Lisicon Glass-Ceramics Mediated Catalysis of Oxygen Reduction

DTIC Science & Technology

2011-06-01

submitted January 19, 2011; revised manuscript received February 23, 2011. Published March 25, 2011. The Lisicon (lithium super ionic conductor) glass...ceramics is a polycrystalline analogue of Nasicon (sodium super ionic conductor) structure. The general class of Nasicon structures consists of two...with a heating rate of 5C=min. In the BET technique a dry specimen was evacuated of all gases and cooled down to 77 K, liquid nitrogen temperature

Insight into fast ion migration kinetics of a new hybrid single Li-ion conductor based on aluminate complexes for solid-state Li-ion batteries.

PubMed

Feng, Yancong; Tan, Rui; Zhao, Yan; Gao, Rongtan; Yang, Luyi; Yang, Jinlong; Li, Hao; Zhou, Guofu; Chen, Haibiao; Pan, Feng

2018-03-29

A novel hybrid single Li-ion conductor (SLIC) for a Li-ion solid electrolyte was prepared by mixing aluminate complexes-polyethylene glycol (LiAl-PEG) and polyethylene oxide (PEO) for solid-state Li-ion batteries. The LiAl-PEG/PEO blend possesses high thermal stability and electrochemical stability with an oxidation decomposition voltage up to 4.8 V. Notably, this hybrid SLIC exhibits not only excellent Li-ion migration kinetics, but also good ionic conductivity as high as 4.0 × 10-5 and 2.6 × 10-4 S cm-1 at 30 and 100 °C, respectively, which is much higher than previously reported SLICs. Importantly, by the combination of molecular dynamics simulations and experiment measurements, the mechanisms of Li-ion migration across the SLIC (LiAl-PEG), the salt-in-polymer (LiClO4/PEO) and the optimized SLIC (LiAl-PEG/PEO) were systematically investigated for the first time. The new hopping transport mechanism was verified for the SLIC system at the nanoscale. As for the hybrid SLIC, PEO chains enhance the segmental mobility of the ether-chains bonded with Al atoms, improve the ionicity, and provide extra ionic paths for Li transfer, resulting in the optimized Li-ion migration kinetics of LiAl-PEG/PEO.

A new percolation model for composite solid electrolytes and dispersed ionic conductors

NASA Astrophysics Data System (ADS)

Risyad Hasyim, Muhammad; Lanagan, Michael T.

2018-02-01

Composite solid electrolytes (CSEs) including conductor/insulator composites known as dispersed ionic conductors (DICs) have motivated the development of novel percolation models that describe their conductivity. Despite the long history, existing models lack in one or more key areas: (1) rigorous foundation for their physical theory, (2) explanation for non-universal conductor-insulator transition, (3) classification of DICs, and (4) extension to frequency-domain. This work describes a frequency-domain effective medium approximation (EMA) of a bond percolation model for CSEs. The EMA is derived entirely from Maxwell’s equations and contains basic microstructure parameters. The model was applied successfully to several composite systems from literature. Simulations and fitting of literature data address these key areas and illustrate the interplay between space charge layer properties and bulk microstructure.

STUDY ON LITHIUM FAST ION CONDUCTORS OF Li2O SiO2 V2O5 SYSTEM

NASA Astrophysics Data System (ADS)

Huang, Geng; Wang, Wenji

Fast ion conductors of Li2O SiO2 V2O5 system have been prepared by using Li2O, SiO2 and V2O5 as starting materials. The optimal ratio of starting materials was designed by Uniform Design. The conductivities of both electric and ionic were investigated. The highest ion conductivity is 1.5 × 10-4S/cm at ambient temperature for the above lithium fast ion conductor system, the electronic conductivity is 4 orders of magnitude lower than the ionic conductivity.

Nonlinear space charge dynamics in mixed ionic-electronic conductors: Resistive switching and ferroelectric-like hysteresis of electromechanical response

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

Morozovska, Anna N.; Morozovsky, Nicholas V.; Eliseev, Eugene A.

We performed self-consistent modelling of nonlinear electrotransport and electromechanical response of thin films of mixed ionic-electronic conductors (MIEC) allowing for steric effects of mobile charged defects (ions, protons, or vacancies), electron degeneration, and Vegard stresses. We establish correlations between the features of the nonlinear space-charge dynamics, current-voltage, and bending-voltage curves for different types of the film electrodes. A pronounced ferroelectric-like hysteresis of the bending-voltage loops and current maxima on the double hysteresis current-voltage loops appear for the electron-transport electrodes. The double hysteresis loop with pronounced humps indicates a memristor-type resistive switching. The switching occurs due to the strong nonlinear couplingmore » between the electronic and ionic subsystems. A sharp meta-stable maximum of the electron density appears near one open electrode and moves to another one during the periodic change of applied voltage. Our results can explain the nonlinear nature and correlation of electrical and mechanical memory effects in thin MIEC films. The analytical expression proving that the electrically induced bending of MIEC films can be detected by interferometric methods is derived.« less

Coherency strain and its effect on ionic conductivity and diffusion in solid electrolytes--an improved model for nanocrystalline thin films and a review of experimental data.

PubMed

Korte, C; Keppner, J; Peters, A; Schichtel, N; Aydin, H; Janek, J

2014-11-28

A phenomenological and analytical model for the influence of strain effects on atomic transport in columnar thin films is presented. A model system consisting of two types of crystalline thin films with coherent interfaces is assumed. Biaxial mechanical strain ε0 is caused by lattice misfit of the two phases. The conjoined films consist of columnar crystallites with a small diameter l. Strain relaxation by local elastic deformation, parallel to the hetero-interface, is possible along the columnar grain boundaries. The spatial extent δ0 of the strained hetero-interface regions can be calculated, assuming an exponential decay of the deformation-forces. The effect of the strain field on the local ionic transport in a thin film is then calculated by using the thermodynamic relation between (isostatic) pressure and free activation enthalpy ΔG(#). An expression describing the total ionic transport relative to bulk transport of a thin film or a multilayer as a function of the layer thickness is obtained as an integral average over strained and unstrained regions. The expression depends only on known material constants such as Young modulus Y, Poisson ratio ν and activation volume ΔV(#), which can be combined as dimensionless parameters. The model is successfully used to describe own experimental data from conductivity and diffusion studies. In the second part of the paper a comprehensive literature overview of experimental studies on (fast) ion transport in thin films and multilayers along solid-solid hetero-interfaces is presented. By comparing and reviewing the data the observed interface effects can be classified into three groups: (i) transport along interfaces between extrinsic ionic conductors (and insulator), (ii) transport along an open surface of an extrinsic ionic conductor and (iii) transport along interfaces between intrinsic ionic conductors. The observed effects in these groups differ by about five orders of magnitude in a very consistent way. The modified interface transport in group (i) is most probably caused by strain effects, misfit dislocations or disordered transition regions.

Enhancing grain boundary ionic conductivity in mixed ionic–electronic conductors

DOE PAGES

Lin, Ye; Fang, Shumin; Su, Dong; ...

2015-04-10

Mixed ionic–electronic conductors are widely used in devices for energy conversion and storage. Grain boundaries in these materials have nanoscale spatial dimensions, which can generate substantial resistance to ionic transport due to dopant segregation. Here, we report the concept of targeted phase formation in a Ce 0.8Gd 0.2O 2₋δ–CoFe 2O 4 composite that serves to enhance the grain boundary ionic conductivity. Using transmission electron microscopy and spectroscopy approaches, we probe the grain boundary charge distribution and chemical environments altered by the phase reaction between the two constituents. The formation of an emergent phase successfully avoids segregation of the Gd dopantmore » and depletion of oxygen vacancies at the Ce 0.8Gd 0.2O 2₋δ–Ce 0.8Gd 0.2O 2₋δ grain boundary. This results in superior grain boundary ionic conductivity as demonstrated by the enhanced oxygen permeation flux. Lastly, this work illustrates the control of mesoscale level transport properties in mixed ionic–electronic conductor composites through processing induced modifications of the grain boundary defect distribution.« less

Structural control of mixed ionic and electronic transport in conducting polymers

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

Rivnay, Jonathan; Inal, Sahika; Collins, Brian A.

Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate), PEDOT:PSS, has been utilized for over two decades as a stable, solution-processable hole conductor. While its hole transport properties have been the subject of intense investigation, recent work has turned to PEDOT:PSS as a mixed ionic/electronic conductor in applications including bioelectronics, energy storage and management, and soft robotics. Conducting polymers can efficiently transport both holes and ions when sufficiently hydrated, however, little is known about the role of morphology on mixed conduction. Here, we show that bulk ionic and electronic mobilities are simultaneously affected by processing-induced changes in nano- and meso-scale structure in PEDOT:PSS films. Wemore » quantify domain composition, and find that domain purification on addition of dispersion co-solvents limits ion mobility, even while electronic conductivity improves. We show that an optimal morphology allows for the balanced ionic and electronic transport that is critical for prototypical mixed conductor devices. As a result, these findings may pave the way for the rational design of polymeric materials and processing routes to enhance devices reliant on mixed conduction.« less

Enhancing grain boundary ionic conductivity in mixed ionic–electronic conductors

PubMed Central

Lin, Ye; Fang, Shumin; Su, Dong; Brinkman, Kyle S; Chen, Fanglin

2015-01-01

Mixed ionic–electronic conductors are widely used in devices for energy conversion and storage. Grain boundaries in these materials have nanoscale spatial dimensions, which can generate substantial resistance to ionic transport due to dopant segregation. Here, we report the concept of targeted phase formation in a Ce0.8Gd0.2O2−δ–CoFe2O4 composite that serves to enhance the grain boundary ionic conductivity. Using transmission electron microscopy and spectroscopy approaches, we probe the grain boundary charge distribution and chemical environments altered by the phase reaction between the two constituents. The formation of an emergent phase successfully avoids segregation of the Gd dopant and depletion of oxygen vacancies at the Ce0.8Gd0.2O2−δ–Ce0.8Gd0.2O2−δ grain boundary. This results in superior grain boundary ionic conductivity as demonstrated by the enhanced oxygen permeation flux. This work illustrates the control of mesoscale level transport properties in mixed ionic–electronic conductor composites through processing induced modifications of the grain boundary defect distribution. PMID:25857355

Enhancing grain boundary ionic conductivity in mixed ionic–electronic conductors

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

Lin, Ye; Fang, Shumin; Su, Dong

Mixed ionic–electronic conductors are widely used in devices for energy conversion and storage. Grain boundaries in these materials have nanoscale spatial dimensions, which can generate substantial resistance to ionic transport due to dopant segregation. Here, we report the concept of targeted phase formation in a Ce 0.8Gd 0.2O 2₋δ–CoFe 2O 4 composite that serves to enhance the grain boundary ionic conductivity. Using transmission electron microscopy and spectroscopy approaches, we probe the grain boundary charge distribution and chemical environments altered by the phase reaction between the two constituents. The formation of an emergent phase successfully avoids segregation of the Gd dopantmore » and depletion of oxygen vacancies at the Ce 0.8Gd 0.2O 2₋δ–Ce 0.8Gd 0.2O 2₋δ grain boundary. This results in superior grain boundary ionic conductivity as demonstrated by the enhanced oxygen permeation flux. Lastly, this work illustrates the control of mesoscale level transport properties in mixed ionic–electronic conductor composites through processing induced modifications of the grain boundary defect distribution.« less

Structural control of mixed ionic and electronic transport in conducting polymers

DOE PAGES

Rivnay, Jonathan; Inal, Sahika; Collins, Brian A.; ...

2016-04-19

Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate), PEDOT:PSS, has been utilized for over two decades as a stable, solution-processable hole conductor. While its hole transport properties have been the subject of intense investigation, recent work has turned to PEDOT:PSS as a mixed ionic/electronic conductor in applications including bioelectronics, energy storage and management, and soft robotics. Conducting polymers can efficiently transport both holes and ions when sufficiently hydrated, however, little is known about the role of morphology on mixed conduction. Here, we show that bulk ionic and electronic mobilities are simultaneously affected by processing-induced changes in nano- and meso-scale structure in PEDOT:PSS films. Wemore » quantify domain composition, and find that domain purification on addition of dispersion co-solvents limits ion mobility, even while electronic conductivity improves. We show that an optimal morphology allows for the balanced ionic and electronic transport that is critical for prototypical mixed conductor devices. As a result, these findings may pave the way for the rational design of polymeric materials and processing routes to enhance devices reliant on mixed conduction.« less

Atomistic interpretation of the ac-dc crossover frequency in crystalline and glassy ionic conductors

NASA Astrophysics Data System (ADS)

Marple, M. A. T.; Avila-Paredes, H.; Kim, S.; Sen, S.

2018-05-01

A comprehensive analysis of the ionic dynamics in a wide variety of crystalline and glassy ionic conductors, obtained in recent studies using a combination of electrochemical impedance and nuclear magnetic resonance spectroscopic techniques, is presented. These results demonstrate that the crossover frequency, between the frequency-independent dc conductivity and the frequency-dependent ac conductivity, corresponds to the time scale of "successful" diffusive hops of the mobile ions between the trapping sites in the structure. These inter-site hops are typically compound in nature and consist of several elementary hops in the intervening region between the neighboring trapping sites.

Atomistic interpretation of the ac-dc crossover frequency in crystalline and glassy ionic conductors.

PubMed

Marple, M A T; Avila-Paredes, H; Kim, S; Sen, S

2018-05-28

A comprehensive analysis of the ionic dynamics in a wide variety of crystalline and glassy ionic conductors, obtained in recent studies using a combination of electrochemical impedance and nuclear magnetic resonance spectroscopic techniques, is presented. These results demonstrate that the crossover frequency, between the frequency-independent dc conductivity and the frequency-dependent ac conductivity, corresponds to the time scale of "successful" diffusive hops of the mobile ions between the trapping sites in the structure. These inter-site hops are typically compound in nature and consist of several elementary hops in the intervening region between the neighboring trapping sites.

On the origin of high ionic conductivity in Na-doped SrSiO 3

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

Chien, Po-Hsiu; Jee, Youngseok; Huang, Chen

Understanding the local structure and ion dynamics is at the heart of ion conductor research. This paper reports on high-resolution solid-state 29Si, 23Na, and 17O NMR investigation of the structure, chemical composition, and ion dynamics of a newly discovered fast ion conductor, Na-doped SrSiO 3, which exhibited a much higher ionic conductivity than most of current oxide ion conductors. Quantitative analyses reveal that with a small dose (<10 mol%) of Na, the doped Na integrates into the SrSiO 3 structure to form Na xSr 1-xSiO 3-0.5x, and with >10 mol% Na doping, phase separation occurs, leading to the formation ofmore » an amorphous phase β-Na 2Si 2O 5 and a crystalline Sr-rich phase. Variable-temperature 23Na and 17O magic-angle-spinning NMR up to 618 °C have shown significant changes in Na ion dynamics at high temperatures but little oxide ion motion, suggesting that Na ions are responsible for the observed high ionic conductivity. In addition, β-Na 2Si 2O 5 starts to crystallize at temperatures higher than 480 °C with prolonged heating, resulting in reduction in Na+ motion, and thus degradation of ionic conductivity. This study has contributed critical evidence to the understanding of ionic conduction in Na-doped SrSiO 3 and demonstrated that multinuclear high-resolution and high-temperature solid-state NMR is a uniquely useful tool for investigating ion conductors at their operating conditions.« less

On the origin of high ionic conductivity in Na-doped SrSiO 3

DOE PAGES

Chien, Po-Hsiu; Jee, Youngseok; Huang, Chen; ...

2016-02-17

Understanding the local structure and ion dynamics is at the heart of ion conductor research. This paper reports on high-resolution solid-state 29Si, 23Na, and 17O NMR investigation of the structure, chemical composition, and ion dynamics of a newly discovered fast ion conductor, Na-doped SrSiO 3, which exhibited a much higher ionic conductivity than most of current oxide ion conductors. Quantitative analyses reveal that with a small dose (<10 mol%) of Na, the doped Na integrates into the SrSiO 3 structure to form Na xSr 1-xSiO 3-0.5x, and with >10 mol% Na doping, phase separation occurs, leading to the formation ofmore » an amorphous phase β-Na 2Si 2O 5 and a crystalline Sr-rich phase. Variable-temperature 23Na and 17O magic-angle-spinning NMR up to 618 °C have shown significant changes in Na ion dynamics at high temperatures but little oxide ion motion, suggesting that Na ions are responsible for the observed high ionic conductivity. In addition, β-Na 2Si 2O 5 starts to crystallize at temperatures higher than 480 °C with prolonged heating, resulting in reduction in Na+ motion, and thus degradation of ionic conductivity. This study has contributed critical evidence to the understanding of ionic conduction in Na-doped SrSiO 3 and demonstrated that multinuclear high-resolution and high-temperature solid-state NMR is a uniquely useful tool for investigating ion conductors at their operating conditions.« less

Local Structural Investigations, Defect Formation, and Ionic Conductivity of the Lithium Ionic Conductor Li 4 P 2 S 6

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

Dietrich, Christian; Sadowski, Marcel; Sicolo, Sabrina

Glassy, glass–ceramic, and crystalline lithium thiophosphates have attracted interest in their use as solid electrolytes in all-solid-state batteries. Despite similar structural motifs, including PS 4 3–, P 2S 6 4–, and P 2S 7 4– polyhedra, these materials exhibit a wide range of possible compositions, crystal structures, and ionic conductivities. Here, we present a combined approach of Bragg diffraction, pair distribution function analysis, Raman spectroscopy, and 31P magic angle spinning nuclear magnetic resonance spectroscopy to study the underlying crystal structure of Li 4P 2S 6. In this work, we show that the material crystallizes in a planar structural arrangement asmore » a glass ceramic composite, explaining the observed relatively low ionic conductivity, depending on the fraction of glass content. Calculations based on density functional theory provide an understanding of occurring diffusion pathways and ionic conductivity of this Li + ionic conductor.« less

The influence of the local structure on proton transport in a solid oxide proton conductor La 0.8 Ba 1.2 GaO 3.9

DOE PAGES

Cheng, Yongqiang; Balachandran, Janakiraman; Bi, Zhonghe; ...

2017-07-18

The local structure around the mobile ions influences their dynamics. The knowledge about the relationship between these properties is of fundamental importance and may lead the way for development of improved solid state ionic conductors. Here, we use inelastic neutron scattering and ab initio modeling to study a representative proton conductor, La 0.8Ba 1.2GaO 3.9, where different local structures are possible for the same stoichiometry. The intrinsic correlations between the local bonding environment and the dynamical behavior of protons are presented. In particular, we identify how the local Ba/La concentration affects the proton vibrational frequencies, hydrogen bond strength, O–H rotationsmore » and in turn long-range proton mobility. Furthermore, possible mechanism for proton transport, through the inter-tetrahedral bond switching, O–H rotations and tetrahedral reorientation is anticipated.« less

Oxysulfide LiAlSO: A Lithium Superionic Conductor from First Principles.

PubMed

Wang, Xuelong; Xiao, Ruijuan; Li, Hong; Chen, Liquan

2017-05-12

Through first-principles calculations and crystal structure prediction techniques, we identify a new layered oxysulfide LiAlSO in orthorhombic structure as a novel lithium superionic conductor. Two kinds of stacking sequences of layers of AlS_{2}O_{2} are found in different temperature ranges. Phonon and molecular dynamics simulations verify their dynamic stabilities, and wide band gaps up to 5.6 eV are found by electronic structure calculations. The lithium migration energy barrier simulations reveal the collective interstitial-host ion "kick-off" hopping mode with barriers lower than 50 meV as the dominating conduction mechanism for LiAlSO, indicating it to be a promising solid-state electrolyte in lithium secondary batteries with fast ionic conductivity and a wide electrochemical window. This is a first attempt in which the lithium superionic conductors are designed by the crystal structure prediction method and may help explore other mixed-anion battery materials.

Oxysulfide LiAlSO: A Lithium Superionic Conductor from First Principles

NASA Astrophysics Data System (ADS)

Wang, Xuelong; Xiao, Ruijuan; Li, Hong; Chen, Liquan

2017-05-01

Through first-principles calculations and crystal structure prediction techniques, we identify a new layered oxysulfide LiAlSO in orthorhombic structure as a novel lithium superionic conductor. Two kinds of stacking sequences of layers of AlS2O2 are found in different temperature ranges. Phonon and molecular dynamics simulations verify their dynamic stabilities, and wide band gaps up to 5.6 eV are found by electronic structure calculations. The lithium migration energy barrier simulations reveal the collective interstitial-host ion "kick-off" hopping mode with barriers lower than 50 meV as the dominating conduction mechanism for LiAlSO, indicating it to be a promising solid-state electrolyte in lithium secondary batteries with fast ionic conductivity and a wide electrochemical window. This is a first attempt in which the lithium superionic conductors are designed by the crystal structure prediction method and may help explore other mixed-anion battery materials.

Mixed Electronic and Ionic Conductor-Coated Cathode Material for High-Voltage Lithium Ion Battery.

PubMed

Shim, Jae-Hyun; Han, Jung-Min; Lee, Joon-Hyung; Lee, Sanghun

2016-05-18

A lithium ionic conductor, Li1.3Al0.3Ti1.7(PO4)3 (LATP), is introduced as a coating material on the surface of Mg-doped LiCoO2 to improve electrochemical performances for high-voltage (4.5 V) lithium ion batteries. Structure, morphology, elemental distribution, and electrical properties of the materials are thoroughly characterized by SEM, TEM, EELS, EDS, and C-AFM. The coating layer is electrically conductive with the aid of Mg ions which are used as a dopant for the active materials; therefore, this mixed electronic ionic conductor strongly enhances the electrochemical performances of initial capacity, cycling property, and rate capability. The LATP coating layer also demonstrates very promising applicability for 4.4 V prismatic full cells with graphite anode, which correspond to the 4.5 V half-cells with lithium anode. The 2900 mA h full cells show 85% of capacity retention after 500 cycles and more than 60% after 700 cycles.

New chemical approach to obtain dense layer phosphate-based ionic conductor coating on negative electrode material surface: Synthesis way, outgassing and improvement of C-rate capability

NASA Astrophysics Data System (ADS)

Fleutot, Benoit; Davoisne, Carine; Gachot, Grégory; Cavalaglio, Sébastien; Grugeon, Sylvie; Viallet, Virginie

2017-04-01

Li4Ti5O12 (LTO) based batteries have severe gassing behavior during charge/discharge and storage process, due to interfacial reactions between active material and electrolyte solution. In the same time, the electronic and ionic conductivity of pristine LTO is very poor and induces the use of nanoparticles which increase the outgassing phenomena. The coating of LTO particles could be a solution. For this the LTO spinel particles are modified with ionic conductor Li3PO4 coating using a spray-drying method. For the first time a homogeneous thin dense layer phosphate based conductor is obtained without nanoparticles, as a thin film material. It is so possible to study the influence of ionic conductor deposited on the negative electrode material on performances by the controlled layer thickness. This coating was characterized by XRD, SEM, XPS and TEM. The electrochemical performance of Li3PO4 coated Li4Ti5O12 is improved at high C-rate by the surface modification (improvement of 30 mAh g-1 at 5 C-rate compared to pristine LTO for 5 nm of coating), inducing by a modification of surface energy. An optimum coating thickness was studied. This type of coating allows a significant decrease of outgassing phenomena due the conformal coating and opens the way to a great number of studies and new technologies.

Ionic skin.

PubMed

Sun, Jeong-Yun; Keplinger, Christoph; Whitesides, George M; Suo, Zhigang

2014-12-03

Electronic skins (i.e., stretchable sheets of distributed sensors) report signals using electrons, whereas natural skins report signals using ions. Here, ionic conductors are used to create a new type of sensory sheet, called "ionic skin". Ionic skins are highly stretchable, transparent, and biocompatible. They readily measure strains from 1% to 500%, and pressures as low as 1 kPa. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic structures of superionic conductor Li3N

NASA Astrophysics Data System (ADS)

Aoki, Masaru; Ode, Yoshiyuki; Tsumuraya, Kazuo

2011-03-01

Lithium nitride is a superionic conductor with high Li conductivity. The compound has been studied extensively because of its potential utility as electrolyte in solid-state batteries. Though the mobility of the cations within the crystalline solid is high comparable to that of molten salts, the mechanism of the high mobility of the cations remains unsolved. To clarify the origin of the mobility we investigate the electronic states of the Li cations in the Li 3 N crystal with the first principles electronic structure analysis, focusing a correlation between the cations and the ionicities of the constituent atoms. We have found the existence of the covalent bonding between the Li atoms in the Li 3 N crystal in spite of the ionized states of the constituent atoms.

Capacitance of the Double Layer Formed at the Metal/Ionic-Conductor Interface: How Large Can It Be?

NASA Astrophysics Data System (ADS)

Skinner, Brian; Loth, M. S.; Shklovskii, B. I.

2010-03-01

The capacitance of the double layer formed at a metal/ionic-conductor interface can be remarkably large, so that the apparent width of the double layer is as small as 0.3 Å. Mean-field theories fail to explain such large capacitance. We propose an alternate theory of the ionic double layer which allows for the binding of discrete ions to their image charges in the metal. We show that at small voltages the capacitance of the double layer is limited only by the weak dipole-dipole repulsion between bound ions, and is therefore very large. At large voltages the depletion of bound ions from one of the capacitor electrodes triggers a collapse of the capacitance to the mean-field value.

A study of fast ionic conductors by positron annihilation

NASA Astrophysics Data System (ADS)

Wang, Yung-Yu; Yang, Ju-Hua; Pan, Xiao-Liang; Lei, Zhen-Xi

1988-06-01

New fast ionic conductor systems of LiCl-LiF-B2O3 and LiF-B2O3 were studied by using the positron annihilation technique. It was found that the mid-life intensity I2 in positron annihilation has a linear relationship with the material's electrical conductivity log sigma. This result, combined with the measurement result on the linear annihilation parameter, indicated that the voids between microcrystals and network phases provided more transfer paths in the micro-crystalline LiF-LiCl-B2O3 system, which led to improved electrical conductivity in this type of material.

Composite oxygen ion transport element

DOEpatents

Chen, Jack C [Getzville, NY; Besecker, Charles J [Batavia, IL; Chen, Hancun [Williamsville, NY; Robinson, Earil T [Mentor, OH

2007-06-12

A composite oxygen ion transport element that has a layered structure formed by a dense layer to transport oxygen ions and electrons and a porous support layer to provide mechanical support. The dense layer can be formed of a mixture of a mixed conductor, an ionic conductor, and a metal. The porous support layer can be fabricated from an oxide dispersion strengthened metal, a metal-reinforced intermetallic alloy, a boron-doped Mo.sub.5Si.sub.3-based intermetallic alloy or combinations thereof. The support layer can be provided with a network of non-interconnected pores and each of said pores communicates between opposite surfaces of said support layer. Such a support layer can be advantageously employed to reduce diffusion resistance in any type of element, including those using a different material makeup than that outlined above.

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

Cheng, Yongqiang; Balachandran, Janakiraman; Bi, Zhonghe

The local structure around the mobile ions influences their dynamics. The knowledge about the relationship between these properties is of fundamental importance and may lead the way for development of improved solid state ionic conductors. Here, we use inelastic neutron scattering and ab initio modeling to study a representative proton conductor, La 0.8Ba 1.2GaO 3.9, where different local structures are possible for the same stoichiometry. The intrinsic correlations between the local bonding environment and the dynamical behavior of protons are presented. In particular, we identify how the local Ba/La concentration affects the proton vibrational frequencies, hydrogen bond strength, O–H rotationsmore » and in turn long-range proton mobility. Furthermore, possible mechanism for proton transport, through the inter-tetrahedral bond switching, O–H rotations and tetrahedral reorientation is anticipated.« less

Highly Efficient Plastic Crystal Ionic Conductors for Solid-state Dye-sensitized Solar Cells

PubMed Central

Hwang, Daesub; Kim, Dong Young; Jo, Seong Mu; Armel, Vanessa; MacFarlane, Douglas R.; Kim, Dongho; Jang, Sung-Yeon

2013-01-01

We have developed highly efficient, ambient temperature, solid-state ionic conductors (SSICs) for dye-sensitized solar cells (DSSCs) by doping a molecular plastic crystal, succinonitrile (SN), with trialkyl-substituted imidazolium iodide salts. High performance SSICs with enhanced ionic conductivity (2–4 mScm−1) were obtained. High performance solid-state DSSCs with power conversion efficiency of 7.8% were fabricated using our SSICs combined with unique hierarchically nanostructured TiO2 sphere (TiO2-SP) photoelectrodes; these electrodes have significant macroporosity, which assists penetration of the solid electrolyte into the electrode. The performance of our solid-state DSSCs is, to the best of our knowledge, the highest reported thus far for cells using plastic crystal-based SSICs, and is comparable to that of the state-of-the-art DSSCs which use ionic liquid type electrolytes. This report provides a logical strategy for the development of efficient plastic crystal-based SSICs for DSSCs and other electrochemical devices. PMID:24343425

Lithium-Based High Energy Density Flow Batteries

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor); Kindler, Andrew (Inventor); Smart, Marshall C. (Inventor)

2014-01-01

Systems and methods in accordance with embodiments of the invention implement a lithium-based high energy density flow battery. In one embodiment, a lithium-based high energy density flow battery includes a first anodic conductive solution that includes a lithium polyaromatic hydrocarbon complex dissolved in a solvent, a second cathodic conductive solution that includes a cathodic complex dissolved in a solvent, a solid lithium ion conductor disposed so as to separate the first solution from the second solution, such that the first conductive solution, the second conductive solution, and the solid lithium ionic conductor define a circuit, where when the circuit is closed, lithium from the lithium polyaromatic hydrocarbon complex in the first conductive solution dissociates from the lithium polyaromatic hydrocarbon complex, migrates through the solid lithium ionic conductor, and associates with the cathodic complex of the second conductive solution, and a current is generated.

A dendrite-suppressing composite ion conductor from aramid nanofibres.

PubMed

Tung, Siu-On; Ho, Szushen; Yang, Ming; Zhang, Ruilin; Kotov, Nicholas A

2015-01-27

Dendrite growth threatens the safety of batteries by piercing the ion-transporting separators between the cathode and anode. Finding a dendrite-suppressing material that combines high modulus and high ionic conductance has long been considered a major technological and materials science challenge. Here we demonstrate that these properties can be attained in a composite made from Kevlar-derived aramid nanofibres assembled in a layer-by-layer manner with poly(ethylene oxide). Importantly, the porosity of the membranes is smaller than the growth area of the dendrites so that aramid nanofibres eliminate 'weak links' where the dendrites pierce the membranes. The aramid nanofibre network suppresses poly(ethylene oxide) crystallization detrimental for ion transport, giving a composite that exhibits high modulus, ionic conductivity, flexibility, ion flux rates and thermal stability. Successful suppression of hard copper dendrites by the composite ion conductor at extreme discharge conditions is demonstrated, thereby providing a new approach for the materials engineering of solid ion conductors.

Revealing the Charge Transport Mechanism in Polymerized Ionic Liquids: Insight from High Pressure Conductivity Studies

DOE PAGES

Wojnarowska, Zaneta; Feng, Hongbo; Diaz, Mariana; ...

2017-09-05

Polymerized ionic liquids (polyILs), composed mostly of organic ions covalently bonded to the polymer backbone and free counterions, are considered as an ideal electrolytes for various electrochemical devices, including fuel cells, supercapacitors and batteries. Despite large structural diversity of these systems, all of them reveal a universal but poorly understood feature - a charge transport faster than the segmental dynamics. Here, to address this issue, we have studied three novel polymer electrolyte membrane for fuel cells as well as four single-ion conductors including highly conductive siloxane-based polyIL. Our ambient and high pressure studies revealed fundamental differences in the conducting propertiesmore » of the examined systems. Finally, we demonstrate that the proposed methodology is a powerful tool to identify the charge transport mechanism in polyILs in general and thereby contribute to unraveling the microscopic nature of the decoupling phenomenon in these materials.« less

Revealing the Charge Transport Mechanism in Polymerized Ionic Liquids: Insight from High Pressure Conductivity Studies

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

Wojnarowska, Zaneta; Feng, Hongbo; Diaz, Mariana

Polymerized ionic liquids (polyILs), composed mostly of organic ions covalently bonded to the polymer backbone and free counterions, are considered as an ideal electrolytes for various electrochemical devices, including fuel cells, supercapacitors and batteries. Despite large structural diversity of these systems, all of them reveal a universal but poorly understood feature - a charge transport faster than the segmental dynamics. Here, to address this issue, we have studied three novel polymer electrolyte membrane for fuel cells as well as four single-ion conductors including highly conductive siloxane-based polyIL. Our ambient and high pressure studies revealed fundamental differences in the conducting propertiesmore » of the examined systems. Finally, we demonstrate that the proposed methodology is a powerful tool to identify the charge transport mechanism in polyILs in general and thereby contribute to unraveling the microscopic nature of the decoupling phenomenon in these materials.« less

Extensional ionomeric polymer conductor composite actuators with ionic liquids

NASA Astrophysics Data System (ADS)

Liu, Sheng; Lin, Minren; Zhang, Qiming

2008-03-01

Although the Ionic Polymer-Metal Composite (IPMC) actuators developed up to date are in the form of bending actuators, development of extensional actuators based on IMPC is highly desirable from practical applications and fundamental understanding points of view. This talk presents the design, fabrication and characterization of a recent work on an extensional Ionic Polymer-Metal Composite actuator. The extensional actuator consists of the Nafion ionomer as the matrix and the sub-micron size RuO II particles as the conductive filler for the conductor/ionomr composites. In this investigation, several ionic liquids (IL) were investigated. For a Nafion/RuO II composite with 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf) IL, it was found that as the ions are driven into the ionomer/RuO II composite (the composite under negative voltage), an extensional strain of 0.9% was observed; while as the ions were expelled from the ionomer/RuO II composite (under positive voltage), a contraction of -1.2% was observed. The results indicate that multiple ions are participating in charge transport and actuation process. In this paper, we also discuss several design considerations for future extensional actuators with fast response, much improved strain and stress level. Especially an actuator based on multilayer configuration can significantly increase the electric field level in the actuator and consequently significantly improve the actuator speed. The extensional actuator investigated here provides a unique platform to investigate various phenomena related to ion transport and their interaction with the ionomer/conductor matrix to realize high electromechanical performance.

Polarization effect in the Ionic conductor TlBr

NASA Astrophysics Data System (ADS)

Rocha Leao, Cedric; Lordi, Vincenzo

2012-02-01

TlBr is an ionic crystal that in recent years has been standing out as one of the most promising materials for effective room temperature radiation detection. However, its exceptional performance invariably degrades after operation times that vary from hours to several weeks. This phenomenon, known as polarization, is assigned to the undesirable ionic current that sets in the crystal under an applied bias, leading to the accumulation of oppositely charged Tl+ and Br- ions at the electric contacts of the device. This charge build up induces a field that opposes the applied bias, impairing the collection of the photo-induced carriers. In this presentation, we use parameter free quantum mechanical simulations to discuss the possible origins of the polarization effect in TlBr, showing that ionic mobility in the intrinsic material is not enough to account for effects reported by several groups. We then discuss other possible causes for the degradation of biased TlBr and propose ways to prevent its occurrence, via careful co-doping as well as a judicious choice of the metal contacts to be employed.

Microphase separation and the formation of ion conductivity channels in poly(ionic liquid)s: A coarse-grained molecular dynamics study

NASA Astrophysics Data System (ADS)

Weyman, Alexander; Bier, Markus; Holm, Christian; Smiatek, Jens

2018-05-01

We study generic properties of poly(ionic liquid)s (PILs) via coarse-grained molecular dynamics simulations in bulk solution and under confinement. The influence of different side chain lengths on the spatial properties of the PIL systems and on the ionic transport mechanism is investigated in detail. Our results reveal the formation of apolar and polar nanodomains with increasing side chain length in good agreement with previous results for molecular ionic liquids. The ion transport numbers are unaffected by the occurrence of these domains, and the corresponding values highlight the potential role of PILs as single-ion conductors in electrochemical devices. In contrast to bulk behavior, a pronounced formation of ion conductivity channels in confined systems is initiated in close vicinity to the boundaries. We observe higher ion conductivities in these channels for increasing PIL side chain lengths in comparison with bulk values and provide an explanation for this effect. The appearance of these domains points to an improved application of PILs in modern polymer electrolyte batteries.

First-principles investigations of ionic conduction in Li and Na borohydrides

NASA Astrophysics Data System (ADS)

Varley, Joel; Heo, Tae-Wook; Ray, Keith; Bonev, Stanimir; Wood, Brandon

Recent experimental studies have identified a family of alkali borohydride materials that exhibit superionic transition temperatures approaching room temperature and ionic conductivities exceeding 0.1 S/cm-1, making them highly promising solid electrolytes for next-generation batteries. Despite the rapid advances in improving the superionic conductivity in these materials, an understanding of the exact mechanisms driving the transport remains unknown. Here we use ab initio molecular dynamics calculations to address this issue by characterizing the diffusivity of the Li and Na species in a representative set of closoborane ionic conductors. We investigate both the Na and Li-containing borohydrides with icosahedral (B12H12) and double-capped square antiprism (B10H10) anion species and discuss the trends in ionic conductivity as a function of stoichiometry and the incorporation of various dopants. Our results support the borohydrides as a subset of a larger family of very promising solid electrolytes and identify strategies to improving the conductivity in these materials. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Development and Implementation of Carbon Nanofoam Cathode Structures for Magnesium-Hydrogen Peroxide Semi-Fuel Cells

DTIC Science & Technology

2008-05-05

ionic solution) or a solid ionic conductor (e.g. Nafion ). An external circuit electronically connects the anode and cathode to each other. The...polymers. Aerogels could be the first nanoarchitectures, dating back to the 1930’s when Steven Kistler recognized a technique to remove liquid from a

Lithium Fast-Ion Conductors: Polymer Based Materials.

DTIC Science & Technology

1987-05-30

significant ambient temperature ionic conductivities. Some of the -aterials may be of interest in other contexts. A study of lithium tetra...This work was a search for lithium-containing materials with ambient temperature ionic conductivities of 10- 5 (ohm-cm) " or larger. The work began with...1-8). The discovery of solids, e.g., sodium.8-alumina(l), and polymer-salt complexes, e.g., (PEO) 8 LiCIO 4 (3), with ionic conductivities approaching

A dendrite-suppressing composite ion conductor from aramid nanofibres

NASA Astrophysics Data System (ADS)

Tung, Siu-On; Ho, Szushen; Yang, Ming; Zhang, Ruilin; Kotov, Nicholas A.

2015-01-01

Dendrite growth threatens the safety of batteries by piercing the ion-transporting separators between the cathode and anode. Finding a dendrite-suppressing material that combines high modulus and high ionic conductance has long been considered a major technological and materials science challenge. Here we demonstrate that these properties can be attained in a composite made from Kevlar-derived aramid nanofibres assembled in a layer-by-layer manner with poly(ethylene oxide). Importantly, the porosity of the membranes is smaller than the growth area of the dendrites so that aramid nanofibres eliminate ‘weak links’ where the dendrites pierce the membranes. The aramid nanofibre network suppresses poly(ethylene oxide) crystallization detrimental for ion transport, giving a composite that exhibits high modulus, ionic conductivity, flexibility, ion flux rates and thermal stability. Successful suppression of hard copper dendrites by the composite ion conductor at extreme discharge conditions is demonstrated, thereby providing a new approach for the materials engineering of solid ion conductors.

Ion transferring in polyelectrolyte networks in electric fields

NASA Astrophysics Data System (ADS)

Li, Honghao; Erbas, Aykut; Zwanikken, Jos; Olvera de La Cruz, Monica

Ion-conducting polyelectrolyte gels have drawn the attention of many researchers in the last few decades as they have wide applications not only in lithium batteries but also as stretchable, transparent ionic conductor or ionic cables devices. However, ion dynamics in polyelectrolyte gels has been much less studied analytically or computationally due to the complicated interplay of long-range electrostatic and short-range interactions. Here we propose a coarse-grained non-equilibrium molecular dynamics simulation to study the ion dynamics in polyelectrolyte gels under external electric fields. We found a nonlinear response region where the molar conductivity of polyelectrolyte gels increases with external fields. We propose counterion redistribution under electric fields as the driving mechanism. We also found the ionic conductivity to be modulated by changing polylelectrolyte network topology such as the chain length. Our discovery reveals the essential difference of ion dynamics between electrolytes and polyelectrolyte gels. These results will expand our understanding in charged polymeric systems and help in designing ion-conducting devices with higher conductivity.

Recent Advances in Fast Ion Conducting Materials and Devices - Proceedings of the 2nd Asian Conference on Solid State Ionics

NASA Astrophysics Data System (ADS)

Chowdari, B. V. R.; Liu, Qingguo; Chen, Liquan

The Table of Contents for the book is as follows: * Preface * Invited Papers * Recent Trends in Solid State Ionics * Theoretical Aspects of Fast Ion Conduction in Solids * Chemical Bonding and Intercalation Processes in Framework Structures * Extra-Large Near-Electrode Regions and Diffusion Length on the Solid Electrolyte-Electrode Interface as Studied by Photo-EMF Method * Frequency Response of Glasses * XPS Studies on Ion Conducting Glasses * Characterization of New Ambient Temperature Lithium Polymer-Electrolyte * Recent Development of Polymer Electrolytes: Solid State Voltammetry in Polymer Electrolytes * Secondary Solid State Batteries: From Material Properties to Commercial Development * Silver Vanadium Oxide Bronze and its Applications for Electrochemical Devices * Study on β''-Alumina Solid Electrolyte and β Battery in SIC * Materials for Solid Oxide Fuel Cells * Processing for Super Superionic Ceramics * Hydrogen Production Using Oxide Ionic or Protonic Conductor * Ionically Conductive Sulfide-Based Lithium Glasses * Relation of Conductivity to Structure and Structural Relaxation in Ion-Conducting Glasses * The Mechanism of Ionic Conductivity in Glass * The Role of Synthesis and Structure in Solid State Ionics - Electrodes to Superconductors * Electrochromism in Spin-Coated Thin Films from Peroxo-Poly tungstate Solutions * Electrochemical Studies on High Tc Superconductors * Multivalence Fast Ionic Conductors - Montmorillonites * Contributed Papers * Volt-Ampere Characteristics and Interface Charge Transport in Solid Electrolytes * Internal Friction of Silver Chalcogenides * Thermal Expansion of Ionic and Superionic Solids * Improvement of PEO-LiCF3SO3 Complex Electrolytes Using Additives * Ionic Conductivity of Modified Poly (Methoxy Polyethylene Glycol Methacrylate) s-Lithium Salt Complexes * Solid Polymer Electrolytes of Crosslinked Polyethylene Glycol and Lithium Salts * Single Ionic Conductors Prepared by in Situ Polymerization of Methacrylic Acid Alkali Metal Salts in Polyethylene Oxide * Redox Behavior of Alkyl Viologens in Ion Conductive Polymer Solid * Ionic Conductivity of Interpenetrating Polymer Networks Containing LiClO4 * Electrochemical Behaviors of Porphyrins Incorporated into Solid Polymer Electrolytes * Lithium Ion Conducting Polymer Electrolytes * Electrochemical Synthesis of Polyaniline Thin Film * Electrochemical Aspect of Polyaniline Electrode in Aqueous Electrolyte * Mixed Cation Effect in Epoxy Resin - PEO-IPN Containing Perchlorate Salts * Conductivity, Raman and IR Studies on the Doped PEO-PPG Polymer Blends * Proton Conducting Polymeric Electrolytes from Poly (Ethyleneoxide) System * Surface Structure of Polymer Solid Ionic Conductors Based on Segmented Polyether Polyurethaneureas * Study on Addition Products of LiI and Diethylene Glycol etc. * Solid State Rechargeable Battery Using Paper Form Copper Ion Conductive Solid Electrolyte * Characterization of Electrode/Electrolyte Interfaces in Battery Li/PVAC-Li-Mont./Li1+xV3O8 by AC Impedance Method * Investigation on Reversibility of Vanadium Oxide Cathode Materials in Solid-State Battery * Preparation and Characterization of Silver Boromolybdate Solid State Batteries * The Electric Properties of the Trinary Cathode Material and its Application in Magnisium Solid State Cell * Electrical Properties and Phase Relation of Na2Mo0.1S0.9O4 Doped with Rare Earth Sulfate * New Electrochemical Probe for Rapid Determination of Silicon Concentration in Hot Metals * A New Theoretical EMF Expression for SOx(x = 2, 3) Sensors Based on Na2SO4 Solid Electrolyte * Evaluation of the Electrochemical SOx(x = 2, 3) Sensor with a Tubular Nasicon Electrolyte * The Response Time of a Modified Oxygen Sensor Using Zirconia Electrolyte * Preparation, Characteristics and Sintering Behavior of MgO-PSZ Powder * Reaction between La0.9MnO3 and Yttria Doped Zirconia * Development of the Extended-Life Oxygen Sensor of Caβ''-Al2O3 * Caβ''-Al2O3 Ultra-Low Oxygen Sensor * Measurement of Sulfur Concentration with Zirconia-Based Electrolyte Cell in Molten Iron * Influence of SO2 on the Conductivity of Calcia Stabilized Zirconia * Reactions between YSZ and La1-xCaxMnO3 as a Cathode for SOFC * Preparation and Electrical Properties of Lithium β''-Alumina * Influence of Lithia Content on Properties of β''-Alumina Ceramics * Electrical Conductivity of Solid Solutions of Na2SO4 with Na2SeO4 * Effect of Antagonist XO42- = MoO42- and WO42- Ion Substitution on the Electrical Conductivity of Li2SO4 : Li2CO3 Eutectic System * Study on the Electrical Properties and Structure of Multicrystal Materials Li5+xGe1-xCrxV3O12 * Preliminary Study on Synthesis of Silver Zirconium Silicophosphates by Sol - Gel Process * Sodium Ion Conduction in Iron(III) Exchanged Y Zeolite * Electrical Properties of V5O9+x (x = 0, 1) and CuxV5O9.1 * Electrical Properties of the Tetragonal ZrO2 Stabilized with CeO2, CeO2 + Gd2O3 * Study of Preparation and Ionic Conduction of Doped Barium Cerate Perovskite * Preparing Fine Alumina Powder by Homogeneous Precipitation Method for Fabricating β''-Al2O3 * Amorphous Lithium Ion Conductors in Li2S-SiS2-LiBO2 System * Mixed Alkali Effect of Glass Super Ionic Conductors * Electrical Property and Phase Separation, Crystallization Behavior of A Cu+-Conducting Glass * Investigation of Phase Separation and Crystallization for 0.4CuI-0.3 Cu2O-0.3P2O5 Glass by SEM and XRD * Study on the Lithium Solid Electrolytes of Li3N-LiX(X = F, Cl, Br, I)-B2O3 Ternary Systems * Synthesis and Characterization of the Li2O : P2O5 : WO3 Glasses * The Electrochromic Properties of Electrodeposited Ni-O Films in Nonaqueous Electrolytes * All Solid-State WO3-MnO2 Based Electrochromic Window * Electrochromism in Nickel Oxide Films * E S R of X-Irradiated Melt Quenched Li2SO4 * Mixed-Alkali Effect in the Li2O-Na2O-TeO2 Glass System * Electrical and Thermal Studies on Silver Tellurite Glasses * Late Entries (Invited Papers) * Proton Conducting Polymers * Light Scattering Studies on Superionic Conductor YSZ * Development of Thin Film Surface Modified Solid State Electrochemical Gas Sensors * Author Index * List of Participants

Direct Observation of Virtual Electrode Formation Through a Novel Electrolyte-to-Electrode Transition

NASA Astrophysics Data System (ADS)

Siegel, David; El Gabaly, Farid; Bartelt, Norman; McCarty, Kevin

2014-03-01

Novel electrochemical solutions to problems in energy storage and transportation can drive renewable energy to become an economically viable alternative to fossil fuels. In many electrochemical systems, the behavior of a device can be fundamentally limited by the surface area of a triple phase boundary, the boundary region where a gas-phase species, electrode, and electrolyte coincide. When the electrode is an ionic insulator the triple phase boundary is typically a one-dimensional boundary with nanometer-scale thickness: ions cannot transport through the electrode, while electrons cannot be transported through the electrolyte. Here we present direct experimental measurements of a novel electrolyte-to-electrode transition with photoemission electron microscopy, and observe that the surface of an ionically conductive, electronically insulative solid oxide electrolyte undergoes a transition into a mixed electron-ion conductor in the vicinity of a metal electrode. Our direct experimental measurements allow us to characterize this system and address the mechanisms of ionic reactions and transport through comparisons with theoretical modeling to provide us with a physical picture of the processes involved. Our results provide insight into one of the mechanisms of ion transport in an electrochemical cell that may be generalizable to other systems.

Direct measurement of the electric-field distribution in a light-emitting electrochemical cell

NASA Astrophysics Data System (ADS)

Slinker, Jason D.; Defranco, John A.; Jaquith, Michael J.; Silveira, William R.; Zhong, Yu-Wu; Moran-Mirabal, Jose M.; Craighead, Harold G.; Abruña, Héctor D.; Marohn, John A.; Malliaras, George G.

2007-11-01

The interplay between ionic and electronic charge carriers in mixed conductors offers rich physics and unique device potential. In light-emitting electrochemical cells (LEECs), for example, the redistribution of ions assists the injection of electronic carriers and leads to efficient light emission. The mechanism of operation of LEECs has been controversial, as there is no consensus regarding the distribution of electric field in these devices. Here, we probe the operation of LEECs using electric force microscopy on planar devices. We show that obtaining the appropriate boundary conditions is essential for capturing the underlying device physics. A patterning scheme that avoids overlap between the mixed-conductor layer and the metal electrodes enabled the accurate in situ measurement of the electric-field distribution. The results show that accumulation and depletion of mobile ions near the electrodes create high interfacial electric fields that enhance the injection of electronic carriers.

Nonhumidified intermediate temperature fuel cells using protic ionic liquids.

PubMed

Lee, Seung-Yul; Ogawa, Atsushi; Kanno, Michihiro; Nakamoto, Hirofumi; Yasuda, Tomohiro; Watanabe, Masayoshi

2010-07-21

In this paper, the characterization of a protic ionic liquid, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), as a proton conductor for a fuel cell and the fabrication of a membrane-type fuel cell system using [dema][TfO] under nonhumidified conditions at intermediate temperatures are described in detail. In terms of physicochemical and electrochemical properties, [dema][TfO] exhibits high activity for fuel cell electrode reactions (i.e., the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR)) at a Pt electrode, and the open circuit voltage (OCV) of a liquid fuel cell is 1.03 V at 150 degrees C, as has reported in ref 27. However, diethylmethylammonium bis(trifluoromethane sulfonyl)amide ([dema][NTf(2)]) has relatively low HOR and ORR activity, and thus, the OCV is ca. 0.7 V, although [dema][NTf(2)] and [dema][TfO] have an identical cation ([dema]) and similar thermal and bulk-transport properties. Proton conduction occurs mainly via the vehicle mechanism in [dema][TfO] and the proton transference number (t(+)) is 0.5-0.6. This relatively low t(+) appears to be more disadvantageous for a proton conductor than for other electrolytes such as hydrated sulfonated polymer electrolyte membranes (t(+) = 1.0). However, fast proton-exchange reactions occur between ammonium cations and amines in a model compound. This indicates that the proton-exchange mechanism contributes to the fuel cell system under operation, where deprotonated amines are continuously generated by the cathodic reaction, and that polarization of the cell is avoided. Six-membered sulfonated polyimides in the diethylmethylammonium form exhibit excellent compatibility with [dema][TfO]. The composite membranes can be obtained up to a [dema][TfO] content of 80 wt % and exhibit good thermal stability, high ionic conductivity, and mechanical strength and gas permeation comparable to those of hydrated Nafion. H(2)/O(2) fuel cells prepared using the composite membranes can successfully operate at temperatures from 30 to 140 degrees C under nonhumidified conditions, and a current density of 250 mA cm(-2) is achieved at 120 degrees C. The protic ionic liquid and its composite membrane are a possible candidate for an electrolyte of a H(2)/O(2) fuel cell that operates under nonhumidified conditions.

Extended x-ray absorption fine structure spectroscopy and x-ray absorption near edge spectroscopy study of aliovalent doped ceria to correlate local structural changes with oxygen vacancies clustering

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

Shirbhate, S. C.; Acharya, S. A., E-mail: saha275@yahoo.com; Yadav, A. K.

2016-04-04

This study provides atomic scale insight to understand the role of aliovalent dopants on oxygen vacancies clustering and dissociation mechanism in ceria system in order to enhance the performance of oxy-ion conductor. Dopants induced microscale changes in ceria are probed by extended X-ray absorption fine structure spectroscopy, X-ray absorption near edge spectra, and Raman spectroscopy. The results are explored to establish a correlation between atomic level structural changes (coordination number, interatomic spacing) → formation of dimer and trimer type cation-oxygen vacancies defect complex (intrinsic and extrinsic) → dissociation of oxygen vacancies from defect cluster → ionic conductivity temperature. It ismore » a strategic approach to understand key physics of ionic conductivity mechanism in order to reduce operating temperature of electrolytes for intermediate temperature (300–450 °C) electrochemical devices for the first time.« less

Enhanced Electrochemical Performance of Fast Ionic Conductor LiTi2(PO4)3-Coated LiNi1/3Co1/3Mn1/3O2 Cathode Material.

PubMed

Zhang, Lu-Lu; Wang, Ji-Qing; Yang, Xue-Lin; Liang, Gan; Li, Tao; Yu, Peng-Lin; Ma, Di

2018-04-11

Layered LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333) is successfully coated by fast ionic conductor LiTi 2 (PO 4 ) 3 (LTP) via a wet chemical method. The effects of LTP on the physicochemical properties and electrochemical performance are studied. The results reveal that a highly layered structure of NCM333 can be well maintained with less cation mixing after LTP coating. LTP of about 5 nm thickness is coated on the surface of NCM333. Such an LTP coating layer can effectively suppress the side reactions between NCM333 and electrolyte but will not hinder the lithium ion transmission. As a result, LTP-coated NCM333 owns an improved capability and cyclic performance, for example, NCM333/LTP delivers an initial capacity as high as 121.0 mA h g -1 with a capacity retention ratio of 82.3% after 200 cycles at 10 C, whereas NCM333 only has an initial capacity of 120.4 mA h g -1 with a very low capacity retention ratio of 66.4%. This method of using a fast ionic conductor like LTP as a coating material may provide a simple and effective strategy to modify those electrode materials with poor cyclic performance.

Developmental status and system studies of the monolithic solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Myles, K. M.

The monolithic solid oxide fuel cell (MSOFC) was invented at the Argonne National Laboratory in 1983 and is currently being developed by a team consisting of Argonne National Laboratory and Allied-Signal Aerospace/AiResearch. The MSOFC is an oxide ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. The electrolyte, which conducts oxygens ions from the air side to the fuel side, is yttria-stabilized zirconia (YSZ). All the other materials, that is, the nickel-YSZ anode, the strontium-doped lanthanum manganite cathode, and the doped lanthanum chromite interconnect (bipolar plate), are electronic conductors. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/l at fuel efficiencies over 50 percent, because of small cell size and low resistive losses in the materials. These performances have been approached in laboratory test fuel cell stacks of nominal 125-W capacities.

Antiperovskite Li 3 OCl superionic conductor films for solid-state Li-ion batteries

DOE PAGES

Lü, Xujie; Howard, John W.; Chen, Aiping; ...

2016-02-02

We prepared antiperovskite Li 3OCl superionic conductor films via pulsed laser deposition using a composite target. A significantly enhanced ionic conductivity of 2.0 × 10 -4 S cm -1 at room temperature is achieved, and this value is more than two orders of magnitude higher than that of its bulk counterpart. Moreover, the applicability of Li 3OCl as a solid electrolyte for Li-ion batteries is demonstrated.

Structure and transport properties of a plastic crystal ion conductor: diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate.

PubMed

Jin, Liyu; Nairn, Kate M; Forsyth, Craig M; Seeber, Aaron J; MacFarlane, Douglas R; Howlett, Patrick C; Forsyth, Maria; Pringle, Jennifer M

2012-06-13

Understanding the ion transport behavior of organic ionic plastic crystals (OIPCs) is crucial for their potential application as solid electrolytes in various electrochemical devices such as lithium batteries. In the present work, the ion transport mechanism is elucidated by analyzing experimental data (single-crystal XRD, multinuclear solid-state NMR, DSC, ionic conductivity, and SEM) as well as the theoretical simulations (second moment-based solid static NMR line width simulations) for the OIPC diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate ([P(1,2,2,4)][PF(6)]). This material displays rich phase behavior and advantageous ionic conductivities, with three solid-solid phase transitions and a highly "plastic" and conductive final solid phase in which the conductivity reaches 10(-3) S cm(-1). The crystal structure shows unique channel-like packing of the cations, which may allow the anions to diffuse more easily than the cations at lower temperatures. The strongly phase-dependent static NMR line widths of the (1)H, (19)F, and (31)P nuclei in this material have been well simulated by different levels of molecular motions in different phases. Thus, drawing together of the analytical and computational techniques has allowed the construction of a transport mechanism for [P(1,2,2,4)][PF(6)]. It is also anticipated that utilization of these techniques will allow a more detailed understanding of the transport mechanisms of other plastic crystal electrolyte materials.

Lithium ion conducting ionic electrolytes

DOEpatents

Angell, C.A.; Xu, K.; Liu, C.

1996-01-16

A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100 C or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors. 4 figs.

Lithium ion conducting ionic electrolytes

DOEpatents

Angell, C. Austen; Xu, Kang; Liu, Changle

1996-01-01

A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors.

Superionic Conductivity of Sm3+, Pr3+, and Nd3+ Triple-Doped Ceria through Bulk and Surface Two-Step Doping Approach.

PubMed

Liu, Yanyan; Fan, Liangdong; Cai, Yixiao; Zhang, Wei; Wang, Baoyuan; Zhu, Bin

2017-07-19

Sufficiently high oxygen ion conductivity of electrolyte is critical for good performance of low-temperature solid oxide fuel cells (LT-SOFCs). Notably, material conductivity, reliability, and manufacturing cost are the major barriers hindering LT-SOFC commercialization. Generally, surface properties control the physical and chemical functionalities of materials. Hereby, we report a Sm 3+ , Pr 3+ , and Nd 3+ triple-doped ceria, exhibiting the highest ionic conductivity among reported doped-ceria oxides, 0.125 S cm -1 at 600 °C. It was designed using a two-step wet-chemical coprecipitation method to realize a desired doping for Sm 3+ at the bulk and Pr 3+ /Nd 3+ at surface domains (abbreviated as PNSDC). The redox couple Pr 3+ /Pr 4+ contributes to the extraordinary ionic conductivity. Moreover, the mechanism for ionic conductivity enhancement is demonstrated. The above findings reveal that a joint bulk and surface doping methodology for ceria is a feasible approach to develop new oxide-ion conductors with high impacts on advanced LT-SOFCs.

Artificial solid electrolyte interphase to address the electrochemical degradation of silicon electrodes.

PubMed

Li, Juchuan; Dudney, Nancy J; Nanda, Jagjit; Liang, Chengdu

2014-07-09

Electrochemical degradation on silicon (Si) anodes prevents them from being successfully used in lithium (Li)-ion battery full cells. Unlike the case of graphite anodes, the natural solid electrolyte interphase (SEI) films generated from carbonate electrolytes do not self-passivate on Si, causing continuous electrolyte decomposition and loss of Li ions. In this work, we aim at solving the issue of electrochemical degradation by fabricating artificial SEI films using a solid electrolyte material, lithium phosphorus oxynitride (Lipon), which conducts Li ions and blocks electrons. For Si anodes coated with Lipon of 50 nm or thicker, a significant effect is observed in suppressing electrolyte decomposition, while Lipon of thinner than 40 nm has a limited effect. Ionic and electronic conductivity measurements reveal that the artificial SEI is effective when it is a pure ionic conductor, but electrolyte decomposition is only partially suppressed when the artificial SEI is a mixed electronic-ionic conductor. The critical thickness for this transition in conducting behavior is found to be 40-50 nm. This work provides guidance for designing artificial SEI films for high-capacity Li-ion battery electrodes using solid electrolyte materials.

An air-stable Na 3SbS 4 superionic conductor prepared by a rapid and economic synthetic procedure

DOE PAGES

Wang, Hui; Chen, Yan; Hood, Zachary D.; ...

2016-01-01

All-solid-state sodium batteries, using abundant sodium resources and solid electrolyte, hold much promise for safe, low cost, large-scale energy storage. To realize the practical applications of all solid Na-ion batteries at ambient temperature, the solid electrolytes are required to have high ionic conductivity, chemical stability, and ideally, easy preparation. Ceramic electrolytes show higher ionic conductivity than polymers, but they often require extremely stringent synthesis conditions, either high sintering temperature above 1000 C or long-time, low-energy ball milling. Herein, we report a new synthesis route for Na 3SbS 4, a novel Na superionic conductor that needs much lower processing temperature belowmore » 200 C and easy operation. This new solid electrolyte exhibits a remarkable ionic conductivity of 1.05 mS cm -1 at 25 °C and is chemically stable under ambient atmosphere. In conclusion, this synthesis process provides unique insight into the current state-of-the-art solid electrolyte preparation and opens new possibilities for the design of similar materials.« less

Artificial Solid Electrolyte Interphase to Address the Electrochemical Degradation of Silicon Electrodes

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

Dudney, Nancy J; Nanda, Jagjit; Liang, Chengdu

2014-01-01

Electrochemical degradation on Si anodes prevents them from being successfully used in lithium-ion full cells. Unlike the case of graphite anodes, natural solid electrolyte interphase (SEI) films generated from carbonate electrolyte do not self-passivate on Si and causes continuous electrolyte decomposition. In this work we aim at solving the issue of electrochemical degradation by fabricating artificial SEI films using a solid electrolyte material, lithium phosphor oxynitride (Lipon), that conducts Li ions and blocks electrons. For Si anodes coated with Lipon of 50 nm or thicker, significant effect is observed in suppressing the electrolyte decomposition, while Lipon of thinner than 40more » nm has little effect. Ionic and electronic conductivity measurement reveals that the artificial SEI is effective when it is a pure ionic conductor, and the electrolyte decomposition is not suppressed when the artificial SEI is a mixed electronic-ionic conductor. The critical thickness for this transition in conducting behavior is found to be 40~50 nm. This work provides guidance for designing artificial SEI for high capacity lithium-ion battery electrodes using solid electrolyte materials.« less

Electrical screening procedure for solid ionic conductors

NASA Technical Reports Server (NTRS)

Kautz, H. E.; Singer, J.; Fielder, W. L.; Fordyce, J. S.

