Na- beam from a sodium plasma

International Nuclear Information System (INIS)

Sasao, Namiko; Fujita, Junji; Yamaoka, Hitoshi; Wada, Motoi.

1990-07-01

Negative sodium ions (Na - ) were extracted from a small multi-cusp ion source. A steady state sodium plasma was produced by primary electrons in a sodium gas evaporating from a metal sample placed in the discharge chamber. The Na - current density of 1.5 μA/cm 2 was obtained from a single aperture of 1.5 mm diameter at relatively low discharge power of about 0.4 W and filament power of 50 W. Extraction characteristics were studied by changing the plasma electrode bias. The extracted Na - current showed dependence on the bias voltage similar to that of H - or Li - volume production. (author)

Development of analytical methods relating to aerosol and fission product release from hot and boiling sodium pools

International Nuclear Information System (INIS)

Mainka, E.

1978-11-01

Analytical methods are described for (a) sodium; (b) the following anions of sodium aerosols: OH - , CO 2 - and HCO 3 - ; (c) fission products Cs and Sr. For sodium, the ion selective electrode was used. The anions were determined by a titration method using phenolphthalein and methyl orange as indicators. Atomic absorption spectroscopy was used for Cs and Sr. (U.K.)

The role of oxygen in porous molybdenum electrodes for the alkali metal thermoelectric converter

International Nuclear Information System (INIS)

Williams, R.M.; Nagasubramanian, G.; Khanna, S.K.; Bankston, C.P.; Thakoor, A.P.; Cole, T.

1986-01-01

The alkali metal thermoelectric converter is a direct energy conversion device, utilizing a high alkali metal activity gradient to generate electrical power. Its operation is based on the unique ion conductive properties of beta''-alumina solid electrolyte. The major barrier to application of this device is identification of an electrode which can maintain optimum power densities for operation times of >10,000h. Thin, porous molybdenum electrodes have shown the best performance characteristics, but show a variety of time dependent phenomena, including eventual degradation to power densities 3-5 times lower than initial values. Several Na-Mo-O compounds, including Na/sub 2/MoO/sub 4/ and Na/sub 2/Mo/sub 3/O/sub 6/, are formed during AMTEC operation. These compounds may be responsible for enhanced Na transport through Mo electrodes via sodium ion conduction, and eventual performance degradation due to their volatilization and decomposition. No decomposition of beta''-alumina has been observed under simulated AMTEC operating conditions up to 1373 K. In this paper, we present a model for chemical reactions occurring in porous molybdenum electrodes. The model is based on thermochemical and kinetic data, known sodium-molybdenum-oxygen chemistry, x-ray diffraction analysis of molybdenum and molybdenum oxide electrodes, and the electrochemical behavior of the cell

High capacity electrode materials for batteries and process for their manufacture

Science.gov (United States)

Johnson, Christopher S.; Xiong, Hui; Rajh, Tijana; Shevchenko, Elena; Tepavcevic, Sanja

2018-04-03

The present invention provides a nanostructured metal oxide material for use as a component of an electrode in a lithium-ion or sodium-ion battery. The material comprises a nanostructured titanium oxide or vanadium oxide film on a metal foil substrate, produced by depositing or forming a nanostructured titanium dioxide or vanadium oxide material on the substrate, and then charging and discharging the material in an electrochemical cell from a high voltage in the range of about 2.8 to 3.8 V, to a low voltage in the range of about 0.8 to 1.4 V over a period of about 1/30 of an hour or less. Lithium-ion and sodium-ion electrochemical cells comprising electrodes formed from the nanostructured metal oxide materials, as well as batteries formed from the cells, also are provided.

Electrochemical Performance of Electrospun carbon nanofibers as free-standing and binder-free anodes for Sodium-Ion and Lithium-Ion Batteries

International Nuclear Information System (INIS)

Jin, Juan; Shi, Zhi-qiang; Wang, Cheng-yang

2014-01-01

Highlights: • Electrospun carbon nanofiber webs were prepared by pyrolysis of polyacrylonitrile. • The webs as binder-free and current collector-free electrodes for SIBs and LIBs. • Different layer spacing and pore size for Li and Na lead different electrochemical behavior. • Electrochemical performances of the electrodes were high. - Abstract: A series of hard carbon nanofiber-based electrodes derived from electrospun polyacrylonitrile (PAN) nanofibers (PAN-CNFs) have been fabricated by stabilization in air at about 280 °C and then carbonization in N 2 at heat treatment temperatures (HTT) between 800 and 1500 °C. The electrochemical performances of the binder-free, current collector-free carbon nanofiber-based anodes in lithium-ion batteries and sodium-ion batteries are systematically investigated and compared. We demonstrate the presence of similar alkali metal insertion mechanisms in both cases, but just the differences of the layer spacing and pore size available for lithium and sodium ion lead the discharge capacity delivered at sloping region and plateau region to vary from the kinds of alkali elements. Although the anodes in sodium-ion batteries show poorer rate capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 275 mAh g −1 and similar cycling stability due to the conductive 3-D network, weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets. The feature of high capacity and stable cycling performance makes PAN-CNFs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries

Pseudocapacitive Sodium Storage in Mesoporous Single-Crystal-like TiO2-Graphene Nanocomposite Enables High-Performance Sodium-Ion Capacitors.

Science.gov (United States)

Le, Zaiyuan; Liu, Fang; Nie, Ping; Li, Xinru; Liu, Xiaoyan; Bian, Zhenfeng; Chen, Gen; Wu, Hao Bin; Lu, Yunfeng

2017-03-28

Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO 2 mesocages anchored on graphene as a sodium storage material. The architecture of the nanocomposite results in pseudocapacitive charge storage behavior with fast kinetics, high reversibility, and negligible degradation to the micro/nanostructure. The nanocomposite delivers a high capacity of 268 mAh g -1 at 0.2 C, which remains 126 mAh g -1 at 10 C for over 18 000 cycles. Coupling with a carbon-based cathode, a full cell of sodium-ion capacitor successfully demonstrates a high energy density of 64.2 Wh kg -1 at 56.3 W kg -1 and 25.8 Wh kg -1 at 1357 W kg -1 , as well as an ultralong lifespan of 10 000 cycles with over 90% of capacity retention.

Pulsed voltage deposited lead selenide thin film as efficient counter electrode for quantum-dot-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Jin, Bin Bin [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Department of Chemical Engineering, Institute of Chemical Industry, Shaanxi Institute of Technology, Xi’an 710300 (China); Wang, Ye Feng [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Wang, Xue Qing [Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024 (China); Zeng, Jing Hui, E-mail: jhzeng@ustc.edu [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China)

2016-04-30

Highlights: • PbSe thin film is deposited on FTO glass by a pulse voltage electrodeposition method. • The thin film is used as counter electrode (CE) in quantum dot-sensitized solar cell. • Superior electrocatalytic activity and stability in the polysulfide electrolyte is received. • The narrow band gap characteristics and p-type conductivity enhances the cell efficiency. • An efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells. - Abstract: Lead selenide (PbSe) thin films were deposited on fluorine doped tin oxide (FTO) glass by a facile one-step pulse voltage electrodeposition method, and used as counter electrode (CE) in CdS/CdSe quantum dot-sensitized solar cells (QDSSCs). A power conversion efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells, which is much better than that of 2.39% received using Pt CEs. The enhanced performance is attributed to the extended absorption in the near infrared region, superior electrocatalytic activity and p-type conductivity with a reflection of the incident light at the back electrode in addition. The physical and chemical properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), reflectance spectra, electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The present work provides a facile pathway to an efficient CE in the QDSSCs.

Novel tandem structure employing mesh-structured Cu2S counter electrode for enhanced performance of quantum dot-sensitized solar cells

International Nuclear Information System (INIS)

Yang, Yue-Yong; Zhang, Quan-Xin; Wang, Tian-Zi; Zhu, Li-Feng; Huang, Xiao-Ming; Zhang, Yi-Duo; Hu, Xing; Li, Dong-Mei; Luo, Yan-Hong; Meng, Qing-Bo

2013-01-01

Highlights: ► This is the first report on practical tandem structures for quantum dot-sensitized solar cells (QDSCs). ► Mesh-structured Cu 2 S counter electrode exhibits high catalytic activity and good transmittance. ► Influence of photoanode thickness on tandem QDSCs has been systematically studied. ► Tandem QDSCs shows higher photocurrent and efficiency as against the single-photoanode cell. ► This structure can achieve higher efficiency with different QD sensitizers for complementary spectral responses. -- Abstract: A practical tandem structure with a semitransparent mesh-structured Cu 2 S counter electrode sandwiched between two TiO 2 photoelectrodes has been designed for quantum dot-sensitized solar cells (QDSCs). The mesh-structured Cu 2 S counter electrode exhibits high catalytic activity for polysulfide electrolyte. CdS/CdSe quantum dot-sensitized TiO 2 films have been applied as both top and bottom photoelectrodes to testify the effectiveness of the tandem structure. The influence of the TiO 2 film thickness on the performance of the tandem cell has been systematically studied. The optimized tandem QDSC shows an improved photocurrent and 12-percent increase of efficiency over the top cell with a 4.7 μm thick top cell and an 11.0 μm thick bottom cell, presenting a new effective approach towards highly efficient QDSCs

Lithium and sodium batteries with polysulfide electrolyte

KAUST Repository

Li, Mengliu; Ming, Jun; Li, Lain-Jong

2017-01-01

A battery comprising: at least one cathode, at least one anode, at least one battery separator, and at least one electrolyte disposed in the separator, wherein the anode is a lithium metal or lithium alloy anode or an anode adapted for intercalation

Preparation and electrochemical property of TiO_2/Nano-graphite composite anode for electro-catalytic degradation of ceftriaxone sodium

International Nuclear Information System (INIS)

Guo, Xiaolei; Li, Dong; Wan, Jiafeng; Yu, Xiujuan

2015-01-01

Titanium dioxide/Nano-graphite (TiO_2/Nano-G) composite was synthesized by a sol-gel method and TiO_2/Nano-G electrode was prepared in hot-press approach. The composite was characterized by X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR), scanning electrons microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical performance of the TiO_2/Nano-G anode electrode was investigated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electro-catalytic performance was evaluated by the yield of ·OH radicals, degradation of methyl orange and ceftriaxone sodium. The results demonstrated that TiO_2 nanoparticles were dispersed on the surface and interlamination of the Nano-G uniformly, TiO_2/Nano-G electrode owned higher electro-catalytic oxidation activity and stability than Nano-G electrode. Degradation rate of ceftriaxone sodium within 120 min by TiO_2(40)/Nano-G electrode was 97.7%. And ·OH radicals given by TiO_2/Nano-G electrode was higher than that of Nano-G electrode and DSA (Ti/IrO_2-RuO_2) electrode. The excellent electro-catalytic performance could be ascribed to the admirable conductive property of the Nano-G and more production of ·OH offered by TiO_2(40)/Nano-G electrode.

Na-ion capacitor using sodium pre-doped hard carbon and activated carbon

International Nuclear Information System (INIS)

Kuratani, Kentaro; Yao, Masaru; Senoh, Hiroshi; Takeichi, Nobuhiko; Sakai, Tetsuo; Kiyobayashi, Tetsu

2012-01-01

We assembled a sodium-ion capacitor (Na-IC) by combining sodium pre-doped hard carbon (HC) as the negative- and activated carbon (AC) as the positive-electrode. The electrochemical properties were compared with two lithium-ion capacitors (Li-ICs) in which the negative electrodes were prepared with Li pre-doped HC and mesocarbon microbeads (MCMB). The positive and negative electrodes were prepared using the established doctor blade method. The negative electrodes were galvanostatically pre-doped with Na or Li to 80% of the full capacity of carbons. The potential of the negative electrodes after pre-doping was around 0.0 V vs. Na/Na + or Li/Li + , which resulted in the higher output potential difference of the Na-IC and Li-ICs than that of the conventional electrochemical double-layer capacitors (EDLCs) because AC positive electrode works in the same principle both in the ion capacitors and in the EDLC. The state-of-charge of the negative electrode varied 80 ± 10% during the electrochemical charging and discharging. The capacity of the cell was evaluated using galvanostatic charge–discharge measurement. At the discharge current density of 10 mA cm −2 , the Na-IC maintained 70% of the capacity that obtained at the current density of 0.5 mA cm −2 , which was comparable to the Li-ICs. At 50 mA cm −2 , the capacities of the Li-IC(MCMB) and the Na-IC dropped to 20% whereas the Li-IC(HC) retained 30% of the capacity observed at 0.5 mA cm −2 . The capacities of the Na-IC and Li-ICs decreased by 9% and 3%, respectively, after 1000 cycles of charging and discharging.

Determination of uranyl ion by potentiometric titration using an uranyl-selective electrode

International Nuclear Information System (INIS)

Nassory, N.S.

1990-01-01

A potentiometric titration of uranyl ion is described using an uranyl selective electrode based on a membrane containing a complex of UO 2 -bis[di-4-(1,1,3,3-tetramethylbutyl)phenyl phosphate] as an ion-exchanger and tritolyl phosphate as a solvent mediator. The titrations were carried out with various titrants: Sodium hydroxide, potassium fluoride and sodium salts of acetate, oxalate and citrate. The equivalence points were determined by Gran's method. Good results were obtained by using sodium oxalate as a titrant for the determination of uranium in several samples of ammonium diuranate. The results were quite comparable with those obtained by X-ray fluorescence spectrometry. (orig.)

Synthesis and characterizaton of inorganic materials for sodium-ion batteries

Science.gov (United States)

Shanmugam, Rengarajan

Development of low-cost energy storage devices is critical for wide-scale implementation of intermittent renewable energy technologies and improving the electricity grid. Commercial devices remain prohibitively expensive or lack the performance specifications for a wider market reach. Na-ion batteries would perfectly suited for these large-scale applications as the raw materials (such as soda ash, salt, etc.) are plentiful, inexpensive and geographically unconstrained. However, extensive materials research on insertion electrodes is required for better understanding of the electrochemical and structural properties and engineering high performance Na-ion batteries. This thesis research involves exploratory study on new insertion materials with various crystallographic structure-types and extensive characterization of promising new inorganic compositions. Tunnel-type materials, sodium nickel phosphate-Na4Ni7(PO4)6, and sodium cobalt titanate- Na0.8Co0.4Ti1.6O4, were investigated to capitalize on the intrinsic structural stability offered by framework materials. Sol-gel and solid-state reaction synthetic techniques were employed for inorganic powder synthesis. Galvanostatic and potentiostatic testing confirm reversible sodium insertion/de-insertion reactions albeit with inadequate electrochemical characteristics (high voltage hysteresis> 1V). Subsequent efforts involved investigating layer-structured materials supporting fast ionic transport for better electrochemical performance. P2-sodium nickel titanate, Na2/3[Ni1/3Ti2/3]O2 (P2NT), with prismatic sodium co-ordination, was synthesized by solid-state technique. The 'bifunctional' oxide contains Ni2+/4+ and Ti4+/3+ redox couples with redox potentials of 3.6 V, 0.7 V vs. Na/Na+, respectively. This bifunctional approach would simplify electrode processing and provide cost reduction opportunities in battery manufacturing. The structural changes monitored using ex-situ XRD demonstrate a favorably broad solid

Photoelectrocatalytic Degradation of Sodium Oxalate by TiO2/Ti Thin Film Electrode

Directory of Open Access Journals (Sweden)

Chen-Yu Chang

2012-01-01

Full Text Available The photocatalytically active TiO2 thin film was deposited on the titanium substrate plate by chemical vapor deposition (CVD method, and the photoelectrocatalytic degradation of sodium oxalate was investigated by TiO2 thin film reactor prepared in this study with additional electric potential at 365 nm irradiation. The batch system was chosen in this experiment, and the controlled parameters were pH, different supporting electrolytes, applied additional potential, and different electrolyte solutions that were examined and discussed. The experimental results revealed that the additional applied potential in photocatalytic reaction could prohibit recombination of electron/hole pairs, but the photoelectrocatalytic effect was decreased when the applied electric potential was over 0.25 V. Among the electrolyte solutions added, sodium sulfate improved the photoelectrocatalytic effect most significantly. At last, the better photoelectrocatalytic degradation of sodium oxalate occurred at pH 3 when comparing the pH influence.

A new method synthesis polyaniline/multi-walled carbon nanotube composites for supercapacitor electrodes

Energy Technology Data Exchange (ETDEWEB)

Pan, J.; Wei, X.; Zhou, S.P. [Shandong Univ. of Technology, Zibo (China). School of Chemical Engineering

2010-07-01

A series of polyaniline multi-walled nanotube (PANIMWNT) composite films were prepared using an in situ polymerization technique. Scanning electron microscopy (SEM) was used to characterize the morphology and microstructure of the samples. Cyclic voltammetry (CV), impedance spectroscopy, and galvanostatic charge/discharge analyses were used to determine the electrochemical properties of the PANIMWNT films in a 3-electrode system. The electrochemical performance of PANI, PANIMWNT, and MWNT film performances was then compared. Results of the study showed that the PANI electrodes showed a much higher capacitance than the MWNT and PANIMWNT electrodes. Both the PANI and PANIMWNT nanocomposites showed good electrochemical capacitance. The improved performance of the electrodes was attributed to the presence of sodium hypochlorite (NaClO). 5 refs.

Testing and performance of electrolytic oxygen meters for use in liquid sodium

International Nuclear Information System (INIS)

Taylor, R.G.; Thompson, R.

1983-01-01

The performance of yttria-doped thoria ceramic electrochemical oxygen meters in liquid sodium is described. Tests were carried out using laboratory loops. Temperature coefficients of the oxygen meters have been measured between 380 0 C and 480 0 C, and the response to changes in oxygen level using cold-trap temperatures from 125 0 C to 250 0 C was determined. The ceramic has been shown to give good performance over lifetimes exceeding 400 days in some cases. The temperature coefficients and response to oxygen level changes are in good agreement with thermodynamic predictions. The effect of running the meters in high-oxygen sodium has been studied and a general mode of failure has been shown to be grain-boundary attack by oxygen/sodium solutions. The effect of #betta#-radiation on the meters has been studied. The meters with a metal/metal oxide reference electrode were unaffected by dose rates up to 52860 mGy h - 1 . Meters with an air reference electrode do show an effect as a voltage reduction at levels down to 2420 mGy h - 1 . This effect was temperature-dependent and was insignificant at 500 0 C. (orig.)

Why does the lumen maintenance of sodium-scandium metal halide lamps improve by VHF operation?

International Nuclear Information System (INIS)

Van Erk, W; Luijks, G M J F; Hitchcock, W

2011-01-01

Lifetime experiments show that sodium-scandium metal halide lamps perform better on very high frequency (VHF) drivers than on low frequency (LF) constant wattage autotransformer (CWA) ballasts. The question why, will be addressed with focus on arc tube aspects. It is argued that at high frequency operation sodium loss is less, and that the absence of thermal fluctuations in the electrode tip causes less damage and cracking to this part of the electrode. Sudden lm W -1 drops, observed with CWA-operated lamps, most probably occur when the arc attaches on such a corroded and cracked surface. Thorium is effective as an emitter both in the CWA and the VHF operation mode, despite the absence of cataphoretic transport to the cathode in the VHF case.

Why does the lumen maintenance of sodium-scandium metal halide lamps improve by VHF operation?

Energy Technology Data Exchange (ETDEWEB)

Van Erk, W [Philips Lighting, Sondervick 47, 5505 NB Veldhoven (Netherlands); Luijks, G M J F [Advanced Development Lighting, Philips Lighting, PO Box 80020, 5600 JM Eindhoven (Netherlands); Hitchcock, W, E-mail: Gerard.luijks@philips.com [Philips Lighting Company, 7265 Route 54, Bath, NY 14810 (United States)

2011-06-08

Lifetime experiments show that sodium-scandium metal halide lamps perform better on very high frequency (VHF) drivers than on low frequency (LF) constant wattage autotransformer (CWA) ballasts. The question why, will be addressed with focus on arc tube aspects. It is argued that at high frequency operation sodium loss is less, and that the absence of thermal fluctuations in the electrode tip causes less damage and cracking to this part of the electrode. Sudden lm W{sup -1} drops, observed with CWA-operated lamps, most probably occur when the arc attaches on such a corroded and cracked surface. Thorium is effective as an emitter both in the CWA and the VHF operation mode, despite the absence of cataphoretic transport to the cathode in the VHF case.

Monitoring and measurement of oxygen concentrations in liquid sodium

International Nuclear Information System (INIS)

Smith, D.L.

1976-01-01

The measurement of oxygen concentrations in sodium at levels of interest for LMFBR applications is reviewed. Additional data are presented to support the validity of the vanadium-equilibration method as a reference for determination of oxygen concentrations in sodium at levels equal to or less than 15 ppM. Operating experience with electrochemical oxygen meters that have a thoria-yttria electrolyte and a Na--Na 2 O reference electrode is described. Meter lifetimes in excess of one year have generally been achieved for operating temperatures of 352 and 402 0 C, and fairly stable emfs have been observed for periods of several months. 7 fig, 21 references

Free-standing Hierarchical Porous Assemblies of Commercial TiO_2 Nanocrystals and Multi-walled Carbon Nanotubes as High-performance Anode Materials for Sodium Ion Batteries

International Nuclear Information System (INIS)

Liu, Xiong; Xu, Guobao; Xiao, Huaping; Wei, Xiaolin; Yang, Liwen

2017-01-01

Highlights: • Utilization of commercial nanomaterials to freestanding sodium electrode is demonstrated. • Free-standing electrodes composed of TiO_2 and MWCNTs are hierarchically porous. • Hierarchical porous architecture benefits charge transport and interfacial Na"+ adsorption. • Free-standing hierarchical porous electrodes exhibit superior Na storage performance. - Abstract: Freestanding hierarchical porous assemblies of commercial TiO_2 nanocrystals and multi-wall carbon nanotubes (MWCNTs) as electrode materials for sodium ion batteries (SIBs) are prepared via modified vacuum filtration, free-drying and annealing. Microstructure characterizations reveal that TiO_2 nanocrystals are confined in hierarchically porous, highly electrically conductive and mechanically robust MWCNTs networks with cross-linking of thermally-treated bovine serum albumin. The hierarchical porous architecture not only enables rapid charge transportation and sufficient interaction between electrode and electrolyte, but also guarantees abundant interfacial sites for Na"+ adsorption, which benefits substantial contribution from pseudocapacitive Na storage. When it is used directly as an anode for sodium-ion batteries, the prepared electrode delivers high specific capacity of 100 mA h g"−"1 at a current density of 3000 mA g"−"1, and 150 mA h g"−"1 after 500 cycles at a current density of 500 mA g"−"1. The low-cost TiO_2-based freestanding anode has large potential application in high-performance SIBs for portable, flexible and wearable electronics.

Fluoride Removal From Drinking Water by Electrocoagulation Using Iron and Aluminum Electrodes

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Takdastan

2014-07-01

Full Text Available Background Existence of fluoride in drinking water above the permissible level causes human skeletal fluorosis. Objectives Electrocoagulation by iron and aluminum electrodes was proposed for removing fluoride from drinking water. Materials and Methods Effects of different operating conditions such as treatment time, initial pH, applied voltage, type and number of electrodes, the spaces between aluminum and iron electrodes, and energy consumption during electrocoagulation were investigated in the batch reactor. Variable concentrations of fluoride solution were prepared by mixing proper amounts of sodium fluoride with deionized water. Results Experimental results showed that aluminum electrode is more effective in fluoride removal than iron, as in 40 minutes and initial pH of 7.5 at 20 V, the fluoride removal process reached to 97.86%. The final recommendable limit of fluoride (1.5 mg/L was obtained in 10 minutes at 20 V with the aluminum electrode. Conclusions In electrocoagulation with iron and aluminum electrodes, increase of voltage, number of electrodes and reaction time as well as decrease of the spaces between electrodes, enhanced the fluoride removal efficiency from drinking water. In addition the effect of pH and initial concentration of fluoride varied with types of electrodes.

Nanocomposite Materials for the Sodium-Ion Battery: A Review.

Science.gov (United States)

Liang, Yaru; Lai, Wei-Hong; Miao, Zongcheng; Chou, Shu-Lei

2018-02-01

Clean energy has become an important topic in recent decades because of the serious global issues related to the development of energy, such as environmental contamination, and the intermittence of the traditional energy sources. Creating new battery-related energy storage facilities is an urgent subject for human beings to address and for solutions for the future. Compared with lithium-based batteries, sodium-ion batteries have become the new focal point in the competition for clean energy solutions and have more potential for commercialization due to the huge natural abundance of sodium. Nevertheless, sodium-ion batteries still exhibit some challenges, like inferior electrochemical performance caused by the bigger ionic size of Na + ions, the detrimental volume expansion, and the low conductivity of the active materials. To solve these issues, nanocomposites have recently been applied as a new class of electrodes to enhance the electrochemical performance in sodium batteries based on advantages that include the size effect, high stability, and excellent conductivity. In this Review, the recent development of nanocomposite materials applied in sodium-ion batteries is summarized, and the existing challenges and the potential solutions are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improving the Performance of Lithium–Sulfur Batteries by Conductive Polymer Coating

KAUST Repository

Yang, Yuan

2011-11-22

Rechargeable lithium-sulfur (Li-S) batteries hold great potential for next-generation high-performance energy storage systems because of their high theoretical specific energy, low materials cost, and environmental safety. One of the major obstacles for its commercialization is the rapid capacity fading due to polysulfide dissolution and uncontrolled redeposition. Various porous carbon structures have been used to improve the performance of Li-S batteries, as polysulfides could be trapped inside the carbon matrix. However, polysulfides still diffuse out for a prolonged time if there is no effective capping layer surrounding the carbon/sulfur particles. Here we explore the application of conducting polymer to minimize the diffusion of polysulfides out of the mesoporous carbon matrix by coating poly(3,4-ethylenedioxythiophene)- poly(styrene sulfonate) (PEDOT:PSS) onto mesoporous carbon/sulfur particles. After surface coating, coulomb efficiency of the sulfur electrode was improved from 93% to 97%, and capacity decay was reduced from 40%/100 cycles to 15%/100 cycles. Moreover, the discharge capacity with the polymer coating was ∼10% higher than the bare counterpart, with an initial discharge capacity of 1140 mAh/g and a stable discharge capacity of >600 mAh/g after 150 cycles at C/5 rate. We believe that this conductive polymer coating method represents an exciting direction for enhancing the device performance of Li-S batteries and can be applicable to other electrode materials in lithium ion batteries. © 2011 American Chemical Society.

Spatiotemporal electrochemical measurements across an electric double layer capacitor electrode with application to aqueous sodium hybrid batteries

Science.gov (United States)

Tully, Katherine C.; Whitacre, Jay F.; Litster, Shawn

2014-02-01

This paper presents in-situ spatiotemporal measurements of the electrolyte phase potential within an electric double layer capacitor (EDLC) negative electrode as envisaged for use in an aqueous hybrid battery for grid-scale energy storage. The ultra-thick electrodes used in these batteries to reduce non-functional material costs require sufficiently fast through-plane mass and charge transport to attain suitable charging and discharging rates. To better evaluate the through-plane transport, we have developed an electrode scaffold (ES) for making in situ electrolyte potential distribution measurements at discrete known distances across the thickness of an uninterrupted EDLC negative electrode. Using finite difference methods, we calculate local current, volumetric charging current and charge storage distributions from the spatiotemporal electrolyte potential measurements. These potential distributions provide insight into complex phenomena that cannot be directly observed using other existing methods. Herein, we use the distributions to identify areas of the electrode that are underutilized, assess the effects of various parameters on the cumulative charge storage distribution, and evaluate an effectiveness factor for charge storage in EDLC electrodes.

Improved performance of CdS/CdSe quantum dot-sensitized solar cells using Mn-doped PbS quantum dots as a catalyst in the counter electrode

International Nuclear Information System (INIS)

Kim, Byung-Man; Son, Min-Kyu; Kim, Soo-Kyoung; Hong, Na-Yeong; Park, Songyi; Jeong, Myeong-Soo; Seo, Hyunwoong; Prabakar, Kandasamy; Kim, Hee-Je

2014-01-01

Highlights: • PbS QDs synthesized using the SILAR method act not only as the electrochemical catalysts but as donors providing additional electrons under illumination. • The electrochemical and optical properties of the PbS QDs were enhanced considerably after Mn 2+ doping. • The electron supply from the counter electrode was significantly activated by Mn 2+ doping, improving the performance of QDSSC. - Abstract: This study reports the enhanced catalytic ability of Mn-doped PbS QDs synthesized using a successive ionic layer adsorption and reaction (SILAR) method for quantum dot-sensitized solar cells (QDSSCs). Electrochemical and optical analysis of each material showed that the catalytic ability of the PbS electrode was improved significantly by Mn 2+ doping. Two factors can explain this behavior. The first is that intentional impurities have an impact on the structure of the host material, such as increases in surface roughness. The other is that dopants create new energy states that delay the exciton recombination time and allow charge separation to be activated. As a result, the photoelectron supply from the counter electrode is accelerated, resulting in vigorous redox reactions at the polysulfide electrolyte. The performance of the CdS/CdSe QDSSC using a Mn-doped PbS counter electrode was compared with those using the Pt and PbS counter electrodes. Finally, a power conversion efficiency of 3.61% was achieved with the Mn-doped PbS counter electrode (V OC = 0.61 V, J SC = 11.67 mA cm −2 , FF = 0.51) under one sun illumination (100 mW cm −2 ), which is ∼40% higher than that of CdS/CdSe QDSSCs with the bare PbS counter electrode

High-performance graphene/sulphur electrodes for flexible Li-ion batteries using the low-temperature spraying method

KAUST Repository

Kumar, Pushpendra

2015-01-01

Elementary sulphur (S) has been shown to be an excellent cathode material in energy storage devices such as Li-S batteries owing to its very high capacity. The major challenges associated with the sulphur cathodes are structural degradation, poor cycling performance and instability of the solid-electrolyte interphase caused by the dissolution of polysulfides during cycling. Tremendous efforts made by others have demonstrated that encapsulation of S materials improves their cycling performance. To make this approach practical for large scale applications, the use of low-cost technology and materials has become a crucial and new focus of S-based Li-ion batteries. Herein, we propose to use a low temperature spraying process to fabricate graphene/S electrode material, where the ink is composed of graphene flakes and the micron-sized S particles prepared by grinding of low-cost S powders. The S particles are found to be well hosted by highly conductive graphene flakes and consequently superior cyclability (∼70% capacity retention after 250 cycles), good coulombic efficiency (∼98%) and high capacity (∼1500 mA h g-1) are obtained. The proposed approach does not require high temperature annealing or baking; hence, another great advantage is to make flexible Li-ion batteries. We have also demonstrated two types of flexible batteries using sprayed graphene/S electrodes. © The Royal Society of Chemistry 2015.

Glassy carbon electrode modified with multi-walled carbon nanotubes sensor for the quantification of antihistamine drug pheniramine in solubilized systems

Directory of Open Access Journals (Sweden)

Rajeev Jain

2012-02-01

Full Text Available A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate. The experimental results suggest that the pheniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response. Peak current response is linearly dependent on the concentration of pheniramine in the range 200–1500 μg/mL with correlation coefficient 0.9987. The limit of detection is 58.31 μg/mL. The modified electrode shows good sensitivity and repeatability. Keywords: Pheniramine, Sodium lauryl sulfate (SLS, Glassy carbon electrode modified with multi-walled carbon nanotubes (GCE-MWCNTs, Solubilized systems, Voltammetric quantification

High-performance sodium-organic battery by realizing four-sodium storage in disodium rhodizonate

Science.gov (United States)

Lee, Minah; Hong, Jihyun; Lopez, Jeffrey; Sun, Yongming; Feng, Dawei; Lim, Kipil; Chueh, William C.; Toney, Michael F.; Cui, Yi; Bao, Zhenan

2017-11-01

Sodium-ion batteries (SIBs) for grid-scale applications need active materials that combine a high energy density with sustainability. Given the high theoretical specific capacity 501 mAh g-1, and Earth abundance of disodium rhodizonate (Na2C6O6), it is one of the most promising cathodes for SIBs. However, substantially lower reversible capacities have been obtained compared with the theoretical value and the understanding of this discrepancy has been limited. Here, we reveal that irreversible phase transformation of Na2C6O6 during cycling is the origin of the deteriorating redox activity of Na2C6O6. The active-particle size and electrolyte conditions were identified as key factors to decrease the activation barrier of the phase transformation during desodiation. On the basis of this understanding, we achieved four-sodium storage in a Na2C6O6 electrode with a reversible capacity of 484 mAh g-1, an energy density of 726 Wh kg-1cathode, an energy efficiency above 87% and a good cycle retention.

Decorating Waste Cloth via Industrial Wastewater for Tube-Type Flexible and Wearable Sodium-Ion Batteries.

Science.gov (United States)

Zhu, Yun-Hai; Yuan, Shuang; Bao, Di; Yin, Yan-Bin; Zhong, Hai-Xia; Zhang, Xin-Bo; Yan, Jun-Min; Jiang, Qing

2017-04-01

To turn waste into treasure, a facile and cost-effective strategy is developed to revive electroless nickel plating wastewater and cotton-textile waste toward a novel electrode substrate. Based on the substrate, a binder-free PB@GO@NTC electrode is obtained, which exhibits superior electrochemical performance. Moreover, for the first time, a novel tube-type flexible and wearable sodium-ion battery is successfully fabricated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Visual Observation of Dissolution of Copper Ions from a Copper Electrode

Science.gov (United States)

Ikemoto, Isao; Saitou, Kouichi

2013-01-01

During electrolysis, to visually observe the conversion of a metal to its cation, either the cation or its complex ion should have a distinct color while the electrolyte solution must be colorless and transparent. A demonstration is described in which copper is used as the electrodes and sodium polyacrylate (a superabsorbent polymer) solution is…

Voltammetric determination of sodium anthraquinone-2-sulfonate using silver solid amalgam electrodes

Czech Academy of Sciences Publication Activity Database

Skalová, Štěpánka; Navrátil, Tomáš; Barek, J.; Vyskočil, V.

2017-01-01

Roč. 148, č. 3 (2017), s. 577-583 ISSN 0026-9247 Institutional support: RVO:61388955 Keywords : Anthraquinone * Drugs * Silver solid amalgam electrode * Voltammetry Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 1.282, year: 2016

Characterization of surfactant/hydrotalcite-like clay/glassy carbon modified electrodes: Oxidation of phenol

International Nuclear Information System (INIS)

Hernandez, Maria; Fernandez, Lenys; Borras, Carlos; Mostany, Jorge; Carrero, Hermes

2007-01-01

The characteristics of hydrotalcite (HT)-like clay films containing ionic and nonionic surfactants and their ability to oxidize phenol have been examined. The HT clay (Co/Al-NO 3 ) was synthesized by coprecipitation techniques and then modified with surfactants such as sodium dodecylbenzenesulfonate (SDBS), octylphenoxypolyethoxyethanol (TX100) or cetylpyridinium bromide (CPB). X-ray diffraction analysis revealed that the interlayer basal spacing varied depending on the type of surfactant retained by the HT. The presence of SDBS and CPB expanded the HT interlayer, which in the presence of TX100 did not show an appreciable change. Phenol oxidation is favored at surfactant-HT-GC modified electrodes, after a preconcentration time, compared to phenol oxidation at HT-GC or GC electrodes. Surfactant-HT-GC modified electrodes display good stability in continuous electrochemical phenol oxidation. At pH values between 6 and 10.8, both SDBS-HT-GC and TX100-HT-GC modified electrodes seem to be promising electrodes for the detection of phenol in water; while the CPB-HT-GC modified electrode should be affected by the inorganic anions

Investigating Arsenic Mobilization Mechanisms as well as Complexation Between Arsenic and Polysulfides Associated With a Bangladeshi Rice Paddy

Science.gov (United States)

Lin, T.; Kampalath, R.; Jay, J.

2009-12-01

The presence of arsenic in the groundwater has led to the largest environmental poisoning in history. Although it is a worldwide issue that affects numerous countries, including Taiwan, Bangladesh, India, China, Mexico, Peru, Australia, and the United States, the issue is of greatest concern in the West Bengal region. In the Ganges Delta, as many as 2 million people are diagnosed with arsenicosis each year. The World Health Organization (WHO) estimates 200,000 to 270,000 arsenic-induced cancer-related deaths in Bangladesh alone. More than 100 million people in the country consume groundwater that exceeds the WHO limit as 50% of the 8 million wells contain groundwater with more than 10 μg/L. Despite the tragic public health implications of this problem, we do not yet have a complete answer to the question of why dissolved arsenic concentrations are so high in the groundwater of the Ganges Delta. Since 1999, we have been intensively studying a field site in Munshiganj, Bangladesh with extremely high levels of arsenic in groundwater (up to 1.2 mg/L). Sediment cores were collected from two locations at the field site: 1) the rice paddy and 2) edge of a nearby irrigation pond. Recharge from irrigation ponds have recently been hypothesized to be an important site of arsenic mobilization. Recent work has proposed mineral dissolution under phosphorus-limited conditions as an important mechanism for arsenic mobilization. Using microcosms with paddy and pond sediment, we are comparing arsenic release via this mechanism with that resulting from reduction of iron hydroxides at our site. Concurrently, we are looking at enhanced solubility of As in the presence of polysulfides as the effects of elemental sulfur on As solubility have not been well researched. We hypothesize that the presence of elemental sulfur, and consequent formation of polysulfides, will substantially increase the solubility of orpiment in sulfidic water and that sorption of these complexes will

Comparison of reduction products from graphite oxide and graphene oxide for anode applications in lithium-ion batteries and sodium-ion batteries.

Science.gov (United States)

Sun, Yige; Tang, Jie; Zhang, Kun; Yuan, Jinshi; Li, Jing; Zhu, Da-Ming; Ozawa, Kiyoshi; Qin, Lu-Chang

2017-02-16

Hydrazine-reduced graphite oxide and graphene oxide were synthesized to compare their performances as anode materials in lithium-ion batteries and sodium-ion batteries. Reduced graphite oxide inherits the layer structure of graphite, with an average spacing between neighboring layers (d-spacing) of 0.374 nm; this exceeds the d-spacing of graphite (0.335 nm). The larger d-spacing provides wider channels for transporting lithium ions and sodium ions in the material. We showed that reduced graphite oxide as an anode in lithium-ion batteries can reach a specific capacity of 917 mA h g -1 , which is about three times of 372 mA h g -1 , the value expected for the LiC 6 structures on the electrode. This increase is consistent with the wider d-spacing, which enhances lithium intercalation and de-intercalation on the electrodes. The electrochemical performance of the lithium-ion batteries and sodium-ion batteries with reduced graphite oxide anodes show a noticeable improvement compared to those with reduced graphene oxide anodes. This improvement indicates that reduced graphite oxide, with larger interlayer spacing, has fewer defects and is thus more stable. In summary, we found that reduced graphite oxide may be a more favorable form of graphene for the fabrication of electrodes for lithium-ion and sodium-ion batteries and other energy storage devices.

Lithium polyacrylate as a binder for tin-cobalt-carbon negative electrodes in lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Li Jing [Dept. of Chemistry, Dalhousie University, Halifax, N.S. B3H 3J5 (Canada); Le, D.-B. [3M Electronic Markets Materials Division, 3M Center, St. Paul, MN 55144-1000 (United States); Ferguson, P.P. [Dept. of Physics and Atmospheric Science, Dalhousie University, Halifax, N.S. B3H 3J5 (Canada); Dahn, J.R., E-mail: jeff.dahn@dal.c [Dept. of Chemistry, Dalhousie University, Halifax, N.S. B3H 3J5 (Canada); Dept. of Physics and Atmospheric Science, Dalhousie University, Halifax, N.S. B3H 3J5 (Canada)

2010-03-01

A lithium polyacrylate (Li-PAA) binder has been developed by 3M Company that is useful with electrodes comprising alloy anode materials. This binder was used to prepare electrodes made with Sn{sub 30}Co{sub 30}C{sub 40} material prepared by mechanical attrition. The electrochemical performance of electrodes using Li-PAA binder was characterized and compared to those using sodium carboxymethyl cellulose (CMC) and polyvinylidene fluoride (PVDF) binders. The Sn{sub 30}Co{sub 30}C{sub 40} electrodes using Li-PAA and CMC binders show much smaller irreversible capacity than the ones using PVDF binder. Poor capacity retention is observed when PVDF binder is used. By contrast, the electrodes using Li-PAA binder show excellent capacity retention for Sn{sub 30}Co{sub 30}C{sub 40} materials and a specific capacity of 450 mAh/g is achieved for at least 100 cycles. The results suggest that Li-PAA is a promising binder for electrodes made from large-volume change alloy materials.