1973-01-01

An electrical screening method has been developed for preliminary evaluation of polycrystalline specimens of candidates for use as solid ionic conductive electrolytes in batteries. The procedure measures dielectric loss and capacitance, from which are calculated an ac conductivity attributed provisionally to ions and an activation energy for that conductivity. Electronic conductivity is directly measured. The screening procedure applied to sodium beta-alumina yielded acceptable values for conductivity and activation energy.

Ionomer Design, Synthesis and Characterization for Ion-Conducting Energy Materials

NASA Astrophysics Data System (ADS)

Colby, Ralph H.

2013-03-01

For ionic actuators and battery separators, it is vital to utilize single-ion conductors that avoid the detrimental polarization of other ions; the commonly studied dual-ion conductors simply will not be used in the next generation of materials for these applications. Ab initio quantum chemistry calculations at 0 K in vacuum characterize ion interactions and ion solvation by various functional groups, allowing identification of constituents with weak interactions to be incorporated in ionomers for facile ion transport. Simple ideas for estimating the ion interactions and solvation at practical temperatures and dielectric constants are presented that indicate the rank ordering observed at 0 K in vacuum should be preserved. Hence, such ab initio calculations are useful for screening the plethora of combinations of polymer-ion, counterion and polar functional groups, to decide which are worthy of synthesis for new ionomers. Single-ion conducting ionomers are synthesized based on these calculations, with low glass transition temperatures (facile dynamics) to prepare ion-conducting membranes for ionic actuators and battery separators. Characterization by X-ray scattering, dielectric spectroscopy, NMR and linear viscoelasticity collectively develop a coherent picture of ionic aggregation and both counterion and polymer dynamics. Examples are shown of how ab initio calculations can be used to understand experimental observations of dielectric constant, glass transition temperature and conductivity of polymerized ionic liquids with counterions being either lithium, sodium, fluoride, hydroxide (for batteries) or bulky ionic liquids (for ionic actuators). This work was supported by the Department of Energy under Grant BES-DE-FG02-07ER46409.

Fast Li-Ion Transport in Amorphous Li 2Si 2O 5: An Ab Initio Molecular Dynamics Simulation

DOE PAGES

Lei, Xueling; Wang, Jie; Huang, Kevin

2016-05-03

The present study reports an ab-initio molecular dynamics (AIMD) simulation of ionic diffusion in the amorphous Li 2Si 2O 5 in a temperature range of 573–823 K. The results show that the amorphous Li 2Si 2O 5 is primarily a Li + conductor with negligible O 2- and Si 4+ contributions. The obtained activation energy of 0.47 eV for Li + diffusion is higher than Na + in the analogue amorphous Na 2Si 2O 5, but close to other types of Li + conductors. The predicted Li + conductivity is on the order of 10 -2 S·cm -1 at 623–823more » K. Our simulations also reveal that Li + in the amorphous Li 2Si 2O 5 diffuses via a hopping mechanism between the nearest sites in the channels formed by two adjacent SiO 4 layers.« less

Humidity Effect on Nanoscale Electrochemistry in Solid Silver Ion Conductors and the Dual Nature of Its Locality

DOE PAGES

Yang, Sangmo; Strelcov, Evgheni; Paranthaman, Mariappan Parans; ...

2015-01-07

Scanning probe microscopy (SPM) is a powerful tool to investigate electrochemistry in nanoscale volumes. While most SPM-based studies have focused on reactions at the tip-surface junction, charge and mass conservation requires coupled and intrinsically non-local cathodic and anodic processes that can be significantly affected by ambient humidity. Here, we explore the role of water in both cathodic and anodic processes, associated charge transport, and topographic volume changes depending on the polarity of tip bias. The first-order reversal curve current-voltage technique combined with simultaneous detection of the sample topography, referred to as FORC-IVz, was applied to a silver solid ion conductor.more » We found that the protons generated from water affect silver ionic conduction, silver particle formation and dissolution, and mechanical integrity of the material. This work highlights the dual nature (simultaneously local and non-local) of electrochemical SPM studies, which should be considered for comprehensive understanding of nanoscale electrochemistry.« less

Humidity effect on nanoscale electrochemistry in solid silver ion conductors and the dual nature of its locality.

PubMed

Yang, Sang Mo; Strelcov, Evgheni; Paranthaman, M Parans; Tselev, Alexander; Noh, Tae Won; Kalinin, Sergei V

2015-02-11

Scanning probe microscopy (SPM) is a powerful tool to investigate electrochemistry in nanoscale volumes. While most SPM-based studies have focused on reactions at the tip-surface junction, charge and mass conservation requires coupled and intrinsically nonlocal cathodic and anodic processes that can be significantly affected by ambient humidity. Here, we explore the role of water in both cathodic and anodic processes, associated charge transport, and topographic volume changes depending on the polarity of tip bias. The first-order reversal curve current-voltage technique combined with simultaneous detection of the sample topography, referred to as FORC-IVz, was applied to a silver solid ion conductor. We found that the protons generated from water affect silver ionic conduction, silver particle formation and dissolution, and mechanical integrity of the material. This work highlights the dual nature (simultaneously local and nonlocal) of electrochemical SPM studies, which should be considered for comprehensive understanding of nanoscale electrochemistry.

Mixed protonic and electronic conductors hybrid oxide synaptic transistors

NASA Astrophysics Data System (ADS)

Fu, Yang Ming; Zhu, Li Qiang; Wen, Juan; Xiao, Hui; Liu, Rui

2017-05-01

Mixed ionic and electronic conductor hybrid devices have attracted widespread attention in the field of brain-inspired neuromorphic systems. Here, mixed protonic and electronic conductor (MPEC) hybrid indium-tungsten-oxide (IWO) synaptic transistors gated by nanogranular phosphorosilicate glass (PSG) based electrolytes were obtained. Unique field-configurable proton self-modulation behaviors were observed on the MPEC hybrid transistor with extremely strong interfacial electric-double-layer effects. Temporally coupled synaptic plasticities were demonstrated on the MPEC hybrid IWO synaptic transistor, including depolarization/hyperpolarization, synaptic facilitation and depression, facilitation-stead/depression-stead behaviors, spiking rate dependent plasticity, and high-pass/low-pass synaptic filtering behaviors. MPEC hybrid synaptic transistors may find potential applications in neuron-inspired platforms.

Study, selection, and preparation of solid cationic conductors

NASA Technical Reports Server (NTRS)

Roth, W. L.; Mitoff, S. P.; King, R. N.

1972-01-01

Crystal chemical principles and transport theory were used to predict structures and specific compounds which might find application as solid electrolytes in rechargeable high energy and high power density batteries operating at temperatures less than 200 C. More than twenty compounds were synthesized or obtained and screened by nuclear magnetic resonance and conductivity. Many were densified by sintering or hot pressing. Encouraging results were obtained for nine of these materials but none have yet been good ionic conductors at low temperature.

Research@ARL: Materials Modeling at Multiple Scales. Volume 3, Issue 2

DTIC Science & Technology

2014-07-01

possessing high ionic conductivity , low viscosity, and good thermal and electrochemical stability and, importantly, being compatible with electrodes. As... thermal and electrical properties. ARL conducts extensive research in graphene and other 2D materials such as BN, ZnO, and hybrid graphene-polyethylene...contribution at temperatures below 393 K. Thus, below 393 K, Li2EDC essentially acts as a single ion conductor . The isotropic ionic conductivity from MD

Conductivities of the ionic complexes of two cyclic polyethers

NASA Technical Reports Server (NTRS)

Fielder, W. L.; Odonnell, P. M.

1975-01-01

The conductivities of the solid potassium thiocyanate complex of both dicyclohexyl-18-crown-6 and dibenzo-18-crown-6 were measured at 300K (27 C). Saturated aqueous potassium thiocyanate and graphite were used as ion-transporting and ion-blocking electrodes, respectively. The ionic conductivity predominated for both samples, but it was many orders of magnitude smaller than the value previously reported. The ionic conductivity of the dicyclohexyl complex (the better conductor) was 0.000003 ohm/cm. Crown complexes, in general, do not appear promising as potassium ion solid electrolytes contrary to claims in the patent literature.

Role of salt concentration in blend polymer for energy storage conversion devices

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

Arya, Anil; Sharma, A. L., E-mail: alsharmaiitkgp@gmail.com; Sadiq, M.

2016-05-06

Solid Polymer Electrolytes (SPE) are materials of considerable interest worldwide, which serves dual purpose of electrolyte and separator between electrode compartments in renewable energy conversion/storage devices such as; high energy density batteries, electrochromic display devices, and supercapacitors. Polymer blend electrolytes are prepared for various concentration of salt (Ö/Li) with the constant ratio (0.5 gm) of each PEO and PAN polymers (blend polymer) using solution casting technique. Solid polymeric ionic conductor as a separator is the ultimate substitute to eliminate the drawback related to liquid and gel polymer ionic conductors. In the present work, solid polymer electrolyte film consisting of PEO,more » PAN and LiPF{sub 6} are examined for various concentration of lithium salt by keeping PEO/PAN blend ratio as a constant with a view to optimize the dominant salt concentration which could give the maximum conductivity at ambient temperature.« less

Communication: Dimensionality of the ionic conduction pathways in glass and the mixed-alkali effect.

PubMed

Novy, Melissa; Avila-Paredes, Hugo; Kim, Sangtae; Sen, Sabyasachi

2015-12-28

A revised empirical relationship between the power law exponent of ac conductivity dispersion and the dimensionality of the ionic conduction pathway is established on the basis of electrical impedance spectroscopic (EIS) measurements on crystalline ionic conductors. These results imply that the "universal" ac conductivity dispersion observed in glassy solids is associated with ionic transport along fractal pathways. EIS measurements on single-alkali glasses indicate that the dimensionality of this pathway D is ∼2.5, while in mixed-alkali glasses, D is lower and goes through a minimum value of ∼2.2 when the concentrations of the two alkalis become equal. D and σ display similar variation with alkali composition, thus suggesting a topological origin of the mixed-alkali effect.

Impact of gate geometry on ionic liquid gated ionotronic systems

DOE PAGES

Wong, Anthony T.; Noh, Joo Hyon; Pudasaini, Pushpa Raj; ...

2017-01-23

Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard “side gate” 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. Finally, these findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

Predictive model for ionic liquid extraction solvents for rare earth elements

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

Grabda, Mariusz; Oleszek, Sylwia; Institute of Environmental Engineering of the Polish Academy of Sciences, ul. M. Sklodowskiej-Curie 34, 41-819, Zabrze

2015-12-31

The purpose of our study was to select the most effective ionic liquid extraction solvents for dysprosium (III) fluoride using a theoretical approach. Conductor-like Screening Model for Real Solvents (COSMO-RS), based on quantum chemistry and the statistical thermodynamics of predefined DyF{sub 3}-ionic liquid systems, was applied to reach the target. Chemical potentials of the salt were predicted in 4,400 different ionic liquids. On the base of these predictions set of ionic liquids’ ions, manifesting significant decrease of the chemical potentials, were selected. Considering the calculated physicochemical properties (hydrophobicity, viscosity) of the ionic liquids containing these specific ions, the most effectivemore » extraction solvents for liquid-liquid extraction of DyF{sub 3} were proposed. The obtained results indicate that the COSMO-RS approach can be applied to quickly screen the affinity of any rare earth element for a large number of ionic liquid systems, before extensive experimental tests.« less

A Na+ Superionic Conductor for Room-Temperature Sodium Batteries

NASA Astrophysics Data System (ADS)

Song, Shufeng; Duong, Hai M.; Korsunsky, Alexander M.; Hu, Ning; Lu, Li

2016-08-01

Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10-3 S cm-1. We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor.

A Na+ Superionic Conductor for Room-Temperature Sodium Batteries

PubMed Central

Song, Shufeng; Duong, Hai M.; Korsunsky, Alexander M.; Hu, Ning; Lu, Li

2016-01-01

Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10−3 S cm−1. We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor. PMID:27572915

A Na(+) Superionic Conductor for Room-Temperature Sodium Batteries.

PubMed

Song, Shufeng; Duong, Hai M; Korsunsky, Alexander M; Hu, Ning; Lu, Li

2016-08-30

Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10(-3) S cm(-1). We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor.

Density Optimization of Lithium Lanthanum Titanate Ceramics for Lightweight Lithium-Air Batteries

DTIC Science & Technology

2014-11-01

Thangadurai V, Weppner W. Lithium lanthanum titanates: a review. Chemistry of Materials. 2003;15:3974–3990. 4. Knauth P. Inorganic solid Li ion conductors...an overview. Solid State Ionics. 2009;180:911–916. 5. Ban CW, Choi GM. The effect of sintering on the grain boundary conductivity of lithium ...lanthanum titanates. Solid State Ionics. 2001;140:285–292. 6. Inada R, Kimura K, Kusakabe K, Tojo T, Sakurai Y. Synthesis and lithium -ion conductivity

Perfluoroalkyl phosphonic and phosphinic acids as proton conductors for anhydrous proton-exchange membranes.

PubMed

Herath, Mahesha B; Creager, Stephen E; Kitaygorodskiy, Alex; DesMarteau, Darryl D

2010-09-10

A study of proton-transport rates and mechanisms under anhydrous conditions using a series of acid model compounds, analogous to comb-branch perfluorinated ionomers functionalized with phosphonic, phosphinic, sulfonic, and carboxylic acid protogenic groups, is reported. Model compounds are characterized with respect to proton conductivity, viscosity, proton, and anion (conjugate base) self-diffusion coefficients, and Hammett acidity. The highest conductivities, and also the highest viscosities, are observed for the phosphonic and phosphinic acid model compounds. Arrhenius analysis of conductivity and viscosity for these two acids reveals much lower activation energies for ion transport than for viscous flow. Additionally, the proton self-diffusion coefficients are much higher than the conjugate-base self-diffusion coefficients for these two acids. Taken together, these data suggest that anhydrous proton transport in the phosphonic and phosphinic acid model compounds occurs primarily by a structure-diffusion, hopping-based mechanism rather than a vehicle mechanism. Further analysis of ionic conductivity and ion self-diffusion rates by using the Nernst-Einstein equation reveals that the phosphonic and phosphinic acid model compounds are relatively highly dissociated even under anhydrous conditions. In contrast, sulfonic and carboxylic acid-based systems exhibit relatively low degrees of dissociation under anhydrous conditions. These findings suggest that fluoroalkyl phosphonic and phosphinic acids are good candidates for further development as anhydrous, high-temperature proton conductors.

Hybrid graphene/geopolymeric cement as a superionic conductor for structural health monitoring applications

NASA Astrophysics Data System (ADS)

Saafi, M.; Piukovics, G.; Ye, J.

2016-10-01

In this paper, we demonstrate for the first time a novel hybrid superionic long gauge sensor for structural health monitoring applications. The sensor consists of two graphene electrodes and a superionic conductor film made entirely of fly ash geopolymeric material. The sensor employs ion hopping as a conduction mechanism for high precision temperature and tensile strain sensing in structures. The design, fabrication and characterization of the sensor are presented. The temperature and strain sensing mechanisms of the sensor are also discussed. The experimental results revealed that the crystal structure of the superionic film is a 3D sodium-poly(sialate-siloxo) framework, with a room temperature ionic conductivity between 1.54 × 10-2 and 1.72 × 10-2 S m-1 and, activation energy of 0.156 eV, which supports the notion that ion hopping is the main conduction mechanism for the sensor. The sensor showed high sensitivity to both temperature and tensile strain. The sensor exhibited temperature sensitivity as high as 21.5 kΩ °C-1 and tensile strain sensitivity (i.e., gauge factor) as high as 358. The proposed sensor is relatively inexpensive and can easily be manufactured with long gauges to measure temperature and bulk strains in structures. With further development and characterization, the sensor can be retrofitted onto existing structures such as bridges, buildings, pipelines and wind turbines to monitor their structural integrity.

[Ionic liquid based ultrasonication-assisted extraction of essential oil from the leaves of Persicaria minor and conductor-like screening model for realistic solvents study].

PubMed

Habib, Ullah; Cecilia, D Wilfred; Maizatul, S Shaharun

2017-06-08

Ionic liquids (ILs) based ultrasonic-assisted extract has been applied for the extraction of essential oil from Persicaria minor leaves. The effects of temperature, sonication time, and particle size of the plant material on the yield of essential oil were investigated. Among the different ILs employed, 1-ethyl-3-methylimidazolium acetate was the most effective, providing a 9.55% yield of the essential oil under optimum conditions (70 ℃, 25 min, IL:hexane ratio of 7:10 (v/v), particle size 60-80 mesh). The performance of 1-ethyl-3-methylimidazolium acetate in the extraction was attributed to its low viscosity and ability to disintegrate the structural matrix of the plant material. The ability of 1-ethyl-3-methylimidazolium acetate was also confirmed using the conductor like-screening model for realistic solvents. This research proves that ILs can be used to extract essential oils from lignocellulosic biomass.

Deposition of Composite LSCF-SDC and SSC-SDC Cathodes by Axial-Injection Plasma Spraying

NASA Astrophysics Data System (ADS)

Harris, Jeffrey; Qureshi, Musab; Kesler, Olivera

2012-06-01

The performance of solid oxide fuel cell cathodes can be improved by increasing the number of electrochemical reaction sites, by controlling microstructures, or by using composite materials that consist of an ionic conductor and a mixed ionic and electronic conductor. LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ) and SSC (Sm0.5Sr0.5CoO3) cathodes were manufactured by axial-injection atmospheric plasma spraying, and composite cathodes were fabricated by mixing SDC (Ce0.8Sm0.2O1.9) into the feedstock powders. The plasma power was varied by changing the proportion of nitrogen in the plasma gas. The microstructures of cathodes produced with different plasma powers were characterized by scanning electron microscopy and gas permeation measurements. The deposition efficiencies of these cathodes were calculated based on the mass of the sprayed cathode. Particle surface temperatures were measured in-flight to enhance understanding of the relationship between spray parameters, microstructure, and deposition efficiency.

Nonlinear ionic transport through microstructured solid electrolytes: homogenization estimates

NASA Astrophysics Data System (ADS)

Curto Sillamoni, Ignacio J.; Idiart, Martín I.

2016-10-01

We consider the transport of multiple ionic species by diffusion and migration through microstructured solid electrolytes in the presence of strong electric fields. The assumed constitutive relations for the constituent phases follow from convex energy and dissipation potentials which guarantee thermodynamic consistency. The effective response is heuristically deduced from a multi-scale convergence analysis of the relevant field equations. The resulting homogenized response involves an effective dissipation potential per species. Each potential is mathematically akin to that of a standard nonlinear heterogeneous conductor. A ‘linear-comparison’ homogenization technique is then used to generate estimates for these nonlinear potentials in terms of available estimates for corresponding linear conductors. By way of example, use is made of the Maxwell-Garnett and effective-medium linear approximations to generate estimates for two-phase systems with power-law dissipation. Explicit formulas are given for some limiting cases. In the case of threshold-type behavior, the estimates exhibit non-analytical dilute limits and seem to be consistent with fields localized in low energy paths.

Interfacial behaviours between lithium ion conductors and electrode materials in various battery systems

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

Wu, Bingbin; Wang, Shanyu; Evans IV, Willie J.

In recent years room temperature Li+ ion conductors have been intensively revisited in order to develop safe lithium ion (Li-ion) batteries and beyond that can be deployed in the electrical vehicles. Through careful modification on materials synthesis, promising solid Li+ conductors with high ionic conductivity, competitve with liquid electrolytes, have been demonstrated. However, the integration of those highly conductive solid electrolytes into the whole system is still very challenging mainly due to the high impedance existing in the different interfaces throughout the entire battery structure. Herein , this review paper focuses on the overview of the interfacial behaviors between Li+more » conductors and cathode/anode materials. The origin, evolution and potential solutions to reuce these interfacial impedances are reviewed for various battery systems spanning from Li-ion, lithium sulfur (Li-S), lithium oxygen (Li-O2) batteries to lithium metal protection. The predicted gravimetric and volumetric energy densities at different scenarios are also discussed along with the prospectives for further development of solid state batteries.« less

Electronic ferroelectricity in carbon-based systems: from reality of organic conductors to promises of polymers and graphene nano-ribbons

NASA Astrophysics Data System (ADS)

Kirova, Natasha; Brazovskii, Serguei

2014-03-01

Ferroelectricity is a rising demand in fundamental and applied solid state physics. Ferroelectrics are used in microelectronics as active gate materials, in capacitors, electro-optical-acoustic modulators, etc. There is a particular demand for plastic ferroelectrics, e.g. as a sensor for acoustic imaging in medicine and beyond, in shapeable capacitors, etc. Microscopic mechanisms of ferroelectric polarization in traditional materials are typically ionic. In this talk we discuss the electronic ferroelectrics - carbon-based materials: organic crystals, conducting polymers and graphene nano-ribbons. The motion of walls, separating domains with opposite electric polarisation, can be influenced and manipulated by terahertz and infra-red range optics.

Vapour growth of argyrodite-type ionic conductors Cu 6PS 5Hal

NASA Astrophysics Data System (ADS)

Fiechter, S.; Eckstein, J.; Nitsche, R.

1983-03-01

Cu 6PS 5Hal compounds (with Hal = Cl, Br or I) have been crystallized around 950 K by CVT with P, S and Hal (and combinations thereof). Chemical insight into the transport processes was gained from dissociation pressure measurements and spectroscopic vapour analysis. Lacking thermochemical data of the compounds were obtained from Cp measurements. Models, derived for the CVT mechanisms, yield transport rates and directions which agree qualitatively with experiments. The main vapour species (for Hal = C1) are PSCI 3, S 2, PCI 3, P 4S 3 and (CuCl) 3. With a surplus of CuHal, VLS growth via liquid CuHal/Cu 2S phases was observed.

Characterization of chitosan-starch blend based biopolymer electrolyte doped with ammonium nitrate

NASA Astrophysics Data System (ADS)

Shaffie, Ahmad Hakimi; Khiar, Azwani Sofia Ahmad

2018-06-01

Polymer electrolyte is an ionic conductor formed by dissolving salt in polymer host. In this work, starch/chitosan blend based polymer electrolyte was prepared with different weight percentage of Ammonium Nitrate (NH4NO3) via solution casting technique. The film was characterized by impedance spectroscopy HIOKI 3531- 01 LCR Hi-Tester to measure its ionic conductivity over a wide range of frequency between 50Hz-5MHz and at ambient temperature. Sample with 35 wt% of NH4NO3 shows the highest conductivity of (6.34 ± 1.52) = 10-7 Scm-1. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used to correlate the ionic conductivity results.

Experiments in Ice Physics.

ERIC Educational Resources Information Center

Martin, P. F.; And Others

1978-01-01

Describes experiments in ice physics that demonstrate the behavior and properties of ice. Show that ice behaves as an ionic conductor in which charge is transferred by the movement of protons, its electrical conductivity is highly temperature-dependent, and its dielectric properties show dramatic variation in the kilohertz range. (Author/GA)

AC loss, interstrand resistance and mechanical properties of prototype EU DEMO TF conductors up to 30 000 load cycles

NASA Astrophysics Data System (ADS)

Yagotintsev, K.; Nijhuis, A.

2018-07-01

Two prototype Nb3Sn cable-in-conduit conductors conductors were designed and manufactured for the toroidal field (TF) magnet system of the envisaged European DEMO fusion reactor. The AC loss, contact resistance and mechanical properties of two sample conductors were tested in the Twente Cryogenic Cable Press under cyclic load up to 30 000 cycles. Though both conductors were designed to operate at 82 kA in a background magnetic field of 13.6 T, they reflect different approaches with respect to the magnet winding pack assembly. The first approach is based on react and wind technology while the second is the more common wind and react technology. Each conductor was tested first for AC loss in virgin condition without handling. The impact of Lorentz load during magnet operation was simulated using the cable press. In the press each conductor specimen was subjected to transverse cyclic load up to 30 000 cycles in liquid helium bath at 4.2 K. Here a summary of results for AC loss, contact resistance, conductor deformation, mechanical heat production and conductor stiffness evolution during cycling of the load is presented. Both conductors showed similar mechanical behaviour but quite different AC loss. In comparison with previously tested ITER TF conductors, both DEMO TF conductors possess very low contact resistance resulting in high coupling loss. At the same time, load cycling has limited impact on properties of DEMO TF conductors in comparison with ITER TF conductors.

Search for solid conductors of Na(+) and K(+) ions: Five new conductors

NASA Technical Reports Server (NTRS)

Singer, J.; Kautz, H.; Fielder, W. L.; Fordyce, J.

1975-01-01

Five conductors of three structure types were discovered which, as solids, can transport Na(+) or K(+) ions with conductivities of approximately .00001/(omega cm) at 300 K. These compounds are: (1) the pyrochlores NaTaWO6 and NaTa2O5F, both with an activation energy for conduction delta E of 21 kJ/mole; (2) the bodycentered cubic form of NaSbO3, with delta E = 42 kJ/mole; and (3) the niobates 2Na2O with 3Nb2O5 and 2K2O with 3Nb2O5, with the alkali ions probably in open layers of the incompletely determined structure; delta E = 17 kJ/mole. On the basis of approximately 40 structure types, some generalizations were made regarding the relation between structure and ionic transport.

Interconnected ionic domains enhance conductivity in microphase separated block copolymer electrolytes

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

Arges, Christopher G.; Kambe, Yu; Dolejsi, Moshe

Block copolymer electrolytes (BCEs) represent an attractive choice as solid-state ionic conductors for electrochemical technologies used in energy storage and conversion, water treatment, sensors, and data storage and processing. Unlocking the maximum ionic conductivity of BCEs requires an intimate understanding as to how the microphase separated structure influences transport properties. However, elucidating such knowledge remains elusive due to the challenging task of precisely engineering BCEs with a defined structure in bulk materials. In this work, we examined BCEs in a thin film format because it was amenable to attaining BCEs with a desired nanostructure. Specifically, we systematically investigated anion-conducting BCEsmore » with different degrees of connectivity of the ionic domains. For the first time, we demonstrate that increasing terminal defects in the ionic domain from 1 terminal defect per mu m(2) to 20 terminal defects per mu m(2) ( a relatively small amount of defects) decreased ionic conductivity by 67% compared to the maximum value attained. Conversely, maximizing ionic domain connectivity increased the ionic conductivity by two-fold over a non-ordered BCE film. These experiments highlight that microphase separation alone was insufficient for ameliorating ionic conductivity in BCEs. Rather, microphase separation coupled with complete ionic domain connectivity realized BCEs with significantly enhanced ionic conductivity.« less

Enhanced Mixed Electronic-Ionic Conductors through Cation Ordering

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

Jacobson, Allan J.; Morgan, Dane; Grey, Clare

2014-08-31

The performance of many energy conversion and storage devices depend on the properties of mixed ionic-electronic conducting (miec) materials. Mixed or ambipolar conductors simultaneously transport ions and electrons and provide the critical interface between chemical and electrical energy in devices such as fuel cells, ion transport membranes, and batteries. Enhancements in storage capacity, reversibility, power density and device lifetime all require new materials and a better understanding of the fundamentals of ambipolar conductivity and surface reactivity.The high temperature properties of the ordered perovksites AA’B 2O 5+x, where A = rare earth ion, Y and B = Ba, Sr were studied.more » The work was motivated by the high oxygen transport and surface exchange rates observed for members of this class of mixed ionic and electronic conductors. A combined experimental and computational approach, including structural, electrochemical, and transport characterization and modeling was used. The approach attacks the problem simultaneously at global (e.g., neutron diffraction and impedance spectroscopy), local (e.g., pair distribution function, nuclear magnetic resonance) and molecular (ab initio thermokinetic modeling) length scales. The objectives of the work were to understand how the cation and associated anion order lead to exceptional ionic and electronic transport properties and surface reactivity in AA’B2O5+x perovskites. A variety of compounds were studied by X-ray and neutron diffraction, measurements of thermodynamics and transport and theoretically. These included PrBaCo 2O 5+x and NdBaCo 2O 5+x, PrBaCo 2-xFexO 6- δ (x = 0, 0.5, 1.0, 1.5 and 2) and LnBaCoFeO 6- δ (Ln = La, Pr, Nd, Sm, Eu and Gd), Sr 3YCo 4O 10.5, YBaMn 2O 5+x. A 0.5A’ 0.5BO 3 (where A=Y, Sc, La, Ce, Pr, Nd, Pm, Sm; A’= Sr, Ba; and B= Fe, Co, Mn, Ni), Ba 2In 2O 5, and La 1 xSr xCoO 3-δ /(La 1-ySry) 2CoO 4±δ interfaces.« less

Solid State Ionic Materials - Proceedings of the 4th Asian Conference on Solid State Ionics

NASA Astrophysics Data System (ADS)

Chowdari, B. V. R.; Yahaya, M.; Talib, I. A.; Salleh, M. M.

1994-07-01

The Table of Contents for the full book PDF is as follows: * Preface * I. INVITED PAPERS * Diffusion of Cations and Anions in Solid Electrolytes * Silver Ion Conductors in the Crystalline State * NMR Studies of Superionic Conductors * Hall Effect and Thermoelectric Power in High Tc Hg-Ba-Ca-Cu-O Ceramics * Solid Electrolyte Materials Prepared by Sol-Gel Chemistry * Preparation of Proton-Conducting Gel Films and their Application to Electrochromic Devices * Thin Film Fuel Cells * Zirconia based Solid Oxide Ion Conductors in Solid Oxide Fuel Cells * The Influence of Anion Substitution on Some Phosphate-based Ion Conducting Glasses * Lithium Intercalation in Carbon Electrodes and its Relevance in Rocking Chair Batteries * Chemical Sensors using Proton Conducting Ceramics * NMR/NQR Studies of Y-Ba-Cu-O Superconductors * Silver Molybdate Glasses and Battery Systems * New Highly Conducting Polymer Ionics and their Application in Electrochemical Devices * Study of Li Electrokinetics on Oligomeric Electrolytes using Microelectrodes * Calculation of Conductivity for Mixed-Phase Electrolytes PEO-MX-Immiscible Additive by Means of Effective Medium Theory * II. CONTRIBUTED PAPERS * Phase Relationship and Electrical Conductivity of Sr-V-O System with Vanadium Suboxide * Amorphous Li+ Ionic Conductors in Li2SO4-Li2O-P2O5 System * Fast Ion Transport in KCl-Al2O3 Composites * The Effect of the Second Phase Precipitation on the Ionic Conductivity of Zr0.85Mg0.15O1.85 * Conductivity Measurements and Phase Relationships in CaCl2-CaHCl Solid Electrolyte * Relationships Between Crystal Structure and Sodium Ion Conductivity in Na7Fe4(AsO4)6 and Na3Al2(AsO4)3 * Electrical Conductivity and Solubility Limit of Ti4+ Ion in Na1+x TiyZr2-ySixP3-xO12 System * Study on Sodium Fast Ion Conductors of Na1+3xAlxTi2-xSi2xP3-2xO12 System * Influences of Zirconia on the Properties of β''-Alumina Ceramics * Decay of Luminescence from Cr3+ Ions in β-Alumina * Lithium Ion Conductivity in the Li4XO4-Li2SO4 (X=Si, Ge, Ti) Systems * A DSC and Conductivity Study of the Influence of Cesium Ion on the Beta-Alpha Transition in Silver Iodide * Phase Diagrams, Stoichiometries and Properties of Bi4V2O11:M2+ Solid Electrolytes * Physical Properties of Electrodeposited Silver Chromotungstate * Pseudopotential Study of Bonding in the Superionic Material AgI: The Effect of Statistical Distribution of Mobile Ions * Cubic Phase Dominant Region in Submicron BaTiO3 Particles * The Crystallization of CoZr Amorphous Alloys via Electrical Resistivity * Cation Ratio Related Properties of Synthetic Mg/Al Layered Double Hydroxide and it's Nanocomposite * DC Conductivity of Nano-Particles of Silver Iodide * Effect of Anomalous Diffusion on Quasielastic Scattering in Superionic Conductors * Computer Simulation Study of Conductivity Enhancement in Superionic-Insulator Composites * Dynamics of Superionic Silver and Copper Iodide Salt Melts * Influence of Dopant Salt AgI, Glass Modifier Ag2O and Glass Formers (SeO3 + MoO3) on Electrical Conductivity in Quaternary Glassy System * Fast Ion Conductivity in the Presence of Competitive Network Formers * Role of Alkali Ions in Borate Glasses * Inelastic Light Scattering in Cadmium Borate Glasses * Investigation on Transport Properties of Mixed Glass System 0.75 [0.75AgI:0.25AgCl]. 0.25[Ag2O:CrO3] * Conduction Mechanism in Lithium Tellurite Glasses * Optimized Silver Tungstoarsenate Glass Electrolyte * Stabilized Superfine Zirconia Powder Prepared by Sol-Gel Process * Study of New PAN-based Electrolytes * Electrical and Thermal Characterization of PVA based Polymer Electrolytes * Conductive Electroactive Polymers: Versatile Solid State Ionic Materials * The Role of Ag2O Addition on the Superconducting Properties of Y-124 Compound * Absorption Spectra Studies of the C60 Films on Transition Metal Film Substrates * Effect of Alumina Dispersal on the Conductivity and Crystallite Size of Polymer Electrolyte * New Mixed Galss-Polymer Solid Electrolytes * The Sputtered La0.5Sr0.5MnO3-Yttria Stabilized Zirconia Composite Electrode in Solid Oxide Fuel Cells * A Solid Electrochemical Ferro Sensor for Molten Matte * SnO2-based Sensor for H2S Monitoring-Electrical Conductivity Measurements and Device Testing * Humidity Sensor using Potassium Tungsten Bronze Synthesized from Peroxo-Polytungstic Acid * Study on Li/LiClO4/V6O13 Test Cells * Fabrication and Characterisation of Some Solid Electrolyte Cells Containing CuI and Silver Oxysalts * Solid State Battery of Proton Conducting Sodium Thiosulphate Pentahydrate * Low Temperature Synthesis of LiMn2O4 for Secondary Lithium Batteries * Effect of Different Cathode Active Materials on Battery Performance with Silver Molybdate Electrolyte Partially Substituted with Zinc Oxide * Fabrication and Characterization of Electrochemical Cells based on Silver Molybdoarsenate and Silver Tungstoarsenate Glass Electrolytes * Lorentz Force Dependence of Dissipation in a Granular Superconductor * Late Entry (Invited paper) * Simultaneous Voltammetry and Spectroscopy of Polyaniline in Propylene Carbonate * Author Index * Tentative List of Participants

Sodium Ion Diffusion in Nasicon (Na3Zr2Si2PO12) Solid Electrolytes: Effects of Excess Sodium.

PubMed

Park, Heetaek; Jung, Keeyoung; Nezafati, Marjan; Kim, Chang-Soo; Kang, Byoungwoo

2016-10-04

The Na superionic conductor (aka Nasicon, Na 1+x Zr 2 Si x P 3-x O 12 , where 0 ≤ x ≤ 3) is one of the promising solid electrolyte materials used in advanced molten Na-based secondary batteries that typically operate at high temperature (over ∼270 °C). Nasicon provides a 3D diffusion network allowing the transport of the active Na-ion species (i.e., ionic conductor) while blocking the conduction of electrons (i.e., electronic insulator) between the anode and cathode compartments of cells. In this work, the standard Nasicon (Na 3 Zr 2 Si 2 PO 12 , bare sample) and 10 at% Na-excess Nasicon (Na 3.3 Zr 2 Si 2 PO 12 , Na-excess sample) solid electrolytes were synthesized using a solid-state sintering technique to elucidate the Na diffusion mechanism (i.e., grain diffusion or grain boundary diffusion) and the impacts of adding excess Na at relatively low and high temperatures. The structural, thermal, and ionic transport characterizations were conducted using various experimental tools including X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). In addition, an ab initio atomistic modeling study was carried out to computationally examine the detailed microstructures of Nasicon materials, as well as to support the experimental observations. Through this combination work comprising experimental and computational investigations, we show that the predominant mechanisms of Na-ion transport in the Nasicon structure are the grain boundary and the grain diffusion at low and high temperatures, respectively. Also, it was found that adding 10 at% excess Na could give rise to a substantial increase in the total conductivity (e.g., ∼1.2 × 10 -1 S/cm at 300 °C) of Nasicon electrolytes resulting from the enlargement of the bottleneck areas in the Na diffusion channels of polycrystalline grains.

Fundamentals of ionic conductivity relaxation gained from study of procaine hydrochloride and procainamide hydrochloride at ambient and elevated pressure.

PubMed

Wojnarowska, Z; Swiety-Pospiech, A; Grzybowska, K; Hawelek, L; Paluch, M; Ngai, K L

2012-04-28

The pharmaceuticals, procaine hydrochloride and procainamide hydrochloride, are glass-forming as well as ionically conducting materials. We have made dielectric measurements at ambient and elevated pressures to characterize the dynamics of the ion conductivity relaxation in these pharmaceuticals, and calorimetric measurements for the structural relaxation. Perhaps due to their special chemical and physical structures, novel features are found in the ionic conductivity relaxation of these pharmaceuticals. Data of conductivity relaxation in most ionic conductors when represented by the electric loss modulus usually show a single resolved peak in the electric modulus loss M(")(f) spectra. However, in procaine hydrochloride and procainamide hydrochloride we find in addition another resolved loss peak at higher frequencies over a temperature range spanning across T(g). The situation is analogous to many non-ionic glass-formers showing the presence of the structural α-relaxation together with the Johari-Goldstein (JG) β-relaxation. Naturally the analogy leads us to name the slower and faster processes resolved in procaine hydrochloride and procainamide hydrochloride as the primary α-conductivity relaxation and the secondary β-conductivity relaxation, respectively. The analogy of the β-conductivity relaxation in procaine HCl and procainamide HCl with JG β-relaxation in non-ionic glass-formers goes further by the finding that the β-conductivity is strongly related to the α-conductivity relaxation at temperatures above and below T(g). At elevated pressure but compensated by raising temperature to maintain α-conductivity relaxation time constant, the data show invariance of the ratio between the β- and the α-conductivity relaxation times to changes of thermodynamic condition. This property indicates that the β-conductivity relaxation has fundamental importance and is indispensable as the precursor of the α-conductivity relaxation, analogous to the relation found between the Johari-Goldstein β-relaxation and the structural α-relaxation in non-ionic glass-forming systems. The novel features of the ionic conductivity relaxation are brought out by presenting the measurements in terms of the electric modulus or permittivity. If presented in terms of conductivity, the novel features are lost. This warns against insisting that a log-log plot of conductivity vs. frequency is optimal to reveal and interpret the dynamics of ionic conductors.

Photochemical Hydrogen Doping Induced Embedded Two-Dimensional Metallic Channel Formation in InGaZnO at Room Temperature.

PubMed

Kim, Myeong-Ho; Lee, Young-Ahn; Kim, Jinseo; Park, Jucheol; Ahn, Seungbae; Jeon, Ki-Joon; Kim, Jeong Won; Choi, Duck-Kyun; Seo, Hyungtak

2015-10-27

The photochemical tunability of the charge-transport mechanism in metal-oxide semiconductors is of great interest since it may offer a facile but effective semiconductor-to-metal transition, which results from photochemically modified electronic structures for various oxide-based device applications. This might provide a feasible hydrogen (H)-radical doping to realize the effectively H-doped metal oxides, which has not been achieved by thermal and ion-implantation technique in a reliable and controllable way. In this study, we report a photochemical conversion of InGaZnO (IGZO) semiconductor to a transparent conductor via hydrogen doping to the local nanocrystallites formed at the IGZO/glass interface at room temperature. In contrast to thermal or ionic hydrogen doping, ultraviolet exposure of the IGZO surface promotes a photochemical reaction with H radical incorporation to surface metal-OH layer formation and bulk H-doping which acts as a tunable and stable highly doped n-type doping channel and turns IGZO to a transparent conductor. This results in the total conversion of carrier conduction property to the level of metallic conduction with sheet resistance of ∼16 Ω/□, room temperature Hall mobility of 11.8 cm(2) V(-1) sec(-1), the carrier concentration at ∼10(20) cm(-3) without any loss of optical transparency. We demonstrated successful applications of photochemically highly n-doped metal oxide via optical dose control to transparent conductor with excellent chemical and optical doping stability.

Investigation of ionic transport in sodium scandium phosphate (NSP) and related compounds

NASA Astrophysics Data System (ADS)

Bhat, Kaustubh; Blügel, Stefan; Lustfeld, Hans

Sodium ionic conductors offer significant advantages for application in large scale energy storage systems. In this study, we investigate the different pathways available for sodium ion conduction in NSP and calculate energy barriers for ionic transport using Density Functional Theory (DFT) and the Nudged Elastic Band Method. We identify the structural parameters that reduce the energy barrier, by calculating the influence of positive and negative external pressure on the energy barrier. Lattice strain can be introduced by cation or anion substitution within the NASICON structure. We substitute the scandium atom with other trivalent atoms such as aluminium and yttrium, and calculate the resulting energy barriers. Sodium thiophosphate (Na3PS4) has previously shown about two orders of magnitude higher ionic conductivity than sodium phosphate (Na3PO4). We investigate the effect of substituting oxygen with sulphur in NSP. We acknowledge discussions with our experimental colleagues F. Tietz and M. Guin toward this work

A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3.

PubMed

Li, Ming; Pietrowski, Martha J; De Souza, Roger A; Zhang, Huairuo; Reaney, Ian M; Cook, Stuart N; Kilner, John A; Sinclair, Derek C

2014-01-01

Oxide ion conductors find important technical applications in electrochemical devices such as solid-oxide fuel cells (SOFCs), oxygen separation membranes and sensors. Na0.5Bi0.5TiO3 (NBT) is a well-known lead-free piezoelectric material; however, it is often reported to possess high leakage conductivity that is problematic for its piezo- and ferroelectric applications. Here we report this high leakage to be oxide ion conduction due to Bi-deficiency and oxygen vacancies induced during materials processing. Mg-doping on the Ti-site increases the ionic conductivity to ~0.01 S cm(-1) at 600 °C, improves the electrolyte stability in reducing atmospheres and lowers the sintering temperature. This study not only demonstrates how to adjust the nominal NBT composition for dielectric-based applications, but also, more importantly, gives NBT-based materials an unexpected role as a completely new family of oxide ion conductors with potential applications in intermediate-temperature SOFCs and opens up a new direction to design oxide ion conductors in perovskite oxides.

Performance enhancement of molten carbonate-based direct carbon fuel cell (MC-DCFC) via adding mixed ionic-electronic conductors into Ni anode catalyst layer

NASA Astrophysics Data System (ADS)

Lee, Eun-Kyung; Park, Shin-Ae; Jung, Hyun-Woo; Kim, Yong-Tae

2018-05-01

A high overpotential in the anode of Direct Carbon Fuel Cells (DCFC) is ascribed to the sluggish kinetics of solid fuel oxidation. In this study, we demonstrate a unique approach to enhance the performance of molten-carbonate electrolyte based DCFC (MC-DCFC) by decreasing a serious polarization loss at the anode side; a simple addition of lanthanum strontium cobalt ferrite (LSCF) having a function of mixed ionic-electronic conductors (MIEC) into the Ni anode catalyst layer. Ni:LSCF = 1:1 showed markedly enhanced peak power density of 111 mW/cm2, approximately two-fold higher value than that for the anode using solely Ni and one of the best record in the literature value using carbon black fuel without any contribution of generated syngas oxidation. As can be noted from the electrochemical impedance spectroscopy data, the ohmic and the charge transfer resistance of the anode was markedly decreased owing to the high ionic-electronic conductivity of the MIECs. Furthermore, the enhanced performance can be also attributed to the maximized TPBs (triple phase boundaries) that participate in the carbon oxidation reaction. Based on the results, we suggest that the addition of MIEC materials into the Ni anode catalyst layer is a promising approach to improve the performance of MC-DCFC.

Recent progress on exploring exceptionally high and anisotropic H+/OH– ion conduction in two-dimensional materials

PubMed Central

Sun, Pengzhan; Sasaki, Takayoshi

2017-01-01

Ion conducting membranes/electrolytes have been employed extensively in some important industrial and biological systems, especially in fuel cells, water electrolyzers, gas separation, sensors and biological selective ion transport, acting as one of the core components and sometimes directly determining the device performance. However, the traditional polymeric proton exchange membranes (PEMs)/anion exchange membranes (AEMs) suffer from highly toxic preparation procedures, poor thermal and chemical stabilities, and unsatisfactory ion conductivities. This has triggered researchers worldwide to explore alternative inorganic building blocks with high ion conductivities and stabilities from the new materials library, hoping to solve the above long-lasting problems. The recent burgeoning research on two-dimensional (2D) materials has unveiled exceptionally high ionic conductivities, which raises the feasibility of fabricating high-performance nanosheet-based ion conductors/membranes. In this perspective, the recent advances in measuring and understanding the exceptionally high and anisotropic H+/OH– ion conductivities of representative 2D materials, e.g. graphene oxide (GO), vermiculite and layered double hydroxide (LDH) nanosheets, are reviewed. In particular, regarding the anisotropic ionic conduction in 2D nanosheets, possible design strategies and technological innovations for fabricating macroscopic nanosheet-based ionic conductors/membranes are proposed for maximizing the high in-plane conduction, which may serve to guide future development of high-performance industrial and biological systems relying on H+/OH– conducting membranes. PMID:29629071

Recent progress on exploring exceptionally high and anisotropic H+/OH- ion conduction in two-dimensional materials.

PubMed

Sun, Pengzhan; Ma, Renzhi; Sasaki, Takayoshi

2018-01-07

Ion conducting membranes/electrolytes have been employed extensively in some important industrial and biological systems, especially in fuel cells, water electrolyzers, gas separation, sensors and biological selective ion transport, acting as one of the core components and sometimes directly determining the device performance. However, the traditional polymeric proton exchange membranes (PEMs)/anion exchange membranes (AEMs) suffer from highly toxic preparation procedures, poor thermal and chemical stabilities, and unsatisfactory ion conductivities. This has triggered researchers worldwide to explore alternative inorganic building blocks with high ion conductivities and stabilities from the new materials library, hoping to solve the above long-lasting problems. The recent burgeoning research on two-dimensional (2D) materials has unveiled exceptionally high ionic conductivities, which raises the feasibility of fabricating high-performance nanosheet-based ion conductors/membranes. In this perspective, the recent advances in measuring and understanding the exceptionally high and anisotropic H + /OH - ion conductivities of representative 2D materials, e.g. graphene oxide (GO), vermiculite and layered double hydroxide (LDH) nanosheets, are reviewed. In particular, regarding the anisotropic ionic conduction in 2D nanosheets, possible design strategies and technological innovations for fabricating macroscopic nanosheet-based ionic conductors/membranes are proposed for maximizing the high in-plane conduction, which may serve to guide future development of high-performance industrial and biological systems relying on H + /OH - conducting membranes.

Mixed ionic and electronic conductor based on Sr.sub.2Fe.sub.2-xM0.sub.XO.sub.6 perovskite

DOEpatents

Chen, Fanglin; Liu, Qiang

2014-07-15

In accordance with the present disclosure, a method for fabricating a symmetrical solid oxide fuel cell is described. The method includes synthesizing a composition comprising perovskite and applying the composition on an electrolyte support to form both an anode and a cathode.

Size-Controlled AgI/Ag Heteronanowires in Highly Ordered Alumina Membranes: Superionic Phase Stabilization and Conductivity.

PubMed

Zhang, Hemin; Tsuchiya, Takashi; Liang, Changhao; Terabe, Kazuya

2015-08-12

Nanoscaled ionic conductors are crucial for future nanodevices. A well-known ionic conductor, AgI, exhibited conductivity greater than 1 Ω(-1) cm(-1) in α-phase and transformed into poorly conducting β-/γ-phase below 147 °C, thereby limiting applications. Here, we report that transition temperatures both from the β-/γ- to α-phase (Tc↑) and the α- to β-/γ-phase (Tc↓) are tuned by AgI/Ag heteronanowires embedded in anodic aluminum oxide (AAO) membranes with 10-30 nm pores. Tc↑ and Tc↓ shift to correspondingly higher and lower temperature as pore size decreases, generating a progressively enlarged thermal hysteresis. Tc↑ and Tc↓ specifically achieve 185 and 52 °C in 10 nm pores, and the final survived conductivity reaches ∼8.3 × 10(-3) Ω(-1) cm(-1) at room temperature. Moreover, the low-temperature stabilizing α-phase (down to 21 °C, the lowest in state of the art temperatures) is reproducible and survives further thermal cycling. The low-temperature phase stabilization and enhancement conductivity reported here suggest promising applications in silver-ion-based future nanodevices.

Atomic Scale Picture of the Ion Conduction Mechanism in Tetrahedral Network of Lanthanum Barium Gallate

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

Jalarvo, Niina H; Gourdon, Olivier; Bi, Zhonghe

2013-01-01

Combined experimental study of impedance spectroscopy, neutron powder diffraction and quasielastic neutron scattering was performed to shed light into the atomic scale ion migration processes in proton and oxide ion conductor; La0.8Ba1.2GaO3.9 . This material consist of tetrahedral GaO4 units, which are rather flexible and rocking motion of these units promotes the ionic migration process. The oxide ion (vacancy) conduction takes place on channels along c axis, involving a single elementary step, which occurs between adjacent tetrahedron (inter-tetrahedron jump). The proton conduction mechanism consists of intra-tetrahedron and inter-tetrahedron elementary processes. The intra-tetrahedron proton transport is the rate-limiting process, with activationmore » energy of 0.44 eV. The rocking motion of the GaO4 tetrahedron aids the inter-tetrahedral proton transport, which has the activation energy of 0.068 eV.« less

Ion mobility and transport properties of bismuth fluoride-containing solid solutions with tysonite-type structure

NASA Astrophysics Data System (ADS)

Kavun, V. Ya.; Uvarov, N. F.; Slobodyuk, A. B.; Merkulov, E. B.; Polyantsev, M. M.

2018-07-01

The ion mobility and conductivity of solid solutions with tysonite-type structure obtained by doping bismuth trifluoride with lead (II) fluoride, and zirconium and bismuth oxides have been studied using 19F NMR, X-ray diffraction analysis, and impedance spectroscopy. The types of ionic motions in the fluoride sublattice of the synthesized solid solutions in the temperature range 150-450 K have been determined and the energy of their activation has been estimated. Due to high ionic conductivity, above 10-2 S/cm at 570 K, these solid solutions can be considered as superionic conductors.

Durable electrooptic devices comprising ionic liquids

DOEpatents

Agrawal, Anoop; Cronin, John P.; Tonazzi, Juan C. L.; Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.

2005-11-01

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF3SO3-), bis(trifluoromethylsulfonyl)imide ((CF3SO2)2N-), bis(perfluoroethylsulfonyl)imide ((CF3CF2SO2)2N-) and tris(trifluoromethylsulfonyl)methide ((CF3SO2)3C-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

Synthesis and structure of novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12}

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

Inoue, Yuki; Suzuki, Kota; Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502

The novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12} was synthesized by slow cooling from the ternary Li{sub 2}S–GeS{sub 2}–P{sub 2}S{sub 5} system, and was shown to exhibit a cubic argyrodite-type structure. The phase composition was determined by varying the ratio of starting materials; the observed monophasic properties were close to those for the Li{sub 7}Ge{sub 3}PS{sub 12} composition. The lattice parameter (a =9.80192(3) Å) of Li{sub 7}Ge{sub 3}PS{sub 12} was slightly smaller than that of Li{sub 7}PS{sub 6} (a =9.993 Å), indicating that substitution of a Li cation by the smaller Ge cation contracted the cubic lattice. In addition, themore » novel structure consisted of a framework composed of four isolated (Ge/P)S{sub 4} tetrahedra. Li{sup +} ions occupied tetrahedral sites within the framework, forming a three-dimensional conduction pathway. Finally, Li{sub 7}Ge{sub 3}PS{sub 12} exhibited a high ionic conductivity of 1.1×10{sup −4} S cm{sup −1} at 25 °C and an activation energy of 25 kJ mol{sup −1}. - Graphical abstract: A novel Li{sub 7}Ge{sub 3}PS{sub 12} solid lithium ion conductor, with cubic argyrodite strucuture, shows high ion conductivity of 1.1×10{sup –4} S cm{sup –1} with an activation energy of 25 kJ mol{sup –1}. The argyrodite structure consists of (Ge/P)S{sub 4} tetrahedra units along with partial occupation of lithium and germanium at 48 h site. - Highlights: • A novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12} was detected. • This was achieved through slow cooling of the ternary Li{sub 2}S–GeS{sub 2}–P{sub 2}S{sub 5} system. • This novel conductor revealed a cubic argyrodite-type structure. • Li{sub 7}Ge{sub 3}PS{sub 12} exhibited a high ionic conductivity of 1.1×10{sup −4} S cm{sup −1} at 25 °C. • These properties will aid in the design of superior lithium-ion conductors.« less

Synthesis and characterization of ionomers as polymer electrolytes for energy conversion devices

NASA Astrophysics Data System (ADS)

Oh, Hyukkeun

Single-ion conducting electrolytes present a unique alternative to traditional binary salt conductors used in lithium-ion batteries. Secondary lithium batteries are considered as one of the leading candidates to replace the combustible engines in automotive technology, however several roadblocks are present which prevent their widespread commercialization. Power density, energy density and safety properties must be improved in order to enable the current secondary lithium battery technology to compete with existing energy technologies. It has been shown theoretically that single-ion electrolytes can eliminate the salt concentration gradient and polarization loss in the cell that develops in a binary salt system, resulting in substantial improvements in materials utilization for high power and energy densities. While attempts to utilize single-ion conducting electrolytes in lithium-ion battery systems have been made, the low ionic conductivities prevented the successful operation of the battery cells in ambient conditions. This work focuses on designing single-ion conducting electrolytes with high ionic conductivities and electrochemical and mechanical stability which enables the stable charge-discharge performance of battery cells. Perfluorosulfonate ionomers are known to possess exceptionally high ionic conductivities due to the electron-withdrawing effect caused by the C-F bonds which stabilizes the negative charge of the anion, leading to a large number of free mobile cations. The effect of perfluorinated sulfonic acid side chains on transport properties of proton exchange membrane polymers was examinated via a comparison of three ionomers, having different side chain structures and a similar polymer backbone. The three different side chain structures were aryl-, pefluoro alkyl-, and alkyl-sulfonic acid groups, respectively. All ionomers were synthesized and characterized by 1H and 19F NMR. A novel ionomer synthesized with a pendant perfluorinated sulfonic acid group and a poly(ether ether ketone) backbone showed the highest proton conductivity and proton diffusion coefficient among the three ionomers, demonstrating the effect of the perfluorinated side chains. The proton conductivity of the novel ionomer was comparable to that of Nafion over a wide humidity range and temperature. A lithium perfluorosulfonate ionomer based on aromatic poly(arylene ether)s with pendant lithium perfluoroethyl sulfonates was prepared by ion exchange of the perlfuorosulfonic acid ionomer, and subsequently incoroporated into a lithium-ion battery cell as a single-ion conducting electrolyte. The microporous polymer film saturated with organic carbonates exhibited a nearly unity Li + transfer number, high ionic conductivity (e.g. > 10-3 S m-1 at room temperature) over a wide range of temperatures, high electrochemical stability, and excellent mechanical properties. Excellent cyclability with almost identical charge and discharge capacities have been demonstrated at ambient temperature in the batteries assembled from the prepared single-ion conductors. The mechanical stability of the polymer film was attributed to the rigid polymer backbone which was largely unaffected by the presence of plasticizing organic solvents, while the porous channels with high concentration of the perfluorinated side chains resulted in high ionic conductivity. The expected high charge-rate performance was not achieved, however, due to the high interfacial impedance present between the polymer electrolyte and the electrodes. Several procedural modifications were employed in order to decrease the interfacial impedance of the battery cell. The poly(arylene ether) based ionomer was saturated with an ionic liquid mixture, in order to explore the possibility of its application as a safe, inflammable electrolyte. A low-viscosity ionic liquid with high ionic conductivity, 1-butyl-3-methylimidazolium thiocyanate which has never been successfully utilized as an electrolyte for lithium-ion batteries was incorporated into a battery cell as a solvent mixture with propylene carbonate and lithium bis(trifluoromethane)sulfonimide impregnated in a free-standing hybrid electrolyte film. Outstanding ionic conductivity was achieved and the lithium half cell comprising a LTO cathode and a lithium metal anode separated by the solid polymer electrolyte showed good cyclability at room temperature and even at 0°C. The presence of a sufficient amount of propylene carbonate, which resulted in flammability of the polymer electrolyte, was discovered to be critical in the electrochemical stability of the polymer electrolyte.

30 CFR 57.12004 - Electrical conductors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Electrical conductors. 57.12004 Section 57... Surface and Underground § 57.12004 Electrical conductors. Electrical conductors shall be of a sufficient... operations will not damage the insulating materials. Electrical conductors exposed to mechanical damage shall...

30 CFR 57.12004 - Electrical conductors.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Electrical conductors. 57.12004 Section 57... Surface and Underground § 57.12004 Electrical conductors. Electrical conductors shall be of a sufficient... operations will not damage the insulating materials. Electrical conductors exposed to mechanical damage shall...

30 CFR 57.12004 - Electrical conductors.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Electrical conductors. 57.12004 Section 57... Surface and Underground § 57.12004 Electrical conductors. Electrical conductors shall be of a sufficient... operations will not damage the insulating materials. Electrical conductors exposed to mechanical damage shall...

Proximity and touch sensing using deformable ionic conductors (Conference Presentation)

NASA Astrophysics Data System (ADS)

Madden, John D. W.; Dobashi, Yuta; Sarwar, Mirza S.; Preston, Eden C.; Wyss, Justin K. M.; Woehling, Vincent; Nguyen, Tran-Minh-Giao; Plesse, Cedric; Vidal, Frédéric; Naficy, Sina; Spinks, Geoffrey M.

2017-04-01

There is increasing interest in creating bendable and stretchable electronic interfaces that can be worn or applied to virtually any surface. The electroactive polymer community is well placed to add value by incorporating sensors and actuators. Recent work has demonstrated transparent dielectric elastomer actuation as well as pressure, stretch or touch sensing. Here we present two alternative forms of sensing. The first uses ionically conductive and stretchable gels as electrodes in capacitive sensors that detect finger proximity. In this case the finger acts as a third electrode, reducing capacitance between the two gel electrodes as it approaches, which can be detected even during bending and stretching. Very light finger touch is readily detected even during deformation of the substrate. Lateral resolution is achieved by creating a sensor array. In the second approach, electrodes placed beneath a salt containing gel are able to detect ion currents generated by the deformation of the gel. In this approach, applied pressure results in ion currents that create a potential difference around the point of contact, leading to a voltage and current in the electrodes without any need for input electrical energy. The mechanism may be related to effects seen in ionomeric polymer metal composites (IPMCs), but with the response in plane rather than through the thickness of the film. Ultimately, these ionically conductive materials that can also be transparent and actuate, have the potential to be used in wearable devices.

Cluster-inspired Superionic Conductors

NASA Astrophysics Data System (ADS)

Fang, Hong; Jena, Puru

Superionic conductors with desirable properties hold the key to the development of next generation of rechargeable metal-ion batteries. In this study, we report a new family of superionic conductors composed by clusters based on the antiperovskite fast-ion conductors. The new lightweight conductor shows larger electrochemical stability window and favorable thermal and mechanical properties, while maintain a high Li+-ionconductivity at room temperature and a low activation energy. We reveal the conduction mechanism of the material by identifying the relation between the orientational symmetry of the cluster rotors and the potential surface felt by the lithium ion. We also find that the mixed phase of the new conductors show further enhanced conductivity.

Multiwire conductor having increased interwire resistance and good mechanical stability and method for making same

DOEpatents

Luhman, Thomas; Klamut, Carl

1984-02-14

An improved multiwire conductor of the type which is mechanically stabilized by a solder filler. A solder filled conductor is heated to a temperature sufficient to make the solder brittle, but below the melting point of the solder. While still hot, the conductor is flexed, causing the solder to separate from the wires comprising the conductor, thereby increasing the interwire resistance. In one embodiment the conductor may be heated to a temperature above the eutectic temperature of the solder so that a controlled amount of solder is removed. The subject invention is particularly suited for use with braided, ribbon-type, solder filled superconductors.

Multiwire conductor having increased interwire resistance and good mechanical stability and method for making same

DOEpatents

Luhman, T.; Klamut, C.

1982-03-15

An improved multiwire conductor of the type which is mechanically stabilized by a solder filler. A solder filled conductor is heated to a temperature sufficient to make the solder brittle, but below the melting point of the solder. While still hot, the conductor is flexed, causing the solder to separate from the wires comprising the conductor, thereby increasing the interwire resistance. In one embodiment the conductor may be heated to a temperature above the eutectic temperature of the solder so that a controlled amount of solder is removed. The subject invention is particularly suited for use with braided, ribbon-type, solder filled superconductors.

Hydrogel ionotronics

NASA Astrophysics Data System (ADS)

Yang, Canhui; Suo, Zhigang

2018-06-01

An ionotronic device functions by a hybrid circuit of mobile ions and mobile electrons. Hydrogels are stretchable, transparent, ionic conductors that can transmit electrical signals of high frequency over long distance, enabling ionotronic devices such as artificial muscles, skins and axons. Moreover, ionotronic luminescent devices, ionotronic liquid crystal devices, touchpads, triboelectric generators, artificial eels and gel-elastomer-oil devices can be designed based on hydrogels. In this Review, we discuss first-generation hydrogel ionotronic devices and the challenges associated with the mechanical properties and the chemistry of the materials. We examine how strong and stretchable adhesion between hydrophilic and hydrophobic polymer networks can be achieved, how water can be retained in hydrogels and how to design hydrogels that resist fatigue under cyclic loads. Finally, we highlight applications of hydrogel ionotronic devices and discuss the future of the field.

New Pyrazolium Salts as a Support for Ionic Liquid Crystals and Ionic Conductors.

PubMed

Pastor, María Jesús; Sánchez, Ignacio; Campo, José A; Schmidt, Rainer; Cano, Mercedes

2018-04-03

Ionic liquid crystals (ILCs) are a class of materials that combine the properties of liquid crystals (LCs) and ionic liquids (ILs). This type of materials is directed towards properties such as conductivity in ordered systems at different temperatures. In this work, we synthesize five new families of ILCs containing symmetrical and unsymmetrical substituted pyrazolium cations, with different alkyl long-chains, and anions such as Cl - , BF₄ - , ReO₄ - , p -CH₃-₆H₄SO₃ - (PTS) and CF₃SO₃ - (OTf). We study their thermal behavior by polarized light optical microscopy (POM) and differential scanning calorimetry (DSC). All of them, except those with OTf as counteranion, show thermotropic mesomorphism. The observations by POM reveal textures of lamellar mesophases. Those agree with the arrangement observed in the X-ray crystal structure of [H₂pz R(4),R(4) ][ReO₄]. The nature of the mesophases is also confirmed by variable temperature powder X-ray diffraction. On the other hand, the study of the dielectric properties at variable temperature in mesomorphic (Cl - and BF₄ - ) and non-mesomorphic (OTf) salts indicates that the supramolecular arrangement of the mesophase favors a greater ionic mobility and therefore ionic conductivity.