Sodium-Doped Mesoporous Ni2P2O7 Hexagonal Tablets for High-Performance Flexible All-Solid-State Hybrid Supercapacitors.

Science.gov (United States)

Wei, Chengzhen; Cheng, Cheng; Wang, Shanshan; Xu, Yazhou; Wang, Jindi; Pang, Huan

2015-08-01

A simple hydrothermal method has been developed to prepare hexagonal tablet precursors, which are then transformed into porous sodium-doped Ni2P2O7 hexagonal tablets by a simple calcination method. The obtained samples were evaluated as electrode materials for supercapacitors. Electrochemical measurements show that the electrode based on the porous sodium-doped Ni2P2O7 hexagonal tablets exhibits a specific capacitance of 557.7 F g(-1) at a current density of 1.2 A g(-1) . Furthermore, the porous sodium-doped Ni2P2O7 hexagonal tablets were successfully used to construct flexible solid-state hybrid supercapacitors. The device is highly flexible and achieves a maximum energy density of 23.4 Wh kg(-1) and a good cycling stability after 5000 cycles, which confirms that the porous sodium-doped Ni2P2 O7 hexagonal tablets are promising active materials for flexible supercapacitors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrode polarization studies in hot corrosion systems. Progress report, 1 July 1978--31 May 1979

Energy Technology Data Exchange (ETDEWEB)

Devereux, O.F.

1979-02-01

Work is reported on thermodynamic analysis of gasifier models, equilibrium calculations performed on two and thre phase equilibrium involving components of coal gas, sodium salts, and carbon. Electrode polarization studies in molten sodium carbonate and polarization tests were performed on iron, steel, nickel, and on 304 and 316 stainless steel in molten sodium carbonate under a variety of exploratory environments. Gas/metal reactions studies, initial evaluation studies iron in hydrogen-hydrogen sulfide mixtures, pertaining to a new gravimetric facility are presented. Evaluation was made of reaction kinetics from polarization. A visual regression procedure utilizing interactive computer graphics is described for the fitting of multiparameter, nonlinear equations to experimental curves.

Performances of some low-cost counter electrode materials in CdS and CdSe quantum dot-sensitized solar cells.

Science.gov (United States)

Jun, Hieng Kiat; Careem, Mohamed Abdul; Arof, Abdul Kariem

2014-02-10

Different counter electrode (CE) materials based on carbon and Cu2S were prepared for the application in CdS and CdSe quantum dot-sensitized solar cells (QDSSCs). The CEs were prepared using low-cost and facile methods. Platinum was used as the reference CE material to compare the performances of the other materials. While carbon-based materials produced the best solar cell performance in CdS QDSSCs, platinum and Cu2S were superior in CdSe QDSSCs. Different CE materials have different performance in the two types of QDSSCs employed due to the different type of sensitizers and composition of polysulfide electrolytes used. The poor performance of QDSSCs with some CE materials is largely due to the lower photocurrent density and open-circuit voltage. The electrochemical impedance spectroscopy performed on the cells showed that the poor-performing QDSSCs had higher charge-transfer resistances and CPE values at their CE/electrolyte interfaces.

Enhanced reversible lithium storage in a nano-Si/MWCNT free-standing paper electrode prepared by a simple filtration and post sintering process

International Nuclear Information System (INIS)

Yue Lu; Zhong Haoxiang; Zhang Lingzhi

2012-01-01

Graphical abstract: Nano-Si/multi-wall carbon nanotube composite paper was prepared as free-standing electrode for lithium-ion batteries by a simple filtration method using sodium carboxymethyl cellulose as a dispersing/binding agent, followed by a thermal sintering process. The prepared paper electrode exhibited a significantly improved electrochemical performance, maintaining a specific capacity of 942 mAh g −1 after 30 cycles with a capacity fade of 0.46%/cycle. - Abstract: Nano-Si/(multi-wall carbon nanotube) (Si/MWCNT) composite paper was prepared as flexible electrode for lithium ion batteries by a simple filtration method using sodium carboxymethyl cellulose (CMC) as a dispersing/binding agent, followed by a thermal sintering process. Scanning electron microscopy (SEM) showed that nanosized Si particles were dispersed homogeneously and intertwined by the MWCNT throughout the whole paper electrode. After thermal sintering, Si/MWCNT paper electrode exhibited a significantly improved flexibility with a high Si content of 35.6 wt% as compared with before sintering, and retained a specific capacity of 942 mAh g −1 after 30 cycles with a capacity fade of 0.46%/cycle.

An electrochemical cell for in operando studies of lithium/sodium batteries using a conventional x-ray powder diffractometer

DEFF Research Database (Denmark)

Shen, Yanbin; Pedersen, Erik Ejler; Christensen, Mogens

2014-01-01

An electrochemical cell has been designed for powder X-ray diffraction (PXRD) studies of lithium ion batteries (LIB) and sodium ion batteries (SIB) in operando with high time resolution using conventional powder X-ray diffractometer. The cell allows for studies of both anode and cathode electrode...... to operate and maintain. Test examples on lithium insertion/extraction in two spinel-type LIB electrode materials (Li4Ti5O12 anode and LiMn2O4 cathode) are presented as well as first results on sodium extraction from a layered SIB cathode material (Na0.84Fe0.56Mn0.44O2)....

High-pressure syntheses of lanthanide polysulfides and polyselenides LnX_1_._9 (Ln = Gd-Tm, X = S, Se)

International Nuclear Information System (INIS)

Mueller, Carola J.; Schwarz, Ulrich; Doert, Thomas

2012-01-01

The polysulfides LnS_1_._9 and polyselenides LnSe_1_._9 of the lanthanide metals from gadolinium to thulium were prepared by high-pressure high-temperature synthesis. The compounds adopt the tetragonal CeSe_1_._9 structure type in space group P4_2/n (No. 86) with lattice parameters of 8.531 Aa ≤ a ≤ 8.654 Aa and 15.563 Aa ≤ c ≤ 15.763 Aa for the sulfides and 8.869 Aa ≤ a ≤ 9.076 Aa and 16.367 Aa ≤ c ≤ 16.611 Aa for the selenides. The atomic pattern consists of puckered double slabs [LnX]"+ and planar chalcogenide layers with ten possible chalcogen positions, of which eight are occupied by chalcogen atoms forming dinuclear X_2"2"- dianions, one by a single X"2"- ion and one remaining vacant. This resembles a √5 x √5 x 2 superstructure of the ZrSSi aristotype. Structural relationships to the aristotype and the related lanthanide polychalcogenides LnX_2_-_δ (Ln = La-Tm, X = S-Te, δ = 0 - 0.3) are discussed. The samples synthesized under high-pressure conditions (p > 1 GPa) decompose slowly under release of sulfur or selenium at ambient conditions. The crystal structure of a partially degraded thulium-polysulfide sample can be described as an incommensurate variant of the original TmS_1_._9 motif. Additionally, the isostructural ternary compound Gd(S_1_-_xSe_x)_1_._9 was synthesized and characterized by powder X-ray diffraction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Solid state sodium cells. Faststof natriumbatterier

Energy Technology Data Exchange (ETDEWEB)

Skaarup, S.; West, K. [eds.

1989-04-15

The report describes the results from the project: ''Secondary Sodium Cells with Intercalation Electrodes'' which was financed by the Danish Department of Energy. The work was carried out by the Solid State Electrochemistry Group at the Technical University of Denmark which is formed by collaborators from the Institute of Physical Chemistry and Physics Laboratory III. The use of sodium has several advantages in theory compared to lithium systems: Sodium is much more abundant and lower priced than lithium, it may be easier to find solid electrolytes of sufficiently high conductivity, sodium forms no alloy with aluminium thereby making it possible to use this metal for current collectors instead of the costlier and heavier nickel. The softness of sodium metal may make it easier to achieve and maintain contact to other components in the battery during repeated cycling. This might be of importance for room temperature operation especially. Results from the project have primarily been published in the form of articles in international scientific journals and as contributions to monographs. Copies of these articles form the backbone of the report together with a short commentary to each article. Also included in the report are some general observations, as well as results that are unsuited for publication (e.g. unsuccessful experiments) but which may still contain relevant information for other experimental workers. Lastly, the report includes results on several intercalation compounds that will be published at a later stage as well as some details about the experimental equipment. The report is divided into three main sections, Intercalation Cathode Materials, Polymer Electrolytes and Battery Cycling Equipment. (AB).

3D Networked Tin Oxide/Graphene Aerogel with a Hierarchically Porous Architecture for High-Rate Performance Sodium-Ion Batteries.

Science.gov (United States)

Xie, Xiuqiang; Chen, Shuangqiang; Sun, Bing; Wang, Chengyin; Wang, Guoxiu

2015-09-07

Low-cost and sustainable sodium-ion batteries are regarded as a promising technology for large-scale energy storage and conversion. The development of high-rate anode materials is highly desirable for sodium-ion batteries. The optimization of mass transport and electron transfer is crucial in the discovery of electrode materials with good high-rate performances. Herein, we report the synthesis of 3 D interconnected SnO2 /graphene aerogels with a hierarchically porous structure as anode materials for sodium-ion batteries. The unique 3 D architecture was prepared by a facile in situ process, during which cross-linked 3 D conductive graphene networks with macro-/meso-sized hierarchical pores were formed and SnO2 nanoparticles were dispersed uniformly on the graphene surface simultaneously. Such a 3 D functional architecture not only facilitates the electrode-electrolyte interaction but also provides an efficient electron pathway within the graphene networks. When applied as anode materials in sodium-ion batteries, the as-prepared SnO2 /graphene aerogel exhibited high reversible capacity, improved cycling performance compared to SnO2 , and promising high-rate capability. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In operando PXRD study P2-NaxTMO2 cycled in a sodium ion battery

DEFF Research Database (Denmark)

Birgisson, Steinar; Shen, Yanbin; Christiansen, Troels Lindahl

Sodium ion batteries (SIB) are being considered as a cheaper and more environmentally friendly alternative to lithium ion batteries (LIB). Application of SIB is especially important in large scale electricity storage from renewable energy sources [1]. A mayor hindrance of the development of SIB...... for practical applications is that so far there are no known electrode materials with sufficiently good rate and cycling capability. Studying structural changes of electrode materials while the battery is being charged and discharged is important to gain a deeper understanding of processes affecting...... the electrode materials. This understanding can be used to optimize battery performance and understand decay mechanisms, which in turn will facilitate the development of electrode materials fit for practical application in SIB. Our research group has developed an in operando battery cell capable of following...

Ionic charge transport between blockages: Sodium cation conduction in freshly excised bulk brain tissue

Energy Technology Data Exchange (ETDEWEB)

Emin, David, E-mail: emin@unm.edu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States); Akhtari, Massoud [Semple Institutes for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 (United States); Ellingson, B. M. [Department of Radiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 (United States); Mathern, G. W. [Department of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 (United States)

2015-08-15

We analyze the transient-dc and frequency-dependent electrical conductivities between blocking electrodes. We extend this analysis to measurements of ions’ transport in freshly excised bulk samples of human brain tissue whose complex cellular structure produces blockages. The associated ionic charge-carrier density and diffusivity are consistent with local values for sodium cations determined non-invasively in brain tissue by MRI (NMR) and diffusion-MRI (spin-echo NMR). The characteristic separation between blockages, about 450 microns, is very much shorter than that found for sodium-doped gel proxies for brain tissue, >1 cm.

Water-soluble graphene grafted by poly(sodium 4-styrenesulfonate) for enhancement of electric capacitance

International Nuclear Information System (INIS)

Du Feipeng; Wang Jingjing; Tang, Chak-Yin; Tsui, Chi-Pong; Zhou Xingping; Xie Xiaolin; Liao Yonggui

2012-01-01

Water-soluble poly(sodium 4-styrenesulfonate) modified graphene (PSSS-GR) was successfully synthesized via covalently grafting poly(sodium 4-styrenesulfonate) (PSSS) on the surfaces of graphene (GR) nanosheets. The structure of PSSS-GR was investigated with Fourier transform infrared, x-ray photoelectron and Raman spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy and atomic force microscopy. The PSSS chains made the GR nanosheets fully exfoliate into a single-layer structure, and the PSSS layer on GR reached 90 wt%. PSSS chains displayed mutually repulsive effects on promoting GR sheets that were more stable in water. The performances of supercapacitors made of PSSS-GR and unmodified GR electrodes were compared using cyclic voltammetry and galvanostatic charge/discharge techniques. The results showed that PSSS is an effective binder for graphene sheets and can increase the specific capacitance of PSSS-GR based supercapacitors and improve their rate capability. The maximum specific capacitance of the PSSS-GR based supercapacitor was 210 F g −1 at 5 A g −1 , which was 166% higher than for one made of unmodified graphene electrodes. Electrochemical impedance spectroscopy demonstrated fast ion diffusion in the PSSS-GR electrode structure. PSSS-GR based supercapacitors can fulfil one of the essential requirements for potential electric energy storage applications. (paper)

Charge–discharge properties of tin dioxide for sodium-ion battery

Energy Technology Data Exchange (ETDEWEB)

Park, Jinsoo [Department of Materials and Energy Engineering, Kyungwoon University, 730 Gangdong-ro, Sandong-meon, Gumi-si, Gyeongbuk 730-739 (Korea, Republic of); Park, Jin-Woo; Han, Jeong-Hui [School of Materials Science and Engineering, RIGET, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Lee, Sang-Won [R and D 2 Team, COSMO AM and T CO., LTD., 315 Mokhaeng-dong, Chungju (Korea, Republic of); Lee, Ki-Young [Jeonyoung ECP, 637-1, Sunggok-dong, Danwon-gu, Ansan cilt, Kyunggi-do (Korea, Republic of); Ryu, Ho-Suk; Kim, Ki-Won [School of Materials Science and Engineering, RIGET, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Wang, Guoxiu [School of Chemistry and Forensic Science, University of Technology Sydney, Sydney, NSW 2007 (Australia); Ahn, Jou-Hyeon [Department of Chemical and Biological Engineering, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Hyo-Jun, E-mail: ahj@gnu.ac.kr [School of Materials Science and Engineering, RIGET, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of)

2014-10-15

Highlights: • The electrochemical reaction of SnO2 as an anode for Na-ion batteries was studied. • The SnO2 electrode delivered the initial discharge capacity of 747 mAh/g. • Alarge irreversible capacity (597 mAh/g)was observedin the first cycle. • The in-plain crack in the electrode caused the incompletereduction of SnO{sub 2}. - Abstract: Tin dioxide was investigated as an anode material for sodium-ion batteries. The Na/SnO{sub 2} cell delivered a first discharge capacity of 747 mAh/g, but the first charge capacity was 150 mAh/g. The irreversible capacity in the first cycle was examined through characterization by X-ray diffraction and scanning electron microscopy. X-ray diffraction analysis revealed that the SnO{sub 2} active material was not reduced fully to metallic Sn. Furrows and wrinkles were formed on the electrode surface owing to the volumetric expansion upon first discharge, which led to a deterioration of the electrode structure and a loss of electrical contact between the active materials. The analysis is summarized in the schematic drawing.

Role of polymeric binders on mechanical behavior and cracking resistance of silicon composite electrodes during electrochemical cycling

Science.gov (United States)

Li, Dawei; Wang, Yikai; Hu, Jiazhi; Lu, Bo; Dang, Dingying; Zhang, Junqian; Cheng, Yang-Tse

2018-05-01

This work focuses on understanding the role of various binders, including sodium alginate (SA), Nafion, and polyvinylidene fluoride (PVDF), on the mechanical behavior and cracking resistance of silicon composite electrodes during electrochemical cycling. In situ curvature measurement of bilayer electrodes, consisting of a silicon-binder-carbon black composite layer on a copper foil, is used to determine the effects of binders on bending deformation, elastic modulus, and stress on the composite electrodes. It is found that the lithiation induced curvature and the modulus of the silicon/SA electrodes are larger than those of electrodes with Nafion and PVDF as binders. Although the modulus of Nafion is smaller than that of PVDF, the curvature and the modulus of silicon/Nafion composite are larger than those of silicon/PVDF electrodes. The moduli of all three composites decrease not only during lithiation but also during delithiation. Based on the measured stress and scanning electron microscopy observations of cracking in the composite electrodes, we conclude that the stress required to crack the composite electrodes with SA and Nafion binders is considerably higher than that of the silicon/PVDF electrode during electrochemical cycling. Thus, the cracking resistance of silicon/SA and silicon/Nafion composite electrodes is higher than that of silicon/PVDF electrodes.

Nanostructured Mo-based electrode materials for electrochemical energy storage.

Science.gov (United States)

Hu, Xianluo; Zhang, Wei; Liu, Xiaoxiao; Mei, Yueni; Huang, Yunhui

2015-04-21

The development of advanced energy storage devices is at the forefront of research geared towards a sustainable future. Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport features, and attractive physicochemical properties. They have been extensively explored in various fields of energy storage and conversion. This review is focused largely on the recent progress in nanostructured Mo-based electrode materials including molybdenum oxides (MoO(x), 2 ≤ x ≤ 3), dichalconides (MoX2, X = S, Se), and oxysalts for rechargeable lithium/sodium-ion batteries, Mg batteries, and supercapacitors. Mo-based compounds including MoO2, MoO3, MoO(3-y) (0 energy storage systems because of their unique physicochemical properties, such as conductivity, mechanical and thermal stability, and cyclability. In this review, we aim to provide a systematic summary of the synthesis, modification, and electrochemical performance of nanostructured Mo-based compounds, as well as their energy storage applications in lithium/sodium-ion batteries, Mg batteries, and pseudocapacitors. The relationship between nanoarchitectures and electrochemical performances as well as the related charge-storage mechanism is discussed. Moreover, remarks on the challenges and perspectives of Mo-containing compounds for further development in electrochemical energy storage applications are proposed. This review sheds light on the sustainable development of advanced rechargeable batteries and supercapacitors with nanostructured Mo-based electrode materials.

High performance sponge-like cobalt sulfide/reduced graphene oxide hybrid counter electrode for dye-sensitized solar cells

Science.gov (United States)

Huo, Jinghao; Wu, Jihuai; Zheng, Min; Tu, Yongguang; Lan, Zhang

2015-10-01

A sponge-like cobalt sulfide/reduced graphene oxide (CoS/rGO) hybrid film is deposited on fluorine doped SnO2 (FTO) glass by electrophoretic deposition and ion exchange deposition, following by sodium borohydride and sulfuric acid solution treatment. The film is used as the counter electrode of dye-sensitized solar cells (DSSCs), and is characterized by field emission scanning electron microscopy, Raman spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and Tafel measurements. The results show that the CoS counter electrode has a sponge structure with large specific surface area, small charge-transfer resistance at the electrode/electrolyte interface. The addition of rGO further improves the electrocatalytic activity for I3- reduction, which results in the better electrocatalytic property of CoS/rGO counter electrodes than that of Pt counter electrode. Using CoS/rGO0.2 as counter electrode, the DSSC achieves a power conversion efficiency of 9.39%; which is increased by 27.93% compared with the DSSC with Pt counter electrode (7.34%).

Performance and impedance studies of thin, porous molybdenum and tungsten electrodes for the alkali metal thermoelectric converter

Science.gov (United States)

Wheeler, B. L.; Williams, R. M.; Jeffries-Nakamura, B.; Lamb, J. L.; Loveland, M. E.; Bankston, C. P.; Cole, T.

1988-01-01

Columnar, porous, magnetron-sputtered molybdenum and tungsten films show optimum performance as alkali metal thermoelectric converter electrodes at thicknesses less than 1.0 micron when used with molybdenum or nickel current collector grids. Power densities of 0.40 W/sq cm for 0.5-micron molybdenum films at 1200 K and 0.35 W/sq cm for 0.5-micron tungsten films at 1180 K were obtained at electrode maturity after 40-90 h. Sheet resistances of magnetron sputter deposited films on sodium beta-double-prime-alumina solid electrolyte (BASE) substrates were found to increase very steeply as thickness is decreased below about 0.3-double-prime 0.4-micron. The ac impedance data for these electrodes have been interpreted in terms of contributions from the bulk BASE and the porous electrode/BASE interface. Voltage profiles of operating electrodes show that the total electrode area, of electrodes with thickness less than 2.0 microns, is not utilized efficiently unless a fairly fine (about 1 x 1 mm) current collector grid is employed.

Prenatal programming of rat cortical collecting tubule sodium transport.

Science.gov (United States)

Cheng, Chih-Jen; Lozano, German; Baum, Michel

2012-03-15

Prenatal insults have been shown to lead to elevated blood pressure in offspring when they are studied as adults. Prenatal administration of dexamethasone and dietary protein deprivation have demonstrated that there is an increase in transporter abundance for a number of nephron segments but not the subunits of the epithelial sodium channel (ENaC) in the cortical collecting duct. Recent studies have shown that aldosterone is elevated in offspring of protein-deprived mothers when studied as adults, but the physiological importance of the increase in serum aldosterone is unknown. As an indirect measure of ENaC activity, we compared the natriuretic response to benzamil in offspring of mothers who ate a low-protein diet (6%) with those who ate a normal diet (20%) for the last half of pregnancy. The natriuretic response to benzamil was greater in the 6% group (821.1 ± 161.0 μmol/24 h) compared with the 20% group (279.1 ± 137.0 μmol/24 h), consistent with greater ENaC activity in vivo (P sodium transport (-1.9 ± 3.1 pmol·mm(-1)·min(-1)), the offspring of rats that ate a 6% protein diet during the last half of pregnancy had a net sodium flux of 10.7 ± 2.6 pmol·mm(-1)·min(-1) (P = 0.01) in tubules perfused in vitro. Sodium transport was measured using ion-selective electrodes, a novel technique allowing measurement of sodium in nanoliter quantities of fluid. Thus we directly demonstrate that there is prenatal programming of cortical collecting duct sodium transport.

Carbon Quantum Dot Surface-Engineered VO2 Interwoven Nanowires: A Flexible Cathode Material for Lithium and Sodium Ion Batteries.

Science.gov (United States)

Balogun, Muhammad-Sadeeq; Luo, Yang; Lyu, Feiyi; Wang, Fuxin; Yang, Hao; Li, Haibo; Liang, Chaolun; Huang, Miao; Huang, Yongchao; Tong, Yexiang

2016-04-20

The use of electrode materials in their powdery form requires binders and conductive additives for the fabrication of the cells, which leads to unsatisfactory energy storage performance. Recently, a new strategy to design flexible, binder-, and additive-free three-dimensional electrodes with nanoscale surface engineering has been exploited in boosting the storage performance of electrode materials. In this paper, we design a new type of free-standing carbon quantum dot coated VO2 interwoven nanowires through a simple fabrication process and demonstrate its potential to be used as cathode material for lithium and sodium ion batteries. The versatile carbon quantum dots that are vastly flexible for surface engineering serve the function of protecting the nanowire surface and play an important role in the diffusion of electrons. Also, the three-dimensional carbon cloth coated with VO2 interwoven nanowires assisted in the diffusion of ions through the inner and the outer surface. With this unique architecture, the carbon quantum dot nanosurface engineered VO2 electrode exhibited capacities of 420 and 328 mAh g(-1) at current density rate of 0.3 C for lithium and sodium storage, respectively. This work serves as a milestone for the potential replacement of lithium ion batteries and next generation postbatteries.

Electrode-electrolyte interface model of tripolar concentric ring electrode and electrode paste.

Science.gov (United States)

Nasrollaholhosseini, Seyed Hadi; Steele, Preston; Besio, Walter G

2016-08-01

Electrodes are used to transform ionic currents to electrical currents in biological systems. Modeling the electrode-electrolyte interface could help to optimize the performance of the electrode interface to achieve higher signal to noise ratios. There are previous reports of accurate models for single-element biomedical electrodes. In this paper we develop a model for the electrode-electrolyte interface for tripolar concentric ring electrodes (TCRE) that are used to record brain signals.

Ultrafast and Highly Reversible Sodium Storage in Zinc-Antimony Intermetallic Nanomaterials

Energy Technology Data Exchange (ETDEWEB)

Nie, Anmin [Univ. of Illinois, Chicago, IL (United States). Mechanical and Industrial Engineering Department; Gan, Li-yong [Southwest Jiaotong University, Chengdu, Sichuan, (China). Key Laboratory of Advanced Technology of Materials; Cheng, Yingchun [Nanjing Univ. of Technology (China). Institute of Advanced Materials (IAM); Tao, Xinyong [Zhejiang Univ. of Technology, Hangzhou (China). College of Materials Science and Engineering; Yuan, Yifei [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division; Sharifi-Asl, Soroosh [Univ. of Illinois, Chicago, IL (United States). Mechanical and Industrial Engineering Department; He, Kun [Univ. of Illinois, Chicago, IL (United States). Mechanical and Industrial Engineering Department; Asayesh-Ardakani, Hasti [Univ. of Illinois, Chicago, IL (United States). Mechanical and Industrial Engineering Department; Vasiraju, Venkata [Texas A& M Univ., College Station, TX (United States). Artie McFerrin Department of Chemical Engineering; Lu, Jun [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division; Mashayek, Farzad [Univ. of Illinois, Chicago, IL (United States). Mechanical and Industrial Engineering Department; Klie, Robert [Univ. of Illinois, Chicago, IL (United States). Department of Physics; Vaddiraju, Sreeram [Texas A& M Univ., College Station, TX (United States). Artie McFerrin Department of Chemical Engineering; Schwingenschlögl, Udo [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Shahbazian-Yassar, Reza [Univ. of Illinois, Chicago, IL (United States). Mechanical and Industrial Engineering Department

2015-12-17

The progress on sodium-ion battery technology faces many grand challenges, one of which is the considerably lower rate of sodium insertion/deinsertion in electrode materials due to the larger size of sodium (Na) ions and complicated redox reactions compared to the lithium-ion systems. Here, it is demonstrated that sodium ions can be reversibly stored in Zn-Sb intermetallic nanowires at speeds that can exceed 295 nm s^-1. Remarkably, these values are one to three orders of magnitude higher than the sodiation rate of other nanowires electrochemically tested with in situ transmission electron micro­scopy. It is found that the nanowires display about 161% volume expansion after the first sodiation and then cycle with an 83% reversible volume expansion. Despite their massive expansion, the nanowires can be cycled without any cracking or facture during the ultrafast sodiation/desodiation process. Additionally, most of the phases involved in the sodiation/desodiation process possess high electrical conductivity. More specifically, the NaZnSb exhibits a layered structure, which provides channels for fast Na⁺ diffusion. This observation indicates that Zn-Sb intermetallic nanomaterials offer great promise as high rate and good cycling stability anodic materials for the next generation of sodium-ion batteries.

Electro active polymers : novel bio-electrodes and implants for urinary continence

Energy Technology Data Exchange (ETDEWEB)

Rajagopalan, S.; Sawan, M.; Savadogo, O. [Ecole Polytechnique, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour les systemes electrochimiques et energetiques

2006-07-01

This paper presented a technical solution to spinal cord injuries that result in urinary bladder dysfunction. It involves miniaturized implants based on polypyrrole, an electroactive polymer, as smart drug-eluting electrodes for neural stimulation to restore bladder function. The nerve-electrode interface is the most vulnerable point in the design and operation of neuro-electronic implants. The main disadvantages are decreased impedance and protein build-up at the stimulation site due to an inflammatory reaction. Polypyrrole is a naturally conducting polymer having both electron-conducting properties as well as actuating properties, rendering it suitable as a drug-eluting electrode for a neurostimulator. Polypyrrole electrochemically coated on platinum increases biocompatibility and reduces electric impedance by increasing the surface area of the electrode. When electrically stimulated, polypyrrole also serves as a matrix to release a negatively-charged anti-inflammatory drug fosfosal. This technology may prove useful in reconstructing a severely damaged bladder through electroactive biomaterials. Polyelectrolyte gels, such as poly(sodium) acrylate, reversibly contract and relax when activated electrically or under the influx of divalent ions. These artificial muscles can be connected to a polypyrrole strain sensor to alert the microcontroller to activate the sphincter muscle, thereby creating an artificial bladder.

Solubilities of sodium nitrate, sodium nitrite, and sodium aluminate in simulated nuclear waste

International Nuclear Information System (INIS)

Reynolds, D.A.; Herting, D.L.

1984-09-01

Solubilities were determined for sodium nitrate, sodium nitrite, and sodium aluminate in synthetic nuclear waste liquor. Solubilities were determined as a function of temperature and solution composition (concentrations of sodium hydroxide, sodium nitrate, sodium nitrite, and sodium aluminate). Temperature had the greatest effect on the solubilities of sodium nitrate and sodium nitrite and a somewhat lesser effect on sodium aluminate solubility. Hydroxide had a great effect on the solubilities of all three salts. Other solution components had minor effects. 2 references, 8 figures, 11 tables

Recent advances in Alkali Metal Thermoelectric Converter (AMTEC) electrode performance and modeling. [for space power systems

Science.gov (United States)

Bankston, C. P.; Williams, R. M.; Jeffries-Nakamura, B.; Loveland, M. E.; Underwood, M. L.

1988-01-01

The Alkali Metal Thermoelectric Converter (AMTEC) is a direct energy conversion device, utilizing a high sodium vapor pressure or activity ratio across a beta-double prime-alumina solid electrolyte (BASE). This paper describes progress on the remaining scientific issue which must be resolved to demonstrate AMTEC feasibility for space power systems: a stable, high power density electrode. Two electrode systems have recently been discovered at JPL that now have the potential to meet space power requirements. One of these is a very thin sputtered molybdenum film, less than 0.5 micron thick, with overlying current collection grids. This electrode has experimentally demonstrated stable performance at 0.4-0.5 W/sq cm for hundreds of hours. Recent modeling results show that at least 0.7 W/sq cm can be achieved. The model of electrode performance now includes all loss mechanisms, including charge transfer resistances at the electrode/electrolyte interface. A second electrode composition, cosputtered platinum/tungsten, has demonstrated 0.8 W/sq cm for 160 hours. Systems studies show that a stable electrode performance of 0.6 W/sq cm will enable high efficiency space power systems.

Surface-Activated Amorphous Alloy Fuel Electrodes for Methanol Fuel Cell

OpenAIRE

Asahi, Kawashima; Koji, Hashimoto; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals

1983-01-01

Amorphous alloy electrodes for electrochemical oxidation of methanol and its derivatives were obtained by the surface activation treatment consisting of electrodeposition of zinc on as-quenched amorphous alloy substrates, heating at 200-300℃ for 30 min, and subsequently leaching of zinc in an alkaline solution. The surface activation treatment provided a new method for the preparation of a large surface area on the amorphous alloys. The best result for oxidation of methanol, sodium formate an...

Enhanced performance of lithium-sulfur batteries with an ultrathin and lightweight MoS2/carbon nanotube interlayer

Science.gov (United States)

Yan, Lingjia; Luo, Nannan; Kong, Weibang; Luo, Shu; Wu, Hengcai; Jiang, Kaili; Li, Qunqing; Fan, Shoushan; Duan, Wenhui; Wang, Jiaping

2018-06-01

Ultrathin and lightweight MoS2/carbon nanotube (CNT) interlayers are developed to effectively trap polysulfides in high-performance lithium-sulfur (Li-S) batteries. The MoS2/CNT interlayer is constructed by loading MoS2 nanosheets onto a cross-stacked CNT film. The CNT film with excellent conductivity and superior mechanical properties provides the Li-S batteries with a uniform conductive network, a supporting skeleton for the MoS2 nanosheets, as well as a physical barrier for the polysulfides. Moreover, chemical interactions and bonding between the MoS2 nanosheets and the polysulfides are evident. The electrode with the MoS2/CNT interlayer delivers an attractive specific capacity of 784 mA h g-1 at a high capacity rate of 10 C. In addition, the electrode demonstrates a high initial capacity of 1237 mA h g-1 and a capacity fade as low as -0.061% per cycle over 500 charge/discharge cycles at 0.2 C. The problem of self-discharge can also be suppressed with the introduction of the MoS2/CNT interlayer. The simple fabrication procedure, which is suitable for commercialization, and the outstanding electrochemical performance of the cells with the MoS2/CNT interlayer demonstrate a great potential for the development of high-performance Li-S batteries.

Dextran based highly conductive hydrogel polysulfide electrolyte for efficient quasi-solid-state quantum dot-sensitized solar cells

International Nuclear Information System (INIS)

Chen, Hong-Yan; Lin, Ling; Yu, Xiao-Yun; Qiu, Kang-Qiang; Lü, Xian-Yong; Kuang, Dai-Bin; Su, Cheng-Yong

2013-01-01

Highlights: ► Dextran based hydrogel is first used to prepare quasi-solid-state polysulfide electrolyte for quantum dot-sensitized solar cells. ► The ion conductivity of hydrogel electrolyte shows almost the same value as the liquid electrolyte. ► The liquid state at elevated temperature of hydrogel electrolyte allows for a good contact between electrolyte and CdS/CdSe co-sensitized TiO 2 photoanode. ► The hydrogel electrolyte based cell exhibits slightly lower power conversion efficiency than that of liquid electrolyte based cell. ► The dynamic electron transfer mechanism in hydrogel electrolyte based cell is examined in detail by EIS and CIMPS/IMVS. -- Abstract: Highly conductive hydrogel polysulfide electrolyte is first fabricated using dextran as gelator and used as quasi-solid-state electrolyte for quantum dot-sensitized solar cells (QDSSCs). The hydrogel electrolyte with gelator concentration of 15 wt% shows almost the same conductivity as the liquid one. Moreover, its liquid state at elevated temperature allow for the well penetration into the pores in electrodeposited CdS/CdSe co-sensitized TiO 2 photoanode. This gel electrolyte based QDSSC exhibits power conversion efficiency (η) of 3.23% under AG 1.5 G one sun (100 mW cm −2 ) illumination, slightly lower than that of liquid electrolyte based cell (3.69%). The dynamic electron transfer mechanism of the gel and liquid electrolyte based QDSSC are examined by electrochemical impedance spectroscopy (EIS) and controlled intensity modulated photocurrent/photovoltage spectroscopy (CIMPS/IMVS). It is found that the electron transport in gel electrolyte based cell is much faster than the liquid electrolyte based cell but it tends to recombine more easily than the latter. However, these differences fade away with increasing the light intensity, showing declining electron collection efficiency at higher light intensity illumination. As a result, a conversion efficiency of 4.58% is obtained for the gel

Action potential propagation recorded from single axonal arbors using multi-electrode arrays.

Science.gov (United States)

Tovar, Kenneth R; Bridges, Daniel C; Wu, Bian; Randall, Connor; Audouard, Morgane; Jang, Jiwon; Hansma, Paul K; Kosik, Kenneth S

2018-04-11

We report the presence of co-occurring extracellular action potentials (eAPs) from cultured mouse hippocampal neurons among groups of planar electrodes on multi-electrode arrays (MEAs). The invariant sequences of eAPs among co-active electrode groups, repeated co-occurrences and short inter-electrode latencies are consistent with action potential propagation in unmyelinated axons. Repeated eAP co-detection by multiple electrodes was widespread in all our data records. Co-detection of eAPs confirms they result from the same neuron and allows these eAPs to be isolated from all other spikes independently of spike sorting algorithms. We averaged co-occurring events and revealed additional electrodes with eAPs that would otherwise be below detection threshold. We used these eAP cohorts to explore the temperature sensitivity of action potential propagation and the relationship between voltage-gated sodium channel density and propagation velocity. The sequence of eAPs among co-active electrodes 'fingerprints' neurons giving rise to these events and identifies them within neuronal ensembles. We used this property and the non-invasive nature of extracellular recording to monitor changes in excitability at multiple points in single axonal arbors simultaneously over several hours, demonstrating independence of axonal segments. Over several weeks, we recorded changes in inter-electrode propagation latencies and ongoing changes in excitability in different regions of single axonal arbors. Our work illustrates how repeated eAP co-occurrences can be used to extract physiological data from single axons with low electrode density MEAs. However, repeated eAP co-occurrences leads to over-sampling spikes from single neurons and thus can confound traditional spike-train analysis.

Effect of Nickel Coated Multi-Walled Carbon Nanotubes on Electrochemical Performance of Lithium-Sulfur Rechargeable Batteries.

Science.gov (United States)

Wu, Xiao; Yao, Shanshan; Hou, Jinli; Jing, Maoxiang; Qian, Xinye; Shen, Xiangqian; Xiang, Jun; Xi, Xiaoming

2017-04-01

Conventional lithium-sulfur batteries suffer from severe capacity fade, which is induced by low electron conductivity and high dissolution of intermediated polysulfides. Recent studies have shown the metal (Pt, Au, Ni) as electrocatalyst of lithium polysulfides and improved the performance for lithium sulfur batteries. In this work, we present the nickel coated multi-walled carbon nanotubes (Ni-MWNTs) as additive materials for elemental sulfur positive electrodes for lithium-sulfur rechargeable batteries. Compared with MWNTs, the obtained Ni-MWNTs/sulfur composite cathode demonstrate a reversible specific capacity approaching 545 mAh after 200 cycles at a rate of 0.5C as well as improved cycling stability and excellent rate capacity. The improved electrochemical performance can be attributed to the fact the MWNTs shows a vital role on polysulfides adsorption and nickel has a catalytic effect on the redox reactions during charge–discharge process. Meanwhile, the Ni-MWNTs is a good electric conductor for sulfur cathode.

Electrochemical reduction of trinitrotoluene on core-shell tin-carbon electrodes

International Nuclear Information System (INIS)

Grigoriants, Irena; Markovsky, Boris; Persky, Rachel; Perelshtein, Ilana; Gedanken, Aharon; Aurbach, Doron; Filanovsky, Boris; Bourenko, Tatiana; Felner, Israel

2008-01-01

In this work, we studied the electrochemical process of 2,4,6-trinitrotoluene (TNT) reduction on a new type of electrodes based on a core-shell tin-carbon Sn(C) structure. The Sn(C) composite was prepared from the precursor tetramethyl-tin Sn(CH 3 ) 4 , and the product contained a core of submicron-sized tin particles uniformly enveloped with carbon shells. Cyclic voltammograms of Sn(C) electrodes in aqueous sodium chloride solutions containing TNT show three well-pronounced reduction waves in the potential range of -0.50 to -0.80 V (vs. an Ag/AgCl/Cl - reference electrode) that correspond to the multistep process of TNT reduction. Electrodes containing Sn(C) particles annealed at 800 deg. C under argon develop higher voltammetric currents of TNT reduction (comparing to the as-prepared tin-carbon material) due to stabilization of the carbon shell. It is suggested that the reduction of TNT on core-shell tin-carbon electrodes is an electrochemically irreversible process. A partial oxidation of the TNT reduction products occurred at around -0.20 V. The electrochemical response of TNT reduction shows that it is not controlled by the diffusion of the active species to/from the electrodes but rather by interfacial charge transfer and possible adsorption phenomena. The tin-carbon electrodes demonstrate significantly stable behavior for TNT reduction in NaCl solutions and provide sufficient reproducibility with no surface fouling through prolonged voltammetric cycling. It is presumed that tin nanoparticles, which constitute the core, are electrochemically inactive towards TNT reduction, but Sn or SnO 2 formed on the electrodes during TNT reduction may participate in this reaction as catalysts or carbon-modifying agents. The nitro-groups of TNT can be reduced irreversibly (via two possible paths) by three six-electron transfers, to 2,4,6-triaminotoluene, as follows from mass-spectrometric studies. The tin-carbon electrodes described herein may serve as amperometric sensors

Virtual electrodes for high-density electrode arrays

Science.gov (United States)

Cela, Carlos J.; Lazzi, Gianluca

2015-10-13

The present embodiments are directed to implantable electrode arrays having virtual electrodes. The virtual electrodes may improve the resolution of the implantable electrode array without the burden of corresponding complexity of electronic circuitry and wiring. In a particular embodiment, a virtual electrode may include one or more passive elements to help steer current to a specific location between the active electrodes. For example, a passive element may be a metalized layer on a substrate that is adjacent to, but not directly connected to an active electrode. In certain embodiments, an active electrode may be directly coupled to a power source via a conductive connection. Beneficially, the passive elements may help to increase the overall resolution of the implantable array by providing additional stimulation points without requiring additional wiring or driver circuitry for the passive elements.