Synthesis and characterization of new ionic and mixed ionic/electronic conductors

NASA Astrophysics Data System (ADS)

Romito, Kevin Gregory

In a constantly growing and developing world, there is a great need to develop new forms of clean energy generation. Many solutions have been proposed to ameliorate these global concerns, which include fuel cell technology and new processes for reducing polluting chemicals in the atmosphere. These technologies are still in their infancy and require further development before becoming viable options. In the case of fuel cells, particularly solid oxide fuel cells, and CO 2 separation membranes, there is a need to develop ion conducting materials that are highly efficient, less costly to synthesize, and can perform strongly under many real-world conditions. The need for further developing these ion conductors is currently one of the most important final steps required to push these new technologies into the market. The research presented here focuses on the synthesis and characterization for several ion conductor systems intended for efficient energy conversion applications. Using a novel transient liquid phase sintering method, we demonstrate that it is possible to synthesize dense BaZr0.8Y 0.2O3-delta (BZY20) at 1300°C, a lower temperatures than previously reported, using barium gallate as a sintering flux. Focusing on a new family of oxide-ion conductors, Sr1-xK xSi1-yGeyO3-0.5x, gallium served as a replacement germanium in an effort to further increase the oxide-ion conductivity. Unfortunately, the replacement of Ge with Ga was found to decrease the overall oxide-ion conductivity and microstructural morphology. Through the addition of an Al2O3 layer to a porous silver matrix, we show that CO2 permeation flux density through a new MECC membrane can be enhanced as a result of improved retention of molten carbonate in the silver matrix. Pore size and distribution in the silver matrix were found to greatly depend on the concentration of Al2O 3 suspension.

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

Lü, Xujie; Howard, John W.; Chen, Aiping

We prepared antiperovskite Li 3OCl superionic conductor films via pulsed laser deposition using a composite target. A significantly enhanced ionic conductivity of 2.0 × 10 -4 S cm -1 at room temperature is achieved, and this value is more than two orders of magnitude higher than that of its bulk counterpart. Moreover, the applicability of Li 3OCl as a solid electrolyte for Li-ion batteries is demonstrated.

Electronic and Ionic Conductors from Ordered Microporous Materials

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

Dincă, Mircea

The proposed work aimed to establish metal-organic frameworks (MOFs) as new classes of high-surface area microporous electronic and ionic conductors. MOFs are crystalline materials with pore sizes ranging from 0.2 to ~ 2 nm (or larger for the latter) defined by inorganic or organic building blocks connected by rigid organic linkers. Myriad applications have been found or proposed for these materials, yet those that require electron transport or conductivity in combination with permanent porosity still lag behind because the vast majority of known frameworks are electrical insulators. Prior to our proposal and subsequent work, there were virtually no studies exploringmore » the possibility of electronic delocalization in these materials. Therefore, our primary goal was to understand and control, at a fundamental level, the electron and ion transport properties of this class of materials, with no specific application proposed, although myriad applications could be envisioned for high surface area conductors. Our goals directly addressed one of the DOE-identified Grand Challenges for Basic Energy Sciences: designing perfect atom- and energy-efficient syntheses of revolutionary new forms of matter with tailored properties. Indeed, the proposed work is entirely synthetic in nature; owing to the molecular nature of the building blocks in MOFs, there is the possibility of unprecedented control over the structure and properties of solid crystalline matter. The goals also tangentially addressed the Grand Challenge of controlling materials processes at the level of electrons: the scope of our program is to create new materials where charges (electrons and/or ions) move according to predefined pathways.« less

N7-(carboxymethyl)guanine-Lithium Crystalline Complex: A Bioinspired Solid Electrolyte

PubMed Central

Dutta, Dipak; Nagapradeep, N.; Zhu, Haijin; Forsyth, Maria; Verma, Sandeep; Bhattacharyya, Aninda J.

2016-01-01

Electrochemical device with components having direct significance to biological life processes is a potent futuristic strategy for the realization of all-round green and sustainable development. We present here synthesis design, structural analysis and ion transport of a novel solid organic electrolyte (G7Li), a compound reminiscent of ion channels, derived from regioisomeric N7-guanine-carboxylate conjugate and Li-ions. G7Li, with it’s in-built supply of Li+-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10−7 to 10−3 Ω−1 cm−1) as a function of moisture content. The ionic conductivity show a distinct reversible transition around 80–100 °C, from a dual Li+ and H+ (<100 °C) to a pure Li+ conductor (>100 °C). Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination. While as-synthesized G7Li has potential in humidity sensors, the anhydrous G7Li is attractive for rechargeable batteries. PMID:27091631

Design, development, fabrication and testing of high temperature Flat Conductor Cable (FCC)

NASA Technical Reports Server (NTRS)

Rigling, W. S.

1974-01-01

The results are presented of a development program for a flat, 25-conductor signal cable and a flat, 3-conductor power cable. Flat cables employ conductors made of strips or flattened round copper conductors insulated with polyimide films. It is shown that conductor thickness ranges from 0.003 to 0.010 inch, and begins to soften and loose mechanical strength at temperatures above 200 C.

Fabrication and modeling of stretchable conductors for traumatic brain injury research

NASA Astrophysics Data System (ADS)

Cao, Wenzhe

Stretchable electronics are an emergent class of electronics that can retain their electric functionality under large mechanical deformation, such as stretching, bending and compression. Like traditional electric circuits, stretchable electronics rely on electrical conductors, but in this specific instance the conductors must also be stretchable. This thesis research had three goals: (1) fabricate elastically stretchable conductors that retain their electrical conductance when stretched by tens of percent of strain; (2) understand the underlying stretching mechanism of gold conductors on polydimethylsiloxane (PDMS) substrates; (3) produce a special device---a stretchable microelectrode array, which contains a matrix of stretchable conductors that enables a new approach to studying traumatic brain injury. We first developed and optimized the micro-fabrication process to make elastically stretchable thin gold film conductors on PDMS substrates. The conductors can retain electrical conduction while being stretched reversibly to 140% uniaxially and 16% radially. We further developed a fabrication process to encapsulate the conductors with either a commercially available photopatternable silicone (PPS) or with PDMS. 100 microm by 100 microm vias were patterned in the encapsulation layer to expose electrical contacts. PPS encapsulated conductors can be stretched uniaxially to 80%, and the PDMS encapsulated conductor can be stretched to ˜15%, without losing electrical conduction. We also introduced acrylate-based shape memory polymers (SMPs) as a new type of substrate for stretchable conductors. Their stiffness can be tuned by varying the monomer composition or by changing the ambient temperature. Thin gold film conductors deposited on pre-strained SMPs remain conductive when first stretched and then relaxed to their pre-strain value. Moreover, an SMP can also serve as a stretchable carrier to make pre-strained conductors on an overlying PDMS membrane. The resistance of gold conductors made on pre-strained PDMS changes less during stretching than that made on non-pre-strained PDMS substrate. We built a model of the electrical resistance in function of strain. The model is based on the topography of the thin gold film on PDMS. This model is a first attempt at predicting electrical resistance of stretchable thin gold film conductors. Lastly, we fabricated stretchable microelectrode arrays (SMEAs). They were utilized at Columbia University to study traumatic brain injury (TBI). Tissues cultured on SMEA remained viable for 19 days, and the electrodes were able to both stimulate and record neural tissue activity before, during and after stretching. Therefore SMEAs are able to bring together mechanical injury, electrophysiological recording and pharmacological studies. The SMEAs could serve as in vitro platforms for high throughput therapeutic screening and discovery for traumatic injury. The ability to reproducibly fabricate stretchable conductors using micro-fabrication technology will facilitate adoption by industry. The ability to understand the stretching mechanism will enable us to design more robust material systems. The SMEA prototypes demonstrate that stretchable conductors are practical, and their mechanical compatibility with biological systems also makes them candidates for use in biomedical devices.

Resistive and Capacitive Memory Effects in Oxide Insulator/ Oxide Conductor Hetero-Structures

NASA Astrophysics Data System (ADS)

Meyer, Rene; Miao, Maosheng; Wu, Jian; Chevallier, Christophe

2013-03-01

We report resistive and capacitive memory effects observed in oxide insulator/ oxide conductor hetero-structures. Electronic transport properties of Pt/ZrO2/PCMO/Pt structures with ZrO2 thicknesses ranging from 20A to 40A are studied before and after applying short voltage pulses of positive and negative polarity for set and reset operation. As processed devices display a non-linear IV characteristic which we attribute to trap assisted tunneling through the ZrO2 tunnel oxide. Current scaling with electrode area and tunnel oxide thickness confirms uniform conduction. The set/reset operation cause an up/down shift of the IV characteristic indicating that the conduction mechanism of both states is still dominated by tunneling. A change in the resistance is associated with a capacitance change of the device. An exponential relation between program voltages and set times is found. A model based on electric field mediated non-linear transport of oxygen ions across the ZrO2/PCMO interface is proposed. The change in the tunnel current is explained by ionic charge transfer between tunnel oxide and conductive metal oxide changing both tunnel barrier height and PCMO conductivity. DFT techniques are employed to explain the conductivity change in the PCMO interfacial layer observed through capacitance measurements.

Sub-nA spatially resolved conductivity profiling of surface and interface defects in ceria films

DOE PAGES

Farrow, Tim; Yang, Nan; Doria, Sandra; ...

2015-03-17

Spatial variability of conductivity in ceria is explored using scanning probe microscopy with galvanostatic control. Ionically blocking electrodes are used to probe the conductivity under opposite polarities to reveal possible differences in the defect structure across a thin film of CeO2. Data suggest the existence of a large spatial inhomogeneity that could give rise to constant phase elements during standard electrochemical characterization, potentially affecting the overall conductivity of films on the macroscale. The approach discussed here can also be utilized for other mixed ionic electronic conductor systems including memristors and electroresistors, as well as physical systems such as ferroelectric tunnelingmore » barriers« less

On the correct choice of equivalent circuit for fitting bulk impedance data of ionic/electronic conductors

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

Hernández, Miguel A.; Masó, Nahum; West, Anthony R.

Bulk conductivity data of ionically and electronically conducting solid electrolytes and electronic ceramics invariably show a frequency dependence that cannot be modelled by a single-valued resistor. To model this, common practice is to add a constant phase element (CPE) in parallel with the bulk resistance. To fit experimental data on a wide variety of materials, however, it is also essential to include the limiting, high frequency permittivity of the material in the equivalent circuit. Failure to do so can lead to incorrect values for the sample resistance and CPE parameters and to an inappropriate circuit for materials that are electricallymore » heterogeneous.« less

Durable electrooptic devices comprising ionic liquids

DOEpatents

Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM

2006-10-10

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

First principle study of structural, elastic and electronic properties of APt3 (A=Mg, Sc, Y and Zr)

NASA Astrophysics Data System (ADS)

Benamer, A.; Roumili, A.; Medkour, Y.; Charifi, Z.

2018-02-01

We report results obtained from first principle calculations on APt3 compounds with A=Mg, Sc, Y and Zr. Our results of the lattice parameter a are in good agreement with experimental data, with deviations less than 0.8%. Single crystal elastic constants are calculated, then polycrystalline elastic moduli (bulk, shear and Young moduli, Poisson ration, anisotropy factor) are presented. Based on Debye model, Debye temperature ϴD is calculated from the sound velocities Vl, Vt and Vm. Band structure results show that the studied compounds are electrical conductors, the conduction mechanism is assured by Pt-d electrons. Different hybridisation states are observed between Pt-d and A-d orbitals. The study of the charge density distribution and the population analysis shows the coexistence of ionic, covalent and metallic bonds.

New Pyrazolium Salts as a Support for Ionic Liquid Crystals and Ionic Conductors

PubMed Central

Pastor, María Jesús; Sánchez, Ignacio; Schmidt, Rainer; Cano, Mercedes

2018-01-01

Ionic liquid crystals (ILCs) are a class of materials that combine the properties of liquid crystals (LCs) and ionic liquids (ILs). This type of materials is directed towards properties such as conductivity in ordered systems at different temperatures. In this work, we synthesize five new families of ILCs containing symmetrical and unsymmetrical substituted pyrazolium cations, with different alkyl long-chains, and anions such as Cl−, BF4−, ReO4−, p-CH3-6H4SO3− (PTS) and CF3SO3− (OTf). We study their thermal behavior by polarized light optical microscopy (POM) and differential scanning calorimetry (DSC). All of them, except those with OTf as counteranion, show thermotropic mesomorphism. The observations by POM reveal textures of lamellar mesophases. Those agree with the arrangement observed in the X-ray crystal structure of [H2pzR(4),R(4)][ReO4]. The nature of the mesophases is also confirmed by variable temperature powder X-ray diffraction. On the other hand, the study of the dielectric properties at variable temperature in mesomorphic (Cl− and BF4−) and non-mesomorphic (OTf) salts indicates that the supramolecular arrangement of the mesophase favors a greater ionic mobility and therefore ionic conductivity. PMID:29614030

High H⁻ ionic conductivity in barium hydride.

PubMed

Verbraeken, Maarten C; Cheung, Chaksum; Suard, Emmanuelle; Irvine, John T S

2015-01-01

With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H(-)) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm(-1) at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.

Size-Dependent Rupture Strain of Elastically Stretchable Metal Conductors

PubMed Central

Graudejus, O.; Jia, Z.; Li, T.; Wagner, S.

2012-01-01

Experiments show that the rupture strain of gold conductors on elastomers decreases as the conductors are made long and narrow. Rupture is caused by the irreversible coalescence of microcracks into one long crack. A mechanics model identifies a critical crack length ℓcr, above which the long crack propagates across the entire conductor width. ℓcr depends on the fracture toughness of the gold film and the width of the conductor. The model provides guidance for the design of highly stretchable conductors. PMID:22773917

Phase stability and processing of strontium and magnesium doped lanthanum gallate

NASA Astrophysics Data System (ADS)

Zheng, Feng

Fuel Cells are one of the most promising energy transformers with respect to ecological and environmental issues. Solid Oxide Fuel Cells (SOFC) are all solid-state devices. One of the challenges to improve a SOFC is to lower the operating temperature while maintaining or increasing its output voltage. Undoped LaGaO3 is an insulator, doping transforms it into an oxygen-ionic conductor. Sr and Mg doped LaGaO3 (LSGM) perovskite is a new oxygen-ionic conductor with higher conductivity than yttria-stabilized zirconia (YSZ). This material is a candidate for a wide variety of electrochemical devices. In order to realize this potential, the phase stability and processing of this material needs to be investigated in detail. In this study, a systematic investigation of the LSGM materials in terms of phase stability, phase transition, sintering, microstructure and electrical conductivity as functions of temperature, doping content and A/B cation ratio has been carried out. The generalized formula of the materials investigated is (La1--xSrx)A(Ga1--yMg y)BO3--delta. Optimized processing parameters have been obtained by investigating their impact on density change and microstructure. Consequently, a suitable compositional window of the LSGM perovskite has been identified for SOFC electrolyte applications. Based on detailed diffraction analysis, it is found that the undoped LaGaO3 takes on the orthorhombic (Pbnm) symmetry at room temperature. This structure changes to rhombohedral (R3c) at 147 +/- 2°C or changes to monoclinic (I2/a) when the doping level increases from 0.1 to 0.2 moles. We have optimized the compositional window to make the single perovskite phase with high oxygen ionic conductivity (x = 0.10 to 0.20 with A/B ratio between 0.98 to 1.02). The best processing condition, starting from glycine nitrate process (GNP) combustion synthesized ultra-fine LSGM powder, is sintering in air at 1500°C for 2 hours. The doped material has higher oxygen ionic conductivity than YSZ at all temperatures. In addition, based on the structure and phase relations, a high temperature phase diagram for this system has been proposed. Finally, a model has been proposed to account for the high ionic conductivity of this material and to explain the effect of the doping content and the stoichiometry on the ionic conductivity. (Abstract shortened by UMI.)

Microstructural Control and Characterization of Bi2V0.9Cu0.1O5.35 (BICUVOX) Ceramics

NASA Astrophysics Data System (ADS)

Razmyar, Soheil

2011-12-01

The widespread commercialization of solid-oxide fuel cells (SOFCs) and solid-oxide electrolyte cells (SOECs) is primarily limited by material degradation issues related to the required high temperature operation (>800°C). Applications of stabilized zirconia based electrolytes, which are the most commonly used oxide ion conductors, have been limited to this high temperature regime due to its low oxygen ion conductivity below 800°C. Solid electrolytes made of the BIMEVOX compositional family of materials (Bi2MexV 1-xO5.5-delta where Me=Cu, Co, Mg, Ni, Fe...) exhibit high oxide ionic conductivity similar to YSZ at a low temperature (300--600°C). Among these materials copper-substituted bismuth vanadate (Bi2V0.9Cu0.1O5.35, BICUVOX), was reported to have the highest ionic conductivity at 400°C (0.02 S/cm). It's one of the most important drawbacks of using BICUVOX, as a SOFC electrolyte is the low mechanical strength, which makes it unusable for most electrolyte supported applications. This research aims at improving mechanical strength by careful control of synthesis processing and sintering processes, thus making BICUVOX a viable material option for intermediate temperature SOFC. A co-precipitation method was used to synthesize submicron BICUVOX powder. The powder was utilized to fabricate a thin (< 250 microm) BICUVOX electrolyte membrane, with 2.5 cm2 active area and high mechanical strength. The fabricated BICUVOX membranes were densified to 97% theoretical density at lower sintering temperature and shorter time (675°C/1 h), and shows fine grain size (<1.5microm) and high mechanical strength (159 MPa).

Amino acid anions in organic ionic compounds. An ab initio study of selected ion pairs.

PubMed

Benedetto, A; Bodo, E; Gontrani, L; Ballone, P; Caminiti, R

2014-03-06

The combination of amino acids in their deprotonated and thus anionic form with a choline cation gives origin to a new and potentially important class of organic ionic compounds. A series of such neutral ion pairs has been investigated by first principle methods. The results reveal intriguing structural motives as well as regular patterns in the charge distribution and predict a number of vibrational and optical properties that could guide the experimental investigation of these compounds. The replacement of choline with its phosphocholine analogue causes the spontaneous reciprocal neutralization of cations and anions, taking place through the transfer of a proton between the two ions. Systems of this kind, therefore, provide a wide and easily accessible playground to probe the ionic/polar transition in organic systems, while the easy transfer of H(+) among neutral and ionic species points to their potential application as proton conductors. The analysis of the ab initio data highlights similarities as well as discrepancies from the rigid-ions force-field picture and suggests directions for the improvement of empirical models.

The Leaky Dielectric Model as a Weak Electrolyte Limit of an Electrodiffusion Model

NASA Astrophysics Data System (ADS)

Mori, Yoichiro; Young, Yuan-Nan

2017-11-01

The Taylor-Melcher (TM) model is the standard model for the electrohydrodynamics of poorly conducting leaky dielectric fluids under an electric field. The TM model treats the fluid as an ohmic conductor, without modeling ion dynamics. On the other hand, electrodiffusion models, which have been successful in describing electokinetic phenomena, incorporates ionic concentration dynamics. Mathematical reconciliation between electrodiffusion and the TM models has been a major issue for electrohydrodynamic theory. Here, we derive the TM model from an electrodiffusion model where we explicitly model the electrochemistry of ion dissociation. We introduce salt dissociation reaction in the bulk and take the limit of weak salt dissociation (corresponding to poor conductors in the TM model.) Assuming small Debye length we derive the TM model with or without the surface charge advection term depending upon the scaling of relevant dimensionless parameters. Our analysis also gives a description of the ionic concentration distribution within the Debye layer, which hints at possible scenarios for electrohydrodynamic singularity formation. In our analysis we also allow for a jump in voltage across the liquid interface which causes a drifting velocity for a liquid drop under an electric field. YM is partially supported by NSF-DMS-1516978 and NSF-DMS-1620316. YNY is partially supported by NSF-DMS-1412789 and NSF-DMS-1614863.

Thermal management of advanced fuel cell power systems

NASA Technical Reports Server (NTRS)

Vanderborgh, N. E.; Hedstrom, J.; Huff, J.

1990-01-01

It is shown that fuel cell devices are particularly attractive for the high-efficiency, high-reliability space hardware necessary to support upcoming space missions. These low-temperature hydrogen-oxygen systems necessarily operate with two-phase water. In either PEMFCs (proton exchange membrane fuel cells) or AFCs (alkaline fuel cells), engineering design must be critically focused on both stack temperature control and on the relative humidity control necessary to sustain appropriate conductivity within the ionic conductor. Water must also be removed promptly from the hardware. Present designs for AFC space hardware accomplish thermal management through two coupled cooling loops, both driven by a heat transfer fluid, and involve a recirculation fan to remove water and heat from the stack. There appears to be a certain advantage in using product water for these purposes within PEM hardware, because in that case a single fluid can serve both to control stack temperature, operating simultaneously as a heat transfer medium and through evaporation, and to provide the gas-phase moisture levels necessary to set the ionic conductor at appropriate performance levels. Moreover, the humidification cooling process automatically follows current loads. This design may remove the necessity for recirculation gas fans, thus demonstrating the long-term reliability essential for future space power hardware.

Determination of electrical properties of degraded mixed ionic conductors: Impedance studies with applied dc voltage

NASA Astrophysics Data System (ADS)

Bayer, T. J. M.; Carter, J. J.; Wang, Jian-Jun; Klein, Andreas; Chen, Long-Qing; Randall, C. A.

2017-12-01

Under electrical bias, mixed ionic conductors such as SrTiO3 are characterized by oxygen vacancy migration which leads to resistance degradation. The defect chemistry to describe the relationship between conductivity and oxygen vacancies is usually obtained by high temperature conductivity data or quenching experiments. These techniques can investigate the equilibrated state only. Here, we introduce a new approach using in-situ impedance studies with applied dc voltage to analyze the temperature dependent electrical properties of degraded SrTiO3 single crystals. This procedure is most beneficial since it includes electric field driven effects. The benefits of the approach are highlighted by comparing acceptor doped and undoped SrTiO3. This approach allows the determination of the temperature activation of both anodic and cathodic conductivity of Fe-doped SrTiO3 in the degraded state. The anodic activation energy matches well with the published results, while the activation energy of the degraded cathode region reported here is not in agreement with earlier assumptions. The specific discrepancies of the experimental data and the published defect chemistry are discussed, and a defect chemistry model that includes the strong temperature dependence of the electron conductivity in the cathode region is proposed.

Correlation of anisotropy and directional conduction in β-Li 3PS 4 fast Li + conductor

DOE PAGES

Chen, Yan; Cai, Lu; Liu, Zengcai; ...

2015-07-06

Our letter reports the correlation of anisotropy and directional conduction in the fast Li + conductor β-Li 3PS 4, one of the low-symmetry crystalline electrolyte candidates. The material has both high conductivity and good stability that serves well for the large-scale energy storage applications of all-solid-state lithium ion batteries. The anisotropic physical properties, demonstrated here by the thermal expansion coefficients, are crucial for compatibility in the solid-state system and battery performance. Neutron and X-ray powder diffraction measurements were done to determine the crystal structure and thermal stability. Moreover, the crystallographic b-axis was revealed as a fast expansion direction, while negligiblemore » thermal expansion was observed along the a-axis around the battery operating temperatures. The anisotropic behavior has its structural origin from the Li + conduction channels with incomplete Li occupancy and a flexible connection of LiS 4 and PS 4 tetrahedra within the framework. This indicates a strong correlation in the direction of the ionic transport in the low-symmetry Li + conductor.« less

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

NASA Astrophysics Data System (ADS)

Lee, Shinbuhm; MacManus-Driscoll, Judith L.

2017-04-01

This review provides the design principles to develop new nanoionic applications using vertically aligned nanostructured (VAN) thin films, incorporating two phases which self-assemble in one film. Tunable nanoionics has attracted great attention for energy and device applications, such as ion batteries, solid oxide fuel cells, catalysts, memories, and neuromorphic devices. Among many proposed device architectures, VAN films have strong potential for nanoionic applications since they show enhanced ionic conductivity and tunability. Here, we will review the recent progress on state-of-the-art nanoionic applications, which have been realized by using VAN films. In many VAN systems made by the inclusion of an oxygen ionic insulator, it is found that ions flow through the vertical heterointerfaces. The observation is consistent with structural incompatibility at the vertical heteroepitaxial interfaces resulting in oxygen deficiency in one of the phases and hence to oxygen ion conducting pathways. In other VAN systems where one of the phases is an ionic conductor, ions flow much faster within the ionic conducting phase than within the corresponding plain film. The improved ionic conduction coincides with much improved crystallinity in the ionically conducting nanocolumnar phase, induced by use of the VAN structure. Furthermore, for both cases Joule heating effects induced by localized ionic current flow also play a role for enhanced ionic conductivity. Nanocolumn stoichiometry and strain are other important parameters for tuning ionic conductivity in VAN films. Finally, double-layered VAN film architectures are discussed from the perspective of stabilizing VAN structures which would be less stable and hence less perfect when grown on standard substrates.

Crystal Chemistry and Conductivity Studies in the System La 0.5+ x+ yLi 0.5-3 xTi 1-3 yCr 3 yO 3

NASA Astrophysics Data System (ADS)

Martínez-Sarrión, M. L.; Mestres, L.; Morales, M.; Herraiz, M.

2000-12-01

The stoichiometry polymorphism and electrical behavior of solid solutions La0.5+x+yLi0.5-3xTi1-3yCr3yO3 with perovskite-type structure were studied. Data are given in the form of a solid solutions triangle, phase diagrams, XRD patterns for the three polymorphs, A, β, and C, composition dependence of their lattice parameters, and ionic and electronic conductivity plots. Microstructure and composition were studied by SEM/EDS and electron probe microanalysis. These compounds are mixed conductors. Ionic conductivity decreased when the amount of lithium diminished and electronic conductivity increased with chromium content.

Resistive coating for current conductors in cryogenic applications

DOEpatents

Hirayama, Chikara; Wagner, George R.

1982-05-18

This invention relates to a resistive or semiconducting coating for use on current conductors in cryogenic applications. This includes copper-clad superconductor wire, copper wire used for stabilizing superconductor magnets, and for hyperconductors. The coating is a film of cuprous sulfide (Cu.sub.2 S) that has been found not to degrade the properties of the conductors. It is very adherent to the respective conductors and satisfies the mechanical, thermal and electrical requirements of coatings for the conductors.

High conductivity composite metal

DOEpatents

Zhou, Ruoyi; Smith, James L.; Embury, John David

1998-01-01

Electrical conductors and methods of producing them, where the conductors possess both high strength and high conductivity. Conductors are comprised of carbon steel and a material chosen from a group consisting of copper, nickel, silver, and gold. Diffusion barriers are placed between these two materials. The components of a conductor are assembled and then the assembly is subjected to heat treating and mechanical deformation steps.

Role of semiconductivity and ion transport in the electrical conduction of melanin

PubMed Central

Mostert, Albertus B.; Powell, Benjamin J.; Pratt, Francis L.; Hanson, Graeme R.; Sarna, Tadeusz; Gentle, Ian R.; Meredith, Paul

2012-01-01

Melanins are pigmentary macromolecules found throughout the biosphere that, in the 1970s, were discovered to conduct electricity and display bistable switching. Since then, it has been widely believed that melanins are naturally occurring amorphous organic semiconductors. Here, we report electrical conductivity, muon spin relaxation, and electron paramagnetic resonance measurements of melanin as the environmental humidity is varied. We show that hydration of melanin shifts the comproportionation equilibrium so as to dope electrons and protons into the system. This equilibrium defines the relative proportions of hydroxyquinone, semiquinone, and quinone species in the macromolecule. As such, the mechanism explains why melanin at neutral pH only conducts when “wet” and suggests that both carriers play a role in the conductivity. Understanding that melanin is an electronic-ionic hybrid conductor rather than an amorphous organic semiconductor opens exciting possibilities for bioelectronic applications such as ion-to-electron transduction given its biocompatibility. PMID:22615355

Magneto-ionic effect in CoFeB thin films with in-plane and perpendicular-to-plane magnetic anisotropy

NASA Astrophysics Data System (ADS)

Baldrati, L.; Tan, A. J.; Mann, M.; Bertacco, R.; Beach, G. S. D.

2017-01-01

The magneto-ionic effect is a promising method to control the magnetic properties electrically. Charged mobile oxygen ions can easily be driven by an electric field to modify the magnetic anisotropy of a ferromagnetic layer in contact with an ionic conductor in a solid-state device. In this paper, we report on the room temperature magneto-ionic modulation of the magnetic anisotropy of ultrathin CoFeB films in contact with a GdOx layer, as probed by polar micro-Magneto Optical Kerr Effect during the application of a voltage across patterned capacitors. Both Pt/CoFeB/GdOx films with perpendicular magnetic anisotropy and Ta/CoFeB/GdOx films with uniaxial in-plane magnetic anisotropy in the as-grown state exhibit a sizable dependence of the magnetic anisotropy on the voltage (amplitude, polarity, and time) applied across the oxide. In Pt/CoFeB/GdOx multilayers, it is possible to reorient the magnetic anisotropy from perpendicular-to-plane to in-plane, with a variation of the magnetic anisotropy energy greater than 0.2 mJ m-2. As for Ta/CoFeB/GdOx multilayers, magneto-ionic effects still lead to a sizable variation of the in-plane magnetic anisotropy, but the anisotropy axis remains in-plane.

Highly Stretchable Conductors Based on Expanded Graphite Macroconfined in Tubular Rubber.

PubMed

Luo, Wei; Wu, Tongfei; Chen, Biqiong; Liang, Mei; Zou, Huawei

2017-12-13

Highly stretchable and durable conductors are significant to the development of wearable devices, robots, human-machine interfaces, and other artificial intelligence products. Although many respectable methods have been reported, it is still a challenge to fabricate stretchable conductors with a large elastic limit, high conductivity, and excellent reliability in rapid, effective, and economic ways. Herein, a facile method is offered to fabricate high-performance stretchable tubular conductors (TCs) based on a macroconfined structure of expanded graphite (EG) in rubber tubing by simply physical packing. The maximum original electrical conductivity of TCs reached a high value of 160.6 S/cm. Meanwhile, TCs showed more insensitive response of conductivity to increasing tensile strain compared to the TCs encapsulated with liquid metal or ionic liquid. The conductivity and effective stretchability of TCs can be adjusted by varying the packing density of EG. A low gauge factor below 3 was reached even under 400% stretching for TCs with a packing density of 1.233 g/cm 3 . The excellent resilience and good stability of conductivity of TCs during dynamic stretching-releasing cycles are attributed to the stable and rapid reconstruction of the percolation network of EG particles. The combination of high conductivity, tunable stretchability, and good reliability renders potential applications to TCs, such as highly stretchable interconnects or strain sensors, in human motion detection.

Strongly coupled Sm0.2Ce0.8O2-Na2CO3 nanocomposite for low temperature solid oxide fuel cells: One-step synthesis and super interfacial proton conduction

NASA Astrophysics Data System (ADS)

Zhang, Guanghong; Li, Wenjian; Huang, Wen; Cao, Zhiqun; Shao, Kang; Li, Fengjiao; Tang, Chaoyun; Li, Cuihua; He, Chuanxin; Zhang, Qianling; Fan, Liangdong

2018-05-01

Highly conductive ceria-carbonate composite represents one type of most promising electrolyte materials for low temperature solid oxide fuel cells (SOFCs). Composites with large oxide-carbonate interface and homogeneous element/phase distribution are desirable to further enhance electrical properties and to study the ionic conduction mechanism. In this work, we report the successful synthesis of element/phase well-distributed, interfacial strongly coupled Sm0.2Ce0.8O2-Na2CO3 (NSDC) nanocomposite with different residual carbonate contents by an in-situ one-pot one-step citric acid-nitrate combustion method. Interestingly, NSDC shows distinct properties over those prepared by conventional methods and improved ionic conductivity. In particular, NSDC9010 nanocomposite displays a proton conductivity of 0.044 S cm-1 at 650 °C, which is 3-5 times higher than the oxide proton conductors. Electrolyte supported SOFCs based on the resultant nanocomposite electrolyte, NSDC9010, give the best power output of 281.5 mW cm-2 at 600 °C with LiNiO2 symmetric electro-catalysts. The excellent ionic conductivity and fuel cell performance are correlated with the unique core-shell structure, good phase distribution and large interfacial area induced by the one-step fabrication method, the strong coupling between oxide and carbonate as verified by the differential thermal and Raman spectroscopy characterization results and the optimal interfacial carbonate layer thickness by intentionally adjusting of carbonate contents.

High conductivity composite metal

DOEpatents

Zhou, R.; Smith, J.L.; Embury, J.D.

1998-01-06

Electrical conductors and methods of producing them are disclosed, where the conductors possess both high strength and high conductivity. Conductors are comprised of carbon steel and a material chosen from a group consisting of copper, nickel, silver, and gold. Diffusion barriers are placed between these two materials. The components of a conductor are assembled and then the assembly is subjected to heat treating and mechanical deformation steps. 10 figs.

Complex hydrides as room-temperature solid electrolytes for rechargeable batteries

NASA Astrophysics Data System (ADS)

de Jongh, P. E.; Blanchard, D.; Matsuo, M.; Udovic, T. J.; Orimo, S.

2016-03-01

A central goal in current battery research is to increase the safety and energy density of Li-ion batteries. Electrolytes nowadays typically consist of lithium salts dissolved in organic solvents. Solid electrolytes could facilitate safer batteries with higher capacities, as they are compatible with Li-metal anodes, prevent Li dendrite formation, and eliminate risks associated with flammable organic solvents. Less than 10 years ago, LiBH4 was proposed as a solid-state electrolyte. It showed a high ionic conductivity, but only at elevated temperatures. Since then a range of other complex metal hydrides has been reported to show similar characteristics. Strategies have been developed to extend the high ionic conductivity of LiBH4 down to room temperature by partial anion substitution or nanoconfinement. The present paper reviews the recent developments in complex metal hydrides as solid electrolytes, discussing in detail LiBH4, strategies towards for fast room-temperature ionic conductors, alternative compounds, and first explorations of implementation of these electrolytes in all-solid-state batteries.

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

Wang, Hui; Chen, Yan; Hood, Zachary D.

All-solid-state sodium batteries, using abundant sodium resources and solid electrolyte, hold much promise for safe, low cost, large-scale energy storage. To realize the practical applications of all solid Na-ion batteries at ambient temperature, the solid electrolytes are required to have high ionic conductivity, chemical stability, and ideally, easy preparation. Ceramic electrolytes show higher ionic conductivity than polymers, but they often require extremely stringent synthesis conditions, either high sintering temperature above 1000 C or long-time, low-energy ball milling. Herein, we report a new synthesis route for Na 3SbS 4, a novel Na superionic conductor that needs much lower processing temperature belowmore » 200 C and easy operation. This new solid electrolyte exhibits a remarkable ionic conductivity of 1.05 mS cm -1 at 25 °C and is chemically stable under ambient atmosphere. In conclusion, this synthesis process provides unique insight into the current state-of-the-art solid electrolyte preparation and opens new possibilities for the design of similar materials.« less

The mechanism and realization of a band-agile coaxial relativistic backward-wave oscillator

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

Ge, Xingjun; Zhang, Jun; Zhong, Huihuang

2014-11-03

The mechanism and realization of a band-agile coaxial relativistic backward-wave oscillator (RBWO) are presented. The operation frequency tuning can be easily achieved by merely altering the inner-conductor length. The key effects of the inner-conductor length contributing to the mechanical frequency tunability are investigated theoretically and experimentally. There is a specific inner-conductor length where the operation frequency can jump from one mode to another mode, which belongs to a different operation band. In addition, the operation frequency is tunable within each operation band. During simulation, the L-band microwave with a frequency of 1.61 GHz is radiated when the inner-conductor length ismore » 39 cm. Meanwhile, the S-band microwave with a frequency of 2.32 GHz is radiated when the inner-conductor length is 5 cm. The frequency adjustment bandwidths of L-band and S-band are about 8.5% and 2%, respectively. Moreover, the online mechanical tunability process is described in detail. In the initial experiment, the generated microwave frequencies remain approximately 1.59 GHz and 2.35 GHz when the inner-conductor lengths are 39 cm and 5 cm. In brief, this technical route of the band-agile coaxial RBWO is feasible and provides a guide to design other types of band-agile high power microwaves sources.« less

Bitter-type magnet plate design with compound conductor of ultrahigh mechanical strength

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

Haubenberger, W.D.

1981-01-01

A Bitter-type magnet plate design based on a compound conductor of ultrahigh mechanical strength is described. An explosion-bonded and cold-worked copper-austenite compound is jointed by a special procedure with a soft compound sheet.

Multiwire conductor having greatly increased interwire resistance and method for making same

DOEpatents

Luhman, Thomas; Suenaga, Masaki

1984-01-17

An improved multiwire conductor of the type which is mechanically stabilized by a tin based solder filler. A solder filled conductor is heated to a temperature above its melting point for a period long enough to allow a substantial amount of copper to be dissolved from the wires comprising the conductor. The copper forms the brittle intermetallic compound Cu.sub.5 Sn.sub.6 with tin in the solder. After cooling the conductor is flexed causing a random cracking of the solder, and thereby increasing the interwire resistance of the conductor. The subject invention is particularly adapted for use with braided, ribbon-type solder filled superconductors.

Instant tough bonding of hydrogels for soft machines and electronics

PubMed Central

Wirthl, Daniela; Pichler, Robert; Drack, Michael; Kettlguber, Gerald; Moser, Richard; Gerstmayr, Robert; Hartmann, Florian; Bradt, Elke; Kaltseis, Rainer; Siket, Christian M.; Schausberger, Stefan E.; Hild, Sabine; Bauer, Siegfried; Kaltenbrunner, Martin

2017-01-01

Introducing methods for instant tough bonding between hydrogels and antagonistic materials—from soft to hard—allows us to demonstrate elastic yet tough biomimetic devices and machines with a high level of complexity. Tough hydrogels strongly attach, within seconds, to plastics, elastomers, leather, bone, and metals, reaching unprecedented interfacial toughness exceeding 2000 J/m2. Healing of severed ionic hydrogel conductors becomes feasible and restores function instantly. Soft, transparent multilayered hybrids of elastomers and ionic hydrogels endure biaxial strain with more than 2000% increase in area, facilitating soft transducers, generators, and adaptive lenses. We demonstrate soft electronic devices, from stretchable batteries, self-powered compliant circuits, and autonomous electronic skin for triggered drug delivery. Our approach is applicable in rapid prototyping and in delicate environments inaccessible for extended curing and cross-linking. PMID:28691092

Novel Proton Conducting Solid Bio-polymer Electrolytes Based on Carboxymethyl Cellulose Doped with Oleic Acid and Plasticized with Glycerol

NASA Astrophysics Data System (ADS)

Chai, M. N.; Isa, M. I. N.

2016-06-01

The plasticized solid bio-polymer electrolytes (SBEs) system has been formed by introducing glycerol (Gly) as the plasticizer into the carboxymethyl cellulose (CMC) doped with oleic acid (OA) via solution casting techniques. The ionic conductivity of the plasticized SBEs has been studied using Electrical Impedance Spectroscopy. The highest conductivity achieved is 1.64 × 10-4 S cm-1 for system containing 40 wt. % of glycerol. FTIR deconvolution technique had shown that the conductivity of CMC-OA-Gly SBEs is primarily influenced by the number density of mobile ions. Transference number measurement has shown that the cation diffusion coefficient and ionic mobility is higher than anion which proved the plasticized polymer system is a proton conductor.

Instant tough bonding of hydrogels for soft machines and electronics.

PubMed

Wirthl, Daniela; Pichler, Robert; Drack, Michael; Kettlguber, Gerald; Moser, Richard; Gerstmayr, Robert; Hartmann, Florian; Bradt, Elke; Kaltseis, Rainer; Siket, Christian M; Schausberger, Stefan E; Hild, Sabine; Bauer, Siegfried; Kaltenbrunner, Martin

2017-06-01

Introducing methods for instant tough bonding between hydrogels and antagonistic materials-from soft to hard-allows us to demonstrate elastic yet tough biomimetic devices and machines with a high level of complexity. Tough hydrogels strongly attach, within seconds, to plastics, elastomers, leather, bone, and metals, reaching unprecedented interfacial toughness exceeding 2000 J/m 2 . Healing of severed ionic hydrogel conductors becomes feasible and restores function instantly. Soft, transparent multilayered hybrids of elastomers and ionic hydrogels endure biaxial strain with more than 2000% increase in area, facilitating soft transducers, generators, and adaptive lenses. We demonstrate soft electronic devices, from stretchable batteries, self-powered compliant circuits, and autonomous electronic skin for triggered drug delivery. Our approach is applicable in rapid prototyping and in delicate environments inaccessible for extended curing and cross-linking.

Glass transition dynamics and conductivity scaling in ionic deep eutectic solvents: The case of (acetamide + lithium nitrate/sodium thiocyanate) melts.

PubMed

Tripathy, Satya N; Wojnarowska, Zaneta; Knapik, Justyna; Shirota, Hideaki; Biswas, Ranjit; Paluch, Marian

2015-05-14

A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10(-1)-10(6) Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transition temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai's coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors.

Synthesis, structure, and ionic conductivity of solid solution, Li10+δM1+δP2-δS12 (M = Si, Sn).

PubMed

Hori, Satoshi; Suzuki, Kota; Hirayama, Masaaki; Kato, Yuki; Saito, Toshiya; Yonemura, Masao; Kanno, Ryoji

2014-01-01

Solid solutions of the silicon and tin analogous phases of the superionic conductor Li(10)MP(2)S(12) (M = Si, Sn) were synthesized by a conventional solid-state reaction in an evacuated silica tube at 823 K. The ranges of the solid solutions were determined to be 0.20 < δ < 0.43 and -0.25 < δ < -0.01 in Li(10+δ)M(1+δ)P(2-δ)S(12) (0.525 ≤k≤ 0.60 and 0.67 ≤k≤ 0.75 in Li(4-k)M(1-k)PkS(4)) for the Si and Sn systems, respectively. The ionic conductivity of these systems varied as a function of the changing M ions: the Si and Sn systems showed lower conductivity than the Ge system, Li(10+δ)Ge(1+δ)P(2-δ)S(12). The conductivity change for different elements might be due to the lattice size and lithium content affecting the ionic conduction. The relationship between ionic conduction, structure, and lithium concentration is discussed based on the structural and electrochemical information for the silicon, germanium, and tin systems.

Computational and Experimental Investigations of Na-Ion Conduction in Cubic Na 3PSe 4

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

Bo, Shou -Hang; Wang, Yan; Kim, Jae Chul

All-solid-state Na-ion batteries that operate at or close to room temperature are a promising next-generation battery technology with enhanced safety and reduced manufacturing cost. An indispensable component of this technology is the solid-state electrolyte that allows rapid shuttling of the mobile cation (i.e., Na +) between the cathode and anode. However, there are very few fast Na-ion conductors with ionic conductivity approaching that of the liquid counterparts (i.e., 1 mS cm –1). In this work, we present the synthesis and characterization of a fast Na-ion conductor, cubic Na 3PSe 4. This material possesses a room-temperature ionic conductivity exceeding 0.1 mSmore » cm –1 and does not require high-temperature sintering to minimize grain boundary resistance, making it a promising solid-state electrolyte candidate for all-solid-state Na-ion battery applications. On the basis of density functional theory, nudged elastic band, and molecular dynamics investigations, we demonstrate that the framework of cubic Na 3PSe 4 only permits rapid Na + diffusion with the presence of defects, and that the formation of the Na vacancy (charge-balanced by slight Se 2– oxidation) is more energetically favorable among the various defects considered. This finding provides important guidelines to further improve Na-ion conductivity in this class of materials.« less

Computational and Experimental Investigations of Na-Ion Conduction in Cubic Na 3PSe 4

DOE PAGES

Bo, Shou -Hang; Wang, Yan; Kim, Jae Chul; ...

2015-11-17

All-solid-state Na-ion batteries that operate at or close to room temperature are a promising next-generation battery technology with enhanced safety and reduced manufacturing cost. An indispensable component of this technology is the solid-state electrolyte that allows rapid shuttling of the mobile cation (i.e., Na +) between the cathode and anode. However, there are very few fast Na-ion conductors with ionic conductivity approaching that of the liquid counterparts (i.e., 1 mS cm –1). In this work, we present the synthesis and characterization of a fast Na-ion conductor, cubic Na 3PSe 4. This material possesses a room-temperature ionic conductivity exceeding 0.1 mSmore » cm –1 and does not require high-temperature sintering to minimize grain boundary resistance, making it a promising solid-state electrolyte candidate for all-solid-state Na-ion battery applications. On the basis of density functional theory, nudged elastic band, and molecular dynamics investigations, we demonstrate that the framework of cubic Na 3PSe 4 only permits rapid Na + diffusion with the presence of defects, and that the formation of the Na vacancy (charge-balanced by slight Se 2– oxidation) is more energetically favorable among the various defects considered. This finding provides important guidelines to further improve Na-ion conductivity in this class of materials.« less

Hybrid electrolytes for lithium metal batteries

NASA Astrophysics Data System (ADS)

Keller, Marlou; Varzi, Alberto; Passerini, Stefano

2018-07-01

This perspective article discusses the most recent developments in the field of hybrid electrolytes, here referred to electrolytes composed of two, well-defined ion-conducting phases, for high energy density lithium metal batteries. The two phases can be both solid, as e.g., two inorganic conductors or one inorganic and one polymer conductor, or, differently, one liquid and one inorganic conductor. In this latter case, they are referred as quasi-solid hybrid electrolytes. Techniques for the appropriate characterization of hybrid electrolytes are discussed emphasizing the importance of ionic conduction and interfacial properties. On this view, multilayer systems are also discussed in more detail. Investigations on Lewis acid-base interactions, activation energies for lithium-ion transfer between the phases, and the formation of an interphase between the components are reviewed and analyzed. The application of different hybrid electrolytes in lithium metal cells with various cathode compositions is also discussed. Fabrication methods for the feasibility of large-scale applications are briefly analyzed and different cell designs and configurations, which are most suitable for the integration of hybrid electrolytes, are determined. Finally, the specific energy of cells containing different hybrid electrolytes is estimated to predict possible enhancement in energy with respect to the current lithium-ion battery technology.

High current superconductors for tokamak toroidal field coils

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

Fietz, W.A.

1976-01-01

Conductors rated at 10,000 A for 8 T and 4.2 K are being purchased for the first large coil segment tests at ORNL. Requirements for these conductors, in addition to the high current rating, are low pulse losses, cryostatic stability, and acceptable mechanical properties. The conductors are required to have losses less than 0.4 W/m under pulsed fields of 0.5 T with a rise time of 1 sec in an ambient 8-T field. Methods of calculating these losses and techniques for verifying the performance by direct measurement are discussed. Conductors stabilized by two different cooling methods, pool boiling and forcedmore » helium flow, have been proposed. Analysis of these conductors is presented and a proposed definition and test of stability is discussed. Mechanical property requirements, tensile and compressive, are defined and test methods are discussed.« less

Na Diffusion in Quasi One-Dimensional Ion Conductor NaMn2O4 Observed by μ+SR

NASA Astrophysics Data System (ADS)

Umegaki, Izumi; Nozaki, Hiroshi; Harada, Masashi; Månsson, Martin; Sakurai, Hiroya; Kawasaki, Ikuto; Watanabe, Isao; Sugiyama, Jun

A quasi one-dimensional (1D) compound, NaMn2O4, in which Mn2O4 zigzag chains form a 1D channel along the b-axis and Na ions locate at the center of the channel, is thought to be a good Na ionic conductor. In order to study Na-ion diffusion, we have measured μ+SR spectra using a powder sample in the temperature range between 100 and 500 K. A diffusive behavior was clearly observed above 325 K. Assuming a thermal activate process for jump diffusion of Na-ion between two nearest neighboring sites, a self diffusion coefficient of Na ion (DNa) and its activation energy (Ea) were estimated as DNa = (3.1 ± 0.2) × 10 - 11 cm2/s at 350 K and Ea = 180(9) meV.

Multiwire conductor having greatly increased interwire resistance and method for making same

DOEpatents

Luhman, T.; Suenaga, M.

1982-03-15

An improved multiwire conductor of the type which is mechanically stabilized by a tin based solder filler is described. A solder filled conductor is heated to a temperature above its melting point for a period long enough to allow a substantial amount of copper to be dissolved from the wires comprising the conductor. The copper forms the brittle intermetallic compound Cu/sub 5/Sn/sub 6/ with tin in the solder. After cooling the conductor is flexed causing a random cracking of the solder, and thereby increasing the interwire resistance of the conductor. The subject invention is particularly adapted for use with braided, ribbon-type solder filled superconductors.

Application of the solubility parameter concept to the design of chemiresistor arrays

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

Hughes, R.C.; Yelton, W.G.; Ricco, A.J.

1998-04-01

Arrays of unheated chemically sensitive resistors (chemiresistors) can serve as extremely small, low power consumption sensors with simple read out electronics. Most work has focused on the exotic polymeric organic metals, but here the authors report new results on carbon loaded polymer composites, as well as polymeric ionic conductors. They use the solubility parameter concept to understand and categorize the chemiresistor responses and, in particular, they compare chemiresistors fabricated from polyisobutylene (PIB) to results from PIB coated acoustic wave sensors.

Phase equilibria and crystal chemistry of rubidium niobates and rubidium tantalates

NASA Technical Reports Server (NTRS)

Minor, D. B.; Roth, R. S.; Parker, H. S.; Brower, W. S.

1977-01-01

The phase equilibria relations and crystal chemistry of portions of the Rb2O-Nb2O5 and Rb2O-Ta2O5 systems were investigated for structures potentially useful as ionic conductors. A hexagonal tungsten bronze-type (HTB) structure was found in both systems as well as three hexagonal phases with mixed HTB-pyrochlore type structures. Ion exchange experiments between various alkali ions are described for several phases. Unit cell dimensions and X-ray diffraction powder patterns are reported.

Magnetohydrodynamic effects in liquid metal batteries

NASA Astrophysics Data System (ADS)

Stefani, F.; Galindo, V.; Kasprzyk, C.; Landgraf, S.; Seilmayer, M.; Starace, M.; Weber, N.; Weier, T.

2016-07-01

Liquid metal batteries (LMBs) consist of two liquid metal electrodes and a molten salt ionic conductor sandwiched between them. The density ratios allow for a stable stratification of the three layers. LMBs were already considered as part of energy conversion systems in the 1960s and have recently received renewed interest for economical large-scale energy storage. In this paper, we concentrate on the magnetohydrodynamic aspects of this cell type with special focus on electro-vortex flows and possible effects of the Tayler instability.

Solid oxide fuel cells having porous cathodes infiltrated with oxygen-reducing catalysts

DOEpatents

Liu, Meilin; Liu, Ze; Liu, Mingfei; Nie, Lifang; Mebane, David Spencer; Wilson, Lane Curtis; Surdoval, Wayne

2014-08-12

Solid-oxide fuel cells include an electrolyte and an anode electrically coupled to a first surface of the electrolyte. A cathode is provided, which is electrically coupled to a second surface of the electrolyte. The cathode includes a porous backbone having a porosity in a range from about 20% to about 70%. The porous backbone contains a mixed ionic-electronic conductor (MIEC) of a first material infiltrated with an oxygen-reducing catalyst of a second material different from the first material.

Dynamics and Tolerance of Superionics in Extreme Environment

NASA Astrophysics Data System (ADS)

Annamareddy, Venkata Ajay Krishna Choudary

Superionic conductors are multi-component solid-state systems in which one sub-lattice exhibits exceptional ionic conductivity, which is comparable to molten state; among other things, the high ionic conductivity facilitates their use as solid-state electrolytes. Uranium di-oxide (UO 2)--the material of choice for fuel in most nuclear reactors--also shows superionic behavior, although very little is understood currently on the fast ion transport in UO2, and its implication. This dissertation aims to provide a better understanding of the dynamical characteristics of superionic conductors under both equilibrium and non-equilibrium thermodynamic conditions. In the first part, the emphasis is on equilibrium fluctuations and associated properties of Type II superionic conductors. Using atomistic simulations as well as available neutron and x-ray scattering data, the order-disorder transition or onset of superionic state for Type II conductors at a certain characteristic temperature (Talpha) is first revealed. Talpha marks a structural and kinetic crossover from a crystalline state to a semi-ordered state and is clearly different from the well-known thermodynamic superionic transition (T lambda). Though not favored by entropic forces, collective and cooperative dynamical effects, reminiscent of glassy states, are manifested in the temperature range spanned by Talpha and T lambda. Using atomistic simulations, dynamical heterogeneity (DH)--presence of clustered mobile and immobile regions in a static-homogeneous system--a ubiquitous feature of supercooled liquids and glassy states, is shown to germinate at Talpha. Using reliable metrics, the DH is shown to strengthen with increasing temperature, peak at an intermediate temperature between Talpha and Tlambda , and then recede. This manifestation of DH in superionics markedly differs from that in supercooled liquids through its initial growth against the destabilizing entropic barriers. Atomistic simulations further show that DH in superionics arises from facilitated dynamics, or the phenomenon of dynamic facilitation (DF). Using mobility transfer function, which gives the probability of a neighbor of a mobile ion becoming mobile relative to that of a random ion becoming mobile, it is shown that mobility propagates continuously to the neighboring ions with the strength of the DF increasing at the order-disorder temperature ( Talpha), exhibiting a maximum at an intermediate temperature, and then decreasing as the temperature approaches T lambda. This waxing and waning behavior with temperature is nearly identical to the variation of DH. Thus the close correspondence between DH and DF strongly indicates that DF underpins the heterogeneous dynamics in Type II superionic conductors. In a dynamically facilitated system, a jammed region can become unjammed only if it is physically adjacent to a mobile region. Remarkably, a string-like displacement of ions, the quintessential mode of particle mobility in jammed systems, is shown to operate in Type II superionics as well. The probability distribution of the length of the string is shown to vary exponentially, which is identical to that observed in supercooled and jammed states. Thus the demonstration of DH, DF and string-like cooperative ionic displacements in superionics that closely parallel the dynamic characteristics of supercooled liquids and glassy states, significantly augments the already existing but scant list of phenomenological similarities between these two distinct types of materials. The second part of this dissertation deals with non-equilibrium displacement-cascade simulations of UO2 that is used as a nuclear fuel. UO2 is known to resist amorphization even when subjected to intense nuclear radiations; analysis based on structure and energy does explain this behavior from a thermodynamic perspective. Radiation is inherently dynamic (non-equilibrium), and thus it is pertinent to understand the dynamics of the displaced ions during the annealing process. In this dissertation, the mechanism of dynamic recovery following a radiation knock at the atomistic level is investigated. It is shown that oxygen ions following a radiation perturbation exhibit correlated motion, which is similar to that in high temperature superionic state. Quite remarkably, the displaced oxygen ions also undergo fast recovery to their native lattice sites through collective string-like displacements that show an exponential distribution. Thus the superionic characteristics of UO2 under equilibrium conditions are also instrumental in fast defect recovery following a radiation perturbation.

Dielectric relaxation and electrical conductivity in Bi 5NbO 10 oxygen ion conductors prepared by a modified sol-gel process

NASA Astrophysics Data System (ADS)

Hou, Jungang; Vaish, Rahul; Qu, Yuanfang; Krsmanovic, Dalibor; Varma, K. B. R.; Kumar, R. V.

Crystalline Bi 5NbO 10 nanoparticles have been achieved through a modified sol-gel process using a mixture of ethylenediamine and ethanolamine as a solvent. The Bi 5NbO 10 nanoparticles were characterized by X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DSC/TG), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and Raman spectroscopy. The results showed that well-dispersed 5-60 nm Bi 5NbO 10 nanoparticles were prepared through heat-treating the precursor at 650 °C and the high density pellets were obtained at temperatures lower than those commonly employed. The frequency and temperature dependence of the dielectric constant and the electrical conductivity of the Bi 5NbO 10 solid solutions were investigated in the 0.1 Hz to 1 MHz frequency range. Two distinct relaxation mechanisms were observed in the plots of dielectric loss and the imaginary part of impedance (Z″) versus frequency in the temperature range of 200-350 °C. The dielectric constant and the loss in the low frequency regime were electrode dependent. The ionic conductivity of Bi 5NbO 10 solid solutions at 700 °C is 2.86 Ω -1 m -1 which is in same order of magnitude for Y 2O 3-stabilized ZrO 2 ceramics at same temperature. These results suggest that Bi 5NbO 10 is a promising material for an oxygen ion conductor.

A tale of two sites: On defining the carrier concentration in garnet-based ionic conductors for advanced Li batteries

DOE PAGES

Thompson, Travis; Sharafi, Asma; Johannes, Michelle D.; ...

2015-03-21

Solid electrolytes based on the garnet crystal structure have recently been identified as a promising material to enable advance Li battery cell chemistries because of the unprecedented combination of high ionic conductivity and electrochemical stability against metallic Li. To better understand the mechanisms that give rise to high conductivity, the goal of this work is to correlate Li site occupancy with Li-ion transport. Toward this goal, the Li site occupancy is studied in cubic garnet as a function of Li concentration over the compositions range: Li 7-xLa 3Zr 2-xTa xO 12 (x = 0.5, 0.75, and 1.5). The distribution ofmore » Li between the two interstitial sites (24d and 96h) is determined using neutron and synchrotron diffraction. The bulk conductivity is measured on >97% relative density polycrystalline specimens to correlate Li-ion transport as a function of Li site occupancy. It is determined that the conductivity changes nonlinearly with the occupancy of the octahedral (96h) Li site. It is shown that the effective carrier concentration is dependent on the Li site occupancy and suggests that this is a consequence of significant carrier-carrier coulombic interactions. Moreover, the observation of maximum conductivity near Li = 6.5 mol is explained.« less

Durable electrooptic devices comprising ionic liquids

DOEpatents

Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Cronin,; John, P [Tucson, AZ; Tonazzi, Juan C. L. [Tucson, AZ; Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM

2009-12-15

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes. Some of the electrolyte solutions color to red when devices employing the solutions are powered, leading to red or neutral electrooptic devices.

Structural and electrochemical properties of La 0.8Sr 0.2Ga 1-xFe xO 3

NASA Astrophysics Data System (ADS)

Mori, Kazuhiro; Onodera, Yohei; Kiyanagi, Ryoji; Richardson, James W.; Itoh, Keiji; Sugiyama, Masaaki; Kamiyama, Takashi; Fukunaga, Toshiharu

2009-02-01

Mixed ionic-electronic conductor of Fe doped lanthanum gallate, La 0.8Sr 0.2Ga 1-xFe xO 3, has been studied by the dc four-probe method and the neutron powder diffraction. In the electrical conductivity measurement at RT, insulator-metal transition-like phenomenon was observed at around x˜0.35; this suggests an existence of the percolation limit for the electronic conductivity. Simultaneously, a bond length between O atoms, lO-O, in a MO 6 octahedron (M dbnd Ga 1-xFe x) drastically expands over x˜0.4, according to the result of crystal structure refinement based on the hexagonal phase. Such a drastic expansion in the lO-O would induce the decrease in the oxygen ionic conductivity.

Potentiometric chip-based multipumping flow system for the simultaneous determination of fluoride, chloride, pH, and redox potential in water samples.

PubMed

Chango, Gabriela; Palacio, Edwin; Cerdà, Víctor

2018-08-15

A simple potentiometric chip-based multipumping flow system (MPFS) has been developed for the simultaneous determination of fluoride, chloride, pH, and redox potential in water samples. The proposed system was developed by using a poly(methyl methacrylate) chip microfluidic-conductor using the advantages of flow techniques with potentiometric detection. For this purpose, an automatic system has been designed and built by optimizing the variables involved in the process, such as: pH, ionic strength, stirring and sample volume. This system was applied successfully to water samples getting a versatile system with an analysis frequency of 12 samples per hour. Good correlation between chloride and fluoride concentration measured with ISE and ionic chromatography technique suggests satisfactory reliability of the system. Copyright © 2018 Elsevier B.V. All rights reserved.

Durable Electrooptic Devices Comprising Ionic Liquids

DOEpatents

Burrell, Anthony K.; Agrawal, Anoop; Cronin, John P.; Tonazzi, Juan C. L.; Warner, Benjamin P.; McCleskey, T. Mark

2008-11-11

Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes. Some of the electrolyte solutions color to red when devices employing the solutions are powered, leading to red or neutral electrooptic devices.

AC impedance spectroscopy of NASICON type Na3Fe2(PO4)3 ceramic

NASA Astrophysics Data System (ADS)

Mandal, Biswajit; Thakur, A. K.

2018-05-01

Super ionic conductors (e.g.; A3M2(XO4)3, A=Li, Na) have received attention in applied research due to their interesting electrochemical property and inherently high ionic conductivity [1]. However, structural and compatibility requirements for fast ion transport is stringent and it plays a crucial role. In A3M2(XO4)3, a suitable cage formation in the crystal framework due to corner sharing arrangement of XO4 tetrahedra and MO6 octahedra creates voids that acts as host/guest site for cation transport. In this work, we report Nasicon structure Na3Fe2(PO4)3 (NFP) prepared via sol-gel route mediated by citric acid. Structural analysis confirmed that NFP sample belongs to monoclinic crystal structure having Cc space group (S. G. No 9) with lattice parameters, a=15.106 Å, b=8.722 Å, c=8.775 Å and β=124.96°. Electrical properties of the prepared sample have been studied by AC impedance spectroscopy technique. The AC conductivity results indicated typical signature of ionically conducting system.