Auxiliary Electrodes for Chromium Vapor Sensors

Energy Technology Data Exchange (ETDEWEB)

Fergus, Jeffrey; Shahzad, Moaiz; Britt, Tommy

2018-05-15

Measurement of chromia-containing vapors in solid oxide fuel cell systems is useful for monitoring and addressing cell degradation caused by oxidation of the chomia scale formed on alloys for interconnects and balance-of-plant components. One approach to measuring chromium is to use a solid electrolyte with an auxiliary electrode that relates the partial pressure of the chromium containing species to the mobile species in the electrolyte. One example is YCrO3 which can equilibrate with the chromium containing vapor and yttrium in yttria stabilized zirconia to establish an oxygen activity. Another is Na2CrO4 which can equilibrate with the chromium-containing vapor to establish a sodium activity.

Dialysate sodium and sodium gradient in maintenance hemodialysis: a neglected sodium restriction approach?

OpenAIRE

Munoz Mendoza, Jair; Sun, Sumi; Chertow, Glenn M.; Moran, John; Doss, Sheila; Schiller, Brigitte

2011-01-01

Background. A higher sodium gradient (dialysate sodium minus pre-dialysis plasma sodium) during hemodialysis (HD) has been associated with sodium loading; however, its role is not well studied. We hypothesized that a sodium dialysate prescription resulting in a higher sodium gradient is associated with increases in interdialytic weight gain (IDWG), blood pressure (BP) and thirst.

Assurance of sodium concentration measurement on line in water supply to the secondary system in Atucha I and II nuclear power plants

International Nuclear Information System (INIS)

Ormando, Miguel-Angel; Galarza, Guillermo-Dario

2012-09-01

Sodium measurement is used for quality control in high purity water application, to monitor break-through of mixed bed ion exchanger, condenser leaks and also to prevent caustic corrosion in turbines. The measurement principle is based on a selective electrode that responds to Nernst equation. The samples were measured in Swan's Trace Sodium/Conductivity Analyzer, Model 2114 July 1993. The aim of this work was to present a method in order to assure sodium concentration measurement on line using the ion selective method for water supply to the secondary system. Conductivity, less sensitive but more reliable than sodium analysis, is an overall quality parameter of water. It is traditionally used to back-up sodium analyzer and is sensitive to any ionic impurities. (authors)

Na2MnSiO4 as an attractive high capacity cathode material for sodium-ion battery

Science.gov (United States)

Law, Markas; Ramar, Vishwanathan; Balaya, Palani

2017-08-01

Here we report a polyanion-based cathode material for sodium-ion batteries, Na2MnSiO4, registering impressive sodium storage performances with discharge capacity of 210 mAh g-1 at an average voltage of 3 V at 0.1 C, along with excellent long-term cycling stability (500 cycles at 1 C). Insertion/extraction of ∼1.5 mol of sodium ion per formula unit of the silicate-based compound is reported and the utilisation of Mn2+ ⇋ Mn4+ redox couple is also demonstrated by ex-situ XPS. Besides, this study involves a systematic investigation of influence of the electrolyte additive (with different content) on the sodium storage performance of Na2MnSiO4. The electrolyte additive forms an optimum protective passivation film on the electrode surface, successfully reducing manganese dissolution.

Tetracaine – selective electrodes with polymer membranes and their application in pharmaceutical formulation control

Directory of Open Access Journals (Sweden)

Ahmed Khudhair Hassan

2017-02-01

Full Text Available The construction and electrochemical response characteristics of poly(vinyl chloride (PVC membrane electrodes for tetracaine hydrochloride (TCH are described. The sensing membranes incorporating ion-association complexes of tetracaine cation with phosphotungstic acid (PTA or phosphomolybdic acid (PMA or Sodium tetraphenyl borate (NaTPB as electroactive materials and di-n-butyl phthalate (DBPH or tri-n-butyl phosphate (TBP as a plasticizer in PVC matrixes were evaluated. The results obtained show the electrodes based on PTA or PMA as electroactive compounds and DBPH as plasticizer with a fast, stable and near-Nernstian response over a wide concentration range (1 × 10−5–5 × 10−2 M, with cationic slopes of 55.02 and 52.05 mV decade−1 over a pH range of (2.5–6.5. The electrodes show good discrimination of tetracaine from several inorganic cations and sugars. The electrodes were successfully applied for the determination of tetracaine in pharmaceutical formulations.

Voltammetric determination of sudan ii in food samples at graphene modified glassy carbon electrode based on the enhancement effect of sodium dodecyl sulfate

International Nuclear Information System (INIS)

Ma, X.; Chen, M.; Chao, M.

2013-01-01

Summary: Herein, a novel electrochemical method was de veloped for the determination of Sudan II based on the electrochemical catalytic activity of graphene modified glassy carbon electrode (GME) and the enhancement effect of sodium dodecyl sulfate (SDS). In a pH 6.0 phosphate buffer solution, Sudan II exhibited a pair of well-defined quasi reversible redox peaks at the GME in the presence of 5.0x10/sup -5/ mol L/sup 1/ SDS. The oxidation peak current of Sudan II was linearly proportional to its concentration in a range from 4.0x10/sup -8/ to 4.0x10/sup -6/ mol L/sup 1/, with a linear regression equation of ipa (A) = 3.35 c + 5.96 x 10/sup -6/, r = 0.9988 and a detection limit of 8.0x10/sup -9/ mol L/sup 1/. The recoveries from the standards fortified blank samples were in the range of 94.7% to 97.5% with RSD lower than 4.0%. The novel method has been successfully used to determine Sudan II in food products with satisfactory results. (author)

The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

Directory of Open Access Journals (Sweden)

Jokić Anja B.

2013-01-01

Full Text Available The application of the hydrogen-palladium electrode (H2/Pd as the indicator electrode for the determination of relative acidity scale (Es, mV of tetrahydrofuran (THF and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH, which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

Chemical sensors for monitoring non-metallic impurities in liquid sodium coolant

International Nuclear Information System (INIS)

Ganesan, Rajesh; Jayaraman, V.; Rajan Babu, S.; Sridharan, R.; Gnanasekaran, T.

2011-01-01

Liquid sodium is the coolant of choice for fast breeder reactors. Liquid sodium is highly compatible with structural steels when the concentration of dissolved non-metallic impurities such as oxygen and carbon are low. However, when their concentrations are above certain threshold limits, enhanced corrosion and mass transfer and carburization of the steels would occur. The threshold concentration levels of oxygen in sodium are determined by thermochemical aspects of various ternary oxides of Na-M-O systems (M alloying elements in steels) which take part in corrosion and mass transfer. Dissolved carbon also influences these threshold levels by establishing relevant carbide equilibria. An event of steam leak into sodium at the steam generator, if undetected at its inception itself, can lead to extensive wastage of the tubes of the steam generator and prolonged shutdown. Air ingress into the argon cover gas and leak of hydrocarbon oil used as cooling fluids of the shafts of the centrifugal pumps of sodium are the sources of oxygen and carbon impurities in sodium. Continuous monitoring of the concentration of dissolved hydrogen, carbon and oxygen in sodium coolant will help identifying their ingress at inception itself. An electrochemical hydrogen sensor based on CaHBr-CaBr 2 hydride ion conducting solid electrolyte has been developed for detecting the steam leak during normal operating conditions of the reactor. A nickel diffuser based sensor system using thermal conductivity detector (TCD) and Pd-doped tin oxide thin film sensor has been developed for use during low power operations of the reactor or during its start up. For monitoring carbon in sodium, an electrochemical sensor with molten Na 2 CO 3 -LiCO 3 as the electrolyte and pure graphite as reference electrode has been developed. Yttria Doped Thoria (YDT) electrolyte based oxygen sensor is under development for monitoring dissolved oxygen levels in sodium. Fabrication, assembly, testing and performance of

A Facile Bottom-Up Approach to Construct Hybrid Flexible Cathode Scaffold for High-Performance Lithium-Sulfur Batteries.

Science.gov (United States)

Ghosh, Arnab; Manjunatha, Revanasiddappa; Kumar, Rajat; Mitra, Sagar

2016-12-14

Lithium-sulfur batteries mostly suffer from the low utilization of sulfur, poor cycle life, and low rate performances. The prime factors that affect the performance are enormous volume change of the electrode, soluble intermediate product formation, poor electronic and ionic conductivity of S, and end discharge products (i.e., Li 2 S 2 and Li 2 S). The attractive way to mitigate these challenges underlying in the fabrication of a sulfur nanocomposite electrode consisting of different nanoparticles with distinct properties of lithium storage capability, mechanical reinforcement, and ionic as well as electronic conductivity leading to a mechanically robust and mixed conductive (ionic and electronic conductive) sulfur electrode. Herein, we report a novel bottom-up approach to synthesize a unique freestanding, flexible cathode scaffold made of porous reduced graphene oxide, nanosized sulfur, and Mn 3 O 4 nanoparticles, and all are three-dimensionally interconnected to each other by hybrid polyaniline/sodium alginate (PANI-SA) matrix to serve individual purposes. A capacity of 1098 mAh g -1 is achieved against lithium after 200 cycles at a current rate of 2 A g -1 with 97.6% of initial capacity at a same current rate, suggesting the extreme stability and cycling performance of such electrode. Interestingly, with the higher current density of 5 A g -1 , the composite electrode exhibited an initial capacity of 1015 mA h g -1 and retained 71% of the original capacity after 500 cycles. The in situ Raman study confirms the polysulfide absorption capability of Mn 3 O 4 . This work provides a new strategy to design a mechanically robust, mixed conductive nanocomposite electrode for high-performance lithium-sulfur batteries and a strategy that can be used to develop flexible large power storage devices.

Investigation of iodine liberation process in redox titration of potassium iodate with sodium thiosulfate

International Nuclear Information System (INIS)

Asakai, Toshiaki; Hioki, Akiharu

2011-01-01

Potassium iodate is often used as a reference material to standardize a sodium thiosulfate solution which is a familiar titrant for redox titrations. In the standardization, iodine (triiodide) liberated by potassium iodate in an acidic potassium iodide solution is titrated with a sodium thiosulfate solution. The iodine liberation process is significantly affected by the amount of acid, that of potassium iodide added, the waiting time for the liberation, and light; therefore, the process plays a key role for the accuracy of the titration results. Constant-voltage biamperometry with a modified dual platinum-chip electrode was utilized to monitor the amount of liberated iodine under several liberation conditions. Coulometric titration was utilized to determine the concentration of a sodium thiosulfate solution on an absolute basis. Potassium iodate was assayed by gravimetric titration with the sodium thiosulfate solution under several iodine liberation conditions. The liberation process was discussed from the changes in the apparent assay of potassium iodate. The information of the appropriate titration procedure obtained in the present study is useful for any analysts utilizing potassium iodate to standardize a thiosulfate solution.

Investigation of iodine liberation process in redox titration of potassium iodate with sodium thiosulfate

Energy Technology Data Exchange (ETDEWEB)

Asakai, Toshiaki, E-mail: t-asakai@aist.go.jp [National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 3-9, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan); Hioki, Akiharu [National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 3-9, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)

2011-03-09

Potassium iodate is often used as a reference material to standardize a sodium thiosulfate solution which is a familiar titrant for redox titrations. In the standardization, iodine (triiodide) liberated by potassium iodate in an acidic potassium iodide solution is titrated with a sodium thiosulfate solution. The iodine liberation process is significantly affected by the amount of acid, that of potassium iodide added, the waiting time for the liberation, and light; therefore, the process plays a key role for the accuracy of the titration results. Constant-voltage biamperometry with a modified dual platinum-chip electrode was utilized to monitor the amount of liberated iodine under several liberation conditions. Coulometric titration was utilized to determine the concentration of a sodium thiosulfate solution on an absolute basis. Potassium iodate was assayed by gravimetric titration with the sodium thiosulfate solution under several iodine liberation conditions. The liberation process was discussed from the changes in the apparent assay of potassium iodate. The information of the appropriate titration procedure obtained in the present study is useful for any analysts utilizing potassium iodate to standardize a thiosulfate solution.

Anti–odor activity of milk kefir on organosulphur polysulfide cyclic compounds in petai (parkia speciosa hassk)

Science.gov (United States)

Kurniati, T.; Windayani, N.; Listiawati, M.

2018-05-01

This study aims to assess the activity of milk kefir whey in neutralizing odor-causing cyclic polysulfide compounds in petai (Parkia speciosa Hassk.). RAL designs used to determine the optimum fermentation conditions. The data obtained were processed using SPSS 20. Results showed the characteristics of the microbes in the kefir grains include lactic acid bacteria consisting of genus Lactobacillus and yeast of the genus Candida and Saccharomyces. The optimum fermentation conditions using cow’s milk kefir grain starter obtained in the fermentation time of 24 hours at a concentration of 5% kefir grain. Whey kefir which is produced have high levels of fat, protein, carbohydrates, fiber and lactic acid respectively 1.81; 4.35; 5.59; 0.26 and 0.16%, pH 4.4; a density of 1.0628 g/mL and 7.9368 cP viscosity. Kefir milk whey actively reduced the level of petai smell significantly different at the level of α = 0.05.

A Nanophase-Separated, Quasi-Solid-State Polymeric Single-Ion Conductor: Polysulfide Exclusion for Lithium–Sulfur Batteries

Energy Technology Data Exchange (ETDEWEB)

Lee, Jinhong; Song, Jongchan; Lee, Hongkyung; Noh, Hyungjun; Kim, Yun-Jung; Kwon, Sung Hyun; Lee, Seung Geol; Kim, Hee-Tak

2017-04-19

Formation of soluble polysulfide (PS), which is a key feature of lithium sulfur (Li–S) batteries, provides a fast redox kinetic based on a liquid–solid mechanism; however, it imposes the critical problem of PS shuttle. Here, we address the dilemma by exploiting a solvent-swollen polymeric single-ion conductor (SPSIC) as the electrolyte medium of the Li–S battery. The SPSIC consisting of a polymeric single-ion conductor and lithium salt-free organic solvents provides Li ion hopping by forming a nanoscale conducting channel and suppresses PS shuttle according to the Donnan exclusion principle when being employed for Li–S batteries. The organic solvents at the interface of the sulfur/carbon composite and SPSIC eliminate the poor interfacial contact and function as a soluble PS reservoir for maintaining the liquid–solid mechanism. Furthermore, the quasi-solid-state SPSIC allows the fabrication of a bipolar-type stack, which promises the realization of a high-voltage and energy-dense Li–S battery.

[Applications of atomic emission spectrum from liquid electrode discharge to metal ion detection].

Science.gov (United States)

Mao, Xiu-Ling; Wu, Jian; Ying, Yi-Bin

2010-02-01

The fast and precise detection of metal ion is an important research project concerning studies in diverse academic fields and different kinds of detecting technologies. In the present paper, the authors review the research on atomic emission spectrum based on liquid electrode discharge and its applications in the detection of metal ion. In the first part of this paper the principles and characteristics of the methods based on electrochemistry and spectroscopy were introduced. The methods of ion-selective electrode (ISE), anodic stripping voltammetry, atomic emission spectrum and atomic absorption spectrum were included in this part and discussed comparatively. Then the principles and characteristics of liquid electrode spectra for metal ion detection were introduced. The mechanism of the plasma production and the characteristics of the plasma spectrum as well as its advantages compared with other methods were discussed. Secondly, the authors divided the discharge system into two types and named them single liquid-electrode discharge and double-liquid electrode respectively, according to the number of the liquid electrode and the configuration of the discharge system, and the development as well as the present research status of each type was illustrated. Then the characteristics and configurations of the discharge systems including ECGD, SCGD, LS-APGD and capillary discharge were discussed in detail as examples of the two types. By taking advantage of the technology of atomic emission spectrum based on liquid electrode discharge, the detecting limit of heavy metals such as copper, mercury and argent as well as active metal ions including sodium, potass and magnesium can achieve microg x L(-1). Finally, the advantages and problems of the liquid-electrode discharge applied in detection of metal ion were discussed. And the applications of the atomic emission spectrum based on liquid electrode discharge were prospected.

Effectiveness of Chlorinated Water, Sodium Hypochlorite, Sodium ...

African Journals Online (AJOL)

This study evaluated the efficacy of chlorinated water, sodium hypochlorite solution, sodium chloride solution and sterile distilled water in eliminating pathogenic bacteria on the surfaces of raw vegetables. Lettuce vegetables were dipped in different concentrations of chlorinated water, sodium hypochlorite solution, sodium ...

Interactions between poly(acrylic acid) and sodium dodecyl sulfate: isothermal titration calorimetric and surfactant ion-selective electrode studies.

Science.gov (United States)

Wang, C; Tam, K C

2005-03-24

Interaction between a monodispersed poly(acrylic acid) (PAA) (M(W) = 5670 g/mol, M(w)/M(n) = 1.02) with sodium dodecyl sulfate (SDS) was investigated using isothermal titration calorimetry (ITC), ion-selective electrode (ISE), and dynamic light scattering measurements. Contrary to previous studies, we report for the first time evidence of interaction between SDS and PAA when the degree of neutralization (alpha) of PAA is lower than 0.2. Hydrocarbon chains of SDS cooperatively bind to apolar segments of PAA driven by hydrophobic interaction. The interaction is both enthalpy and entropy favored (deltaH is negative but deltaS is positive). In 0.05 wt % PAA solution, the SDS concentration corresponding to the onset of binding (i.e., CAC) is approximately 2.4 mM and the saturation concentration (i.e., C(S)) is approximately 13.3 mM when alpha = 0. When PAA was neutralized and ionized, the binding was hindered by the enhanced electrostatic repulsion between negatively charged SDS and PAA chains and improved solubility of the polymer. With increasing alpha to 0.2, CAC increases to approximately 6.2 mM, C(S) drops to 8.6 mM, and the interaction is significantly weakened where the amount of bound SDS on PAA is reduced considerably. The values of CAC and C(S) derived from different techniques are in good agreement. The binding results in the formation of mixed micelles on apolar PAA coils, which then expands and dissociates into single PAA chains. The majority of unneutralized PAA molecules exist as single polymer chains stabilized by bound SDS micelles in solution after the saturation concentration.

Optimizing the surfactant for the aqueous processing of LiFePO{sub 4} composite electrodes

Energy Technology Data Exchange (ETDEWEB)

Porcher, W.; Jouanneau, S. [Commissariat a l' Energie Atomique, 38054 Grenoble Cedex 9 (France); Lestriez, B.; Guyomard, D. [Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes, CNRS, 44322 Nantes Cedex 3 (France)

2010-05-01

Aqueous processing would reduce the costs associated with the making of the composite electrode. To achieve the incorporation and the dispersion of the carbon black (CB) conductive agent in aqueous slurries, a surfactant is needed. In this paper, three surfactants are compared, an anionic one, the sodium dodecyle sulphate (SDS), a non-ionic one, the isooctylphenylether of polyoxyethylene called commercially Triton X-100 and a cationic one, the hexadecyltrimethylammonium bromide (CTAB), by using rheology and laser granulometry measurements on electrode slurries on one hand, and SEM observations, porosity and adhesion measurements and electrochemical testing on composite electrodes on the other hand. Ionic surfactants were found to be not suitable because a corrosion of the aluminium current collector occurred. The utilization of Triton X-100 favoured a more homogeneous CB distribution, resulted in a better electronic wiring of the active material particles and higher rate behavior of the electrode. Optimal electrochemical performances are obtained for an optimal surfactant concentration which depends on the BET surface area of the CB powder. (author)

Scalable Approach To Construct Free-Standing and Flexible Carbon Networks for Lithium–Sulfur Battery

KAUST Repository

Li, Mengliu

2017-02-21

Reconstructing carbon nanomaterials (e.g., fullerene, carbon nanotubes (CNTs), and graphene) to multidimensional networks with hierarchical structure is a critical step in exploring their applications. Herein, a sacrificial template method by casting strategy is developed to prepare highly flexible and free-standing carbon film consisting of CNTs, graphene, or both. The scalable size, ultralight and binder-free characteristics, as well as the tunable process/property are promising for their large-scale applications, such as utilizing as interlayers in lithium-sulfur battery. The capability of holding polysulfides (i.e., suppressing the sulfur diffusion) for the networks made from CNTs, graphene, or their mixture is pronounced, among which CNTs are the best. The diffusion process of polysulfides can be visualized in a specially designed glass tube battery. X-ray photoelectron spectroscopy analysis of discharged electrodes was performed to characterize the species in electrodes. A detailed analysis of lithium diffusion constant, electrochemical impedance, and elementary distribution of sulfur in electrodes has been performed to further illustrate the differences of different carbon interlayers for Li-S batteries. The proposed simple and enlargeable production of carbon-based networks may facilitate their applications in battery industry even as a flexible cathode directly. The versatile and reconstructive strategy is extendable to prepare other flexible films and/or membranes for wider applications.

OXYGEN BUBBLE DEVELOPMENT ON A PLATINUM ELECTRODE IN BOROSILICATE GLASS MELT BY THE EFFECT OF ALTERNATING CURRENT

Directory of Open Access Journals (Sweden)

Jiri Matej

2014-10-01

or on alternating reduction and re-forming of oxidic layer on the electrode in the transition range, has been suggested. Start of bubble evolution at low alternating current density has also been observed in simple sodium-calcium-silicate glass melt. A relation between bubble release and platinum corrosion caused by reduced silicon has been suggested

Performance Enhancement of a Sulfur/Carbon Cathode by Polydopamine as an Efficient Shell for High-Performance Lithium-Sulfur Batteries.

Science.gov (United States)

Zhang, Xuqing; Xie, Dong; Zhong, Yu; Wang, Donghuang; Wu, Jianbo; Wang, Xiuli; Xia, Xinhui; Gu, Changdong; Tu, Jiangping

2017-08-04

Lithium-sulfur batteries (LSBs) are considered to be among the most promising next-generation high-energy batteries. It is a consensus that improving the conductivity of sulfur cathodes and impeding the dissolution of lithium polysulfides are two key accesses to high-performance LSBs. Herein we report a sulfur/carbon black (S/C) cathode modified by self-polymerized polydopamine (pDA) with the assistance of polymerization treatment. The pDA acts as a novel and effective shell on the S/C cathode to stop the shuttle effect of polysulfides. By the synergistic effect of enhanced conductivity and multiple blocking effect for polysulfides, the S/C@pDA electrode exhibits improved electrochemical performances including large specific capacity (1135 mAh g -1 at 0.2 C), high rate capability (533 mAh g -1 at 5 C) and long cyclic life (965 mAh g -1 after 200 cycles). Our smart design strategy may promote the development of high-performance LSBs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Quantitative Tunneling/Desorption Model for the Exchange Current at the Porous Electrode/Beta - Alumina/Alkali Metal Gas Three Phase Zone at 700-1300K

Science.gov (United States)

Williams, R. M.; Ryan, M. A.; Saipetch, C.; LeDuc, H. G.

1996-01-01

The exchange current observed at porous metal electrodes on sodium or potassium beta -alumina solid electrolytes in alkali metal vapor is quantitatively modeled with a multi-step process with good agreement with experimental results.

Facile Assembly of 3D Porous Reduced Graphene Oxide/Ultrathin MnO2 Nanosheets-S Aerogels as Efficient Polysulfide Adsorption Sites for High-Performance Lithium-Sulfur Batteries.

Science.gov (United States)

Zhao, Xiaojun; Wang, Hui; Zhai, Gaohong; Wang, Gang

2017-05-23

Rechargeable lithium-sulfur (Li-S) batteries are receiving much attention due to their high specific capacity, low cost, and environmental friendliness. Nonetheless, fast capacity decay and low specific capacity still limit their practical implementation. Herein, we report a facile strategy to overcome these challenges by the design and fabrication of 3D porous reduced graphene oxide/ultrathin MnO 2 nanosheets-S aerogel (rGM-SA) composites for Li-S batteries. By a simple solvothermal reaction process, nanosized S atoms are homogeneously decorated into the 3D scaffold formed by reduced graphene oxide (rGO) and MnO 2 nanosheets, which can form the homogeneous rGM-SA composites. In this porous network architecture, rGO serves as an electron and ion transfer pathway, a physical adsorption site for polysulfides, and provides structural stability. The ultrathin MnO 2 nanosheets provide strong binding sites for trapping polysulfide intermediates. The 3D porous rGO/MnO 2 architecture enables rapid ion transport and buffers volume expansion of sulfur during discharge. The rGM-SA composites can be directly used as lithium-sulfur battery cathodes without using binder and conductive additive. As a result of this multifunctional arrangement, the rGM-SA composites exhibit high and stable-specific capacities over 200 cycles and excellent high-rate performances. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrafast and Highly Reversible Sodium Storage in Zinc-Antimony Intermetallic Nanomaterials

KAUST Repository

Nie, Anmin

2015-12-17

The progress on sodium-ion battery technology faces many grand challenges, one of which is the considerably lower rate of sodium insertion/deinsertion in electrode materials due to the larger size of sodium (Na) ions and complicated redox reactions compared to the lithium-ion systems. Here, it is demonstrated that sodium ions can be reversibly stored in Zn-Sb intermetallic nanowires at speeds that can exceed 295 nm s-1. Remarkably, these values are one to three orders of magnitude higher than the sodiation rate of other nanowires electrochemically tested with in situ transmission electron microscopy. It is found that the nanowires display about 161% volume expansion after the first sodiation and then cycle with an 83% reversible volume expansion. Despite their massive expansion, the nanowires can be cycled without any cracking or facture during the ultrafast sodiation/desodiation process. In addition, most of the phases involved in the sodiation/desodiation process possess high electrical conductivity. More specifically, the NaZnSb exhibits a layered structure, which provides channels for fast Na+ diffusion. This observation indicates that Zn-Sb intermetallic nanomaterials offer great promise as high rate and good cycling stability anodic materials for the next generation of sodium-ion batteries. Sodium ions can be stored in Zn4 Sb3 nanowires with a speed of 295.5 nm/s, which is one to three orders of magnitude higher than that of other nanowires electrochemically tested by the same method. Despite their massive expansion, the nanowires can be cycled dozens of times without any internal fracture during the ultrafast sodiation/desodiation process. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Voltammetric behavior of sedative drug midazolam at glassy carbon electrode in solubilized systems

Directory of Open Access Journals (Sweden)

Rajeev Jain

2012-04-01

Full Text Available Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems, supporting electrolytes and pH using differential pulse, square-wave and cyclic voltammetry. Based on its reduction behavior, a direct differential pulse voltammetric method has been developed and validated for the determination of midazolam in parenteral dosage. Three well-defined peaks were observed in 0.1% SLS, Britton–Robinson (BR buffer of pH 2.5. The effect of surfactants like sodium lauryl sulfate (SLS, cetyl trimethyl ammonium bromide (CTAB and Tween 20 was studied. Among these surfactants SLS showed significant enhancement in reduction peak. The cathodic peak currents were directly proportional to the concentration of midazolam with correlation coefficient of 0.99. Keywords: Midazolam, Voltammetry, Surfactant, Glassy carbon electrode, Parenteral dosage form

REACTION PRODUCTS AND CORROSION OF MOLYBDENUM ELECTRODE IN GLASS MELT CONTAINING ANTIMONY OXIDES AND SODIUM SULFATE

Directory of Open Access Journals (Sweden)

JIŘÍ MATĚJ

2012-09-01

Full Text Available The products on the interface of a molybdenum electrode and glass melt were investigated primarily at 1400°C in three model glass melts without ingredients, with 1 % Sb2O3 and with 1 % Sb2O3 and 0.5 % SO3 (wt. %, both under and without load by alternating current. Corrosion of the molybdenum electrode in glass melt without AC load is higher by one order of magnitude if antimony oxides are present. The corrosion continues to increase if sulfate is present in addition to antimony oxides. Isolated antimony droplets largely occur on the electrode-glass melt interface, and numerous droplets are also dissipated in the surrounding glass if only antimony oxides are present in the glass melt. A comparatively continuous layer of antimony occurs on the interface if SO3 is also present, antimony being always in contact with molybdenum sulfide. Almost no antimony droplets are dissipated in the glass melt. The total amount of precipitated antimony also increases. The presence of sulfide on the interface likely facilitates antimony precipitation. The reaction of molybdenum with antimony oxides is inhibited in sites covered by an antimony layer. The composition of sulfide layers formed at 1400°C approximates that of Mo2S3. At 1100°C, the sulfide composition approximates that of MoS4. Corrosion multiplies in the glass melt without additions through the effect of AC current, most molybdenum being separated in the form of metallic particles. Corrosion also increases in the glass melt containing antimony oxides. This is due to increased corrosion in the neighborhood of the separated antimony droplets. This mechanism also results in the loosening of molybdenum particles. The amount of precipitated antimony also increases through the effect of the AC current. AC exerts no appreciable effect on either corrosion, the character of the electrode-glass interface, or antimony precipitation in the glass melt containing SO3.

Study on preparation of SnO2-TiO2/Nano-graphite composite anode and electro-catalytic degradation of ceftriaxone sodium.

Science.gov (United States)

Guo, Xiaolei; Wan, Jiafeng; Yu, Xiujuan; Lin, Yuhui

2016-12-01

In order to improve the electro-catalytic activity and catalytic reaction rate of graphite-like material, Tin dioxide-Titanium dioxide/Nano-graphite (SnO 2 -TiO 2 /Nano-G) composite was synthesized by a sol-gel method and SnO 2 -TiO 2 /Nano-G electrode was prepared in hot-press approach. The composite was characterized by X-ray photoelectron spectroscopy, fourier transform infrared, Raman, N 2 adsorption-desorption, scanning electrons microscopy, transmission electron microscopy and X-ray diffraction. The electrochemical performance of the SnO 2 -TiO 2 /Nano-G anode electrode was investigated via cyclic voltammetry and electrochemical impedance spectroscopy. The electro-catalytic performance was evaluated by the degradation of ceftriaxone sodium and the yield of ·OH radicals in the reaction system. The results demonstrated that TiO 2 , SnO 2 and Nano-G were composited successfully, and TiO 2 and SnO 2 particles dispersed on the surface and interlamination of the Nano-G uniformly. The specific surface area of SnO 2 modified anode was higher than that of TiO 2 /Nano-G anode and the degradation rate of ceftriaxone sodium within 120 min on SnO 2 -TiO 2 /Nano-G electrode was 98.7% at applied bias of 2.0 V. The highly efficient electro-chemical property of SnO 2 -TiO 2 /Nano-G electrode was attributed to the admirable conductive property of the Nano-G and SnO 2 -TiO 2 /Nano-G electrode. Moreover, the contribution of reactive species ·OH was detected, indicating the considerable electro-catalytic activity of SnO 2 -TiO 2 /Nano-G electrode. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of the Ionization Mechanism of NAD+/NADH-Modified Gold Electrodes in ToF-SIMS Analysis.

Science.gov (United States)

Hua, Xin; Zhao, Li-Jun; Long, Yi-Tao

2018-06-04

Analysis of nicotinamide adenine dinucleotide (NAD + /NADH)-modified electrodes is important for in vitro monitoring of key biological processes. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to analyze NAD + /NADH-modified gold electrodes. Interestingly, no obvious characteristic peaks of nicotinamide fragment could be observed in the mass spectra of NAD + /NADH in their neutral sodium pyrophosphate form. However, after acidification, the characteristic peaks for both NAD + and NADH were detected. This was due to the suppression effect of inner pyrophosphoric salts in both neutral molecules. Besides, it was proved that the suppression by inner salt was intramolecular. No obvious suppression was found between neighboring molecules. These results demonstrated the suppression effect of inner salts in ToF-SIMS analysis, providing useful evidence for the study of ToF-SIMS ionization mechanism of organic molecule-modified electrodes. Graphical Abstract ᅟ.

Flexible electrode belt for EIT using nanofiber web dry electrodes.

Science.gov (United States)

Oh, Tong In; Kim, Tae Eui; Yoon, Sun; Kim, Kap Jin; Woo, Eung Je; Sadleir, Rosalind J

2012-10-01

Efficient connection of multiple electrodes to the body for impedance measurement and voltage monitoring applications is of critical importance to measurement quality and practicality. Electrical impedance tomography (EIT) experiments have generally required a cumbersome procedure to attach the multiple electrodes needed in EIT. Once placed, these electrodes must then maintain good contact with the skin during measurements that may last several hours. There is usually also the need to manage the wires that run between the electrodes and the EIT system. These problems become more severe as the number of electrodes increases, and may limit the practicality and portability of this imaging method. There have been several trials describing human-electrode interfaces using configurations such as electrode belts, helmets or rings. In this paper, we describe an electrode belt we developed for long-term EIT monitoring of human lung ventilation. The belt included 16 embossed electrodes that were designed to make good contact with the skin. The electrodes were fabricated using an Ag-plated PVDF nanofiber web and metallic threads. A large contact area and padding were used behind each electrode to improve subject comfort and reduce contact impedances. The electrodes were incorporated, equally spaced, into an elasticated fabric belt. We tested the electrode belt in conjunction with the KHU Mark1 multi-frequency EIT system, and demonstrate time-difference images of phantoms and human subjects during normal breathing and running. We found that the Ag-plated PVDF nanofiber web electrodes were suitable for long-term measurement because of their flexibility and durability. Moreover, the contact impedance and stability of the Ag-plated PVDF nanofiber web electrodes were found to be comparable to similarly tested Ag/AgCl electrodes.

Voltammetric behavior of sedative drug midazolam at glassy carbon electrode in solubilized systems

OpenAIRE

Jain, Rajeev; Yadav, Rajeev Kumar

2012-01-01

Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems, supporting electrolytes and pH using differential pulse, square-wave and cyclic voltammetry. Based on its reduction behavior, a direct differential pulse voltammetric method has been developed and validated for the determination of midazolam in parenteral dosage. Three well-defined peaks were observed in 0.1% SLS, BrittonâRobinson (BR) buffer of pH 2.5. The effect of surfactants like sodium lauryl ...

Voltammetric behavior of sedative drug midazolam at glassy carbon electrode in solubilized systems

OpenAIRE

Jain, Rajeev; Yadav, Rajeev Kumar

2011-01-01

Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems, supporting electrolytes and pH using differential pulse, square-wave and cyclic voltammetry. Based on its reduction behavior, a direct differential pulse voltammetric method has been developed and validated for the determination of midazolam in parenteral dosage. Three well-defined peaks were observed in 0.1% SLS, Britton–Robinson (BR) buffer of pH 2.5. The effect of surfactants like sodium lauryl ...

Laser-Direct Writing of Silver Metal Electrodes on Transparent Flexible Substrates with High-Bonding Strength.

Science.gov (United States)

Zhou, Weiping; Bai, Shi; Ma, Ying; Ma, Delong; Hou, Tingxiu; Shi, Xiaomin; Hu, Anming

2016-09-21

We demonstrate a novel approach to rapidly fabricate conductive silver electrodes on transparent flexible substrates with high-bonding strength by laser-direct writing. A new type of silver ink composed of silver nitrate, sodium citrate, and polyvinylpyrrolidone (PVP) was prepared in this work. The role of PVP was elucidated for improving the quality of silver electrodes. Silver nanoparticles and sintered microstructures were simultaneously synthesized and patterned on a substrate using a focused 405 nm continuous wave laser. The writing was completed through the transparent flexible substrate with a programmed 2D scanning sample stage. Silver electrodes fabricated by this approach exhibit a remarkable bonding strength, which can withstand an adhesive tape test at least 50 times. After a 1500 time bending test, the resistance only increased 5.2%. With laser-induced in-situ synthesis, sintering, and simultaneous patterning of silver nanoparticles, this technology is promising for the facile fabrication of conducting electronic devices on flexible substrates.

Sodium

Science.gov (United States)

Table salt is a combination of two minerals - sodium and chloride Your body needs some sodium to work properly. It helps with the function ... in your body. Your kidneys control how much sodium is in your body. If you have too ...

Absorption spectra and cyclic voltammograms of uranium species in molten lithium molybdate-sodium molybdate eutectic at 550 C

International Nuclear Information System (INIS)

Nagai, T.; Fukushima, M.; Myochin, M.; Uehara, A.; Fujii, T.; Yamana, H.; Sato, N.

2011-01-01

Absorption spectra of uranium species dissolved in molten lithium molybdate.sodium molybdate eutectic of 0.51Li 2 MoO 4 -0.49Na 2 MoO 4 mixture at 550 C were measured by UV/Vis/NIR spectrophotometry, and their redox reactions were investigated by cyclic voltammetry. We found that the major ions of uranium species dissolved in the melt were uranyl penta-valent. After purging dry oxygen gas into the melt, pentavalent species were oxidized to the uranyl hexa-valent. In the cyclic voltammetry of the melt without uranium species, it was confirmed that the lithium-sodium molybdenum oxide compounds were deposited on the working electrode at the negative potential and the lithium molybdenum oxide compounds were deposited on the counter electrode at positive potential. When UO 2 was dissolved into the melt, the reductive reaction of the uranium species was observed at the reductive potential of the pure melt. This suggests that the uranium species dissolved in the melts could be recovered as mixed uranium-molybdenum oxides by electrolysis. (orig.)

Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries using Synchrotron Radiation Techniques

Energy Technology Data Exchange (ETDEWEB)

Mehta, Apurva; Stanford Synchrotron Radiation Lightsource; Doeff, Marca M.; Chen, Guoying; Cabana, Jordi; Richardson, Thomas J.; Mehta, Apurva; Shirpour, Mona; Duncan, Hugues; Kim, Chunjoong; Kam, Kinson C.; Conry, Thomas

2013-04-30

We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li ion and Na ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices.

Electrostatic Self-Assembly Enabling Integrated Bulk and Interfacial Sodium Storage in 3D Titania-Graphene Hybrid.

Science.gov (United States)

Xu, Gui-Liang; Xiao, Lisong; Sheng, Tian; Liu, Jianzhao; Hu, Yi-Xin; Ma, Tianyuan; Amine, Rachid; Xie, Yingying; Zhang, Xiaoyi; Liu, Yuzi; Ren, Yang; Sun, Cheng-Jun; Heald, Steve M; Kovacevic, Jasmina; Sehlleier, Yee Hwa; Schulz, Christof; Mattis, Wenjuan Liu; Sun, Shi-Gang; Wiggers, Hartmut; Chen, Zonghai; Amine, Khalil

2018-01-10

Room-temperature sodium-ion batteries have attracted increased attention for energy storage due to the natural abundance of sodium. However, it remains a huge challenge to develop versatile electrode materials with favorable properties, which requires smart structure design and good mechanistic understanding. Herein, we reported a general and scalable approach to synthesize three-dimensional (3D) titania-graphene hybrid via electrostatic-interaction-induced self-assembly. Synchrotron X-ray probe, transmission electron microscopy, and computational modeling revealed that the strong interaction between titania and graphene through comparably strong van der Waals forces not only facilitates bulk Na + intercalation but also enhances the interfacial sodium storage. As a result, the titania-graphene hybrid exhibits exceptional long-term cycle stability up to 5000 cycles, and ultrahigh rate capability up to 20 C for sodium storage. Furthermore, density function theory calculation indicated that the interfacial Li + , K + , Mg 2+, and Al 3+ storage can be enhanced as well. The proposed general strategy opens up new avenues to create versatile materials for advanced battery systems.

Electrostatic Self-Assembly Enabling Integrated Bulk and Interfacial Sodium Storage in 3D Titania-Graphene Hybrid

Energy Technology Data Exchange (ETDEWEB)

Xu, Gui-Liang [Chemical; Xiao, Lisong [Center; Sheng, Tian [Collaborative; Liu, Jianzhao [Chemical; Hu, Yi-Xin [Chemical; Department; Ma, Tianyuan [Chemical; Amine, Rachid [Materials; Xie, Yingying [Chemical; Zhang, Xiaoyi [X-ray Science; Liu, Yuzi [Nanoscience; Ren, Yang [X-ray Science; Sun, Cheng-Jun [X-ray Science; Heald, Steve M. [X-ray Science; Kovacevic, Jasmina [Center; Sehlleier, Yee Hwa [Center; Schulz, Christof [Center; Mattis, Wenjuan Liu [Microvast Power Solutions, 12603; Sun, Shi-Gang [Collaborative; Wiggers, Hartmut [Center; Chen, Zonghai [Chemical; Amine, Khalil [Chemical

2017-12-15

Room temperature sodium-ion batteries have attracted increased attention for energy storage due to the natural abundance of sodium. However, it remains a huge challenge to develop versatile electrode materials with favorable properties, which requires smart structure design and good mechanistic understanding. Herein, we reported a general and scalable approach to synthesize 3D titania-graphene hybrid via electrostatic-interaction-induced self-assembly. Synchrotron X-ray probe, transmission electron microscopy and computational modeling revealed that the strong interaction between Titania and graphene through comparably strong van-der-Waals forces not only facilitates bulk Na+ intercalation but also enhances the interfacial sodium storage. As a result, the titania-graphene hybrid exhibits exceptional long-term cycle stability up to 5000 cycles, and ultrahigh rate capability up to 20 C for sodium storage. Furthermore, density function theory calculation indicated that the interfacial Li+, K+, Mg2+ and Al3+ storage can be enhanced as well. The proposed general strategy opens up new avenues to create versatile materials for advanced battery systems.

Methodology for Extraction of Remaining Sodium of Used Sodium Containers

International Nuclear Information System (INIS)

Jung, Minhwan; Kim, Jongman; Cho, Youngil; Jeong, Jiyoung

2014-01-01

Sodium used as a coolant in the SFR (Sodium-cooled Fast Reactor) reacts easily with most elements due to its high reactivity. If sodium at high temperature leaks outside of a system boundary and makes contact with oxygen, it starts to burn and toxic aerosols are produced. In addition, it generates flammable hydrogen gas through a reaction with water. Hydrogen gas can be explosive within the range of 4.75 vol%. Therefore, the sodium should be handled carefully in accordance with standard procedures even though there is a small amount of target sodium remainings inside the containers and drums used for experiment. After the experiment, all sodium experimental apparatuses should be dismantled carefully through a series of draining, residual sodium extraction, and cleaning if they are no longer reused. In this work, a system for the extraction of the remaining sodium of used sodium drums has been developed and an operation procedure for the system has been established. In this work, a methodology for the extraction of remaining sodium out of the used sodium container has been developed as one of the sodium facility maintenance works. The sodium extraction system for remaining sodium of the used drums was designed and tested successfully. This work will contribute to an establishment of sodium handling technology for PGSFR. (Prototype Gen-IV Sodium-cooled Fast Reactor)

Greigite: a true intermediate on the polysulfide pathway to pyrite

Directory of Open Access Journals (Sweden)

Benning Liane G

2007-03-01

Full Text Available Abstract The formation of pyrite (FeS2 from iron monosulfide precursors in anoxic sediments has been suggested to proceed via mackinawite (FeS and greigite (Fe3S4. Despite decades of research, the mechanisms of pyrite formation are not sufficiently understood because solid and dissolved intermediates are oxygen-sensitive and poorly crystalline and therefore notoriously difficult to characterize and quantify. In this study, hydrothermal synchrotron-based energy dispersive X-ray diffraction (ED-XRD methods were used to investigate in situ and in real-time the transformation of mackinawite to greigite and pyrite via the polysulfide pathway. The rate of formation and disappearance of specific Bragg peaks during the reaction and the changes in morphology of the solid phases as observed with high resolution microscopy were used to derive kinetic parameters and to determine the mechanisms of the reaction from mackinawite to greigite and pyrite. The results clearly show that greigite is formed as an intermediate on the pathway from mackinawite to pyrite. The kinetics of the transformation of mackinawite to greigite and pyrite follow a zero-order rate law indicating a solid-state mechanism. The morphology of greigite and pyrite crystals formed under hydrothermal conditions supports this conclusion and furthermore implies growth of greigite and pyrite by oriented aggregation of nanoparticulate mackinawite and greigite, respectively. The activation enthalpies and entropies of the transformation of mackinawite to greigite, and of greigite to pyrite were determined from the temperature dependence of the rate constants according to the Eyring equation. Although the activation enthalpies are uncharacteristic of a solid-state mechanism, the activation entropies indicate a large increase of order in the transition state, commensurate with a solid-state mechanism.

Efficient uranium capture by polysulfide/layered double hydroxide composites.

Science.gov (United States)

Ma, Shulan; Huang, Lu; Ma, Lijiao; Shim, Yurina; Islam, Saiful M; Wang, Pengli; Zhao, Li-Dong; Wang, Shichao; Sun, Genban; Yang, Xiaojing; Kanatzidis, Mercouri G

2015-03-18

There is a need to develop highly selective and efficient materials for capturing uranium (normally as UO2(2+)) from nuclear waste and from seawater. We demonstrate the promising adsorption performance of S(x)-LDH composites (LDH is Mg/Al layered double hydroxide, [S(x)](2-) is polysulfide with x = 2, 4) for uranyl ions from a variety of aqueous solutions including seawater. We report high removal capacities (q(m) = 330 mg/g), large K(d)(U) values (10(4)-10(6) mL/g at 1-300 ppm U concentration), and high % removals (>95% at 1-100 ppm, or ∼80% for ppb level seawater) for UO2(2+) species. The S(x)-LDHs are exceptionally efficient for selectively and rapidly capturing UO2(2+) both at high (ppm) and trace (ppb) quantities from the U-containing water including seawater. The maximum adsorption coeffcient value K(d)(U) of 3.4 × 10(6) mL/g (using a V/m ratio of 1000 mL/g) observed is among the highest reported for U adsorbents. In the presence of very high concentrations of competitive ions such as Ca(2+)/Na(+), S(x)-LDH exhibits superior selectivity for UO2(2+), over previously reported sorbents. Under low U concentrations, (S4)(2-) coordinates to UO2(2+) forming anionic complexes retaining in the LDH gallery. At high U concentrations, (S4)(2-) binds to UO2(2+) to generate neutral UO2S4 salts outside the gallery, with NO3(-) entering the interlayer to form NO3-LDH. In the presence of high Cl(-) concentration, Cl(-) preferentially replaces [S4](2-) and intercalates into LDH. Detailed comparison of U removal efficiency of S(x)-LDH with various known sorbents is reported. The excellent uranium adsorption ability along with the environmentally safe, low-cost constituents points to the high potential of S(x)-LDH materials for selective uranium capture.

Effects of electrode distance and nature of electrolyte on the diameter of titanium dioxide nanotube

Energy Technology Data Exchange (ETDEWEB)

Abbasi, S., E-mail: sum.abbasi@gmail.com; Mohamed, N. M., E-mail: noranimuti-mohamed@petronas.com.my; Singh, B. S. M., E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences Unviersiti Teknologi PETRONAS, 31750, Bandar Seri Iskandar (Malaysia); Abbasi, S. H., E-mail: sarfrazabbasi@gmail.com [SABIC Plastic Application Development Center, Riyadh Technovalley, Riyadh (Saudi Arabia)

2015-07-22

The titanium nanotubes were synthesized using viscous electrolytes consisting of ethylene glycol and non-viscous electrolytes consisting of aqueous solution of hydrofluoric acid. Sodium fluoride and ammonium fluoride were utilized as the source of fluorine ions. The samples were then characterized by field emission scanning electron microscope (FE-SEM). Their morphologies were investigated under different anodic potentials and various electrolyte compositions. It was found out that nanotubes can be obtained in fluoride ions and morphology is dependent on various parameters like anodic potential, time, electrolyte composition and the effects by varying the distance between the electrodes on the morphology was also investigated. It was found that by altering the distance between the electrodes, change in the diameter and the porosity was observed.

Ionic liquids and derived materials for lithium and sodium batteries.

Science.gov (United States)

Yang, Qiwei; Zhang, Zhaoqiang; Sun, Xiao-Guang; Hu, Yong-Sheng; Xing, Huabin; Dai, Sheng

2018-03-21

The ever-growing demand for advanced energy storage devices in portable electronics, electric vehicles and large scale power grids has triggered intensive research efforts over the past decade on lithium and sodium batteries. The key to improve their electrochemical performance and enhance the service safety lies in the development of advanced electrode, electrolyte, and auxiliary materials. Ionic liquids (ILs) are liquids consisting entirely of ions near room temperature, and are characterized by many unique properties such as ultralow volatility, high ionic conductivity, good thermal stability, low flammability, a wide electrochemical window, and tunable polarity and basicity/acidity. These properties create the possibilities of designing batteries with excellent safety, high energy/power density and long-term stability, and also provide better ways to synthesize known materials. IL-derived materials, such as poly(ionic liquids), ionogels and IL-tethered nanoparticles, retain most of the characteristics of ILs while being endowed with other favourable features, and thus they have received a great deal of attention as well. This review provides a comprehensive review of the various applications of ILs and derived materials in lithium and sodium batteries including Li/Na-ion, dual-ion, Li/Na-S and Li/Na-air (O 2 ) batteries, with a particular emphasis on recent advances in the literature. Their unique characteristics enable them to serve as advanced resources, medium, or ingredient for almost all the components of batteries, including electrodes, liquid electrolytes, solid electrolytes, artificial solid-electrolyte interphases, and current collectors. Some thoughts on the emerging challenges and opportunities are also presented in this review for further development.

Electrocatalysis aqueous phenol with carbon nanotubes networks as anodes: Electrodes passivation and regeneration and prevention

International Nuclear Information System (INIS)

Gao, Guandao; Vecitis, Chad D.

2013-01-01

Highlights: ► The electrochemical filtration used carbon nanotube network is effective to remove aqueous pollutants. ► Electrodes passivation is one of the most urgent challenges to overcome to 3-D electrode technology. ► Generally running system at higher potential can avoid generating polymer. ► Washing electrodes with suitable solvents is an effective alternative for removing polymer if it is not the best. -- Abstract: Electrochemical filtration using three-dimensional carbon nanotube (CNT) networks has been reported to increase the electrooxidation rate of aqueous pollutants due to convective mass transfer enhancements resulting from the flow through the electrode. In regards to the long term application of this novel electrochemical technology, electrode passivation is one of the most important challenges to overcome. Here, electrochemical filtration of aqueous phenol in a sodium sulfate electrolyte is utilized to investigate the primary passivation mechanisms and electrode regeneration methodologies, in which chronoamperometry and effluent total organic carbon measurements are utilized to monitor the passivation process in real-time, and electrochemical impedance spectroscopy, linear sweep voltammetry, and scanning electron microscopy are utilized to examine the CNT networks before passivation, after passivation and after regeneration. Finnaly, the carbon nanotube electrode passivation mechanisms and regeneration methods are discussed. Generally it is better choice to run system at higher potential in order to avoid generating polymer firstly other than regenerate complicatedly it after its passivation. Polymer formation can be prevented by application of an anode potential ≥2.1 V, which can completely mineralize phenol to carbon dioxide etc. and prevent polymerization of phenol. If there is still a bit of polymer formed inevitably, washing electrodes with suitable solvents is an effective alternative

Sulfur cathodes with hydrogen reduced titanium dioxide inverse opal structure.

Science.gov (United States)

Liang, Zheng; Zheng, Guangyuan; Li, Weiyang; Seh, Zhi Wei; Yao, Hongbin; Yan, Kai; Kong, Desheng; Cui, Yi

2014-05-27

Sulfur is a cathode material for lithium-ion batteries with a high specific capacity of 1675 mAh/g. The rapid capacity fading, however, presents a significant challenge for the practical application of sulfur cathodes. Two major approaches that have been developed to improve the sulfur cathode performance include (a) fabricating nanostructured conductive matrix to physically encapsulate sulfur and (b) engineering chemical modification to enhance binding with polysulfides and, thus, to reduce their dissolution. Here, we report a three-dimensional (3D) electrode structure to achieve both sulfur physical encapsulation and polysulfides binding simultaneously. The electrode is based on hydrogen reduced TiO2 with an inverse opal structure that is highly conductive and robust toward electrochemical cycling. The relatively enclosed 3D structure provides an ideal architecture for sulfur and polysulfides confinement. The openings at the top surface allow sulfur infusion into the inverse opal structure. In addition, chemical tuning of the TiO2 composition through hydrogen reduction was shown to enhance the specific capacity and cyclability of the cathode. With such TiO2 encapsulated sulfur structure, the sulfur cathode could deliver a high specific capacity of ∼1100 mAh/g in the beginning, with a reversible capacity of ∼890 mAh/g after 200 cycles of charge/discharge at a C/5 rate. The Coulombic efficiency was also maintained at around 99.5% during cycling. The results showed that inverse opal structure of hydrogen reduced TiO2 represents an effective strategy in improving lithium sulfur batteries performance.

Sodium fire tests for investigating the sodium leak in Monju

International Nuclear Information System (INIS)

Seino, Hiroshi; Miyahara, Shinya; Miyake, Osamu; Tanabe, Hiromi

1996-01-01

As a part of the work for investigating the sodium leak accident which occurred in Monju on December 8, 1995, three tests, (1) sodium leak test, (2) sodium fire test-I, and (3) sodium fire test-II, were carried out at OEC/PNC. Main objectives of these tests are to confirm leak and burning behavior of sodium from the damaged thermometer, and effects of the sodium fire on integrity of the surrounding structure, etc. The main conclusions obtained from the tests are shown as below. 1) Average sodium leak rate obtained from the sodium leak test was about 50 g/sec. This was equivalent to the value estimated from level change in the sodium overflow tank in the Monju accident. 2) Observation from video cameras in the sodium fire tests revealed that in early stages of sodium leak, sodium dropped down out of the flexible tube of thermometer in drips. This dripping and burning were expanded in range as sodium splashed on the duct. 3) Though, in the sodium fire test-I, there was a decrease of about 1 mm at a thickness of the burning pan in the vicinity in just under in the leak point, there were completely no crack and failure. In the meantime, in the sodium fire test-II the six open holes were found in the floor liner. By this liner failure, the reaction between sodium and concrete might take place. At present, while the detailed evaluation on the sodium fire test-II has been mainly carried out, the investigation for clarifying the cause of the liner failure has been also carried out. (author)

Catoptric electrodes: transparent metal electrodes using shaped surfaces.

Science.gov (United States)

Kik, Pieter G

2014-09-01

An optical electrode design is presented that theoretically allows 100% optical transmission through an interdigitated metallic electrode at 50% metal areal coverage. This is achieved by redirection of light incident on embedded metal electrode lines to an angle beyond that required for total internal reflection. Full-field electromagnetic simulations using realistic material parameters demonstrate 84% frequency-averaged transmission for unpolarized illumination across the entire visible spectral range using a silver interdigitated electrode at 50% areal coverage. The redirection is achieved through specular reflection, making it nonresonant and arbitrarily broadband, provided the electrode width exceeds the optical wavelength. These findings could significantly improve the performance of photovoltaic devices and optical detectors that require high-conductivity top contacts.

Sodium technology handbook

International Nuclear Information System (INIS)

2005-09-01

This document was published as a textbook for the education and training of personnel working for operations and maintenances of sodium facilities including FBR plants and those engaged in R and D activities related to sodium technology. This handbook covers the following technical areas. Properties of sodium. Compatibilities of sodium with materials. Thermalhydraulics and structural integrity. Sodium systems and components. Sodium instrumentations. Sodium handling technology. Sodium related accident evaluation and countermeasures for FBRs. Operation, maintenance and repair technology of sodium facilities. Safety measures related to sodium. Laws, regulations and internal rules related to sodium. The plannings and discussions of the handbook were made in the Sodium Technology Education Committee organized in O-arai Engineering Center consisting of the representatives of the related departments including Tsuruga headquarters. Experts in various departments participated in writing individual technical subjects. (author)

Activated carbon electrodes: electrochemical oxidation coupled with desalination for wastewater treatment.

Science.gov (United States)

Duan, Feng; Li, Yuping; Cao, Hongbin; Wang, Yi; Crittenden, John C; Zhang, Yi

2015-04-01

The wastewater usually contains low-concentration organic pollutants and some inorganic salts after biological treatment. In the present work, the possibility of simultaneous removal of them by combining electrochemical oxidation and electrosorption was investigated. Phenol and sodium chloride were chosen as representative of organic pollutants and inorganic salts and a pair of activated carbon plate electrodes were used as anode and cathode. Some important working conditions such as oxygen concentration, applied potential and temperature were evaluated to reach both efficient phenol removal and desalination. Under optimized 2.0 V of applied potential, 38°C of temperature, and 500 mL min(-1) of oxygen flow, over 90% of phenol, 60% of TOC and 20% of salinity were removed during 300 min of electrolysis time. Phenol was removed by both adsorption and electrochemical oxidation, which may proceed directly or indirectly by chlorine and hypochlorite oxidation. Chlorophenols were detected as degradation intermediates, but they were finally transformed to carboxylic acids. Desalination was possibly attributed to electrosorption of ions in the pores of activated carbon electrodes. The charging/regeneration cycling experiment showed good stability of the electrodes. This provides a new strategy for wastewater treatment and recycling. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of MnO2 electrodes coated by Sb-doped SnO2 and their effect on electrochemical performance for supercapacitor

International Nuclear Information System (INIS)

Zhang, Yuqing; Mo, Yan

2014-01-01

Highlights: • Sb-doped SnO 2 coated MnO 2 electrodes (SS-MnO 2 electrodes) are prepared. • The capacitive property and stability of SS-MnO 2 electrode is superior to uncoated MnO 2 electrode and SnO 2 coated MnO 2 electrode. • Sb-doped SnO 2 coating enhances electrochemical performance of MnO 2 effectively. • SS-MnO 2 electrodes are desirable to become a novel electrode material for supercapacitor. - Abstract: To enhance the specific capacity and cycling stability of manganese binoxide (MnO 2 ) for supercapacitor, antimony (Sb) doped tin dioxide (SnO 2 ) is coated on MnO 2 through a sol-gel method to prepare MnO 2 electrodes, enhancing the electrochemical performance of MnO 2 electrode in sodium sulfate electrolytes. The structure and composition of SS-MnO 2 electrode are characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-Ray diffraction spectroscopy (XRD). The electrochemical performances are evaluated and researched by galvanostatic charge-discharge test, cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). The results show that SS-MnO 2 electrodes hold porous structure, displaying superior cycling stability at large current work condition in charge-discharge tests and good capacity performance at high scanning rate in CV tests. The results of EIS show that SS-MnO 2 electrodes have small internal resistance. Therefore, the electrochemical performances of MnO 2 electrodes are enhanced effectively by Sb-doped SnO 2 coating

Tris(2-ethylhexyl)phosphine oxide as an effective solvent mediator for constructing a serotonin-selective membrane electrode

International Nuclear Information System (INIS)

Ueda, Keisuke; Yonemoto, Rei; Komagoe, Keiko; Masuda, Kazufumi; Hanioka, Nobumitsu; Narimatsu, Shizuo; Katsu, Takashi

2006-01-01

A series of solvent mediators containing a phosphoryl (P=O) group, such as tris(2-ethylhexyl)phosphate, bis(2-ethylhexyl) 2-ethylhexylphosphonate, 2-ethylhexyl bis(2-ethylhexyl)phosphinate, and tris(2-ethylhexyl)phosphine oxide, were used to construct serotonin-selective membrane electrodes. We found that replacing the alkoxy groups attached to phosphorus atoms in P=O groups with alkyl groups strengthened the response of the electrode to serotonin, suppressing remarkably interference from inorganic cations, such as Na + . Thus, an electrode combining tris(2-ethylhexyl)phosphine oxide with an ion-exchanger, sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate, gave a detection limit of 9 x 10 -6 M with a slope of 55.2 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM NaH 2 PO 4 /Na 2 HPO 4 (pH 7.4). This is the best detection limit of any serotonin-selective electrode developed to date. The selectivity of this electrode for serotonin was over 10 3 times that for inorganic cations, such as Na + and K + , and lipophilic quaternary ammonium ions, such as acetylcholine and (C 2 H 5 ) 4 N + . Using the electrode, we measured the amount of serotonin released from platelets and found that the results agreed well with those obtained by a conventional fluorimetric assay of serotonin

Inhibitin: a specific inhibitor of sodium/sodium exchange in erythrocytes.

OpenAIRE

Morgan, K; Brown, R C; Spurlock, G; Southgate, K; Mir, M A

1986-01-01

An inhibitor of ouabain-insensitive sodium/sodium exchange in erythrocytes has been isolated from leukemic promyelocytes. To explore the specific effects of this inhibitor, named inhibitin, sodium transport experiments were carried out in human erythrocytes. Inhibitin reduced ouabain-insensitive bidirectional sodium transport. It did not change net sodium fluxes, had no significant effect on rubidium influx, and did not inhibit sodium-potassium-ATPase activity. The inhibitory effect of inhibi...

Cobalt phthalocyanine modified electrodes utilised in electroanalysis: nano-structured modified electrodes vs. bulk modified screen-printed electrodes.

Science.gov (United States)

Foster, Christopher W; Pillay, Jeseelan; Metters, Jonathan P; Banks, Craig E

2014-11-19

Cobalt phthalocyanine (CoPC) compounds have been reported to provide electrocatalytic performances towards a substantial number of analytes. In these configurations, electrodes are typically constructed via drop casting the CoPC onto a supporting electrode substrate, while in other cases the CoPC complex is incorporated within the ink of a screen-printed sensor, providing a one-shot economical and disposable electrode configuration. In this paper we critically compare CoPC modified electrodes prepared by drop casting CoPC nanoparticles (nano-CoPC) onto a range of carbon based electrode substrates with that of CoPC bulk modified screen-printed electrodes in the sensing of the model analytes L-ascorbic acid, oxygen and hydrazine. It is found that no "electrocatalysis" is observed towards L-ascorbic acid using either of these CoPC modified electrode configurations and that the bare underlying carbon electrode is the origin of the obtained voltammetric signal, which gives rise to useful electroanalytical signatures, providing new insights into literature reports where "electrocatalysis" has been reported with no clear control experiments undertaken. On the other hand true electrocatalysis is observed towards hydrazine, where no such voltammetric features are witnessed on the bare underlying electrode substrate.

Reaction products and corrosion of molybdenum electrode in glass melt containing antimony oxides and sodium sulfate

Czech Academy of Sciences Publication Activity Database

Matěj, J.; Langrová, Anna

2012-01-01

Roč. 56, č. 3 (2012), s. 280-285 ISSN 0862-5468 Institutional support: RVO:67985831 Keywords : antimony oxides * corrosion * glass melt * Molybdenum electrode * sulfate Subject RIV: DD - Geochemistry Impact factor: 0.418, year: 2012 http://www.ceramics-silikaty.cz/2012/pdf/2012_03_280.pdf

Novel graphene-like electrodes for capacitive deionization.

Science.gov (United States)

Li, Haibo; Zou, Linda; Pan, Likun; Sun, Zhuo

2010-11-15

Capacitive deionization (CDI) is a novel technology that has been developed for removal of charged ionic species from salty water, such as salt ions. The basic concept of CDI, as well as electrosorption, is to force charged ions toward oppositely polarized electrodes through imposing a direct electric field to form a strong electrical double layer and hold the ions. Once the electric field disappears, the ions are instantly released back to the bulk solution. CDI is an alternative low-energy consumption desalination technology. Graphene-like nanoflakes (GNFs) with relatively high specific surface area have been prepared and used as electrodes for capacitive deionization. The GNFs were synthesized by a modified Hummers' method using hydrazine for reduction. They were characterized by atomic force microscopy, N2 adsorption at 77 K and electrochemical workstation. It was found that the ratio of nitric acid and sulfuric acid plays a vital role in determining the specific surface area of GNFs. Its electrosorption performance was much better than commercial activated carbon (AC), suggesting a great potential in capacitive deionisation application. Further, the electrosorptive performance of GNFs electrodes with different bias potentials, flow rates and ionic strengths were measured and the electrosorption isotherm and kinetics were investigated. The results showed that GNFs prepared by this process had the specific surface area of 222.01 m²/g. The specific electrosorptive capacity of the GNFs was 23.18 µmol/g for sodium ions (Na+) when the initial concentration was at 25 mg/L, which was higher than that of previously reported data using graphene and AC under the same experimental condition. In addition, the equilibrium electrosorption capacity was determined as 73.47 µmol/g at 2.0 V by fitting data through the Langmuir isotherm, and the rate constant was found to be 1.01 min⁻¹ by fitting data through pseudo first-order adsorption. The results suggested that the

Layered SnS sodium ion battery anodes synthesized near room temperature

KAUST Repository

Xia, Chuan

2017-08-10

In this report, we demonstrate a simple chemical bath deposition approach for the synthesis of layered SnS nanosheets (typically 6 nm or ~10 layers thick) at very low temperature (40 °C). We successfully synthesized SnS/C hybrid electrodes using a solution-based carbon precursor coating with subsequent carbonization strategy. Our data showed that the ultrathin carbon shell was critical to the cycling stability of the SnS electrodes. As a result, the as-prepared binder-free SnS/C electrodes showed excellent performance as sodium ion battery anodes. Specifically, the SnS/C anodes delivered a reversible capacity as high as 792 mAh·g−1 after 100 cycles at a current density of 100 mA·g−1. They also had superior rate capability (431 mAh·g−1 at 3,000 mA·g−1) and stable long-term cycling performance under a high current density (345 mAh·g−1 after 500 cycles at 3 A·g−1). Our approach opens up a new route to synthesize SnS-based hybrid materials at low temperatures for energy storage and other applications. Our process will be particularly useful for chalcogenide matrix materials that are sensitive to high temperatures during solution synthesis.

Cobalt Phthalocyanine Modified Electrodes Utilised in Electroanalysis: Nano-Structured Modified Electrodes vs. Bulk Modified Screen-Printed Electrodes

Directory of Open Access Journals (Sweden)

Christopher W. Foster

2014-11-01

Full Text Available Cobalt phthalocyanine (CoPC compounds have been reported to provide electrocatalytic performances towards a substantial number of analytes. In these configurations, electrodes are typically constructed via drop casting the CoPC onto a supporting electrode substrate, while in other cases the CoPC complex is incorporated within the ink of a screen-printed sensor, providing a one-shot economical and disposable electrode configuration. In this paper we critically compare CoPC modified electrodes prepared by drop casting CoPC nanoparticles (nano-CoPC onto a range of carbon based electrode substrates with that of CoPC bulk modified screen-printed electrodes in the sensing of the model analytes L-ascorbic acid, oxygen and hydrazine. It is found that no “electrocatalysis” is observed towards L-ascorbic acid using either of these CoPC modified electrode configurations and that the bare underlying carbon electrode is the origin of the obtained voltammetric signal, which gives rise to useful electroanalytical signatures, providing new insights into literature reports where “electrocatalysis” has been reported with no clear control experiments undertaken. On the other hand true electrocatalysis is observed towards hydrazine, where no such voltammetric features are witnessed on the bare underlying electrode substrate.

Determination of fluoride in drainage by ion electrode method

International Nuclear Information System (INIS)

Terakado, Shigeru; Ochiai, Ken-ichi; Motoyama, Shigeji; Tsutsumi, Ken-ichi

1975-01-01

The fluoride ion selective electrode method for rapidly and precisely determining fluoride in drainage was studied. This method enables the analysis of the samples with fluoride concentration above 0.1 mg/l in about five minutes. Six buffer solutions were selected to compare the masking effect against aluminum. Solution A is TISAB made by dissolving 57 ml of gracial acetic acid and 10 g of sodium chloride in 500 ml of water, thereafter adjusting pH to 5.5 and diluting to 1 liter with water. Solution B is phosphoric acid solution (17 M/L). Solution C is 3 M ammonium phosphate dibasic aqueous solution. Solution D is 1 M sodium citrate aqueous solution adjusted to pH 6 with hydrochloric acid. Solution E is 0.5 M sodium phosphate dibasic aqueous solution. Solution F is 2 M ammonium phosphate monobasic aqueous solution. As a result of studying the effect of coexisting elements, the buffer solutions A,B,E and F were greatly influenced by the coexistence of aluminum, while C and D show remarkable masking effect against aluminum. The amount of interfering ions in normal drainage is so small that no problem is anticipated for D. When fluoride recovery treatment is performed, it is important in dilution measurement to confirm whether the measured values are accurate or not, because there are high and low concentrations of fluoride at the same potential. (Iwakiri, K.)

Adiabatic flame temperature of sodium combustion and sodium-water reaction

International Nuclear Information System (INIS)

Okano, Y.; Yamaguchi, A.

2001-01-01

In this paper, background information of sodium fire and sodium-water reaction accidents of LMFBR (liquid metal fast breeder reactor) is mentioned at first. Next, numerical analysis method of GENESYS is described in detail. Next, adiabatic flame temperature and composition of sodium combustion are analyzed, and affect of reactant composition, such oxygen and moisture, is discussed. Finally, adiabatic reaction zone temperature and composition of sodium-water reaction are calculated, and affects of reactant composition, sodium vaporization, and pressure are stated. Chemical equilibrium calculation program for generic chemical system (GENESYS) is developed in this study for the research on adiabatic flame temperature of sodium combustion and adiabatic reaction zone temperature of sodium-water reaction. The maximum flame temperature of the sodium combustion is 1,950 K at the standard atmospheric condition, and is not affected by the existence of moisture. The main reaction product is Na 2 O (l) , and in combustion in moist air, with NaOH (g) . The maximum reaction zone temperature of the sodium-water reaction is 1,600 K, and increases with the system pressure. The main products are NaOH (g) , NaOH (l) and H2 (g) . Sodium evaporation should be considered in the cases of sodium-rich and high pressure above 10 bar

Sodium in diet

Science.gov (United States)

Diet - sodium (salt); Hyponatremia - sodium in diet; Hypernatremia - sodium in diet; Heart failure - sodium in diet ... Too much sodium in the diet may lead to: High blood pressure in some people A serious buildup of fluid in people with heart failure , cirrhosis of ...

Flexible carbon nanofiber/polyvinylidene fluoride composite membranes as interlayers in high-performance Lithiumsbnd Sulfur batteries

Science.gov (United States)

Wang, Zhenhua; Zhang, Jing; Yang, Yuxiang; Yue, Xinyang; Hao, Xiaoming; Sun, Wang; Rooney, David; Sun, Kening

2016-10-01

Traditionally polyvinylidene fluoride membranes have been used in applications such as membrane distillation, wastewater treatment, desalination and separator fabrication. Within this work we demonstrate that a novel carbon nanofiber/polyvinylidene fluoride (CNF/PVDF) composite membrane can be used as an interlayer for Lithiumsbnd Sulfur (Lisbnd S) batteries yielding both high capacity and long cycling life. This PVDF membrane is shown to effectively separate dissolved lithium polysulfide with the high electronic conductivity CNF not only reducing the internal resistance in the sulfur cathode but also helping immobilize the polysulfide through its abundant nanospaces. The resulting Lisbnd S battery assembled with the CNF/PVDF composite membrane effectively solves the polysulfide permeation problem and exhibits excellent electrochemical performance. It is further shown that the CNF/PVDF electrode has an excellent cycling stability and retains a capacity of 768.6 mAh g-1 with a coulombic efficiency above 99% over 200 cycles at 0.5C, which is more than twice that of a cell without CNF/PVDF (374 mAh g-1). In addition, the low-cost raw materials and the simple preparation process of CNF/PVDF composite membrane is also amenable for industrial production.

Reduced Graphene Oxide Decorated Na3V2(PO43 Microspheres as Cathode Material With Advanced Sodium Storage Performance

Directory of Open Access Journals (Sweden)

Hezhang Chen

2018-05-01

Full Text Available Reduced graphene oxide (rGO sheet decorated Na3V2(PO43 (NVP microspheres were successfully synthesized by spray-drying method. The NVP microspheres were embedded by rGO sheets, and the surface of the particles were coated by rGO sheets and amorphous carbon. Thus, the carbon conductive network consisted of rGO sheets and amorphous carbon generated in the cathode material. NVP microspheres decorated with different content of rGO (about 0, 4, 8, and 12 wt% were investigated in this study. The electrochemical performance of NVP exhibited a significant enhancement after rGO introduction. The electrode containing about 8 wt% rGO (NVP/G8 showed the best rate and cycle performance. NVP/G8 electrode exhibited the discharge capacity of 64.0 mAh g−1 at 70°C, and achieved high capacity retention of 95.5% after cycling at 10°C for 100 cycles. The polarization of the electrode was inhibited by the introduction of rGO sheets. Meanwhile, compared with the pristine NVP electrode, NVP/G8 electrode exhibited small resistance and high diffusion coefficient of sodium ions.

Reversible Redox Chemistry of Azo Compounds for Sodium-Ion Batteries.

Science.gov (United States)

Luo, Chao; Xu, Gui-Liang; Ji, Xiao; Hou, Singyuk; Chen, Long; Wang, Fei; Jiang, Jianjun; Chen, Zonghai; Ren, Yang; Amine, Khalil; Wang, Chunsheng

2018-03-05

Sustainable sodium-ion batteries (SSIBs) using renewable organic electrodes are promising alternatives to lithium-ion batteries for the large-scale renewable energy storage. However, the lack of high-performance anode material impedes the development of SSIBs. Herein, we report a new type of organic anode material based on azo group for SSIBs. Azobenzene-4,4'-dicarboxylic acid sodium salt is used as a model to investigate the electrochemical behaviors and reaction mechanism of azo compound. It exhibits a reversible capacity of 170 mAh g -1 at 0.2C. When current density is increased to 20C, the reversible capacities of 98 mAh g -1 can be retained for 2000 cycles, demonstrating excellent cycling stability and high rate capability. The detailed characterizations reveal that azo group acts as an electrochemical active site to reversibly bond with Na + . The reversible redox chemistry between azo compound and Na ions offer opportunities for developing long-cycle-life and high-rate SSIBs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and electrochemical probing of water-soluble poly(sodium 4-styrenesulfonate-co-acrylic acid)-grafted multiwalled carbon nanotubes

International Nuclear Information System (INIS)

Du Feipeng; Yang Yingkui; Xie Xiaolin; Wu Kangbing; Gan Tian; Liu Lang

2008-01-01

Water-soluble poly(sodium 4-styrenesulfonate-co-acrylic acid)-grafted multiwalled carbon nanotubes (MWNT-g-P(SSS-co-AA)) with core-shell nanostructure were successfully synthesized by in situ free radical copolymerization of sodium 4-strenesulfonate (SSS) and acrylic acid (AA) in the presence of MWNTs terminated with vinyl groups; their structure was characterized by FTIR, 1 H NMR, Raman, TGA and TEM. The results showed that the thickness and content of the copolymer layer grafted onto the MWNT surface are about 7-12 nm and 82.3%, respectively. The P(SSS-co-AA) covalently grafted on MWNTs provides MWNT-g-P(SSS-co-AA) with good hydrophilicity and solubility in water. Then a novel MWNT-g-P(SSS-co-AA)-modified glassy carbon electrode was fabricated by coating; its electrochemical properties were evaluated by electrochemical probe of K 3 [Fe(CN) 6 ], and its catalytic behaviors to the electrochemical oxidation processes of dopamine (DA) and serotonin (5-HT) were investigated. Since the MWNT-g-P(SSS-co-AA)-modified electrode possesses strong electron transfer capability, high electrochemical activity and catalytic ability, it can be used in sensitive, selective, rapid and simultaneous monitoring of biomolecules

The sodium coolant

International Nuclear Information System (INIS)

Rodriguez, G.

2004-01-01

The sodium is the best appropriate coolant for the fast neutrons reactors technology. Thus the fast neutrons reactors development is intimately bound to the sodium technology. This document presents the sodium as a coolant point of view: atomic structure and characteristics, sodium impacts on the fast neutron reactors technology, chemical properties of the sodium and the consequences, quality control in a nuclear reactor, sodium treatment. (A.L.B.)

Glassy carbon electrode modified with multi-walled carbon nanotubes sensor for the quantification of antihistamine drug pheniramine in solubilized systems.

Science.gov (United States)

Jain, Rajeev; Sharma, Sanjay

2012-02-01

A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate. The experimental results suggest that the pheniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response. Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987. The limit of detection is 58.31 μg/mL. The modified electrode shows good sensitivity and repeatability.

Recent Progress in Design of Biomass-Derived Hard Carbons for Sodium Ion Batteries

Directory of Open Access Journals (Sweden)

Joanna Górka

2016-12-01

Full Text Available Sodium ion batteries (SIBs have attracted lots of attention over last few years due to the abundance and wide availability of sodium resources, making SIBs the most cost-effective alternative to the currently used lithium ion batteries (LIBs. Many efforts are underway to find effective anodes for SIBs since the commercial anode for LIBs, graphite, has shown very limited capacity for SIBs. Among many different types of carbons, hard carbons—especially these derived from biomass—hold a great deal of promise for SIB technology thanks to their constantly improving performance and low cost. The main scope of this mini-review is to present current progress in preparation of negative electrodes from biomass including aspects related to precursor types used and their impact on the final carbon characteristics (structure, texture and composition. Another aspect discussed is how certain macro- and microstructure characteristics of the materials translate to their performance as anode for Na-ion batteries. In the last part, current understanding of factors governing sodium insertion into hard carbons is summarized, specifically those that could help solve existing performance bottlenecks such as irreversible capacity, initial low Coulombic efficiency and poor rate performance.

Clues to early diagenetic sulfurization processes from mild chemical cleavage of labile sulfur-rich geomacromolecules

Science.gov (United States)

Adam, P.; Schneckenburger, P.; Schaeffer, P.; Albrecht, P.

2000-10-01

Macromolecular fractions, isolated from the solvent extract of sulfur-rich Recent (Siders Pond, USA; Lake Cadagno, Switzerland; Walvis Bay, Namibia) and immature sediments (Gibellina, Messinian of Sicily; Vena del Gesso, Messinian of Italy), were investigated by chemical degradation using sodium ethanethiolate/methyliodide. This mild reagent which cleaves polysulfide bonds to yield methylsulfides has the advantage over other methods of leaving intact other functionalities (like double bonds) and preserving sulfur atoms at their incorporation site. The method is, therefore, well-suited to the molecular level investigation of sulfur-rich macromolecules from Recent sediments containing highly functionalized polysulfide-bound subunits. In Recent anoxic sulfur-rich sediments, the release of various methylthioethers clearly demonstrates that intermolecular sulfurization of organic matter does occur at the earliest stages of diagenesis. Steroids and phytane derivatives are the major sulfurized lipids, a feature also observed in more mature sulfur-rich sediments. Several phytene derivatives, such as cis and trans 1-methylthiophyt-2-enes, as well as methylthiosteroids, including 5α- and 5β-3-(methylthio)-cholest-2-enes, were identified by comparison with synthesized standards. Steroid methylthioenolethers are released from polysulfide-bound steroid enethiols present in the macromolecular fractions. The latter, which correspond to thioketones, can be considered as intermediates in the reductive sulfurization pathway leading from steroid ketones to polysulfide-bound saturated steroid skeletons and are characterized for the first time in the present study. Thus, it could be shown that the major part of the polysulfide-bound lipids occurring in Recent sediments is apparently the result of sulfurization processes affecting carbonyls (aldehydes and ketones). The unsaturated methylthioethers obtained from Recent sediments were not present in more mature evaporitic samples, which

Sodium pool fire analysis of sodium-cooled fast reactor by calculation

International Nuclear Information System (INIS)

Yu Hong; Xu Mi; Jin Degui

2002-01-01

Theoretical models were established according to the characteristic of sodium pool fire, and the SPOOL code was created independently. Some transient processes in sodium pool fire were modeled, including chemical reaction of sodium and oxygen; sodium combustion heat transfer modes in several kids of media; production, deposition and discharge of sodium aerosol; mass and energy exchange between different media in different ventilating conditions. The important characteristic parameters were calculated, such as pressure and temperature of gas, temperature of building materials, mass concentration of sodium aerosol, and so on. The SPOOL code, which provided available safety analysis tool for sodium pool fire accidents in sodium-cooled fast reactor, was well demonstrated with experimental data

Intra-particle migration of mercury in granular polysulfide-rubber-coated activated carbon (PSR-AC)

Science.gov (United States)

Kim, Eun-Ah; Masue-Slowey, Yoko; Fendorf, Scott; Luthy, Richard G.