Simulating Charge Transport in Solid Oxide Mixed Ionic and Electronic Conductors: Nernst-Planck Theory vs Modified Fick's Law

DOE PAGES

Jin, Xinfang; White, Ralph E.; Huang, Kevin

2016-10-04

With the assumption that the Fermi level (electrochemical potential of electrons) is uniform across the thickness of a mixed ionic and electronic conducting (MIEC) electrode, the charge-transport model in the electrode domain can be reduced to the modified Fick’s first law, which includes a thermodynamic factor A. A transient numerical solution of the Nernst-Planck theory was obtained for a symmetric cell with MIEC electrodes to illustrate the validity of the assumption of a uniform Fermi level. Subsequently, an impedance numerical solution based on the modified Fick’s first law is compared with that from the Nernst-Planck theory. The results show thatmore » Nernst-Planck charge-transport model is essentially the same as the modified Fick’s first law model as long as the MIEC electrodes have a predominant electronic conductivity. However, because of the invalidity of the uniform Fermi level assumption for aMIEC electrolyte with a predominant ionic conductivity, Nernst-Planck theory is needed to describe the charge transport behaviors.« less

Acid and alkali doped PBI electrolyte in electrochemical system

NASA Astrophysics Data System (ADS)

Xing, Baozhong

In this work the conductivity of blank PBI membrane, acid doped PBI and alkaline doped PBI was systematically studied. A new methodology for sorption kinetics study in electrolyte solution has been established by monitoring the conductivity change during the sorption process. The model of the doping process and mechanism of conductivity are proposed. The performance of PBI (doped under optimum conditions) in fuel cell as PEM was evaluated. The experimental results show that the blank PBI in acid solution is an ionic insulator. It clarified the long time confusion in this area. The acid doped PBI membrane is an ionic conductor. The conductivity increases with the concentration of the acid solution. In high concentration acid solution, the conductivity increases with the type of acid in the order: H2SO 4 > H3PO4 > HClO4 > HNO3 > HCl. The kinetics of the doping process was studied, by a continuous method. The ionic conductivity mechanism was established. The PBI membranes doped with H2SO4 and H3PO4 exhibit better performance than NafionRTM. The doped FBI has more resistance to CO poison. 3% CO in H2 has little effect on the H3PO 4 doped PBI membrane at 185°C. The conductivity of the alkali doped PBI membrane changes with the concentration of the alkaline solution and the type of the alkalis. The conductivity has a maximum in KOH and NaOH solution. The maximum conductivity in KOH is higher than in NaOH and LiOH. It is about 5 times of that of NafionRTM in alkaline solution. The two-step sorption process in alkaline solution was observed. The first step is the permeation process of the alkalis in the PBI membrane. The permeation is the results of diffusion and interaction. It is concluded that the permeation process is controlled by the rate of interaction between the alkali and PBI molecule. The second step is the relaxation process in the membrane. This step contributes more to the conductivity for the membrane than the first step. The ionic conductivity mechanism was established. In solution the cations and OH- all participate in the transport of current. It is the OH- that breaks the bonds between PBI molecules and enables the cations pass through the membrane. The performance of alkali doped PBI (doped under optimum conditions) in fuel cell as PEM is as good as NafionRTM.

Glass transition dynamics and conductivity scaling in ionic deep eutectic solvents: The case of (acetamide + lithium nitrate/sodium thiocyanate) melts

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

Tripathy, Satya N., E-mail: satyanarayantripathy@gmail.com; Wojnarowska, Zaneta; Knapik, Justyna

2015-05-14

A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10{sup −1}-10{sup 6} Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transitionmore » temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai’s coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors.« less

Extensive Evaluation of the Conductor-like Screening Model for Real Solvents Method in Predicting Liquid-Liquid Equilibria in Ternary Systems of Ionic Liquids with Molecular Compounds.

PubMed

Paduszyński, Kamil

2018-04-12

A conductor-like screening model for real solvents (COSMO-RS) is nowadays one of the most popular and commonly applied tools for the estimation of thermodynamic properties of complex fluids. The goal of this work is to provide a comprehensive review and analysis of the performance of this approach in calculating liquid-liquid equilibrium (LLE) phase diagrams in ternary systems composed of ionic liquid and two molecular compounds belonging to diverse families of chemicals (alkanes, aromatics, S/N-compounds, alcohols, ketones, ethers, carboxylic acid, esters, and water). The predictions are presented for extensive experimental database, including 930 LLE data sets and more than 9000 data points (LLE tie lines) reported for 779 unique ternary mixtures. An impact of the type of molecular binary subsystem on the accuracy of predictions is demonstrated and discussed on the basis of representative examples. The model's capability of capturing qualitative trends in the LLE distribution ratio and selectivity is also checked for a number of structural effects. Comparative analysis of two levels of quantum chemical theory (BP-TZVP-COSMO vs BP-TZVPD-FINE) for the input molecular data for COSMO-RS is presented. Finally, some general recommendations for the applicability of the model are indicated based on the analysis of the global performance as well as on the results obtained for systems relevant from the point of view of important separation problems.

Hexacopper(I) phosphorus(V) bromide penta(selenide/sulfide), Cu6P(Se0.7S0.3)5Br.

PubMed

Gagor, A; Pietraszko, A; Panko, V V

2008-04-01

This work illustrates possible diffusion paths for Cu(I) ions in a highly disordered structure of a superionic conductor of the argyrodite family. The Cu(6)P(Se(0.7)S(0.3))(5)Br cubic structure is built from a [P(Se(0.7)S(0.3))(5)Br] framework in which Cu(I) ions are distributed in various tetrahedral, triangular and linear sites. There are two types of disorder in the structure. The first type results from the fact that there are fewer Cu(I) ions than the number of positions available for them in the unit cell. The second type is due to the static distribution of Se and S atoms in the [P(Se(0.7)S(0.3))(5)Br] framework. The title compound is a solid solution of two efficient ionic conductors, namely Cu(6)PSe(5)Br and Cu(6)PS(5)Br, in which high ionic conductivity results from order-disorder phenomena in the copper substructure. To shed light on the distribution of Cu(I) ions in disordered Cu(6)P(Se(0.7)S(0.3))(5)Br, we refined their positions using a combination of a nonharmonic approach and a split-atom model. At room temperature, Cu(I) ions show strong anharmonic vibrations along the edge of the (Br)(4) tetrahedra. The probability density functions of the Cu(I) ions overlap and reveal possible diffusion paths.

How to interpret current-voltage relationships of blocking grain boundaries in oxygen ionic conductors.

PubMed

Kim, Seong K; Khodorov, Sergey; Chen, Chien-Ting; Kim, Sangtae; Lubomirsky, Igor

2013-06-14

A new model based on a linear diffusion equation is proposed to explain the current-voltage characteristics of blocking grain boundaries in Y-doped CeO2 in particular. One can also expect that the model can be applicable to the ionic conductors with blocking grain boundaries, in general. The model considers an infinitely long chain of identical grains separated by grain boundaries, which are treated as regions in which depletion layers of mobile ions are formed due to trapping of immobile charges that do not depend on the applied voltage as well as temperature. The model assumes that (1) the grain boundaries do not represent physical blocking layers, which implies that if there is a second phase at the grain boundaries, then it is too thin to impede ion diffusion and (2) the ions follow Boltzmann distribution throughout the materials. Despite its simplicity, the model successfully reproduces the "power law": current proportional to voltage power n and illustrated with the experimental example of Y-doped ceria. The model also correctly predicts that the product nT, where T is the temperature in K, is constant and is proportional to the grain boundary potential as long as the charge at the grain boundaries remains trapped. The latter allows its direct determination from the current-voltage characteristics and promises considerable simplification in the analysis of the electrical characteristics of the grain boundaries with respect to the models currently in use.

Dynamic mechanical control of local vacancies in NiO thin films

NASA Astrophysics Data System (ADS)

Seol, Daehee; Yang, Sang Mo; Jesse, Stephen; Choi, Minseok; Hwang, Inrok; Choi, Taekjib; Park, Bae Ho; Kalinin, Sergei V.; Kim, Yunseok

2018-07-01

The manipulation of local ionic behavior via external stimuli in oxide systems is of great interest because it can help in directly tuning material properties. Among external stimuli, mechanical force has attracted intriguing attention as novel stimulus for ionic modulation. Even though effectiveness of mechanical force on local ionic modulation has been validated in terms of static effect, its real-time i.e., dynamic, behavior under an application of the force is barely investigated in spite of its crucial impact on device performance such as force or pressure sensors. In this study, we explore dynamic ionic behavior modulated by mechanical force in NiO thin films using electrochemical strain microscopy (ESM). Ionically mediated ESM hysteresis loops were significantly varied under an application of mechanical force. Based on these results, we were able to investigate relative relationship between the force and voltage effects on ionic motion and, further, control effectively ionic behavior through combination of mechanical and electrical stimuli. Our results can provide comprehensive information on the effect of mechanical forces on ionic dynamics in ionic systems.

Dynamic mechanical control of local vacancies in NiO thin films.

PubMed

Seol, Daehee; Yang, Sang Mo; Jesse, Stephen; Choi, Minseok; Hwang, Inrok; Choi, Taekjib; Park, Bae Ho; Kalinin, Sergei V; Kim, Yunseok

2018-07-06

The manipulation of local ionic behavior via external stimuli in oxide systems is of great interest because it can help in directly tuning material properties. Among external stimuli, mechanical force has attracted intriguing attention as novel stimulus for ionic modulation. Even though effectiveness of mechanical force on local ionic modulation has been validated in terms of static effect, its real-time i.e., dynamic, behavior under an application of the force is barely investigated in spite of its crucial impact on device performance such as force or pressure sensors. In this study, we explore dynamic ionic behavior modulated by mechanical force in NiO thin films using electrochemical strain microscopy (ESM). Ionically mediated ESM hysteresis loops were significantly varied under an application of mechanical force. Based on these results, we were able to investigate relative relationship between the force and voltage effects on ionic motion and, further, control effectively ionic behavior through combination of mechanical and electrical stimuli. Our results can provide comprehensive information on the effect of mechanical forces on ionic dynamics in ionic systems.

Sodium vanadium titanium phosphate electrode for symmetric sodium-ion batteries with high power and long lifespan

PubMed Central

Wang, Dongxue; Bie, Xiaofei; Fu, Qiang; Dixon, Ditty; Bramnik, Natalia; Hu, Yong-Sheng; Fauth, Francois; Wei, Yingjin; Ehrenberg, Helmut; Chen, Gang; Du, Fei

2017-01-01

Sodium-ion batteries operating at ambient temperature hold great promise for use in grid energy storage owing to their significant cost advantages. However, challenges remain in the development of suitable electrode materials to enable long lifespan and high rate capability. Here we report a sodium super-ionic conductor structured electrode, sodium vanadium titanium phosphate, which delivers a high specific capacity of 147 mA h g−1 at a rate of 0.1 C and excellent capacity retentions at high rates. A symmetric sodium-ion full cell demonstrates a superior rate capability with a specific capacity of about 49 mA h g−1 at 20 C rate and ultralong lifetime over 10,000 cycles. Furthermore, in situ synchrotron diffraction and X-ray absorption spectroscopy measurement are carried out to unravel the underlying sodium storage mechanism and charge compensation behaviour. Our results suggest the potential application of symmetric batteries for electrochemical energy storage given the superior rate capability and long cycle life. PMID:28660877

Sodium vanadium titanium phosphate electrode for symmetric sodium-ion batteries with high power and long lifespan.

PubMed

Wang, Dongxue; Bie, Xiaofei; Fu, Qiang; Dixon, Ditty; Bramnik, Natalia; Hu, Yong-Sheng; Fauth, Francois; Wei, Yingjin; Ehrenberg, Helmut; Chen, Gang; Du, Fei

2017-06-29

Sodium-ion batteries operating at ambient temperature hold great promise for use in grid energy storage owing to their significant cost advantages. However, challenges remain in the development of suitable electrode materials to enable long lifespan and high rate capability. Here we report a sodium super-ionic conductor structured electrode, sodium vanadium titanium phosphate, which delivers a high specific capacity of 147 mA h g -1 at a rate of 0.1 C and excellent capacity retentions at high rates. A symmetric sodium-ion full cell demonstrates a superior rate capability with a specific capacity of about 49 mA h g -1 at 20 C rate and ultralong lifetime over 10,000 cycles. Furthermore, in situ synchrotron diffraction and X-ray absorption spectroscopy measurement are carried out to unravel the underlying sodium storage mechanism and charge compensation behaviour. Our results suggest the potential application of symmetric batteries for electrochemical energy storage given the superior rate capability and long cycle life.

Ionic conductivity and dielectric relaxation in Y doped La2Mo2O9 oxide-ion conductors

NASA Astrophysics Data System (ADS)

Paul, T.; Ghosh, A.

2014-10-01

In this work, we have studied electrical conductivity and dielectric properties of polycrystalline La2-xYxMo2O9 (0.05 ≤ x ≤ 0.3) compounds in the temperature range from 358 K to 1088 K and the frequency range from 10 Hz to 3 GHz. The bulk and grain boundary contributions to the overall conductivity of these compounds show Arrhenius type behavior at low temperatures. The random free-energy barrier model has been used to analyze the frequency dependence of the conductivity. The charge carrier relaxation time and its activation energy have been determined from the analysis of the conductivity spectra using this model. The results obtained from the random free-energy barrier model satisfy Barton-Nakajima-Namikawa relation. The conduction mechanism has been also predicted using random free-energy barrier model and the scaling formalism. We have observed that the dielectric relaxation peaks arise from the diffusion of oxygen ions via vacancies.

Mechanically stable, high-aspect-ratio, multifilar, wound, ribbon-type conductor and method for manufacturing same

DOEpatents

Cottingham, J.G.

1982-03-15

A mechanically stable, wound, multifilar, ribbon-type conductor is described having a cross-sectional aspect ratio which may be greater than 12:1, comprising a plurality of conductive strands wound to form a flattened helix containing a plastic strip into which the strands have been pressed so as to form a bond between the strip and the strands. The bond mechanically stabilizes the conductor under tension, preventing it from collapsing into a tubular configuration. In preferred embodiments the plastic strip may be polytetrafluoroethylene, and the conductive strands may be formed from a superconductive material. Conductors in accordance with the present invention may be manufactured by winding a plurality of conductive strands around a hollow mandrel; the cross-section of a hollow mandrel; the cross-section of the mandrel continuously varying from substnatially circular to a high aspect ratio elipse while maintaining a constant circumference. The wound conductive strands are drawn from the mandrel as a multifilar helix while simultaneously a plastic strip is fed through the hollow mandrel so that it is contained within the helix as it is withdrawn from the mandrel. The helical conductor is then compressed into a ribbon-like form and the strands are bonded to the plastic strip by a combination of heat and pressure.

Mechanically stable, high aspect ratio, multifilar, wound, ribbon-type conductor and method for manufacturing same

DOEpatents

Cottingham, James G.

1987-01-01

A mechanically stable, wound, multifilar, ribbon-type conductor having a cross-sectional aspect ratio which may be greater than 12:1, comprising a plurality of conductive strands wound to form a flattened helix containing a plastic strip into which the strands have been pressed so as to form a bond between the strip and the strands. The bond mechanically stabilizes the conductor under tension, preventing it from collapsing into a tubular configuration. In preferred embodiments the plastic strip may be polytetrafluoroethylene, and the conductive strands may be formed from a superconductive material. Conductors in accordance with the present invention may be manufactured by winding a plurality of conductive strands around a hollow mandrel; the cross-section of a hollow mandrel; the cross-section of the mandrel continuously varying from substantially circular to a high aspect ratio elipse while maintaining a constant circumference. The wound conductive strands are drawn from the mandrel as a multifilar helix while simultaneously a plastic strip is fed through the hollow mandrel so that it is contained within the helix as it is withdrawn from the mandrel. The helical conductor is then compressed into a ribbon-like form and the strands are bonded to the plastic strip by a combination of heat and pressure.

Mechanically stable, high aspect ratio, multifilar, wound, ribbon-type conductor and method for manufacturing same

DOEpatents

Cottingham, James G.

1987-11-03

A mechanically stable, wound, multifilar, ribbon-type conductor having a cross-sectional aspect ratio which may be greater than 12:1, comprising a plurality of conductive strands wound to form a flattened helix containing a plastic strip into which the strands have been pressed so as to form a bond between the strip and the strands. The bond mechanically stabilizes the conductor under tension, preventing it from collapsing into a tubular configuration. In preferred embodiments the plastic strip may be polytetrafluoroethylene, and the conductive strands may be formed from a superconductive material. Conductors in accordance with the present invention may be manufactured by winding a plurality of conductive strands around a hollow mandrel; the cross-section of a hollow mandrel; the cross-section of the mandrel continuously varying from substantially circular to a high aspect ratio elipse while maintaining a constant circumference. The wound conductive strands are drawn from the mandrel as a multifilar helix while simultaneously a plastic strip is fed through the hollow mandrel so that it is contained within the helix as it is withdrawn from the mandrel. The helical conductor is then compressed into a ribbon-like form and the strands are bonded to the plastic strip by a combination of heat and pressure.

Design and synthesis of the superionic conductor Na10SnP2S12

NASA Astrophysics Data System (ADS)

Richards, William D.; Tsujimura, Tomoyuki; Miara, Lincoln J.; Wang, Yan; Kim, Jae Chul; Ong, Shyue Ping; Uechi, Ichiro; Suzuki, Naoki; Ceder, Gerbrand

2016-03-01

Sodium-ion batteries are emerging as candidates for large-scale energy storage due to their low cost and the wide variety of cathode materials available. As battery size and adoption in critical applications increases, safety concerns are resurfacing due to the inherent flammability of organic electrolytes currently in use in both lithium and sodium battery chemistries. Development of solid-state batteries with ionic electrolytes eliminates this concern, while also allowing novel device architectures and potentially improving cycle life. Here we report the computation-assisted discovery and synthesis of a high-performance solid-state electrolyte material: Na10SnP2S12, with room temperature ionic conductivity of 0.4 mS cm-1 rivalling the conductivity of the best sodium sulfide solid electrolytes to date. We also computationally investigate the variants of this compound where tin is substituted by germanium or silicon and find that the latter may achieve even higher conductivity.

Synthesis, crystal structure and ionic conductivity of the Ba3Mo1-xWxNbO8.5 solid solution

NASA Astrophysics Data System (ADS)

Bernasconi, Andrea; Tealdi, Cristina; Mühlbauer, Martin; Malavasi, Lorenzo

2018-02-01

Ba3MoNbO8.5 compound has been recently discovered as novel oxide ionic conductor with a structure that is a hybrid between 9R hexagonal perovskite and palmierite. In this work, the full substitution of Mo with W has been demonstrated as possible, without altering significantly the conductivity of the material. The crystal structure of the Ba3Mo1-xWxNbO8.5 solid solution (with x equals 0, 0.25, 0.5, 0.75 and 1) has been investigated by X-ray powder diffraction, showing a reduction of the unit cell by increasing the molybdenum content, despite the larger size of tungsten compared to molybdenum. Neutron powder diffraction measurements have been performed, indicating different levels of contribution of 9R polytype and of palmierite to the hybrid structure of the material as a function of the W-content.

High Electromechanical Response of Ionic Polymer Actuators with Controlled-Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes

PubMed Central

Liu, Sheng; Liu, Yang; Cebeci, Hülya; de Villoria, Roberto Guzmán; Lin, Jun-Hong

2011-01-01

Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here our experiments demonstrate that the VA-CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 volts). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultra-high volume fraction VA-CNTs to further enhanced performance. PMID:21765822

Measurement of the Onsager coefficients of mixed ionic-electronic conduction in oxides

NASA Astrophysics Data System (ADS)

Lee, Doh-Kwon; Yoo, Han-Ill

2007-06-01

In the phenomenon of mixed ionic-electronic conduction in solid state, a flow of mobile ions (Ji) may be induced not only directly by their own electrochemical potential gradient (∇ηi) , but also indirectly by that of electrons (∇ηe) , and vice versa for a flow of electrons (Je) or Jm=-Lmn∇ηn (m,n=i,e) . We have recently succeeded in determining experimentally all the four Onsager coefficients Lmn on the system of TiO2 , and reported [Phys. Rev. Lett. 97, 255901 (2006)] that the Onsager reciprocity is verified within 1.3% error bound (Lie/Lei=0.993±0.013) and contrary to the general belief, the cross coefficient is not only not negligible but also even larger than a direct one (1.5⩽Lie/Lii⩽3.7) . This paper details the experimental technique which allows one to measure all the Onsager coefficients in a mixed conductor oxide.

Design and synthesis of the superionic conductor Na10SnP2S12.

PubMed

Richards, William D; Tsujimura, Tomoyuki; Miara, Lincoln J; Wang, Yan; Kim, Jae Chul; Ong, Shyue Ping; Uechi, Ichiro; Suzuki, Naoki; Ceder, Gerbrand

2016-03-17

Sodium-ion batteries are emerging as candidates for large-scale energy storage due to their low cost and the wide variety of cathode materials available. As battery size and adoption in critical applications increases, safety concerns are resurfacing due to the inherent flammability of organic electrolytes currently in use in both lithium and sodium battery chemistries. Development of solid-state batteries with ionic electrolytes eliminates this concern, while also allowing novel device architectures and potentially improving cycle life. Here we report the computation-assisted discovery and synthesis of a high-performance solid-state electrolyte material: Na10SnP2S12, with room temperature ionic conductivity of 0.4 mS cm(-1) rivalling the conductivity of the best sodium sulfide solid electrolytes to date. We also computationally investigate the variants of this compound where tin is substituted by germanium or silicon and find that the latter may achieve even higher conductivity.

Proton conduction of polyAMPS brushes on titanate nanotubes

PubMed Central

Feng, Jun; Huang, Yaqin; Tu, Zhengkai; Zhang, Haining; Pan, Mu; Tang, Haolin

2014-01-01

Proton conducting materials having reasonable proton conductivity at low humidification conditions are critical for decrease in system complexity and improvement of power density for polymer electrolyte membrane fuel cells. This study shows that polyelectrolyte brushes on titanate nanotubes formed through surface-initiated free radical polymerization exhibit less humidity-dependent proton conduction because of the high grafting density of polymer electrolyte chains and well-distribution of ionic groups. The results described in this study provide an idea for design of new proton conductors with effective ion transport served at relatively low humidification levels. PMID:25169431

Method of making sulfur tolerant composite cermet electrodes for solid oxide electrochemical cells

DOEpatents

Isenberg, Arnold O.

1989-01-01

An electrochemical apparatus is made containing an exterior electorde bonded to the exterior of a tubular, solid, oxygen ion conducting electrolyte where the electrolyte is also in contact with an interior electrode, said exterior electrode comprising particles of an electronic conductor contacting the electrolyte, where a ceramic metal oxide coating partially surrounds the particles and is bonded to the electrolyte, and where a coating of an ionic-electronic conductive material is attached to the ceramic metal oxide coating and to the exposed portions of the particles.

Sulfur tolerant composite cermet electrodes for solid oxide electrochemical cells

DOEpatents

Isenberg, Arnold O.

1987-01-01

An electrochemical apparatus is made containing an exterior electrode bonded to the exterior of a tubular, solid, oxygen ion conducting electrolyte where the electrolyte is also in contact with an interior electrode, said exterior electrode comprising particles of an electronic conductor contacting the electrolyte, where a ceramic metal oxide coating partially surrounds the particles and is bonded to the electrolyte, and where a coating of an ionic-electronic conductive material is attached to the ceramic metal oxide coating and to the exposed portions of the particles.

Preliminary Reports, Memoranda and Technical Notes of the Materials Research Council Summer Conference, La Jolla, CA

DTIC Science & Technology

1975-07-01

1298 (1974); T. Wei, S. Etemad, A. F. Garito and A. J. Heeger, Phys. Lett. 4_5a 269 (1973). G. A. Vhomas, et. al .. Solid State Comm. 0£, 000...C. Beer, Eds. (Academic Press, New York 1975) Vol. 11 (to be published). H. Fetterman et al ., IEEE Trans. MTT-22, 1013 (1974) 8. A. H. Silver...increasing temperature over extensive ranges. Such measure- ments were reported by Johnston et al .?1 for the fast ionic conductor RbAgJ,. Thermal

Facile Supramolecular Processing of Carbon Nanotubes and Polymers for Electromechanical Sensors.

PubMed

Kim, Chae Bin; Jeong, Ki Beom; Yang, Beom Joo; Song, Jong-Won; Ku, Bon-Cheol; Lee, Seunghyun; Lee, Seoung-Ki; Park, Chiyoung

2017-12-18

We herein report a facile, cost-competitive, and scalable method for producing viscoelastic conductors via one-pot melt-blending using polymers and supramolecular gels composed of carbon nanotubes (CNTs), diphenylamine (DP), and benzophenone (BP). When mixed, a non-volatile eutectic liquid (EL) produced by simply blending DP with BP (1:1 molar ratio) enabled not only the gelation of CNTs (EL-CNTs) but also the dissolution of a number of commodity polymers. To make use of these advantages, viscoelastic conductors were produced via one-pot melt-blending the EL and CNTs with a model thermoplastic elastomer, poly(styrene-b-butadiene-b-styrene) (SBS, styrene 30 wt %). The resulting composites displayed an excellent electromechanical sensory along with re-mendable properties. This simple method using cost-competitive EL components is expected to provide an alternative to the use of expensive ionic liquids as well as to facilitate the fabrication of novel composites for various purposes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

An ultraviolet responsive hybrid solar cell based on titania/poly(3-hexylthiophene).

PubMed

Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Lin, Jianming; Huang, Miaoliang; Lan, Zhang; Tang, Qunwei; Huang, Yunfang; Fan, Leqing; Yin, Shu; Sato, Tsugio

2013-01-01

Here we present an ultraviolet responsive inorganic-organic hybrid solar cell based on titania/poly(3-hexylthiophene) (TiO(2)/P3HT) heterojuction. In this solar cell, TiO(2) is an ultraviolet light absorber and electronic conductor, P3HT is a hole conductor, the light-to-electrical conversion is realized by the cooperation for these two components. Doping ionic salt in P3HT polymer can improve the photovoltaic performance of the solar cell. Under ultraviolet light irradiation with intensity of 100 mW·cm(-2), the hybrid solar cell doped with 1.0 wt.% lithium iodide achieves an energy conversion efficiency of 1.28%, which is increased by 33.3% compared to that of the hybrid solar cell without lithium iodide doping. Our results open a novel sunlight irradiation field for solar energy utilization, demonstrate the feasibility of ultraviolet responsive solar cells, and provide a new route for enhancing the photovoltaic performance of solar cells.

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

Chen, Yan; Cai, Lu; An, Ke, E-mail: kean@ornl.gov

This letter reports the correlation of anisotropy and directional conduction in the fast Li{sup +} conductor β-Li{sub 3}PS{sub 4}, one of the low-symmetry crystalline electrolyte candidates. The material has both high conductivity and good stability that serves well for the large-scale energy storage applications of all-solid-state lithium ion batteries. The anisotropic physical properties, demonstrated here by the thermal expansion coefficients, are crucial for compatibility in the solid-state system and battery performance. Neutron and X-ray powder diffraction measurements were done to determine the crystal structure and thermal stability. The crystallographic b-axis was revealed as a fast expansion direction, while negligible thermalmore » expansion was observed along the a-axis around the battery operating temperatures. The anisotropic behavior has its structural origin from the Li{sup +} conduction channels with incomplete Li occupancy and a flexible connection of LiS{sub 4} and PS{sub 4} tetrahedra within the framework. This indicates a strong correlation in the direction of the ionic transport in the low-symmetry Li{sup +} conductor.« less

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

Chen, Yan; Cai, Lu; Liu, Zengcai

Our letter reports the correlation of anisotropy and directional conduction in the fast Li + conductor β-Li 3PS 4, one of the low-symmetry crystalline electrolyte candidates. The material has both high conductivity and good stability that serves well for the large-scale energy storage applications of all-solid-state lithium ion batteries. The anisotropic physical properties, demonstrated here by the thermal expansion coefficients, are crucial for compatibility in the solid-state system and battery performance. Neutron and X-ray powder diffraction measurements were done to determine the crystal structure and thermal stability. Moreover, the crystallographic b-axis was revealed as a fast expansion direction, while negligiblemore » thermal expansion was observed along the a-axis around the battery operating temperatures. The anisotropic behavior has its structural origin from the Li + conduction channels with incomplete Li occupancy and a flexible connection of LiS 4 and PS 4 tetrahedra within the framework. This indicates a strong correlation in the direction of the ionic transport in the low-symmetry Li + conductor.« less

Improvement of chemical monitoring of water-chemistry conditions at thermal power stations based on electric conductivity and pH measurements

NASA Astrophysics Data System (ADS)

Larin, A. B.; Larin, B. M.

2016-05-01

The increased requirements to the quality of the water heat conductor for working superhigh (SHP) and supercritical (SCP) pressure power plants and promising units, including combined-cycle gas turbine (CCGT) units and power plants with ultrasupercritical parameters (USCPs), can largely be satisfied through specific electric conductivity and pH measurements for cooled heat conductor samples combined with calculations of ionic equilibria and indirect measurements of several specified and diagnostic parameters. The possibility of calculating the ammonia and chloride concentrations and the total concentration of hardness and sodium cations in the feed water of drum-type boilers and the phosphate and salt contents in boiler water was demonstrated. An equation for evaluating the content of potentially acid substances in the feed water of monotube boilers was suggested. The potential of the developed procedure for evaluating the state of waterchemistry conditions (WCCs) in power plants with CCGT units was shown.

Short-lived K2S Molecules in Superionic Potassium Sulfide

NASA Astrophysics Data System (ADS)

Okeya, Yusuke; Tsumuraya, Kazuo

2015-03-01

The first principles molecular dynamics method allows us to elucidate the formation of short-lived K2S molecular states in superionic potassium sulfide. The covalent and the Coulomb bonds exist between the ionized mobile potassiums and the ionized immobile sulfurs. Both the bonds induces indirect covalent and indirect Coulomb attractions between the di-interstitial potassiums on the mid-sulfurs, which forms the short-lived K2S molecular states. The covalent electron density also exists between short-lived potassium dimers. The three attractions reduce Haven's ratios of the potassiums in the conductor. The molecule formation indicates the electronic state of the conductor is intermediate between the ionic and covalent crystals. The absence of the long-lived potassium dimers implies a failure of the caterpillar diffusion model or the Frenkel-Kontorova chain model for the superionic diffusion of the potassiums in the sulfide. The incompletely ionized cations and anions reduce the Coulomb attractions between them which induces the sublattice melting of smaller size of the potassiums than the sulfurs.

An ultraviolet responsive hybrid solar cell based on titania/poly(3-hexylthiophene)

PubMed Central

Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Lin, Jianming; Huang, Miaoliang; Lan, Zhang; Tang, Qunwei; Huang, Yunfang; Fan, Leqing; Yin, Shu; Sato, Tsugio

2013-01-01

Here we present an ultraviolet responsive inorganic-organic hybrid solar cell based on titania/poly(3-hexylthiophene) (TiO2/P3HT) heterojuction. In this solar cell, TiO2 is an ultraviolet light absorber and electronic conductor, P3HT is a hole conductor, the light-to-electrical conversion is realized by the cooperation for these two components. Doping ionic salt in P3HT polymer can improve the photovoltaic performance of the solar cell. Under ultraviolet light irradiation with intensity of 100 mW·cm−2, the hybrid solar cell doped with 1.0 wt.% lithium iodide achieves an energy conversion efficiency of 1.28%, which is increased by 33.3% compared to that of the hybrid solar cell without lithium iodide doping. Our results open a novel sunlight irradiation field for solar energy utilization, demonstrate the feasibility of ultraviolet responsive solar cells, and provide a new route for enhancing the photovoltaic performance of solar cells. PMID:23412470

Flexible transparent conductors based on metal nanowire networks

DOE PAGES

Guo, Chuan Fei; Ren, Zhifeng

2015-04-01

Few conductors are transparent and flexible. Metals have the best electrical conductivity, but they are opaque and stiff in bulk form. However, metals can be transparent and flexible when they are very thin or properly arranged on the nanoscale. This review focuses on the flexible transparent conductors based on percolating networks of metal. Specifically, we discuss the fabrication, the means to improve the electrical conductivity, the large stretchability and its mechanism, and the applications of these metal networks. We also suggest some criteria for evaluating flexible transparent conductors and propose some new research directions in this emerging field.

Batch fabrication process development for ferrite logic conductors

NASA Technical Reports Server (NTRS)

Heckler, C. H., Jr.; Bhiwandker, N. C.

1972-01-01

A process for fabricating ultrareliable magnetic ferrite logic circuits is described in which the conductors are formed by a combination of two batch type processes - photolithography and electroplating - and a mechanized writing process for completing conductors in the third dimension. Up to 4 turns, through an aperture 1 mm in diameter, are formed by the described process. The number of joints in the conductors is reduced by use of this process to only those which are required for input, output and power connections of a logic block. To demonstrate feasibility, 8-stage magnetic ring counter circuits have been fabricated.

Mixed ionic-electronic conductors for electrodes of barium cerate-based SOFCS

NASA Astrophysics Data System (ADS)

Wu, Zhonglin

Gadolinium doped barium cerates (BCGs) have been identified as promising electrolyte materials for intermediate-temperature solid oxide fuel cells (SOFCs). It is crucial to develop compatible electrode materials for such electrolytes. Mixed ionic-electronic conductor (MIEC) electrode materials developed for SOFCs based on yttrium-stabilized zirconia (YSZ) may be used as electrode materials for BCG-based SOFCs; but a careful re-evaluation is required due to the intrinsic differences between BCG and YSZ. The performance of these electrode materials depends critically the transport of ionic and electronic species as well as gas. Accordingly, a profound understanding of transport in MIEC electrodes is imperative to effective design of high performance SOFCs. In this thesis, ambipolar transport in composite MIEC electrodes has been modeled using percolation theory to predict the effect of volume fractions of constituent phases and porosity on ambipolar conductivity. Transport and electrode kinetics of homogeneous MIEC electrodes have also been formulated under a steady-state condition to predict the distributions of ionic defects and current carried by each defect in such electrodes. Effects of catalytic properties, transport properties, and microstructure of porous electrodes and interfaces on the electrode performance are investigated. Under the guidelines of the theoretical modeling, several MIEC electrode materials are developed. Lasb{1-x}Srsb{x}Cosb{1-x}Fesb{y}Osb{3-delta} homogeneous materials are studied as cathode materials. However, the interfacial resistance seems too high due to the lack of catalytic activity at intermediate temperatures. Results indicate that Ag-Bisb{1.5}Ysb{0.5}Osb3 composite MIECs are good cathode materials when the volume fractions of constituent phases and porosity are carefully controlled. Such electrodes have low interfacial resistance, better binding strength, and smaller thermal mismatch with the BCG electrolyte, compared to other metal electrodes (such as Pt and Ag). Ni-BCG composite MIECs are studied as anode materials. It is found that electrodes prepared from NiO and reduced to Ni in situ is not catalytically active because of diffusion of NiO into BCG, which forms a resistive layer. Electrodes prepared from Ni metal and fired in an inert or reducing atmosphere exhibit low interfacial resistance and good compatibility with BCG electrolyte. Stability of these developed electrode materials is investigated under conditions pertinent to SOFCs.

Aeolian vibration control of overhead electrical transmission line conductors

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

Sireteanu, T.; Migdalovici, M.; Videa, E.

The paper presents a mathematical model and an analytical procedure to control the wind induced vibration of a single conductor such that the dynamic strain about the suspension clamp is kept within the imposed safety limits. The method is based on the energy balance principle which takes into account the wind energy input, the energy dissipated by the conductor self-damping properties and by the Stockbridge dampers which are frequently used for the aeolian vibration control. The damping characteristics of the Stockbridge dampers are expressed in terms of their mechanical impedance determined experimentally on a vibration exciter. The method can bemore » used to establish whether or not it is necessary to equip the conductor by Stockbridge dampers, which type of damper is more suitable for a given conductor, span length and EDS (every day stress), the necessary number of dampers as well as their optimum spacing on the conductor.« less

Rational design of mixed ionic and electronic conducting perovskite oxides for solid oxide fuel cell anode materials: A case study for doped SrTiO3

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

Suthirakun, Suwit; Xiao, Guoliang; Ammal, Salai Cheettu

2014-01-01

The effect of p- and n-type dopants on ionic and electronic conductivity of SrTiO3 based perovskites were investigated both computationally and experimentally. Specifically, we performed density functional theory (DFT) calculations of Na- and La-doped SrTiO3 and Na- and Nb-doped SrTiO3 systems. Constrained ab initio thermodynamic calculations were used to evaluate the phase stability and reducibility of doped SrTiO3 under both oxidizing and reducing synthesis conditions, as well as under anodic solid oxide fuel cell (SOFC) conditions. The density of states (DOS) of these materials was analyzed to study the effects of p- and n-doping on the electronic conductivity. Furthermore, Na-more » and La-doped SrTiO3 and Na- and Nb-doped SrTiO3 samples were experimentally prepared and the conductivity was measured to confirm our computational predictions. The experimental observations are in very good agreement with the theoretical predictions that doping n-doped SrTiO3 with small amounts of p-type dopants promotes both the ionic and electronic conductivity of the material. This doping strategy is valid independent of p- and n-doping site and permits the synthesis of perovskite based mixed ionic/electronic conductors.« less

Enhanced ionic conductivity with Li 7O 2Br 3 phase in Li 3OBr anti-perovskite solid electrolyte

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

Zhu, Jinlong; Li, Shuai; Zhang, Yi

Cubic anti-perovskites with general formula Li 3OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li 3OBr and layered Li 7O 2Br 3, by solid state reaction routes. The results indicate that with the phase fraction of Li 7O 2Br 3 increasingmore » to 44 wt. %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li 3OBr. Formation energy calculations revealed the meta-stable nature of Li 7O 2Br 3, which supports the great difficulty in producing phase-pure Li 7O 2Br 3 at ambient pressure. Here, methods of obtaining phase-pure Li 7O 2Br 3 will continue to be explored, including both high pressure and metathesis techniques.« less

Enhanced ionic conductivity with Li 7O 2Br 3 phase in Li 3OBr anti-perovskite solid electrolyte

DOE PAGES

Zhu, Jinlong; Li, Shuai; Zhang, Yi; ...

2016-09-07

Cubic anti-perovskites with general formula Li 3OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li 3OBr and layered Li 7O 2Br 3, by solid state reaction routes. The results indicate that with the phase fraction of Li 7O 2Br 3 increasingmore » to 44 wt. %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li 3OBr. Formation energy calculations revealed the meta-stable nature of Li 7O 2Br 3, which supports the great difficulty in producing phase-pure Li 7O 2Br 3 at ambient pressure. Here, methods of obtaining phase-pure Li 7O 2Br 3 will continue to be explored, including both high pressure and metathesis techniques.« less

Electrochemical performance of Li-rich oxide composite material coated with Li0.75La0.42TiO3 ionic conductor

NASA Astrophysics Data System (ADS)

Yang, Chun-Chen; Liao, Pin-Ci; Wu, Yi-Shiuan; Lue, Shingjiang Jessie

2017-03-01

Li-rich (spray-dried (SP)-Li1.2Ni0.2Mn0.60O2) composite materials were prepared via two-step ball-mill and spray dry methods by using LiOH, α-MnO2, β-Ni(OH)2 raw materials. Two raw materials of α-MnO2 nanowires and microsphere β-Ni(OH)2 were synthesized by a hydrothermal process. In addition, Li0.75La0.42TiO3 (LLTO) fast ionic conductor was coated on SP-Li1.2Ni0.2Mn0.60O2 composite via a sol-gel method. The properties of the LLTO-coated SP-Li1.2Ni0.2Mn0.60O2 composites were determined by X-ray diffraction, scanning electron microscopy, micro-Raman, XPS, and the AC impedance method. The discharge capacities of 1 wt.%-LLTO-coated SP-Li1.2Ni0.2Mn0.60O2 composites were 256, 250, 231, 200, 158, and 114 mAh g-1 at rates of 0.1, 0.2, 0.5, 1, 3, and 5C, respectively, in the voltage range 2.0-4.8 V. The 1 wt.%-LLTO-coated Li-rich oxide composite showed the discharge capacities of up to 256 mAh g-1 in the first cycle at 0.1C. After 30 cycles, the discharge capacity of 244 mAh g-1 was obtained, which showed the capacity retention of 95.4%.

Microminiature coaxial cable and methods manufacture

DOEpatents

Bongianni, Wayne L.

1986-01-01

A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 .mu.m thick and from 150 to 200 .mu.m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion.

Microminiature coaxial cable and method of manufacture

DOEpatents

Bongianni, W.L.

1989-03-28

A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 [mu]m thick and from 150 to 200 [mu]m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately, the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microspheres to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion. 2 figs.

Microminiature coaxial cable and method of manufacture

DOEpatents

Bongianni, Wayne L.

1989-01-01

A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 .mu.m thick and from 150 to 200 .mu.m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately, the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microspheres to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion.

Microminiature coaxial cable and methods of manufacture

DOEpatents

Bongianni, W.L.

1983-12-29

A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 ..mu..m thick and from 150 to 200 ..mu..m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dieleectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion.

Microminiature coaxial cable and methods manufacture

DOEpatents

Bongianni, W.L.

1986-04-08

A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 [mu]m thick and from 150 to 200 [mu]m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion. 2 figs.

Zee electrical interconnect

NASA Technical Reports Server (NTRS)

Rust, Thomas M. (Inventor); Gaddy, Edward M. (Inventor); Herriage, Michael J. (Inventor); Patterson, Robert E. (Inventor); Partin, Richard D. (Inventor)

2001-01-01

An interconnect, having some length, that reliably connects two conductors separated by the length of the interconnect when the connection is made but in which one length if unstressed would change relative to the other in operation. The interconnect comprises a base element an intermediate element and a top element. Each element is rectangular and formed of a conducting material and has opposed ends. The elements are arranged in a generally Z-shape with the base element having one end adapted to be connected to one conductor. The top element has one end adapted to be connected to another conductor and the intermediate element has its ends disposed against the other end of the base and the top element. Brazes mechanically and electrically interconnect the intermediate element to the base and the top elements proximate the corresponding ends of the elements. When the respective ends of the base and the top elements are connected to the conductors, an electrical connection is formed therebetween, and when the conductors are relatively moved or the interconnect elements change length the elements accommodate the changes and the associated compression and tension forces in such a way that the interconnect does not mechanically fatigue.

Fatigue tests of YBCO coated conductors

NASA Astrophysics Data System (ADS)

Bamba, S.; Tanaka, Y.; Ando, T.; Ueda, H.; Ishiyama, A.; Yamada, Y.; Shiohara, Y.

2008-02-01

In this paper, we report the fatigue characteristics of IBAD/PLD YBCO coated conductors. A YBCO coated conductor used in the superconducting coil of a SMES system is repeatedly subjected to mechanical tensile or compressive strain due to the Lorentz force during electrical charging or discharging. The superconducting characteristic of this conductor may deteriorate because of this cyclic strain. Therefore, it is necessary to investigate the effect of cyclic strain on the superconducting characteristics of YBCO coated conductors that have a laminated structure. We developed an experimental apparatus with a U-shaped sample holder in order to apply cyclic strain to the sample tape. This apparatus was used to perform the fatigue tests on YBCO coated conductors in liquid nitrogen in the absence of an external magnetic field. The strain cycles with the maximum strain epsilonmax (zero external strain → epsilonmax → zero external strain) were applied and repeated up to 5000 times, and the Ic measurements were performed at epsilonmax. Therefore, the application of cyclic strain with epsilonmax ranging from 0.3% to 0.5% did not result in any significant deterioration of the superconducting characteristics of the conductor.

Making the case for high temperature low sag (htls) overhead transmission line conductors

NASA Astrophysics Data System (ADS)

Banerjee, Koustubh

The future grid will face challenges to meet an increased power demand by the consumers. Various solutions were studied to address this issue. One alternative to realize increased power flow in the grid is to use High Temperature Low Sag (HTLS) since it fulfills essential criteria of less sag and good material performance with temperature. HTLS conductors like Aluminum Conductor Composite Reinforced (ACCR) and Aluminum Conductor Carbon Composite (ACCC) are expected to face high operating temperatures of 150-200 degree Celsius in order to achieve the desired increased power flow. Therefore, it is imperative to characterize the material performance of these conductors with temperature. The work presented in this thesis addresses the characterization of carbon composite core based and metal matrix core based HTLS conductors. The thesis focuses on the study of variation of tensile strength of the carbon composite core with temperature and the level of temperature rise of the HTLS conductors due to fault currents cleared by backup protection. In this thesis, Dynamic Mechanical Analysis (DMA) was used to quantify the loss in storage modulus of carbon composite cores with temperature. It has been previously shown in literature that storage modulus is correlated to the tensile strength of the composite. Current temperature relationships of HTLS conductors were determined using the IEEE 738-2006 standard. Temperature rise of these conductors due to fault currents were also simulated. All simulations were performed using Microsoft Visual C++ suite. Tensile testing of metal matrix core was also performed. Results of DMA on carbon composite cores show that the storage modulus, hence tensile strength, decreases rapidly in the temperature range of intended use. DMA on composite cores subjected to heat treatment were conducted to investigate any changes in the variation of storage modulus curves. The experiments also indicates that carbon composites cores subjected to temperatures at or above 250 degree Celsius can cause permanent loss of mechanical properties including tensile strength. The fault current temperature analysis of carbon composite based conductors reveal that fault currents eventually cleared by backup protection in the event of primary protection failure can cause damage to fiber matrix interface.

Mechanical design of thin-film diamond crystal mounting apparatus with optimized thermal contact and crystal strain for coherence preservation x-ray optics

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

Shu, Deming; Shvydko, Yury; Stoupin, Stanislav

A method and mechanical design for a thin-film diamond crystal mounting apparatus for coherence preservation x-ray optics with optimized thermal contact and minimized crystal strain are provided. The novel thin-film diamond crystal mounting apparatus mounts a thin-film diamond crystal supported by a thick chemical vapor deposition (CVD) diamond film spacer with a thickness slightly thicker than the thin-film diamond crystal, and two groups of thin film thermal conductors, such as thin CVD diamond film thermal conductor groups separated by the thick CVD diamond spacer. The two groups of thin CVD film thermal conductors provide thermal conducting interface media with themore » thin-film diamond crystal. A piezoelectric actuator is integrated into a flexural clamping mechanism generating clamping force from zero to an optimal level.« less

High current capacity electrical connector

DOEpatents

Bettis, Edward S.; Watts, Harry L.

1976-01-13

An electrical connector is provided for coupling high current capacity electrical conductors such as copper busses or the like. The connector is arranged in a "sandwiched" configuration in which a conductor plate contacts the busses along major surfaces thereof clamped between two stainless steel backing plates. The conductor plate is provided with a plurality of contact buttons affixed therein in a spaced array such that the caps of the buttons extend above the conductor plate surface to contact the busses. When clamping bolts provided through openings in the sandwiched arrangement are tightened, Belleville springs provided under the rim of each button cap are compressed and resiliently force the caps into contact with the busses' contacting surfaces to maintain a predetermined electrical contact area provided by the button cap tops. The contact area does not change with changing thermal or mechanical stresses applied to the coupled conductors.

Ultra-stretchable conductors based on buckled super-aligned carbon nanotube films.

PubMed

Yu, Yang; Luo, Shu; Sun, Li; Wu, Yang; Jiang, Kaili; Li, Qunqing; Wang, Jiaping; Fan, Shoushan

2015-06-14

Ultra-stretchable conductors are fabricated by coating super-aligned carbon nanotube (SACNT) films on pre-strained polydimethylsiloxane (PDMS) substrates and forming buckled SACNT structures on PDMS after release of the pre-strain. The parallel SACNT/PDMS conductors demonstrate excellent stability with normalized resistance changes of only 4.1% under an applied strain as high as 200%. The SACNT/PDMS conductors prepared with cross-stacked SACNT films show even lower resistance variation. The parallel SACNT/PDMS conductors exhibit high durability with a resistance increase of less than 5% after 10,000 cycles at 150% strain. In situ microscopic observations demonstrate that the buckled SACNT structures are straightened during the stretching process with reversible morphology evolution and thus the continuous SACNT conductive network can be protected from fracture. Due to the excellent electrical and mechanical properties of SACNT films and the formation of the buckled structure, SACNT/PDMS films exhibit high stretchability and durability, possessing great potential for use as ultra-stretchable conductors for wearable electronics, sensors, and energy storage devices.

Method of doping a semiconductor

DOEpatents

Yang, Chiang Y.; Rapp, Robert A.

1983-01-01

A method for doping semiconductor material. An interface is established between a solid electrolyte and a semiconductor to be doped. The electrolyte is chosen to be an ionic conductor of the selected impurity and the semiconductor material and electrolyte are jointly chosen so that any compound formed from the impurity and the semiconductor will have a free energy no lower than the electrolyte. A potential is then established across the interface so as to allow the impurity ions to diffuse into the semiconductor. In one embodiment the semiconductor and electrolyte may be heated so as to increase the diffusion coefficient.

29 CFR 1910.254 - Arc welding and cutting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 80 volts. (c) Installation of arc welding equipment—(1) General. Installation including power supply... mechanically strong and electrically adequate for the required current. (3) Supply connections and conductors...-carrying capacity of the supply conductors shall be not less than the rated primary current of the welding...

Piezoelectricity and rotostriction through polar and non-polar coupled instabilities in bismuth-based piezoceramics

PubMed Central

Acosta, Matias; Schmitt, Ljubomira A.; Cazorla, Claudio; Studer, Andrew; Zintler, Alexander; Glaum, Julia; Kleebe, Hans-Joachim; Donner, Wolfgang; Hoffman, Mark; Rödel, Jürgen; Hinterstein, Manuel

2016-01-01

Coupling of order parameters provides a means to tune functionality in advanced materials including multiferroics, superconductors, and ionic conductors. We demonstrate that the response of a frustrated ferroelectric state leads to coupling between order parameters under electric field depending on grain orientation. The strain of grains oriented along a specific crystallographic direction, 〈h00〉, is caused by converse piezoelectricity originating from a ferrodistortive tetragonal phase. For 〈hhh〉 oriented grains, the strain results from converse piezoelectricity and rotostriction, as indicated by an antiferrodistortive instability that promotes octahedral tilting in a rhombohedral phase. Both strain mechanisms combined lead to a colossal local strain of (2.4 ± 0.1) % and indicate coupling between oxygen octahedral tilting and polarization, here termed “rotopolarization”. These findings were confirmed with electromechanical experiments, in situ neutron diffraction, and in situ transmission electron microscopy in 0.75Bi1/2Na1/2TiO3-0.25SrTiO3. This work demonstrates that polar and non-polar instabilities can cooperate to provide colossal functional responses. PMID:27364037

Ion-conduction mechanisms in NaSICON-type membranes for energy storage and utilization

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

McDaniel, Anthony H.; Ihlefeld, Jon F.; Bartelt, Norman Charles

2015-10-01

Next generation metal-ion conducting membranes are key to developing energy storage and utilization technologies like batteries and fuel ce lls. Sodium super-ionic conductors (aka NaSICON) are a class of compounds with AM 1 M 2 (PO 4 ) 3 stoichiometry where the choice of "A" and "M" cation varies widely. This report, which de scribes substitutional derivatives of NZP (NaZr 2 P 3 O 12 ), summarizes the accomplishments of a Laboratory D irected Research and Development (LDRD) project to analyze transport mec hanisms using a combination of in situ studies of structure, composition, and bonding, com bined with firstmore » principles theory and modeling. We developed an experimental platform and applied methods, such as synchrotron- based X-ray spectroscopies, to probe the electronic structure of compositionally well-controlled NaSICON films while in operation ( i.e ., conducting Na ions exposed to oxygen or water va por atmospheres). First principles theory and modeling were used to interpret the experimental observations and develop an enhanced understanding of atomistic processes that give rise to, and affect, ion conduction.« less

Synthesis and characterization of a NaSICON series with general formula Na 2.8Zr 2-ySi 1.8-4yP 1.2+4yO 12 (0⩽ y⩽0.45)

NASA Astrophysics Data System (ADS)

Essoumhi, A.; Favotto, C.; Mansori, M.; Satre, P.

2004-12-01

In this work, we present the synthesis and the characterization of ionic conducting ceramics of NaSICON-type (Natrium super ionic conductor). The properties of this ceramic make it suitable for use in electrochemical devices. These solid electrolytes can be used as sensors for application in the manufacturing of potentiometric gas sensors, for the detection of pollutant emissions and for environment control. The family of NaSICON that we studied has as a general formula Na 2.8Zr 2-ySi 1.8-4yP 1.2+4yO 12 with 0⩽ y⩽0.45. The various compositions were synthesized by produced using the sol-gel method. The electric properties of these compositions were carried out by impedance spectroscopy. The results highlight the good conductivity of the Na 2.8Zr 1.775Si 0.9P 2.1O 12 composition.

Hydrogen bond basicity of ionic liquids and molar entropy of hydration of salts as major descriptors in the formation of aqueous biphasic systems.

PubMed

Passos, Helena; Dinis, Teresa B V; Cláudio, Ana Filipa M; Freire, Mara G; Coutinho, João A P

2018-05-23

Aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and conventional salts have been largely investigated and successfully used in separation processes, for which the determination of the corresponding ternary phase diagrams is a prerequisite. However, due the large number of ILs that can be prepared and their high structural versatility, it is impossible to experimentally cover and characterize all possible combinations of ILs and salts that may form ABS. The development of tools for the prediction and design of IL-based ABS is thus a crucial requirement. Based on a large compilation of experimental data, a correlation describing the formation of IL-based ABS is shown here, based on the hydrogen-bonding interaction energies of ILs (EHB) obtained by the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) and the molar entropy of hydration of the salt ions. The ability of the proposed model to predict the formation of novel IL-based ABS is further ascertained.

Efficient Transport Networks in a Dual Electron/Lithium-Conducting Polymeric Composite for Electrochemical Applications.

PubMed

McDonald, Michael B; Hammond, Paula T

2018-05-09

In this work, an all-functional polymer material composed of the electrically conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) (PEDOT:PSS) and lithium-conducting poly(ethylene oxide) (PEO) was developed to form a dual conductor for three-dimensional electrodes in electrochemical applications. The composite exhibits enhanced ionic conductivity (∼10 -4 S cm -1 ) and, counterintuitively, electronic conductivity (∼45 S cm -1 ) with increasing PEO proportion, optimal at a monomer ratio of 20:1 PEO:PEDOT. Microscopy reveals a unique morphology, where PSS interacts favorably with PEO, destabilizing PEDOT to associate into highly branched, interconnected networks that allow for more efficient electronic transport despite relatively low concentrations. Thermal and X-ray techniques affirm that the PSS-PEO domain suppresses crystallinity, explaining the high ionic conductivity. Electrochemical experiments in lithium cell environments indicate stability as a function of cycling and improved overpotential due to dual transport characteristics despite known issues with both individual components.

Design and synthesis of the superionic conductor Na10SnP2S12

PubMed Central

Richards, William D.; Tsujimura, Tomoyuki; Miara, Lincoln J.; Wang, Yan; Kim, Jae Chul; Ong, Shyue Ping; Uechi, Ichiro; Suzuki, Naoki; Ceder, Gerbrand

2016-01-01

Sodium-ion batteries are emerging as candidates for large-scale energy storage due to their low cost and the wide variety of cathode materials available. As battery size and adoption in critical applications increases, safety concerns are resurfacing due to the inherent flammability of organic electrolytes currently in use in both lithium and sodium battery chemistries. Development of solid-state batteries with ionic electrolytes eliminates this concern, while also allowing novel device architectures and potentially improving cycle life. Here we report the computation-assisted discovery and synthesis of a high-performance solid-state electrolyte material: Na10SnP2S12, with room temperature ionic conductivity of 0.4 mS cm−1 rivalling the conductivity of the best sodium sulfide solid electrolytes to date. We also computationally investigate the variants of this compound where tin is substituted by germanium or silicon and find that the latter may achieve even higher conductivity. PMID:26984102

Local Dynamics of Acid- and Ion-containing Copolymer Melts

NASA Astrophysics Data System (ADS)

Winey, Karen; Middleton, Robert; Tarver, Jacob; Tyagi, Madhusudan; Soles, Christopher; Frischknecht, Amalie

Interest in acid- and ion-containing polymers arises in part from applications as single-ion conductors for selectively transporting a counter ion for battery applications. Structurally, the low dielectric constant of organic polymers and strong ionic interactions leads to ionic aggregation. Here the polymer backbone motion was investigated through quasi-elastic neutron scattering measurements (QENS) and compared with fully atomistic molecular dynamic simulations of precise poly(ethylene-acrylic acid) copolymers and their ionomers (pxAA-y%Li). The effect of carbon spacer length (x =9, 15, 21) between the acid groups and the degree of neutralization (y) with Li on PE backbone dynamics were considered. Systematic slowing in chain dynamics were observed with increasing neutralization where polymer dynamics appear constrained due to anchoring effects. Simulations provide complementary viewpoints indicating a gradient in chain dynamics as a distance away from acid groups. These results indicate that the addition of pendant acid groups inhibit typical PE backbone motion and the neutralized forms strongly suppress the fraction of mobile PE chain.

Probing nanoscale ion dynamics in ultrathin films of polymerized ionic liquids by broadband dielectric spectroscopy

NASA Astrophysics Data System (ADS)

Sangoro, Joshua; Heres, Maximilian; Cosby, Tyler

Continuous progress in energy storage and conversion technologies necessitates novel experimental approaches that can provide fundamental insights regarding the impact of reduced dimensions on the functional properties of materials. In this talk, a nondestructive experimental approach to probe nanoscale ion dynamics in ultrathin films of polymerized ionic liquids over a broad frequency range spanning over six orders of magnitude by broadband dielectric spectroscopy will be presented. The approach involves using an electrode configuration with lithographically patterned silica nanostructures, which allow for an air gap between the confined ion conductor and one of the electrodes. It is observed that the characteristic ion dynamics rates significantly slow down with decreasing film thicknesses above the calorimetric glass transition of the bulk polymer. However, the mean rates remain bulk-like at lower temperatures. These results highlight the increasing influence of the polymer/substrate interactions with decreasing film thickness on ion dynamics. The authors gratefully acknowledge the National Science Foundation for financial support through the Polymers Program award DMR-1508394.

One-volt-driven superfast polymer actuators based on single-ion conductors

PubMed Central

Kim, Onnuri; Kim, Hoon; Choi, U. Hyeok; Park, Moon Jeong

2016-01-01

The key challenges in the advancement of actuator technologies related to artificial muscles include fast-response time, low operation voltages and durability. Although several researchers have tackled these challenges over the last few decades, no breakthrough has been made. Here we describe a platform for the development of soft actuators that moves a few millimetres under 1 V in air, with a superfast response time of tens of milliseconds. An essential component of this actuator is the single-ion-conducting polymers that contain well-defined ionic domains through the introduction of zwitterions; this achieved an exceptionally high dielectric constant of 76 and a 300-fold enhancement in ionic conductivity. Moreover, the actuator demonstrated long-term durability, with negligible changes in the actuator stroke over 20,000 cycles in air. Owing to its low-power consumption (only 4 mW), we believe that this actuator could pave the way for cutting-edge biomimetic technologies in the future. PMID:27857067

Bayesian-Driven First-Principles Calculations for Accelerating Exploration of Fast Ion Conductors for Rechargeable Battery Application.

PubMed

Jalem, Randy; Kanamori, Kenta; Takeuchi, Ichiro; Nakayama, Masanobu; Yamasaki, Hisatsugu; Saito, Toshiya

2018-04-11

Safe and robust batteries are urgently requested today for power sources of electric vehicles. Thus, a growing interest has been noted for fabricating those with solid electrolytes. Materials search by density functional theory (DFT) methods offers great promise for finding new solid electrolytes but the evaluation is known to be computationally expensive, particularly on ion migration property. In this work, we proposed a Bayesian-optimization-driven DFT-based approach to efficiently screen for compounds with low ion migration energies ([Formula: see text]. We demonstrated this on 318 tavorite-type Li- and Na-containing compounds. We found that the scheme only requires ~30% of the total DFT-[Formula: see text] evaluations on the average to recover the optimal compound ~90% of the time. Its recovery performance for desired compounds in the tavorite search space is ~2× more than random search (i.e., for [Formula: see text] < 0.3 eV). Our approach offers a promising way for addressing computational bottlenecks in large-scale material screening for fast ionic conductors.

Synthesis and structure of novel lithium-ion conductor Li7Ge3PS12

NASA Astrophysics Data System (ADS)

Inoue, Yuki; Suzuki, Kota; Matsui, Naoki; Hirayama, Masaaki; Kanno, Ryoji

2017-02-01

The novel lithium-ion conductor Li7Ge3PS12 was synthesized by slow cooling from the ternary Li2S-GeS2-P2S5 system, and was shown to exhibit a cubic argyrodite-type structure. The phase composition was determined by varying the ratio of starting materials; the observed monophasic properties were close to those for the Li7Ge3PS12 composition. The lattice parameter (a =9.80192(3) Å) of Li7Ge3PS12 was slightly smaller than that of Li7PS6 (a =9.993 Å), indicating that substitution of a Li cation by the smaller Ge cation contracted the cubic lattice. In addition, the novel structure consisted of a framework composed of four isolated (Ge/P)S4 tetrahedra. Li+ ions occupied tetrahedral sites within the framework, forming a three-dimensional conduction pathway. Finally, Li7Ge3PS12 exhibited a high ionic conductivity of 1.1×10-4 S cm-1 at 25 °C and an activation energy of 25 kJ mol-1.

A lithium superionic conductor.

PubMed

Kamaya, Noriaki; Homma, Kenji; Yamakawa, Yuichiro; Hirayama, Masaaki; Kanno, Ryoji; Yonemura, Masao; Kamiyama, Takashi; Kato, Yuki; Hama, Shigenori; Kawamoto, Koji; Mitsui, Akio

2011-07-31

Batteries are a key technology in modern society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Electrochemical devices with high energy and power densities can currently be powered only by batteries with organic liquid electrolytes. However, such batteries require relatively stringent safety precautions, making large-scale systems very complicated and expensive. The application of solid electrolytes is currently limited because they attain practically useful conductivities (10(-2) S cm(-1)) only at 50-80 °C, which is one order of magnitude lower than those of organic liquid electrolytes. Here, we report a lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure. It exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature. This represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes. This new solid-state battery electrolyte has many advantages in terms of device fabrication (facile shaping, patterning and integration), stability (non-volatile), safety (non-explosive) and excellent electrochemical properties (high conductivity and wide potential window).

Metallic hot wire anemometer. [for high speed wind tunnel tests

NASA Technical Reports Server (NTRS)

Lemos, F. R. (Inventor)

1977-01-01

A hot wire anemometer is described which has a body formed of heat resistant metal such as an alloy high in nickel content which supports a probe wire disposed in a V groove in the body. The V groove contains a high temperature ceramic adhesive that partially encompasses the downstream side of the probe wire. Mechanical and electrical connection to the probe wire is achieved through conductive support rods that are constructed of the same high temperature metal, insulation between the body and the conductor rods being provided by a coating of an oxide of the same material which coating is formed in situ. The oxide coating insulates the conductor rods from the body, mechanically fixes the conductors within the body, and maintains its integrity at elevated temperatures.