2011-01-01

The depth profile of mercuric ion after the reaction with polysulfide-rubber-coated activated carbon (PSR-AC) was investigated using micro-x-ray fluorescence (μ-XRF) imaging techniques and mathematical modeling. The μ-XRF results revealed that mercury was concentrated at 0~100 μm from the exterior of the particle after three months of treatment with PSR-AC in 10 ppm HgCl2 aqueous solution. The μ-X-ray absorption near edge spectroscopic (μ-XANES) analyses indicated HgS as a major mercury species, and suggested that the intra-particle mercury transport involved a chemical reaction with PSR polymer. An intra-particle mass transfer model was developed based on either a Langmuir sorption isotherm with liquid phase diffusion (Langmuir model) or a kinetic sorption with surface diffusion (kinetic sorption model). The Langmuir model predicted the general trend of mercury diffusion, although at a slower rate than observed from the μ-XRF map. A kinetic sorption model suggested faster mercury transport, which overestimated the movement of mercuric ions through an exchange reaction between the fast and slow reaction sites. Both μ-XRF and mathematical modeling results suggest mercury removal occurs not only at the outer surface of the PSR-AC particle but also at some interior regions due to a large PSR surface area within an AC particle. PMID:22133913

Assessing the high frequency behavior of non-polarizable electrodes for spectral induced polarization measurements

Science.gov (United States)

Abdulsamad, Feras; Florsch, Nicolas; Schmutz, Myriam; Camerlynck, Christian

2016-12-01

During the last decades, the usage of spectral induced polarization (SIP) measurements in hydrogeology and detecting environmental problems has been extensively increased. However, the physical mechanisms which are responsible for the induced polarization response over the usual frequency range (typically 1 mHz to 10-20 kHz) require better understanding. The phase shift observed at high frequencies is sometimes attributed to the so-called Maxwell-Wagner polarization which takes place when charges cross an interface. However, SIP measurements of tap water show a phase shift at frequencies higher than 1 kHz, where no Maxwell-Wagner polarization may occur. In this paper, we enlighten the possible origin of this phase shift and deduce its likely relationship with the types of the measuring electrodes. SIP Laboratory measurements of tap water using different types of measuring electrodes (polarizable and non-polarizable electrodes) are carried out to detect the origin of the phase shift at high frequencies and the influence of the measuring electrodes types on the observed complex resistivity. Sodium chloride is used to change the conductivity of the medium in order to quantify the solution conductivity role. The results of these measurements are clearly showing the impact of the measuring electrodes type on the measured phase spectrum while the influence on the amplitude spectrum is negligible. The phenomenon appearing on the phase spectrum at high frequency (> 1 kHz) whatever the electrode type is, the phase shows an increase compared to the theoretical response, and the discrepancy (at least in absolute value) increases with frequency, but it is less severe when medium conductivity is larger. Additionally, the frequency corner is shifted upward in frequency. The dependence of this phenomenon on the conductivity and the measuring electrodes type (electrode-electrolyte interface) seems to be due to some dielectric effects (as an electrical double layer of small

Review on anionic redox for high-capacity lithium- and sodium-ion batteries

International Nuclear Information System (INIS)

Zhao, Chenglong; Lu, Yaxiang; Hu, Yong-Sheng; Chen, Liquan; Wang, Qidi; Li, Baohua

2017-01-01

Rechargeable batteries, especially lithium-ion batteries, are now widely used as power sources for portable electronics and electric vehicles, but material innovations are still needed to satisfy the increasing demand for larger energy density. Recently, lithium- and sodium-rich electrode materials, including the A 2 MO 3 -family layered compounds (A  =  Li, Na; M  =  Mn 4+ , Ru 4+ , etc), have been extensively studied as potential high-capacity electrode materials for a cumulative cationic and anionic redox activity. Negatively charged oxide ions can potentially donate electrons to compensate for the absence of oxidable transition metals as a redox center to further increase the reversible capacity. Understanding and controlling the state-of-the-art anionic redox processes is pivotal for the design of advanced energy materials, highlighted in rechargeable batteries. Hence, experimental and theoretical approaches have been developed to consecutively study the diverting processes, states, and structures involved. In this review, we attempt to present a literature overview and provide insight into the reaction mechanism with respect to the anionic redox processes, proposing some opinions as target oriented. It is hoped that, through this discussion, the search for anionic redox electrode materials with high-capacity rechargeable batteries can be advanced, and practical applications realized as soon as possible. (topical review)

Low sodium diet (image)

Science.gov (United States)

... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, ...

Scientific Opinion on the safety evaluation of the active substances, sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate, bentonite, sodium chloride, sodium carbonate for use in active food contact materials

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EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

2013-01-01

This scientific opinion of the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of the powder mixture of the active substances sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate (FCM substance No 1009), bentonite (CAS No 1302-78-9, FCM No 393), sodium chloride (CAS No 7647-14-5, FCM No 985), sodium carbonate (CAS No 497-19-8, FCM No 1008) which are intended to be used as combined oxygen generator and carbon...

Development of sodium disposal technology. Experiment of sodium compound solidification process

International Nuclear Information System (INIS)

Matsumoto, Toshiyuki; Ohura, Masato; Yatoh, Yasuo

2007-07-01

A large amount of sodium containing radioactive waste will come up at the time of final shutdown/decommission of FBR plant. The radioactive waste is managed as solid state material in a closed can in Japan. As for the sodium, there is no established method to convert the radioactive sodium to solid waste. Further, the sodium is highly reactive. Thus, it is recommended to convert the sodium to a stable substance before the solidification process. One of the stabilizing methods is conversion of sodium into sodium hydroxide solution. These stabilization and solidification processes should be safe, economical, and efficient. In order to develop such sodium disposal technology, nonradioactive sodium was used and a basic experiment was performed. Waste-fluid Slag Solidification method was employed as the solidification process of sodium hydroxide solution. Experimental parameters were mixing ratio of the sodium hydroxide and the slag solidification material, temperature and concentration of the sodium hydroxide. The best parameters were obtained to achieve the maximum filling ratio of the sodium hydroxide under a condition of enough high compressive strength of the solidified waste. In a beaker level test, the solidified waste was kept in a long term and it was shown that there was no change of appearance, density, and also the compressive strength was kept at a target value. In a real scale test, homogeneous profiles of the density and the compressive strength were obtained. The compressive strength was higher than the target value. It was shown that the Waste-fluid Slag Solidification method can be applied to the solidification process of the sodium hydroxide solution, which was produced by the stabilization process. (author)

Reverse microemulsion synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide nanocomposites for high-performance supercapacitors and sodium ion batteries

Science.gov (United States)

Qiu, Xiaoming; Liu, Yongchang; Wang, Luning; Fan, Li-Zhen

2018-03-01

Prussian blue analogues with tunable open channels are of fundamental and technological importance for energy storage systems. Herein, a novel facile synthesis of nickel-cobalt hexacyanoferrate/reduced graphene oxide (denoted as Ni-CoHCF/rGO) nanocomposite is realized by a reverse microemulsion method. The very fine Ni-CoHCF nanoparticles (10-20 nm) are homogeneously anchored on the surface of reduced graphene oxide by electrostatic adsorption and reduced graphene oxide is well-separated by Ni-CoHCF particles. Benefiting from the combined advantages of this structure, the Ni-. It CoHCF/rGO nanocomposite can be used as electrodes for both supercapacitors and sodium ion batteries exhibits excellent pseudocapacitve performance in terms of high specific capacitance of 466 F g-1 at 0.2 A g-1 and 350 F g-1 at 10 A g-1, along with high cycling stabilities. As a cathode material for sodium ion batteries, it also demonstrates a high reversible capacity of 118 mAh g-1 at 0.1 A g-1, good rate capability, and superior cycling stability. These results suggest its potential as an efficient electrode for high-performance energy storage and renewable delivery devices.

An ultrasensitive and selective electrochemical sensor for determination of estrone 3-sulfate sodium salt based on molecularly imprinted polymer modified carbon paste electrode.

Science.gov (United States)

Song, Han; Wang, Yuli; Zhang, Lu; Tian, Liping; Luo, Jun; Zhao, Na; Han, Yajie; Zhao, Feilang; Ying, Xue; Li, Yingchun

2017-11-01

A highly sensitive and selective electrochemical sensor based on carbon paste electrode (CPE) modified with molecularly imprinted polymers (MIPs) has been developed for the determination of estrone 3-sulfate sodium salt (ESS). MIPs were prepared in polar medium via bulk polymerization and characterized by scanning electron microscopy and infrared spectroscopy. Cyclic voltammetry was performed to the study preparation process and binding behavior of the MIP-modified CPE (MIP/CPE) toward ESS. The conditions for preparing MIPs and MIP/CPE as well as ESS detection were optimized. Under the optimal experimental conditions, the detection linear range for ESS is 4 × 10 -12 to 6 × 10 -9  M with a limit of detection of 1.18 × 10 -12  M (S/N = 3). In addition, the sensor exhibits high binding affinity toward ESS over its structural analogues with excellent repeatability and stability. The fabricated MIP/CPE was then successfully employed to detect ESS in pregnant mare urine (PMU) without any pretreatment, and the average recoveries were from 99.6 to 104.9% with relative standard deviation less than 3.0%. High-performance liquid chromatography was adopted as a reference to validate the established approach in detecting ESS and their results showed good agreement. The as-prepared sensor has high potential to be a decent tool for on-site determination of ESS in PMU in a fast and convenient manner. Graphical Abstract ᅟ.

Optimization of Electrochemical Parameters for Landfill Leachate Treatment Using Charcoal Base Metallic Composite Electrode

International Nuclear Information System (INIS)

Majd Ahmed Jumaah; Mohamed Rozali Othman

2015-01-01

Landfill leachate normally contains organic and inorganic pollutants in high concentrations. Electrochemical oxidation technique is an effective method to treat landfill leachate, have high efficiency in organic pollutants degradation and ammonia removal. In this study, a cost effective charcoal base metallic composite electrode to treat landfill leachate by electrochemical oxidation was fabricated. The effects of operational parameters such as supporting electrolyte, applied voltage and electrolysis time on the removal percentage of Color, COD, NH 3 -N and total-P (PO 4 -3 ) were carried out. The results obtained show that the removal percentage of Color, COD, NH 3 -N and total- P (PO 4 -3 ) are 70, 89, 73 and 80 % respectively. Under the optimum operating condition, sodium chloride concentration of 1.5 % (w/v), applied voltage of 10 V, operating time 180 min and C 60 C G 15 Co 10 - PVC 15 electrode as an anode were used. (author)

C-Scan Performance Test of Under-Sodium ultrasonic Waveguide Sensor in Sodium

International Nuclear Information System (INIS)

Joo, Young Sang; Bae, Jin Ho; Kim, Jong Bum

2011-01-01

Reactor core and in-vessel structures of a sodium-cooled fast (SFR) are submerged in opaque liquid sodium in the reactor vessel. The ultrasonic inspection techniques should be applied for observing the in-vessel structures under hot liquid sodium. Ultrasonic sensors such as immersion sensors and rod-type waveguide sensors have developed in order to apply under-sodium viewing of the in-vessel structures of SFR. Recently the novel plate-type ultrasonic waveguide sensor has been developed for the versatile application of under-sodium viewing in SFR. In previous studies, the ultrasonic waveguide sensor module was designed and manufactured, and the feasibility study of the ultrasonic waveguide sensor was performed. To improve the performance of the ultrasonic waveguide sensor in the under-sodium application, a new concept of ultrasonic waveguide sensors with a Be coated SS304 plate is suggested for the effective generation of a leaky wave in liquid sodium and the non-dispersive propagation of A 0 -mode Lamb wave in an ultrasonic waveguide sensor. In this study, the C-scan performance of the under-sodium ultrasonic waveguide sensor in sodium has been investigated by the experimental test in sodium. The under-sodium ultrasonic waveguide sensor and the sodium test facility with a glove box system and a sodium tank are designed and manufactured to carry out the performance test of under-sodium ultrasonic waveguide sensor in sodium environment condition

Sodium safety manual

International Nuclear Information System (INIS)

Hayes, D.J.; Gardiner, R.L.

1980-09-01

The sodium safety manual is based upon more than a decade of experience with liquid sodium at Berkeley Nuclear Laboratories (BNL). It draws particularly from the expertise and experience developed in the course of research work into sodium fires and sodium water reactions. It draws also on information obtained from the UKAEA and other sodium users. Many of the broad principles will apply to other Establishments but much of the detail is specific to BNL and as a consequence its application at other sites may well be limited. Accidents with sodium are at best unpleasant and at worst lethal in an extremely painful way. The object of this manual is to help prevent sodium accidents. It is not intended to give detailed advice on specific precautions for particular situations, but rather to set out the overall strategy which will ensure that sodium activities will be pursued safely. More detail is generally conveyed to staff by the use of local instructions known as Sodium Working Procedures (SWP's) which are not reproduced in this manual although a list of current SWP's is included. Much attention is properly given to the safe design and operation of larger facilities; nevertheless evidence suggests that sodium accidents most frequently occur in small-scale work particularly in operations associated with sodium cleaning and special care is needed in all such cases. (U.K.)

Long Life Nickel Electrodes for Nickel-Hydrogen Cells: Fiber Substrates Nickel Electrodes

Science.gov (United States)

Rogers, Howard H.

2000-01-01

Samples of nickel fiber mat electrodes were investigated over a wide range of fiber diameters, electrode thickness, porosity and active material loading levels. Thickness' were 0.040, 0.060 and 0.080 inches for the plaque: fiber diameters were primarily 2, 4, and 8 micron and porosity was 85, 90, and 95%. Capacities of 3.5 in. diameter electrodes were determined in the flooded condition with both 26 and 31% potassium hydroxide solution. These capacity tests indicated that the highest capacities per unit weight were obtained at the 90% porosity level with a 4 micron diameter fiber plaque. It appeared that the thinner electrodes had somewhat better performance, consistent with sintered electrode history. Limited testing with two-positive-electrode boiler plate cells was also carried out. Considerable difficulty with constructing the cells was encountered with short circuits the major problem. Nevertheless, four cells were tested. The cell with 95% porosity electrodes failed during conditioning cycling due to high voltage during charge. Discharge showed that this cell had lost nearly all of its capacity. The other three cells after 20 conditioning cycles showed capacities consistent with the flooded capacities of the electrodes. Positive electrodes made from fiber substrates may well show a weight advantage of standard sintered electrodes, but need considerably more work to prove this statement. A major problem to be investigated is the lower strength of the substrate compared to standard sintered electrodes. Problems with welding of leads were significant and implications that the electrodes would expand more than sintered electrodes need to be investigated. Loading levels were lower than had been expected based on sintered electrode experiences and the lower loading led to lower capacity values. However, lower loading causes less expansion and contraction during cycling so that stress on the substrate is reduced.

Study of behaviour of lanthanum- and yttrium electrodes in chloride melts

International Nuclear Information System (INIS)

Shkol'nikov, S.I.; Tolypin, E.S.; Yur'ev, B.P.

1984-01-01

A study was made on the lanthanum- and yttrium behaviour in a mixture of molten potassium- and sodium chlorides at various temperatures. It is shown that the lanthanum- and yttrium behaviour in KCl-NaCl melt is similar to the behaviour of other metals. Their corrosion rate is much higher as compared to other metals and it grows rapidly with increasing melt temperature. The temperature growth by 200 deg C results in an increase in the corrosion rate almost by an order. The potentials of lanthanum- and yttrium electrodes at the instant they are immersed in the melt have more negative values than the potentials of alkali metals under similar conditions

Characterization of modified SiC@SiO2 nanocables/MnO2 and their potential application as hybrid electrodes for supercapacitors.

Science.gov (United States)

Zhang, Yujie; Chen, Junhong; Fan, Huili; Chou, Kuo-Chih; Hou, Xinmei

2015-12-14

In this research, we demonstrate a simple route for preparing SiC@SiO2 core-shell nanocables and furthermore obtain SiC@SiO2 nanocables/MnO2 as hybrid electrodes for supercapacitors using various modified methods. The modified procedure consists of mild modifications using sodium hydroxide as well as UV light irradiation and deposition of MnO2. The morphology and microstructural characteristics of the composites are investigated using XRD, XPS, FE-SEM with EDS and TEM. The results indicate that the surfaces of modified SiC@SiO2 nanocables are uniformly coated with a MnO2 thin layer. The electrochemical behaviors of the hybrid electrodes are systematically measured in a three-electrode system using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The resultant electrode presents a superb charge storage characteristic with a large specific capacitance of 276.3 F g(-1) at the current density of 0.2 A g(-1). Moreover, the hybrid electrode also displays a long cycle life with a good capacitance retention (∼92.0%) after 1000 CV cycles, exhibiting a promising potential for supercapacitors.

Amperometric Determination of Sulfite by Gas Diffusion- Sequential Injection with Boron-Doped Diamond Electrode

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Orawon Chailapakul

2008-03-01

Full Text Available A gas diffusion sequential injection system with amperometric detection using aboron-doped diamond electrode was developed for the determination of sulfite. A gasdiffusion unit (GDU was used to prevent interference from sample matrices for theelectrochemical measurement. The sample was mixed with an acid solution to generategaseous sulfur dioxide prior to its passage through the donor channel of the GDU. Thesulfur dioxide diffused through the PTFE hydrophobic membrane into a carrier solution of 0.1 M phosphate buffer (pH 8/0.1% sodium dodecyl sulfate in the acceptor channel of theGDU and turned to sulfite. Then the sulfite was carried to the electrochemical flow cell anddetected directly by amperometry using the boron-doped diamond electrode at 0.95 V(versus Ag/AgCl. Sodium dodecyl sulfate was added to the carrier solution to preventelectrode fouling. This method was applicable in the concentration range of 0.2-20 mgSO32−/L and a detection limit (S/N = 3 of 0.05 mg SO32−/L was achieved. This method wassuccessfully applied to the determination of sulfite in wines and the analytical resultsagreed well with those obtained by iodimetric titration. The relative standard deviations forthe analysis of sulfite in wines were in the range of 1.0-4.1 %. The sampling frequency was65 h−1.

Urinary Sodium and Potassium Excretion and Dietary Sources of Sodium in Maputo, Mozambique

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Ana Queiroz

2017-08-01

Full Text Available This study aimed to evaluate the urinary excretion of sodium and potassium, and to estimate the main food sources of sodium in Maputo dwellers. A cross-sectional evaluation of a sample of 100 hospital workers was conducted between October 2012 and May 2013. Sodium and potassium urinary excretion was assessed in a 24-h urine sample; creatinine excretion was used to exclude unlikely urine values. Food intake in the same period of urine collection was assessed using a 24-h dietary recall. The Food Processor Plus® was used to estimate sodium intake corresponding to naturally occurring sodium and sodium added to processed foods (non-discretionary sodium. Salt added during culinary preparations (discretionary sodium was computed as the difference between urinary sodium excretion and non-discretionary sodium. The mean (standard deviation urinary sodium excretion was 4220 (1830 mg/day, and 92% of the participants were above the World Health Organization (WHO recommendations. Discretionary sodium contributed 60.1% of total dietary sodium intake, followed by sodium from processed foods (29.0% and naturally occurring sodium (10.9%. The mean (standard deviation urinary potassium excretion was 1909 (778 mg/day, and 96% of the participants were below the WHO potassium intake recommendation. The mean (standard deviation sodium to potassium molar ratio was 4.2 (2.4. Interventions to decrease sodium and increase potassium intake are needed in Mozambique.

Assessment of flow induced vibration in a sodium-sodium heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Prakash, V. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India)], E-mail: prakash@igcar.gov.in; Thirumalai, M.; Prabhakar, R.; Vaidyanathan, G. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India)

2009-01-15

The 500 MWe Prototype Fast Breeder Reactor (PFBR) is under construction at Kalpakkam. It is a liquid metal sodium cooled pool type fast reactor with all primary components located inside a sodium pool. The heat produced due to fission in the core is transported by primary sodium to the secondary sodium in a sodium to sodium Intermediate Heat Exchanger (IHX), which in turn is transferred to water in the steam generator. PFBR IHX is a shell and tube type heat exchanger with primary sodium on shell side and secondary sodium in the tube side. Since IHX is one of the critical components placed inside the radioactive primary sodium, trouble-free operation of the IHX is very much essential for power plant availability. To validate the design and the adequacy of the support system provided for the IHX, flow induced vibration (FIV) experiments were carried out in a water test loop on a 60 deg. sector model. This paper discusses the flow induced vibration measurements carried out in 60 deg. sector model of IHX, the modeling criteria, the results and conclusion.

Asymmetric electrochemical supercapacitor, based on polypyrrole coated carbon nanotube electrodes

International Nuclear Information System (INIS)

Su, Y.; Zhitomirsky, I.

2015-01-01

Highlights: • Polypyrrole (PPy) coated multiwalled carbon nanotubes (MWCNT) were prepared. • New method is based on the use of new electrochemically active dopants for PPy. • The dopans provided dispersion of MWCNT and promoted PPy coating formation. • Symmetric PPy–MWCNT supercapacitors showed high capacitance and low resistance. • Asymmetric PPy–MWCNT/VN–MWCNT devices and modules allowed larger voltage window. - Abstract: Conductive polypyrrole (PPy) polymer – multiwalled carbon nanotubes (MWCNT) composites were synthesized using sulfanilic acid azochromotrop (SPADNS) and sulfonazo III sodium salt (CHR-BS) as anionic dopants for chemical polymerization of PPy. The composites were tested for application in electrodes of electrochemical supercapacitors (ES). Sedimentation tests, electrophoretic deposition experiments and Fourier transform infrared spectroscopy (FTIR) investigations showed that strong adsorption of anionic CHR-BS on MWCNT provided MWCNT dispersion. The analysis of scanning and transmission electron microscopy data demonstrated that the use of CHR-BS allowed the formation of PPy coatings on MWCNT. As a result, the composites, prepared using CHR-BS, showed higher capacitance, compared to the composites, prepared using SPADNS. The electrodes, containing MWCNT, coated with PPy showed a capacitance of 179 F g −1 for active mass loading of 10 mg cm −2 , good capacitance retention at scan rates in the range of 2–100 mV s −1 and excellent cyclic stability. Asymmetric ES devices, containing positive PPy–MWCNT electrodes and negative vanadium nitride (VN)–MWCNT electrodes showed significant improvement in energy storage performance, compared to the symmetric ES due to the larger voltage window. The low impedance and high capacitance of the individual cells paved the way to the development of modules with higher voltage, which showed good electrochemical performance

Electrochemical Treatment of Wastewater Containing Mixed Reactive Dyes Using Carbon Nanotube Modified Cathode Electrodes

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Nader Djafarzadeh

2016-11-01

Full Text Available Nowadays, advanced electrochemical oxidation processes are promising methods for the treatment of wastewaters containing organic dyes. One of these methods is the Electro-Fenton (EF technique in which an electrical current is applied to the cathode and anode electrodes to promote electrochemical reactions that generate hydroxyl radicals which mineralize organic pollutants and remove them from wastewater. To carry out the Electro-Fenton process iIn this work, the carbon paper (CP electrode was initially modified with carbon nanotubes (CNT to produce the CP-CNT electrode which was used as the cathode to remove a mixture of organic dyestuff (containing Reactive Blue 69, Reactive Red 195, and Reactive Yellow 84 from wastewaters. Comparison of the two types of cathode electrodes (i.e., CNT and the modified CP-CNT showed that the CP-CNT outperformed the CP electrode. The EF process was employed to treat 500 ml of a mixture of dyes (50 mg/L of each dye containing sodium soulfate and Fe+3 ions. The results revealed that the highest color removal efficiency was achieved when a current of 300 mA was applied for 210 min. COD measurments were used to calculate the effective current and power consumption. It was found that the 300 mA current applied over a period of 210 min yielded the highest effective current and the lowest power consumption. The amount of dyes mineralized by the EF process in the dye solution indicated that 78% of the initial COD had been removed under the above conditions. It may be concluded that the Electro-Fenton process can be successfully used for the treatment of wastewaters containing mixtures of dye pollutants. Cathode electrode type, electrical current, and electrolysis duration were identified as the parameters affecting the process.

Energy harvesting using ionic electro-active polymer thin films with Ag-based electrodes

International Nuclear Information System (INIS)

Anand, S V; Arvind, K; Bharath, P; Roy Mahapatra, D

2010-01-01

In this paper we employ the phenomenon of bending deformation induced transport of cations via the polymer chains in the thickness direction of an electro-active polymer (EAP)–metal composite thin film for mechanical energy harvesting. While EAPs have been applied in the past in actuators and artificial muscles, promising applications of such materials in hydrodynamic and vibratory energy harvesting are reported in this paper. For this, functionalization of EAPs with metal electrodes is the key factor in improving the energy harvesting efficiency. Unlike Pt-based electrodes, Ag-based electrodes have been deposited on an EAP membrane made of Nafion. The developed ionic metal polymer composite (IPMC) membrane is subjected to a dynamic bending load, hydrodynamically, and evaluated for the voltage generated against an external electrical load. An increase of a few orders of magnitude has been observed in the harvested energy density and power density in air, deionized water and in electrolyte solutions with varying concentrations of sodium chloride (NaCl) as compared to Pt-based IPMC performances reported in the published literature. This will have potential applications in hydrodynamic and residual environmental energy harvesting to power sensors and actuators based on micro-and nano-electro-mechanical systems (MEMS and NEMS) for biomedical, aerospace and oceanic applications

Lithium and sodium ion capacitors with high energy and power densities based on carbons from recycled olive pits

Science.gov (United States)

Ajuria, Jon; Redondo, Edurne; Arnaiz, Maria; Mysyk, Roman; Rojo, Teófilo; Goikolea, Eider

2017-08-01

In this work, we are presenting both lithium and sodium ion capacitors (LIC and NIC) entirely based on electrodes designed from recycled olive pit bio-waste derived carbon materials. On the one hand, olive pits were pyrolized to obtain a low specific surface area semigraphitic hard carbon to be used as the ion intercalation (battery-type) negative electrode. On the other hand, the same hard carbon was chemically activated with KOH to obtain a high specific surface area activated carbon that was further used as the ion-adsorption (capacitor-type) positive electrode. Both electrodes were custom-made to be assembled in a hybrid cell to either build a LIC or NIC in the corresponding Li- and Na-based electrolytes. For comparison purposes, a symmetric EDLC supercapacitor cell using the same activated carbon in 1.5 M Et4NBF4/acetonitrile electrolyte was also built. Both LIC and NIC systems demonstrate remarkable energy and power density enhancement over its EDLC counterpart while showing good cycle life. This breakthrough offers the possibility to easily fabricate versatile hybrid ion capacitors, covering a wide variety of applications where different requirements are demanded.

Sodium vapor deposition onto a horizontal flat plate above liquid sodium surface, (3)

International Nuclear Information System (INIS)

Kudo, Kazuhiko; Hirata, Masaru.

1978-01-01

Sodium vapour and sodium mist in the cover gas of a sodium system of a fast breeder reactor cause various problems. In this report, with the results of measurements of sodium mist concentration, the distribution of sodium mist diameter in cover gas was analytically obtained. The analysis was made by using the different nucleus model B. The measurement of the concentration of sodium mist was carried out with a sodium mist pot designed by the author. The experiment was done at the sodium temperature of 400 and 500 degree centigrade. The relations among sodium temperature, upper wall temperature, and the sodium mist concentration in cover gas were obtained. Evaluation of effective condensed nuclear radius in the cover gas was made by the comparison of analysis and experimental results. The results of this evaluation shows the following conclusions. It is impossible to express the distribution of sodium mist diameter by normal distribution or logarithmic normal distribution. Drop of sodium temperature results in the decrease of weight mean radius of generated sodium mist. Drop of upper wall temperature causes the decrease of weight mean radius, and increases sodium mist concentration. (Kato, T.)

An investigation of sodium iodide solubility in sodium-stainless steel systems

International Nuclear Information System (INIS)

Sagawa, Norihiko; Tashiro, Suguru

1996-01-01

Sodium iodide and major constituents of stainless steel in sodium are determined by using the steel capsules to obtain a better understanding on contribution of the constituents to the apparent iodide solubility in sodium. The capsule loaded with 20 g sodium and 0.1 - 0.3 g powder of sodium iodide is heated at its upper part in a furnace and cooled at its bottom on brass plates to establish a large temperature gradient along the capsule tube. After a given period of equilibration, the iodide and constituents are fixed in solidified sodium by quick quenching of the capsules. Sodium samples are taken from the sectioned capsule tube and submitted to sodium dissolution by vaporized water for determination of the iodine and to vacuum distillation for determination of the metal elements. Iron and nickel concentrations are observed to be lower in the samples at higher iodine concentrations. Chromium and manganese concentrations are seen to be insensitive to the iodine concentrations. The observations can be interpreted by a model that sodium oxide combines with metal iodide in sodium to form a complex compound and with consideration that the compound will fall and deposit onto the bottom of the capsule by thermal diffusion. (author)

Influence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) on zinc electrodeposition

International Nuclear Information System (INIS)

Lehr, I.L.; Saidman, S.B.

2012-01-01

This work is a study of the electrodeposition of zinc onto SAE 4140 steel electrodes using solutions containing zinc sulfate and bis(2-ethylhexyl) sodium sulfosuccinate (AOT). The influence of different parameters such as electrolyte concentration, electrodeposition time and temperature on the morphology of the electrodeposits was analyzed. The deposits were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction. The variation of open circuit potential over time in chloride solutions was also evaluated. The nucleation-growth process and consequently the morphology of the electrodeposits are modified in the presence of AOT. The surfactant induces the formation of a porous deposit.

Influence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) on zinc electrodeposition

Science.gov (United States)

Lehr, I. L.; Saidman, S. B.

2012-03-01

This work is a study of the electrodeposition of zinc onto SAE 4140 steel electrodes using solutions containing zinc sulfate and bis(2-ethylhexyl) sodium sulfosuccinate (AOT). The influence of different parameters such as electrolyte concentration, electrodeposition time and temperature on the morphology of the electrodeposits was analyzed. The deposits were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction. The variation of open circuit potential over time in chloride solutions was also evaluated. The nucleation-growth process and consequently the morphology of the electrodeposits are modified in the presence of AOT. The surfactant induces the formation of a porous deposit.

49 CFR 173.189 - Batteries containing sodium or cells containing sodium.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Batteries containing sodium or cells containing sodium. 173.189 Section 173.189 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.189 Batteries containing sodium or cells containing sodium. (a...

Cavitation erosion in sodium flow, sodium cavitation tunnel testing

International Nuclear Information System (INIS)

Courbiere, Pierre.

1981-04-01

The high-volume sodium flows present in fast neutron reactors are liable to induce cavitation phenomena in various portion of the sodium lines and pumps. The absence of sufficient data in this area led the C.E.A. to undertake an erosion research program in cavitating sodium flow. This paper discusses the considerations leading to the definition and execution of sodium cavitation erosion tests, and reviews the tests run with 400 0 C sodium on various steel grades: 316, 316 L, 316 Ti (Z8CNDT17-12), Poral (Z3CND18-12), 304 L and LN2 - clad 316 L (Ni coating-clad 316 L). Acoustic detection and signal processing methods were used with an instrument package designed and implemented at the Cadarache Nuclear Research Center

Removal of sodium from the component of the sodium purification loop

International Nuclear Information System (INIS)

Kim, Byung Ho; Jeong, Kyung Chai; Jeong, Ji Young; Kim, Jong Man; Choi, Byung Hae; Nam, Ho Yun

2005-01-01

The purpose of a cleaning process is to remove the residual sodium adhering to the component walls once it has been properly drained. It is necessary to clean and decontaminate a component, especially the large components of the primary coolant system; such as the intermediate heat exchangers and the primary pump. Improper and inadequate cleaning has in a number of cases resulted in problems in the storage, handling, and reuse of components. Several types of failures due to improper cleaning procedures have been defined in the past. Inadequate and incomplete removal of sodium results in residues which may contain metallic sodium and alkaline compounds such as sodium hydroxide, sodium oxide, sodium carbonate, and various types of alcoholates. Reinsertion of components containing these compounds into a high-temperature sodium system can result in either the intergranular penetration characteristic of a high-oxygen sodium or an accelerated corrosion due to oxygen. The methods used for cleaning sodium equipment depend on the condition and types of equipment to be cleaned and whether the equipment is to be reused. Cleaning methods are needed that will avoid a deleterious local overheating, material surface degradation or deposits, chemical, physical, or mechanical damage, and external effects. This paper discusses a steam-nitrogen gas cleaning method for the routine applications that permits the reuse of the cold trap in sodium

Electrochemical synthesis and characterization of stable colloidal suspension of graphene using two-electrode cell system

Energy Technology Data Exchange (ETDEWEB)

Danial, Wan Hazman, E-mail: hazmandanial@gmail.com; Majid, Zaiton Abdul, E-mail: zaiton@kimia.fs.utm.my; Aziz, Madzlan [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor (Malaysia); Chutia, Arunabhiram [Institute of Fluid Sciences, Tohoku University, Sendai 980-8577 (Japan); Sahnoun, Riadh [Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor (Malaysia)

2015-07-22

The present work reports the synthesis and characterization of graphene via electrochemical exfoliation of graphite rod using two-electrode system assisted by Sodium Dodecyl Sulphate (SDS) as a surfactant. The electrochemical process was carried out with sequence of intercalation of SDS onto the graphite anode followed by exfoliation of the SDS-intercalated graphite electrode when the anode was treated as cathode. The effect of intercalation potential from 5 V to 9 V and concentration of the SDS surfactant of 0.1 M and 0.01 M were investigated. UV-vis Spectroscopic analysis indicated an increase in the graphene production with higher intercalation potential. Transmission Electron Microscopy (TEM) analysis showed a well-ordered hexagonal lattice of graphene image and indicated an angle of 60° between two zigzag directions within the honeycomb crystal lattice. Raman spectroscopy analysis shows the graphitic information effects after the exfoliation process.

Solvation behavior of carbonate-based electrolytes in sodium ion batteries.

Science.gov (United States)

Cresce, Arthur V; Russell, Selena M; Borodin, Oleg; Allen, Joshua A; Schroeder, Marshall A; Dai, Michael; Peng, Jing; Gobet, Mallory P; Greenbaum, Steven G; Rogers, Reginald E; Xu, Kang

2016-12-21

Sodium ion batteries are on the cusp of being a commercially available technology. Compared to lithium ion batteries, sodium ion batteries can potentially offer an attractive dollar-per-kilowatt-hour value, though at the penalty of reduced energy density. As a materials system, sodium ion batteries present a unique opportunity to apply lessons learned in the study of electrolytes for lithium ion batteries; specifically, the behavior of the sodium ion in an organic carbonate solution and the relationship of ion solvation with electrode surface passivation. In this work the Li + and Na + -based solvates were characterized using electrospray mass spectrometry, infrared and Raman spectroscopy, 17 O, 23 Na and pulse field gradient double-stimulated-echo pulse sequence nuclear magnetic resonance (NMR), and conductivity measurements. Spectroscopic evidence demonstrate that the Li + and Na + cations share a number of similar ion-solvent interaction trends, such as a preference in the gas and liquid phase for a solvation shell rich in cyclic carbonates over linear carbonates and fluorinated carbonates. However, quite different IR spectra due to the PF 6 - anion interactions with the Na + and Li + cations were observed and were rationalized with the help of density functional theory (DFT) calculations that were also used to examine the relative free energies of solvates using cluster - continuum models. Ion-solvent distances for Na + were longer than Li + , and Na + had a greater tendency towards forming contact pairs compared to Li + in linear carbonate solvents. In tests of hard carbon Na-ion batteries, performance was not well correlated to Na + solvent preference, leading to the possibility that Na + solvent preference may play a reduced role in the passivation of anode surfaces and overall Na-ion battery performance.

Ultra-low cost and highly stable hydrated FePO4 anodes for aqueous sodium-ion battery

Science.gov (United States)

Wang, Yuesheng; Feng, Zimin; Laul, Dharminder; Zhu, Wen; Provencher, Manon; Trudeau, Michel L.; Guerfi, Abdelbast; Zaghib, Karim

2018-01-01

The growing demands for large-scale energy storage devices have put a spotlight on aqueous sodium-ion batteries, which possess a number of highly desirable features, such as sodium abundance, low cost and safety over organic electrolytes. While lots of cathode materials were reported, only few candidate materials like active carbon and NaTi2(PO4)3 were proposed as anodes. It is a long-standing common knowledge that the low cost, non-toxicity, and highly reversible FePO4·2H2O is known as an attractive cathode material for non-aqueous lithium- and sodium-ion batteries, but we demonstrate for the first time that nano-size non-carbon coated amorphous FePO4·2H2O can be used as the anode for an aqueous sodium-ion battery. Its optimum operating voltage (∼2.75 V vs. Na+/Na) avoids hydrogen evolution. The capacity is as high as 80 mAh/g at a rate of 0.5 C in a three-electrode system. The full cell, using the Na0.44MnO2 as cathode, maintained 90% of the capacity at 300 cycles at a rate of 3 C. The calculations also show that its volume change during the intercalation of Na ions is below 2%. Its low cost, high safety, along with its outstanding electrochemical performance makes amorphous FePO4·2H2O a promising anode material for aqueous sodium-ion batteries.

Design, fabrication and skin-electrode contact analysis of polymer microneedle-based ECG electrodes

Science.gov (United States)

O'Mahony, Conor; Grygoryev, Konstantin; Ciarlone, Antonio; Giannoni, Giuseppe; Kenthao, Anan; Galvin, Paul

2016-08-01

Microneedle-based ‘dry’ electrodes have immense potential for use in diagnostic procedures such as electrocardiography (ECG) analysis, as they eliminate several of the drawbacks associated with the conventional ‘wet’ electrodes currently used for physiological signal recording. To be commercially successful in such a competitive market, it is essential that dry electrodes are manufacturable in high volumes and at low cost. In addition, the topographical nature of these emerging devices means that electrode performance is likely to be highly dependent on the quality of the skin-electrode contact. This paper presents a low-cost, wafer-level micromoulding technology for the fabrication of polymeric ECG electrodes that use microneedle structures to make a direct electrical contact to the body. The double-sided moulding process can be used to eliminate post-process via creation and wafer dicing steps. In addition, measurement techniques have been developed to characterize the skin-electrode contact force. We perform the first analysis of signal-to-noise ratio dependency on contact force, and show that although microneedle-based electrodes can outperform conventional gel electrodes, the quality of ECG recordings is significantly dependent on temporal and mechanical aspects of the skin-electrode interface.

Design, fabrication and skin-electrode contact analysis of polymer microneedle-based ECG electrodes

International Nuclear Information System (INIS)

O’Mahony, Conor; Grygoryev, Konstantin; Ciarlone, Antonio; Giannoni, Giuseppe; Kenthao, Anan; Galvin, Paul

2016-01-01

Microneedle-based ‘dry’ electrodes have immense potential for use in diagnostic procedures such as electrocardiography (ECG) analysis, as they eliminate several of the drawbacks associated with the conventional ‘wet’ electrodes currently used for physiological signal recording. To be commercially successful in such a competitive market, it is essential that dry electrodes are manufacturable in high volumes and at low cost. In addition, the topographical nature of these emerging devices means that electrode performance is likely to be highly dependent on the quality of the skin-electrode contact.This paper presents a low-cost, wafer-level micromoulding technology for the fabrication of polymeric ECG electrodes that use microneedle structures to make a direct electrical contact to the body. The double-sided moulding process can be used to eliminate post-process via creation and wafer dicing steps. In addition, measurement techniques have been developed to characterize the skin-electrode contact force. We perform the first analysis of signal-to-noise ratio dependency on contact force, and show that although microneedle-based electrodes can outperform conventional gel electrodes, the quality of ECG recordings is significantly dependent on temporal and mechanical aspects of the skin-electrode interface. (paper)

Effect of sodium lactate /sodium diacetate in combination with sodium nitrite on physiochemical, microbial properties and sensory evaluation of cow sausage

Directory of Open Access Journals (Sweden)

Habib Sedghi

2014-11-01

Full Text Available Sodium nitrite has been always considered as one of the common additives due to its antibacterial effects on Clostridium botulinum and meat products' color, however it produces cancer creating nitrosamine. Recently, organic acids and their salts such as lactates have been employed as antimicrobial compounds. Lactates also improve organileptic properties including color, texture and taste and antioxidant properties. Sodium lactate causes to more reduction of anaerobic spore former bacteria than nitrite, inhibits botulin produced by Clostridium botulinum. Sodium lactate produces a permanent reddish pink color through reduction of deoxymygloboline and producing deoxymyoglobuline. In this study, the decrease of sodium nitrite amount from 120ppm to 15ppm by adding sodium lactate / sodium diacetate led to achieve an acceptable product. The best results revealed through adding 3.0625% of sodium lactate / sodium diacetate in combination with 30ppm sodium nitrite. Results also exhibited more reduction of pathogens' growth than nitrite, enhanced flavor slightly, but unable to produce reddish pink color as produced by nitrite. Results also exhibited that sodium lactate / diacetate cause to retard in microbial growth, reducing chemical change, enhance sensory properties, partially improvement in taste and texture. Although inappropriate color demonstrated sodium lactate / diacetate's inability in red pink color production in 4th sample (contains 15 ppm nitrite, its synergy effect in combination with sodium nitrite on nitroso myoglobuline production has been proven, led to sodium nitrite reduction in sausages.