Toward practical all-solid-state lithium-ion batteries with high energy density and safety: Comparative study for electrodes fabricated by dry- and slurry-mixing processes

NASA Astrophysics Data System (ADS)

Nam, Young Jin; Oh, Dae Yang; Jung, Sung Hoo; Jung, Yoon Seok

2018-01-01

Owing to their potential for greater safety, higher energy density, and scalable fabrication, bulk-type all-solid-state lithium-ion batteries (ASLBs) employing deformable sulfide superionic conductors are considered highly promising for applications in battery electric vehicles. While fabrication of sheet-type electrodes is imperative from the practical point of view, reports on relevant research are scarce. This might be attributable to issues that complicate the slurry-based fabrication process and/or issues with ionic contacts and percolation. In this work, we systematically investigate the electrochemical performance of conventional dry-mixed electrodes and wet-slurry fabricated electrodes for ASLBs, by varying the different fractions of solid electrolytes and the mass loading. This information calls for a need to develop well-designed electrodes with better ionic contacts and to improve the ionic conductivity of solid electrolytes. As a scalable proof-of-concept to achieve better ionic contacts, a premixing process for active materials and solid electrolytes is demonstrated to significantly improve electrochemical performance. Pouch-type 80 × 60 mm2 all-solid-state LiNi0·6Co0·2Mn0·2O2/graphite full-cells fabricated by the slurry process show high cell-based energy density (184 W h kg-1 and 432 W h L-1). For the first time, their excellent safety is also demonstrated by simple tests (cutting with scissors and heating at 110 °C).

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

PubMed

Hirota, Yuichiro; Maeda, Yohei; Yamamoto, Yusuke; Miyamoto, Manabu; Nishiyama, Norikazu

2017-08-03

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H₂/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H₂ (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

Monolithic Solid Oxide Fuel Cell development

NASA Technical Reports Server (NTRS)

Myles, K. M.; Mcpheeters, C. C.

1989-01-01

The Monolithic Solid Oxide Fuel Cell (MSOFC) is an oxide-ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/L, at fuel efficienceis over 50 percent, because of small cell size and low resistive losses in the materials. The MSOFC operates in the range of 700 to 1000 C, at which temperatures rapid reform of hydrocarbon fuels is expected within the nickel-YSZ fuel channels. Tape casting and hot roll calendering are used to fabricate the MSOFC structure. The performance of the MSOFC has improved significantly during the course of development. The limitation of this system, based on materials resistance alone without interfacial resistances, is 0.093 ohm-sq cm area-specific resistance (ASR). The current typical performance of MSOFC single cells is characterized by ASRs of about 0.4 to 0.5 ohm-sq cm. With further development the ASR is expected to be reduced below 0.2 ohm-sq cm, which will result in power levels greater than 1.4 W/sq cm. The feasibility of the MSOFC concept was proven, and the performance was dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials were minimized. As a result of good matching of these properties, the MSOFC structure was successfully fabricated with few defects, and the system shows excellent promise for development into a practical power source.

Improved electrochemical properties of LiFe0.5Mn0.5PO4/C composite materials via a surface coating process

NASA Astrophysics Data System (ADS)

Yang, Chun-Chen; Hung, Yen-Wei; Lue, Shingjiang Jessie

2016-09-01

In this work, a LiFe0.5Mn0.5PO4/C (LFMP/C) material was prepared by a simple solid-state ball-mill method by using LiH2PO4, γ-MnO2, and hollow α-Fe2O3 nano-sized materials. Both γ-MnO2 and hollow α-Fe2O3 were synthesized by a hydrothermal process. LFMP/C composites coated with different amounts (1-3wt%) of Li4Ti5O12 (LTO) were synthesized by a sol-gel method. Their typical properties are studied using X-ray diffraction, micro-Raman spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, the AC impedance method, and the galvanostatic charge-discharge method. The results revealed that a 1 wt%-LTO-coated LFMP/C composite shows the highest performance among all LFMP/C composite samples. The long-term cycling performance of the LFMP/C composite improves considerably when the LTO ionic conductor is applied on it. Moreover, the 1 wt%-LTO-coated LFMP/C composite, which has the lowest fading rate, maintains high cycling stability at 1 C (141 mAh g-1) and 10 C (133 mAh g-1) at 55 °C after 100 cycles; by contrast, a bare LFMP/C sample, which demonstrates the highest fading rate, exhibits an unfavorable life cycle, and its discharge capacity decreases rapidly. The ionic conductor coating thus improves the high-temperature performance of LFMP/C composites. A LFMP/C-KS6/SiO2 full cell is assembled and tested.

VR-SCOSMO: A smooth conductor-like screening model with charge-dependent radii for modeling chemical reactions.

PubMed

Kuechler, Erich R; Giese, Timothy J; York, Darrin M

2016-04-28

To better represent the solvation effects observed along reaction pathways, and of ionic species in general, a charge-dependent variable-radii smooth conductor-like screening model (VR-SCOSMO) is developed. This model is implemented and parameterized with a third order density-functional tight binding quantum model, DFTB3/3OB-OPhyd, a quantum method which was developed for organic and biological compounds, utilizing a specific parameterization for phosphate hydrolysis reactions. Unlike most other applications with the DFTB3/3OB model, an auxiliary set of atomic multipoles is constructed from the underlying DFTB3 density matrix which is used to interact the solute with the solvent response surface. The resulting method is variational, produces smooth energies, and has analytic gradients. As a baseline, a conventional SCOSMO model with fixed radii is also parameterized. The SCOSMO and VR-SCOSMO models shown have comparable accuracy in reproducing neutral-molecule absolute solvation free energies; however, the VR-SCOSMO model is shown to reduce the mean unsigned errors (MUEs) of ionic compounds by half (about 2-3 kcal/mol). The VR-SCOSMO model presents similar accuracy as a charge-dependent Poisson-Boltzmann model introduced by Hou et al. [J. Chem. Theory Comput. 6, 2303 (2010)]. VR-SCOSMO is then used to examine the hydrolysis of trimethylphosphate and seven other phosphoryl transesterification reactions with different leaving groups. Two-dimensional energy landscapes are constructed for these reactions and calculated barriers are compared to those obtained from ab initio polarizable continuum calculations and experiment. Results of the VR-SCOSMO model are in good agreement in both cases, capturing the rate-limiting reaction barrier and the nature of the transition state.

Research on the Test of Transmission Line Galloping

NASA Astrophysics Data System (ADS)

Zhang, Lichun; Li, Qing; lv, Zhongbin; Ji, Kunpeng; Liu, Bin

2018-03-01

The load of iced transmission line and the load generated by galloping after the conductor are covered by ice all may cause severe circuit faults, such as tripping, conductor breaking, armor clamp damage and even tower collapse, thus severely threatening running safety of power system. The generation and development processes of galloping of power transmission line is very complicated, and numerous factors may influence the galloping excitation, such as environmental factors, terrain factors and structural parameters of power transmission line; in which, the ice covering of conductor is one of necessary factors causing galloping. Therefore, researches on ice covering increasing test of different types of conductors under different meteorological conditions have been conducted in large-sized multi-functional phytotron, thus obtaining the relation curve of ice covering increasing of conductor along with time under different conditions, and analyzing factors influencing increasing of ice covering. The research result shows that under the same ice covering conditions, the increasing of ice covering of conductor with small diameter is relatively rapid; both environmental temperature and wind speed have obvious influence on increasing of ice covering of conductor, and the environmental temperature will decide the type of ice covering of conductor surface. Meanwhile, after wind tunnel tests targeting conductors with different ice covering shapes, pneumatic stability loss characteristics of conductors with different ice shapes have been obtained. Research results have important scientific reference value for revealing the mechanism of galloping of iced power transmission line, and have relatively high engineering practicability value for promoting realization of early warning system for galloping of iced power transmission line.

Experimental results of 40-kA Nb[sub 3]Al cable-in-conduit conductor for fusion machines

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

Takahashi, Y.; Sugimoto, M.; Isono, T.

1994-07-01

A 40-kA Nb[sub 3]Al cable-in-conduit conductor has been developed for the toroidal field coils of fusion reactors, because Nb[sub 3]Al has excellent mechanical performance. This conductor consists of 405 copper-stabilized multifilamentary strands inserted into a CuNi case circular conduit. The Nb[sub 3]Al strands are fabricated by the Jelly-roll process with a diameter of 1.22 mm. This conductor could be operated up to a current of 46 kA at an external field of 11.2 T. Accordingly, Nb[sub 3]Al promises to soon become a useful superconductor for large-scale high-field applications, such as fusion machines.

Thermal management system and method for a solid-state energy storing device

DOEpatents

Rouillard, Roger; Domroese, Michael K.; Gauthier, Michel; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Ranger, Michel; Rouillard, Jean; Shiota, Toshimi; St-Germain, Philippe; Sudano, Anthony; Trice, Jennifer L.; Turgeon, Thomas A.

2000-01-01

An improved electrochemical energy storing device includes a number of thin-film electrochemical cells which are maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of each electrochemical cell, conducts current into and out of the electrochemical cells and also conducts thermal energy between the electrochemical cells and thermally conductive material disposed on a wall structure adjacent the conductors. The wall structure includes electrically resistive material, such as an anodized coating or a thin film of plastic. The thermal conductors are fabricated to include a spring mechanism which expands and contacts to maintain mechanical contact between the electrochemical cells and the thermally conductive material in the presence of relative movement between the electrochemical cells and the wall structure. An active cooling apparatus may be employed external to a hermetically sealed housing containing the electrochemical cells to enhance the transfer of thermal energy into and out of the electrochemical cells. An integrated interconnect board may be disposed within the housing onto which a number of electrical and electro-mechanical components are mounted. Heat generated by the components is conducted from the interconnect board to the housing using the thermal conductors.

An open circuit voltage equation enabling separation of cathode and anode polarization resistances of ceria electrolyte based solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Zhang, Yanxiang; Chen, Yu; Yan, Mufu

2017-07-01

The open circuit voltage (OCV) of solid oxide fuel cells is generally overestimated by the Nernst equation and the Wagner equation, due to the polarization losses at electrodes. Considering both the electronic conduction of electrolyte and the electrode polarization losses, we express the OCV as an implicit function of the characteristic oxygen pressure of electrolyte (p* [atm], at which the electronic and ionic conductivities are the same), and the relative polarization resistance of electrodes (rc = Rc/Ri and ra = Ra/Ri, where Ri/c/a [Ωcm2] denotes the ionic resistance of electrolyte, and the polarization resistances of cathode and anode, respectively). This equation approaches to the Wagner equation when the electrodes are highly active (rc and ra → 0), and approaches to the Nernst equation when the electrolyte is a purely ionic conductor (p* → 0). For the fuel cells whose OCV is well below the prediction of the Wagner equation, for example with thin doped ceria electrolyte, it is demonstrated that the combination of OCV and impedance spectroscopy measurements allows the determination of p*, Rc and Ra. This equation can serve as a simple yet powerful tool to study the internal losses in the cell under open circuit condition.

Lithium ion dynamics in Li2S+GeS2+GeO2 glasses studied using (7)Li NMR field-cycling relaxometry and line-shape analysis.

PubMed

Gabriel, Jan; Petrov, Oleg V; Kim, Youngsik; Martin, Steve W; Vogel, Michael

2015-09-01

We use (7)Li NMR to study the ionic jump motion in ternary 0.5Li2S+0.5[(1-x)GeS2+xGeO2] glassy lithium ion conductors. Exploring the "mixed glass former effect" in this system led to the assumption of a homogeneous and random variation of diffusion barriers in this system. We exploit that combining traditional line-shape analysis with novel field-cycling relaxometry, it is possible to measure the spectral density of the ionic jump motion in broad frequency and temperature ranges and, thus, to determine the distribution of activation energies. Two models are employed to parameterize the (7)Li NMR data, namely, the multi-exponential autocorrelation function model and the power-law waiting times model. Careful evaluation of both of these models indicates a broadly inhomogeneous energy landscape for both the single (x=0.0) and the mixed (x=0.1) network former glasses. The multi-exponential autocorrelation function model can be well described by a Gaussian distribution of activation barriers. Applicability of the methods used and their sensitivity to microscopic details of ionic motion are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Key parameters governing the densification of cubic-Li7La3Zr2O12 Li+ conductors

NASA Astrophysics Data System (ADS)

Yi, Eongyu; Wang, Weimin; Kieffer, John; Laine, Richard M.

2017-06-01

Cubic-Li7La3Zr2O12 (LLZO) is regarded as one of the most promising solid electrolytes for the construction of inherently safe, next generation all-solid-state Li batteries. Unfortunately, sintering these materials to full density with controlled grain sizes, mechanical and electrochemical properties relies on energy and equipment intensive processes. In this work, we elucidate key parameters dictating LLZO densification by tracing the compositional and structural changes during processing calcined and ball-milled Al3+ doped LLZO powders. We find that the powders undergo ion (Li+/H+) exchange during room temperature processing, such that on heating, the protonated LLZO lattice collapses and crystallizes to its constituent oxides, leading to reaction driven densification at < 1000 °C, prior to sintering of LLZO grains at higher temperatures. It is shown that small particle sizes and protonation cannot be decoupled, and actually aid densification. We conclude that using fully decomposed nanoparticle mixtures, as obtained by liquid-feed flame spray pyrolysis, provides an ideal approach to use high surface and reaction energy to drive densification, resulting in pressureless sintering of Ga3+ doped LLZO thin films (25 μm) at 1130 °C/0.3 h to ideal microstructures (95 ± 1% density, 1.2 ± 0.2 μm average grain size) normally accessible only by pressure-assisted sintering. Such films offer both high ionic conductivity (1.3 ± 0.1 mS cm-1) and record low ionic area specific resistance (2 Ω cm2).

Li diffusion and the effect of local structure on Li mobility in Li2O-SiO2 glasses.

PubMed

Bauer, Ute; Welsch, Anna-Maria; Behrens, Harald; Rahn, Johanna; Schmidt, Harald; Horn, Ingo

2013-12-05

Aimed to improve the understanding of lithium migration mechanisms in ion conductors, this study focuses on Li dynamics in binary Li silicate glasses. Isotope exchange experiments and conductivity measurements were carried out to determine self-diffusion coefficients and activation energies for Li migration in Li2Si3O7 and Li2Si6O13 glasses. Samples of identical composition but different isotope content were combined for diffusion experiments in couples or triples. Diffusion profiles developed between 511 and 664 K were analyzed by femtosecond laser ablation combined with multiple collector inductively coupled plasma mass spectrometry (fs LA-MC-ICP-MS) and secondary ion mass spectrometry (SIMS). Analyses of diffusion profiles and comparison of diffusion data reveal that the isotope effect of lithium diffusion in silicate glasses is rather small, consistent with classical diffusion behavior. Ionic conductivity of glasses was measured between 312 and 675 K. The experimentally obtained self-diffusion coefficient, D(IE), and ionic diffusion coefficient, D(σ), derived from specific DC conductivity provided information about correlation effects during Li diffusion. The D(IE)/D(σ) is higher for the trisilicate (0.27 ± 0.05) than that for the hexasilicate (0.17 ± 0.02), implying that increasing silica content reduces the efficiency of Li jumps in terms of long-range movement. This trend can be rationalized by structural concepts based on nuclear magnetic resonance (NMR) and Raman spectroscopy as well as molecular dynamic simulations, that is, lithium is percolating in low-dimensional, alkali-rich regions separated by a silica-rich matrix.

Structural, Chemical, and Dynamical Frustration: Origins of Superionic Conductivity in closo -Borate Solid Electrolytes

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

Kweon, Kyoung E.; Varley, Joel B.; Shea, Patrick

Li 2B 12H 12, Na 2B 12H 12, and their closo-borate relatives exhibit unusually high ionic conductivity, making them attractive as a new class of candidate electrolytes in solid-state Li- and Na-ion batteries. However, further optimization of these materials requires a deeper understanding of the fundamental mechanisms underlying ultrafast ion conduction. To this end, we use ab initio molecular dynamics simulations and density-functional calculations to explore the motivations for cation diffusion. We find that superionic behavior in Li 2B 12H 12 and Na 2B 12H 12 results from a combination of key structural, chemical, and dynamical factors that introduce intrinsicmore » frustration and disorder. A statistical metric is used to show that the structures exhibit a high density of accessible interstitial sites and site types, which correlates with the flatness of the energy landscape and the observed cation mobility. Furthermore, cations are found to dock to specific anion sites, leading to a competition between the geometric symmetry of the anion and the symmetry of the lattice itself, which can facilitate cation hopping. Finally, facile anion reorientations and other low-frequency thermal vibrations lead to fluctuations in the local potential that enhance cation mobility by creating a local driving force for hopping. In conclusion, we discuss the relevance of each factor for developing new ionic conductivity descriptors that can be used for discovery and optimization of closo-borate solid electrolytes, as well as superionic conductors more generally.« less

Structural, Chemical, and Dynamical Frustration: Origins of Superionic Conductivity in closo -Borate Solid Electrolytes

DOE PAGES

Kweon, Kyoung E.; Varley, Joel B.; Shea, Patrick; ...

2017-10-11

Li 2B 12H 12, Na 2B 12H 12, and their closo-borate relatives exhibit unusually high ionic conductivity, making them attractive as a new class of candidate electrolytes in solid-state Li- and Na-ion batteries. However, further optimization of these materials requires a deeper understanding of the fundamental mechanisms underlying ultrafast ion conduction. To this end, we use ab initio molecular dynamics simulations and density-functional calculations to explore the motivations for cation diffusion. We find that superionic behavior in Li 2B 12H 12 and Na 2B 12H 12 results from a combination of key structural, chemical, and dynamical factors that introduce intrinsicmore » frustration and disorder. A statistical metric is used to show that the structures exhibit a high density of accessible interstitial sites and site types, which correlates with the flatness of the energy landscape and the observed cation mobility. Furthermore, cations are found to dock to specific anion sites, leading to a competition between the geometric symmetry of the anion and the symmetry of the lattice itself, which can facilitate cation hopping. Finally, facile anion reorientations and other low-frequency thermal vibrations lead to fluctuations in the local potential that enhance cation mobility by creating a local driving force for hopping. In conclusion, we discuss the relevance of each factor for developing new ionic conductivity descriptors that can be used for discovery and optimization of closo-borate solid electrolytes, as well as superionic conductors more generally.« less

Mechanical and electric characteristics of vacuum impregnated no-insulation HTS coil

NASA Astrophysics Data System (ADS)

Park, Heecheol; Kim, A.-rong; Kim, Seokho; Park, Minwon; Kim, Kwangmin; Park, Taejun

2014-09-01

For the conduction cooling application, epoxy impregnation is inevitable to enhance the thermal conduction. However, there have been several research results on the delamination problem with coated conductor and the main cause of the delamination is related with the different thermal contraction between epoxy, the insulation layer and the weak conductor. To avoid this problem, the amount of epoxy and insulation layer between conductors should be minimized or removed. Therefore, no insulation (NI) winding method and impregnation after dry winding can be considered to solve the problem. The NI coil winding method is very attractive due to high mechanical/thermal stability for the special purpose of DC magnets by removing the insulation layer. In this paper, the NI coil winding method and vacuum impregnation are applied to a HTS coil to avoid the delamination problem and enhance the mechanical/thermal stability for the conduction cooling application. Through the charging/discharging operation, electric/thermal characteristics are investigated at 77 K and 30 K.

Solid-Liquid Lithium Electrolyte Nanocomposites Derived from Porous Molecular Cages.

PubMed

Petronico, Aaron; Moneypenny, Timothy P; Nicolau, Bruno G; Moore, Jeffrey S; Nuzzo, Ralph G; Gewirth, Andrew A

2018-06-20

We demonstrate that solid-liquid nanocomposites derived from porous organic cages are effective lithium ion electrolytes at room temperature. A solid-liquid electrolyte nanocomposite (SLEN) fabricated from a LiTFSI/DME electrolyte system and a porous organic cage exhibits ionic conductivity on the order of 1 × 10 -3 S cm -1 . With an experimentally measured activation barrier of 0.16 eV, this composite is characterized as a superionic conductor. Furthermore, the SLEN displays excellent oxidative stability up to 4.7 V vs Li/Li + . This simple three-component system enables the rational design of electrolytes from tunable discrete molecular architectures.

Systems and methods for selective hydrogen transport and measurement

DOEpatents

Glatzmaier, Gregory C

2013-10-29

Systems and methods for selectively removing hydrogen gas from a hydrogen-containing fluid volume are disclosed. An exemplary system includes a proton exchange membrane (PEM) selectively permeable to hydrogen by exclusively conducting hydrogen ions. The system also includes metal deposited as layers onto opposite sides or faces of the PEM to form a membrane-electrode assembly (MEA), each layer functioning as an electrode so that the MEA functions as an electrochemical cell in which the ionic conductors are hydrogen ions, and the MEA functioning as a hydrogen selective membrane (HSM) when located at the boundary between a hydrogen-containing fluid volume and a second fluid.

Application of the Solubility Parameter Concept to the Design of Chemiresistor Arrays

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

Eastman, M.P.; Hughes, R.C.; Jenkins, M.W.

1999-01-11

Arrays of unheated chemically sensitive resistors (chemiresistors) can serve as extremely small, low-power-consumption sensors with simple read-out electronics. We report here results on carbon-loaded polymer composites, as well as polymeric ionic conductors, as chemiresistor sensors. We use the volubility parameter concept to understand and categorize the chemiresistor responses and, in particular, we compare chemiresistors fabricated from polyisobutylene (PIB) to results from PIB-coated acoustic wave sensors. One goal is to examine the possibility that a small number of diverse chemiresistors can sense all possible solvents-the "Universal Solvent Sensor Array". keywords: chemiresistor, volubility parameter, chemical sensor

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

Xian, Y. B.; Xu, H. T.; Lu, X. P., E-mail: luxinpei@hotmail.com

In this work, for better applications of atmospheric pressure plasma jets, the physics of plasma streamers in a glass tube with a part of it covered by a conductor is investigated. To better understand the propagation mechanism of plasma bullets in capillary tubes passing through a curved or narrow passage for some biomedical or material applications, the propagation of plasma streamers in a tube covered by a floating conductor is investigated. For a plasma streamer propagating in a tube covered by a conductor, the plasma streamer is suppressed and becomes shorter, and a secondary streamer is generated in the tubemore » at the downstream end of the conductor. The larger the area covered by the conductor, or the thinner the tube, the stronger the plasma streamer is inhibited. The electric potential of the conductor is measured to be as high as 6 kV. On the other hand, a higher voltage applied on the HV electrode, or a higher gas flow rate will make the secondary plasma streamer longer. It is found that the capacitor formed by the conductor outside the tube and the wall of the tube plays an important role in inhibiting the original plasma streamer and generating the secondary streamer. Moreover, the active species generated by the original plasma play important role in generating a secondary plasma streamer.« less

Mobility propagation and dynamic facilitation in superionic conductors

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

Annamareddy, Ajay, E-mail: vkannama@ncsu.edu; Eapen, Jacob, E-mail: jacob.eapen@ncsu.edu

2015-11-21

In an earlier work [V. A. Annamareddy et al., Phys. Rev. E 89, 010301(R) (2014)], we showed the manifestation of dynamical heterogeneity (DH)—the presence of clustered mobile and immobile regions—in UO{sub 2}, a model type II superionic conductor. In the current work, we demonstrate the mechanism of dynamic facilitation (DF) in two superionic conductors (CaF{sub 2} and UO{sub 2}) using atomistic simulations. Using the mobility transfer function, DF is shown to vary non-monotonically with temperature with the intensity of DF peaking at temperatures close to the superionic transition temperature (T{sub λ}). Both the metrics quantifying DH and DF show remarkablemore » correspondence implying that DF, in the framework of kinematically constrained models, underpins the heterogeneous dynamics in type II superionic conductors.« less

Nonvacuum, maskless fabrication of a flexible metal grid transparent conductor by low-temperature selective laser sintering of nanoparticle ink.

PubMed

Hong, Sukjoon; Yeo, Junyeob; Kim, Gunho; Kim, Dongkyu; Lee, Habeom; Kwon, Jinhyeong; Lee, Hyungman; Lee, Phillip; Ko, Seung Hwan

2013-06-25

We introduce a facile approach to fabricate a metallic grid transparent conductor on a flexible substrate using selective laser sintering of metal nanoparticle ink. The metallic grid transparent conductors with high transmittance (>85%) and low sheet resistance (30 Ω/sq) are readily produced on glass and polymer substrates at large scale without any vacuum or high-temperature environment. Being a maskless direct writing method, the shape and the parameters of the grid can be easily changed by CAD data. The resultant metallic grid also showed a superior stability in terms of adhesion and bending. This transparent conductor is further applied to the touch screen panel, and it is confirmed that the final device operates firmly under continuous mechanical stress.

Testing of a flat conductor cable baseboard system for residential and commercial wiring

NASA Technical Reports Server (NTRS)

Hankins, J. D.

1974-01-01

The results of extensive testing (mechanical, electrical, chemical, environmental, thermal, and analytical) are reported for a flat conductor cable baseboard system for residential and commercial wiring. In all of the tests, Underwriters Laboratories (UL) Standards, UL Tentative Test Programs, or Accepted Engineering Practices were followed during test selection, test setup, and test accomplishment.

Mechanical properties and XRD of Nafion modified by 2-hydroxyethylammonium ionic liquids

NASA Astrophysics Data System (ADS)

Garaev, V.; Pavlovica, S.; Reinholds, I.; Vaivars, G.

2013-12-01

In this work, the Nafion 112 membrane impregnated with 2-hydroxyethylammonium carboxylate ionic liquids have been investigated. The used ionic liquids were 2-hydroxyethylammonium formate [HEA]F, acetate [HEA]A and lactate [HEA]L. Prepared composite membranes Nafion/ionic liquid are characterized by mechanical testing, such as tensile test and creep test. It is found that ionic liquids decrease elastic modulus and creep compliance, but do not have significant effect on the tensile strength. Also, composite membranes were studied by wide angle X-ray diffraction. All ionic liquids shift the peak maximum to the lower angle. In this work, only biodegradable ionic liquids were used for composite preparation.

SAFETY SYSTEM FOR CONTROL ROD

DOEpatents

Paget, J.A.

1963-05-14

A structure for monitoring the structural continuity of a control rod foi a neutron reactor is presented. A electric conductor readily breakable under mechanical stress is fastened along the length of the control rod at a plurality of positions and forms a closed circuit with remote electrical components responsive to an open circuit. A portion of the conductor between the control rod and said components is helically wound to allow free and normally unrestricted movement of the segment of conductor secured to the control rod relative to the remote components. Any break in the circuit is indicative of control rod breakage. (AEC)

An L-band transit-time oscillator with mechanical frequency tunability

NASA Astrophysics Data System (ADS)

Song, Lili; He, Juntao; Ling, Junpu; Cao, Yibing

2017-02-01

An L-band coaxial Transit-time Oscillator (TTO) with mechanical frequency tunability is introduced in this paper. Particle-in-cell simulations have been done. The output power efficiency has been improved at least 20% under a 10.2 GW input power and with a tunable range from 1.57 GHz to 1.90 GHz by modulating the outer conductor. It is worth to note that the efficiency can reach as high as 41% at 1.75 GHz. The mechanical engineering method is also detailed in this work. The frequency tuning range of the coaxial TTO is 22.6% of the central frequency. On the other hand, the frequency can be tuned from 1.6 GHz to 1.85 GHz by modulating the inner conductor. The author highlights a hollow structure of the L-band coaxial TTO which can work from 1.03 GHz to 1.31 GHz via modulating the outer conductor in the rest of the article. The frequency tuning range of the hollow TTO is 21.4% of the central frequency. More importantly, the hollow TTO can be easily achieved after the inner conductor is removed from the coaxial TTO. The electric field distributions of the coaxial and hollow TTOs are analyzed, resulting in that the longitudinal and transverse working modes are TM01 and π mode, respectively. The same working mode from these two structures implies the stability of the TTOs mentioned above.

Development of an YBCO coil with SSTC conductors for high field application

NASA Astrophysics Data System (ADS)

Shi, Y.; Liu, H. J.; Liu, F.; Tan, Y. F.; Jin, H.; Yu, M.; Lei, L.; Guo, L.; Hong, Z. Y.

2018-07-01

With the continuous reduction of the production costs and improvement of the transport performance, YBCO coated conductor is the most promising candidate for the high field magnet application due to its high irreversibility field and strong mechanical properties. Presently a stable production capacity of the YBCO conductors has been achieved by Shanghai Superconducting Technology Co., Ltd (SSTC) in China. Therefore, the demand in high field application with YBCO conductors is growing in China. This paper describes the design, fabrication and preliminary experiment of a solenoid coil with YBCO conductors supplied by SSTC to validate the possibility of high field application. Four same double pancakes were manufactured and assembled for the YBCO coil where the outer diameter and height was 54.3 and 48 mm respectively to match the dimensional limitation of the 14 T background magnets. The critical current (Ic) of YBCO conductors was obtained by measuring as a function of the applied field perpendicular to the YBCO conductor surface which provides the necessary input parameters for preliminary performance evaluation of the coil. Finally the preliminary test and discussion at 77 and 4.2 K were carried out. The consistency of four double pancakes Ic was achieved. The measured results indicate that the fabrication technology of HTS coil is reliable which gives the conference for the in-field test in high field application. This YBCO coil is the first demonstration of the SSTC YBCO coated conductors.

Influence Of Zwitterions on Properties and Morphology of Ionomers: Implications for Electro-Active Applications

DTIC Science & Technology

2010-08-01

membranes in EMIm ES ionic liquid at 10 wt% IL concentration resulted in composites with similar mechanical performance, but 1. REPORT DATE (DD-MM...TERMS zwitterionomer, thermal mechanical property, morphology, ionic liquid , ionic conductivity, transducer Tianyu Wu, Rebecca H. Brown, Andrew J. Duncan...expected entanglement concentration. Swelling of the zwitterionomer membranes in EMIm ES ionic liquid at 10 wt% IL concentration resulted in

The mixed alkali effect in ionically conducting glasses revisited: a study by molecular dynamics simulation.

PubMed

Habasaki, Junko; Ngai, Kia L

2007-09-07

When more than two kinds of mobile ions are mixed in ionic conducting glasses and crystals, there is a non-linear decrease of the transport coefficients of either type of ion. This phenomenon is known as the mixed mobile ion effect or Mixed Alkali Effect (MAE), and remains an unsolved problem. We use molecular dynamics simulation to study the complex ion dynamics in ionically conducting glasses including the MAE. In the mixed alkali lithium-potassium silicate glasses and related systems, a distinct part of the van Hove functions reveals that jumps from one kind of site to another are suppressed. Although, consensus for the existence of preferential jump paths for each kind of mobile ions seems to have been reached amongst researchers, the role of network formers and the number of unoccupied ion sites remain controversial in explaining the MAE. In principle, these factors when incorporated into a theory can generate the MAE, but in reality they are not essential for a viable explanation of the ion dynamics and the MAE. Instead, dynamical heterogeneity and "cooperativity blockage" originating from ion-ion interaction and correlation are fundamental for the observed ion dynamics and the MAE. Suppression of long range motion with increased back-correlated motions is shown to be a cause of the large decrease of the diffusivity especially in dilute foreign alkali regions. Support for our conclusion also comes from the fact that these features of ion dynamics are common to other ionic conductors, which have no glassy networks, and yet they all exhibit the MAE.

Stress-dependent crystal structure of lanthanum strontium cobalt ferrite by in situ synchrotron X-ray diffraction

NASA Astrophysics Data System (ADS)

Geiger, Philipp T.; Khansur, Neamul H.; Riess, Kevin; Martin, Alexander; Hinterstein, Manuel; Webber, Kyle G.

2018-02-01

Lanthanum strontium cobalt ferrite La1-xSrxCo1-yFeyO3-δ (LSCF) is one of the most studied mixed ionic-electronic conductor materials due to electrical and transport properties, which are attractive for intermediate temperature solid oxide fuel cells (SOFCs), oxygen permeation membranes, and catalysis. The integration of such materials, however, depends on the thermal as well as mechanical behavior. LSCF exhibits nonlinear hysteresis during compressive stress-strain measurements, marked by a remanent strain and coercive stress, i.e., ferroelasticity. However, the origin of ferroelastic behavior has not been investigated under high compressive stress. This study, therefore, investigates the microscopic origin of stress-induced mechanical behavior in polycrystalline (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ using in situ synchrotron x-ray diffraction. The data presented here reveals that the strain response originates from the intrinsic lattice strain as well as the extrinsic domain switching strain without any apparent change in crystallographic symmetry. A comparison of the calculated microscopic strain contribution with that of a macroscopic measurement indicates a significant change in the relative contributions of intrinsic and extrinsic strain depending on the applied stress state, i.e., under maximum stress and after unloading. Direct evidence of the microscopic origin of stress-strain response outlined in this paper may assist in guiding materials design with the improved mechanical reliability of SOFCs.

High field superconductors for superconducting machines

NASA Astrophysics Data System (ADS)

Rupp, G.; Wilhelm, M.; Wohlleben, K.; Ziegler, G.; Springer, E.

1980-11-01

High current capacity Nb3Sn multifilament conductors were fabricated. A solid state diffusion process was used. The number of conductor filaments approaches 70,000 with filament diameters being approximately 1.5 microns. Effective current densities reach 86,000 A/sq cm at a magnetic flux density of 10 T and operating temperature of 4.2 K. Calibrated flattened cables of twisted strands were fabricated for higher currents (up to 1000 A at 10 T). Generally, quantitative relations can be given for the rise in the critical current of Nb3Sn multifilament conductors, observed under the influence of mechanical stresses. Long lengths (km) of these conductors were used to manufacture superconducting solenoids two different ways. These rise to the short sample current, usually without conditioning, and deliver magnetic flux densities up to 14 T with an 8.5 T NbTi background field.

Manufacturing and test of 2G-HTS coils for rotating machines: Challenges, conductor requirements, realization

NASA Astrophysics Data System (ADS)

Oomen, Marijn; Herkert, Werner; Bayer, Dietmar; Kummeth, Peter; Nick, Wolfgang; Arndt, Tabea

2012-11-01

We investigate the use of 2nd-generation High-Temperature Superconductors (2G-HTSs) in the rotors of electrical motors and generators. For these devices the conductor must be wound into robust impregnated coils, which are operated in vacuum at temperatures around 30 K, in strong magnetic fields of about 2T. Differences in thermal contraction between the coil former, conductor constituents, impregnation resin, bandage and heat-sink materials (assembled at room temperature) cause mechanical stresses at operating temperature. Rotating-machine operation adds Lorentz forces and challenging centripetal accelerations up to thousands of g. Second generation-HTS conductors withstand large tensile stresses in axial direction and compression in normal direction. However, shear stresses, axial compression, and tension normal to the conductor can cause degradation in superconducting properties. Such stresses can be mitigated by correct choice of materials, coil lay-out and manufacturing process. A certain stress level will remain, which the conductor must withstand. We have manufactured many impregnated round and race-track coils, using different 2G-HTS conductors, and tested them at temperatures from 25 K to 77 K. Degradation of the superconductor in early coils was traced to the mentioned differences in thermal contraction, and was completely avoided in coils produced later. We will discuss appropriate coil-winding techniques to assure robust and reliable superconductor performance.

Giant thermally-enhanced electrostriction and polar surface phase in L a2M o2O9 oxygen ion conductors

NASA Astrophysics Data System (ADS)

Li, Qian; Lu, Teng; Schiemer, Jason; Laanait, Nouamane; Balke, Nina; Zhang, Zhan; Ren, Yang; Carpenter, Michael A.; Wen, Haidan; Li, Jiangyu; Kalinin, Sergei V.; Liu, Yun

2018-04-01

Ferroelectrics possess spontaneous electric polarization at macroscopic scales which nonetheless imposes strict limitations on the material classes. Recent discoveries of untraditional symmetry-breaking phenomena in reduced material dimensions have indicated feasibilities to extend polar properties to broader types of materials, potentially opening up the freedom for designing materials with hybrid functionalities. Here, we report the unusual electromechanical properties of L a2M o2O9 (LAMOX) oxygen ion conductors, systematically investigated at both bulk and surface length levels. We first observed giant electrostriction effects in L a2M o2O9 bulk ceramics that are thermally enhanced in concert with their low-energy oxygen-vacancy hopping dynamics. Moreover, while no clear bulk polarization was detected, the surface phases of LAMOX were found to be manifestly polar, likely originating from the coupling between the intrinsic structural flexibilities with strain gradients (i.e., flexoelectricity) and/or chemical heterogeneities present in the materials. These findings identify L a2M o2O9 as a promising electromechanical material system and suggest that the flexible structural and chemical configurations in ionically active materials could enable fundamentally different venues to accommodate electric polarization.

Streaming current magnetic fields in a charged nanopore.

PubMed

Mansouri, Abraham; Taheri, Peyman; Kostiuk, Larry W

2016-11-11

Magnetic fields induced by currents created in pressure driven flows inside a solid-state charged nanopore were modeled by numerically solving a system of steady state continuum partial differential equations, i.e., Poisson, Nernst-Planck, Ampere and Navier-Stokes equations (PNPANS). This analysis was based on non-dimensional transport governing equations that were scaled using Debye length as the characteristic length scale, and applied to a finite length cylindrical nano-channel. The comparison of numerical and analytical studies shows an excellent agreement and verified the magnetic fields density both inside and outside the nanopore. The radially non-uniform currents resulted in highly non-uniform magnetic fields within the nanopore that decay as 1/r outside the nanopore. It is worth noting that for either streaming currents or streaming potential cases, the maximum magnetic field occurred inside the pore in the vicinity of nanopore wall, as opposed to a cylindrical conductor that carries a steady electric current where the maximum magnetic fields occur at the perimeter of conductor. Based on these results, it is suggested and envisaged that non-invasive external magnetic fields readouts generated by streaming/ionic currents may be viewed as secondary electronic signatures of biomolecules to complement and enhance current DNA nanopore sequencing techniques.

Double perovskite cathodes for proton-conducting ceramic fuel cells: are they triple mixed ionic electronic conductors?

NASA Astrophysics Data System (ADS)

Téllez Lozano, Helena; Druce, John; Cooper, Samuel J.; Kilner, John A.

2017-12-01

18O and 2H diffusion has been investigated at a temperature of 300 °C in the double perovskite material PrBaCo2O5+δ (PBCO) in flowing air containing 200 mbar of 2H216O. Secondary ion mass spectrometry (SIMS) depth profiling of exchanged ceramics has shown PBCO still retains significant oxygen diffusivity ( 1.3 × 10-11 cm2s-1) at this temperature and that the presence of water (2H216O), gives rise to an enhancement of the surface exchange rate over that in pure oxygen by a factor of 3. The 2H distribution, as inferred from the 2H216O- SIMS signal, shows an apparent depth profile which could be interpreted as 2H diffusion. However, examination of the 3-D distribution of the signal shows it to be nonhomogeneous and probably related to the presence of hydrated layers in the interior walls of pores and is not due to proton diffusion. This suggests that PBCO acts mainly as an oxygen ion mixed conductor when used in PCFC devices, although the presence of a small amount of protonic conductivity cannot be discounted in these materials.

Streaming current magnetic fields in a charged nanopore

NASA Astrophysics Data System (ADS)

Mansouri, Abraham; Taheri, Peyman; Kostiuk, Larry W.

2016-11-01

Magnetic fields induced by currents created in pressure driven flows inside a solid-state charged nanopore were modeled by numerically solving a system of steady state continuum partial differential equations, i.e., Poisson, Nernst-Planck, Ampere and Navier-Stokes equations (PNPANS). This analysis was based on non-dimensional transport governing equations that were scaled using Debye length as the characteristic length scale, and applied to a finite length cylindrical nano-channel. The comparison of numerical and analytical studies shows an excellent agreement and verified the magnetic fields density both inside and outside the nanopore. The radially non-uniform currents resulted in highly non-uniform magnetic fields within the nanopore that decay as 1/r outside the nanopore. It is worth noting that for either streaming currents or streaming potential cases, the maximum magnetic field occurred inside the pore in the vicinity of nanopore wall, as opposed to a cylindrical conductor that carries a steady electric current where the maximum magnetic fields occur at the perimeter of conductor. Based on these results, it is suggested and envisaged that non-invasive external magnetic fields readouts generated by streaming/ionic currents may be viewed as secondary electronic signatures of biomolecules to complement and enhance current DNA nanopore sequencing techniques.

A Dual-Phase Ceramic Membrane with Extremely High H2 Permeation Flux Prepared by Autoseparation of a Ceramic Precursor.

PubMed

Cheng, Shunfan; Wang, Yanjie; Zhuang, Libin; Xue, Jian; Wei, Yanying; Feldhoff, Armin; Caro, Jürgen; Wang, Haihui

2016-08-26

A novel concept for the preparation of multiphase composite ceramics based on demixing of a single ceramic precursor has been developed and used for the synthesis of a dual-phase H2 -permeable ceramic membrane. The precursor BaCe0.5 Fe0.5 O3-δ decomposes on calcination at 1370 °C for 10 h into two thermodynamically stable oxides with perovskite structures: the cerium-rich oxide BaCe0.85 Fe0.15 O3-δ (BCF8515) and the iron-rich oxide BaCe0.15 Fe0.85 O3-δ (BCF1585), 50 mol % each. In the resulting dual-phase material, the orthorhombic perovskite BCF8515 acts as the main proton conductor and the cubic perovskite BCF1585 as the main electron conductor. The dual-phase membrane shows an extremely high H2 permeation flux of 0.76 mL min(-1)  cm(-2) at 950 °C with 1.0 mm thickness. This auto-demixing concept should be applicable to the synthesis of other ionic-electronic conducting ceramics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exfoliated YBCO filaments for second-generation superconducting cable

NASA Astrophysics Data System (ADS)

Solovyov, Vyacheslav; Farrell, Paul

2017-01-01

The second-generation high temperature superconductor (2G HTS) wire is the most promising conductor for high-field magnets such as accelerator dipoles and compact fusion devices. The key element of the wire is a thin Y1Ba2Cu3O7 (YBCO) layer deposited on a flexible metal substrate. The substrate, which becomes incorporated in the 2G conductor, reduces the electrical and mechanical performance of the wire. This is a process that exfoliates the YBCO layer from the substrate while retaining the critical current density of the superconductor. Ten-centimeter long coupons of exfoliated YBCO layers were manufactured, and detailed structural, electrical, and mechanical characterization were reported. After exfoliation, the YBCO layer was supported by a 75 μm thick stainless steel foil, which makes for a compact, mechanically stronger, and inexpensive conductor. The critical current density of the filaments was measured at both 77 K and 4.2 K. The exfoliated YBCO retained 90% of the original critical current. Similarly, tests in an external magnetic field at 4.2 K confirmed that the pinning strength of the YBCO layer was also retained following exfoliation.

Upgrades to the NSTX HHFW antenna

NASA Astrophysics Data System (ADS)

Ellis, R.; Brunkhorst, C.; Hosea, J.

2014-02-01

The High Harmonic Fast Wave (HHFW) antenna for the National Spherical Torus Experiment (NSTX) at PPPL will be upgraded as part of the NSTX upgrade project. Higher magnetic fields and plasma current result in disruption forces on the current straps that can be up to four times the original design values. The current straps on the HHFW antenna are presently fed by coaxial feedthroughs with rigid center conductors. The additional forces on the current straps require a compliant section in the center conductor in order to minimize the forces on the feedthrough. The design of this compliant section has been an integrated effort involving electrostatic calculations in parallel with mechanical and thermal analyses, in order to arrive at a design that is optimized for mechanical, thermal and electrical considerations. The voltage standoff obtained from this design will be verified when a prototype antenna is evaluated on our RF test stand. This paper describes the design of the compliant section of the center conductor, mechanical, thermal and electrostatic calculations, and plans for full implementation of the upgrade on NSTX.

Towards a lattice-matching solid-state battery: synthesis of a new class of lithium-ion conductors with the spinel structure.

PubMed

Rosciano, Fabio; Pescarmona, Paolo P; Houthoofd, Kristof; Persoons, Andre; Bottke, Patrick; Wilkening, Martin

2013-04-28

Lithium ion batteries have conquered most of the portable electronics market and are now on the verge of deployment in large scale applications. To be competitive in the automotive and stationary sectors, however, they must be improved in the fields of safety and energy density (W h L(-1)). Solid-state batteries with a ceramic electrolyte offer the necessary advantages to significantly improve the current state-of-the-art technology. The major limit towards realizing a practical solid-state lithium-ion battery lies in the lack of viable ceramic ionic conductors. Only a few candidate materials are available, each carrying a difficult balance between advantages and drawbacks. Here we introduce a new class of possible solid-state lithium-ion conductors with the spinel structure. Such compounds could be coupled with spinel-type electrode materials to obtain a "lattice matching" solid device where low interfacial resistance could be achieved. Powders were prepared by wet chemistry, their structure was studied by means of diffraction techniques and magic angle spinning NMR, and Li(+) self-diffusion was estimated by static NMR line shape measurements. Profound differences in the Li(+) diffusion properties were observed depending on the composition, lithium content and cationic distribution. Local Li(+) hopping in the spinel materials is accompanied by a low activation energy of circa 0.35 eV being comparable with that of, e.g., LLZO-type garnets, which represent the current benchmark in this field. We propose these novel materials as a building block for a lattice-matching all-spinel solid-state battery with low interfacial resistance.

A base-metal conductor system for silicon solar cells

NASA Technical Reports Server (NTRS)

Coleman, M. G.; Pryor, R. A.; Sparks, T. G.

1980-01-01

Solder, copper, and silver are evaluated as conductor layer metals for silicon solar cell metallization on the basis of metal price stability and reliability under operating conditions. Due to its properties and cost, copper becomes an attractive candidate for the conductor layer. It is shown that nickel operates as an excellent diffusion barrier between copper and silicon while simultaneously serving as an electrical contact and mechanical contact to silicon. The nickel-copper system may be applied to the silicon by plating techniques utilizing a variety of plating bath compositions. Solar cells having excellent current-voltage characteristics are fabricated to demonstrate the nickel-copper metallization system.

A high-conduction Ge substituted Li3AsS4 solid electrolyte with exceptional low activation energy

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

Sahu, Gayatri; Rangasamy, Ezhiylmurugan; Li, Juchuan

2014-04-16

In lithium-ion conducting solid electrolytes the potential to enable high-energy-density secondary batteries and offer distinctive safety features as an advantage over traditional liquid electrolytes is shown. Achieving the combination of high ionic conductivity, low activation energy, and outstanding electrochemical stability in crystalline solid electrolytes is a challenge for the synthesis of novel solid electrolytes. We report an exceptionally low activation energy (Ea) and high room temperature superionic conductivity via facile aliovalent substitution of Li 3AsS 4 by Ge, which increased the conductivity by two orders of magnitude as compared to the parent compound. The composition Li 3.334Ge 0.334As 0.666S 4more » has a high ionic conductivity of 1.12 mScm -1 at 27°C. Local Li + hopping in this material is accompanied by distinctive low activation energy Ea of 0.17 eV being the lowest of Li + solid conductors. Finally, our study demonstrates the efficacy of surface passivation of solid electrolyte to achieve compatibility with metallic lithium electrodes.« less

Spectroscopic Study of Local Interactions of Platinum in Small [CexOy]Ptx' - Clusters

NASA Astrophysics Data System (ADS)

Ray, Manisha; Kafader, Jared O.; Chick Jarrold, Caroline

2016-06-01

Cerium oxide is a good ionic conductor, and the conductivity can be enhanced with oxygen vacancies and doping. This conductivity may play an important role in the enhancement of noble or coinage metal toward the water-gas shift reaction when supported by cerium oxide. The ceria-supported platinum catalyst in particular has received much attention because of higher activity at lower temperatures (LT) compared to the most common commercial LT-WGS catalyst. We have used a combination of anion photoelectron spectroscopy and density functional theory calculations to study the interesting molecular and electronic structures and properties of cluster models of ceria-supported platinum. [CexOy]Ptx' - (x,x'=1,2 ; y≤2x') clusters exhibit evidence of ionic bonding possible because of the high electron affinity of Pt and the low ionization potential of cerium oxide clusters. In addition, Pt- is a common daughter ion resulting from photodissociation of [CexOy]Ptx' - clusters. Finally, several of the anion and neutral clusters have profoundly different structures. These features may play a role in the enhancement of catalytic activity toward the water-gas shift reaction.

Heterogeneous Nature of Relaxation Dynamics of Room-Temperature Ionic Liquids (EMIm) 2[Co(NCS) 4] and (BMIm) 2[Co(NCS) 4

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

Hensel-Bielowka, Stella; Wojnarowska, Zaneta; Dzida, Marzena

2015-08-11

Dynamic crossover above T g has been recognized as a characteristic feature of molecular dynamics of liquids approaching glass transition. Experimentally, it is manifested as a change in Vogel–Fulcher–Tammann dependence or a breakdown of the Stokes–Einstein and related relations. In this study, we report the exception from this rather general pattern of behavior. By means of dielectric, ultrasonic, rheological, and calorimetric methods, dynamics of two good ionic conductors (BMIm) 2[Co(NCS) 4] and (EMIm) 2[Co(NCS) 4] of less common stoichiometry (2:1) was studied in a very broad temperature range. However, none of the mentioned dynamic changes was observed in the entiremore » studied temperature range. On the contrary, the single VFT and the same fractional Walden coefficient were found for conductivity and viscosity changes over 12 decades. Finally and moreover, ultrasonic studies revealed that the data at temperatures which cover the normal liquid region cannot be fitted by a single exponential decay, and the Cole–Cole function should be used instead.« less

Heterogeneous nature of relaxation dynamics of room-temperature ionic liquids (EMIm) 2[Co(NCS) 4] and (BMIm) 2[Co(NCS) 4

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

Hensel-Bielowka, Stella; Wojnarowska, Zaneta E.; Dzida, Marzena

2015-08-11

Dynamic crossover above T g has been recognized as a characteristic feature of molecular dynamics of liquids approaching glass transition. Experimentally, it is manifested as a change in Vogel Fulcher Tammann dependence or a breakdown of the Stokes Einstein and related relations. In this paper, we report the exception from this rather general pattern of behavior. By means of dielectric, ultrasonic, rheological, and calorimetric methods, dynamics of two good ionic conductors (BMIm) 2[Co(NCS) 4] and (EMIm) 2[Co(NCS) 4] of less common stoichiometry (2:1) was studied in a very broad temperature range. However, none of the mentioned dynamic changes was observedmore » in the entire studied temperature range. On the contrary, the single VFT and the same fractional Walden coefficient were found for conductivity and viscosity changes over 12 decades. Furthermore, ultrasonic studies revealed that the data at temperatures which cover the normal liquid region cannot be fitted by a single exponential decay, and the Cole Cole function should be used instead.« less

Fabrication and surface enhanced Raman scattering effect of centimeter level AgCuAu composite nanowires

NASA Astrophysics Data System (ADS)

Xu, Dapeng; Zhang, Song; Yang, Wei; Chen, Jian

2017-10-01

Centimeter level AgCuAu composite nanowires were prepared by a solid-state ionics method under a direct current electric field (DCEF) using fast ionic conductor RbAg4I5 films and vacuum thermal evaporation method. The surface morphology and chemical composition of the AuAgCu composite nanowires were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. Raman enhancement performance of the AgCuAu composite nanowires substrates was detected by Rhodamine 6G (R6G) aqueous solutions as probe molecules. Long-range order and short-range order AgCuAu composite nanowires with the length of 1 cm were prepared. The nanowires were bamboo-shaped with high surface roughness and the diameters of nanowires ranged from 60 to 100 nm. The molar ratio of Ag:Cu:Au in composite nanowires is 15:2:1. The intrinsic Raman peaks of 10-16 mol/L R6G at 612, 773, 1125, 1182, 1307, 1361, 1418, 1506, 1545, 1575, 1597, 1650 cm-1 are all present when AgCuAu composite nanowires were used as the SERS substrates.

The Electrochemical Properties of Sr(Ti,Fe)O 3-δ for Anodes in Solid Oxide Fuel Cells

DOE PAGES

Nenning, Andreas; Volgger, Lukas; Miller, Elizabeth; ...

2017-02-18

Reduction-stable mixed ionic and electronic conductors such as Sr(Ti,Fe)O 3-δ (STF) are promising materials for application in anodes of solid oxide fuel cells. The defect chemistry of STF and its properties as solid oxide fuel cell (SOFC) cathode have been studied thoroughly, while mechanistic investigations of its electrochemical properties as SOFC anode material are still scarce. In this study, thin film model electrodes of STF with 30% and 70% Fe content were investigated in H 2+H 2O atmosphere by electrochemical impedance spectroscopy. Lithographically patterned thin film Pt current collectors were applied on top or beneath the STF thin films tomore » compensate for the low electronic conductivity under reducing conditions. Oxygen exchange resistances, electronic and ionic conductivities and chemical capacitances were quantified and discussed in a defect chemical model. Increasing Fe content increases the electro-catalytic activity of the STF surface as well as the electronic and ionic conductivity. Current collectors on top also increase the electrochemical activity due to a highly active Pt-atmosphere-STF triple phase boundary. Furthermore, the electrochemical activity depends decisively on the H 2:H 2O mixing ratio and the polarization. Lastly, Fe 0 nanoparticles may evolve on the surface in hydrogen rich atmospheres and increase the hydrogen adsorption rate.« less

Ionomer-Liquid Electrolyte Hybrid Ionic Conductor for High Cycling Stability of Lithium Metal Electrodes

PubMed Central

Song, Jongchan; Lee, Hongkyung; Choo, Min-Ju; Park, Jung-Ki; Kim, Hee-Tak

2015-01-01

The inhomogeneous Li electrodeposition of lithium metal electrode has been a major impediment to the realization of rechargeable lithium metal batteries. Although single ion conducting ionomers can induce more homogeneous Li electrodeposition by preventing Li+ depletion at Li surface, currently available materials do not allow room-temperature operation due to their low room temperature conductivities. In the paper, we report that a highly conductive ionomer/liquid electrolyte hybrid layer tightly laminated on Li metal electrode can realize stable Li electrodeposition at high current densities up to 10 mA cm−2 and permit room-temperature operation of corresponding Li metal batteries with low polarizations. The hybrid layer is fabricated by laminating few micron-thick Nafion layer on Li metal electrode followed by soaking 1 M LiPF6 EC/DEC (1/1) electrolyte. The Li/Li symmetric cell with the hybrid layer stably operates at a high current density of 10 mA cm−2 for more than 2000 h, which corresponds to more than five-fold enhancement compared with bare Li metal electrode. Also, the prototype Li/LiCoO2 battery with the hybrid layer offers cycling stability more than 350 cycles. These results demonstrate that the hybrid strategy successfully combines the advantages of bi-ionic liquid electrolyte (fast Li+ transport) and single ionic ionomer (prevention of Li+ depletion). PMID:26411701

Enhanced ionic conductivity with Li{sub 7}O{sub 2}Br{sub 3} phase in Li{sub 3}OBr anti-perovskite solid electrolyte

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

Zhu, Jinlong, E-mail: jlzhu04@physics.unlv.edu, E-mail: yusheng.zhao@unlv.edu, E-mail: zhaoys@sustc.edu.cn; Li, Shuai; Zhang, Yi

Cubic anti-perovskites with general formula Li{sub 3}OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li{sub 3}OBr and layered Li{sub 7}O{sub 2}Br{sub 3,} by solid state reaction routes. The results indicate that with the phase fraction of Li{sub 7}O{sub 2}Br{sub 3} increasing to 44 wt.more » %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li{sub 3}OBr. Formation energy calculations revealed the meta-stable nature of Li{sub 7}O{sub 2}Br{sub 3}, which supports the great difficulty in producing phase-pure Li{sub 7}O{sub 2}Br{sub 3} at ambient pressure. Methods of obtaining phase-pure Li{sub 7}O{sub 2}Br{sub 3} will continue to be explored, including both high pressure and metathesis techniques.« less

Alkali oxide-tantalum, niobium and antimony oxide ionic conductors

NASA Technical Reports Server (NTRS)

Roth, R. S.; Brower, W. S.; Parker, H. S.; Minor, D. B.; Waring, J. L.

1975-01-01

The phase equilibrium relations of four systems were investigated in detail. These consisted of sodium and potassium antimonates with antimony oxide and tantalum and niobium oxide with rubidium oxide as far as the ratio 4Rb2O:llB2O5 (B=Nb, Ta). The ternary system NaSbO3-Sb2O4-NaF was investigated extensively to determine the actual composition of the body centered cubic sodium antimonate. Various other binary and ternary oxide systems involving alkali oxides were examined in lesser detail. The phases synthesized were screened by ion exchange methods to determine mobility of the mobility of the alkali ion within the niobium, tantalum or antimony oxide (fluoride) structural framework. Five structure types warranted further investigation; these structure types are (1) hexagonal tungsten bronze (HTB), (2) pyrochlore, (3) the hybrid HTB-pyrochlore hexagonal ordered phases, (4) body centered cubic antimonates and (5) 2K2O:3Nb2O5. Although all of these phases exhibit good ion exchange properties only the pyrochlore was prepared with Na(+) ions as an equilibrium phase and as a low porosity ceramic. Sb(+3) in the channel interferes with ionic conductivity in this case, although relatively good ionic conductivity was found for the metastable Na(+) ion exchanged analogs of RbTa2O5F and KTaWO6 pyrochlore phases.

Ionomer-Liquid Electrolyte Hybrid Ionic Conductor for High Cycling Stability of Lithium Metal Electrodes

NASA Astrophysics Data System (ADS)

Song, Jongchan; Lee, Hongkyung; Choo, Min-Ju; Park, Jung-Ki; Kim, Hee-Tak

2015-09-01

The inhomogeneous Li electrodeposition of lithium metal electrode has been a major impediment to the realization of rechargeable lithium metal batteries. Although single ion conducting ionomers can induce more homogeneous Li electrodeposition by preventing Li+ depletion at Li surface, currently available materials do not allow room-temperature operation due to their low room temperature conductivities. In the paper, we report that a highly conductive ionomer/liquid electrolyte hybrid layer tightly laminated on Li metal electrode can realize stable Li electrodeposition at high current densities up to 10 mA cm-2 and permit room-temperature operation of corresponding Li metal batteries with low polarizations. The hybrid layer is fabricated by laminating few micron-thick Nafion layer on Li metal electrode followed by soaking 1 M LiPF6 EC/DEC (1/1) electrolyte. The Li/Li symmetric cell with the hybrid layer stably operates at a high current density of 10 mA cm-2 for more than 2000 h, which corresponds to more than five-fold enhancement compared with bare Li metal electrode. Also, the prototype Li/LiCoO2 battery with the hybrid layer offers cycling stability more than 350 cycles. These results demonstrate that the hybrid strategy successfully combines the advantages of bi-ionic liquid electrolyte (fast Li+ transport) and single ionic ionomer (prevention of Li+ depletion).

Synthesis, Characterization and Application of Functional Carbon Nano Materials

DTIC Science & Technology

2014-05-05

properties All nanotubes are expected to be very good thermal conductors along the tube, exhibiting a 12 property known as "ballistic conduction ...by approximately the same value (2.3%) [86]. 5) Thermal properties [87] Graphene is a perfect thermal conductor . Its thermal conductivity at room...other fields of materials science and technology. In particular, owing to their extraordinary thermal conductivity and mechanical and electrical

Thermal Decomposition Mechanisms of Alkylimidazolium Ionic Liquids with CN-containing Anions

DTIC Science & Technology

2014-11-01

anion calculated at the M06/6-31+G(d,p) level of theory and using the generic ionic liquid (GIL) model to simulate the condensed phase methyl...decomposition mechanisms of alkylimidazolium ionic liquids with CN-containing anions 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...perform, display, or disclose the work. 14. ABSTRACT Due to the unusually high heats of vaporization of room-temperature ionic liquids (RTILs

Self-consistent modeling of electrochemical strain microscopy of solid electrolytes

DOE PAGES

Tselev, Alexander; Morozovska, Anna N.; Udod, Alexei; ...

2014-10-10

Electrochemical strain microscopy (ESM) employs a strong electromechanical coupling in solid ionic conductors to map ionic transport and electrochemical processes with nanometer-scale spatial resolution. To elucidate the mechanisms of the ESM image formation, we performed self-consistent numerical modeling of the electromechanical response in solid electrolytes under the probe tip in a linear, small-signal regime using the Boltzmann–Planck–Nernst–Einstein theory and Vegard's law while taking account of the electromigration and diffusion. We identified the characteristic time scales involved in the formation of the ESM response and found that the dynamics of the charge carriers in the tip-electrolyte system with blocking interfaces canmore » be described as charging of the diffuse layer at the tip-electrolyte interface through the tip contact spreading resistance. At the high frequencies used in the detection regime, the distribution of the charge carriers under the tip is governed by evanescent concentration waves generated at the tip-electrolyte interface. The ion drift length in the electric field produced by the tip determines the ESM response at high frequencies, which follows a 1/f asymptotic law. The electronic conductivity, as well as the electron transport through the electrode-electrolyte interface, do not have a significant effect on the ESM signal in the detection regime. The results indicate, however, that for typical solid electrolytes at room temperature, the ESM response originates at and contains information about the very surface layer of a sample, and the properties of the one-unit-cell-thick surface layer may significantly contribute to the ESM response, implying a high surface sensitivity and a high lateral resolution of the technique. On the other hand, it follows that a rigorous analysis of the ESM signals requires techniques that account for the discrete nature of a solid.« less

Phase transition in lithium garnet oxide ionic conductors Li7La3Zr2O12: The role of Ta substitution and H2O/CO2 exposure

NASA Astrophysics Data System (ADS)

Wang, Yuxing; Lai, Wei

2015-02-01

High Li-content lithium garnet oxides are promising solid electrolyte materials for lithium batteries. Being the highest Li-content lithium garnet oxides, Li7La3Zr2O12 has been reported to crystallize in either the tetragonal or cubic phase with no consensus on the exact conditions under which these two phases are formed, which may be due to unintentional Al contamination and air exposure. In this work, the effects of Ta substitution and H2O/CO2 exposure have been studied under Al-contamination free conditions with minimal air exposure. We showed that 1) the Ta-substitution induced phase transition occurred through a two-phase mechanism and a minimum 0.6 mol of Ta substitution to Zr is needed to stabilize the cubic phase; 2) H2O and CO2 can individually induce the tetragonal-cubic phase transition in Li7La3Zr2O12 through proton exchange and Li extraction, respectively, which can have great influence on the transport properties of Li7La3Zr2O12.

Electric modulation of conduction in multiferroic Ca-doped BiFeO3 films.