Electrolytic process to produce sodium hypochlorite using sodium ion conductive ceramic membranes

Science.gov (United States)

Balagopal, Shekar; Malhotra, Vinod; Pendleton, Justin; Reid, Kathy Jo

2012-09-18

An electrochemical process for the production of sodium hypochlorite is disclosed. The process may potentially be used to produce sodium hypochlorite from seawater or low purity un-softened or NaCl-based salt solutions. The process utilizes a sodium ion conductive ceramic membrane, such as membranes based on NASICON-type materials, in an electrolytic cell. In the process, water is reduced at a cathode to form hydroxyl ions and hydrogen gas. Chloride ions from a sodium chloride solution are oxidized in the anolyte compartment to produce chlorine gas which reacts with water to produce hypochlorous and hydrochloric acid. Sodium ions are transported from the anolyte compartment to the catholyte compartment across the sodium ion conductive ceramic membrane. Sodium hydroxide is transported from the catholyte compartment to the anolyte compartment to produce sodium hypochlorite within the anolyte compartment.

High performance cermet electrodes

Science.gov (United States)

Isenberg, Arnold O.; Zymboly, Gregory E.

1986-01-01

Disclosed is a method of increasing the operating cell voltage of a solid oxide electrochemical cell having metal electrode particles in contact with an oxygen-transporting ceramic electrolyte. The metal electrode is heated with the cell, and oxygen is passed through the oxygen-transporting ceramic electrolyte to the surface of the metal electrode particles so that the metal electrode particles are oxidized to form a metal oxide layer between the metal electrode particles and the electrolyte. The metal oxide layer is then reduced to form porous metal between the metal electrode particles and the ceramic electrolyte.

Anthraquinone derivative as high-performance anode material for sodium-ion batteries using ether-based electrolytes

Directory of Open Access Journals (Sweden)

Linqin Mu

2018-01-01

Full Text Available Organic materials, especially the carbonyl compounds, are promising anode materials for room temperature sodium-ion batteries owing to their high reversible capacity, structural diversity as well as eco-friendly synthesis from bio-mass. Herein, we report a novel anthraquinone derivative, C14H6O4Na2 composited with carbon nanotube (C14H6O4Na2-CNT, used as an anode material for sodium-ion batteries in ether-based electrolyte. The C14H6O4Na2-CNT electrode delivers a reversible capacity of 173 mAh g−1 and an ultra-high initial Coulombic efficiency of 98% at the rate of 0.1 C. The capacity retention is 82% after 50 cycles at 0.2 C and a good rate capability is displayed at 2 C. Furthermore, the average Na insertion voltage of 1.27 V vs. Na+/Na makes it a unique and safety battery material, which would avoid Na plating and formation of solid electrolyte interface. Our contribution provides new insights for designing developed organic anode materials with high initial Coulombic efficiency and improved safety capability for sodium-ion batteries.

Building better lithium-sulfur batteries: from LiNO3 to solid oxide catalyst

Science.gov (United States)

Ding, Ning; Zhou, Lan; Zhou, Changwei; Geng, Dongsheng; Yang, Jin; Chien, Sheau Wei; Liu, Zhaolin; Ng, Man-Fai; Yu, Aishui; Hor, T. S. Andy; Sullivan, Michael B.; Zong, Yun

2016-09-01

Lithium nitrate (LiNO3) is known as an important electrolyte additive in lithium-sulfur (Li-S) batteries. The prevailing understanding is that LiNO3 reacts with metallic lithium anode to form a passivation layer which suppresses redox shuttles of lithium polysulfides, enabling good rechargeability of Li-S batteries. However, this view is seeing more challenges in the recent studies, and above all, the inability of inhibiting polysulfide reduction on Li anode. A closely related issue is the progressive reduction of LiNO3 on Li anode which elevates internal resistance of the cell and compromises its cycling stability. Herein, we systematically investigated the function of LiNO3 in redox-shuttle suppression, and propose the suppression as a result of catalyzed oxidation of polysulfides to sulfur by nitrate anions on or in the proximity of the electrode surface upon cell charging. This hypothesis is supported by both density functional theory calculations and the nitrate anions-suppressed self-discharge rate in Li-S cells. The catalytic mechanism is further validated by the use of ruthenium oxide (RuO2, a good oxygen evolution catalyst) on cathode, which equips the LiNO3-free cell with higher capacity and improved capacity retention over 400 cycles.

Effect of Anion on Behaviour of Li-S Battery Electrolyte Solutions Based on N-Methyl-N-Butyl-Pyrrolidinium Ionic Liquids

International Nuclear Information System (INIS)

Barghamadi, Marzieh; Best, Adam S.; Bhatt, Anand I.; Hollenkamp, Anthony F.; Mahon, Peter J.; Musameh, Mustafa; Rüther, Thomas

2015-01-01

The electrochemical behaviour and electrical performance are investigated for a series of lithium-sulfur (Li-S) cells in which the electrolyte solutions are organic solvent-ionic liquid mixtures that are based on the 1-butyl-1-methylpyrrolidinium (C 4 mpyr) cation with a range of anions. In each case, performance is compared with cells that are based on a standard mixed-ether organic electrolyte. The capacity of cells assembled with electrolytes containing 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate (C 4 mpyr-FAP), 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate (C 4 mpyr-OTf), or 1-butyl-1-methylpyrrolidinium tricyanomethanide (C 4 mpyr-TCM) decline rapidly due to low conductivity, high polysulfide solubility and side reaction of electrolyte with electrodes, respectively. Our results confirm that polysulfide solubility is strongly controlled by the anion of the ionic liquid and verify that not all ionic liquids decrease polysulfide solubility. In agreement with previous reports, 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (C 4 mpyr-TFSI) shows the best compatibility in Li-S batteries and has a higher coulombic efficiency of greater than 99% over 100 cycles. Furthermore, impedance spectroscopy confirms that electrolyte composition influences the SEI layer formed on the lithium anode and its subsequent impedance.

A new rechargeable sodium battery utilizing reversible topotactic oxygen extraction/insertion of CaFeO(z) (2.5 ≤ z ≤ 3) in an organic electrolyte.

Science.gov (United States)

Hibino, Mitsuhiro; Harimoto, Ryuji; Ogasawara, Yoshiyuki; Kido, Ryota; Sugahara, Akira; Kudo, Tetsuichi; Tochigi, Eita; Shibata, Naoya; Ikuhara, Yuichi; Mizuno, Noritaka

2014-01-08

At present, significant research efforts are being devoted both to identifying means of upgrading existing batteries, including lithium ion types, and also to developing alternate technologies, such as sodium ion, metal-air, and lithium-sulfur batteries. In addition, new battery systems incorporating novel electrode reactions are being identified. One such system utilizes the reaction of electrolyte ions with oxygen atoms reversibly extracted and reinserted topotactically from cathode materials. Batteries based on this system allow the use of various anode materials, such as lithium and sodium, without the requirement to develop new cathode intercalation materials. In the present study, this concept is employed and a new battery based on a CaFeO3 cathode with a sodium anode is demonstrated.

Potentiometric Determination of Ketotifen Fumarate in Pharmaceutical Preparations and Urine Using Carbon Paste and PVC Membrane Selective Electrodes

Directory of Open Access Journals (Sweden)

Eman Y. Z. Frag

2011-01-01

Full Text Available This study compares between unmodified carbon paste (CPE; the paste has no ion pair and polyvinyl chloride (PVC membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF, where sodium tetraphenylborate (NaTPB was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10−7 to 10−2 mol L−1. The electrodes show Nernstian slope value of 52.51±0.20 and 51.51±0.25 mV decade−1 for CPE and PVC membrane electrodes at 30∘C, respectively. The potential is nearly stable over the pH range 3.0–6.0 and 2.0–7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets, and biological fluid (urine. The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97±0.53 and 98.62±0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.

Potentiometric determination of ketotifen fumarate in pharmaceutical preparations and urine using carbon paste and PVC membrane selective electrodes.

Science.gov (United States)

Frag, Eman Y Z; Mohamed, Gehad G; Khalil, Mohamed M; Hwehy, Mohammad M A

2011-01-01

This study compares between unmodified carbon paste (CPE; the paste has no ion pair) and polyvinyl chloride (PVC) membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF), where sodium tetraphenylborate (NaTPB) was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10(-7) to 10(-2) mol L(-1). The electrodes show Nernstian slope value of 52.51 ± 0.20 and 51.51 ± 0.25 mV decade(-1) for CPE and PVC membrane electrodes at 30°C, respectively. The potential is nearly stable over the pH range 3.0-6.0 and 2.0-7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets), and biological fluid (urine). The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97 ± 0.53 and 98.62 ± 0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.

Report of sodium cavitation

International Nuclear Information System (INIS)

Murai, Hitoshi; Shima, Akira; Oba, Toshisaburo; Kobayashi, Ryoji; Hashimoto, Hiroyuki

1975-01-01

The damage of components for LMFBRs due to sodium cavitation is serious problem. This report summarizes the following items, (1) mechanism of the incipience of sodium cavitation, (2) damage due to sodium cavitation, (3) detection method for sodium cavitation, and (4) estimation method for sodium cavitation by the comparison with water cavitation. Materials were collected from the reports on liquid metal cavitation, sodium cavitation and water cavitation published from 1965 to now. The mechanism of the incipience of sodium cavitation cavitation parameters (mean location, distributed amount or occurrence aspect and stability), experiment of causing cavitation with Venturi tube, and growth of bubbles within superheated sodium. The sodium cavitation damage was caused by magnetostriction vibration method and with Venturi tube. The state of damage was investigated with the cavitation performance of a sodium pump, and the damage was examined in view of the safety of LMFBR plants. Sodium cavitation was detected with acoustic method, radiation method, and electric method. The effect of physical property of liquid on incipient cavitation was studied. These are thermodynamic effect based on quasistatic thermal equilibrium condition and the effect of the physical property of liquid based on bubble dynamics. (Iwase, T.)

Liquid electrode

Science.gov (United States)

Ekechukwu, A.A.

1994-07-05

A dropping electrolyte electrode is described for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions. 2 figures.

Total-body sodium and sodium excess

International Nuclear Information System (INIS)

Aloia, J.F.; Cohn, S.H.; Abesamis, C.; Babu, T.; Zanzi, I.; Ellis, K.

1980-01-01

Total-body levels of sodium (TBNa), chlorine (TBCI), calcium (TBCa), and potassium (TBK) were measured by neutron activation and analysis of results by whole body counting in 66 postmenopausal women. The relationship between TBNa, and TBCl, TBK, and TBCa on the one hand, and height and weight on the other, were found to compare with those previously reported. The hypothesis that TBNa and TBCl are distributed normally could not be rejected. The sodium excess (Na/sub es/) is defined as the sodium that is present in excess of that associated with the extracellular fluid (chlorine) space; the Na/sub es/ approximates nonexchangeable bone sodium. In these 66 postmenopausal women, and in patients with different endocrinopathies previously described, the values on Na/sub es/ did not differ from the normal values except in the thyrotoxicosis patients, where they were decreased. A close relationship between Na/sub es/ and TBCa was maintained in the endocrinopathies studied. This relationship was found in conditions accompanied by either an increment or a loss of skeletal mass. It appears that the NA/sub es/ value is primarily dependent upon the calcium content of bone

Electrochemical oxidation of dihydronicotinamide adenine dinucleotide at nitrogen-doped carbon nanotube electrodes.

Science.gov (United States)

Goran, Jacob M; Favela, Carlos A; Stevenson, Keith J

2013-10-01

Nitrogen-doped carbon nanotubes (N-CNTs) substantially lower the overpotential necessary for dihydronicotinamide adenine dinucleotide (NADH) oxidation compared to nondoped CNTs or traditional carbon electrodes such as glassy carbon (GC). We observe a 370 mV shift in the peak potential (Ep) from GC to CNTs and another 170 mV shift from CNTs to 7.4 atom % N-CNTs in a sodium phosphate buffer solution (pH 7.0) with 2.0 mM NADH (scan rate 10 mV/s). The sensitivity of 7.4 atom % N-CNTs to NADH was measured at 0.30 ± 0.04 A M(-1) cm(-2), with a limit of detection at 1.1 ± 0.3 μM and a linear range of 70 ± 10 μM poised at a low potential of -0.32 V (vs Hg/Hg2SO4). NADH fouling, known to occur to the electrode surface during NADH oxidation, was investigated by measuring both the change in Ep and the resulting loss of electrode sensitivity. NADH degradation, known to occur in phosphate buffer, was characterized by absorbance at 340 nm and correlated with the loss of NADH electroactivity. N-CNTs are further demonstrated to be an effective platform for dehydrogenase-based biosensing by allowing glucose dehydrogenase to spontaneously adsorb onto the N-CNT surface and measuring the resulting electrode's sensitivity to glucose. The glucose biosensor had a sensitivity of 0.032 ± 0.003 A M(-1) cm(-2), a limit of detection at 6 ± 1 μM, and a linear range of 440 ± 50 μM.

Design of hierarchical CuS/graphene architectures with enhanced lithium storage capability

Energy Technology Data Exchange (ETDEWEB)

Ding, Caihua; Su, Dezhi [Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081 (China); Ma, Wenxian [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Zhao, Yongjie, E-mail: zhaoyjpeace@gmail.com [Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081 (China); Yan, Dong [Department of Mechanical Engineering, Tsinghua University, Beijing, 100084 (China); State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084 (China); Li, Jingbo; Jin, Haibo [Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081 (China)

2017-05-01

Highlights: • A delicate route was proposed for rational design of CuS/graphene composite. • Hierarchical CuS was composed of large amounts of well-arranged nanosheets. • The rationally designed structure of composite offered stable-hosts for Li{sup +} insertion. • The graphene constructed conductive paths and a network for fast transport of Li{sup +}. • The presence of the graphene in the composite reduced the dissolution of polysulfides. - Abstract: Metal-sulfides electrode materials usually suffer from poor cyclability and low rate capability in rechargeable batteries as a result of the pulverization of active materials and the loss of sulfur material induced by polysulfide dissolution. Herein, we reported a delicate and scalable route for rational design of CuS/graphene composites. Hierarchical CuS microparticles comprising of large amounts of self-assembled and well-arranged nanosheets uniformly mixed with flexible graphene layers. The obtained CuS/graphene electrodes exhibited high specific capacities, excellent cycling stability and desirable rate capability when being evaluated as anode materials for lithium-ion batteries. The high specific capacities of 568 mA h g{sup −1} after 100 cycles at 50 mA g{sup −1} and 143 mA h g{sup −1} at 1000 mA g{sup −1} (in rate testing) were achieved, suggesting a very promising candidate for high-performance lithium-ion batteries. The rationally designed structures of the CuS/graphene composites offered stable-hosts for Li{sup +} insertion and alleviated the volume changes upon cycling. The presence of the graphene in composite not only constructed conductive paths and a network for fast transport of Li{sup +}, but also effectively reduced the dissolution of polysulfides into electrolyte. This graphene-based composite with hierarchical structure could be used as a safe, low-cost, and versatile material for extensively potential applications.

Design of hierarchical CuS/graphene architectures with enhanced lithium storage capability

International Nuclear Information System (INIS)

Ding, Caihua; Su, Dezhi; Ma, Wenxian; Zhao, Yongjie; Yan, Dong; Li, Jingbo; Jin, Haibo

2017-01-01

Highlights: • A delicate route was proposed for rational design of CuS/graphene composite. • Hierarchical CuS was composed of large amounts of well-arranged nanosheets. • The rationally designed structure of composite offered stable-hosts for Li + insertion. • The graphene constructed conductive paths and a network for fast transport of Li + . • The presence of the graphene in the composite reduced the dissolution of polysulfides. - Abstract: Metal-sulfides electrode materials usually suffer from poor cyclability and low rate capability in rechargeable batteries as a result of the pulverization of active materials and the loss of sulfur material induced by polysulfide dissolution. Herein, we reported a delicate and scalable route for rational design of CuS/graphene composites. Hierarchical CuS microparticles comprising of large amounts of self-assembled and well-arranged nanosheets uniformly mixed with flexible graphene layers. The obtained CuS/graphene electrodes exhibited high specific capacities, excellent cycling stability and desirable rate capability when being evaluated as anode materials for lithium-ion batteries. The high specific capacities of 568 mA h g −1 after 100 cycles at 50 mA g −1 and 143 mA h g −1 at 1000 mA g −1 (in rate testing) were achieved, suggesting a very promising candidate for high-performance lithium-ion batteries. The rationally designed structures of the CuS/graphene composites offered stable-hosts for Li + insertion and alleviated the volume changes upon cycling. The presence of the graphene in composite not only constructed conductive paths and a network for fast transport of Li + , but also effectively reduced the dissolution of polysulfides into electrolyte. This graphene-based composite with hierarchical structure could be used as a safe, low-cost, and versatile material for extensively potential applications.

Sodium fluxes in sweet pepper exposed to varying sodium concentrations

NARCIS (Netherlands)

Blom-Zandstra, M.; Vogelzang, S.A.; Veen, B.W.

1998-01-01

The sodium transport and distribution of sweet pepper (Capsicum annuum L.) under saline conditions were studied after transferring the plants to a sodium-free nutrient solution. Sodium stress up to 60 mM did not affect the growth of sweet pepper, as it appears able to counteract the unfavourable

Reaction velocity of sodium hydration in humid air and sodium carbonation in humid carbon dioxide atmosphere. Fundamental study on sodium carbonate process in FBR bulk sodium coolant disposal technology

International Nuclear Information System (INIS)

Tadokoro, Yutaka; Yoshida, Eiichi

1999-11-01

A sodium carbonate processing method, which changes sodium to sodium carbonate and/or sodium bicarbonate by humid carbon dioxide, has been examined and about to be applied to large test loops dismantling. However, that the basic data regarding the progress of the reaction is insufficient on the other hand, is a present condition. The present report therefore aims at presenting basic data regarding the reaction velocity of sodium hydration in humid air and sodium carbonation in humid carbon dioxide atmosphere, and observing the reaction progress, for the application to large test loops dismantling. The test result is summarized as follows. (1) Although the reaction velocity of sodium varied with sodium specimen sizes and velocity measurement methods, the reaction velocity of sodium hydration was in about 0.16 ∼ 0.34 mmh -1 (0.016 ∼ 0.033g cm -2 h -1 , 6.8x10 -4 ∼ 1.4x10 -3 mol cm -2 h -1 ) and that of sodium carbonation was in about 0.16 ∼ 0.27mmh -1 (0.016 ∼ 0.023g cm -2 h -1 , 6.8x10 -4 ∼ 1.1x10 -3 mol cm -2 h -1 ) (26 ∼ 31degC, RH 100%). (2) The reaction velocity of sodium in carbon dioxide atmosphere was greatly affected by vapor partial pressure (absolutely humidity). And the velocity was estimated in 0.08 ∼ 0.12mmh -1 (0.008 ∼ 0.012g cm -2 h -1 , 3.4x10 -4 ∼ 5.2x10 -4 mol cm -2 h -1 ) in the carbon dioxide atmosphere, whose temperature of 20degC and relative humidity of 80% are assumed real sodium carbonate process condition. (3) By the X-ray diffraction method, NaOH was found in humid air reaction product. Na 2 CO 3 , NaHCO 3 were found in carbon dioxide atmosphere reaction product. It was considered that Sodium changes to NaOH, and subsequently to NaHCO 3 through Na 2 CO 3 . (4) For the application to large test loops dismantling, it is considered possible to change sodium to a target amount of sodium carbonate (or sodium bicarbonate) by setting up gas supply quantity and also processing time appropriately according to the surface area

Zinc deposition and dissolution in methanesulfonic acid onto a carbon composite electrode as the negative electrode reactions in a hybrid redox flow battery

International Nuclear Information System (INIS)

Leung, P.K.; Ponce-de-Leon, C.; Low, C.T.J.; Walsh, F.C.

2011-01-01

Highlights: → Use methanesulfonic acid to avoid dendrite formation during a long (>4 h) zinc electrodeposition. → Electrochemical characterization of Zn(II) deposition and its morphology using methanesulfonic acid solutions. → Use of additives to improve the efficiency of zinc deposition and dissolution as the half cell reaction of a redox flow battery. - Abstract: Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn 2+ ions was 7.5 x 10 -6 cm 2 s -1 . The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn 2+ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2 x 10 -3 mol dm -3 of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4 h at 50 mA cm -2 .

Sodium intake and dietary sources of sodium in undergraduate students from Novi Sad, Serbia

Directory of Open Access Journals (Sweden)

Jovičić-Bata Jelena

2016-01-01

Full Text Available Background/Aim. Data on sodium intake and sources of sodium in the diet in Serbia are limited. The aim of this study was to estimate the sodium intake and identify the sources of sodium in the diet of undergraduate students attending the University of Novi Sad. Methods. Students completed a questionnaire to gather data on their gender, age and university faculty attended, and then a 24 h dietary recall. The sodium intake of the students was calculated using the dietary recall data and data on the sodium content of foods. The contribution of different food groups as well as of specific foodstuffs to the total sodium intake was calculated. Results. The mean estimated sodium intake of the students was 3,938.5 ± 1,708.1 mg/day. The sodium intake of 89.1% of the surveyed students exceeded the guideline for sodium intake, the majority of the sodium coming from processed foods (78.9% of the total sodium intake. The food groups that contributed the most to the total sodium intake of the students were meat and meat products (21.7% and cereals and cereal-based products (18.6%. Bread and other bakery products were responsible for 13.1% of the total sodium intake. Conclusion. High sodium intake in students of the University of Novi Sad puts them at high risk of developing high blood pressure. The food industry should work towards reformulating products with high sodium content, especially bread and other bakery products. Efforts should be taken to reduce sodium intake among undergraduate students in Novi Sad.

The impedance of anodic pro-cesses on passive NiSi-electrode in sulfuric fluoride containing electrolyte

Directory of Open Access Journals (Sweden)

V. V. Panteleeva

2016-03-01

Full Text Available The mechanism and kinetics of anodic oxidation of the Ni-Si electrode in solutions of 0.5 M H2SO4 + (0,005 – 0,05M NaF in the passive state were investigated by methods of polarization and impedance measurements.Theimpedance spectra are interpreted on the assumption about the formation of the bilayer oxide film on the surface of the silicide nickel, the outer layer which has a porous structure.The growth of the porous layer with the increase of the electrode potential in the investigated solutions is linearly (constant anodizing is 2.2 nm/V.The increase in NaF concentration leads to a decrease in the thickness of the porous layer. The growth of the barrier layer of the oxide film was described in the framework of the model of point defects.The diffusion coefficient of oxygen vacancies inside the barrier layer of the film is 8.5∙10-16 cm2/s and varies weakly with the potential and the content of sodium fluoride in solution. Microscopic and profilometric studies show the development of the surface of the NiSi electrode during anodic etching.

Parametric Effect of Sodium Hydroxide and Sodium Carbonate on the Potency of a Degreaser

OpenAIRE

Babatope Abimbola Olufemi

2016-01-01

Experimental and statistical analysis was carried out on the comparative effect of sodium hydroxide and sodium carbonate on the potency of a laboratory produced degreaser in this work. The materials used include; octadecyl benzene sulphonic acid, sodium hydroxide, sodium carbonate, sodium metasilicate, carboxyl methyl cellulose (C.M.C), formadelhyde, perfume, colourant and distilled water. Different samples of degreaser were produced with varying composition of sodium hydroxide and sodium car...

Test Your Sodium Smarts

Science.gov (United States)

... You may be surprised to learn how much sodium is in many foods. Sodium, including sodium chloride ... foods with little or no salt. Test your sodium smarts by answering these 10 questions about which ...

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1983-01-01

Ion-Selective Electrode Reviews, Volume 5 is a collection of articles that covers ion-speciation. The book aims to present the advancements of the range and capabilities of selective ion-sensors. The topics covered in the selection are neutral carrier based ion-selective electrodes; reference electrodes and liquid junction effects in ion-selective electrode potentiometry; ion transfer across water/organic phase boundaries and analytical; and carbon substrate ion-selective electrodes. The text will be of great use to chemists and chemical engineers.

Characterisation of nano-interdigitated electrodes

Energy Technology Data Exchange (ETDEWEB)

Skjolding, L H D; Ribayrol, A; Montelius, L [Division of Solid State Physics, Lund University, Box 118, SE-221 00 Lund (Sweden); Spegel, C [Department of Analytical Chemistry Lund University, Box 124, SE-221 00 Lund (Sweden); Emneus, J [MIC - Department of Micro and Nanotechnology, DTU - Building 345 East, DK-2800 Kgs. Lyngby (Denmark)], E-mail: lars_henrik.daehli_skjolding@ftf.lth.se

2008-03-15

Interdigitated electrodes made up of two individually addressable interdigitated comb-like electrode structures have frequently been suggested as ultra sensitive electrochemical biosensors. Since the signal enhancement effects due to cycling of the reduced and oxidized species are strongly dependent on the inter electrode distances, since the nature of the enhancement is due to overlying diffusion layers, interdigitated electrodes with an electrode separation of less then one micrometer are desired for maximum signal amplification. Fabrication of submicron structures can only be made by advanced lithography techniques. By use of electron beam lithography we have fabricated arrays of interdigitated electrodes with an electrode separation distance of 200 nm and an electrode finger width of likewise 200 nm. The entire electrode structure is 100 micrometre times 100 micrometre, and the active electrode area is dictated by the opening in the passivation layer, that is defined by UV lithography. Here we report measurements of redox cycling of ferrocyanide by coupled cyclic voltammograms, where the potential at one of the working electrodes are varied and either an oxidising or reducing potential is applied to the complimentary interdigitated electrode. The measurements show fast conversion and high collection efficiency round 87% as expected for nano-interdigitated electrodes.

Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

Directory of Open Access Journals (Sweden)

Shi C

2010-01-01

Full Text Available Abstract Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0–3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g−1 was observed for the sample with a specific mass of 89 μg cm−2 at a scan rate of 2 mV s−1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES.

Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

Science.gov (United States)

Shi, C.; Zhitomirsky, I.

2010-03-01

Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0-3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC) in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g-1 was observed for the sample with a specific mass of 89 μg cm-2 at a scan rate of 2 mV s-1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES).

Methods to Compose Sodium Fire Extinguishing Equipment on Sodium Test Facility

Energy Technology Data Exchange (ETDEWEB)

Kim, B H; Kim, J M; Jeong, J Y; Choi, B H

2008-06-15

Sodium fire is graded 'D' and it is difficult to extinguish sodium fire. In this report, the characteristics of sodium fire and the methods composing the suitable fire extinguishing systems to suppress fire effectively were described.

Methods to Compose Sodium Fire Extinguishing Equipment on Sodium Test Facility

International Nuclear Information System (INIS)

Kim, B. H.; Kim, J. M.; Jeong, J. Y.; Choi, B. H.

2008-06-01

Sodium fire is graded 'D' and it is difficult to extinguish sodium fire. In this report, the characteristics of sodium fire and the methods composing the suitable fire extinguishing systems to suppress fire effectively were described

Electrode assemblies, plasma apparatuses and systems including electrode assemblies, and methods for generating plasma

Science.gov (United States)

Kong, Peter C; Grandy, Jon D; Detering, Brent A; Zuck, Larry D

2013-09-17

Electrode assemblies for plasma reactors include a structure or device for constraining an arc endpoint to a selected area or region on an electrode. In some embodiments, the structure or device may comprise one or more insulating members covering a portion of an electrode. In additional embodiments, the structure or device may provide a magnetic field configured to control a location of an arc endpoint on the electrode. Plasma generating modules, apparatus, and systems include such electrode assemblies. Methods for generating a plasma include covering at least a portion of a surface of an electrode with an electrically insulating member to constrain a location of an arc endpoint on the electrode. Additional methods for generating a plasma include generating a magnetic field to constrain a location of an arc endpoint on an electrode.

Near-Electrode Imager

Energy Technology Data Exchange (ETDEWEB)

Rathke, Jerome W.; Klingler, Robert J.; Woelk, Klaus; Gerald, Rex E.,II

1999-05-01

An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager use the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

A disposable electrochemical immunosensor arrays using 4-channel screen-printed carbon electrode for simultaneous detection of Escherichia coli O157:H7 and Enterobacter sakazakii

International Nuclear Information System (INIS)

Dou, Wenchao; Tang, Weilu; Zhao, Guangying

2013-01-01

An electrochemical immunosensor for Escherichia coli O157:H7 (E. coli O157:H7) and Enterobacter sakazakii (E. sakazakii) detection using carbon screen-printed low-density arrays is reported. The sensors were fabricated based on screen-printed carbon arrays containing four carbon working electrode, an integrated carbon counter electrodes and an integrated Ag/AgCl reference electrode. Multi-walled carbon nanotubes (MWCNTs)/sodium alginate (SA)/carboxymethyl chitosan (CMC) composite films were coated on all the working electrodes to enhance the sensitization of the electrode. Horseradish peroxidases (HRP) labeled antibodies of two bacteria were immobilize on different working electrode of the same screen-printed electrode respectively. The immobilization of MWCNTs, HRP labeled antibodies onto the screen-printed carbon electrodes was examined using atom force microscopy (AFM) and cyclic voltammetry (CV). The analytical performance of proposed immunosensor arrays toward E. sakazakii and E. coli O157:H7 was investigated by AFM and CV. Under optimal conditions, the linear range of E. sakazakii and E. coli O157:H7 were from 10 4 to 10 10 cfu/ml, with a detection limit of 4.57 × 10 3 cfu/ml (S/N = 3) and 3.27 × 10 3 cfu/ml (S/N = 3), respectively. The specificity, reproducibility, stability and accuracy of the proposed immunosensor arrays were also evaluated. Two antibodies modified work electrodes were tested and compared in terms of sensitivity and ability to recognize different pathogenic biological species

Transformation of sodium from the Rapsodie fast breeder reactor into sodium hydroxide

International Nuclear Information System (INIS)

Roger, J.; Latge, C.; Rodriguez, G.

1994-01-01

One of the major problems raised by decommissioning a fast breeder reactor (FBR) concerns the disposal of the sodium coolant. The Desora operation was undertaken to eliminate the Rapsodie primary sodium as part of the partial decommissioning program, and to develop an operational sodium treatment unit for other needs. The process involves reacting small quantities of sodium in water inside a closed vessel, producing aqueous sodium hydroxide and hydrogen gas. It is described in this work. (O.L.). 4 figs

Sodium fire protection

International Nuclear Information System (INIS)

Raju, C.; Kale, R.D.

1979-01-01

Results of experiments carried out with sodium fires to develop extinguishment techniques are presented. Characteristics, ignition temperature, heat evolution and other aspects of sodium fires are described. Out of the powders tested for extinguishment of 10 Kg sodium fires, sodium bi-carbonate based dry chemical powder has been found to be the best extinguisher followed by large sized vermiculite and then calcium carbonate powders distributed by spray nozzles. Powders, however, do not extinguish large fires effectively due to sodium-concrete reaction. To control large scale fires in a LMFBR, collection trays with protective cover have been found to cause oxygen starvation better than flooding with inert gas. This system has an added advantage in that there is no damage to the sodium facilities as has been in the case of powders which often contain chlorine compounds and cause stress corrosion cracking. (M.G.B.)

A study of atomic interaction between suspended nanoparticles and sodium atoms in liquid sodium

International Nuclear Information System (INIS)

Saito, Jun-ichi; Ara, Kuniaki

2010-01-01

A feasibility study of suppression of the chemical reactivity of sodium itself using an atomic interaction between nanoparticles and sodium atoms has been carried out. We expected that the atomic interaction strengthens when the nanoparticle metal is the transition element which has a major difference in electronegativity from sodium. We also calculated the atomic interaction between nanoparticle and sodium atoms. It became clear that the atomic bond between the nanoparticle atom and the sodium atom is larger than that between sodium atoms, and the charge transfer takes place to the nanoparticle atom from the sodium atom. Using sodium with suspended nanoparticles, the fundamental physical properties related to the atomic interaction were investigated to verify the atomic bond. The surface tension of sodium with suspended nanoparticles increased, and the evaporation rate of sodium with suspended nanoparticles also decreased compared with that of sodium. Therefore the presence of the atomic interaction between nanoparticles and sodium was verified from these experiments. Because the fundamental physical property changes by the atomic interaction, we expected changes in the chemical reactivity characteristics. The chemical reaction properties of sodium with suspended nanoparticles with water were investigated experimentally. The released reaction heat and the reaction rate of sodium with suspended nanoparticles were reduced than those of sodium. The influence of the charge state of nanoparticle on the chemical process with water was theoretically investigated to speculate on the cause of reaction suppression. The potential energy in both primary and side reactions changed by the charge transfer, and the free energy of activation of the reaction with water increased. Accordingly, the reaction barrier also increased. This suggests there is a possibility of the reduction in the reaction of sodium by the suspension of nanoparticles. Consequently the possibility of the

Internal reflection spectroscopic analysis of sulphide mineral surfaces

International Nuclear Information System (INIS)

Kaoma, J.

1989-01-01

To establish the reason for flotation of sulfide minerals in the absence of any conventional collector, internal reflection spectroscopic analysis (IRS) of their surfaces was conducted. sulfur, sulfates, thiosulfates, and hydrocarbonates have been detected on the surface of as-grand sulfide minerals. On sodium sulfide-treated surfaces, both sulfur and polysulfide have also been found to be present. From these findings, the flotation of sulfide minerals without collectors is discussed. (author). 26 refs

Non-noble metal graphene oxide-copper (II) ions hybrid electrodes for electrocatalytic hydrogen evolution reaction

KAUST Repository

Muralikrishna, S.

2015-08-25

Non-noble metal and inexpensive graphene oxide-copper (II) ions (GO-Cu2+) hybrid catalysts have been explored for the hydrogen evolution reaction (HER). We were able to tune the binding abilities of GO toward the Cu2+ ions and hence their catalytic properties by altering the pH. We have utilized the oxygen functional moieties such as carboxylate, epoxide, and hydroxyl groups on the edge and basal planes of the GO for binding the Cu2+ ions through dative bonds. The GO-Cu2+ hybrid materials were characterized by cyclic voltammetry in sodium acetate buffer solution. The morphology of the hybrid GO-Cu2+ was characterized by atomic force microscopy. The GO-Cu2+ hybrid electrodes show good electrocatalytic activity for HER with low overpotential in acidic solution. The Tafel slope for the GO-Cu2+ hybrid electrode implies that the primary discharge step is the rate determining step and HER proceed with Volmer step. © 2015 American Institute of Chemical Engineers Environ Prog.

Final report on the safety assessment of sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, sodium metabisulfite and potassium metabisulfite.

Science.gov (United States)

Nair, Bindu; Elmore, Amy R

2003-01-01

Sodium Sulfite, Ammonium Sulfite, Sodium Bisulfite, Potassium Bisulfite, Ammonium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite are inorganic salts that function as reducing agents in cosmetic formulations. All except Sodium Metabisulfite also function as hair-waving/straightening agents. In addition, Sodium Sulfite, Potassium Sulfite, Sodium Bisulfite, and Sodium Metabisulfite function as antioxidants. Although Ammonium Sulfite is not in current use, the others are widely used in hair care products. Sulfites that enter mammals via ingestion, inhalation, or injection are metabolized by sulfite oxidase to sulfate. In oral-dose animal toxicity studies, hyperplastic changes in the gastric mucosa were the most common findings at high doses. Ammonium Sulfite aerosol had an acute LC(50) of >400 mg/m(3) in guinea pigs. A single exposure to low concentrations of a Sodium Sulfite fine aerosol produced dose-related changes in the lung capacity parameters of guinea pigs. A 3-day exposure of rats to a Sodium Sulfite fine aerosol produced mild pulmonary edema and irritation of the tracheal epithelium. Severe epithelial changes were observed in dogs exposed for 290 days to 1 mg/m(3) of a Sodium Metabisulfite fine aerosol. These fine aerosols contained fine respirable particle sizes that are not found in cosmetic aerosols or pump sprays. None of the cosmetic product types, however, in which these ingredients are used are aerosolized. Sodium Bisulfite (tested at 38%) and Sodium Metabisulfite (undiluted) were not irritants to rabbits following occlusive exposures. Sodium Metabisulfite (tested at 50%) was irritating to guinea pigs following repeated exposure. In rats, Sodium Sulfite heptahydrate at large doses (up to 3.3 g/kg) produced fetal toxicity but not teratogenicity. Sodium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite were not teratogenic for mice, rats, hamsters, or rabbits at doses up to 160 mg/kg. Generally, Sodium Sulfite, Sodium

Influence of sodium carbonate on decomposition of formic acid by pulsed discharge plasma inside bubble in water

Science.gov (United States)

Iwabuchi, Masashi; Takahashi, Katsuyuki; Takaki, Koichi; Satta, Naoya

2016-07-01

The influence of sodium carbonate on the decomposition of formic acid by discharge inside bubbles in water was investigated experimentally. Oxygen or argon gases were injected into the water through a vertically positioned glass tube, in which the high-voltage wire electrode was placed to generate plasmas at low applied voltage. The concentration of formic acid was determined by ion chromatography. In the case of sodium carbonate additive, the pH increased owing to the decomposition of the formic acid. In the case of oxygen injection, the percentage of conversion of formic acid increased with increasing pH because the reaction rate of ozone with formic acid increased with increasing pH. In the case of argon injection, the percentage of conversion was not affected by the pH owing to the high rate loss of hydroxyl radicals.

Analytical study of sodium combustion phenomena under sodium leak accidents

International Nuclear Information System (INIS)

Kim, Byung Ho; Jeong, J. Y.; Jeong, K. C.; Kim, T. J.; Choi, J. H.

2001-12-01

The rise of temperature and pressure, the release of aerosol in the buildings as a result of sodium fire must be considered for the safety measures of LMR. Therefore for the safety of the LMR, it is necessary to understand the characteristics of sodium fire, resulting from the various type of leakage. ASSCOPS(Analysis of Simultaneous Sodium Combustion in Pool and Spray) is the computer code for the analysis of the thermal consequence of sodium leak and fire in LMR that has been developed by Japan Nuclear Cycle Development Institute(JNC) in Japan. In this study, a preliminary analysis of sodium leak and fire accidents in S/G building of KALIMER is made by using ASSCOPS code. Various phenomena of interest are spray and pool burning, peak pressure, temperature change, local structure temperature, aerosol behavior, drain system into smothering tank, ventilation characteristics at each cell with the safety venting system and nitrogen injection system. In this calculation, the dimension of the S/G building was chosen in accordance with the selected options of LMR name KALIMER(Korea). As a result of this study, it was shown that subsequent effect of sodium fire depended upon whether the sodium continued to leak from the pipe or not, whether the ventilation system was running, whether the inert gas injection system was provided, whether the sodium on floor was drained into the smothering tank or not, whether the building was sealed or not, etc. Specially the excessive rise of pressure into each cell was prevented by installing the pressure release plates on wall of the building

Synthesis of TiC Nanoparticles Anchored on Hollow Carbon Nanospheres for Enhanced Polysulfide Adsorption in Li-S Batteries.

Science.gov (United States)

Cao, Bokai; Chen, Yong; Li, De; Yin, Lihong; Mo, Yan

2016-12-08

A novel spatial confinement strategy based on a carbon/TiO 2 /carbon sandwich structure is proposed to synthesize TiC nanoparticles anchored on hollow carbon nanospheres (TiC@C) through a carbothermal reduction reaction. During the synthesis process, two carbon layers not only serve as reductant to convert TiO 2 into TiC nanoparticles, but also create a spatial confinement to suppress the aggregation of TiO 2 , resulting in the formation of well-dispersed TiC nanoparticles. This unique TiC@C structure shows an outstanding long-term cycling stability at high rates owing to the strong physical and chemical adsorption of lithium polysulfides (i.e., a high capacity of 732.6 mA h g -1 at 1600 mA g -1 ) and it retains a capacity of 443.2 mA h g -1 after 1000 cycles, corresponding to a decay rate of only 0.0395 % per cycle. Therefore, this unique TiC@C composite could be considered as an important candidate for the cathode material in Li-S batteries. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrolyte transport in distal colon of sodium-depleted rats: Effect of sodium repletion

International Nuclear Information System (INIS)

Turnamian, S.G.; Binder, H.J.

1988-01-01

Dietary sodium depletion increases plasma aldosterone level and, as a result, induces amiloride-sensitive electrogenic sodium absorption and electrogenic potassium secretion and stimulates Na + -K + -ATPase activity in rat distal colon, while inhibiting electroneutral sodium chloride absorption. To assess the events that occur as the aldosterone-stimulated colon reverts to normal, unidirectional 22 Na and 36 Cl fluxes were measured under voltage-clamp conditions across isolated distal colonic mucosa of rats that were initially dietary sodium depleted for 7 days and then sodium repleted for varying periods of time before the study. Within 8 h of dietary sodium repletion, plasma aldosterone level and Na + -K + -ATPase activity declined to normal, amiloride-sensitive electrogenic sodium absorption decreased by >90%, and active electrogenic potassium secretion also decreased markedly. In contrast, electroneutral sodium chloride absorption did not completely return to levels seen in normal animals until ∼64-68 h. These results demonstrate that maintenance of electrogenic sodium absorption and potassium secretion are directly dependent on elevated plasma aldosterone levels. The inhibition of electroneutral sodium absorption, although initiated by excess aldosterone, persists after normalization of the plasma aldosterone level, thereby implying that the inhibition is dependent on additional factor(s)

Sodium vapor deposition onto a horizontal flat plate above liquid sodium surface, 2

International Nuclear Information System (INIS)

Kudo, Kazuhiko; Hirata, Masaru.

1977-01-01

The sodium vapor deposition onto a horizontal flat plate above liquid sodium surface was studied. The analysis was performed by assuming that the sodium mist is emitted into the main flow without condensation and then grows up in the main flow and drops on the sodium surface. The effects of growth of sodium mist to the system were investigated. The model of the phenomena is the sodium deposition onto a horizontal flat plate which is placed above the sodium surface with the medium cover gas. One-dimensional analysis can be done. The rate of deposition is greatly reduced when the temperature of the flat plate is lowered. For the analysis of this phenomena, it is assumed that the sodium mist grows by condensation. One of results is that the real state may be the state between the state that the condensation of mist is made in the boundary layer and the state that the mist is condensed in the main flow. Others are that there is no effect of sodium mist condensation on the rate of deposition, and that the rate of the vaporization of sodium is given by the original and the modified model. (Kato, T.)

Electrochemical performance of CuNCN for sodium ion batteries and comparison with ZnNCN and lithium ion batteries

Science.gov (United States)

Eguia-Barrio, A.; Castillo-Martínez, E.; Klein, F.; Pinedo, R.; Lezama, L.; Janek, J.; Adelhelm, P.; Rojo, T.

2017-11-01

Transition metal carbodiimides (TMNCN) undergo conversion reactions during electrochemical cycling in lithium and sodium ion batteries. Micron sized copper and zinc carbodiimide powders have been prepared as single phase as confirmed by PXRD and IR and their thermal stability has been studied in air and nitrogen atmosphere. CuNCN decomposes at ∼250 °C into CuO or Cu while ZnNCN can be stable until 400 °C and 800 °C in air and nitrogen respectively. Both carbodiimides were electrochemically analysed for sodium and lithium ion batteries. The electrochemical Na+ insertion in CuNCN exhibits a relatively high reversible capacity (300 mAh·g-1) which still indicates an incomplete conversion reaction. This incomplete reaction confirmed by ex-situ EPR analysis, is partly due to kinetic limitations as evidenced in the rate capability experiments and in the constant potential measurements. On the other hand, ZnNCN shows incomplete conversion reaction but with good capacity retention and lower hysteresis as negative electrode for sodium ion batteries. The electrochemical performance of these materials is comparable to that of other materials which operate through displacement reactions and is surprisingly better in sodium ion batteries in comparison with lithium ion batteries.

Insulating electrodes: a review on biopotential front ends for dielectric skin–electrode interfaces

International Nuclear Information System (INIS)

Spinelli, Enrique; Haberman, Marcelo

2010-01-01

Insulating electrodes, also known as capacitive electrodes, allow acquiring biopotentials without galvanic contact with the body. They operate with displacement currents instead of real charge currents, and the electrolytic electrode–skin interface is replaced by a dielectric film. The use of insulating electrodes is not the end of electrode interface problems but the beginning of new ones: coupling capacitances are of the order of pF calling for ultra-high input impedance amplifiers and careful biasing, guarding and shielding techniques. In this work, the general requirements of front ends for capacitive electrodes are presented and the different contributions to the overall noise are discussed and estimated. This analysis yields that noise bounds depend on features of the available devices as current and voltage noise, but the final noise level also depends on parasitic capacitances, requiring a careful shield and printed circuit design. When the dielectric layer is placed on the skin, the present-day amplifiers allow achieving noise levels similar to those provided by wet electrodes. Furthermore, capacitive electrode technology allows acquiring high quality ECG signals through thin clothes. A prototype front end for capacitive electrodes was built and tested. ECG signals were acquired with these electrodes in direct contact with the skin and also through cotton clothes 350 µm thick. They were compared with simultaneously acquired signals by means of wet electrodes and no significant differences were observed between both output signals

Towards highly stable storage of sodium ions: a porous Na(3)V(2)(PO(4))(3)/C cathode material for sodium-ion batteries.

Science.gov (United States)

Shen, Wei; Wang, Cong; Liu, Haimei; Yang, Wensheng

2013-10-18

A porous Na3 V2 (PO4 )3 cathode material coated uniformly with a layer of approximately 6 nm carbon has been synthesized by the sol-gel method combined with a freeze-drying process. The special porous morphology and structure significantly increases the specific surface area of the material, which greatly enlarges the contact area between the electrode and electrolyte, and consequently supplies more active sites for sodium ions. When employed as a cathode material of sodium-ion batteries, this porous Na3 V2 (PO4 )3 /C exhibits excellent rate performance and cycling stability; for instance, it shows quite a flat potential plateau at 3.4 V in the potential window of 2.7-4.0 V versus Na(+) /Na and delivers an initial capacity as high as 118.9 and 98.0 mA h g(-1) at current rates of 0.05 and 0.5 C, respectively, and after 50 cycles, a good capacity retention of 92.7 and 93.6 % are maintained. Moreover, even when the discharge current density is increased to 5 C (590 mA g(-1) ), an initial capacity of 97.6 mA h g(-1) can still be achieved, and an exciting capacity retention of 88.6 % is obtained after 100 cycles. The good cycle performance, excellent rate capability, and moreover, the low cost of Na3 V2 (PO4 )3 /C suggest that this material is a promising cathode for large-scale sodium-ion rechargeable batteries. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Schiff Base modified on CPE electrode and PCB gold electrode for selective determination of silver ion

Science.gov (United States)

Leepheng, Piyawan; Suramitr, Songwut; Phromyothin, Darinee

2017-09-01

The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag+. The determination of silver ions using the modified electrodes depended linearly on Ag+ concentration in the range 1×10-10 M to 1×10-7 M, with cyclic voltammetry sensitivity were 2.51×108 μAM-1 and 1.88×108 μAM-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10-9 M and 1.99×10-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag+ in real samples.

Operating experience with sodium valves in the TNO-sodium test facilities

International Nuclear Information System (INIS)

Gasselt, M.L.G. van

1974-01-01

The development of sodium components for the SNR-300 in Holland has reached the stage where full scale testing in sodium has almost been finished and construction is at its height. It is against this background that a review is given of the weaknesses in one area or the other of the commercially available types of sodium valves used in TNO's smaller test facilities at Apeldoorn and TNO's 50 MW sodium components test facility at Hengelo. (U.S.)

Voltammetric sensing of paracetamole, dopamine and 4-aminophenol at a glassy carbon electrode coated with gold nanoparticles and an organophillic layered double hydroxide

International Nuclear Information System (INIS)

Yin, H.; Shang, K.; Meng, X.; Ai, S.

2011-01-01

A differential pulse voltammetric method was developed for the simultaneous determination of paracetamole, 4-aminophenol and dopamine at pH 7.0 using a glassy carbon electrode (GCE) coated with gold nanoparticles (AuNPs) and a layered double hydroxide sodium modified with dodecyl sulfate (SDS-LDH). The modified electrode displays excellent redox activity towards paracetamole, and the redox current is increased (and the corresponding over-potential decreased) compared to those of the bare GCE, the AuNPs-modified GCE, and the SDS-LDH-modified GCE. The modified electrode enables the determination of paracetamole in the concentration range from 0.5 to 400 μM, with a detection limit of 0.13 μM (at an S/N of 3). The sensor was successfully applied to the simultaneous determination of paracetamole and dopamine, and of paracetamole and 4-aminophenol, respectively, in pharmaceutical tablets and in spiked human serum samples. (author)

Voltammetry at micro-mesh electrodes

Directory of Open Access Journals (Sweden)

Wadhawan Jay D.

2003-01-01

Full Text Available The voltammetry at three micro-mesh electrodes is explored. It is found that at sufficiently short experimental durations, the micro-mesh working electrode first behaves as an ensemble of microband electrodes, then follows the behaviour anticipated for an array of diffusion-independent micro-ring electrodes of the same perimeter as individual grid-squares within the mesh. During prolonged electrolysis, the micro-mesh electrode follows that behaviour anticipated theoretically for a cubically-packed partially-blocked electrode. Application of the micro-mesh electrode for the electrochemical determination of carbon dioxide in DMSO electrolyte solutions is further illustrated.

Solid phase microbial fuel cell (SMFC) for harnessing bioelectricity from composite food waste fermentation: influence of electrode assembly and buffering capacity.

Science.gov (United States)

Mohan, S Venkata; Chandrasekhar, K

2011-07-01

Solid phase microbial fuel cells (SMFC; graphite electrodes; open-air cathode) were designed to evaluate the potential of bioelectricity production by stabilizing composite canteen based food waste. The performance was evaluated with three variable electrode-membrane assemblies. Experimental data depicted feasibility of bioelectricity generation from solid state fermentation of food waste. Distance between the electrodes and presence of proton exchange membrane (PEM) showed significant influence on the power yields. SMFC-B (anode placed 5 cm from cathode-PEM) depicted good power output (463 mV; 170.81 mW/m(2)) followed by SMFC-C (anode placed 5 cm from cathode; without PEM; 398 mV; 53.41 mW/m(2)). SMFC-A (PEM sandwiched between electrodes) recorded lowest performance (258 mV; 41.8 mW/m(2)). Sodium carbonate amendment documented marked improvement in power yields due to improvement in the system buffering capacity. SMFCs operation also documented good substrate degradation (COD, 76%) along with bio-ethanol production. The operation of SMFC mimicked solid-sate fermentation which might lead to sustainable solid waste management practices. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electrode assembly for a lithium ion battery, process for the production of such electrode assembly, and lithium ion battery comprising such electrode assemblies

NARCIS (Netherlands)

Mulder, F.M.; Wagemaker, M.

2013-01-01

The invention provides an electrode assembly for a lithium ion battery, the electrode assembly comprising a lithium storage electrode layer on a current collector, wherein the lithium storage electrode layer is a porous layer having a porosity in the range of -35 %, with pores having pore widths in

Astrocyte Sodium Signalling and Panglial Spread of Sodium Signals in Brain White Matter.

Science.gov (United States)

Moshrefi-Ravasdjani, Behrouz; Hammel, Evelyn L; Kafitz, Karl W; Rose, Christine R

2017-09-01

In brain grey matter, excitatory synaptic transmission activates glutamate uptake into astrocytes, inducing sodium signals which propagate into neighboring astrocytes through gap junctions. These sodium signals have been suggested to serve an important role in neuro-metabolic coupling. So far, it is unknown if astrocytes in white matter-that is in brain regions devoid of synapses-are also able to undergo such intra- and intercellular sodium signalling. In the present study, we have addressed this question by performing quantitative sodium imaging in acute tissue slices of mouse corpus callosum. Focal application of glutamate induced sodium transients in SR101-positive astrocytes. These were largely unaltered in the presence of ionotropic glutamate receptors blockers, but strongly dampened upon pharmacological inhibition of glutamate uptake. Sodium signals induced in individual astrocytes readily spread into neighboring SR101-positive cells with peak amplitudes decaying monoexponentially with distance from the stimulated cell. In addition, spread of sodium was largely unaltered during pharmacological inhibition of purinergic and glutamate receptors, indicating gap junction-mediated, passive diffusion of sodium between astrocytes. Using cell-type-specific, transgenic reporter mice, we found that sodium signals also propagated, albeit less effectively, from astrocytes to neighboring oligodendrocytes and NG2 cells. Again, panglial spread was unaltered with purinergic and glutamate receptors blocked. Taken together, our results demonstrate that activation of sodium-dependent glutamate transporters induces sodium signals in white matter astrocytes, which spread within the astrocyte syncytium. In addition, we found a panglial passage of sodium signals from astrocytes to NG2 cells and oligodendrocytes, indicating functional coupling between these macroglial cells in white matter.

Characterization of electrode materials for lithium ion and sodium ion batteries using synchrotron radiation techniques.

Science.gov (United States)

Doeff, Marca M; Chen, Guoying; Cabana, Jordi; Richardson, Thomas J; Mehta, Apurva; Shirpour, Mona; Duncan, Hugues; Kim, Chunjoong; Kam, Kinson C; Conry, Thomas

2013-11-11

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g. changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g. on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

The Corrosion Inhibition Characteristics of Sodium Nitrite Using an On-line Corrosion Rate Measurement System

International Nuclear Information System (INIS)

Park, Mal-Yong; Kang, Dae-Jin; Moon, Jeon-Soo

2015-01-01

An on-line corrosion rate measurement system was developed using a personal computer, a data acquisition board and program, and a 2-electrode corrosion probe. Reliability of the developed system was confirmed with through comparison test. With this system, the effect of sodium nitrite (NaNO 2 ) as a corrosion inhibitor were studied on iron and aluminum brass that were immersed in sodium chloride (NaCl) solution. Corrosion rate was measured based on the linear polarization resistance method. The corrosion rates of aluminum brass and iron in 1% NaCl solutions were measured to be 0.290 mm per year (mmpy) and 0.2134 mmpy, respectively. With the addition of 200 ppm of NO 2 - , the corrosion rates decreased to 0.0470 mmpy and 0.0254 mmpy. The addition of NO 2 - caused a decrease in corrosion rates of both aluminum brass and iron, yet the NO 2 - acted as a more effective corrosion inhibitor for iron. than aluminum brass

Dynamic thermal baffle on lower head of FBR sodium-sodium intermediate heat exchanger

International Nuclear Information System (INIS)

Charbonnel, A.; Foussat, C.

1981-01-01

The cover head of the heat exchanger is bathed on the one side by the primary sodium of the 'cold' header of the vessel and on the other side by the secondary sodium which feeds the heat exchange tube bank through the lower tubesheet. In the case of transient or permanent operating conditions at partial ratings, there are large temperature differences between the inner sodium (inlet temperature conditions of secondary sodium) and the outer sodium (mean temperature conditions in the primary sodium outlet port), hence the necessity of designing a thermal baffle which protects the head and its connection to the tubesheet. A 'static' thermal baffle consisting of a thick steel plate enclosing static sodium around the head proves inadequate during transient operating conditions. This is why a 'dynamic' thermal baffle is used whose design is based on the fact that the primary sodium in the lower part of the outlet port is always at a temperature close to that of the secondary sodium in the inlet header and the head. The primary sodium is taken from the bottom of the outlet port by a ring deflector and circulates in an annulus created by a double housing and the head. It flows out through openings in the lower part of the housing. (orig./GL)

Small liquid sodium leaks

International Nuclear Information System (INIS)

Dufresne, J.; Rochedereux, Y.; Antonakas, D.; Casselman, C.; Malet, J.C.

1986-05-01

Usually, pessimistic considerations inassessing the safety of secondary sodium loops in LMFBR reactor lead to assume guillotine rupture releasing a large amount of sodium estimate the consequences of large sodium fires. In order to reduce these consequences, one has to detect the smallest leak as soon as possible and to evaluate the future of an initial small leak. Analysis of the relationship between crack size and sodium outflow rate; Analysis of a sodium pipe with a small open crack

Multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

Science.gov (United States)

Farahmandi, C. Joseph; Dispennette, John M.; Blank, Edward; Kolb, Alan C.

1999-01-19

A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator sleeve is inserted over the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal. The height of the interleaved stack is somewhat greater than the inside height of the closed capacitor case, thereby requiring compression of the interleaved electrode stack when placed inside of the case, and thereby maintaining the interleaved electrode stack under modest constant pressure. The closed capacitor case is filled with an electrolytic solution and sealed. A preferred electrolytic solution is made by dissolving an appropriate salt into acetonitrile (CH.sub.3 CN). In one embodiment, the two parts of the capacitor case are conductive and function as the capacitor terminals.

Effects of topical flurbiprofen sodium, diclofenac sodium, ketorolac ...

African Journals Online (AJOL)

To evaluate corneal sensitivity by using the Cochet-Bonnet® esthesiometer in normal canine eyes at different time points following instillation of three different topical non-steroidal anti-inflammatory drugs (flurbiprofen sodium 0.03%, diclofenac sodium 0.1% and ketorolac tromethamine 0.5%) and benzalkonium chloride ...

Investigation of Plugging of Narrow Sodium Channels by Sodium and Carbon Dioxide Interaction

Energy Technology Data Exchange (ETDEWEB)

Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong; Kim, Tae-joon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-10-15

The supercritical CO{sub 2} Brayton cycle system is known to be a promising power conversion system for improving the efficiency and preventing the sodium water reaction (SWR) of the current SFR concept using a Rankine steam cycle. PCHEs are known to have potential for reducing the volume occupied by the sodium-to-CO{sub 2} exchangers as well as the heat exchanger mass relative to traditional shell-and-tube heat exchangers. Here, we report a study on a plugging test by the interaction of sodium and CO{sub 2} to investigate design parameters of sodium channels in the realistic operating conditions. We investigated a plugging test by an interaction of sodium and CO{sub 2} with different cross sectional areas of the sodium channels. It was found that the flow rate of sodium decreased earlier and faster with a narrower cross sectional area compared to a wider one. Our experimental results are expected to be used for determining the sodium channel areas of PCHEs.

From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries

Science.gov (United States)

Hartmann, Pascal; Bender, Conrad L; Busche, Martin; Eufinger, Christine

2015-01-01

Summary Research devoted to room temperature lithium–sulfur (Li/S8) and lithium–oxygen (Li/O2) batteries has significantly increased over the past ten years. The race to develop such cell systems is mainly motivated by the very high theoretical energy density and the abundance of sulfur and oxygen. The cell chemistry, however, is complex, and progress toward practical device development remains hampered by some fundamental key issues, which are currently being tackled by numerous approaches. Quite surprisingly, not much is known about the analogous sodium-based battery systems, although the already commercialized, high-temperature Na/S8 and Na/NiCl2 batteries suggest that a rechargeable battery based on sodium is feasible on a large scale. Moreover, the natural abundance of sodium is an attractive benefit for the development of batteries based on low cost components. This review provides a summary of the state-of-the-art knowledge on lithium–sulfur and lithium–oxygen batteries and a direct comparison with the analogous sodium systems. The general properties, major benefits and challenges, recent strategies for performance improvements and general guidelines for further development are summarized and critically discussed. In general, the substitution of lithium for sodium has a strong impact on the overall properties of the cell reaction and differences in ion transport, phase stability, electrode potential, energy density, etc. can be thus expected. Whether these differences will benefit a more reversible cell chemistry is still an open question, but some of the first reports on room temperature Na/S8 and Na/O2 cells already show some exciting differences as compared to the established Li/S8 and Li/O2 systems. PMID:25977873

From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries

Directory of Open Access Journals (Sweden)

Philipp Adelhelm

2015-04-01

Full Text Available Research devoted to room temperature lithium–sulfur (Li/S8 and lithium–oxygen (Li/O2 batteries has significantly increased over the past ten years. The race to develop such cell systems is mainly motivated by the very high theoretical energy density and the abundance of sulfur and oxygen. The cell chemistry, however, is complex, and progress toward practical device development remains hampered by some fundamental key issues, which are currently being tackled by numerous approaches. Quite surprisingly, not much is known about the analogous sodium-based battery systems, although the already commercialized, high-temperature Na/S8 and Na/NiCl2 batteries suggest that a rechargeable battery based on sodium is feasible on a large scale. Moreover, the natural abundance of sodium is an attractive benefit for the development of batteries based on low cost components. This review provides a summary of the state-of-the-art knowledge on lithium–sulfur and lithium–oxygen batteries and a direct comparison with the analogous sodium systems. The general properties, major benefits and challenges, recent strategies for performance improvements and general guidelines for further development are summarized and critically discussed. In general, the substitution of lithium for sodium has a strong impact on the overall properties of the cell reaction and differences in ion transport, phase stability, electrode potential, energy density, etc. can be thus expected. Whether these differences will benefit a more reversible cell chemistry is still an open question, but some of the first reports on room temperature Na/S8 and Na/O2 cells already show some exciting differences as compared to the established Li/S8 and Li/O2 systems.

Liquid sodium pool fires

Energy Technology Data Exchange (ETDEWEB)

Casselman, C [DSN/SESTR, Centre de Cadarache, Saint-Paul-lez-Durance (France)

1979-03-01

Experimental sodium pool combustion results have led to a definition of the combustion kinetics, and have revealed the hazards of sodium-concrete contact reactions and the possible ignition of organic matter (paint) by hydration of sodium peroxide aerosols. Analysis of these test results shows that the controlling mechanism is sodium evaporation diffusion. (author)

Liquid sodium pool fires

International Nuclear Information System (INIS)

Casselman, C.

1979-01-01

Experimental sodium pool combustion results have led to a definition of the combustion kinetics, and have revealed the hazards of sodium-concrete contact reactions and the possible ignition of organic matter (paint) by hydration of sodium peroxide aerosols. Analysis of these test results shows that the controlling mechanism is sodium evaporation diffusion. (author)

Uncharged positive electrode composition

Science.gov (United States)

Kaun, Thomas D.; Vissers, Donald R.; Shimotake, Hiroshi

1977-03-08

An uncharged positive-electrode composition contains particulate lithium sulfide, another alkali metal or alkaline earth metal compound other than sulfide, e.g., lithium carbide, and a transition metal powder. The composition along with a binder, such as electrolytic salt or a thermosetting resin is applied onto an electrically conductive substrate to form a plaque. The plaque is assembled as a positive electrode within an electrochemical cell opposite to a negative electrode containing a material such as aluminum or silicon for alloying with lithium. During charging, lithium alloy is formed within the negative electrode and transition metal sulfide such as iron sulfide is produced within the positive electrode. Excess negative electrode capacity over that from the transition metal sulfide is provided due to the electrochemical reaction of the other than sulfide alkali metal or alkaline earth metal compound.

Polyamidoamine dendrimer-based binders for high-loading lithium–sulfur battery cathodes

Energy Technology Data Exchange (ETDEWEB)

Bhattacharya, Priyanka; Nandasiri, Manjula I.; Lv, Dongping; Schwarz, Ashleigh M.; Darsell, Jens T.; Henderson, Wesley A.; Tomalia, Donald A.; Liu, Jun; Zhang, Ji-Guang; Xiao, Jie

2016-01-01

Lithium-sulfur (Li-S) batteries are regarded as one of the most promising candidates for next generation energy storage systems because of their ultra high theoretical specific energy. To realize the practical application of Li-S batteries, however, a high S active material loading is essential (>70 wt% in the carbon-sulfur (C-S) composite cathode and >2 mg cm-2 in the electrode). A critical challenge to achieving this high capacity in practical electrodes is the dissolution of the longer lithium polysulfide reaction intermediates in the electrolyte (resulting in loss of active material from the cathode and contamination of the anode due to the polysulfide shuttle mechanism). The binder material used for the cathode is therefore crucial as this is a key determinant of the bonding interactions between the active material (S) and electronic conducting support (C), as well as the maintenance of intimate contact between the electrode materials and current collector. The battery performance can thus be directly correlated with the choice of binder, but this has received only minimal attention in the relevant Li-S battery published literature. Here, we investigated the application of polyamidoamine (PAMAM) dendrimers as functional binders in Li-S batteries—a class of materials which has been unexplored for electrode design. By using dendrimers, it is demonstrated that high S loadings (>4 mg cm-2) can be easily achieved using "standard" (not specifically tailored) materials and simple processing methods. An exceptional electrochemical cycling performance was obtained (as compared to cathodes with conventional linear polymeric binders such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR)) with >100 cycles and 85-98% capacity retention, thus demonstrating the significant utility of this new binder architecture which exhibits critical physicochemical properties and flexible nanoscale design parameters (CNDP's).

Investigation for the sodium leak Monju. Sodium fire test-II

International Nuclear Information System (INIS)

Uchiyama, Naoki; Takai, Toshihide; Nishimura, Masahiro; Miyahara, Shinya; Miyake, Osamu; Tanabe, Hiromi

2000-08-01

As a part of the work for investigating the sodium leak accident which occurred in the Monju reactor (hereinafter referred to as Monju), sodium fire test-II was carried out using the SOLFA-1 (Sodium Leak, Fire and Aerosol) facility at OEC/PNC. In the test, the piping, ventilation duct, grating and floor liner were all full-sized and arranged in a rectangular concrete cell in the same manner as in Monju. The main objectives of the test were to confirm the leak and burning behavior of sodium from the damaged thermometer, and the effects of the sodium fire on the integrity of the surrounding structure. The main conclusions obtained from the test are shown below: (1) Burning Behavior of Leaked Sodium : Images taken with a cameras in the test reveal that in the early stages of the sodium leak, the sodium dropped down out of the flexible tube in drips. (2) Damage to the Ventilation Duct and Grating : The temperature of the ventilation duct's inner surface fluctuated between approximately 600degC and 700degC. The temperature of the grating began rising at the outset of the test, then fluctuated between roughly 600degC and 900degC. The maximum temperature was about 1000degC. After the test, damage to the ventilation duct and the grating was found. Damage to the duct was greater than that at Monju. (3) Effects on the Floor Liner : The temperature of the floor liner under the leak point exceed 1,000degC at 3 hours and 20 minutes into the test. A post test inspection of the liner revealed five holes in an area about 1m x 1m square under the leak point. There was also a decrease of the liner thickness on the north and west side of the leak point. (4) Effects on Concrete : The post test inspection revealed no surface damage on either the concrete side walls or the ceiling. However, the floor concrete was eroded to a maximum depth 8 cm due to a sodium-concrete reaction. The compressive strength of the concrete was not degraded in spite of the thermal effect. (5) Chemical

Control of sodium fires and sodium-water reactions in breeder reactors

International Nuclear Information System (INIS)

Foerster, K.; Ruloff, G.; Voss, J.

1985-01-01

The excellent neutronic and thermodynamic properties of sodium as a fast-reactor coolant are somewhat counterbalanced by its high oxygen affinity. Because incidents like sodium fires and sodium-water reactions cannot be absolutely excluded, their effects and preventive measures have to be investigated. Characteristics and counter-measures are discussed. (orig.) [de

Glucose-assisted synthesis of Na3V2(PO4)3/C composite as an electrode material for high-performance sodium-ion batteries

Science.gov (United States)

Li, Guangqiang; Jiang, Danlu; Wang, Hui; Lan, Xinzheng; Zhong, Honghai; Jiang, Yang

2014-11-01

A novel electrode material for sodium-ion batteries (NIBs), Na3V2(PO4)3 with a rhombohedral, Na+ superionic conductor (NASICON)-type structure, was synthesised via a solid-state carbon-thermal reduction reaction assisted by mechanochemical activation. Electron microscopy analysis showed that the synthesised Na3V2(PO4)3 particles had an average size of 300 nm, being coated with a uniform layer of carbon 3 nm in thickness. As a cathode material, Na3V2(PO4)3/C exhibited an initial specific discharge capacity of 98.17 mAh g-1 at 0.1C for potentials ranging from 2.5 to 3.8 V. This was owing to the V3+/V4+ redox couple, which corresponded to the two-phase transition between Na3V2(PO4)3 and NaV2(PO4)3. The cathode lost 4.92% of its discharge specific capacity after 50 cycles. As an anode material, Na3V2(PO4)3/C exhibited an initial specific discharge capacity of 63.2 mAh g-1 at 0.1C for potentials ranging from 1.0 to 2.5 V. This was owing to the V2+/V3+ redox couple, which corresponded to the two-phase transition between Na3V2(PO4)3 and Na4V2(PO4)3. The anode lost approximately 5.41% of its discharge specific capacity after 50 cycles. The three-dimensional channel structure of NaV2(PO4)3 and the changes induced in its lattice parameters during the charge/discharge processes were simulated on the basis of density functional theory.

Sodium aerosol recovering device

International Nuclear Information System (INIS)

Fujimori, Koji; Ueda, Mitsuo; Tanaka, Kazuhisa.

1997-01-01

A main body of a recovering device is disposed in a sodium cooled reactor or a sodium cooled test device. Air containing sodium aerosol is sucked into the main body of the recovering device by a recycling fan and introduced to a multi-staged metal mesh filter portion. The air about against each of the metal mesh filters, and the sodium aerosol in the air is collected. The air having a reduced sodium aerosol concentration circulates passing through a recycling fan and pipelines to form a circulation air streams. Sodium aerosol deposited on each of the metal mesh filters is scraped off periodically by a scraper driving device to prevent clogging of each of the metal filters. (I.N.)

Sodium characterization during the starting period of a sodium loop

International Nuclear Information System (INIS)

Lievens, F.; Parmentier, C.; Soenen, M.

1976-01-01

A sodium loop for analytical chemistry studies has been built by S.C.K./C.E.N. at Mol Belgium. Its first working period was used to test analytical methods, to characterize the sodium and to define the operating parameters of the loop. This report covers the working parameters of the loop, the characterization of the filling sodium and its purity evolution during the first working period of the loop

Final report on the safety assessment of potassium silicate, sodium metasilicate, and sodium silicate.

Science.gov (United States)

Elmore, Amy R

2005-01-01

Potassium Silicate, Sodium Metasilicate, and Sodium Silicate combine metal cations with silica to form inorganic salts used as corrosion inhibitors in cosmetics. Sodium Metasilicate also functions as a chelating agent and Sodium Silicate as a buffering and pH adjuster. Sodium Metasilicate is currently used in 168 formulations at concentrations ranging from 13% to 18%. Sodium Silicate is currently used in 24 formulations at concentrations ranging from 0.3% to 55%. Potassium Silicate and Sodium Silicate have been reported as being used in industrial cleaners and detergents. Sodium Metasilicate is a GRAS (generally regarded as safe) food ingredient. Aqueous solutions of Sodium Silicate species are a part of a chemical continuum of silicates based on an equilibrium of alkali, water, and silica. pH determines the solubility of silica and, together with concentration, determines the degree of polymerization. Sodium Silicate administered orally is readily absorbed from the alimentary canal and excreted in the urine. The toxicity of these silicates has been related to the molar ratio of SiO2/Na2O and the concentration being used. The Sodium Metasilicate acute oral LD50 ranged from 847 mg/kg in male rats to 1349.3 mg/kg in female rats and from 770 mg/kg in female mice to 820 mg/kg in male mice. Gross lesions of variable severity were found in the oral cavity, pharynx, esophagus, stomach, larynx, lungs, and kidneys of dogs receiving 0.25 g/kg or more of a commercial detergent containing Sodium Metasilicate; similar lesions were also seen in pigs administered the same detergent and dose. Male rats orally administered 464 mg/kg of a 20% solution containing either 2.0 or 2.4 to 1.0 ratio of sodium oxide showed no signs of toxicity, whereas doses of 1000 and 2150 mg/kg produced gasping, dypsnea, and acute depression. Dogs fed 2.4 g/kg/day of Sodium Silicate for 4 weeks had gross renal lesions but no impairment of renal function. Dermal irritation of Potassium Silicate, Sodium

Electrochemical study of the interaction between dsDNA and copper(I) using carbon paste and hanging mercury drop electrode.

Science.gov (United States)

Stanić, Z; Girousi, S

2008-06-30

The interaction of copper(I) with double-stranded (ds) calf thymus DNA was studied in solution and at the electrode surface by means of transfer voltammetry using a carbon paste electrode (CPE) as working electrode in 0.2 M acetate buffer solution (pH 5.0). As a result of the interaction of Cu(I) between the base pairs of the dsDNA, the characteristic peaks of dsDNA, due to the oxidation of guanine and adenine, increased and after a certain concentration of Cu(I) a new peak at +1.37 V appeared, probably due to the formation of a purine-Cu(I) complex (dsDNA-Cu(I) complex). Accordingly, the interaction of copper(I) with calf thymus dsDNA was studied in solution as well as at the electrode surface using hanging mercury drop electrode (HMDE) by means of alternating current voltammetry (AC voltammetry) in 0.3 M NaCl and 50 mM sodium phosphate buffer (pH 8.5) as supporting electrolyte. Its interaction with DNA is shown to be time dependent. Significant changes in the characteristic peaks of dsDNA were observed after addition of higher concentration of Cu(I) to a solution containing dsDNA, as a result of the interaction between Cu(I) and dsDNA. All the experimental results indicate that Cu(I) can bind to DNA by electrostatic binding and form an association complex.

Korea advanced liquid metal reactor development - Development of measuring techniques of the sodium two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Kim, Moo Hwan; Cha, Jae Eun [Pohang University of Science and Technology, Pohang (Korea)

2000-04-01

The technology which models and measures the behavior of bubble in liquid sodium is very important to insure the safety of the liquid metal reactor. In this research, we designed/ manufactured each part and loop of experimental facility for sodium two phase flow, and applied a few possible methods, measured characteristic of two phase flow such as bubbly flow. A air-water loop similar to sodium loop on each measuring condition was designed/manufactured. This air-water loop was utilized to acquire many informations which were necessary in designing the two phase flow of sodium and manufacturing experimental facility. Before the manufacture of a electromagnetic flow meter for sodium, the experiment using each electromagnetic flow mete was developed and the air-water loop was performed to understand flow characteristics. Experiments for observing the signal characteristics of flow were performed by flowing two phase mixture into the electromagnetic flow mete. From these experiments, the electromagnetic flow meter was designed and constructed by virtual electrode, its signal processing circuit and micro electro magnet. It was developed to be applicable to low conductivity fluid very successfully. By this experiment with the electromagnetic flow meter, we observed that the flow signal was very different according to void fraction in two phase flow and that probability density function which was made by statistical signal treatment is also different according to flow patterns. From this result, we confirmed that the electromagnetic flow meter could be used to understand the parameters of two phase flow of sodium. By this study, the experimental facility for two phase flow of sodium was constricted. Also the new electromagnetic flow meter was designed/manufactured, and experimental apparatus for two phase flow of air-water. Finally, this study will be a basic tool for measurement of two phase flow of sodium. As the fundamental technique for the applications of sodium at

The Composite Insertion Electrode

DEFF Research Database (Denmark)

Atlung, Sven; Zachau-Christiansen, Birgit; West, Keld

1984-01-01

The specific energy obtainable by discharge of porous insertion electrodes is limited by electrolyte depletion in thepores. This can be overcome using a solid ion conductor as electrolyte. The term "composite" is used to distinguishthese electrodes from porous electrodes with liquid electrolyte...

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1985-01-01

Ion-Selective Electrode Reviews, Volume 7 is a collection of papers that covers the applications of electrochemical sensors, along with the versatility of ion-selective electrodes. The coverage of the text includes solid contact in membrane ion-selective electrodes; immobilized enzyme probes for determining inhibitors; potentiometric titrations based on ion-pair formation; and application of ion-selective electrodes in soil science, kinetics, and kinetic analysis. The text will be of great use to chemists and chemical engineers.

Study of the electrochemical behavior at low temperatures of green anodes for Lithium ion batteries prepared with anatase TiO2 and water soluble sodium carboxymethyl cellulose binder

International Nuclear Information System (INIS)

Mancini, M.; Nobili, F.; Tossici, R.; Marassi, R.

2012-01-01

Highlights: ► Water soluble CMC and PVDF binders are used to prepare anatase TiO 2 electrodes. ► The electrochemical behavior of the different electrodes is studied between 20 and −30 °C. ► CMC/TiO 2 anodes show lower ICL, lower polarization and higher low-temperature capacity at high rates than PVDF/TiO 2 anodes. ► Electrochemical Impedance Spectroscopy results show better kinetics for CMC/TiO 2 electrodes. - Abstract: The electrochemical behavior at low temperatures of anatase TiO 2 electrodes for Lithium ion batteries have been evaluated by galvanostatic cycles in the temperature range 20 to −30 °C. Two different manufacturing processes have been used to prepare anatase anodes containing water soluble sodium carboxymethyl cellulose (CMC) or poly(vinilydene fluoride) (PVDF) as binder. The low temperature performances at different charge/discharge rates of TiO 2 /CMC and TiO 2 /PVDF electrodes are compared and discussed in terms of irreversible capacity loss (ICL) at the first cycle, capacity retention and reversible capacity. The kinetics of the electrodes containing CMC or PVDF is evaluated by Electrochemical Impedance Spectroscopy.

Improving the Corrosion Inhibitive Strength of Sodium Sulphite in Hydrogen Cyanide Solution Using Sodium Benzoate

Directory of Open Access Journals (Sweden)

Muhammed Olawale Hakeem AMUDA

2008-12-01

Full Text Available The improvement in the inhibitive strength of sodium sulphite on corrosion of mild steel in hydrogen cyanide by adding sodium benzoate in regulated volume was investigated using the fundamental weight loss measurement.500 ppm concentration inhibitive mixtures of sodium benzoate and sodium sulphite in three different volume ratios (5/15, 10/10, 15/5 were formulated and studied for corrosion rate in 200ml hydrogen cyanide fluid. Result obtained indicates that the corrosion rate of mild steel in hydrogen cyanide in the presence of sodium benzoate/sodium sulphite inhibitive mixtures range 0.322mmpy to 1.1269mmpy across the three volumetric ratios considered. The 15ml5ml sodium benzoatesodium sulphite mixture had the best average corrosion rate of 0.5123mmpy.The corrosion rate followed reducing pattern after the first 200 hours of immersion. The average corrosion rate in the sodium benzoate / sodium sulphite mixture is less than the rate in sodium sulphite and the mixture is only effective after long time exposure.It is concluded that adding sodium benzoate to sodium sulphite in the volumetric ratio 155ml improves the inhibitive strength of sodium sulphite on the corrosion of mild steel in hydrogen cyanide environment.

Sulfur cathode integrated with multileveled carbon nanoflake-nanosphere networks for high-performance lithium-sulfur batteries

International Nuclear Information System (INIS)

Li, S.H.; Wang, X.H.; Xia, X.H.; Wang, Y.D.; Wang, X.L.; Tu, J.P.

2017-01-01

Tailored design/construction of high-quality sulfur/carbon composite cathode is critical for development of advanced lithium-sulfur batteries. We report a powerful strategy for integrated fabrication of sulfur impregnated into three-dimensional (3D) multileveled carbon nanoflake-nanosphere networks (CNNNs) by means of sacrificial ZnO template plus glucose carbonization. The multileveled CNNNs are not only utilized as large-area host/backbone for sulfur forming an integrated S/CNNNs composite electrode, but also serve as multiple carbon blocking barriers (nanoflake infrastructure andnanosphere superstructure) to physically confine polysulfides at the cathode. The designedself-supported S/CNNNs composite cathodes exhibit superior electrochemical performances with high capacities (1395 mAh g −1 at 0.1C, and 769 mAh g −1 at 5.0C after 200 cycles) and noticeable cycling performance (81.6% retention after 200 cycles). Our results build a new bridge between sulfur and carbon networks with multiple blocking effects for polysulfides, and provide references for construction of other high-performance sulfur cathodes.

Divergent actions of the pyrethroid insecticides S-bioallethrin, tefluthrin, and deltamethrin on rat Nav1.6 sodium channels

International Nuclear Information System (INIS)

Tan Jianguo; Soderlund, David M.