PubMed

Yang, C-H; Seidel, J; Kim, S Y; Rossen, P B; Yu, P; Gajek, M; Chu, Y H; Martin, L W; Holcomb, M B; He, Q; Maksymovych, P; Balke, N; Kalinin, S V; Baddorf, A P; Basu, S R; Scullin, M L; Ramesh, R

2009-06-01

Many interesting materials phenomena such as the emergence of high-Tc superconductivity in the cuprates and colossal magnetoresistance in the manganites arise out of a doping-driven competition between energetically similar ground states. Doped multiferroics present a tantalizing evolution of this generic concept of phase competition. Here, we present the observation of an electronic conductor-insulator transition by control of band-filling in the model antiferromagnetic ferroelectric BiFeO3 through Ca doping. Application of electric field enables us to control and manipulate this electronic transition to the extent that a p-n junction can be created, erased and inverted in this material. A 'dome-like' feature in the doping dependence of the ferroelectric transition is observed around a Ca concentration of approximately 1/8, where a new pseudo-tetragonal phase appears and the electric modulation of conduction is optimized. Possible mechanisms for the observed effects are discussed on the basis of the interplay of ionic and electronic conduction. This observation opens the door to merging magnetoelectrics and magnetoelectronics at room temperature by combining electronic conduction with electric and magnetic degrees of freedom already present in the multiferroic BiFeO3.

Electric modulation of conduction in multiferroic Ca-doped BiFeO3 films

NASA Astrophysics Data System (ADS)

Yang, C.-H.; Seidel, J.; Kim, S. Y.; Rossen, P. B.; Yu, P.; Gajek, M.; Chu, Y. H.; Martin, L. W.; Holcomb, M. B.; He, Q.; Maksymovych, P.; Balke, N.; Kalinin, S. V.; Baddorf, A. P.; Basu, S. R.; Scullin, M. L.; Ramesh, R.

2009-06-01

Many interesting materials phenomena such as the emergence of high-Tc superconductivity in the cuprates and colossal magnetoresistance in the manganites arise out of a doping-driven competition between energetically similar ground states. Doped multiferroics present a tantalizing evolution of this generic concept of phase competition. Here, we present the observation of an electronic conductor-insulator transition by control of band-filling in the model antiferromagnetic ferroelectric BiFeO3 through Ca doping. Application of electric field enables us to control and manipulate this electronic transition to the extent that a p-n junction can be created, erased and inverted in this material. A `dome-like' feature in the doping dependence of the ferroelectric transition is observed around a Ca concentration of ~1/8, where a new pseudo-tetragonal phase appears and the electric modulation of conduction is optimized. Possible mechanisms for the observed effects are discussed on the basis of the interplay of ionic and electronic conduction. This observation opens the door to merging magnetoelectrics and magnetoelectronics at room temperature by combining electronic conduction with electric and magnetic degrees of freedom already present in the multiferroic BiFeO3.

Reliability of large superconducting magnets through design

NASA Astrophysics Data System (ADS)

Henning, C. D.

1981-01-01

Design and quality control of large superconducting magnets for reliability comparable to pressure vessels are discussed. The failure modes are analyzed including thermoelectric instabilities, electrical shorts, cryogenic/vacuum defects, and mechanical malfunctions. Design must take into consideration conductor stability, insulation based on the Paschen curves, and the possible burnout of cryogenic transition leads if the He flow is interrupted. The final stage of the metal drawing process should stress the superconductor material to a stress value higher than the magnet design stress, cabled conductors should be used to achieve mechanical redundancy, and ground-plane insulation must be multilayered for arc prevention.

Method for eliminating gas blocking in electrokinetic pumping systems

DOEpatents

Arnold, Don W.; Paul, Phillip H.; Schoeniger, Joseph S.

2001-09-11

A method for eliminating gas bubble blockage of current flow during operation of an electrokinetic pump. By making use of the ability to modify the surface charge on the porous dielectric medium used in electrokinetic pumps, it becomes possible to place electrodes away from the pressurized region of the electrokinetic pump. While gas is still generated at the electrodes they are situated such that the generated gas can escape into a larger buffer reservoir and not into the high pressure region of the pump where the gas bubbles can interrupt current flow. Various combinations of porous dielectric materials and ionic conductors can be used to create pumps that have desirable electrical, material handling, and flow attributes.

The solvated electron battery

NASA Astrophysics Data System (ADS)

Bennett, J.; Harney, D.; Mitchell, T.

A novel ambient temperture secondary battery using sodium and sulfur dissolved in liquid ammonia is being developed at ELTECH Systems corpooration. The key element of the system is the solvated electron electrode, a metallic liquid which is formed by ammonia and a number of alkali and alkaline earth metals. These solutions are excellent ionic and electronic conductors and have been shown to contain 'free' solvated electrons as the anionic species in solution. Sulfur was chosen as the cathodic reactant because of its high solubility in ammonia, and also because of the high solubiity and good conductivity of the polysulfide reaction products. Development efforts have thus far concentrated on basic electrochemical measurements and establishment of system feasibility.

Electromechanical properties of superconductors for DOE fusion applications

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

Ekin, J.W.; Moreland, J.; Brauch, J.C.

1986-03-01

This is an interim report presenting data on superconductor performance under mechanical load, which are needed for the selection of superconductors and the mechanical design of superconducting magnets for DOE fusion energy systems. A further aim of the reported research is to measure and understand the electromechanical properties of promising new superconductor materials with strong application potential at high magnetic fields. Results include the following. The first strain vs. critical-current studies were made on a Chevrel-phase superconductor, PbMo/sub 6/S/sub 8/. Chevrel-phase superconductors were found to have a large strain effect, comparable in magnitude to A-15 superconductors like Nb/sub 3/Sn. Electromechanical-propertymore » measurements of an experimental liquid-tin-infiltrated Nb/sub 3/Sn conductor showed it to have an irreversible strain limit twice as large as bronze-process supercondutors and a significantly higher overall critical-current denstiy; the liquid-infiltration process thus has the potential for development of a practical Nb/sub 3/Sn conductors with both superior critical-current density and extremely good mechanical properties. Electromechanical parameters were obtained on several Nb/sub 3/Sn conductors that are candidate materials for superconducting fusion magnets, icluding conductors fabricated by the bronze, internal-tin, and jelly-roll processes. Thermal contraction data are reported on several new structural materials for superconductor sheathing and reinforcement, and a new diagnostic tool for probing the energy gap of practical superconductors has been developed using electron tunneling.« less

Thin-Film Power Transformers

NASA Technical Reports Server (NTRS)

Katti, Romney R.

1995-01-01

Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

Physics of transduction in ionic liquid-swollen Nafion membranes

NASA Astrophysics Data System (ADS)

Bennett, Matthew; Leo, Donald

2006-03-01

Ionic polymer transducers are a class of electroactive polymers that are able to generate large strains (1-5%) in response to low voltage inputs (1-5 V). Additionally, these materials generate electrical charge in response to mechanical strain and are therefore able to operate as soft, distributed sensors. Traditionally, ionic polymer transducers have been limited in their application by their hydration dependence. This work seeks to overcome this limitation by replacing the water with an ionic liquid. Ionic liquids are molten salts that exhibit very high thermal and electrochemical stability while also possessing high ionic conductivity. Results have shown that an ionic liquid-swollen ionic polymer transducer can operate for more than 250,000 cycles in air as compared to about 2,000 cycles for a water-swollen transducer. The current work examines the mechanisms of transduction in ionic liquid-swollen transducers based on Nafion polymer membranes. Specifically, the morphology and relevant ion associations within these membranes are investigated by the use of small-angle X-ray scattering (SAXS), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). These results reveal that the ionic liquid interacts with the membrane in much the same way that water does, and that the counterions of the Nafion polymer are the primary charge carriers. The results of these analyses are compared to the macroscopic transduction behavior in order to develop a model of the charge transport mechanism responsible for electromechanical coupling in these membranes.

Study on Zinc Oxide-Based Electrolytes in Low-Temperature Solid Oxide Fuel Cells.

PubMed

Xia, Chen; Qiao, Zheng; Feng, Chu; Kim, Jung-Sik; Wang, Baoyuan; Zhu, Bin

2017-12-28

Semiconducting-ionic conductors have been recently described as excellent electrolyte membranes for low-temperature operation solid oxide fuel cells (LT-SOFCs). In the present work, two new functional materials based on zinc oxide (ZnO)-a legacy material in semiconductors but exceptionally novel to solid state ionics-are developed as membranes in SOFCs for the first time. The proposed ZnO and ZnO-LCP (La/Pr doped CeO₂) electrolytes are respectively sandwiched between two Ni 0.8 Co 0.15 Al 0.05 Li-oxide (NCAL) electrodes to construct fuel cell devices. The assembled ZnO fuel cell demonstrates encouraging power outputs of 158-482 mW cm -2 and high open circuit voltages (OCVs) of 1-1.06 V at 450-550 °C, while the ZnO-LCP cell delivers significantly enhanced performance with maximum power density of 864 mW cm -2 and OCV of 1.07 V at 550 °C. The conductive properties of the materials are investigated. As a consequence, the ZnO electrolyte and ZnO-LCP composite exhibit extraordinary ionic conductivities of 0.09 and 0.156 S cm -1 at 550 °C, respectively, and the proton conductive behavior of ZnO is verified. Furthermore, performance enhancement of the ZnO-LCP cell is studied by electrochemical impedance spectroscopy (EIS), which is found to be as a result of the significantly reduced grain boundary and electrode polarization resistances. These findings indicate that ZnO is a highly promising alternative semiconducting-ionic membrane to replace the electrolyte materials for advanced LT-SOFCs, which in turn provides a new strategic pathway for the future development of electrolytes.

Memory and learning behaviors mimicked in nanogranular SiO2-based proton conductor gated oxide-based synaptic transistors

NASA Astrophysics Data System (ADS)

Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

2013-10-01

In neuroscience, signal processing, memory and learning function are established in the brain by modifying ionic fluxes in neurons and synapses. Emulation of memory and learning behaviors of biological systems by nanoscale ionic/electronic devices is highly desirable for building neuromorphic systems or even artificial neural networks. Here, novel artificial synapses based on junctionless oxide-based protonic/electronic hybrid transistors gated by nanogranular phosphorus-doped SiO2-based proton-conducting films are fabricated on glass substrates by a room-temperature process. Short-term memory (STM) and long-term memory (LTM) are mimicked by tuning the pulse gate voltage amplitude. The LTM process in such an artificial synapse is due to the proton-related interfacial electrochemical reaction. Our results are highly desirable for building future neuromorphic systems or even artificial networks via electronic elements.In neuroscience, signal processing, memory and learning function are established in the brain by modifying ionic fluxes in neurons and synapses. Emulation of memory and learning behaviors of biological systems by nanoscale ionic/electronic devices is highly desirable for building neuromorphic systems or even artificial neural networks. Here, novel artificial synapses based on junctionless oxide-based protonic/electronic hybrid transistors gated by nanogranular phosphorus-doped SiO2-based proton-conducting films are fabricated on glass substrates by a room-temperature process. Short-term memory (STM) and long-term memory (LTM) are mimicked by tuning the pulse gate voltage amplitude. The LTM process in such an artificial synapse is due to the proton-related interfacial electrochemical reaction. Our results are highly desirable for building future neuromorphic systems or even artificial networks via electronic elements. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr02987e

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

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

Lee, Jinhong; Song, Jongchan; Lee, Hongkyung

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 interfacemore » 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.« less

Novel Nd 2WO 6-type Sm 2- xA xM 1- yB yO 6- δ (A = Ca, Sr; M = Mo, W; B = Ce, Ni) mixed conductors

NASA Astrophysics Data System (ADS)

Li, Qin; Thangadurai, Venkataraman

In the present work, we have explored novel Nd 2WO 6-type structure Sm 2- xA xM 1- yB yO 6- δ (A = Ca, Sr; M = Mo, W; B = Ce, Ni) as precursor for the development of solid oxide fuel cells (SOFCs) anodes. The formation of single-phase monoclinic structure was confirmed by powder X-ray diffraction (PXRD) for the A- and B-doped Sm 2MO 6 (SMO). Samples after AC measurements under wet H 2 up to 850 °C changed from Nd 2WO 6-type structure into Sm 2MoO 5 due to the reduction of Mo VI that was confirmed by PXRD and is consistent with literature. The electrical conductivity was determined using 2-probe AC impedance and DC method and was compared with 4-probe DC method. The total electrical conductivity obtained from these two different techniques was found to vary within the experimental error over the investigated temperature of 350-650 °C. Ionic and electronic conductivity were studied using electron-blocking electrodes technique. Among the samples studied, Sm 1.8Ca 0.2MoO 6- δ exhibits total conductivity of 0.12 S cm -1 at 550 °C in wet H 2 with an activation energy of 0.06 eV. Ca-doped SMO appears to be chemically stable against reaction with YSZ electrolyte at 800 °C for 24 h in wet H 2. The ionic transference number (t i) of Sm 1.9Ca 0.1MoO 6- δ in wet H 2 at 550 °C (pO 2 = 10 -25.5 atm) was found to be about 0.012 after subtraction of electrical lead resistance from the 2-probe AC data and showed predominate electronic conductors.

Ionic contribution to the self-potential signals associated with a redox front.

PubMed

Revil, A; Trolard, F; Bourrié, G; Castermant, J; Jardani, A; Mendonça, C A

2009-10-13

In contaminant plumes or in the case of ore bodies, a source current density is produced at depth in response to the presence of a gradient of the redox potential. Two charge carriers can exist in such a medium: electrons and ions. Two contributions to the source current density are associated with these charge carriers (i) the gradient of the chemical potential of the ionic species and (ii) the gradient of the chemical potential of the electrons (i.e., the gradient of the redox potential). We ran a set of experiments in which a geobattery is generated using electrolysis reactions of a pore water solution containing iron. A DC power supply is used to impose a difference of electrical potential of 3 V between a working platinum electrode (anode) and an auxiliary platinum electrode (cathode). Both electrodes inserted into a tank filled with a well-calibrated sand infiltrated by a (0.01 mol L(-1) KCl+0.0035 mol L(-)(1) FeSO(4)) solution. After the direct current is turned off, we follow the pH, the redox potential, and the self-potential at several time intervals. The self-potential anomalies amount to a few tens of millivolts after the current is turned off and decreases over time. After several days, all the redox-active compounds produced initially by the electrolysis reactions are consumed through chemical reactions and the self-potential anomalies fall to zero. The resulting self-potential anomalies are shown to be much weaker than the self-potential anomalies observed in the presence of an electronic conductor in the laboratory or in the field. In the presence of a biotic or an abiotic electronic conductor, the self-potential anomalies can amount to a few hundred millivolts. These observations point out indirectly the potential role of bacteria forming biofilms in the transfer of electrons through sharp redox potential gradient in contaminant plumes that are rich in organic matter.

Going full circle: phase-transition thermodynamics of ionic liquids.

PubMed

Preiss, Ulrich; Verevkin, Sergey P; Koslowski, Thorsten; Krossing, Ingo

2011-05-27

We present the full enthalpic phase transition cycle for ionic liquids (ILs) as examples of non-classical salts. The cycle was closed for the lattice, solvation, dissociation, and vaporization enthalpies of 30 different ILs, relying on as much experimental data as was available. High-quality dissociation enthalpies were calculated at the G3 MP2 level. From the cycle, we could establish, for the first time, the lattice and solvation enthalpies of ILs with imidazolium ions. For vaporization, lattice, and dissociation enthalpies, we also developed new prediction methods in the course of our investigations. Here, as only single-ion values need to be calculated and the tedious optimization of an ion pair can be circumvented, the computational time is short. For the vaporization enthalpy, a very simple approach was found, using a surface term and the calculated enthalpic correction to the total gas-phase energy. For the lattice enthalpy, the most important constituent proved to be the calculated conductor-like screening model (COSMO) solvation enthalpy in the ideal electric conductor. A similar model was developed for the dissociation enthalpy. According to our assessment, the typical error of the lattice enthalpy would be 9.4 kJ mol(-1), which is less than half the deviation we get when using the (optimized) Kapustinskii equation or the recent volume-based thermodynamics (VBT) theory. In contrast, the non-optimized VBT formula gives lattice enthalpies 20 to 140 kJ mol(-1) lower than the ones we assessed in the cycle, because of the insufficient description of dispersive interactions. Our findings show that quantum-chemical calculations can greatly improve the VBT approaches, which were parameterized for simple, inorganic salts with ideally point-shaped charges. In conclusion, we suggest the term "augmented VBT", or "aVBT", to describe this kind of theoretical approach. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent development of ionic liquid stationary phases for liquid chromatography.

PubMed

Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

2015-11-13

Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrochemical-mechanical coupled modeling and parameterization of swelling and ionic transport in lithium-ion batteries

NASA Astrophysics Data System (ADS)

Sauerteig, Daniel; Hanselmann, Nina; Arzberger, Arno; Reinshagen, Holger; Ivanov, Svetlozar; Bund, Andreas

2018-02-01

The intercalation and aging induced volume changes of lithium-ion battery electrodes lead to significant mechanical pressure or volume changes on cell and module level. As the correlation between electrochemical and mechanical performance of lithium ion batteries at nano and macro scale requires a comprehensive and multidisciplinary approach, physical modeling accounting for chemical and mechanical phenomena during operation is very useful for the battery design. Since the introduced fully-coupled physical model requires proper parameterization, this work also focuses on identifying appropriate mathematical representation of compressibility as well as the ionic transport in the porous electrodes and the separator. The ionic transport is characterized by electrochemical impedance spectroscopy (EIS) using symmetric pouch cells comprising LiNi1/3Mn1/3Co1/3O2 (NMC) cathode, graphite anode and polyethylene separator. The EIS measurements are carried out at various mechanical loads. The observed decrease of the ionic conductivity reveals a significant transport limitation at high pressures. The experimentally obtained data are applied as input to the electrochemical-mechanical model of a prismatic 10 Ah cell. Our computational approach accounts intercalation induced electrode expansion, stress generation caused by mechanical boundaries, compression of the electrodes and the separator, outer expansion of the cell and finally the influence of the ionic transport within the electrolyte.

Transparent conductors based on microscale/nanoscale materials for high performance devices

NASA Astrophysics Data System (ADS)

Gao, Tongchuan

Transparent conductors are important as the top electrode for a variety of optoelectronic devices, including solar cells, light-emitting diodes (LEDs), at panel displays, and touch screens. Doped indium tin oxide (ITO) thin films are the predominant transparent conductor material. However, ITO thin films are brittle, making them unsuitable for the emerging flexible devices, and suffer from high material and processing cost. In my thesis, we developed a variety of transparent conductors toward a performance comparable with or superior to ITO thin films, with lower cost and potential for scalable manufacturing. Metal nanomesh (NM), hierarchical graphene/metal microgrid (MG), and hierarchical metal NM/MG materials were investigated. Simulation methods were used as a powerful tool to predict the transparency and sheet resistance of the transparent conductors by solving Maxwell's equations and Poisson's equation. Affordable and scalable fabrication processes were developed thereafter. Transparent conductors with over 90% transparency and less than 10 O/square sheet resistance were successfully fabricated on both rigid and flexible substrates. Durability tests, such as bending, heating and tape tests, were carried out to evaluate the robustness of the samples. Haze factor, which characterizes how blurry a transparent conductor appears, was also studied in-depth using analytical calculation and numerical simulation. We demonstrated a tunable haze factor for metal NM transparent conductors and analyzed the principle for tuning the haze factor. Plasmonic effects, excited by some transparent conductors, can lead to enhanced performance in photovoltaic devices. We systematically studied the effect of incorporating metal NM into ultrathin film silicon solar cells using numerical simulation, with the aid of optimization algorithms to reduce the optimization time. Mechanisms contributing to the enhanced performance were then identified and analyzed. Over 72% enhancement in short-circuit current-density was demonstrated by the optimal solar cell compared with 300-nm-thick Si solar cell with antireflection coating and silver back reflector.

Ion Transport via Structural Relaxations in Polymerized Ionic Liquids

NASA Astrophysics Data System (ADS)

Ganesan, Venkat; Mogurampelly, Santosh

We study the mechanisms underlying ion transport in poly(1-butyl-3-vinylimidazolium-hexafluorophosphate) polymer electrolytes. We consider polymer electrolytes of varying polymerized ionic liquid to ionic liquid (polyIL:IL) ratios and use atomistic molecular dynamics (MD) simulations to probe the dynamical and structural characteristics of the electrolyte. Our results reveal that anion diffusion along polymer backbone occurs primarily viathe formation and breaking of ion-pairs involving threepolymerized cationic monomers of twodifferent polymer chains. Moreover, we observe that the ionic diffusivities exhibit a direct correlation with the structural relaxation times of the ion-pairs and hydrogen bonds (H-bonds). These results provide new insights into the mechanisms underlying ion transport in polymerized ionic liquid electrolytes.

Effects of Cd vacancies and unconventional spin dynamics in the Dirac semimetal Cd3As2

NASA Astrophysics Data System (ADS)

Koumoulis, Dimitrios; Taylor, Robert E.; McCormick, Jeffrey; Ertas, Yavuz N.; Pan, Lei; Che, Xiaoyu; Wang, Kang L.; Bouchard, Louis-S.

2017-08-01

Cd3As2 is a Dirac semimetal that is a 3D analog of graphene. We investigated the local structure and nuclear-spin dynamics in Cd3As2 via 113Cd NMR. The wideline spectrum of the static sample at 295 K is asymmetric and its features are well described by a two-site model with the shielding parameters extracted via Herzfeld-Berger analysis of the magic-angle spinning spectrum. Surprisingly, the 113Cd spin-lattice relaxation time (T1) is extremely long (T1 = 95 s at 295 K), in stark contrast to conductors and the effects of native defects upon semiconductors; but it is similar to that of 13C in graphene (T1 = 110 s). The temperature dependence of 1/T1 revealed a complex bipartite mechanism that included a T2 power-law behavior below 330 K and a thermally activated process above 330 K. In the high-temperature regime, the Arrhenius behavior is consistent with a field-dependent Cd atomic hopping relaxation process. At low temperatures, a T2 behavior consistent with a spin-1/2 Raman-like process provides evidence of a time-dependent spin-rotation magnetic field caused by angular oscillations of internuclear vectors due to lattice vibrations. The observed mechanism does not conform to the conventional two-band model of semimetals, but is instead closer to a mechanism observed in high-Z element ionic solids with large magnetorotation constant [A. J. Vega et al., Phys. Rev. B 74, 214420 (2006)].

Physics and applications of electrochromic devices

NASA Astrophysics Data System (ADS)

Pawlicka, Agnieszka; Avellaneda, Cesar O.

2003-07-01

Solid state electrochromic devices (ECD) are of considerable technological and commercial interest because of their controllable transmission, absorption and/or reflectance. For instance, a major application of these devices is in smart windows that can regulate the solar gains of buildings and also in glare attenuation in automobile rear view mirrors. Other applications include solar cells, small and large area flat panel displays, satellite temperature control, food monitoring, and document authentication. A typical electrochromic device has a five-layer structure: GS/TC/EC/IC/IS/TC/GS, where GS is a glass substrate, TC is a transparent conductor, generally ITO (indium tin oxide) or FTO (fluorine tin oxide), EC is an electrochromic coating, IC is an ion conductor (solid or liquid electrolyte) and IS is an ion storage coating. Generally, the EC and IS layers are deposited separately on the TC coatings and then jointed with the IC and sealed. The EC and IS are thin films that can be deposited by sputtering, CVD, sol-gel precursors, etc. There are different kinds of organic, inorganic and organic-inorganic films that can be used to make electrochromic devices. Thin electrochromic films can be: WO3, Nb2O5, Nb2O5:Li+ or Nb2O5-TiO2 coatings, ions storage films: CeO2-TiO2, CeO2-ZrO2 or CeO2-TiO2-ZrO2 and electrolytes like Organically Modified Electrolytes (Ormolytes) or polymeric films also based on natural polymers like starch or cellulose. These last are very interesting due to their high ionic conductivity, high transparency and good mechanical properties. This paper describes construction and properties of different thin oxide and polymeric films and also shows the optical response of an all sol-gel electrochromic device with WO3/Ormolyte/CeO2-TiO2 configuration.

PREFACE: MEM07: The 5th Annual Workshop on Mechanical and Electromagnetic Properties of Composite Superconductors (Princeton, NJ, USA, 21 24 August 2007)

NASA Astrophysics Data System (ADS)

Larbalestier, D. C.; Osamura, K.; Hampshire, D. P.

2008-05-01

MEM07 was the 5th international workshop concentrating on the mechanical and electrical properties of composite superconductors, which are the technological conductor forms from which practical superconducting devices are made. Such superconducting conductors respond to important challenges we currently face, especially those concerned with the proper management of the world's energy resources. Superconductivity provides a means to address the challenges in the generation, transmission and distribution, and use of energy. For energy generation, the ITER Fusion Tokomak (now underway in France) provides exciting new challenges for the whole superconductivity community, due to the enormous size and strong fields of the plasma confinement superconducting magnets that will form the largest and most powerful superconducting machine yet built. Significant attention was paid at MEM07 to the modeling, characterization, testing and validation of the high-amperage Nb3Sn cable-in-conduit conductors needed for ITER. As for electric energy industry uses, there was much discussion of both first generation (Bi,Pb)2Sr2Ca2Cu3Ox conductors and the rapidly emerging second generation coated conductors made from YBa2Cu37-x. High-performing, affordable conductors of these materials are vital for large capacity transmission cables, energy storage systems, fault current limiters, generators and motors—many prototypes of which are being pursued in technologically advanced countries. There is a broad consensus that the prototype stage for high-current-high-field superconducting applications is nearing its end and that large scale applications are technologically feasible. However full industrialization of large-scale superconducting technologies in electric utility applications will benefit from continuous improvement in critical current, lower ac loss, higher strength and other vital conductor properties. The establishment of optimal procedures for the system design accompanying scale-up is a second vital task. As system design is dependent on material development, there is a critical need to study the key issues in developing high performance superconducting materials. The emphases of MEM07 were The mechanical properties of superconductors including the influence of stress and strain on the critical current of practical conductors including YBCO and ReBCO coated conductors, BSCCO tapes, MgB2 wires and Nb3Sn filamentary conductors. The intrinsic strain effects on critical current density in Nb3Sn, YBCO, BSCCO and MgB2. Recent advances in critical current, the mechanical properties and the reduction in ac losses of HTS tapes and wires. The compositional and microstructural dependence of E-J characteristics and explanations based on flux pinning, grain boundary weak-links and other mechanisms. Standardized test-methods: international cooperative research work to establish test methods for assessing the mechano-electromagnetic properties of superconductors based on the activities of IEC/TC90 and VAMAS/TWA-16. More than 60 researchers from more than 12 countries attended the MEM07 workshop, and about 40 presentations were made. A small selection of papers (15) from the workshop are included in this special issue of Superconductor Science and Technology. Taken together with papers published at earlier MEM meetings, this issue provides an updated view of some of the current state-of-the-art research in the mechano-electromagnetic properties of composite superconductors. The workshop was organized under the activities of the NEDO Grant Project (Applied Superconductivity, 2004EA004) and VAMAS/TWA-16. The meeting was organized by a committee composed of David Larbalestier (Conference Chair) aided by MEM05 and MEM06 Conference Chairs Kozo Osamura (Research Institute for Applied Sciences, Kyoto, Japan), Damian Hampshire (Durham University, UK) and Arman Nyilas (CEME). The Program Committee was composed of Ettore Salpietro (European Fusion Development Agreement), Neil Mitchell (ITER), Kozo Osamura, Damian Hampshire and Arman Nyilas. We express our great thanks to all those whose efforts were key in organizing the meeting, with very special thanks to our Meeting Planner Kate Liu who organized matters large and small with discretion and great efficiency.

An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq−1)

PubMed Central

Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K.; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

2016-01-01

Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ∼1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq−1), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ∼30 dB attenuation up to 18 GHz was achieved. PMID:27991517

An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq-1).

PubMed

Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

2016-12-19

Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ∼1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO 2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq -1 ), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ∼30 dB attenuation up to 18 GHz was achieved.

Electroactive Ionic Soft Actuators with Monolithically Integrated Gold Nanocomposite Electrodes.

PubMed

Yan, Yunsong; Santaniello, Tommaso; Bettini, Luca Giacomo; Minnai, Chloé; Bellacicca, Andrea; Porotti, Riccardo; Denti, Ilaria; Faraone, Gabriele; Merlini, Marco; Lenardi, Cristina; Milani, Paolo

2017-06-01

Electroactive ionic gel/metal nanocomposites are produced by implanting supersonically accelerated neutral gold nanoparticles into a novel chemically crosslinked ion conductive soft polymer. The ionic gel consists of chemically crosslinked poly(acrylic acid) and polyacrylonitrile networks, blended with halloysite nanoclays and imidazolium-based ionic liquid. The material exhibits mechanical properties similar to that of elastomers (Young's modulus ≈ 0.35 MPa) together with high ionic conductivity. The fabrication of thin (≈100 nm thick) nanostructured compliant electrodes by means of supersonic cluster beam implantation (SCBI) does not significantly alter the mechanical properties of the soft polymer and provides controlled electrical properties and large surface area for ions storage. SCBI is cost effective and suitable for the scaleup manufacturing of electroactive soft actuators. This study reports the high-strain electromechanical actuation performance of the novel ionic gel/metal nanocomposites in a low-voltage regime (from 0.1 to 5 V), with long-term stability up to 76 000 cycles with no electrode delamination or deterioration. The observed behavior is due to both the intrinsic features of the ionic gel (elasticity and ionic transport capability) and the electrical and morphological features of the electrodes, providing low specific resistance (<100 Ω cm -2 ), high electrochemical capacitance (≈mF g -1 ), and minimal mechanical stress at the polymer/metal composite interface upon deformation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural and Na-ion conduction characteristics of Na 3PS xSe 4–x

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

Bo, Shou -Hang; Wang, Yan; Ceder, Gerbrand

The recent discovery of the isostructrual cubic Na 3PS 4 and Na 3PSe 4 as fast Na-ion conductors provided a general structural framework for the exploration of new sodium superionic conductors. In this work, we systematically investigated the structures and ionic conduction characteristics of a series of compounds with the general chemical formula of Na 3PS xSe 4–x. Synthesis of Na 3PS 4 under different conditions (e.g., temperature, reaction vessel, mass of the precursors) reveals the reactivity of the precursors with the reaction tubes, producing different polymorphs. X-ray diffraction studies on the solid solution phases Na 3PS xSe 4–x identifiedmore » a tetragonal-to-cubic phase transition with increasing Se concentration. This observation is consistent with the computed stability of the tetragonal and cubic polymorphs, where the energy difference between the two polymorphs becomes very close to zero in Se-rich compositions. Furthermore, ab initio molecular dynamic simulations suggest that the fast Na-ion conduction in Na 3PS xSe 4–x may not be causally related with the symmetry or the composition of these phases. The formation of defects, instead, enables fast Na-ion conduction in this class of materials.« less

Structural and Na-ion conduction characteristics of Na 3 PS x Se 4-x

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

Bo, Shou-Hang; Wang, Yan; Ceder, Gerbrand

The recent discovery of the isostructrual cubic Na 3PS 4 and Na 3PSe 4 as fast Na-ion conductors provided a general structural framework for the exploration of new sodium superionic conductors. In this work, we systematically investigated the structures and ionic conduction characteristics of a series of compounds with the general chemical formula of Na 3PS xSe 4-x. Synthesis of Na 3PS 4 under different conditions (e.g., temperature, reaction vessel, mass of the precursors) reveals the reactivity of the precursors with the reaction tubes, producing different polymorphs. X-ray diffraction studies on the solid solution phases Na 3PS xSe 4-x more » identified a tetragonal-to-cubic phase transition with increasing Se concentration. This observation is consistent with the computed stability of the tetragonal and cubic polymorphs, where the energy difference between the two polymorphs becomes very close to zero in Se-rich compositions. Furthermore, ab initio molecular dynamic simulations suggest that the fast Na-ion conduction in Na 3PS xSe 4-x may not be causally related with the symmetry or the composition of these phases. The formation of defects, instead, enables fast Na-ion conduction in this class of materials.« less

Fluorite Ce0.8Sm0.2O2- δ porous layer coating to enhance the oxygen permeation behavior of a BaCo0.7Fe0.2Nb0.1O3- δ mixed conductor

NASA Astrophysics Data System (ADS)

Wang, Tai-he; Song, Wei-jia; Li, Rong; Zhen, Qiang

2016-06-01

Fluorite Ce0.8Sm0.2O2- δ (SDC) nanopowder with a crystallite size of 15 nm was synthesized by a co-precipitation method. An SDC porous layer was coated onto a BaCo0.7Fe0.2Nb0.1O3- δ (BCFN) mixed conductor to improve its oxygen transport behavior. The results show that the SDC-coated BCFN membrane exhibits a remarkably higher oxygen permeation flux ({J_{{O_2}}}) than the uncoated BCFN in the partial oxidation of coke oven gas (COG). The maximum {J_{{O_2}}} value of the SDC-coated BCFN is 18.28 mL·min-1·cm-2 under a COG/air flux of 177 mL·min-1/353 mL·min-1 at 875°C when the thickness of the BCFN membrane is 1 mm; this {J_{{O_2}}} value is 23% higher than that of the uncoated BCFN membrane. This enhancement is likely because of the higher oxygen ionic conductivity of SDC, which supplies oxygen vacancies and accelerates oxygen exchange on the membrane/coating layer/gas three-phase boundary.

A Crystal-Physical Model of Electrotransfer in the Superionic Conductor Pb1 - x Sc x F2 + x ( x = 0.1)

NASA Astrophysics Data System (ADS)

Sorokin, N. I.

2018-04-01

The frequency (ν = 10-1-107 Hz) dependences of electrical conductivity σ(ν) of single crystals of superionic conductor Pb0.9Sc0.1F2.1 (10 mol % ScF3) with fluorite type structure (CaF2) in the temperature range 153-410 K have been investigated. The static bulk conductivity σ dc =1.5 × 10-4 S/cm and average hopping frequency ν h = 1.5 × 107 Hz of charge carriers (mobile ions F-) at room temperature (293 K) have been defined from the σ dc (ν) experimental curves. Enthalpies of thermoactivated processes of ionic conductivity σ dc ( T) (Δ H σ = 0.393 ± 0.005 eV) and dielectric relaxation ν h ( T) (Δ H h = 0.37 ± 0.03 eV) coincide within their errors. A crystal-physical model of fluorine-ion transport in a Pb0.9Sc0.1F2.1 crystal lattice has been proposed. The characteristic parameters of charge carriers have been calculated: concentration n mob = 2.0 × 1021 cm-3, the distance of the hopping d ≈ 0.5 nm and mobility μmob = 4.5 × 10-7 cm2/s V (293 K).

Origin of high Li⁺ conduction in doped Li₇La₃Zr₂O₁₂ garnets

DOE PAGES

Chen, Yan; Rangasamy, Ezhiylmurugan; Liang, Chengdu; ...

2015-08-06

Substitution of a native ion in the crystals with a foreign ion that differs in valence ( aliovalent doping) has been widely attempted to upgrade solid-state ionic conductors for various charge carriers including O²⁻, H⁺, Li⁺, Na⁺, etc. The doping helps promote the high-conductive framework and dredge the tunnel for fast ion transport. The garnet-type Li₇La₃Zr₂O₁₂ (LLZO) is a fast Li⁺ solid conductor, which received much attention as an electrolyte candidate for all-solid-state lithium ion batteries, showing great potential to offer high energy density and minimize battery safety concerns to meet extensive applications in large energy storage systems such asmore » those for electric vehicles and aerospace. In the Li-stuffed garnet framework of LLZO, the 3D pathway formed by the incompletely occupied tetrahedral sites bridged by a single octahedron enables the superior Li⁺ conductivity. For optimal performance, many aliovalent-doping efforts have been made throughout metal elements (Al³⁺, Ta⁵⁺) and metalloid elements (Ga³⁺, Te⁶⁺) in the periodic table with various valences to stabilize the high-conductive phase and increase the Li vacancy concentration.« less

Streaming current magnetic fields in a charged nanopore

PubMed Central

Mansouri, Abraham; Taheri, Peyman; Kostiuk, Larry W.

2016-01-01

Magnetic fields induced by currents created in pressure driven flows inside a solid-state charged nanopore were modeled by numerically solving a system of steady state continuum partial differential equations, i.e., Poisson, Nernst-Planck, Ampere and Navier-Stokes equations (PNPANS). This analysis was based on non-dimensional transport governing equations that were scaled using Debye length as the characteristic length scale, and applied to a finite length cylindrical nano-channel. The comparison of numerical and analytical studies shows an excellent agreement and verified the magnetic fields density both inside and outside the nanopore. The radially non-uniform currents resulted in highly non-uniform magnetic fields within the nanopore that decay as 1/r outside the nanopore. It is worth noting that for either streaming currents or streaming potential cases, the maximum magnetic field occurred inside the pore in the vicinity of nanopore wall, as opposed to a cylindrical conductor that carries a steady electric current where the maximum magnetic fields occur at the perimeter of conductor. Based on these results, it is suggested and envisaged that non-invasive external magnetic fields readouts generated by streaming/ionic currents may be viewed as secondary electronic signatures of biomolecules to complement and enhance current DNA nanopore sequencing techniques. PMID:27833119

High-throughput design and optimization of fast lithium ion conductors by the combination of bond-valence method and density functional theory

NASA Astrophysics Data System (ADS)

Xiao, Ruijuan; Li, Hong; Chen, Liquan

2015-09-01

Looking for solid state electrolytes with fast lithium ion conduction is an important prerequisite for developing all-solid-state lithium secondary batteries. By combining the simulation techniques in different levels of accuracy, e.g. the bond-valence (BV) method and the density functional theory (DFT), a high-throughput design and optimization scheme is proposed for searching fast lithium ion conductors as candidate solid state electrolytes for lithium rechargeable batteries. The screening from more than 1000 compounds is performed through BV-based method, and the ability to predict reliable tendency of the Li+ migration energy barriers is confirmed by comparing with the results from DFT calculations. β-Li3PS4 is taken as a model system to demonstrate the application of this combination method in optimizing properties of solid electrolytes. By employing the high-throughput DFT simulations to more than 200 structures of the doping derivatives of β-Li3PS4, the effects of doping on the ionic conductivities in this material are predicted by the BV calculations. The O-doping scheme is proposed as a promising way to improve the kinetic properties of this materials, and the validity of the optimization is proved by the first-principles molecular dynamics (FPMD) simulations.

Structural and Na-ion conduction characteristics of Na 3PS xSe 4–x

DOE PAGES

Bo, Shou -Hang; Wang, Yan; Ceder, Gerbrand

2016-05-19

The recent discovery of the isostructrual cubic Na 3PS 4 and Na 3PSe 4 as fast Na-ion conductors provided a general structural framework for the exploration of new sodium superionic conductors. In this work, we systematically investigated the structures and ionic conduction characteristics of a series of compounds with the general chemical formula of Na 3PS xSe 4–x. Synthesis of Na 3PS 4 under different conditions (e.g., temperature, reaction vessel, mass of the precursors) reveals the reactivity of the precursors with the reaction tubes, producing different polymorphs. X-ray diffraction studies on the solid solution phases Na 3PS xSe 4–x identifiedmore » a tetragonal-to-cubic phase transition with increasing Se concentration. This observation is consistent with the computed stability of the tetragonal and cubic polymorphs, where the energy difference between the two polymorphs becomes very close to zero in Se-rich compositions. Furthermore, ab initio molecular dynamic simulations suggest that the fast Na-ion conduction in Na 3PS xSe 4–x may not be causally related with the symmetry or the composition of these phases. The formation of defects, instead, enables fast Na-ion conduction in this class of materials.« less

Double perovskite cathodes for proton-conducting ceramic fuel cells: are they triple mixed ionic electronic conductors?

PubMed Central

Téllez Lozano, Helena; Druce, John; Cooper, Samuel J.; Kilner, John A.

2017-01-01

Abstract 18O and 2H diffusion has been investigated at a temperature of 300 °C in the double perovskite material PrBaCo2O5+δ (PBCO) in flowing air containing 200 mbar of 2H2 16O. Secondary ion mass spectrometry (SIMS) depth profiling of exchanged ceramics has shown PBCO still retains significant oxygen diffusivity (~1.3 × 10−11 cm2s−1) at this temperature and that the presence of water (2H2 16O), gives rise to an enhancement of the surface exchange rate over that in pure oxygen by a factor of ~3. The 2H distribution, as inferred from the 2H2 16O− SIMS signal, shows an apparent depth profile which could be interpreted as 2H diffusion. However, examination of the 3-D distribution of the signal shows it to be nonhomogeneous and probably related to the presence of hydrated layers in the interior walls of pores and is not due to proton diffusion. This suggests that PBCO acts mainly as an oxygen ion mixed conductor when used in PCFC devices, although the presence of a small amount of protonic conductivity cannot be discounted in these materials. PMID:29383047

Influence of Zwitterions on Thermomechanical Properties and Morphology of Acrylic Copolymers: Implications for Electroactive Applications

DTIC Science & Technology

2011-09-30

transducers from branched sulfonated polysulfones.7 The mechanical strength of the membranes drastically decreased upon introduction of ionic liquids to... liquids ,8 and zwitterionomers maintained mechanical strengths upon swelling with 10 wt % ionic liquid . Zwitterions are chargedmolecules that contain...water purification5 to biotechnology.6 A unique combination of physical properties of ionomeric membranes is the ionic con- ductivity of lowmolar mass

Lithium1.3Aluminum0.3Titanium1.7Phosphate as a solid state Li-ion conductor: Issues with microcracking and stability in aqueous solutions

NASA Astrophysics Data System (ADS)

Jackman, Spencer D.

Lithium aluminum titanium phosphate (LATP) with formula Li1.3Al0.3Ti1.7(PO4)3 was analyzed and tested to better understand its applicability as a solid state ion conducting ceramic material for electrochemical applications. Sintered samples were obtained from Ceramatec, Inc. in Salt Lake City and characterized in terms of density, phase-purity, fracture toughness, Young's modulus, thermal expansion behavior, mechanical strength, a.c. and d.c. ionic conductivity, and susceptibility to static and electrochemical corrosion in aqueous Li salt solutions. It was shown that LATP is prone to microcrack generation because of high thermal expansion anisotropy. A.c. impedance spectra of high-purity LATP of varying grain sizes showed that microcracking had a negative impact on the ionic conduction of Li along grain boundaries, with fine-grained (1.7±0.7 µm) LATP having twice the ionic conductivity of the same purity of coarse-grained (4.8±1.9 µm) LATP at 50°C. LATP with detectible secondary phases had lower ionic conductivity for similar grain sizes, as would be expected. The Young's modulus of fine-grained LATP was measured to be 115 GPa, and the highest biaxial strength was 191±11 MPa when tested in mineral oil, 144±13 MPa as measured in air, and 26±7 MPa after exposure to deionized water, suggesting that LATP undergoes stress-corrosion cracking. After exposure to LiOH, the strength was 76±19 MPa. This decrease in strength was observed despite there being no measureable change in a.c. impedance spectra, X-ray diffraction, or sample mass, suggesting phosphate glasses at grain boundaries. The chemical and electrochemical stability of high-purity LATP in aqueous electrochemical cells was evaluated using LiOH, LiCl, LiNO3, and LiCOOCH3 salts as the Li source. LATP was found to be most stable between pH 8-9, with the longest cell operating continuously at 25 mA cm-2 for 625 hours at 40°C in LiCOOCH3. At pH values outside of the 7-10 range, eventual membrane degradation was observed in all aqueous systems under electrochemical conditions. While LATP was surprisingly resistant to static corrosion in a hot, aqueous LiOH solution, electrochemical degradation was observed at the cathode due to subsurface pitting. Strength measurements were more instructive than impedance measurements in detecting this degradation.

Finite element analysis on deformation of stretchable electronic interconnect substrate using polydimethylsiloxanes (PDMS)

NASA Astrophysics Data System (ADS)

Roslan, M. F.; Shaffiar, N. M.; Khairusshima, M. K. N.; Sharifah, I. S. S.

2018-01-01

Over the years, the technology of electronic industry has growth tremendously. Open ended research on how to make a better concept of electronic circuit is ongoing especially on the stretchable electronic devices. There are many designs to achieve stretchability in electronic circuits. The problem occurs when deformation applied to the stretchable electronic circuit, it cannot maintain its functionality. Fracture may happen on the conductor. In this research, the study on deformation of stretchable electronic interconnects substrate using Polydimethlysiloxanes is carried out. The purpose of this research are to study the axial deformation occur, to determine the optimum shape of the conductor designs (horseshoe, rectangular and u-shape design) for the stretchable electronic interconnect and to compare the mechanical properties of Polydimethlysiloxanes (PDMS) with Polyurethane (PU) using Finite Element Analysis (FEA). The simulation was done on the FE model of the stretchable circuit with dimension of 2.4 X 2.4 X 0.5 mm. The stretching of the FE model was simulated with the range of elongation at 10, 20 and 30 percent from its original length in order to find the strain value for all three of the conductor designs. The best conductor design is used to simulate with different types of substrate (PDMS and PU). From the simulation result, Horseshoe design record the lowest strain value for each elongation, followed by rectangular and U-shape design. Thus, Horseshoe is considered as the optimum design for the conductor compared to the other two designs. From the result also, it shows that PDMS substrate will offer more maximum allowable stretchability compared to PU substrates. Thus PDMS is considered as a better substrate compare to PU. PDMS is a good material to replace PU since it can perform under tension much better mechanically.

LiBi{sub 3}S{sub 5}—A lithium bismuth sulfide with strong cation disorder

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

Nakhal, Suliman; Wiedemann, Dennis, E-mail: dennis.wiedemann@chem.tu-berlin.de; Stanje, Bernhard

Among chalcogenide semiconductors for thermoelectric applications, alkali-metal bismuth compounds occur in many complex compositions favorable for high performance. Although LiBi{sub 3}S{sub 5} had been announced in 1977, the potential 1D lithium-ion conductor has hitherto eluded selective synthesis and structure determination. In this study, we present a solid-state route to phase-pure LiBi{sub 3}S{sub 5} powder starting from LiBiS{sub 2} and Bi{sub 2}S{sub 3}. Neutron diffractograms and lithium NMR spectra reveal its crystal structure to be a cation-disordered variety of the AgBi{sub 3}S{sub 5} type (synthetic pavonite; monoclinic, C2/m). Topological analyses and lithium NMR relaxometry suggest that correlated lithium-ion diffusion with activationmore » energies up to 0.66(2) eV occurs along the channels in b direction including tetrahedral voids. Because of cation disorder, immobile bismuth(III) ions clog these pathways, making LiBi{sub 3}S{sub 5} a moderate to poor ionic conductor. The synthesis route reported is nonetheless promising for new lithium bismuth sulfides with, possibly ordered, structure types of the pavonite homologous series. - Graphical abstract: Phase-pure LiBi{sub 3}S{sub 5} has been synthesized and shown to crystallize in cation-disordered variety of the AgBi{sub 3}S{sub 5} type (synthetic pavonite, C2/m) using neutron diffractometry. Topological analyses and NMR relaxometry suggest that immobile Bi{sup 3+} ions clog migration channels along b, making the material a poor lithium conductor. Display Omitted - Highlights: • Phase-pure LiBi{sub 3}S{sub 5} has been synthesized using a promising solid-state route. • LiBi{sub 3}S{sub 5} crystallizes in a cation-disordered variant of the AgBi{sub 3}S{sub 5} type. • Topological analyses suggest lithium diffusion in channels along b. • NMR relaxometry finds activation energies of diffusion as high as 0.66(2) eV. • Because of disorder, LiBi{sub 3}S{sub 5} is a moderate to poor lithium-ion conductor.« less

The radiation chemistry of ionic liquids: A review

DOE PAGES

Mincher, Bruce J.; Wishart, James F.

2014-07-03

Ionic liquids have received increasing attention as media for radiochemical separations. Recent literature includes examinations of the efficiencies and mechanisms of the solvent extraction of lanthanides, actinides and fission products into ionic liquid solutions. For radiochemical applications, including as replacement solvents for nuclear fuel reprocessing, a thorough understanding of the radiation chemistry of ionic liquids will be required. Such an understanding can be achieved based on a combination of steady-state radiolysis experiments coupled with post-irradiation product identification and pulse-radiolysis experiments to acquire kinetic information. These techniques allow for the elucidation of radiolytic mechanisms. This contribution reviews the current ionic liquidmore » radiation chemistry literature as it affects separations, with these considerations in mind.« less

Polymer stability and function for electrolyte and mixed conductor applications

NASA Astrophysics Data System (ADS)

Hammond, Paula; Davis, Nicole; Liu, David; Amanchukwu, Chibueze; Lewis, Nate; Shao-Horn, Yang

2015-03-01

Polymers exhibit a number of attractive properties as solid state electrolytes for electrochemical energy devices, including the light weight, flexibility, low cost and adaptive transport properties that polymeric materials can exhibit. For a number of applications, mixed ionic and electronic conducting materials are of interest to achieve transport of electrons and holes or ions within an electrode or at the electrode-electrolyte interface (e.g. aqueous batteries, solar water splitting, lithium battery electrode). Using layer-by-layer assembly, a mode of alternating adsorption of charged or complementary hydrogen bonding group, we can design composite thin films that contain bicontinuous networks of electronically and ionically conducting polymers. We have found that manipulation of salt concentration and the use of divalent ions during assembly can significantly enhance the number of free acid anions available for ion hopping. Unfortunately, for certain electrochemical applications, polymer stability is a true challenge. In separate studies, we have been investigating macromolecular systems that may provide acceptable ion transport properties, but withstand the harsh oxidative environment of lithium air systems. An investigation of different polymeric materials commonly examined for electrochemical applications provides insight into polymer design for these kinds of environments. NSF Center for Chemical Innovation, NDSEG Fellowship and Samsung Corporation.

Dimensional control of defect dynamics in perovskite oxide superlattices

NASA Astrophysics Data System (ADS)

Bredeson, Isaac; Zhang, Lipeng; Kent, P. R. C.; Cooper, Valentino R.; Xu, Haixuan

2018-03-01

Point defects play a critical role in the structural, physical, and interfacial properties of perovskite oxide superlattices. However, understanding of the fundamental properties of point defects in superlattices, especially their transport properties, is rather limited. Here, we report predictions of the stability and dynamics of oxygen vacancies in SrTi O3/PbTi O3 oxide superlattices using first-principles calculations in combination with the kinetic Monte Carlo method. By varying the stacking period, i.e., changing of n in n STO /n PTO , we discover a crossover from three-dimensional diffusion to primarily two-dimensional planar diffusion. Such planar diffusion may lead to novel designs of ionic conductors. We show that the dominant vacancy position may vary in the superlattices, depending on the superlattice structure and stacking period, contradicting the common assumption that point defects reside at interfaces. Moreover, we predict a significant increase in room-temperature ionic conductivity for 3STO/3PTO relative to the bulk phases. Considering the variety of cations that can be accommodated in perovskite superlattices and the potential mismatch of spin, charge, and orbitals at the interfaces, this paper identifies a pathway to control defect dynamics for technological applications.

Driving mechanisms of ionic polymer actuators having electric double layer capacitor structures.

PubMed

Imaizumi, Satoru; Kato, Yuichi; Kokubo, Hisashi; Watanabe, Masayoshi

2012-04-26

Two solid polymer electrolytes, composed of a polyether-segmented polyurethaneurea (PEUU) and either a lithium salt (lithium bis(trifluoromethanesulfonyl)amide: Li[NTf2]) or a nonvolatile ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide: [C2mim][NTf2]), were prepared in order to utilize them as ionic polymer actuators. These salts were preferentially dissolved in the polyether phases. The ionic transport mechanism of the polyethers was discussed in terms of the diffusion coefficients and ionic transference numbers of the incorporated ions, which were estimated by means of pulsed-field gradient spin-echo (PGSE) NMR. There was a distinct difference in the ionic transport properties of each polymer electrolyte owing to the difference in the magnitude of interactions between the cations and the polyether. The anionic diffusion coefficient was much faster than that of the cation in the polyether/Li[NTf2] electrolyte, whereas the cation diffused faster than the anion in the polyether/[C2mim][NTf2] electrolyte. Ionic polymer actuators, which have a solid-state electric-double-layer-capacitor (EDLC) structure, were prepared using these polymer electrolyte membranes and ubiquitous carbon materials such as activated carbon and acetylene black. On the basis of the difference in the motional direction of each actuator against applied voltages, a simple model of the actuation mechanisms was proposed by taking the difference in ionic transport properties into consideration. This model discriminated the behavior of the actuators in terms of the products of transference numbers and ionic volumes. The experimentally observed behavior of the actuators was successfully explained by this model.

Mutual capacitance of liquid conductors in deformable tactile sensing arrays

NASA Astrophysics Data System (ADS)

Li, Bin; Fontecchio, Adam K.; Visell, Yon

2016-01-01

Advances in highly deformable electronics are needed in order to enable emerging categories of soft computing devices ranging from wearable electronics, to medical devices, and soft robotic components. The combination of highly elastic substrates with intrinsically stretchable conductors holds the promise of enabling electronic sensors that can conform to curved objects, reconfigurable displays, or soft biological tissues, including the skin. Here, we contribute sensing principles for tactile (mechanical image) sensors based on very low modulus polymer substrates with embedded liquid metal microfluidic arrays. The sensors are fabricated using a single-step casting method that utilizes fine nylon filaments to produce arrays of cylindrical channels on two layers. The liquid metal (gallium indium alloy) conductors that fill these channels readily adopt the shape of the embedding membrane, yielding levels of deformability greater than 400%, due to the use of soft polymer substrates. We modeled the sensor performance using electrostatic theory and continuum mechanics, yielding excellent agreement with experiments. Using a matrix-addressed capacitance measurement technique, we are able to resolve strain distributions with millimeter resolution over areas of several square centimeters.

Mutual capacitance of liquid conductors in deformable tactile sensing arrays

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

Li, Bin; Fontecchio, Adam K.; Visell, Yon

2016-01-04

Advances in highly deformable electronics are needed in order to enable emerging categories of soft computing devices ranging from wearable electronics, to medical devices, and soft robotic components. The combination of highly elastic substrates with intrinsically stretchable conductors holds the promise of enabling electronic sensors that can conform to curved objects, reconfigurable displays, or soft biological tissues, including the skin. Here, we contribute sensing principles for tactile (mechanical image) sensors based on very low modulus polymer substrates with embedded liquid metal microfluidic arrays. The sensors are fabricated using a single-step casting method that utilizes fine nylon filaments to produce arraysmore » of cylindrical channels on two layers. The liquid metal (gallium indium alloy) conductors that fill these channels readily adopt the shape of the embedding membrane, yielding levels of deformability greater than 400%, due to the use of soft polymer substrates. We modeled the sensor performance using electrostatic theory and continuum mechanics, yielding excellent agreement with experiments. Using a matrix-addressed capacitance measurement technique, we are able to resolve strain distributions with millimeter resolution over areas of several square centimeters.« less

Sensor apparatus using an electrochemical cell

DOEpatents

Thakur, Mrinal

2002-01-01

A novel technology for sensing mechanical quantities such as force, stress, strain, pressure and acceleration has been invented. This technology is based on a change in the electrochemically generated voltage (electromotive force) with application of force, stress, strain, pressure or acceleration. The change in the voltage is due to a change in the internal resistance of the electrochemical cell with a change in the relative position or orientation of the electrodes (anode and cathode) in the cell. The signal to be detected (e.g. force, stress, strain, pressure or acceleration) is applied to one of the electrodes to cause a change in the relative position or orientation between the electrodes. Various materials, solid, semisolid, gel, paste or liquid can be utilized as the electrolyte. The electrolyte must be an ion conductor. The examples of solid electrolytes include specific polymer conductors, polymer composites, ion conducting glasses and ceramics. The electrodes are made of conductors such as metals with dissimilar electronegativities. Significantly enhanced sensitivities, up to three orders of magnitude higher than that of comparable commercial sensors, are obtained. The materials are substantially less expensive than commercially used materials for mechanical sensors.

Electromagnetic studies in the Fennoscandian Shield—electrical conductivity of Precambrian crust

NASA Astrophysics Data System (ADS)

Korja, T.; Hjelt, S.-E.

1993-12-01

Electromagnetic (EM) investigations of the 1980s in the Fennoscandian (Baltic) Shield produced an unique and unified EM data set. Studies include regional investigations by the magnetovariational (MV) method with large lateral sampling distance, investigations of anomalous conductivity structures by magnetotelluric (MT) soundings and other (EM) and electrical methods (audio MT soundings, d.c. dipole-dipole and VLF resistivity profilings) with shorter sampling distance, and studies of the near-surface conductivity by airborne EM surveys. The variety of methods provide an ability to map efficiently crustal conductivity structures from a regional scale of hundreds of kilometres down to local details of some metres in the anomalous structures. The Precambrian of the Fennoscandian Shield is characterized by roughly NW-SE-directed elongated belts of conductors which separate more resistive crustal blocks. The latter serve as transparent windows through which to probe deep electrical structure and belts of conductors as tectonic markers of ancient orogenic zones including (1) the Kittilä-Vetrenny Poyas conductor, (2) the Lapland Granulite Belt and Inari-Pechenga-Imandra-Varzuga conductors, (3) the Archaean-Proterozoic boundary conductor and (4) the Southern Finland Conductor. The conductive belts—orogenic conductors—indicate places where crustal masses collided and were finally sealed together. Enhanced conductivity in the orogenic conductors is caused primarily by an electronic conducting mechanism in graphite- and sulphide-bearing metasedimentary rocks. Estimations of the lower-crustal conductivity indicate a laterally heterogeneous lower crust in the Fennoscandian Shield. Archaean lower crust seems to be in general more resistive than the Early Proterozoic lower crust of the Karelian and Svecofennian Domains. The lower crust in the southwestern part of the Svecofennian Domain and in the Sveconorwegian Domain seems to be more resistive than in the central part of the Svecofennian Domain.

A novel eddy current damper: theory and experiment

NASA Astrophysics Data System (ADS)

Ebrahimi, Babak; Khamesee, Mir Behrad; Golnaraghi, Farid

2009-04-01

A novel eddy current damper is developed and its damping characteristics are studied analytically and experimentally. The proposed eddy current damper consists of a conductor as an outer tube, and an array of axially magnetized ring-shaped permanent magnets separated by iron pole pieces as a mover. The relative movement of the magnets and the conductor causes the conductor to undergo motional eddy currents. Since the eddy currents produce a repulsive force that is proportional to the velocity of the conductor, the moving magnet and the conductor behave as a viscous damper. The eddy current generation causes the vibration to dissipate through the Joule heating generated in the conductor part. An accurate, analytical model of the system is obtained by applying electromagnetic theory to estimate the damping properties of the proposed eddy current damper. A prototype eddy current damper is fabricated, and experiments are carried out to verify the accuracy of the theoretical model. The experimental test bed consists of a one-degree-of-freedom vibration isolation system and is used for the frequency and transient time response analysis of the system. The eddy current damper model has a 0.1 m s-2 (4.8%) RMS error in the estimation of the mass acceleration. A damping coefficient as high as 53 Ns m-1 is achievable with the fabricated prototype. This novel eddy current damper is an oil-free, inexpensive damper that is applicable in various vibration isolation systems such as precision machinery, micro-mechanical suspension systems and structure vibration isolation.

Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots.

PubMed

Keller, A J; Lim, J S; Sánchez, David; López, Rosa; Amasha, S; Katine, J A; Shtrikman, Hadas; Goldhaber-Gordon, D

2016-08-05

In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.

Pulmonary function abnormalities associated with exposure to automobile exhaust in a diesel bus garage and roads.

PubMed

Chattopadhyay, B P; Alam, J; Roychowdhury, A

2003-01-01

In Kolkata city the road transports are maintained by private and Government organization. A major work force belonged to the State Transport Corporation (KSTC), Government of West-Bengal. The pollution caused by these vehicles affects the workers health and caused different types of respiratory problems. This study was undertaken to assess the pulmonary function status of these workers. City KSTC garage workers were investigated and categorically divided into two group: garage mechanics and the (2) those transporting the passengers (drivers and conductors). Vital capacity (VC), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) were recorded by Spirovit-SP-10 (Schiller Ltd, Switzerland) and Wright's Peak Flow Meter (UK) on 236 workers. The different flow volumes, FEV(1), FEV(1%), and flow rates, FEF(02-121), FEF(25-75%), etc. were calculated. The administrative people had higher PFT than the other categories. Drivers and conductors have almost equal mean PFT values but mechanical workers had slightly higher. PFT values according to different age ranges and duration of exposure showed gradual decrement as age and duration of exposure increased. Non-smokers had higher lung volumes compared to smokers and ex-smokers. Restrictive, obstructive and combined types of impairments were noticed in 28.4%, 1.7% and 2.9%, respectively, workers. The restrictive impairment was found to be 30.4% in conductors; 28.9% in drivers, 27.9% in mechanics and 21.7% in administration people. Obstructive type of impairment was found to be 2.9% in both drivers and conductors. The effect of pollution by dust and fumes may be responsible for these pulmonary function impairments, restrictive impairments being greater.

New design of cable-in-conduit conductor for application in future fusion reactors

NASA Astrophysics Data System (ADS)

Qin, Jinggang; Wu, Yu; Li, Jiangang; Liu, Fang; Dai, Chao; Shi, Yi; Liu, Huajun; Mao, Zhehua; Nijhuis, Arend; Zhou, Chao; Yagotintsev, Konstantin A.; Lubkemann, Ruben; Anvar, V. A.; Devred, Arnaud

2017-11-01

The China Fusion Engineering Test Reactor (CFETR) is a new tokamak device whose magnet system includes toroidal field, central solenoid (CS) and poloidal field coils. The main goal is to build a fusion engineering tokamak reactor with about 1 GW fusion power and self-sufficiency by blanket. In order to reach this high performance, the magnet field target is 15 T. However, the huge electromagnetic load caused by high field and current is a threat for conductor degradation under cycling. The conductor with a short-twist-pitch (STP) design has large stiffness, which enables a significant performance improvement in view of load and thermal cycling. But the conductor with STP design has a remarkable disadvantage: it can easily cause severe strand indentation during cabling. The indentation can reduce the strand performance, especially under high load cycling. In order to overcome this disadvantage, a new design is proposed. The main characteristic of this new design is an updated layout in the triplet. The triplet is made of two Nb3Sn strands and one soft copper strand. The twist pitch of the two Nb3Sn strands is large and cabled first. The copper strand is then wound around the two superconducting strands (CWS) with a shorter twist pitch. The following cable stages layout and twist pitches are similar to the ITER CS conductor with STP design. One short conductor sample with a similar scale to the ITER CS was manufactured and tested with the Twente Cable Press to investigate the mechanical properties, AC loss and internal inspection by destructive examination. The results are compared to the STP conductor (ITER CS and CFETR CSMC) tests. The results show that the new conductor design has similar stiffness, but much lower strand indentation than the STP design. The new design shows potential for application in future fusion reactors.

Antifungal activity of ionic liquids based on (-)-menthol: a mechanism study.

PubMed

Suchodolski, Jakub; Feder-Kubis, Joanna; Krasowska, Anna

2017-04-01

The mechanism of toxicity of chiral ionic liquids with (1R,2S,5R)-(-)-menthol [C n -Am-Men][Cl] (n=10, 11 or 12) in the fungus Candida albicans is reported here. Ionic liquids were more toxic towards Candida strain lacking all identified multidrug resistance efflux pumps. Moreover, the compounds tested inhibited C. albicans filamentation at the concentration at which detached fungal cells also adhered to the plastic surface. Our results showed the high activity of all the tested chiral ionic liquids in the permeabilization of C. albicans' membranes and in the digestion and interruption of the cell wall. The investigated ionic liquids thus have potential as disinfectants because besides their antifungal and antiadhesive action these compounds do not cause hemolysis. Copyright © 2017 Elsevier GmbH. All rights reserved.

Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes

NASA Astrophysics Data System (ADS)

Hoarfrost, Megan Lane

Incorporating an ionic liquid into one block copolymer microphase provides a platform for combining the outstanding electrochemical properties of ionic liquids with a number of favorable attributes provided by block copolymers. In particular, block copolymers thermodynamically self-assemble into well-ordered nanostructures, which can be engineered to provide a durable mechanical scaffold and template the ionic liquid into continuous ion-conducting nanochannels. Understanding how the addition of an ionic liquid affects the thermodynamic self-assembly of block copolymers, and how the confinement of ionic liquids to block copolymer nanodomains affects their ion-conducting properties is essential for predictable structure-property control. The lyotropic phase behavior of block copolymer/ionic liquid mixtures is shown to be reminiscent of mixtures of block copolymers with selective molecular solvents. A variety of ordered microstructures corresponding to lamellae, hexagonally close-packed cylinders, body-centered cubic, and face-centered cubic oriented micelles are observed in a model system composed of mixtures of imidazolium bis(trifluoromethylsulfonyl)imide ([Im][TFSI]) and poly(styrene- b-2-vinyl pyridine) (PS-b-P2VP). In contrast to block copolymer/molecular solvent mixtures, the interfacial area occupied by each PS-b-P2VP chain decreases upon the addition of [Im][TFSI], indicating a considerable increase in the effective segregation strength of the PS-b-P2VP copolymer with ionic liquid addition. The relationship between membrane structure and ionic conductivity is illuminated through the development of scaling relationships that describe the ionic conductivity of block copolymer/ionic liquid mixtures as a function of membrane composition and temperature. It is shown that the dominant variable influencing conductivity is the overall volume fraction of ionic liquid in the mixture, which means there is incredible freedom in designing the block copolymer architecture in order to optimize the mechanical and other properties of the membrane without sacrificing conductivity. The derived scaling relationships are shown to be general for many block copolymer and ionic liquid chemistries. In certain cases, the mechanism of ion conduction in the ionic liquid is affected by block copolymer nanoconfinement. The introduction of excess neutral imidazole to [Im][TFSI] leads to enhanced proton conductivity as well as a high H+ transference number due to facilitated proton hopping between imidazole molecules. We show that there is increased proton hopping when the nonstoichiometric ionic liquid is confined to lamellar block copolymer nanodomains, which we hypothesize is due to changes in the hydrogen bond structure of the ionic liquid under confinement. This, in combination with unique ion aggregation behavior, leads to a lower activation energy for macroscopic ion transport compared to that in a corresponding homopolymer/ionic liquid mixture. Through this work, we further the understanding of the relationship between membrane composition, structure, and ion transport. The findings presented herein portend the rational design of nanostructured membranes having improved mechanical properties and conductivity.

Mesoscale studies of ionic closed membranes with polyhedral geometries

DOE PAGES

Olvera de la Cruz, Monica

2016-06-01

Large crystalline molecular shells buckle spontaneously into icosahedra while multicomponent shells buckle into various polyhedra. Continuum elastic theory explains the buckling of closed shells with one elastic component into icosahedra. A generalized elastic model, on the other hand, describes the spontaneous buckling of inhomogeneous shells into regular and irregular polyhedra. By coassembling water-insoluble anionic (–1) amphiphiles with cationic (3+) amphiphiles, we realized ionic vesicles. Results revealed that surface crystalline domains and the unusual shell shapes observed arise from the competition of ionic correlations with charge-regulation. We explain here the mechanism by which these ionic membranes generate a mechanically heterogeneous vesicle.

3-D electrical structure across the Yadong-Gulu rift revealed by magnetotelluric data: New insights on the extension of the upper crust and the geometry of the underthrusting Indian lithospheric slab in southern Tibet

NASA Astrophysics Data System (ADS)

Wang, Gang; Wei, Wenbo; Ye, Gaofeng; Jin, Sheng; Jing, Jianen; Zhang, Letian; Dong, Hao; Xie, Chengliang; Omisore, Busayo O.; Guo, Zeqiu

2017-09-01

The approximately north-south trending Cenozoic Yadong-Gulu rift (YGR) in the eastern Lhasa block is an ideal location to investigate the extensional kinematic mechanism of the upper crust and the deformation characteristics of the Indian lithospheric slab in southern Tibet. The magnetotelluric (MT) method has been widely used in probing subsurface structures at lithospheric scale and is sensitive to high electrically conductive body (conductor). A three-dimensional (3-D) inversion of MT data was conducted to derive the east-west electrical structures across the northern segment of the YGR. The result reveals that the conductors in the middle crust are not continuous in the east-west direction. The deep conductor underneath the YGR is interpreted to result from the tearing of the Indian lithospheric slab. The upper crust to the east of the YGR is significantly intruded by underlying conductors. Based on the features of the 3-D inversion result from this study and other geophysical observations, the formation of the YGR is most likely caused by tearing of the Indian lithospheric slab through the pull of mid-lower crustal conductors that have locally weak strength beneath the YGR.

Thermal Properties and Structural Stability of LaCoO3 in Reducing and Oxidizing Environments

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

Radovic, Miladin; Speakman, Scott A; Allard Jr, Lawrence Frederick

2008-09-01

Thermal expansion of LaCoO3 perovskite in air and 4% H2/96% Ar reducing atmosphere has been studied by Thermal Mechanical Analysis (TMA). The thermal behavior of LaCoO3 in air exhibits a non-linear expansion in 100 400 C temperature range. A significant increase of CTE measured in air both during heating and cooling experiments occurs in the 200 250 C temperature range, corresponding to a known spin state transition. LaCoO3 is found to be unstable in a reducing atmosphere. It undergoes a series of expansion and contractions due to phase transformations beginning around 500 C with very intensive chemical/phase changes at 850oCmore » and above. These expansions and contractions are directly related to the formation of La3Co3O8, La2CoO4, La4Co3O10, La2O3, CoO, and other Co compounds due to the reducing atmosphere. Although LaCoO3 is a good ionic and electronic conductor and catalyst, its high thermal expansion as well structural instability in reducing environments presents a serious restriction for its application in solid oxide fuel cells, sensors or gas separation membranes.« less

Defect chemistry and lithium transport in Li3OCl anti-perovskite superionic conductors.

PubMed

Lu, Ziheng; Chen, Chi; Baiyee, Zarah Medina; Chen, Xin; Niu, Chunming; Ciucci, Francesco

2015-12-28

Lithium-rich anti-perovskites (LiRAPs) are a promising family of solid electrolytes, which exhibit ionic conductivities above 10(-3) S cm(-1) at room temperature, among the highest reported values to date. In this work, we investigate the defect chemistry and the associated lithium transport in Li3OCl, a prototypical LiRAP, using ab initio density functional theory (DFT) calculations and classical molecular dynamics (MD) simulations. We studied three types of charge neutral defect pairs, namely the LiCl Schottky pair, the Li2O Schottky pair, and the Li interstitial with a substitutional defect of O on the Cl site. Among them the LiCl Schottky pair has the lowest binding energy and is the most energetically favorable for diffusion as computed by DFT. This is confirmed by classical MD simulations, where the computed Li ion diffusion coefficients for LiCl Schottky systems are significantly higher than those for the other two defects considered and the activation energy in LiCl deficient Li3OCl is comparable to experimental values. The high conductivities and low activation energies of LiCl Schottky systems are explained by the low energy pathways of Li between the Cl vacancies. We propose that Li vacancy hopping is the main diffusion mechanism in highly conductive Li3OCl.

[Advances of poly (ionic liquid) materials in separation science].

PubMed

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

Ionic Liquids for Advanced Materials

DTIC Science & Technology

2008-12-01

optical clarity to completely opacity with increased amounts of ionic liquid . This transition was not previously observed in Nafion ® membranes swollen...1 IONIC LIQUIDS FOR ADVANCED MATERIALS Timothy E. Long, Sean M. Ramirez, Randy Heflin, Harry W. Gibson, Louis A. Madsen, Donald J. Leo, Nakhiah...is to develop a micromechanical model for the electrochemomechanical transduction mechanisms in newly synthesized ionic liquid polymers in order to

Thermal Decomposition Mechanism of 1-ethyl-3-methylimidazolium Bromide Ionic Liquid (Preprint)

DTIC Science & Technology

2011-09-14

TetraethylammoniumTrifluoromentanesulfonate Ionic Liquid and Neutralized Nafion 117 for High-Temperature Fuel Cells J. Am. Chem. Soc. 2010, 132, 2183-2195. (7) Kim, S. Y.; Kim, S...bromide 5b. GRANT NUMBER ionic liquid (Preprint) 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Steven D. Chambreau, Jerry A. Boatz, Ghanshyam L. Vaaghjiani...In order to better understand the volatilization process for ionic liquids , the vapor evolved from heating the ionic liquid 1-ethyl-3

Application of Ionic Liquids in Amperometric Gas Sensors.

PubMed

Gębicki, Jacek; Kloskowski, Adam; Chrzanowski, Wojciech; Stepnowski, Piotr; Namiesnik, Jacek

2016-01-01

This article presents an analysis of available literature data on metrological parameters of the amperometric gas sensors containing ionic liquids as an electrolyte. Four mechanism types of signal generation in amperometric sensors with ionic liquid are described. Moreover, this article describes the influence of selected physico-chemical properties of the ionic liquids on the metrological parameters of these sensors. Some metrological parameters are also compared for amperometric sensors with GDE and SPE electrodes and with ionic liquids for selected analytes.

Ionic Liquids as Extraction Media for Metal Ions

NASA Astrophysics Data System (ADS)

Hirayama, Naoki

In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

Self-assembled oxide films with tailored nanoscale ionic and electronic channels for controlled resistive switching

NASA Astrophysics Data System (ADS)

Cho, Seungho; Yun, Chao; Tappertzhofen, Stefan; Kursumovic, Ahmed; Lee, Shinbuhm; Lu, Ping; Jia, Quanxi; Fan, Meng; Jian, Jie; Wang, Haiyan; Hofmann, Stephan; MacManus-Driscoll, Judith L.

2016-08-01

Resistive switches are non-volatile memory cells based on nano-ionic redox processes that offer energy efficient device architectures and open pathways to neuromorphics and cognitive computing. However, channel formation typically requires an irreversible, not well controlled electroforming process, giving difficulty to independently control ionic and electronic properties. The device performance is also limited by the incomplete understanding of the underlying mechanisms. Here, we report a novel memristive model material system based on self-assembled Sm-doped CeO2 and SrTiO3 films that allow the separate tailoring of nanoscale ionic and electronic channels at high density (~1012 inch-2). We systematically show that these devices allow precise engineering of the resistance states, thus enabling large on-off ratios and high reproducibility. The tunable structure presents an ideal platform to explore ionic and electronic mechanisms and we expect a wide potential impact also on other nascent technologies, ranging from ionic gating to micro-solid oxide fuel cells and neuromorphics.

Correlating morphology to dc conductivity in polymerized ionic liquids

NASA Astrophysics Data System (ADS)

Iacob, Ciprian; Matusmoto, Atsushi; Inoue, Tadashi; Runt, James

Polymerized ionic liquids (PILs) combine the attractive mechanical characteristics of polymers and unique physico-chemical properties of low molecular weight ionic liquids in the same material. PILs have shown remarkable advantages when employed in electrochemical devices such as dye-sensitized solar cells and lithium batteries, among others. Understanding their ionic transport mechanism is the key for designing highly conductive PILs. In the current study, the correlation between morphology and charge transport in two homologous series of PILs with systematic variation of the alkyl chain length and anions is investigated using broadband dielectric spectroscopy, rheology, differential scanning calorimetry and X-ray scattering. As the alkyl chain length increases, the backbone-to-backbone separation increases, and dc-conductivity consequently decreases. The cations dominate structural dynamics since they are attached to the polymer chains, while the anions are smaller and more mobile ionic species thereby controlling the ionic conductivity. Further interpretation of decoupling of dc conductivity from the segmental relaxation enabled the correlation between polymer morphology and dc conductivity. Supported by the National Science Foundation, Polymers Program.

Graphene nanopore devices for DNA sensing.

PubMed

Merchant, Chris A; Drndić, Marija

2012-01-01

We describe here a method for detecting the translocation of individual DNA molecules through nanopores created in graphene membranes. The devices consist of 1-5-nm thick graphene membranes with electron-beam sculpted nanopores from 5 to 10 nm in diameter. Due to the thin nature of the graphene membranes, and the reduced electrical resistance, we observe larger blocked currents than for traditional solid-state nanopores. We also show how ionic current noise levels can be reduced with the atomic-layer deposition of a few nanometers of titanium dioxide over the graphene surface. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor, and its use opens the door to a new future class of nanopore devices in which electronic sensing and control is performed directly at the pore.

DNA translocation through graphene nanopores.

PubMed

Merchant, Christopher A; Healy, Ken; Wanunu, Meni; Ray, Vishva; Peterman, Neil; Bartel, John; Fischbein, Michael D; Venta, Kimberly; Luo, Zhengtang; Johnson, A T Charlie; Drndić, Marija

2010-08-11

We report on DNA translocations through nanopores created in graphene membranes. Devices consist of 1-5 nm thick graphene membranes with electron-beam sculpted nanopores from 5 to 10 nm in diameter. Due to the thin nature of the graphene membranes, we observe larger blocked currents than for traditional solid-state nanopores. However, ionic current noise levels are several orders of magnitude larger than those for silicon nitride nanopores. These fluctuations are reduced with the atomic-layer deposition of 5 nm of titanium dioxide over the device. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control are performed directly at the pore.

High magnesium mobility in ternary spinel chalcogenides

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

Canepa, Pieremanuele; Bo, Shou-Hang; Sai Gautam, Gopalakrishnan

Magnesium batteries appear a viable alternative to overcome the safety and energy density limitations faced by current lithium-ion technology. Furthermore, the development of a competitive magnesium battery is plagued by the existing notion of poor magnesium mobility in solids. We demonstrate by using ab initio calculations, nuclear magnetic resonance, and impedance spectroscopy measurements that substantial magnesium ion mobility can indeed be achieved in close-packed frameworks (~ 0.01-0.1 mS cm -1 at 298 K), specifically in the magnesium scandium selenide spinel. Our theoretical predictions also indicate that high magnesium ion mobility is possible in other chalcogenide spinels, opening the door formore » the realization of other magnesium solid ionic conductors and the eventual development of an all-solid-state magnesium battery.« less

Alloying effects on superionic conductivity in lithium indium halides for all-solid-state batteries

NASA Astrophysics Data System (ADS)

Zevgolis, Alysia; Wood, Brandon C.; Mehmedović, Zerina; Hall, Alex T.; Alves, Thomaz C.; Adelstein, Nicole

2018-04-01

Alloying of anions is a promising engineering strategy for tuning ionic conductivity in halide-based inorganic solid electrolytes. We explain the alloying effects in Li3InBr6-xClx, in terms of strain, chemistry, and microstructure, using first-principles molecular dynamics simulations and electronic structure analysis. We find that strain and bond chemistry can be tuned through alloying and affect the activation energy and maximum diffusivity coefficient. The similar conductivities of the x = 3 and x = 6 compositions can be understood by assuming that the alloy separates into Br-rich and Cl-rich regions. Phase-separation increases diffusivity at the interface and in the expanded Cl-region, suggesting microstructure effects are critical. Similarities with other halide superionic conductors are highlighted.

High magnesium mobility in ternary spinel chalcogenides

DOE PAGES

Canepa, Pieremanuele; Bo, Shou-Hang; Sai Gautam, Gopalakrishnan; ...

2017-11-24

Magnesium batteries appear a viable alternative to overcome the safety and energy density limitations faced by current lithium-ion technology. Furthermore, the development of a competitive magnesium battery is plagued by the existing notion of poor magnesium mobility in solids. We demonstrate by using ab initio calculations, nuclear magnetic resonance, and impedance spectroscopy measurements that substantial magnesium ion mobility can indeed be achieved in close-packed frameworks (~ 0.01-0.1 mS cm -1 at 298 K), specifically in the magnesium scandium selenide spinel. Our theoretical predictions also indicate that high magnesium ion mobility is possible in other chalcogenide spinels, opening the door formore » the realization of other magnesium solid ionic conductors and the eventual development of an all-solid-state magnesium battery.« less

Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

PubMed Central

Marr, Isabella; Reiß, Sebastian; Hagen, Gunter; Moos, Ralf

2011-01-01

Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers. PMID:22164042

Study of the Fracture Mechanisms of Electroplated Metallization Systems Using In Situ Microtension Test

NASA Astrophysics Data System (ADS)

Msolli, Sabeur; Kim, Heung Soo

2018-07-01

This framework assesses the mechanical behavior of some potential thin/thick metallization systems in use as either ohmic contacts for diamond semi-conductors or for metallization on copper double bounded ceramic substrates present in the next-generation power electronics packaging. The interesting and unique characteristic of this packaging is the use of diamond as a semi-conductor material instead of silicon to increase the lifetime of embedded power converters for use in aeronautical applications. Theoretically, such packaging is able to withstand temperatures of up to 300 °C without breaking the semi-conductor, provided that the constitutive materials of the packaging are compatible. Metallization is very important to protect the chips and substrates. Therefore, we address this issue in the present work. The tested metallization systems are Ni/Au, Ni/Cr/Au and Ni/Cr. These specific systems were studied since they can be used in conjunction with existing bonding technologies, including AuGe soldering, Ag-In Transient liquid Phase Bonding and silver nanoparticle sintering. The metallization is achieved via electrodeposition, and a mechanical test, consisting of a microtension technique, is carried out at room temperature inside a scanning electron microscopy chamber. The technique permits observations the cracks initiation and growth in the metallization to locate the deformation zones and identify the fracture mechanisms. Different failure mechanisms were shown to occur depending on the metallic layers deposited on top of the copper substrate. The density of these cracks depends on the imposed load and the involved metallization. These observations will help choose the metallization that is compatible with the particular bonding material, and manage mechanical stress due to thermal cycling so that they can be used as a constitutive component for high-temperature power electronics packaging.

Study of the Fracture Mechanisms of Electroplated Metallization Systems Using In Situ Microtension Test

NASA Astrophysics Data System (ADS)

Msolli, Sabeur; Kim, Heung Soo

2018-03-01

This framework assesses the mechanical behavior of some potential thin/thick metallization systems in use as either ohmic contacts for diamond semi-conductors or for metallization on copper double bounded ceramic substrates present in the next-generation power electronics packaging. The interesting and unique characteristic of this packaging is the use of diamond as a semi-conductor material instead of silicon to increase the lifetime of embedded power converters for use in aeronautical applications. Theoretically, such packaging is able to withstand temperatures of up to 300 °C without breaking the semi-conductor, provided that the constitutive materials of the packaging are compatible. Metallization is very important to protect the chips and substrates. Therefore, we address this issue in the present work. The tested metallization systems are Ni/Au, Ni/Cr/Au and Ni/Cr. These specific systems were studied since they can be used in conjunction with existing bonding technologies, including AuGe soldering, Ag-In Transient liquid Phase Bonding and silver nanoparticle sintering. The metallization is achieved via electrodeposition, and a mechanical test, consisting of a microtension technique, is carried out at room temperature inside a scanning electron microscopy chamber. The technique permits observations the cracks initiation and growth in the metallization to locate the deformation zones and identify the fracture mechanisms. Different failure mechanisms were shown to occur depending on the metallic layers deposited on top of the copper substrate. The density of these cracks depends on the imposed load and the involved metallization. These observations will help choose the metallization that is compatible with the particular bonding material, and manage mechanical stress due to thermal cycling so that they can be used as a constitutive component for high-temperature power electronics packaging.

Theoretical investigation of the interaction between aromatic sulfur compounds and [BMIM](+)[FeCl4](-) ionic liquid in desulfurization: A novel charge transfer mechanism.

PubMed

Li, Hongping; Zhu, Wenshuai; Chang, Yonghui; Jiang, Wei; Zhang, Ming; Yin, Sheng; Xia, Jiexiang; Li, Huaming

2015-06-01

In this work, interaction nature between a group of aromatic sulfur compounds and [BMIM](+)[FeCl4](-) have been investigated by density functional theory (DFT). A coordination structure is found to be critical to the mechanism of extractive desulfurization. Interaction energy and extractive selectivity follow the order: thiophene (TH)

Vector Analysis of Ionic Collision on CaCO3 Precipitation Based on Vibration Time History

NASA Astrophysics Data System (ADS)

Mangestiyono, W.; Muryanto, S.; Jamari, J.; Bayuseno, A. P.

2017-05-01

Vibration effects on the piping system can result from the internal factor of fluid or the external factor of the mechanical equipment operation. As the pipe vibrated, the precipitation process of CaCO3 on the inner pipe could be affected. In the previous research, the effect of vibration on CaCO3 precipitation in piping system was clearly verified. This increased the deposition rate and decreased the induction time. However, the mechanism of vibration control in CaCO3 precipitation process as the presence of vibration has not been recognized yet. In the present research, the mechanism of vibration affecting the CaCO3 precipitation was investigated through vector analysis of ionic collision. The ionic vector force was calculated based on the amount of the activation energy and the vibration force was calculated based on the vibration sensor data. The vector resultant of ionic collision based on the vibration time history was analyzed to prove that vibration brings ionic collision randomly to the planar horizontal direction and its collision model was suspected as the cause of the increasing deposition rate.

Mechanisms of Electrical Activation and Conduction in the Gastrointestinal System: Lessons from Cardiac Electrophysiology

PubMed Central

Tse, Gary; Lai, Eric Tsz Him; Yeo, Jie Ming; Tse, Vivian; Wong, Sunny Hei

2016-01-01

The gastrointestinal (GI) tract is an electrically excitable organ system containing multiple cell types, which coordinate electrical activity propagating through this tract. Disruption in its normal electrophysiology is observed in a number of GI motility disorders. However, this is not well characterized and the field of GI electrophysiology is much less developed compared to the cardiac field. The aim of this article is to use the established knowledge of cardiac electrophysiology to shed light on the mechanisms of electrical activation and propagation along the GI tract, and how abnormalities in these processes lead to motility disorders and suggest better treatment options based on this improved understanding. In the first part of the article, the ionic contributions to the generation of GI slow wave and the cardiac action potential (AP) are reviewed. Propagation of these electrical signals can be described by the core conductor theory in both systems. However, specifically for the GI tract, the following unique properties are observed: changes in slow wave frequency along its length, periods of quiescence, synchronization in short distances and desynchronization over long distances. These are best described by a coupled oscillator theory. Other differences include the diminished role of gap junctions in mediating this conduction in the GI tract compared to the heart. The electrophysiology of conditions such as gastroesophageal reflux disease and gastroparesis, and functional problems such as irritable bowel syndrome are discussed in detail, with reference to ion channel abnormalities and potential therapeutic targets. A deeper understanding of the molecular basis and physiological mechanisms underlying GI motility disorders will enable the development of better diagnostic and therapeutic tools and the advancement of this field. PMID:27303305

RAPID COMMUNICATION: Effect of strain, magnetic field and field angle on the critical current density of Y Ba2Cu3O7-δ coated conductors

NASA Astrophysics Data System (ADS)

van der Laan, D. C.; Ekin, J. W.; Douglas, J. F.; Clickner, C. C.; Stauffer, T. C.; Goodrich, L. F.

2010-07-01

A large, magnetic-field-dependent, reversible reduction in critical current density with axial strain in Y Ba2Cu3O7-δ coated conductors at 75.9 K has been measured. This effect may have important implications for the performance of Y Ba2Cu3O7-δ coated conductors in applications where the conductor experiences large stresses in the presence of a magnetic field. Previous studies have been performed only under tensile strain and could provide only a limited understanding of the in-field strain effect. We now have constructed a device for measuring the critical current density as a function of axial compressive and tensile strain and applied magnetic field as well as magnetic field angle, in order to determine the magnitude of this effect and to create a better understanding of its origin. The reversible reduction in critical current density with strain becomes larger with increasing magnetic field at all field angles. At 76 K the critical current density is reduced by about 30% at - 0.5% strain when a magnetic field of 5 T is applied parallel to the c-axis of the conductor or 8 T is applied in the ab-plane, compared to a reduction of only 13% in self-field. Differences in the strain response of the critical current density at various magnetic field angles indicate that the pinning mechanisms in Y Ba2Cu3O7-δ coated conductors are uniquely affected by strain. Contribution of NIST, not subject to US copyright.

Studies on Ionic Conductivity and Electrochemical Stability of Plasticized Photopolymerized Polymer Electrolyte Membranes for Solid State Lithium Ion Batteries

NASA Astrophysics Data System (ADS)

He, Ruixuan

In pursuit of safer and more flexible solid-state lithium ion batteries, solid polymer electrolytes have emerged as a promising candidate. The present dissertation entails exploration of solid plasticized, photopolymerized (i.e. ultraviolent-cured) polymer electrolyte membranes (PEM) for fulfilling the critical requirements of electrolytes, such as high ionic conductivity and good thermal and electrochemical stability, among others. Electrochemical performance of PEMs containing lithium ion half-cells was also investigated at different two temperatures. Phase diagram approach was adopted to guide the fabrication of two types of plasticized PEMs. Prepolymer poly (ethylene glycol) diacrylate (PEGDA) was used as a matrix for building an ionic conductive and mechanically sturdy network. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was incorporated as a source of lithium ions, while a solid plasticizer succinonitrile (SCN) and a liquid plasticizer tetraethylene glycol dimethyl ether (TEGDME) were incorporated in the respective systems. The important role of plasticizer on the enhancement of ionic conductivity (sigma) to the superionic conductive level (10-3 S/cm) was revealed in both systems. It is worth noting that photopolymerization induced crystallization (PIC) occurred during UV-curing in the SCN-rich region of the ternary PEGDA/LiTFSI/SCN ternary mixtures. The PEM thus formed contained a plastic crystal phase, which showed lower σ relative to their amorphous PEGDA/LiTFSI/TEGDME counterpart. Comparisons on other thermal and electrochemical properties of the two types of PEMs are presented in Chapter IV. For the PEGDA/LiTFSI/SCN PEMs, fundamental study was carried out to clarify the relationship between σ and glass transition temperature (T g). In lithium salt/polymer binary PEMs, increase in Tg and reduction in σ were observed; these may be attributed to ion-dipole complexation between dissociated lithium cations and ether oxygen upon salt addition. Notably, above the threshold salt concentration of 7 mol %, dual loss tangent peaks were observed in dynamic mechanical studies. These might be ascribed to segmental relaxations of ion-dipole complexed networks and that of polymer chains surrounding the undissociated lithium salt acting like "fillers". Upon SCN incorporation, these two peaks merged into one that was further suppressed below the Tg of the pure network, whereas σ improved to the superionic conductor level. The role of SCN on the σ enhancement as both plasticizer for the polymer network and ionizer for the salt is discussed in Chapter V. In order to improve the mechanical toughness of the highly conductive PEGDA/LiTFSI/SCN PEM, effects of prepolymer molecular weight on mechanical and electrochemical properties of PEMs were further investigated. By increasing molecular weight of PEGDA from 700 to 6000 g/mol, toughness and elongation at break were enhanced as expected. Interestingly, improved ionic conductivity was achieved simultaneously. The dual improvement may be attributed to the less chemical crosslinked points and the more flexible chain motion in the looser network of PEGDA6000-PEM relative to its PEGDA700 counterpart. Subsequently, high thermal stability and electrochemical stability of both types of PEMs, as well as the satisfactory room temperature charge/discharge cycling performance of PEM containing lithium ion half-cells were observed. The pertinent information is documented in Chapter VI. Finally, the investigation of the charge/discharge cycling performance of solid-state LiFePO4 half-cells at an elevated temperature of 60°C is discussed in Chapter VII. In the half-cells, particularly, SCN plasticized PEMs with and without electrolyte modifier lithium bis(oxalato)borate (LiBOB) were respectively employed. Rapid decline of capacity and increase of cell resistance were found in the unmodified PEM containing cell; however, these deteriorations were greatly suppressed upon LiBOB modification. Electrochemical and thermal compatibility of PEMs towards different electrodes were examined in several symmetric cells and half-cells. Detailed characterization on LiFePO 4 electrodes and PEMs retrieved from these cells implied that the observed battery failure might be triggered by an amide-forming side reaction that took place at the interface of a SCN plasticized PEM and a lithium electrode at high temperature. Of particular importance is the fact that this detrimental side reaction was effectively suppressed upon LiBOB electrolyte modifier addition. Plausible mechanisms are discussed.

Ion Conduction in Polymerized Ionic Liquids with Different Pendant Groups

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

Fan, Fei; Wang, Yangyang; Hong, Tao

2015-07-17

Polymerized ionic liquids (PolyILs) are promising candidates for energy storage and electrochemical devices applications. Understanding their ionic transport mechanism is the key for designing highly conductive PolyILs. By using broadband dielectric spectroscopy (BDS), rheology, and differential scanning calorimetry (DSC), a systematic study has been carried out to provide a better understanding of the ionic transport mechanism in PolyILs with different pendant groups. The variation of pendant groups results in different dielectric, mechanical, and thermal properties of these PolyILs. The Walden plot analysis shows that the data points for all these PolyILs fall above the ideal Walden line, and the deviationmore » from the ideal line increases upon approaching the glass transition temperature (T g). Moreover, the conductivity for these PolyILs at their Tgs are much higher than the usually reported value 10 15 S/cm for polymer electrolytes, in which the ionic transport is closely coupled to the segmental dynamics. These results indicate a decoupling of ionic conductivity from the segmental relaxation in these materials. The degree of decoupling increases with the increase of the fragility of polymer segmental relaxation. Finally, we relate this observation to a decrease in polymer packing efficiency with an increase in fragility.« less

Composite lead for conducting an electrical current between 75--80K and 4. 5K temperatures

DOEpatents

Negm, Y.; Zimmerman, G.O.; Powers, R.E. Jr.; McConeghy, R.J.; Kaplan, A.

1994-12-27

A composite lead is provided which electrically links and conducts a current between about 75-80K and liquid helium temperature of about 4.5K. The composite lead may be employed singly or in multiples concurrently to provide conduction of electrical current from normal conductors and semi-conductors at room temperature to superconductors operating at 4.5K. In addition, a variety of organizational arrangements and assemblies are provided by which the mechanical strength and electrical reliability of the composite lead is maintained. 12 figures.

Composite lead for conducting an electrical current between 75-80K and 4.5K temperatures

DOEpatents

Negm, Yehia; Zimmerman, George O.; Powers, Jr., Robert E.; McConeghy, Randy J.; Kaplan, Alvaro

1994-12-27

A composite lead is provided which electrically links and conducts a current between about 75-80K. and liquid helium temperature of about 4.5K. The composite lead may be employed singly or in multiples concurrently to provide conduction of electrical current from normal conductors and semi-conductors at room temperature to superconductors operating at 4.5K. In addition, a variety of organizationl arrangements and assemblies are provided by which the mechanical strength and electrical reliability of the composite lead is maintained.

Role of Oxygen in Ionic Liquid Gating on Two-Dimensional Cr2Ge2Te6: A Non-oxide Material.

PubMed

Chen, Yangyang; Xing, Wenyu; Wang, Xirui; Shen, Bowen; Yuan, Wei; Su, Tang; Ma, Yang; Yao, Yunyan; Zhong, Jiangnan; Yun, Yu; Xie, X C; Jia, Shuang; Han, Wei

2018-01-10

Ionic liquid gating can markedly modulate a material's carrier density so as to induce metallization, superconductivity, and quantum phase transitions. One of the main issues is whether the mechanism of ionic liquid gating is an electrostatic field effect or an electrochemical effect, especially for oxide materials. Recent observation of the suppression of the ionic liquid gate-induced metallization in the presence of oxygen for oxide materials suggests the electrochemical effect. However, in more general scenarios, the role of oxygen in the ionic liquid gating effect is still unclear. Here, we perform ionic liquid gating experiments on a non-oxide material: two-dimensional ferromagnetic Cr 2 Ge 2 Te 6 . Our results demonstrate that despite the large increase of the gate leakage current in the presence of oxygen, the oxygen does not affect the ionic liquid gating effect on  the channel resistance of Cr 2 Ge 2 Te 6 devices (<5% difference), which suggests the electrostatic field effect as the mechanism on non-oxide materials. Moreover, our results show that ionic liquid gating is more effective on the modulation of the channel resistances compared to the back gating across the 300 nm thick SiO 2 .

Visualization of Biomass Solubilization and Cellulose Regeneration during Ionic Liquid Pretreatment of Switchgrass

USDA-ARS?s Scientific Manuscript database

Auto-fluorescent mapping of plant cell walls was used to visualize cellulose and lignin in pristine switchgrass (Panicum virgatum) stems to determine the mechanisms of biomass dissolution during ionic liquid pretreatment. The addition of ground switchgrass to the ionic liquid 1-n-ethyl-3-methylimid...

Externalized conductors and insulation failure in Biotronik defibrillator leads: History repeating or a false alarm?

PubMed

De Maria, Elia; Borghi, Ambra; Bonetti, Lorenzo; Fontana, Pier Luigi; Cappelli, Stefano

2017-02-16

Conductor externalization and insulation failure are frequent complications with the recalled St. Jude Medical Riata implantable cardioverter-defibrillator (ICD) leads. Conductor externalization is a "unique" failure mechanism: Cables externalize through the insulation ("inside-out" abrasion) and appear outside the lead body. Recently, single reports described a similar failure also for Biotronik leads. Moreover, some studies reported a high rate of electrical dysfunction (not only insulation failure) with Biotronik Linox leads and a reduced survival rate in comparison with the competitors. In this paper we describe the case of a patient with a Biotronik Kentrox ICD lead presenting with signs of insulation failure and conductor externalization at fluoroscopy. Due to the high risk of extraction we decided to implant a new lead, abandoning the damaged one; lead reimplant was uneventful. Subsequently, we review currently available literature about Biotronik Kentrox and Linox ICD lead failure and in particular externalized conductors. Some single-center studies and a non-prospective registry reported a survival rate between 88% and 91% at 5 years for Linox leads, significantly worse than that of other manufacturers. However, the preliminary results of two ongoing multicenter, prospective registries (GALAXY and CELESTIAL) showed 96% survival rate at 5 years after implant, well within industry standards. Ongoing data collection is needed to confirm longer-term performance of this family of ICD leads.

Externalized conductors and insulation failure in Biotronik defibrillator leads: History repeating or a false alarm?

PubMed Central

De Maria, Elia; Borghi, Ambra; Bonetti, Lorenzo; Fontana, Pier Luigi; Cappelli, Stefano

2017-01-01

Conductor externalization and insulation failure are frequent complications with the recalled St. Jude Medical Riata implantable cardioverter-defibrillator (ICD) leads. Conductor externalization is a “unique” failure mechanism: Cables externalize through the insulation (“inside-out” abrasion) and appear outside the lead body. Recently, single reports described a similar failure also for Biotronik leads. Moreover, some studies reported a high rate of electrical dysfunction (not only insulation failure) with Biotronik Linox leads and a reduced survival rate in comparison with the competitors. In this paper we describe the case of a patient with a Biotronik Kentrox ICD lead presenting with signs of insulation failure and conductor externalization at fluoroscopy. Due to the high risk of extraction we decided to implant a new lead, abandoning the damaged one; lead reimplant was uneventful. Subsequently, we review currently available literature about Biotronik Kentrox and Linox ICD lead failure and in particular externalized conductors. Some single-center studies and a non-prospective registry reported a survival rate between 88% and 91% at 5 years for Linox leads, significantly worse than that of other manufacturers. However, the preliminary results of two ongoing multicenter, prospective registries (GALAXY and CELESTIAL) showed 96% survival rate at 5 years after implant, well within industry standards. Ongoing data collection is needed to confirm longer-term performance of this family of ICD leads. PMID:28255544

Organic mixed conductors for bioelectronic applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Rivnay, Jonathan

2016-09-01

Direct measurement and stimulation of electrophysiological activity is a staple of neural and cardiac health monitoring, diagnosis and/or therapy. The ability to sensitively detect these signals can be enhanced by organic electronic materials that show mixed conduction properties (both electronic and ionic transport) in order to bridge the inherent mismatch that is prevalent between biological systems and traditional microelectronic materials/devices. Organic electrochemical transistors (OECTs) are one class of devices that utilize organic mixed conductors as the transistor channel, and have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance. These devices are fabricated in flexible, conformable form factors for in vivo recordings of epileptic activity, and for cutaneous EEG and ECG recordings in human subjects. The majority of high performance devices are based on conducting polymers such as poly(3,4-ethylenedioxythiophene) :poly(styrenesulfonate), PEDOT:PSS. By investigating PEDOT-based materials and devices, we are able to construct design rules for new formulations/materials. Introducing glycolated side chains to carefully selected semiconducting polymer backbones has enabled a new class high performance bioelectronic materials that feature high volumetric capacitance, transconductance >10mS (device dimensions ca. 10um), and steep subthreshold switching characteristics. A sub-set of these materials outperform PEDOT:PSS and shows significant promise for low power in vitro and in vivo biosensing applications.

Neuron-Glia Interactions and Nervous System Homeostasis

DTIC Science & Technology

1988-06-01

active neuron states, the mechanisms which glial cells and neurons use to modulate each others metabolic state and the chemical, electrical and... mechanisms by which axons/neurons and their glial cell investments communicate to actively regulate the ionic microenvironment of the nervous system and...of the glial cell in maintenance of the ionic homeostasis of the perineural environment during resting and active neuron states, the mechanisms which

46 CFR 111.60-17 - Connections and terminations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... general, connections and terminations to all conductors must retain the original electrical, mechanical, flame-retarding, and, where necessary, fire-resisting properties of the cable. All connecting devices...

46 CFR 111.60-17 - Connections and terminations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... general, connections and terminations to all conductors must retain the original electrical, mechanical, flame-retarding, and, where necessary, fire-resisting properties of the cable. All connecting devices...

Synthesis and Study on Ionic Conductive (Bi1−x,Vx)O1.5−δ Materials with a Dual-Phase Microstructure

PubMed Central

Lai, Yu-Wei; Wei, Wen-Cheng J.

2016-01-01

Homogeneous Bi2O3-V2O5 powder mixtures with different amounts of V2O5 content (≤15 mol%) were prepared by colloidal dispersion and sintering to high density. The sintered and annealed samples were studied by thermal analysis, quantitative X-ray diffraction and scanning electron microscopy. The electrical and ionic conductivities of the conductors were also measured by a four-probe direct current (DC) method. The results of the samples prepared at 600–800 °C and annealed for as long as 100 h show that the sintered samples consisting of a pure γ phase or δ + γ binary phase perform differently in conductivity. The highly conductive δ phase in the composition of Bi0.92V0.08O1.5−δ enhances the electric conductivity 10-times better than that of the pure γ-sample (Bi0.94V0.06O1.5−δ) between 400 and 600 °C. The compatible regions of the γ phase with the α- or δ phase are also reported and discussed, so a part of the previously published Bi2O3-V2O5 phase diagram below 800 °C is revised. PMID:28773981

Magneto-Ionic Control of Interfacial Magnetic Anisotorpy

NASA Astrophysics Data System (ADS)

Bauer, Uwe; Emori, Satoru; Beach, Geoffrey

2014-03-01

Voltage control of magnetism could bring about revolutionary new spintronic memory and logic devices. Here, we examine domain wall (DW) dynamics in ultrathin Co films and nanowires under the influence of a voltage applied across a gadolinium oxide gate dielectric that simultaneously acts as an oxygen ion conductor. We investigate two electrode configurations, one with a continuous gate dielectric and the other with a patterned gate dielectric which exhibits an open oxide edge right underneath the electrode perimeter. We demonstrate that the open oxide edge acts as a fast diffusion path for oxygen ions and allows voltage-induced switching of magnetic anisotropy at the nanoscale by modulating interfacial chemistry rather than charge density. At room temperature this effect is limited to the vicinity of the open oxide edge, but at a temperature of 100°C it allows complete control over magnetic anisotropy across the whole electrode area, due to higher oxygen ion mobility at elevated temperature. We then harness this novel ``magneto-ionic'' effect to create unprecedentedly strong voltage-induced anisotropy modifications of 3000 fJ/Vm and create electrically programmable DW traps with pinning strengths of 650 Oe, enough to bring to a standstill DWs travelling at speeds of at least 20 m/s. This work is supported by the National Science Foundation through grant ECCS-1128439.

Powder-metallurgical preparation of A15 superconductors

NASA Astrophysics Data System (ADS)

Wilhelm, Manfred; Wohlleben, Karl; Springer, Engelbert; Mrowiec, Klaus; Schaper, Wilfried; Wecker, Joachim

1985-08-01

The powder-metallurgical preparation of Cu-Nb3Sn microcomposite superconductors was investigated in order to economize in the manufacture of the conductors and to improve their mechanical and electrical properties. Conditions during high temperature extrusion are optimized by adding Al or Ti as reducing agents, also with a view to the following cold forming. Current densities well above 10,000 A/sq cm at 15T are obtained by applying coarse-grained Nb powder and incorporating small quantities of Ta or Ti. The current carrying behavior of the conductors was determined as a function of the degree of mechanical deformation, the cold forming technique, and the heat treatment conditions. Wires containing an internal tin source as well as bundled assemblies for high current applications were manufactured. Long wires can be produced.

Rechargeable thin-film electrochemical generator

DOEpatents

Rouillard, Roger; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Ranger, Michel; Sudano, Anthony; Trice, Jennifer L.; Turgeon, Thomas A.

2000-09-15

An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

PubMed

Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

2012-08-07

To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance.

Self-assembled oxide films with tailored nanoscale ionic and electronic channels for controlled resistive switching

DOE PAGES

Cho, Seungho; Yun, Chao; Tappertzhofen, Stefan; ...

2016-08-05

Resistive switches are non-volatile memory cells based on nano-ionic redox processes that offer energy efficient device architectures and open pathways to neuromorphics and cognitive computing. However, channel formation typically requires an irreversible, not well controlled electroforming process, giving difficulty to independently control ionic and electronic properties. The device performance is also limited by the incomplete understanding of the underlying mechanisms. Here, we report a novel memristive model material system based on self-assembled Sm-doped CeO 2 and SrTiO 3 films that allow the separate tailoring of nanoscale ionic and electronic channels at high density (~10 12 inch –2). Here, we systematicallymore » show that these devices allow precise engineering of the resistance states, thus enabling large on–off ratios and high reproducibility. The tunable structure presents an ideal platform to explore ionic and electronic mechanisms and we expect a wide potential impact also on other nascent technologies, ranging from ionic gating to micro-solid oxide fuel cells and neuromorphics.« less

The Influence of Music Style and Conductor Race on Perceptions of Ensemble and Conductor Performance

ERIC Educational Resources Information Center

Vanweelden, Kimberly; McGee, Isaiah R.

2007-01-01

The purpose of this study was to examine music style and conductor race on perceptions of ensemble and conductor performance. Results found that conductor race and music style significantly affected ratings of ensemble and conductor performance. Evaluators rated a white conductor group higher than a black conductor group conducting the same…

Enhancement of force generated by individual myosin heads in skinned rabbit psoas muscle fibers at low ionic strength.

PubMed

Sugi, Haruo; Abe, Takahiro; Kobayashi, Takakazu; Chaen, Shigeru; Ohnuki, Yoshiki; Saeki, Yasutake; Sugiura, Seiryo

2013-01-01

Although evidence has been presented that, at low ionic strength, myosin heads in relaxed skeletal muscle fibers form linkages with actin filaments, the effect of low ionic strength on contraction characteristics of Ca(2+)-activated muscle fibers has not yet been studied in detail. To give information about the mechanism of muscle contraction, we have examined the effect of low ionic strength on the mechanical properties and the contraction characteristics of skinned rabbit psoas muscle fibers in both relaxed and maximally Ca(2+)-activated states. By progressively decreasing KCl concentration from 125 mM to 0 mM (corresponding to a decrease in ionic strength μ from 170 mM to 50 mM), relaxed fibers showed changes in mechanical response to sinusoidal length changes and ramp stretches, which are consistent with the idea of actin-myosin linkage formation at low ionic strength. In maximally Ca(2+)-activated fibers, on the other hand, the maximum isometric force increased about twofold by reducing KCl concentration from 125 to 0 mM. Unexpectedly, determination of the force-velocity curves indicated that, the maximum unloaded shortening velocity Vmax, remained unchanged at low ionic strength. This finding indicates that the actin-myosin linkages, which has been detected in relaxed fibers at low ionic strength, are broken quickly on Ca(2+) activation, so that the linkages in relaxed fibers no longer provide any internal resistance against fiber shortening. The force-velocity curves, obtained at various levels of steady Ca(2+)-activated isometric force, were found to be identical if they are normalized with respect to the maximum isometric force. The MgATPase activity of muscle fibers during isometric force generation was found not to change appreciably at low ionic strength despite the two-fold increase in Ca(2+)-activated isometric force. These results can be explained in terms of enhancement of force generated by individual myosin heads, but not by any changes in kinetic properties of cyclic actin-myosin interaction.

Simultaneous improvement in ionic conductivity and flexibility of solid polymer electrolytes for thin film lithium ion batteries

NASA Astrophysics Data System (ADS)

Ji, Jianying

Solid polymer electrolytes (SPEs) provide advantages over liquid electrolytes in terms of safety, reliability, less temperature sensitive, and simplicity of design. With the use of a SPE in lithium batteries, high specific energy and specific power, safe operation, flexibility in packaging, and low cost of fabrication can be expected. However, after 30 years, SPEs have rarely found commercial success due to the low ionic conductivity and/or insufficient mechanical properties, both of which are related to the movement of the polymer chains. Many physical/chemical methods have been exploited to simultaneously create enhancement in ionic conductivity and mechanical properties, and some suggested ways have shown promise. However, the complex strategies have always introduced other challenge issues and incurred extra costs for manufacturing. In such a context, the development of dry solid state electrolytes is the central challenge to be faced worldwide. This thesis deals with the approaches to improving ionic conductivity and mechanical properties simultaneously. The method is to apply two kinds of controllable organic fillers: copolymer and protein. Our work revealed that the commercial available copolymer, poly (ethylene oxide)- block-polyethylene (PEO-b-PE), possesses a capability for enhancing the multiple performances of poly(ethylene oxide)(PEO)-based polymer electrolyte. And the effects of composition and molecular weight of the copolymers on performance of the resulting SPEs were examined. It was found that increasing the PE block percentage in the copolymer resulted in a significant increase in both ionic conductivity and mechanical properties, while increasing the molecular weight of the copolymer resulted in better mechanical properties, and an identical ionic conductivity. A rubber-like, soy protein-based SPE (s-SPE)was obtained by employing soy protein isolate (SPI), a soy product usually used as rigid fillers for enhancing mechanical properties of polymers, blended with poly(ethylene oxide)(PEO). The results indicated that the s-SPE with 55 wt% of SPI possesses a fully amorphous uniform structure having low Tg, in contrast with crystalline PEO-based SPE having discernable Tg and Tm. The conductivity and elasticity are both significantly improved with SPI involvement. Remarkably, this film has been elongated up to 100% without loss of ionic conductivity and 700% without mechanical damage.

Bipolar leads for use with permanently implantable cardiac pacing systems: a review of limitations of traditional and coaxial configurations and the development and testing of new conductor, insulation, and electrode designs.

PubMed

Tyers, G F; Mills, P; Clark, J; Cheesman, M; Yeung-Lai-Wah, J A; Brownlee, R R

1997-01-01

The unacceptable rate of mechanical failures, threshold problems, and recalls experienced with many coaxial bipolar cardiac pacing lead designs are reviewed in detail. To address these problems, redundant insulation coradial atrial and ventricular tined leads (AL and VL, respectively) with iridium oxide electrodes were developed and subjected to extensive accelerated testing. There were no mechanical failures. The new lead body design proved to be much more durable than widely used trifilar MP35N configurations. The data reviewed and early and current test results are strongly supportive of tightly coupled insulation being a major factor in improving lead durability as long as the insulating material is not stressed. In addition to improving flex life, insulation adherence to the conductor may reduce the potential for ionic degradation. Pacing and sensing thresholds in animal studies of the new leads were within the reported range for leads with steroid eluting electrodes. A multicenter Canadian clinical trial was initiated with the first implant in early January 1994. By November 1995, 110 VL and 82 AL had been placed in 124 patients and followed for a mean of 11 +/- 6 months; maximum 21, total 1355. There were 60 males and 64 females with a mean age of 64 +/- 16 years, range 15-88. Primary indications for pacing were AV block in 61 patients, sick sinus syndrome in 53, vasovagal syncope in 4, and congestive heart failure in 7. Many patients had associated or primary tachyarrhythmias, including 111 with supraventricular and 12 with ventricular. Forty-two percent of patients (52/124) had prior cardiac procedures, including 18 open heart surgeries and 20 AV nodal ablations. At implant, 8 lead characteristics were rated good or excellent in 90% (746/829) of evaluations. X-ray visibility was of concern in 10% of patients (12/124). Three perioperative complications occurred, including displacement of one AL (1.2%) and one VL (0.9%). There were no subsequent mechanical (connector, conductor, or insulation) or functional (exit block, micro or macro displacement, or over- or undersensing) problems. Implant pacing thresholds (PT) at 0.45 ms were AL, 0.6 +/- 0.2 (74) and VL 0.4 +/- 0.2 V; impedance (Z) at 3.5 V output AL 373 +/- 77 (82) and VL 497 +/- 117 omega. Sensing thresholds (ST) were AL 3.1 +/- 1.6 (74) and VL 10.3 +/- 4.9 mV. Ventricular lead data were obtained for all patients (N = 110). Atrial lead data are incomplete, because some patients were in atrial fibrillation during implantation. After 12 months, AL PT at 1.5 V output was 0.18 +/- 0.10 ms (21) and at 2.5 V was 0.10 +/- 0.053 (22). Associated AL ST was 3.3 +/- 0.9 mV (21) AL Z 500 +/- 65 omega (25). After 18 months VL PT at 1.5 V was 0.15 +/- 0.10 ms (9) and at 2.5 V output was 0.09 +/- 0.04 ms (9). Associated VL ST was > 7.5 +/- 2.4 mV (9) and VL Z 497 +/- 105 omega (9). Follow-up time discrepancy is due to the VL being available 6 months earlier than the AL. There were no 30-day deaths and only one late death at 10 months in a patient with chronic atrial fibrillation. Death was unrelated to pacer or lead function. At 1 year, 68% AL (15/22) and 62% (24/39) captured at 0.5 V and < or = 1 ms pulse width output. Innovative adherent insulation coradial bipolar lead conductors of the design studied combined with coated iridium oxide electrodes provide for a negligible incidence of mechanical or functional failure with clinical follow-up now approaching 3 years. Excellent acute and chronic sensing and pacing thresholds have been documented. Late thresholds have continued to improve gradually. Long-term clinical pacing at < or = 1.5 V output with a large safety margin is feasible in essentially all patients. This coradial design produces very flexible < 5 French bipolar redundantly insulated lead bodies allowing both AL and VL to simultaneously pass through a single 10 French introducer sheath. (ABSTRACT TRUNCATED)

Doping and defect structure of mixed-conducting ceramics for gas separation

NASA Astrophysics Data System (ADS)

Zuo, Chendong

A worldwide energy crisis and increasing environmental concerns are strong incentives for using hydrogen as a sustainable and clean energy source. "Hydrogen economy" has been around since 1970s, but it started to look practicable only in recent years. The trend in the future is to switch from using hydrogen as the basic raw material in the chemical industry to the energy carrier in the transportation and distributed energy industries. To meet the expected rising demand, hydrogen has to be generated in a more cost-effective manner. As one of the most important operation units in the hydrogen production, a high performance hydrogen separation membrane system is essential to the coming hydrogen economy. The project of hydrogen separation membrane based on Mixed ionic and electronic conductor (MIEC) composite was initiated by DoE years ago, and the MIEC membrane has been developed in Argonne National Laboratory (ANL) for several years. The goal at ANL is to develop a dense, ceramic-based MIEC membrane that is highly selective, chemical stable in practical environments at operative temperatures up to ≈900°C, and can separate hydrogen from mixed gases at commercially significant fluxes under industrially relevant operating conditions, without the need for electrodes or electrical circuitry. The effort at ANL initially focused on BCY20 (BaCe0.8Y 0.2O3). BCY20 forms the matrix of ANL-1a and -2a ceramic-metal composite membranes (40-50 vol.% of a metal is dispersed in a ceramic matrix) and its bulk transport properties, including ionic transfer number, ionic and electronic conductivity, and chemical and mechanical stability have been systematically studied. However, exposure to CO2 and H2O-containing atmospheres, as would be present in a practical environment, will degrade the material as it reacts to form insulating barium carbonate (BaCO3 ) and cerium oxide (CeO2). This decomposition greatly limits its applicability in hydrogen separation, despite the promising properties of this material. The combination of high proton conductivity and good chemical stability, which is a prerequisite for the application of MIEC compounds, is generally considered to be a key problem. In choosing good materials for H2 separation membrane, defect structure, and hence transport properties of perovskites, which are strongly influenced by the oxidation states and ionic radii of dopants, are very critical. Therefore it is the goal of this research to gain a fundamental understanding of the correlation between the defect chemistry and the properties of perovskite structure materials, so as to allow the engineering of these materials with the desired properties for the application in industry, such as developing membranes of mixed conductors which have good stability in practical atmospheres. With respect to thermodynamic stability, water solubility limit and mobility of protonic defects the occupation of the A-site does not require much of a compromise. Except for the stability with acidic gases, which is almost independent of the choice of the A-cation, all relevant properties are superior for an A-site occupation by the big barium compared to other alkaline earth ions. Addition of acceptor dopants into ABO3 is crucial to proton uptake. A high concentration of protonic defects requires a high acceptor dopants concentration. Dopants are incorporated into the lattice at either A or B-sites with the respective creation of charge-compensating oxygen vacancies and A-site vacancies. Smaller dopants preferentially substitute at the B-site, while larger cations substitute at the A-site. Partial occupation of the A sublattice can explain the low uptake of protons. The yttrium seems to be perfect acceptor dopant choice for BaZrO3, BaCeO3-based materials, and both the proton mobility and the thermodynamics of hydration are practically unchanged for dopant levels up to 20% Y. The choice of the B-cation, however, requires some compromising. It should be of medium size. High packing densities as a result of small B-cations reduce the water solubility limit, while though the high proton mobilities are compatible with loosely packed structure; the poor compatibility of big B-cations with the perovskite structure reduces the thermodynamic stability including the stability in acidic gases. Empirically high chemical stability and high proton conductivity still seem to exclude one another for simple alkaline earth perovskites. But there is seemingly still room for discoveries among 'old and new' oxide material. We are investigating various possible alternatives to BCY based on the understanding of defect chemistry of doped perovskite structure materials. BCY20 is one of the best proton conductors among this class of conductors, however, not stable in the CO2, H2O-containing atmospheres. In contrast, yttrium-doped barium zirconates have good chemical stability but are undesirable because of their relatively low conductivity and high sintering temperature. Since BaCeO3 and BaZrO3 can easily form solid solutions, it is possible to replace any desired fraction of the Ce in BaCeO3 with Zr, and the solid solution between cerate and zirconate has both high protonic conductivity and good chemical stability. BZCY proton conductors with various compositions (0.0≤x≤0.8) have been synthesized and characterized. The absence of low-angle supercell reflections indicates a random B-site cation distribution. The substitution of Zr led to a decrease in cell volume and an enhanced structural stability against reactions with CO2. The total conductivity for BZCY pellets of all composition increased with temperature increased and decreased as the zirconium content increased from 10% to 40% at each fixed temperature in wet 4% H2/N2 atmosphere. BZCY7 [Ba(Zr0.1Ce 0.7Y0.2)O3] showed pronounced proton conduction within the bulk and along the grain boundaries. Total conductivity increased from 0.015 S/cm at 550°C to 0.043 S/cm at 850°C for BZCY7 smaple, which is highest among all Ba(Zr0.8-xCexY0.2)O 3 (0.4≤x≤0.7) compositions. However, the relatively low electronic conductivity is not adequate for the hydrogen separation membrane to be used in a non-galvanic operation mode, electronic conduction must been introduced into the proton conductor to create mixed ionic-electronic conductors. Dense Ni-BZCY [Ni-Ba(Zr0.8-xCexY0.2)O 3-alpha] cermet composite membranes have been successfully fabricated for evaluating hydrogen permeability, and stability. Nickel phase enhances the hydrogen permeability of the ceramic phase by increasing the electronic conductivity of the composite, surface exchange kinetics, and improving mechanical stability. By comparing the BEI images of BZCY cermets with different Zirconium content, we can tell the grain size, shape and distribution of two phases are insensitive to the zirconium content. Doping Zirconium in the B-site only slightly reduced the hydrogen permeation at high temperatures (e.g. 900°C), but dramatically increased the chemical stability in CO2- and H2O-containing gases. The hydrogen permeation fluxes of Ni-BZCY cermet membrane increased with temperature for all the compositions and the flux decreased as the zirconium content increased at each fixed temperature, but they are comparable to that of Ni-BCY for the lower zirconium content samples (x=0.6, 0.7). While the hydrogen permeation flux through a Ni-BCY cermet membrane decreased sharply upon exposure to wet CO2 atmospheres, the hydrogen permeation flux of a Ni-BZCY was relatively stable for 80 h in atmospheres containing up to 30% CO2 at 900°C after a small initial decrease. Among the compositions studied (0.4≤x≤0.7), the Ni-BZCY7 (x=0.7) composition exhibited both highest H2 permeation rate and good chemistry stability, thus having potential for practical applications. The Ni-BZCY7 membrane was chose to further study based on the best overall performance. The hydrogen flux through a Ni-BZCY7 cermet membrane increased with temperature under both dry and wet conditions. The fact of increasing hydrogen flux by adding moisture to the feed gas or increasing the hydrogen partial pressure gradient across the membrane implies that the hydrogen flux through the Ni-BZCY7 cermet membrane is limited by the proton transport through the ceramic BZCY7 phase. The dependence of hydrogen flux on membrane thickness indicates that the flux is limited by the bulk diffusion of hydrogen through the ceramic phase over the range of thicknesses that were studied (0.25-1.0 mm). Although interfacial reactions are expected to become important for thinner membranes, these results suggest that we can further increase the hydrogen flux by decreasing the membrane thickness. The highest measured hydrogen flux was 0.805 cm3/min-cm 2 for a dense 266-mum-thick membrane at 900°C using 100% H 2 as the feed gas. The hydrogen fluxes through membrane were stable, after a small initial decrease, for 80 h in atmospheres containing up to 30% CO2 at 900°C, implying that Ni-BZCY7 membranes might be suitable for practical applications.

Calculation of ionized fields in DC electrostatic precipitators in the presence of dust and electric wind

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

Cristina, S.; Feliziani, M.

1995-11-01

This paper describes a new procedure for the numerical computation of the electric field and current density distributions in a dc electrostatic precipitator in the presence of dust, taking into account the particle-size distribution. Poisson`s and continuity equations are numerically solved by supposing that the coronating conductors satisfy Kaptzov`s assumption on the emitter surfaces. Two iterative numerical procedures, both based on the finite element method (FEM), are implemented for evaluating, respectively, the unknown ionic charge density and the particle charge density distributions. The V-I characteristic and the precipitation efficiencies for the individual particle-size classes, calculated with reference to the pilotmore » precipitator installed by ENEL (Italian Electricity Board) at its Marghera (Venice) coal-fired power station, are found to be very close to those measured experimentally.« less

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

NASA Astrophysics Data System (ADS)

Lemont, S.; Billaud, D.

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

Study on the Lattice Dynamics of the Argyrodite Ag8GeTe6

NASA Astrophysics Data System (ADS)

Hitchcock, Dale; Thompson, Emily; He, Jian; Bredesen, Isaac; Keppends, Veelre; Mandrus, David

2014-03-01

Ag8GeTe6 was initially studied as a super ionic-electronic mixed conductor in the 1970s, and more recently has attracted new interest for its thermoelectric performance. A key to the desirable thermoelectric performance of Ag8GeTe6 is its exceptionally low lattice thermal conductivity (~ 0.25W/m*K at 300K), which is intimately related to its structure, consecutive structural instabilities, and unusual lattice dynamics (e.g., anharmonicity). In this work, we have studied Ag8GeTe6 by means of thermal conductivity, electrical conductivity, Seebeck coefficient, Hall coefficient, magnetic susceptibility, resonant ultrasound spectroscopy (RUS), photoacoustic spectroscopy, and synchrotron x-ray diffraction at low temperatures in order to further understand the coexistence of mixed conduction and high thermoelectric performance at elevated temperatures. This work is supported by NSF DMR 1307740.

Systematic computational and experimental investigation of lithium-ion transport mechanisms in polyester-based polymer electrolytes

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

Webb, Michael A.; Jung, Yukyung; Pesko, Danielle M.

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds viamore » a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials.« less

Effect of Molecular Weight on the Ion Transport Mechanism in Polymerized Ionic Liquids

DOE PAGES

Fan, Fei; Wang, Weiyu; Holt, Adam P.; ...