2010-01-01

We expressed rat Na v 1.6 sodium channels in combination with the rat β 1 and β 2 auxiliary subunits in Xenopus laevis oocytes and evaluated the effects of the pyrethroid insecticides S-bioallethrin, deltamethrin, and tefluthrin on expressed sodium currents using the two-electrode voltage clamp technique. S-Bioallethrin, a type I structure, produced transient modification evident in the induction of rapidly decaying sodium tail currents, weak resting modification (5.7% modification at 100 μM), and no further enhancement of modification upon repetitive activation by high-frequency trains of depolarizing pulses. By contrast deltamethrin, a type II structure, produced sodium tail currents that were ∼ 9-fold more persistent than those caused by S-bioallethrin, barely detectable resting modification (2.5% modification at 100 μM), and 3.7-fold enhancement of modification upon repetitive activation. Tefluthrin, a type I structure with high mammalian toxicity, exhibited properties intermediate between S-bioallethrin and deltamethrin: intermediate tail current decay kinetics, much greater resting modification (14.1% at 100 μM), and 2.8-fold enhancement of resting modification upon repetitive activation. Comparison of concentration-effect data showed that repetitive depolarization increased the potency of tefluthrin ∼ 15-fold and that tefluthrin was ∼ 10-fold more potent than deltamethrin as a use-dependent modifier of Na v 1.6 sodium channels. Concentration-effect data from parallel experiments with the rat Na v 1.2 sodium channel coexpressed with the rat β 1 and β 2 subunits in oocytes showed that the Na v 1.6 isoform was at least 15-fold more sensitive to tefluthrin and deltamethrin than the Na v 1.2 isoform. These results implicate sodium channels containing the Na v 1.6 isoform as potential targets for the central neurotoxic effects of pyrethroids.

Studies of pyrrole black electrodes as possible battery positive electrodes

Energy Technology Data Exchange (ETDEWEB)

Mengoli, G.; Musiani, M.M.; Fleischmann, M.; Pletcher, D.

1984-05-01

It is shown that a polypyrrole, pyrrole black, may be formed anodically in several aqueous acids. The polypyrrole film shows a redox couple at less positive potentials than that required to form the film and the charge associated with these reduction and oxidation processes together with their stabilty to cycling varies with the anion in solution and the potential where the polypyrrole is formed; over-oxidation of the film caused by taking its potential too positive has a particularly disadvantageous affect. In the acids HBr and HI, the polypyrrole films can act as a storage medium for Br/sub 2/ or I/sub 2/ so that they may be used as a substrate for a X/sub 2//X/sup -/ electrode. Such electrodes may be charge/discharge cycled and the pyrrole/Br/sub 2/ electrode shows promise as a battery positive electrode.

Tunable Reaction Potentials in Open Framework Nanoparticle Battery Electrodes for Grid-Scale Energy Storage

KAUST Repository

Wessells, Colin D.

2012-02-28

The electrical energy grid has a growing need for energy storage to address short-term transients, frequency regulation, and load leveling. Though electrochemical energy storage devices such as batteries offer an attractive solution, current commercial battery technology cannot provide adequate power, and cycle life, and energy efficiency at a sufficiently low cost. Copper hexacyanoferrate and nickel hexacyanoferrate, two open framework materials with the Prussian Blue structure, were recently shown to offer ultralong cycle life and high-rate performance when operated as battery electrodes in safe, inexpensive aqueous sodium ion and potassium ion electrolytes. In this report, we demonstrate that the reaction potential of copper-nickel alloy hexacyanoferrate nanoparticles may be tuned by controlling the ratio of copper to nickel in these materials. X-ray diffraction, TEM energy dispersive X-ray spectroscopy, and galvanostatic electrochemical cycling of copper-nickel hexacyanoferrate reveal that copper and nickel form a fully miscible solution at particular sites in the framework without perturbing the structure. This allows copper-nickel hexacyanoferrate to reversibly intercalate sodium and potassium ions for over 2000 cycles with capacity retentions of 100% and 91%, respectively. The ability to precisely tune the reaction potential of copper-nickel hexacyanoferrate without sacrificing cycle life will allow the development of full cells that utilize the entire electrochemical stability window of aqueous sodium and potassium ion electrolytes. © 2012 American Chemical Society.

PVC membrane, coated-wire, and carbon-paste ion-selective electrodes for potentiometric determination of galantamine hydrobromide in physiological fluids.

Science.gov (United States)

Abdel-Haleem, Fatehy M; Saad, Mohamed; Barhoum, Ahmed; Bechelany, Mikhael; Rizk, Mahmoud S

2018-08-01

We report on highly-sensitive ion-selective electrodes (ISEs) for potentiometric determining of galantamine hydrobromide (GB) in physiological fluids. Galantamine hydrobromide (GB) was selected for this study due to its previous medical importance for treating Alzheimer's disease. Three different types of ISEs were investigated: PVC membrane electrode (PVCE), carbon-paste electrode (CPE), and coated-wire electrode (CWE). In the construction of these electrodes, galantaminium-reineckate (GR) ion-pair was used as a sensing species for GB in solutions. The modified carbon-paste electrode (MCPE) was prepared using graphene oxide (MCPE-GO) and sodium tetrakis (trifluoromethyl) phenyl borate (MCPE-STFPB) as ion-exchanger. The potentiometric modified CPEs (MCPE-GO and MCPE-STFPB) show an improved performance in term of Nernstian slope, selectivity, response time, and response stability compared to the unmodified CPE. The prepared electrodes PVCE, CWE, CPE, MCPE-GO and MCPE-STFPB show Nernstian slopes of 59.9, 59.5, 58.1, 58.3 and 57.0 mV/conc. decade, and detection limits of 5.0 × 10 -6 , 6.3 × 10 -6 , 8.0 × 10 -6 , 6.0 × 10 -6 and 8.0 × 10 -6  mol L -1 , respectively. The prepared ISEs also show high selectivity against cations (i.e. Na + , K + , NH 4 + , Ca 2+ , Al 3+ , Fe 3+ ), amino acids (i.e. glycine, L-alanine alanine), and sugars (i.e. fructose, glucose, maltose, lactose). The prepared ISEs are applicable for determining GB in spiked serums, urines, and pharmaceutical preparations, using a standard addition and a direct potentiometric method. The fast response time (<10 s), long lifetime (1-5 weeks), reversibility and stability of the measured signals facilitate the application of these sensors for routine analysis of the real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Gas sensor with multiple internal reference electrodes and sensing electrodes

DEFF Research Database (Denmark)

2016-01-01

The invention relates to a potentiometric gas sensor, or potentiometric gas detection element, with multiple internal reference electrodes and multiple sensing electrodes for determining the concentrations of gas components in a gaseous mixture. The sensor for gas detection comprises: a solid...

A novel coated silver ketamine(I electrode for potentiometric determination of ketamine hydrochloride in ampoules and urine samples

Directory of Open Access Journals (Sweden)

Hazem M. Abu Shawish

2014-11-01

Full Text Available A new ketamine coated silver electrode (KCSE based on ketamine hydrochloride with sodium tetraphenylborate (KT-TPB as electroactive material has been described. The influence of membrane composition, type of solvent mediators, kind of electroactive materials and interfering ions on the sensor was investigated. The sensor displays Nernstian response of 55.8 ± 0.3 mV/decade over the concentration range of 2.5 × 10−6 to 1.0 × 10−2 M with limit of detection of 8.5 × 10−7 M. The coated wire electrode has short response time ∼8 s and it can be used in pH range of 2.6–6.4. The selective coefficients were determined in relation to several inorganic, organic ions, sugars and some common drug excipients. The KCSE electrode was successfully used for the determination of the ketamine content in ampoule and urine samples with satisfactory results. Statistical student’s t-test and F test showed insignificant systematic error between proposed and official methods.

Progress and recent developments in sodium, metal chloride batteries

International Nuclear Information System (INIS)

Ratnakumar, B.V.; Attia, A.I.; Halpert, G.

1991-01-01

A new class of rechargeable sodium batteries emerged in the last decade mainly due to the efforts in South Africa and the United Kingdom. These systems include solid transition metal chlorides in sodium tetrachloroaluminates as cathodes. Significant developments have been made on two systems, i.e., Na/NiCl 2 and Na/FeCl 2 ; high energy densities of the order of 130 Wh/Kg have been demonstrated at the cell level both with FeCl 2 and NiCl 2 cathodes. Long cycle life of over 2000 cycles was demonstrated with NiCl 2 , especially with a sulfur additive to the electrolyte to retain the sintered structure of the NiCl 2 electrode. Various environmental and safety tests have been successfully performed on the cells. Scale up efforts resulted in cells of 40 - 100 Ah, which were evaluated in an electric vehicle application. Additionally, it appears from a recent evaluation study carried out by European Space Agency on Na/NiCl 2 for GEO and LEO applications that energy densities of the order of 120 Wh/Kg and 100 Wh/Kg respectively at the cell level are feasible and long cycle lives (beyond 2800 cycles are possible). Several fundamental and developmental studies have been carried out at other laboratories aimed at understanding the reaction mechanisms, determining the kinetics and identifying various rate governing processes, and screening various other metal chlorides. Finally, the specific energies and especially the power densities projected for Na/FeCl 2 and Na/NiCl 2 systems based on alternate designs for beta alumina solid electrolyte, i.e., multiple tubes and flat plates are very attractive for electric vehicle and space applications. In this paper, the authors propose to present a detailed account of the developments made hither to as well as the key research issues being addressed in the sodium - metal chloride battery technology

Liquid sodium technology research

International Nuclear Information System (INIS)

Kim, W.C.; Lee, Y.W.; Nam, H.Y.; Chun, S.Y.; Kim, J.; Won, S.Y.

1982-01-01

This report describes the technology of impurity control and measurement of liquid sodium, problems associated with material degradation and change of heat transfer characteristics in liquid sodium, and the conceptual design of multipurpose sodium test loop. Discussion and the subsequent analysis are also made with regard to the test results for the sodium-H 2 0 reaction and its effects on the system. (author)

Development of a sodium ionization detector for sodium-to-gas leaks

International Nuclear Information System (INIS)

Swaminathan, K.; Elumalai, G.

1984-01-01

A sensitive sodium-to-gas leak detector has been indigenously developed for use in liquid metal cooled fast breeder reactor. The detector relies on the relative ease with which sodium vapour or its aerosols including its oxides and hydroxides can be thermally ionized compared with other possible constituents such as nitrogen, oxygen, water vapour etc. in a carrier gas and is therefore called sodium ionization detector (SID). The ionization current is a measure of sodium concentration in the carrier gas sampled through the detector. Different sensor designs using platinum and rhodium as filament materials in varying sizes were constructed and their responses to different sodium aerosol concentrations in the carrier gas were investigated. Nitrogen was used as the carrier gas. Both the background current and speed of response were found to depend on the diameter of the filament. There was also a particular collector voltage which yielded maximum sensitivity of the detector. The sensor was therefore optimised considering influence of above factors and a detector has been built which demonstrates a sensitivity better than 0.3 nanogram of sodium per cubic centimetre of carrier gas for a signal to background ratio of 1:1. Its usefulness in detecting sodium fires in experimental area was also demonstrated. Currently efforts are under way to improve the life time of the filament used in the above detector. (author)

Handbook of reference electrodes

CERN Document Server

Inzelt, György; Scholz, Fritz

2013-01-01

Reference Electrodes are a crucial part of any electrochemical system, yet an up-to-date and comprehensive handbook is long overdue. Here, an experienced team of electrochemists provides an in-depth source of information and data for the proper choice and construction of reference electrodes. This includes all kinds of applications such as aqueous and non-aqueous solutions, ionic liquids, glass melts, solid electrolyte systems, and membrane electrodes. Advanced technologies such as miniaturized, conducting-polymer-based, screen-printed or disposable reference electrodes are also covered. Essen

A study on sodium-concrete reaction

Energy Technology Data Exchange (ETDEWEB)

Bae, Jae Heum; Min, Byong Hun [Suwon University, Suwon (Korea, Republic of)

1997-07-01

A small sodium-concrete reaction facility was designed, manufactured and installed. this facility has been operated under inert gas(N{sub 2}) with different experimental variables such as sodium injection temperature, injection amount of sodium, aging period of concrete, sodium reservoir temperature. As a result, it was found that sodium injection temperature and injected amount of sodium has little effect on sodium-concrete reaction. However, sodium reservoir temperature and aging period of concrete has relatively high impact on sodium-concrete reaction. Sodium-concrete reaction model has also been developed and compared with experimental results. (Author) 51 refs., 16 tabs., 64 figs.

Dietary sodium

DEFF Research Database (Denmark)

Graudal, Niels

2015-01-01

The 2013 Institute of Medicine (IOM) report "Sodium Intake in Populations: Assessment of Evidence" did not support the current recommendations of the IOM and the American Heart Association (AHA) to reduce daily dietary sodium intake to below 2,300 mg. The report concluded that the population...

Lithium-aluminum-magnesium electrode composition

Science.gov (United States)

Melendres, Carlos A.; Siegel, Stanley

1978-01-01

A negative electrode composition is presented for use in a secondary, high-temperature electrochemical cell. The cell also includes a molten salt electrolyte of alkali metal halides or alkaline earth metal halides and a positive electrode including a chalcogen or a metal chalcogenide as the active electrode material. The negative electrode composition includes up to 50 atom percent lithium as the active electrode constituent and a magnesium-aluminum alloy as a structural matrix. Various binary and ternary intermetallic phases of lithium, magnesium, and aluminum are formed but the electrode composition in both its charged and discharged state remains substantially free of the alpha lithium-aluminum phase and exhibits good structural integrity.

Hollow Carbon Nanofiber-Encapsulated Sulfur Cathodes for High Specific Capacity Rechargeable Lithium Batteries

KAUST Repository

Zheng, Guangyuan

2011-10-12

Sulfur has a high specific capacity of 1673 mAh/g as lithium battery cathodes, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a hollow carbon nanofiber-encapsulated sulfur cathode for effective trapping of polysulfides and demonstrate experimentally high specific capacity and excellent electrochemical cycling of the cells. The hollow carbon nanofiber arrays were fabricated using anodic aluminum oxide (AAO) templates, through thermal carbonization of polystyrene. The AAO template also facilitates sulfur infusion into the hollow fibers and prevents sulfur from coating onto the exterior carbon wall. The high aspect ratio of the carbon nanofibers provides an ideal structure for trapping polysulfides, and the thin carbon wall allows rapid transport of lithium ions. The small dimension of these nanofibers provides a large surface area per unit mass for Li2S deposition during cycling and reduces pulverization of electrode materials due to volumetric expansion. A high specific capacity of about 730 mAh/g was observed at C/5 rate after 150 cycles of charge/discharge. The introduction of LiNO3 additive to the electrolyte was shown to improve the Coulombic efficiency to over 99% at C/5. The results show that the hollow carbon nanofiber-encapsulated sulfur structure could be a promising cathode design for rechargeable Li/S batteries with high specific energy. © 2011 American Chemical Society.

Preliminary Plugging tests in Narrow Sodium Channels by Sodium and Carbon Dioxide reaction

Energy Technology Data Exchange (ETDEWEB)

Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

This report is on the investigation of the physical/chemical phenomena that a slow loss of CO{sub 2} inventory into sodium after the sodium-CO{sub 2} boundary failure in PCHEs in realistic operating conditions. The first phenomenon is potential channel plugging inside the narrow PCHE channel. Unlike a conventional shell and- tube type HXs, failures in a PCHE are expected to be small cracks. If the faulted channel is blocked, it may have a positive function for plant safety because the pressure boundary would automatically recover due to this self-plugging. The other one is damage propagation on pressure boundary, which is referred to as potential wastage with combined corrosion/erosion effect. Physical/chemical phenomena that a slow loss of CO{sub 2} inventory into sodium after the sodium-CO{sub 2} boundary failure in printed circuit heat exchangers (PCHEs) were investigated. Our preliminary experimental results of plugging show that sodium flow immediately stopped as CO{sub 2} was injected through the nozzle at 300-400 .deg. C in 3 mm sodium channels, whereas sodium flow stopped about 60 min after CO{sub 2} injection in 5 mm sodium channels.

A Simple Hydrogen Electrode

Science.gov (United States)

Eggen, Per-Odd

2009-01-01

This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

Co9 S8 /Co as a High-Performance Anode for Sodium-Ion Batteries with an Ether-Based Electrolyte.

Science.gov (United States)

Zhao, Yingying; Pang, Qiang; Wei, Yingjin; Wei, Luyao; Ju, Yanming; Zou, Bo; Gao, Yu; Chen, Gang

2017-12-08

Co 9 S 8 has been regarded as a desirable anode material for sodium-ion batteries because of its high theoretical capacity. In this study, a Co 9 S 8 anode material containing 5.5 wt % Co (Co 9 S 8 /Co) was prepared by a solid-state reaction. The electrochemical properties of the material were studied in carbonate and ether-based electrolytes (EBE). The results showed that the material had a longer cycle life and better rate capability in EBE. This excellent electrochemical performance was attributed to a low apparent activation energy and a low overpotential for Na deposition in EBE, which improved the electrode kinetic properties. Furthermore, EBE suppressed side reactions of the electrode and electrolyte, which avoided the formation of a solid electrolyte interphase film. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ion-selective electrode reviews

CERN Document Server

Thomas, J D R

1982-01-01

Ion-Selective Electrode Reviews, Volume 3, provides a review of articles on ion-selective electrodes (ISEs). The volume begins with an article on methods based on titration procedures for surfactant analysis, which have been developed for discrete batch operation and for continuous AutoAnalyser use. Separate chapters deal with detection limits of ion-selective electrodes; the possibility of using inorganic ion-exchange materials as ion-sensors; and the effect of solvent on potentials of cells with ion-selective electrodes. Also included is a chapter on advances in calibration procedures, the d

Corrosion behaviors of ceramics against liquid sodium. Sodium corrosion characteristics of sintering additives

International Nuclear Information System (INIS)

Tachi, Yoshiaki; Kano, Shigeki; Hirakawa, Yasushi; Yoshida, Eiichi

1998-01-01

It has been progressed as the Frontier Materials Research to research and develop ceramics to apply for several components of fast breeder reactor using liquid sodium as coolant instead of metallic materials. Grain boundary of ceramics has peculiar properties compared with matrix because most of ceramics are produced by hardening and firing their raw powders. Some previous researchers indicated that ceramics were mainly corroded at grain boundaries by liquid sodium, and ceramics could not be used under corrosive environment. Thus, it is the most important for the usage of ceramics in liquid sodium to improve corrosion resistance of grain boundaries. In order to develop the advanced ceramics having good sodium corrosion resistance among fine ceramics, which have recently been progressed in quality and characteristics remarkably, sodium corrosion behaviors of typical sintering additives such as MgO, Y 2 O 3 and AlN etc. have been examined and evaluated. As a result, the followings have been clarified and some useful knowledge about developing advanced ceramics having good corrosion resistance against liquid sodium has been obtained. (1) Sodium corrosion behavior of MgO depended on Si content. Samples containing large amount of Si were corroded severely by liquid sodium, whereas others with low Si contents showed good corrosion resistance. (2) Both Y 2 O 3 and AlN, which contained little Si, showed good sodium corrosion resistance. (3) MgO, Y 2 O 3 and AlN are thought to be corroded by liquid sodium, if they contain some SiO 2 . Therefore, in order to improve sodium corrosion resistance, it is very important for these ceramics to prevent the contamination of matrix with SiO 2 through purity control of their raw powders. (author)

Sodium waste technology: A summary report

International Nuclear Information System (INIS)

Abrams, C.S.; Witbeck, L.C.

1987-01-01

The Sodium Waste Technology (SWT) Program was established to resolve long-standing issues regarding disposal of sodium-bearing waste and equipment. Comprehensive SWT research programs investigated a variety of approaches for either removing sodium from sodium-bearing items, or disposal of items containing sodium residuals. The most successful of these programs was the design, test, and the production operation of the Sodium Process Demonstration Facility at ANL-W. The technology used was a series of melt-drain-evaporate operations to remove nonradioactive sodium from sodium-bearing items and then converting the sodium to storable compounds

Analysis of oxidation of self-baking electrodes (Soederberg electrodes) by means of three-dimensional model

Science.gov (United States)

Pashnin, S. V.

2017-10-01

The paper presents the methodology and results of the development of the temperature dependence of the oxidation speed of the self-baking electrode (Soederberg Electrodes) in the ore-thermal furnaces. For the study of oxidation, the working ends of the self-baking electrodes, which were taken out from the ore-thermal furnaces after their scabbings, were used. The temperature of the electrode surface by its height was calculated with the help of the mathematical model of heat work of self-baking electrode. The comparison of electrode surface temperatures with the speed of oxidation of the electrode allowed one to obtain the temperature dependency of the oxidation of the lateral electrode surface. Comparison of the experimental data, obtained in the laboratory by various authors, showed their qualitative coincidence with results of calculations of the oxidation rate presented in this article. With the help of the mathematical model of temperatures fields of electrode, the calculations of the sizes of the cracks, appearing after burnout ribs, were performed. Calculations showed that the sizes of the cracks after the ribs burnout, calculated by means of the obtained temperature dependence, coincide with the experimental data with sufficient accuracy.

Manufacturing process and electrode properties of palladium-electroded ionic polymer–metal composite

International Nuclear Information System (INIS)

Chang, Longfei; Chen, Hualing; Zhu, Zicai; Li, Bo

2012-01-01

This paper primarily focuses on the manufacturing process of palladium-electroded ionic polymer–metal composite (IPMC). First, according to the special properties of Pd, many experiments were done to determine several specific procedures, including the addition of a reducing agent and the time consumed. Subsequently, the effects of the core manufacturing steps on the electrode morphology were revealed by scanning electron microscopy studies of 22 IPMC samples treated with different combinations of manufacturing steps. Finally, the effects of electrode characteristics on the electromechanical properties, including the sheet resistivity, the elastic modulus and the electro-active performance, of IPMCs were evaluated experimentally and analyzed according to the electrode morphology. (paper)

Time-dependent simulation of plasma and electrodes in high-intensity discharge lamps with different electrode shapes

CERN Document Server

Flesch, P

2003-01-01

The subject of this paper is the modelling of d.c. and a.c. high-intensity Hg-discharge lamps with differently shaped electrodes. Different arc attachments on the electrodes are studied and insight for the development of new electrodes is gained. The model includes the entire discharge plasma (plasma column, hot plasma spots in front of electrodes, near-electrode non-LTE-plasma) as well as anode and cathode. No subdivision of the discharge space into different regions is necessary (like space charge layer, ionization zone, plasma column). This is achieved by using a differential equation for a non-LTE electrical conductivity which is applicable for local thermal equilibrium (LTE-)regions as well as for non-LTE plasma regions close to the electrodes in a high pressure plasma. Modelling results for a 0.6 MPa mercury discharge considering six different electrode shapes (anode and cathode) are presented and compared with experimental results. The electrodes have different diameters and different electrode tips, s...

Robust high temperature oxygen sensor electrodes

DEFF Research Database (Denmark)

Lund, Anders

Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode...... materials as candidates for robust oxygen sensor electrodes. The present work focuses on characterising the electrochemical properties of a few electrode materials to understand which oxygen electrode processes are limiting for the response time of the sensor electrode. Three types of porous platinum......-Dansensor. The electrochemical properties of the electrodes were characterised by electrochemical impedance spectroscopy (EIS), and the structures were characterised by x-ray diffraction and electron microscopy. At an oxygen partial pressures of 0.2 bar, the response time of the sensor electrode was determined by oxygen...

Parametric study of sodium aerosols in the cover-gas space of sodium-cooled reactors

International Nuclear Information System (INIS)

Sheth, A.

1975-03-01

A mathematical model has been developed to describe the behavior of sodium aerosols in the cover-gas space of a sodium-cooled reactor. A review of the literature was first made to examine methods of aerosol generation, mathematical expressions representing aerosol behavior, and pertinent experimental investigations of sodium aerosols. In the development of the model, some terms were derived from basic principles and other terms were estimated from available correlations. The model was simulated on a computer, and important parameters were studied to determine their effects on the overall behavior of sodium aerosols. The parameters studied were sodium pool temperature, source and initial size of particles, film thickness at the sodium pool/cover gas interface, wall plating parameters, cover-gas flow rate, and type of cover gas (argon and helium). The model satisfactorily describes the behavior of sodium aerosol in argon, but not in helium. Possible reasons are given for the failure of the model with helium, and further experimental work is recommended. The mathematical model, with appropriate modifications to describe the behavior of sodium aerosols in helium, would be very useful in designing traps to remove aerosols from the cover gas of sodium-cooled reactors. (U.S.)

A Simple Quantitative Synthesis: Sodium Chloride from Sodium Carbonate.

Science.gov (United States)

Gold, Marvin

1988-01-01

Describes a simple laboratory procedure for changing sodium carbonate into sodium chloride by adding concentrated HCl to cause the reaction and then evaporating the water. Claims a good stoichiometric yield can be obtained in one three-hour lab period. Suggests using fume hood for the reaction. (ML)

Voltammetric behavior of sedative drug midazolam at glassy carbon electrode in solubilized systems.

Science.gov (United States)

Jain, Rajeev; Yadav, Rajeev Kumar

2012-04-01

Redox behavior of midazolam was studied at a glassy carbon electrode in various buffer systems, supporting electrolytes and pH using differential pulse, square-wave and cyclic voltammetry. Based on its reduction behavior, a direct differential pulse voltammetric method has been developed and validated for the determination of midazolam in parenteral dosage. Three well-defined peaks were observed in 0.1% SLS, Britton-Robinson (BR) buffer of pH 2.5. The effect of surfactants like sodium lauryl sulfate (SLS), cetyl trimethyl ammonium bromide (CTAB) and Tween 20 was studied. Among these surfactants SLS showed significant enhancement in reduction peak. The cathodic peak currents were directly proportional to the concentration of midazolam with correlation coefficient of 0.99.

Electrodeposition of polypyrrole on aluminium in the presence of sodium bis(2-ethylhexyl) sulfosuccinate

International Nuclear Information System (INIS)

Lehr, I.L.; Saidman, S.B.

2006-01-01

Stable and adherent polypyrrole films have been successfully electrodeposited onto aluminium electrode over a wide solution pH interval by using sodium bis(2-ethylhexyl) sulfosuccinate as dopant. The redox behaviour of the deposited coating was studied by cyclic voltammetry in different electrolytes and the corrosion protection properties were examined in chloride solution by polarisation studies and open circuit measurements. The polymer film was characterised by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The obtained results are explained considering the surfactant remains entrapped into the polymer matrix. The coatings inhibit the oxidation of the aluminium substrate even on polarisation to high anodic potentials

Sensor employing internal reference electrode

DEFF Research Database (Denmark)

2013-01-01

The present invention concerns a novel internal reference electrode as well as a novel sensing electrode for an improved internal reference oxygen sensor and the sensor employing same.......The present invention concerns a novel internal reference electrode as well as a novel sensing electrode for an improved internal reference oxygen sensor and the sensor employing same....

Microbial electrode sensor for alcohols

Energy Technology Data Exchange (ETDEWEB)

Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

1979-10-01

A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

Chemical Adsorption and Physical Confinement of Polysulfides with the Janus-faced Interlayer for High-performance Lithium-Sulfur Batteries.

Science.gov (United States)

Chiochan, Poramane; Kaewruang, Siriroong; Phattharasupakun, Nutthaphon; Wutthiprom, Juthaporn; Maihom, Thana; Limtrakul, Jumras; Nagarkar, Sanjog; Horike, Satoshi; Sawangphruk, Montree

2017-12-18

We design the Janus-like interlayer with two different functional faces for suppressing the shuttle of soluble lithium polysulfides (LPSs) in lithium-sulfur batteries (LSBs). At the front face, the conductive functionalized carbon fiber paper (f-CFP) having oxygen-containing groups i.e., -OH and -COOH on its surface was placed face to face with the sulfur cathode serving as the first barrier accommodating the volume expansion during cycling process and the oxygen-containing groups can also adsorb the soluble LPSs via lithium bonds. At the back face, a crystalline coordination network of [Zn(H 2 PO 4 ) 2 (TzH) 2 ] n (ZnPTz) was coated on the back side of f-CFP serving as the second barrier retarding the left LPSs passing through the front face via both physical confinement and chemical adsorption (i.e. Li bonding). The LSB using the Janus-like interlayer exhibits a high reversible discharge capacity of 1,416 mAh g -1 at 0.1C with a low capacity fading of 0.05% per cycle, 92% capacity retention after 200 cycles and ca. 100% coulombic efficiency. The fully charged LSB cell can practically supply electricity to a spinning motor with a nominal voltage of 3.0 V for 28 min demonstrating many potential applications.

Comparison Study of Voltammetric Behavior of Muscle Relaxant Dantrolene Sodium on Silver Solid Amalgam and Bismuth Film Electrodes

Czech Academy of Sciences Publication Activity Database

Šelešovská, R.; Martinková, P.; Štěpánková, M.; Navrátil, Tomáš; Chýlková, J.

2017-01-01

Roč. 2017, č. 2017 (2017), č. článku 3627428. ISSN 2090-8865 R&D Projects: GA ČR GA17-03868S Institutional support: RVO:61388955 Keywords : performance liquid-chromatography * differential-pulse polarography * anodic-stripping voltammetry * screen-printed electrodes * organic-compounds Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 1.801, year: 2016

Comparison Study of Voltammetric Behavior of Muscle Relaxant Dantrolene Sodium on Silver Solid Amalgam and Bismuth Film Electrodes

Czech Academy of Sciences Publication Activity Database

Šelešovská, R.; Martinková, P.; Štěpánková, M.; Navrátil, Tomáš; Chýlková, J.

2017-01-01

Roč. 2017, č. 2017 (2017), č. článku 3627428. ISSN 2090-8865 R&D Projects: GA ČR GA17-03868S Institutional support: RVO:61388955 Keywords : performance liquid - chromatography * differential-pulse polarography * anodic-stripping voltammetry * screen-printed electrodes * organic-compounds Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 1.801, year: 2016

Effect of Particle Size on Electrode Potential and Thermodynamics of Nanoparticles Electrode in Theory and Experiment

International Nuclear Information System (INIS)

Yunfeng, Yang; Yongqiang, Xue; Zixiang, Cui; Miaozhi, Zhao

2014-01-01

The particle size of electrode materials has a significant influence on the standard electrode potential and the thermodynamic properties of electrode reactions. In this paper, the size-dependent electrochemical thermodynamics has been theoretically investigated and successfully deduced electrochemical thermodynamics equations for nanoparticles electrode. At the same time, the electrode potential and thermodynamical properties of Ag 2 O/Ag nanoparticles electrode constructed by the solid and spherical Ag 2 O nanoparticles with different sizes further testified that the particle size of nanoparticles has a significant effect on electrochemical thermodynamics. The results show that the electrode potential depends on that of the smallest nanoparticle in a nanoparticles electrode which consisted of different particle sizes of nano-Ag 2 O. When the size of Ag 2 O nanoparticles reduces, the standard electrode potentials and the equilibrium constants of the corresponding electrode reactions increase, and the temperature coefficient, the mole Gibbs energy change, the mole enthalpy change and the mole entropy change decrease. Moreover, these physical quantities are all linearly related with the reciprocal of average particle size (r > 10 nm). The experimental regularities coincide with the theoretical equations

Pitch ranking, electrode discrimination, and physiological spread-of-excitation using Cochlear's dual-electrode mode.

Science.gov (United States)

Goehring, Jenny L; Neff, Donna L; Baudhuin, Jacquelyn L; Hughes, Michelle L

2014-08-01

This study compared pitch ranking, electrode discrimination, and electrically evoked compound action potential (ECAP) spatial excitation patterns for adjacent physical electrodes (PEs) and the corresponding dual electrodes (DEs) for newer-generation Cochlear devices (Cochlear Ltd., Macquarie, New South Wales, Australia). The first goal was to determine whether pitch ranking and electrode discrimination yield similar outcomes for PEs and DEs. The second goal was to determine if the amount of spatial separation among ECAP excitation patterns (separation index, Σ) between adjacent PEs and the PE-DE pairs can predict performance on the psychophysical tasks. Using non-adaptive procedures, 13 subjects completed pitch ranking and electrode discrimination for adjacent PEs and the corresponding PE-DE pairs (DE versus each flanking PE) from the basal, middle, and apical electrode regions. Analysis of d' scores indicated that pitch-ranking and electrode-discrimination scores were not significantly different, but rather produced similar levels of performance. As expected, accuracy was significantly better for the PE-PE comparison than either PE-DE comparison. Correlations of the psychophysical versus ECAP Σ measures were positive; however, not all test/region correlations were significant across the array. Thus, the ECAP separation index is not sensitive enough to predict performance on behavioral tasks of pitch ranking or electrode discrimination for adjacent PEs or corresponding DEs.

Hidden Sodium

Centers for Disease Control (CDC) Podcasts

2013-03-04

In this podcast, learn about reducing sodium intake by knowing what to eat and the main sources of sodium in the diet. It's important for a healthy lifestyle.  Created: 3/4/2013 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/4/2013.

[Sodium intake during pregnancy].

Science.gov (United States)

Delemarre, F M; Franx, A; Knuist, M; Steegers, E A

1999-10-23

International studies have yielded contradictory results on efficacy of a sodium-restricted diet during pregnancy in preventing and curing hypertension of pregnancy. In the Netherlands three studies have been performed to investigate the value of dietary sodium restriction in pregnancy; they concerned epidemiology, prevention and treatment. Midwives often prescribed this dietary intervention. Urinary sodium excretion was not related to blood pressure changes in pregnancy. Dietary sodium restriction from the third month of pregnancy onwards did not reduce the incidence of pregnancy-induced hypertension. Maternal side effects were a decreased intake of nutrients, decreased maternal weight gain, lowered plasma volume and stimulation of the renin-angiotensin-aldosterone system. A dietary sodium restriction in women with early symptoms of pregnancy-induced hypertension showed no therapeutic effect on blood pressure. There is no place for dietary sodium restriction in the prevention or treatment of hypertension in pregnancy.

Review of the sodium fire experiments including sodium-concrete-reactions and summary of the results

International Nuclear Information System (INIS)

Cherdron, W.

1996-01-01

In the technical and design concept of containment systems of sodium cooled breeder reactors it has to be considered, that leakages in sodium pipes lead to sodium fires. The temperature and pressure rise caused by sodium fires makes it indispensable to analyse these accidents to be able to assess the safety of the whole system. Generally sodium leakages may lead to three different types of fires with different consequences. The main influences are the geometry of the leakage, shape, size, location, and the sodium conditions, such as temperature, flow rate and velocity. It must be also considered the reaction of sodium with surfaces like concrete. The paper gives an overview over all the sodium fire experiments performed in the FAUNA-facility (220 m 3 ) of the Forschungszentrum Karlsruhe in the years 1979 to 1993. The experimental program started with the investigation of pool fires on burning areas between 2 and 12 m 2 with up to 500 kg of Sodium. The experiments had been continued with 3 combined fires and 40 experiments on spray fires. 7 experiments on sodium-concrete reactions completed the program. (author)

Sodium fires and its extinguishment

International Nuclear Information System (INIS)

Mikhedov, V.G.

1979-01-01

The fire safety problems of NPP with sodium coolants in USSR are presented. The design of sodium reactors is made with premises with sodium coolants being hermetic and filled with nitrogen. Some engineering solutions of fire safety including design, elaboration and choice of construction and protection materials are presented. Some theoretical aspects of sodium burning are presented as well as methods of sodium fire extinguishing methods including the use of powder

Cr{sub 2}O{sub 5} as new cathode for rechargeable sodium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Feng, Xu-Yong; Chien, Po-Hsiu; Rose, Alyssa M.; Zheng, Jin [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Hung, Ivan; Gan, Zhehong [Centre of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310 (United States); Hu, Yan-Yan, E-mail: hu@chem.fsu.edu [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Centre of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310 (United States)

2016-10-15

Chromium oxide, Cr{sub 2}O{sub 5}, was synthesized by pyrolyzing CrO{sub 3} at 350 °C and employed as a new cathode in rechargeable sodium ion batteries. Cr{sub 2}O{sub 5}/Na rechargeable batteries delivered high specific capacities up to 310 mAh/g at a current density of C/16 (or 20 mA/g). High-resolution solid-state {sup 23}Na NMR both qualitatively and quantitatively revealed the reversible intercalation of Na ions into the bulk electrode and participation of Na ions in the formation of the solid-electrolyte interphase largely at low potentials. Amorphization of the electrode structure occurred during the first discharge revealed by both NMR and X-ray diffraction data. CrO{sub 3}-catalyzed electrolyte degradation and loss in electronic conductivity led to gradual capacity fading. The specific capacity stabilized at >120 mAh/g after 50 charge-discharge cycles. Further improvement in electrochemical performance is possible via electrode surface modification, polymer binder incorporation, or designs of new morphologies. - Graphical abstract: Electrochemical profile of a Cr{sub 2}O{sub 5}/Na battery cell and high-resolution solid-state {sup 23}Na MAS NMR spectrum of a Cr{sub 2}O{sub 5} electrode discharged to 2 V. - Highlights: • Cr{sub 2}O{sub 5} was synthesized and used as a new cathode in rechargeable Na ion batteries. • A high capacity of 310 mAh/g and an energy density of 564 Wh/kg were achieved. • High-resolution solid-state {sup 23}Na NMR was employed to follow the reaction mechanisms.

Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments

Energy Technology Data Exchange (ETDEWEB)

Pain, H. J.; Fearn, D. G.; Distefano, E. [Imperial College. London (United Kingdom)

1966-10-15

(a) Electrode conduction processes have been investigated using a plasma produced in an electromagnetic shock tube operating with argon at 70 {mu}mHg pressure. Complete voltage-current characteristics were obtained by the variation of load and applied voltage. These indicated the existence of two conduction regimes with a complex transition region. In the first regime the current, controlled by ion mobility, rose linearly with voltage to saturate between 10 mA and 1 A depending on conditions. Electrode contamination was significant. The second regime involved large currents controlled by electron mobility and emission from the cathode. The current again increased linearly with voltage and reached 200 A. Observation of induced voltages in transverse magnetic fields and of plasma deceleration in non-uniform fields showed that in the electromagnetic shock tube the plasma was heated predominantly by the driver discharge. Its conductivity was calculated using properties measured by a Langmuir double probe. In both regimes the plasma conductivity was also found from the gradient of the voltage current characteristics using experimental electric field fringing factors and the experimental values were compared with theory. (b) Larger-scale experiments used a combustion-driven shock tube where argon plasma flow, magnetic field and induced current flow were mutually orthogonal. The supersonic flow velocity and thermodynamic parameters of the plasma were accurately known. The electrode channel consisted of a segmented system of 12 electrode pairs with an electrode insulator ratio ranging from 1 to 21, with electrode plus insulator length remaining constant, and with maximum Hall parameter values of unity. Different electrode load combinations (Faraday and Hall generators) have been studied in measuring the power generated and the flow of longitudinal currents between adjacent electrodes. A maximum power of 0,8 MW was obtained, the power output decreasing inversely with the

Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments

International Nuclear Information System (INIS)

Pain, H.J.; Fearn, D.G.; Distefano, E.

1966-01-01

(a) Electrode conduction processes have been investigated using a plasma produced in an electromagnetic shock tube operating with argon at 70 μmHg pressure. Complete voltage-current characteristics were obtained by the variation of load and applied voltage. These indicated the existence of two conduction regimes with a complex transition region. In the first regime the current, controlled by ion mobility, rose linearly with voltage to saturate between 10 mA and 1 A depending on conditions. Electrode contamination was significant. The second regime involved large currents controlled by electron mobility and emission from the cathode. The current again increased linearly with voltage and reached 200 A. Observation of induced voltages in transverse magnetic fields and of plasma deceleration in non-uniform fields showed that in the electromagnetic shock tube the plasma was heated predominantly by the driver discharge. Its conductivity was calculated using properties measured by a Langmuir double probe. In both regimes the plasma conductivity was also found from the gradient of the voltage current characteristics using experimental electric field fringing factors and the experimental values were compared with theory. (b) Larger-scale experiments used a combustion-driven shock tube where argon plasma flow, magnetic field and induced current flow were mutually orthogonal. The supersonic flow velocity and thermodynamic parameters of the plasma were accurately known. The electrode channel consisted of a segmented system of 12 electrode pairs with an electrode insulator ratio ranging from 1 to 21, with electrode plus insulator length remaining constant, and with maximum Hall parameter values of unity. Different electrode load combinations (Faraday and Hall generators) have been studied in measuring the power generated and the flow of longitudinal currents between adjacent electrodes. A maximum power of 0,8 MW was obtained, the power output decreasing inversely with the

All-solid-state carbonate-selective electrode based on screen-printed carbon paste electrode