2016-06-07

The unique properties of ionic liquids (ILs) have made them promising candidates for electrochemical applications. Polymerization of the corresponding ILs results in a new class of materials called polymerized ionic liquids (PolyILs). Though PolyILs offer the possibility to combine the high conductivity of ILs and the high mechanical strength of polymers, their conductivities are typically much lower than that of the corresponding small molecule ILs. In this study, seven PolyILs were synthesized having degrees of polymerization ranging from 1 to 333, corresponding to molecular weights (MW) from 482 to 160 400 g/mol. Depolarized dynamic light scattering, broadband dielectric spectroscopy, rheology,more » and differential scanning calorimetry were employed to systematically study the influence of MW on the mechanism of ionic transport and segmental dynamics in these materials. Finally, the modified Walden plot analysis reveals that the ion conductivity transforms from being closely coupled with structural relaxation to being strongly decoupled from it as MW increases.« less

Effect of Molecular Weight on the Ion Transport Mechanism in Polymerized Ionic Liquids

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

Fan, Fei; Wang, Weiyu; Holt, Adam P.

The unique properties of ionic liquids (ILs) have made them promising candidates for electrochemical applications. Polymerization of the corresponding ILs results in a new class of materials called polymerized ionic liquids (PolyILs). Though PolyILs offer the possibility to combine the high conductivity of ILs and the high mechanical strength of polymers, their conductivities are typically much lower than that of the corresponding small molecule ILs. In this study, seven PolyILs were synthesized having degrees of polymerization ranging from 1 to 333, corresponding to molecular weights (MW) from 482 to 160 400 g/mol. Depolarized dynamic light scattering, broadband dielectric spectroscopy, rheology,more » and differential scanning calorimetry were employed to systematically study the influence of MW on the mechanism of ionic transport and segmental dynamics in these materials. Finally, the modified Walden plot analysis reveals that the ion conductivity transforms from being closely coupled with structural relaxation to being strongly decoupled from it as MW increases.« less

Systematic computational and experimental investigation of lithium-ion transport mechanisms in polyester-based polymer electrolytes

DOE PAGES

Webb, Michael A.; Jung, Yukyung; Pesko, Danielle M.; ...

2015-07-10

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds viamore » a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials.« less

Systematic Computational and Experimental Investigation of Lithium-Ion Transport Mechanisms in Polyester-Based Polymer Electrolytes

PubMed Central

2015-01-01

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds via a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials. PMID:27162971

Anisotropic amplification of proton transport in proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Thimmappa, Ravikumar; Fawaz, Mohammed; Devendrachari, Mruthyunjayachari Chattanahalli; Gautam, Manu; Kottaichamy, Alagar Raja; Shafi, Shahid Pottachola; Thotiyl, Musthafa Ottakam

2017-07-01

Though graphene oxide (GO) membrane shuttles protons under humid conditions, it suffer severe disintegration and anhydrous conditions lead to abysmal ionic conductivity. The trade-off between mechanical integrity and ionic conductivity challenge the amplification of GO's ionic transport under anhydrous conditions. We show anisotropic amplification of GO's ionic transport with a selective amplification of in plane contribution under anhydrous conditions by doping it with a plant extract, phytic acid (PA). The hygroscopic nature of PA stabilized interlayer water molecules and peculiar geometry of sbnd OH functionalities around saturated hydrocarbon ring anisotropically enhanced ionic transport amplifying the fuel cell performance metrics.

Temperature limited heater utilizing non-ferromagnetic conductor

DOEpatents

Vinegar,; Harold J. , Harris; Kelvin, Christopher [Houston, TX

2012-07-17

A heater is described. The heater includes a ferromagnetic conductor and an electrical conductor electrically coupled to the ferromagnetic conductor. The ferromagnetic conductor is positioned relative to the electrical conductor such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below or near a selected temperature.

Transport and Retention of TiO2 Rutile Nanoparticles in Saturated Porous Media at Low-Ionic-Strength Conditions: Measurements and Mechanisms

EPA Science Inventory

The mechanisms governing the transport and retention kinetics of titanium dioxide (TiO2, rutile) nanoparticle (NP) aggregates were investigated in saturated porous media. Experiments were carried out under a range of well-controlled ionic strength (from DI water up to 1 mM) and...

Theoretical and Numerical Modeling of faceted Ionic crystalline vesicles

NASA Astrophysics Data System (ADS)

Olvera de La Cruz, Monica

2007-03-01

Icosahedral shape is found in several natural structures including large viruses, large fullerenes and cationic-anionic vesicles. Faceting into icosahedral shape can occur in large crystalline membranes via elasticity theory. Icosahedral symmetry is found in small systems of particles with short-range interactions on a sphere. Dr G. Vernizzi and I show a novel electrostatic-driven mechanism of ionic crystalline shells faceting into icosahedral shapes even for systems with a small number of particles. Icosahedral shape is possible in cationic and anionic molecules adsorbed onto spherical interfaces, such as emulsions or other immiscible liquid droplets because the large concentration of charges at the interface can lead to ionic crystals on the curved interface. Such self-organized ionic structures favors the formation of flat surfaces. We find that these ionic crystalline shells can have lower energy when faceted into icosahedra along particular directions. Indeed, the ``ionic'' buckling is driven by preferred bending directions of the planar ionic structure, along which is more likely for the icosahedral shape to develop an edge. Since only certain orientations are allowed, rotational symmetry is broken. One can hope to exploit this mechanism to generate functional materials where, for instance, proteins with specific charge groups can orient at specific directions along an icosahedral cationic-anionic vesicle.

On the relationship between the specific heat enhancement of salt-based nanofluids and the ionic exchange capacity of nanoparticles.

PubMed

Mondragón, Rosa; Juliá, J Enrique; Cabedo, Luis; Navarrete, Nuria

2018-05-14

Nanoparticles have been used in thermal applications to increase the specific heat of the molten salts used in Concentrated Solar Power plants for thermal energy storage. Although several mechanisms for abnormal enhancement have been proposed, they are still being investigated and more research is necessary. However, this nanoparticle-salt interaction can also be found in chemical applications in which nanoparticles have proved suitable to be used as an adsorbent for nitrate removal given their high specific surface, reactivity and ionic exchange capacity. In this work, the ionic exchange capacity mechanism for the nanoparticles functionalization phenomenon was evaluated. The ionic exchange capacity of silica and alumina nanoparticles dispersed in lithium, sodium and potassium nitrates was measured. Fourier-transform infrared spectroscopy tests confirmed the adsorption of nitrate ions on the nanoparticle surface. A relationship between the ionic exchange capacity of nanoparticles and the specific heat enhancement of doped molten salts was proposed for the first time.

Study on Zinc Oxide-Based Electrolytes in Low-Temperature Solid Oxide Fuel Cells

PubMed Central

Qiao, Zheng; Feng, Chu; Wang, Baoyuan; Zhu, Bin

2017-01-01

Semiconducting-ionic conductors have been recently described as excellent electrolyte membranes for low-temperature operation solid oxide fuel cells (LT-SOFCs). In the present work, two new functional materials based on zinc oxide (ZnO)—a legacy material in semiconductors but exceptionally novel to solid state ionics—are developed as membranes in SOFCs for the first time. The proposed ZnO and ZnO-LCP (La/Pr doped CeO2) electrolytes are respectively sandwiched between two Ni0.8Co0.15Al0.05Li-oxide (NCAL) electrodes to construct fuel cell devices. The assembled ZnO fuel cell demonstrates encouraging power outputs of 158–482 mW cm−2 and high open circuit voltages (OCVs) of 1–1.06 V at 450–550 °C, while the ZnO-LCP cell delivers significantly enhanced performance with maximum power density of 864 mW cm−2 and OCV of 1.07 V at 550 °C. The conductive properties of the materials are investigated. As a consequence, the ZnO electrolyte and ZnO-LCP composite exhibit extraordinary ionic conductivities of 0.09 and 0.156 S cm−1 at 550 °C, respectively, and the proton conductive behavior of ZnO is verified. Furthermore, performance enhancement of the ZnO-LCP cell is studied by electrochemical impedance spectroscopy (EIS), which is found to be as a result of the significantly reduced grain boundary and electrode polarization resistances. These findings indicate that ZnO is a highly promising alternative semiconducting-ionic membrane to replace the electrolyte materials for advanced LT-SOFCs, which in turn provides a new strategic pathway for the future development of electrolytes. PMID:29283395

Flexible, solid-state, ion-conducting membrane with 3D garnet nanofiber networks for lithium batteries

PubMed Central

Fu, Kun (Kelvin); Gong, Yunhui; Dai, Jiaqi; Gong, Amy; Han, Xiaogang; Yao, Yonggang; Wang, Chengwei; Wang, Yibo; Chen, Yanan; Yan, Chaoyi; Li, Yiju; Wachsman, Eric D.; Hu, Liangbing

2016-01-01

Beyond state-of-the-art lithium-ion battery (LIB) technology with metallic lithium anodes to replace conventional ion intercalation anode materials is highly desirable because of lithium’s highest specific capacity (3,860 mA/g) and lowest negative electrochemical potential (∼3.040 V vs. the standard hydrogen electrode). In this work, we report for the first time, to our knowledge, a 3D lithium-ion–conducting ceramic network based on garnet-type Li6.4La3Zr2Al0.2O12 (LLZO) lithium-ion conductor to provide continuous Li+ transfer channels in a polyethylene oxide (PEO)-based composite. This composite structure further provides structural reinforcement to enhance the mechanical properties of the polymer matrix. The flexible solid-state electrolyte composite membrane exhibited an ionic conductivity of 2.5 × 10−4 S/cm at room temperature. The membrane can effectively block dendrites in a symmetric Li | electrolyte | Li cell during repeated lithium stripping/plating at room temperature, with a current density of 0.2 mA/cm2 for around 500 h and a current density of 0.5 mA/cm2 for over 300 h. These results provide an all solid ion-conducting membrane that can be applied to flexible LIBs and other electrochemical energy storage systems, such as lithium–sulfur batteries. PMID:27307440

Pushing the Theoretical Limit of Li-CFx Batteries: A Tale of Bi-functional Electrolyte

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

Rangasamy, Ezhiylmurugan; Li, Juchuan; Sahu, Gayatri

2014-01-01

In a typical battery, electrodes deliver capacities less or equal the theoretical maxima of the electrode materials.1 The inert electrolyte functions solely as the ionic conductor without contribution to the cell capacity because of its distinct mono-function in the concept of conventional batteries. Here we demonstrate that the most energy-dense Li-CFx battery2 delivers a capacity exceeding the theoretical maximum of CFx with a solid electrolyte of Li3PS4 (LPS) that has dual functions: as the inert electrolyte at the anode and the active component at the cathode. Such a bi-functional electrolyte reconciles both inert and active characteristics through a synergistic dischargemore » mechanism of CFx and LPS. Li3PS4 is known as an inactive solid electrolyte with a broad electrochemical window over 5 V.3 The synergy at the cathode is through LiF, the discharge product of CFx, which activates the electrochemical discharge of LPS at a close electrochemical potential of CFx. Therefore, the solid-state Li-CFx batteries output 126.6% energy beyond their theoretic limits without compromising the stability of the cell voltage. The extra energy comes from the electrochemical discharge of LPS, the inert electrolyte. This bi-functional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with an unprecedentedly high energy density.« less

Understanding biogeobatteries: Where geophysics meets microbiology

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

Revil, A.; Mendonca, C.A.; Atekwana, E.A.

2009-08-15

Although recent research suggests that contaminant plumes behave as geobatteries that produce an electrical current in the ground, no associated model exists that honors both geophysical and biogeochemical constraints. Here, we develop such a model to explain the two main electrochemical contributions to self-potential signals in contaminated areas. Both contributions are associated with the gradient of the activity of two types of charge carriers, ions and electrons. In the case of electrons, bacteria act as catalysts for reducing the activation energy needed to exchange the electrons between electron donor and electron acceptor. Possible mechanisms that facilitate electron migration include ironmore » oxides, clays, and conductive biological materials, such as bacterial conductive pili or other conductive extracellular polymeric substances. Because we explicitly consider the role of biotic processes in the geobattery model, we coined the term 'biogeobattery'. After theoretical development of the biogeobattery model, we compare model predictions with self-potential responses associated with laboratory and field-scale conducted in contaminated environments. We demonstrate that the amplitude and polarity of large (>100 mV) self-potential signatures requires the presence of an electronic conductor to serve as a bridge between electron donors and acceptors. Small self-potential anomalies imply that electron donors and electron acceptors are not directly interconnected, but instead result simply from the gradient of the activity of the ionic species that are present in the system.« less

Flexible, solid-state, ion-conducting membrane with 3D garnet nanofiber networks for lithium batteries

NASA Astrophysics Data System (ADS)

Kun, Kelvin; Gong, Yunhui; Dai, Jiaqi; Gong, Amy; Han, Xiaogang; Yao, Yonggang; Wang, Chengwei; Wang, Yibo; Chen, Yanan; Yan, Chaoyi; Li, Yiju; Wachsman, Eric D.; Hu, Liangbing

2016-06-01

Beyond state-of-the-art lithium-ion battery (LIB) technology with metallic lithium anodes to replace conventional ion intercalation anode materials is highly desirable because of lithium's highest specific capacity (3,860 mA/g) and lowest negative electrochemical potential (˜3.040 V vs. the standard hydrogen electrode). In this work, we report for the first time, to our knowledge, a 3D lithium-ion-conducting ceramic network based on garnet-type Li6.4La3Zr2Al0.2O12 (LLZO) lithium-ion conductor to provide continuous Li+ transfer channels in a polyethylene oxide (PEO)-based composite. This composite structure further provides structural reinforcement to enhance the mechanical properties of the polymer matrix. The flexible solid-state electrolyte composite membrane exhibited an ionic conductivity of 2.5 × 10-4 S/cm at room temperature. The membrane can effectively block dendrites in a symmetric Li | electrolyte | Li cell during repeated lithium stripping/plating at room temperature, with a current density of 0.2 mA/cm2 for around 500 h and a current density of 0.5 mA/cm2 for over 300 h. These results provide an all solid ion-conducting membrane that can be applied to flexible LIBs and other electrochemical energy storage systems, such as lithium-sulfur batteries.

Sensor apparatus using an electrochemical cell

DOEpatents

Thakur, Mrinal

2003-07-01

A method for sensing mechanical quantities such as force, stress, strain, pressure and acceleration is disclosed. This technology is based on a change in the electrochemically generated voltage (electromotive force) with application of force, stress, strain, pressure or acceleration. The change in the voltage is due to a change in the internal resistance of the electrochemical cell with a change in the relative position or orientation of the electrodes (anode and cathode) in the cell. The signal to be detected (e.g. force, stress, strain, pressure or acceleration) is applied to one of the electrodes to cause a change in the relative position or orientation between the electrodes. Various materials, solid, semisolid, gel, paste or liquid can be utilized as the electrolyte. The electrolyte must be an ion conductor. The examples of solid electrolytes include specific polymer conductors, polymer composites, ion conducting glasses and ceramics. The electrodes are made of conductors such as metals with dissimilar electro negativities. Significantly enhanced sensitivities, up to three orders of magnitude higher than that of comparable commercial sensors, are obtained. The materials are substantially less expensive than commercially used materials for mechanical sensors. An apparatus for sensing such mechanical quantities using materials such as doped 1,4 cis-polyisopropene and nafion. The 1,4 cis-polyisopropene may be doped with lithium perchlorate or iodine. The output voltage signal increases with an increase of the sensing area for a given stress. The device can be used as an intruder alarm, among other applications.

Design of load-to-failure tests of high-voltage insulation breaks for ITER's cryogenic network

NASA Astrophysics Data System (ADS)

Langeslag, S. A. E.; Rodriguez Castro, E.; Aviles Santillana, I.; Sgobba, S.; Foussat, A.

2015-12-01

The development of new generation superconducting magnets for fusion research, such as the ITER experiment, is largely based on coils wound with so-called cable-in-conduit conductors. The concept of the cable-in-conduit conductor is based on a direct cooling principle, by supercritical helium, flowing through the central region of the conductor, in close contact with the superconducting strands. Consequently, a direct connection exists between the electrically grounded helium coolant supply line and the highly energised magnet windings. Various insulated regions, constructed out of high-voltage insulation breaks, are put in place to isolate sectors with different electrical potential. In addition to high voltages and significant internal helium pressure, the insulation breaks will experience various mechanical forces resulting from differential thermal contraction phenomena and electro-magnetic loads. Special test equipment was designed, prepared and employed to assess the mechanical reliability of the insulation breaks. A binary test setup is proposed, where mechanical failure is assumed when leak rate of gaseous helium exceeds 10-9·Pa·m3/s. The test consists of a load-to-failure insulation break charging, in tension, while immersed in liquid nitrogen at the temperature of 77 K. Leak tightness during the test is monitored by measuring the leak rate of the gaseous helium, directly surrounding the insulation break, with respect to the existing vacuum inside the insulation break. The experimental setup is proven effective, and various insulation breaks performed beyond expectations.

Dynamic stress effects in technical superconductors and the ''training'' problem of superconducting magnets

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

Pasztor, G.; Schmidt, C.

The behavior of NbTi superconductors under dynamic mechanical stress was investigated. A training effect was found in short-sample tests when the conductor was strained in a magnetic field and with a transport current applied. Possible mechanisms are discussed which were proposed to explain training in short samples and in magnets. A stress-induced microplastic as well as an incomplete pseudoelastic behavior of NbTi was detected by monitoring acoustic emission. The experiments support the hypothesis that microplastic or shape memory effects in NbTi involving dislocation processes are responsible for training. The minimum energy needed to induce a normal transition in short-sample testsmore » is calculated with a computer program, which gives the exact solution of the heat equation. A prestrain treatment of the conductor at room temperature is shown to be a simple method of reducing training of short samples and of magnets. This is a direct proof that the same mechanisms are involved in both cases.« less

Collapse and pull - down analysis of high voltage electricity transmission towers subjected to cyclonic wind

NASA Astrophysics Data System (ADS)

Ahmed, Ammar; Arthur, Craig; Edwards, Mark

2010-06-01

Bulk electricity transmission lines are linear assets that can be very exposed to wind effects, particularly where they traverse steep topography or open coastal terrain in cyclonic regions. Interconnected nature of the lattice type towers and conductors also, present complex vulnerabilities. These relate to the direction of wind attack to the conductors and the cascading failure mechanisms in which the failure of a single tower has cascading effects on neighbouring towers. Such behaviour is exacerbated by the finely tuned nature of tower design which serves to minimize cost and reserve strength at design wind speeds. There is a clear need to better quantify the interdependent vulnerabilities of these critical infrastructure assets in the context of the severe wind hazard. This paper presents a novel methodology developed for the Critical Infrastructure Protection Modelling and Analysis (CIPMA) capability for assessing local wind speeds and the likelihood of tower failure for a range of transmission tower and conductor types. CIPMA is a program managed by the Federal Attorney-General's Department and Geoscience Australia is leading the technical development. The methodology then involves the development of heuristically derived vulnerability models that are consistent with Australian industry experience and full-scale static tower testing results, considering isolated tower loss along with three interdependent failure mechanisms to give overall likelihoods of failure.

Reliability of ionic polymer metallic composite for opto-mechanical applications

NASA Astrophysics Data System (ADS)

Yu, Chung-Yi; Su, Guo-Dung J.

2014-09-01

Electroactive polymer (EAP) is capable of exhibiting large shape changes in response to electrical stimulation. EAPs can produce large deformation with lower applied voltage for actuation applications. IPMC (Ionic Polymer Metal Composite) is a well-known ionic EAPs. It has numerous attractive advantages, such as low electrical energy consumption and light weight. The mechanism of IPMC actuator is due to the ionic diffusion when the voltage gradient is applied, so that the type of ionic solution has a large impact on the physical properties of IPMC. In this paper, the reliability tests of IPMC with non-aqueous ionic solution are demonstrated. Pt-IPMC with LiOH aqueous solution exhibits the best maximum displacement, but the water in LiOH solution is electrolyzed because of the low electrolysis voltage 1.23 V of water. To improve electrolysis problems and the operation time in the air, proper solvents including high electrolysis voltage and low vapor pressure should be considered. The reliability tests focus on the durability of IPMC in the air. The surface resistance, tip displacement and response time of IPMC are presented. More improvements of IPMC fabrication, such as Ag-IPMC, was developed in this paper.

Dramatic pressure-sensitive ion conduction in conical nanopores.

PubMed

Jubin, Laetitia; Poggioli, Anthony; Siria, Alessandro; Bocquet, Lydéric

2018-04-17

Ion transporters in Nature exhibit a wealth of complex transport properties such as voltage gating, activation, and mechanosensitive behavior. When combined, such processes result in advanced ionic machines achieving active ion transport, high selectivity, or signal processing. On the artificial side, there has been much recent progress in the design and study of transport in ionic channels, but mimicking the advanced functionalities of ion transporters remains as yet out of reach. A prerequisite is the development of ionic responses sensitive to external stimuli. In the present work, we report a counterintuitive and highly nonlinear coupling between electric and pressure-driven transport in a conical nanopore, manifesting as a strong pressure dependence of the ionic conductance. This result is at odds with standard linear response theory and is akin to a mechanical transistor functionality. We fully rationalize this behavior on the basis of the coupled electrohydrodynamics in the conical pore by extending the Poisson-Nernst-Planck-Stokes framework. The model is shown to capture the subtle mechanical balance occurring within an extended spatially charged zone in the nanopore. The pronounced sensitivity to mechanical forcing offers leads in tuning ion transport by mechanical stimuli. The results presented here provide a promising avenue for the design of tailored membrane functionalities.

Reactive solid surface morphology variation via ionic diffusion.

PubMed

Sun, Zhenchao; Zhou, Qiang; Fan, Liang-Shih

2012-08-14

In gas-solid reactions, one of the most important factors that determine the overall reaction rate is the solid morphology, which can be characterized by a combination of smooth, convex and concave structures. Generally, the solid surface structure varies in the course of reactions, which is classically noted as being attributed to one or more of the following three mechanisms: mechanical interaction, molar volume change, and sintering. Here we show that if a gas-solid reaction involves the outward ionic diffusion of a solid-phase reactant then this outward ionic diffusion could eventually smooth the surface with an initial concave and/or convex structure. Specifically, the concave surface is filled via a larger outward diffusing surface pointing to the concave valley, whereas the height of the convex surface decreases via a lower outward diffusion flux in the vertical direction. A quantitative 2-D continuum diffusion model is established to analyze these two morphological variation processes, which shows consistent results with the experiments. This surface morphology variation by solid-phase ionic diffusion serves to provide a fourth mechanism that supplements the traditionally acknowledged solid morphology variation or, in general, porosity variation mechanisms in gas-solid reactions.

Conductor for a fluid-cooled winding

DOEpatents

Kenney, Walter J.

1983-01-01

A conductor and method of making the conductor are provided for use in winding electrical coils which are cooled by a fluid communicating with the conductor. The conductor is cold worked through twisting and reshaping steps to form a generally rectangular cross section conductor having a plurality of helical cooling grooves extending axially of the conductor. The conductor configuration makes it suitable for a wide variety of winding applications and permits the use of simple strip insulation between turns and perforated sheet insulation between layers of the winding.

[Mechanism of action of antiepileptic drugs].

PubMed

Saidón, Patricia

2003-01-01

Antiepileptic drugs (DAEs) act through different mechanisms of action: increase in central inhibition, inhibition of excitatorios mechanisms and modification of the excitability through their action on the ionic channels. Epilepsy is characterized by an abnormal and hypersynchronic unloading of a neuronal population. The activity of numerous drugs is associated to increase in gabaergic activity. Another group of drugs decreases excitatory mechanisms, through the inhibition of ionic channels, or through a decrease in the activity of the excitatory neurotransmitters. There are some of antiepileptic drugs, especially within the group of drugs of recent appearance, for wich the mechanism of action remains unknown.

Simulation of mechano-electrical transduction in the cochlea considering basilar membrane vibration and the ionic current of the inner hair cells

NASA Astrophysics Data System (ADS)

Lee, Sinyoung; Koike, Takuji

2018-05-01

The inner hair cells (IHCs) in the cochlea transduce mechanical vibration of the basilar membrane (BM), caused by sound pressure, to electrical signals that are transported along the acoustic nerve to the brain. The mechanical vibration of the BM and the ionic behaviors of the IHCs have been investigated. However, consideration of the ionic behavior of the IHCs related to mechanical vibration is necessary to investigate the mechano-electrical transduction of the cochlea. In this study, a finite-element model of the BM, which takes into account the non-linear activities of the outer hair cells (OHCs), and an ionic current model of IHC were combined. The amplitudes and phases of the vibration at several points on the BM were obtained from the finite-element model by applying sound pressure. These values were fed into the ionic current model, and changes in membrane potential and calcium ion concentration of the IHCs were calculated. The membrane potential of the IHC at the maximum amplitude point (CF point) was higher than that at the non-CF points. The calcium ion concentration at the CF point was also higher than that at the non-CF points. These results suggest that the cochlea achieves its good frequency discrimination ability through mechano-electrical transduction.

Semi-flexible gas-insulated transmission line using sandwiched discs for intermittent flexing joints

DOEpatents

Kommineni, P.R.

1983-02-15

A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by the use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements are formed by sandwiching together, by fusing, a pair of thin hollow discs which are fixedly secured to both the main conductor sections and the conductor hub section. 4 figs.

Role of Heavy Meromyosin in Heat-Induced Gelation in Low Ionic Strength Solution Containing L-Histidine.

PubMed

Hayakawa, Toru; Yoshida, Yuri; Yasui, Masanori; Ito, Toshiaki; Wakamatsu, Jun-ichi; Hattori, Akihito; Nishimura, Takanori

2015-08-01

The gelation of myosin has a very important role in meat products. We have already shown that myosin in low ionic strength solution containing L-histidine forms a transparent gel after heating. To clarify the mechanism of this unique gelation, we investigated the changes in the nature of myosin subfragments during heating in solutions with low and high ionic strengths with and without L-histidine. The hydrophobicity of myosin and heavy meromyosin (HMM) in low ionic strength solution containing L-histidine was lower than in high ionic strength solution. The SH contents of myosin and HMM in low ionic strength solution containing l-histidine did not change during the heating process, whereas in high ionic strength solution they decreased slightly. The heat-induced globular masses of HMM in low ionic strength solution containing L-histidine were smaller than those in high ionic strength solution. These findings suggested that the polymerization of HMM molecules by heating was suppressed in low ionic strength solution containing L-histidine, resulting in formation of the unique gel. © 2015 Institute of Food Technologists®

Mg2B2O5 Nanowire Enabled Multifunctional Solid-State Electrolytes with High Ionic Conductivity, Excellent Mechanical Properties, and Flame-Retardant Performance.

PubMed

Sheng, Ouwei; Jin, Chengbin; Luo, Jianmin; Yuan, Huadong; Huang, Hui; Gan, Yongping; Zhang, Jun; Xia, Yang; Liang, Chu; Zhang, Wenkui; Tao, Xinyong

2018-05-09

High ionic conductivity, satisfactory mechanical properties, and wide electrochemical windows are crucial factors for composite electrolytes employed in solid-state lithium-ion batteries (SSLIBs). Based on these considerations, we fabricate Mg 2 B 2 O 5 nanowire enabled poly(ethylene oxide) (PEO)-based solid-state electrolytes (SSEs). Notably, these SSEs have enhanced ionic conductivity and a large electrochemical window. The elevated ionic conductivity is attributed to the improved motion of PEO chains and the increased Li migrating pathway on the interface between Mg 2 B 2 O 5 and PEO-LiTFSI. Moreover, the interaction between Mg 2 B 2 O 5 and -SO 2 - in TFSI - anions could also benefit the improvement of conductivity. In addition, the SSEs containing Mg 2 B 2 O 5 nanowires exhibit improved the mechanical properties and flame-retardant performance, which are all superior to the pristine PEO-LiTFSI electrolyte. When these multifunctional SSEs are paired with LiFePO 4 cathodes and lithium metal anodes, the SSLIBs show better rate performance and higher cyclic capacity of 150, 106, and 50 mAh g -1 under 0.2 C at 50, 40, and 30 °C. This strategy of employing Mg 2 B 2 O 5 nanowires provides the design guidelines of assembling multifunctional SSLIBs with high ionic conductivity, excellent mechanical properties, and flame-retardant performance at the same time.

Electromechanical engineering in SnO2 nanoparticle tethered hybrid ionic liquid

NASA Astrophysics Data System (ADS)

Deb, Debalina; Bhattacharya, Subhratanu

2017-05-01

Challenge of developing electrolytes comprising synergic properties of high mechanical strength with superior electrical and electrochemical properties has so far been unmet towards the application of secondary storage devices. In this research, we have engineered the electromechanical properties of 2-(trimethylamino) ethyl methacrylate bis(trifluoromethylsulfonyl) imide [TMEM]TFSI ionic liquid by tethering silane modified SnO2 nanoparticles within it. Different percentages of tethering are employed to achieve improved ionic conductivity, better discharge/ charging ratio (40%) along with gel like mechanical properties. Our findings appear to provide an optimal solution towards the future prospects in application in a number of areas, notably in energy-related technologies.

Electromagnetic energy coupling mechanism with matrix architecture control

NASA Technical Reports Server (NTRS)

Hughes, Eli (Inventor); Knowles, Gareth (Inventor)

2006-01-01

The present invention relates generally to reconfigurable, solid-state matrix arrays comprising multiple rows and columns of reconfigurable secondary mechanisms that are independently tuned. Specifically, the invention relates to reconfigurable devices comprising multiple, solid-state mechanisms characterized by at least one voltage-varied parameter disposed within a flexible, multi-laminate film, which are suitable for use as magnetic conductors, ground surfaces, antennas, varactors, ferrotunable substrates, or other active or passive electronic mechanisms.

Gate-Induced Metal–Insulator Transition in MoS 2 by Solid Superionic Conductor LaF 3

DOE PAGES

Wu, Chun-Lan; Yuan, Hongtao; Li, Yanbin; ...

2018-03-23

Electric-double-layer (EDL) gating with liquid electrolyte has been a powerful tool widely used to explore emerging interfacial electronic phenomena. Due to the large EDL capacitance, a high carrier density up to 10 14 cm –2 can be induced, directly leading to the realization of field-induced insulator to metal (or superconductor) transition. However, the liquid nature of the electrolyte has created technical issues including possible side electrochemical reactions or intercalation, and the potential for huge strain at the interface during cooling. In addition, the liquid coverage of active devices also makes many surface characterizations and in situ measurements challenging. Here, wemore » demonstrate an all solid-state EDL device based on a solid superionic conductor LaF 3, which can be used as both a substrate and a fluorine ionic gate dielectric to achieve a wide tunability of carrier density without the issues of strain or electrochemical reactions and can expose the active device surface for external access. Based on LaF 3 EDL transistors (EDLTs), we observe the metal–insulator transition in MoS 2. Interestingly, the well-defined crystal lattice provides a more uniform potential distribution in the substrate, resulting in less interface electron scattering and therefore a higher mobility in MoS 2 transistors. Finally, this result shows the powerful gating capability of LaF 3 solid electrolyte for new possibilities of novel interfacial electronic phenomena.« less

46 CFR 111.05-33 - Equipment safety grounding (bonding) conductors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Equipment safety grounding (bonding) conductors. 111.05... § 111.05-33 Equipment safety grounding (bonding) conductors. (a) Each equipment-grounding conductor must... 110.10-1). (b) Each equipment-grounding conductor (other than a system-grounding conductor) of a cable...

46 CFR 111.05-33 - Equipment safety grounding (bonding) conductors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Equipment safety grounding (bonding) conductors. 111.05... § 111.05-33 Equipment safety grounding (bonding) conductors. (a) Each equipment-grounding conductor must... 110.10-1). (b) Each equipment-grounding conductor (other than a system-grounding conductor) of a cable...

Semi-flexible gas-insulated transmission line using protection tube in conductor plug-in joint

DOEpatents

Kommineni, P.R.

1983-01-25

A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. A plug and socket arrangement is utilized for joining adjacent sections of the inner conductor, and a protection tube is utilized inside the hollow plug to maintain proper alignment of the joint when the transmission line is bent. 3 figs.

Semi-flexible gas-insulated transmission line using protection tube in conductor plug-in joint

DOEpatents

Kommineni, Prasad R.

1983-01-25

A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. A plug and socket arrangement is utilized for joining adjacent sections of the inner conductor, and a protection tube is utilized inside the hollow plug to maintain proper alignment of the joint when the transmission line is bent.

Terminal structure

DOEpatents

Schmidt, Frank [Langenhagen, DE; Allais, Arnaud [Hannover, DE; Mirebeau, Pierre [Villebon sur Yvette, FR; Ganhungu, Francois [Vieux-Reng, FR; Lallouet, Nicolas [Saint Martin Boulogne, FR

2009-10-20

A terminal structure (2) for a superconducting cable (1) is described. It consists of a conductor (2a) and an insulator (2b) that surrounds the conductor (2a), wherein the superconducting cable (1) has a core with a superconducting conductor (5) and a layer of insulation that surrounds the conductor (5), and wherein the core is arranged in such a way that it can move longitudinally in a cryostat. The conductor (2a) of the terminal structure (2) is electrically connected with the superconducting conductor (5) or with a normal conductor (6) that is connected with the superconducting conductor (5) by means of a tubular part (7) made of an electrically conductive material, wherein the superconducting conductor (5) or the normal conductor (6) can slide in the part (7) in the direction of the superconductor.

Ion Transport and Structural Properties of Polymeric Electrolytes and Ionic Liquids from Molecular Dynamics Simulations

NASA Astrophysics Data System (ADS)

Borodin, Oleg

2010-03-01

Molecular dynamics simulations are well suited for exploring electrolyte structure and ion transport mechanisms on the nanometer length scale and the nanosecond time scales. In this presentation we will describe how MD simulations assist in answering fundamental questions about the lithium transport mechanisms in polymeric electrolytes and ionic liquids. In particular, in the first part of the presentation the extent of ion aggregation, the structure of ion aggregates and the lithium cation diffusion in binary polymeric electrolytes will be compared with that of single-ion conducting polymers. In the second part of the talk, the lithium transport in polymeric electrolytes will be compared with that of three ionic liquids ( [emim][FSI] doped with LiFSI , [pyr13][FSI] doped with LiFSI, [emim][BF4] doped with LiBF4). The relation between ionic liquid self-diffusion, conductivity and thermodynamic properties will be discussed in details. A number of correlations between heat of vaporization Hvap, cation-anion binding energy (E+/-), molar volume (Vm), self-diffusion coefficient (D) and ionic conductivity for 29 ionic liquids have been investigated using MD simulations. A significant correlation between D and Hvap has been found, while best correlation was found for -log((D Vm)) vs. Hvap+0.28E+/-. A combination of enthalpy of vaporization and a fraction of the cation-anion binding energy was suggested as a measure of the effective cohesive energy for ionic liquids.

Critical current survival in the YBCO superconducting layer of a delaminated coated conductor

NASA Astrophysics Data System (ADS)

Feng, Feng; Fu, Qishu; Qu, Timing; Mu, Hui; Gu, Chen; Yue, Yubin; Wang, Linli; Yang, Zhirong; Han, Zhenghe; Feng, Pingfa

2018-04-01

A high-temperature superconducting coated conductor can be practically applied in electric equipment due to its favorable mechanical properties and critical current (I c) performance. However, the coated conductor can easily delaminate because of its poor stress tolerance along the thickness direction. It would be interesting to investigate whether the I c of the delaminated YBa2Cu3O7-δ (YBCO) layer can be preserved. In this study, coated conductor samples manufactured through the metal organic deposition route were delaminated by liquid nitrogen immersion. Delaminated samples, including the YBCO layer and silver stabilizer, were obtained. Delamination occurred inside the YBCO layer and near the YBCO-CeO2 interface, as suggested by the results of scanning electron microscopy (SEM) and x-ray diffraction. A scanning Hall probe system was employed to measure the I c distribution of the original sample and the delaminated sample. It was found that approximately 50% of the I c can be preserved after delamination, which was verified by I c measurements using the four-probe method. Dense and crack-free morphologies of the delaminated surfaces were observed by SEM, which accounts for the I c survival of the delaminated YBCO layer. The potential application of the delaminated sample in superconducting joints was discussed based on the oxygen diffusion estimation.

Recent Progress on Stretchable Electronic Devices with Intrinsically Stretchable Components.

PubMed

Trung, Tran Quang; Lee, Nae-Eung

2017-01-01

Stretchable electronic devices with intrinsically stretchable components have significant inherent advantages, including simple fabrication processes, a high integrity of the stacked layers, and low cost in comparison with stretchable electronic devices based on non-stretchable components. The research in this field has focused on developing new intrinsically stretchable components for conductors, semiconductors, and insulators. New methodologies and fabrication processes have been developed to fabricate stretchable devices with intrinsically stretchable components. The latest successful examples of stretchable conductors for applications in interconnections, electrodes, and piezoresistive devices are reviewed here. Stretchable conductors can be used for electrode or sensor applications depending on the electrical properties of the stretchable conductors under mechanical strain. A detailed overview of the recent progress in stretchable semiconductors, stretchable insulators, and other novel stretchable materials is also given, along with a discussion of the associated technological innovations and challenges. Stretchable electronic devices with intrinsically stretchable components such as field-effect transistors (FETs), photodetectors, light-emitting diodes (LEDs), electronic skins, and energy harvesters are also described and a new strategy for development of stretchable electronic devices is discussed. Conclusions and future prospects for the development of stretchable electronic devices with intrinsically stretchable components are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Artificial perfect electric conductor-perfect magnetic conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency

NASA Astrophysics Data System (ADS)

Chen, Menglin L. N.; Jiang, Li Jun; Sha, Wei E. I.

2016-02-01

Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect electric conductor-perfect magnetic conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of electric field, the continuous metasurface shows very smooth phase pattern at the near-field region, which cannot be achieved by convectional metasurfaces composed of discrete scatterers. On the other hand, the metasurface with discrete dipole scatterers shows a great flexibility to generate OAM with arbitrary topological charges. Our work is fundamentally and practically important to high-performance OAM generation.

Enhancement of Force Generated by Individual Myosin Heads in Skinned Rabbit Psoas Muscle Fibers at Low Ionic Strength

PubMed Central

Sugi, Haruo; Abe, Takahiro; Kobayashi, Takakazu; Chaen, Shigeru; Ohnuki, Yoshiki; Saeki, Yasutake; Sugiura, Seiryo

2013-01-01

Although evidence has been presented that, at low ionic strength, myosin heads in relaxed skeletal muscle fibers form linkages with actin filaments, the effect of low ionic strength on contraction characteristics of Ca2+-activated muscle fibers has not yet been studied in detail. To give information about the mechanism of muscle contraction, we have examined the effect of low ionic strength on the mechanical properties and the contraction characteristics of skinned rabbit psoas muscle fibers in both relaxed and maximally Ca2+-activated states. By progressively decreasing KCl concentration from 125 mM to 0 mM (corresponding to a decrease in ionic strength μ from 170 mM to 50 mM), relaxed fibers showed changes in mechanical response to sinusoidal length changes and ramp stretches, which are consistent with the idea of actin-myosin linkage formation at low ionic strength. In maximally Ca2+-activated fibers, on the other hand, the maximum isometric force increased about twofold by reducing KCl concentration from 125 to 0 mM. Unexpectedly, determination of the force-velocity curves indicated that, the maximum unloaded shortening velocity Vmax, remained unchanged at low ionic strength. This finding indicates that the actin-myosin linkages, which has been detected in relaxed fibers at low ionic strength, are broken quickly on Ca2+ activation, so that the linkages in relaxed fibers no longer provide any internal resistance against fiber shortening. The force-velocity curves, obtained at various levels of steady Ca2+-activated isometric force, were found to be identical if they are normalized with respect to the maximum isometric force. The MgATPase activity of muscle fibers during isometric force generation was found not to change appreciably at low ionic strength despite the two-fold increase in Ca2+-activated isometric force. These results can be explained in terms of enhancement of force generated by individual myosin heads, but not by any changes in kinetic properties of cyclic actin-myosin interaction. PMID:23691080

Formation of p-n-p junction with ionic liquid gate in graphene

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

He, Xin; Tang, Ning, E-mail: ntang@pku.edu.cn, E-mail: geweikun@mail.tsinghua.edu.cn, E-mail: bshen@pku.edu.cn; Duan, Junxi

2014-04-07

Ionic liquid gating is a technique which is much more efficient than solid gating to tune carrier density. To observe the electronic properties of such a highly doped graphene device, a top gate made of ionic liquid has been used. By sweeping both the top and back gate voltage, a p-n-p junction has been created. The mechanism of forming the p-n-p junction has been discussed. Tuning the carrier density by ionic liquid gate can be an efficient method to be used in flexible electronics.

Semi-flexible gas-insulated transmission line using electric field stress shields

DOEpatents

Cookson, Alan H.; Dale, Steinar J.; Bolin, Philip C.

1982-12-28

A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements and the stress shields may also be utilized in connection with a plug and socket arrangement for providing electrical connection between main conductor sections.

Solid-state proton conductors

NASA Astrophysics Data System (ADS)

Jewulski, J. R.; Osif, T. L.; Remick, R. J.

1990-12-01

The purpose of this program was to survey the field of solid-state proton conductors (SSPC), identify conductors that could be used to develop solid-state fuel cells suitable for use with coal derived fuel gases, and begin the experimental research required for the development of these fuel cells. This document covers the following topics: the history of developments and current status of the SSPC, including a review of proton conducting electrolyte structures, the current status of the medium temperature SSPC development, electrodes for moderate temperature (SSPC) fuel cell, basic material and measurement techniques applicable for SSPC development, modeling, and optimization studies. Correlation and optimization studies are described which include correlation studies on proton conduction and oxide cathode optimization for the SSPC fuel cell. Experiments with the SSPC fuel cells are presented which include the fabrication of the electrolyte disks, apparatus for conducting measurements, the strontium-cerium based electrolyte, the barium-cerium based electrolyte with solid foil electrodes, the barium-cerium based electrolyte with porous electrodes, and conduction mechanisms.

Method for transferring thermal energy and electrical current in thin-film electrochemical cells

DOEpatents

Rouillard, Roger [Beloeil, CA; Domroese, Michael K [South St. Paul, MN; Hoffman, Joseph A [Minneapolis, MN; Lindeman, David D [Hudson, WI; Noel, Joseph-Robert-Gaetan [St-Hubert, CA; Radewald, Vern E [Austin, TX; Ranger, Michel [Lachine, CA; Sudano, Anthony [Laval, CA; Trice, Jennifer L [Eagan, MN; Turgeon, Thomas A [Fridley, MN

2003-05-27

An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

Low-Cost Manufacturing of Bioresorbable Conductors by Evaporation-Condensation-Mediated Laser Printing and Sintering of Zn Nanoparticles.

PubMed

Shou, Wan; Mahajan, Bikram K; Ludwig, Brandon; Yu, Xiaowei; Staggs, Joshua; Huang, Xian; Pan, Heng

2017-07-01

Currently, bioresorbable electronic devices are predominantly fabricated by complex and expensive vacuum-based integrated circuit (IC) processes. Here, a low-cost manufacturing approach for bioresorbable conductors on bioresorbable polymer substrates by evaporation-condensation-mediated laser printing and sintering of Zn nanoparticle is reported. Laser sintering of Zn nanoparticles has been technically difficult due to the surface oxide on nanoparticles. To circumvent the surface oxide, a novel approach is discovered to print and sinter Zn nanoparticle facilitated by evaporation-condensation in confined domains. The printing process can be performed on low-temperature substrates in ambient environment allowing easy integration on a roll-to-roll platform for economical manufacturing of bioresorbable electronics. The fabricated Zn conductors show excellent electrical conductivity (≈1.124 × 10 6 S m -1 ), mechanical durability, and water dissolvability. Successful demonstration of strain gauges confirms the potential application in various environmentally friendly sensors and circuits. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of flower-like Boehmite (γ-AlOOH) via a one-step ionic liquid-assisted hydrothermal route

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

Tang, Zhe, E-mail: tangzhe1983@163.com; Liang, Jilei, E-mail: liangjilei_httplan@126.com; Li, Xuehui, E-mail: lxhhmx@163.com

A simple and novel synthesis process, one-step ionic liquid-assisted hydrothermal synthesis route, has been developed in the work to synthesize Bohemithe (γ-AlOOH) with flower-like structure. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM). Ionic liquid [Omim]{sup +}Cl{sup −}, as a template, plays an important role in the morphology and pore structure of the products due to its strong interactions with reaction particles. With the increase in the dosage of ionic liquid [Omim]{sup +}Cl{sup −}, the morphology of the γ-AlOOH was changed from initial bundles of nanosheets (without ionic liquid) intomore » final well-developed monodispersed 3D flower-like architectures ([Omim]{sup +}Cl{sup −}=72 mmol). The pore structure was also altered gradually from initial disordered slit-like pore into final relatively ordered ink-bottle pore. Furthermore, the proposed formation mechanism and other influencing factors such as reaction temperature and urea on formation and morphology of the γ-AlOOH have also been investigated. - Graphical abstract: The flower-like γ-AlOOH architectures composed by nanosheets with narrow size distribution (1.6–2.2 μm) and uniform pore size (6.92 nm) have been synthesized via a one-step ionic liquid-assisted hydrothermal route. - Highlights: • The γ-AlOOH microflowers were synthesized via an ionic liquid-assisted hydrothermal route. • Ionic liquid plays an important role on the morphology and porous structure of the products. • Ionic liquid can be easily removed from the products and reused in recycling experiments. • A “aggregation–recrystallization–Ostwald Ripening“formation mechanism may occur.« less

Conductor and joint test results of JT-60SA CS and EF coils using the NIFS test facility

NASA Astrophysics Data System (ADS)

Obana, Tetsuhiro; Takahata, Kazuya; Hamaguchi, Shinji; Kizu, Kaname; Murakami, Haruyuki; Chikaraishi, Hirotaka; Noguchi, Hiroki; Kobuchi, Takashi; Moriuchi, Sadatomo; Imagawa, Shinsaku; Mito, Toshiyuki; Tsuchiya, Katsuhiko; Natsume, Kyohei; Yoshida, Kiyoshi; Nomoto, Kazuhiro; Kim, Tae-hyun

2016-01-01

In 2007, JAEA and NIFS launched the test project to evaluate the performance of cable-in-conduit (CIC) conductors and conductor joints for the JT-60SA CS and EF coils. In this project, conductor tests for four types of coil conductor and joint tests for seven types of conductor joint have been conducted for the past eight years using the NIFS test facility. As a result, the test project indicated that the CIC conductors and conductor joints fulfill the design requirement for the CS and EF coils. In addition, the NIFS test facility is expected to be utilized as the test facility for the development of a conductor and conductor joint for the purpose of the DEMO nuclear fusion power plant, provided that the required magnetic field strength is within 9 T.

The Shock and Vibration Digest. Volume 18, Number 11

DTIC Science & Technology

1986-11-01

instantaneous clearances for various conductor loadings and weather conditions. Composite insulators are now more widely used. They consists...ter under gunfire. However, their electrical and mechanical behaviors are mote complicated than those of analogous porcelain insulators because...mechanical considerations by discussing recent research papets. Tensile tests on composite insulators have shown that short-term tensile

Nanoengineered Ionic-Covalent Entanglement (NICE) Bioinks for 3D Bioprinting.

PubMed

Chimene, David; Peak, Charles W; Gentry, James L; Carrow, James K; Cross, Lauren M; Mondragon, Eli; Cardoso, Guinea B; Kaunas, Roland; Gaharwar, Akhilesh K

2018-03-28

We introduce an enhanced nanoengineered ionic-covalent entanglement (NICE) bioink for the fabrication of mechanically stiff and elastomeric 3D biostructures. NICE bioink formulations combine nanocomposite and ionic-covalent entanglement (ICE) strengthening mechanisms to print customizable cell-laden constructs for tissue engineering with high structural fidelity and mechanical stiffness. Nanocomposite and ICE strengthening mechanisms complement each other through synergistic interactions, improving mechanical strength, elasticity, toughness, and flow properties beyond the sum of the effects of either reinforcement technique alone. Herschel-Bulkley flow behavior shields encapsulated cells from excessive shear stresses during extrusion. The encapsulated cells readily proliferate and maintain high cell viability over 120 days within the 3D-printed structure, which is vital for long-term tissue regeneration. A unique aspect of the NICE bioink is its ability to print much taller structures, with higher aspect ratios, than can be achieved with conventional bioinks without requiring secondary supports. We envision that NICE bioinks can be used to bioprint complex, large-scale, cell-laden constructs for tissue engineering with high structural fidelity and mechanical stiffness for applications in custom bioprinted scaffolds and tissue engineered implants.

Mathematical modeling of electrical activity of uterine muscle cells.

PubMed

Rihana, Sandy; Terrien, Jeremy; Germain, Guy; Marque, Catherine

2009-06-01

The uterine electrical activity is an efficient parameter to study the uterine contractility. In order to understand the ionic mechanisms responsible for its generation, we aimed at building a mathematical model of the uterine cell electrical activity based upon the physiological mechanisms. First, based on the voltage clamp experiments found in the literature, we focus on the principal ionic channels and their cognate currents involved in the generation of this electrical activity. Second, we provide the methodology of formulations of uterine ionic currents derived from a wide range of electrophysiological data. The model is validated step by step by comparing simulated voltage-clamp results with the experimental ones. The model reproduces successfully the generation of single spikes or trains of action potentials that fit with the experimental data. It allows analyzing ionic channels implications. Likewise, the calcium-dependent conductance influences significantly the cellular oscillatory behavior.

[Trophoblast: conductor of the maternal immune tolerance].

PubMed

Mesdag, V; Salzet, M; Vinatier, D

2014-11-01

Pregnancy is a temporary semi-allograft that survives for nine months. The importance of this event for the survival of the species justifies several tolerance mechanisms that are put into place at the beginning of pregnancy, some of which occur even at the time of implantation. The description of these mechanisms underlines the leadership of the trophoblast. The trophoblast is the conductor of the events, protects himself by expressing specific antigens and regulates the environment of the decidua according to the calendar of the events of the pregnancy The trophoblast and the decidual environment attract the effectors of immunity, almost all present in the decidua. The immunological atmosphere of the decidua evolves during the pregnancy modulating the level of activation of the immunological cells and adapting the level of activation to the stage of the pregnancy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Active chemisorption sites in functionalized ionic liquids for carbon capture.

PubMed

Cui, Guokai; Wang, Jianji; Zhang, Suojiang

2016-07-25

Development of novel technologies for the efficient and reversible capture of CO2 is highly desired. In the last decade, CO2 capture using ionic liquids has attracted intensive attention from both academia and industry, and has been recognized as a very promising technology. Recently, a new approach has been developed for highly efficient capture of CO2 by site-containing ionic liquids through chemical interaction. This perspective review focuses on the recent advances in the chemical absorption of CO2 using site-containing ionic liquids, such as amino-based ionic liquids, azolate ionic liquids, phenolate ionic liquids, dual-functionalized ionic liquids, pyridine-containing ionic liquids and so on. Other site-containing liquid absorbents such as amine-based solutions, switchable solvents, and functionalized ionic liquid-amine blends are also investigated. Strategies have been discussed for how to activate the existent reactive sites and develop novel reactive sites by physical and chemical methods to enhance CO2 absorption capacity and reduce absorption enthalpy. The carbon capture mechanisms of these site-containing liquid absorbents are also presented. Particular attention has been paid to the latest progress in CO2 capture in multiple-site interactions by amino-free anion-functionalized ionic liquids. In the last section, future directions and prospects for carbon capture by site-containing ionic liquids are outlined.

Simulation study of the lithium ion transport mechanism in ternary polymer electrolytes: the critical role of the segmental mobility.

PubMed

Diddens, Diddo; Heuer, Andreas

2014-01-30

We present an extensive molecular dynamics (MD) simulation study of the lithium ion transport in ternary polymer electrolytes consisting of poly(ethylene oxide) (PEO), lithium-bis(trifluoromethane)sulfonimide (LiTFSI), and the ionic liquid N-methyl-N-propylpyrrolidinium bis(trifluoromethane)sulfonimide (PYR13TFSI). In particular, we focus on two different strategies by which the ternary electrolytes can be devised, namely by (a) adding the ionic liquid to PEO20LiTFSI and (b) substituting the PEO chains in PEO20LiTFSI by the ionic liquid. To grasp the changes of the overall lithium transport mechanism, we employ an analytical, Rouse-based cation transport model (Maitra et al. Phys. Rev. Lett. 2007, 98, 227802), which has originally been devised for binary PEO-based electrolytes. This model distinguishes three different microscopic transport mechanisms, each quantified by an individual time scale. In the course of our analysis, we extend this mathematical description to account for an entirely new transport mechanism, namely, the TFSI-supported diffusion of lithium ions decoupled from the PEO chains, which emerges for certain stoichiometries. We find that the segmental mobility plays a decisive role in PEO-based polymer electrolytes. That is, whereas the addition of the ionic liquid to PEO20LiTFSI plasticizes the polymer network and thus also increases the lithium diffusion, the amount of free, mobile ether oxygens reduces when substituting the PEO chains by the ionic liquid, which compensates the plasticizing effect. In total, our observations allow us to formulate some general principles about the lithium ion transport mechanism in ternary polymer electrolytes. Moreover, our insights also shed light on recent experimental observations (Joost et al. Electrochim. Acta 2012, 86, 330).

Development of ionic gels using thiol-based monomers in ionic liquid

NASA Astrophysics Data System (ADS)

Ahmed, Kumkum; Naga, Naofumi; Kawakami, Masaru; Furukawa, Hidemitsu

2016-04-01

Ionic gels (IGs) using ionic liquids (ILs) can propose diverse applications in the field of optics, sensors and separation have opened wide prospects in materials science. ILs have attracted remarkable interest for gel polymer electrolytes and batteries based on their useful properties such as non-volatility, non-flammability, a wide electrochemical window, high thermal stability and a high ionic conductivity. The formation of gel in IL media makes it possible to immobilize ILs within organic or inorganic matrices and to take advantage of their unique properties in the solid state, thus eliminating some shortcomings related to shaping and risk of leakage. In this work for the first time we used multifunctional thiol monomers having uniform structure and good compatibility with the IL of our interest. Therefore we focused on developing thiol monomer-based IGs using multifunctional thiol monomers and acrylate crosslinkers utilizing thiol-ene reaction between monomer and crosslinking molecules in an IL medium and characterize their physico-chemical properties like thermal, conductive, mechanical properties etc.. This work has been focused mainly to improve the mechanical strength of IGs and make prospects of IGs in tribology and lubricants.

Simulating chemical reactions in ionic liquids using QM/MM methodology.

PubMed

Acevedo, Orlando

2014-12-18

The use of ionic liquids as a reaction medium for chemical reactions has dramatically increased in recent years due in large part to the numerous reported advances in catalysis and organic synthesis. In some extreme cases, ionic liquids have been shown to induce mechanistic changes relative to conventional solvents. Despite the large interest in the solvents, a clear understanding of the molecular factors behind their chemical impact is largely unknown. This feature article reviews our efforts developing and applying mixed quantum and molecular mechanical (QM/MM) methodology to elucidate the microscopic details of how these solvents operate to enhance rates and alter mechanisms for industrially and academically important reactions, e.g., Diels-Alder, Kemp eliminations, nucleophilic aromatic substitutions, and β-eliminations. Explicit solvent representation provided the medium dependence of the activation barriers and atomic-level characterization of the solute-solvent interactions responsible for the experimentally observed "ionic liquid effects". Technical advances are also discussed, including a linear-scaling pairwise electrostatic interaction alternative to Ewald sums, an efficient polynomial fitting method for modeling proton transfers, and the development of a custom ionic liquid OPLS-AA force field.

Thermal conductor for high-energy electrochemical cells

DOEpatents

Hoffman, Joseph A.; Domroese, Michael K.; Lindeman, David D.; Radewald, Vern E.; Rouillard, Roger; Trice, Jennifer L.

2000-01-01

A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

Preparation of metallic cation conducting polymers based on sterically hindered phenols containing polymeric systems

DOEpatents

Skotheim, Terje A.; Okamoto, Yoshiyuki; Lee, Hung S.

1989-01-01

The present invention relates to ion-conducting solvent-free polymeric systems characterized as being cationic single ion conductors. The solvent-free polymer electrolytes comprise a flexible polymer backbone to which is attached a metal salt, such as a lithium, sodium or potassium salt, of a sterically hindered phenol. The solid polymer electrolyte may be prepared either by (1) attaching the hindered phenol directly to a flexible polymeric backbone, followed by neutralization of the phenolic OH's or (2) reacting the hindered phenol with a polymer precursor which is then polymerized to form a flexible polymer having phenolic OH's which are subsequently neutralized. Preferably the hindered phenol-modified polymeric backbone contains a polyether segment. The ionic conductivity of these solvent-free polymer electrolytes has been measured to be in the range of 10.sup.-4 to 10.sup.-7 S cm.sup.-1 at room temperature.

Preparation of metallic cation conducting polymers based on sterically hindered phenols containing polymeric systems

DOEpatents

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

1989-11-21

The present invention relates to ion-conducting solvent-free polymeric systems characterized as being cationic single ion conductors. The solvent-free polymer electrolytes comprise a flexible polymer backbone to which is attached a metal salt, such as a lithium, sodium or potassium salt, of a sterically hindered phenol. The solid polymer electrolyte may be prepared either by (1) attaching the hindered phenol directly to a flexible polymeric backbone, followed by neutralization of the phenolic OH's or (2) reacting the hindered phenol with a polymer precursor which is then polymerized to form a flexible polymer having phenolic OH's which are subsequently neutralized. Preferably the hindered phenol-modified polymeric backbone contains a polyether segment. The ionic conductivity of these solvent-free polymer electrolytes has been measured to be in the range of 10[sup [minus]4] to 10[sup [minus]7] S cm[sup [minus]1] at room temperature.

Direct laser writing of micro-supercapacitors on hydrated graphite oxide films.

PubMed

Gao, Wei; Singh, Neelam; Song, Li; Liu, Zheng; Reddy, Arava Leela Mohana; Ci, Lijie; Vajtai, Robert; Zhang, Qing; Wei, Bingqing; Ajayan, Pulickel M

2011-07-31

Microscale supercapacitors provide an important complement to batteries in a variety of applications, including portable electronics. Although they can be manufactured using a number of printing and lithography techniques, continued improvements in cost, scalability and form factor are required to realize their full potential. Here, we demonstrate the scalable fabrication of a new type of all-carbon, monolithic supercapacitor by laser reduction and patterning of graphite oxide films. We pattern both in-plane and conventional electrodes consisting of reduced graphite oxide with micrometre resolution, between which graphite oxide serves as a solid electrolyte. The substantial amounts of trapped water in the graphite oxide makes it simultaneously a good ionic conductor and an electrical insulator, allowing it to serve as both an electrolyte and an electrode separator with ion transport characteristics similar to that observed for Nafion membranes. The resulting micro-supercapacitor devices show good cyclic stability, and energy storage capacities comparable to existing thin-film supercapacitors.

Direct laser writing of micro-supercapacitors on hydrated graphite oxide films

NASA Astrophysics Data System (ADS)

Gao, Wei; Singh, Neelam; Song, Li; Liu, Zheng; Reddy, Arava Leela Mohana; Ci, Lijie; Vajtai, Robert; Zhang, Qing; Wei, Bingqing; Ajayan, Pulickel M.

2011-08-01

Microscale supercapacitors provide an important complement to batteries in a variety of applications, including portable electronics. Although they can be manufactured using a number of printing and lithography techniques, continued improvements in cost, scalability and form factor are required to realize their full potential. Here, we demonstrate the scalable fabrication of a new type of all-carbon, monolithic supercapacitor by laser reduction and patterning of graphite oxide films. We pattern both in-plane and conventional electrodes consisting of reduced graphite oxide with micrometre resolution, between which graphite oxide serves as a solid electrolyte. The substantial amounts of trapped water in the graphite oxide makes it simultaneously a good ionic conductor and an electrical insulator, allowing it to serve as both an electrolyte and an electrode separator with ion transport characteristics similar to that observed for Nafion membranes. The resulting micro-supercapacitor devices show good cyclic stability, and energy storage capacities comparable to existing thin-film supercapacitors.

Dynamics in the Plastic Crystalline Phases of Cyclohexanol and Cyclooctanol Studied by Quasielastic Neutron Scattering.

PubMed

Novak, E; Jalarvo, N; Gupta, S; Hong, K; Förster, S; Egami, T; Ohl, M

2018-06-01

Plastic crystals are a promising candidate for solid state ionic conductors. In this work, quasielastic neutron scattering is employed to investigate the center of mass diffusive motions in two types of plastic crystalline cyclic alcohols: cyclohexanol and cyclooctanol. Two separate motions are observed which are attributed to long-range translational diffusion (α-process) and cage rattling (fast β-process). Residence times and diffusion coefficients are calculated for both processes, along with the confinement distances for the cage rattling. In addition, a binary mixture of these two materials is measured to understand how the dynamics change when a second type of molecule is added to the matrix. It is observed that, upon the addition of the larger cyclooctanol molecules into the cyclohexanol solution, the cage size decreases, which causes a decrease in the observed diffusion rates for both the α- and fast β-processes.

Alkali oxide-tantalum oxide and alkali oxide-niobium oxide ionic conductors

NASA Technical Reports Server (NTRS)

Roth, R. S.; Parker, H. S.; Brower, W. S.; Minor, D.

1974-01-01

A search was made for new cationic conducting phases in alkali-tantalate and niobate systems. The phase equilibrium diagrams were constructed for the six binary systems Nb2O5-LiNbO3, Nb2O5-NaNbO3, Nb2O5-KNbO3, Ta2O5-NaTaO3, Ta2O5-LiTaO3, and Ta2O5-KTaO3. Various other binary and ternary systems were also examined. Pellets of nineteen phases were evaluated (by the sponsoring agency) by dielectric loss measurements. Attempts were made to grow large crystals of eight different phases. The system Ta2O5-KTaO3 contains at least three phases which showed peaks in dielectric loss vs. temperature. All three contain structures related to the tungsten bronzes with alkali ions in non-stoichiometric crystallographic positions.

Electro-catalytic oxidation device for removing carbon from a fuel reformate

DOEpatents

Liu, Di-Jia [Naperville, IL

2010-02-23

An electro-catalytic oxidation device (ECOD) for the removal of contaminates, preferably carbonaceous materials, from an influent comprising an ECOD anode, an ECOD cathode, and an ECOD electrolyte. The ECOD anode is at a temperature whereby the contaminate collects on the surface of the ECOD anode as a buildup. The ECOD anode is electrically connected to the ECOD cathode, which consumes the buildup producing electricity and carbon dioxide. The ECOD anode is porous and chemically active to the electro-catalytic oxidation of the contaminate. The ECOD cathode is exposed to oxygen, and made of a material which promotes the electro-chemical reduction of oxygen to oxidized ions. The ECOD electrolyte is non-permeable to gas, electrically insulating and a conductor to oxidized. The ECOD anode is connected to the fuel reformer and the fuel cell. The ECOD electrolyte is between and in ionic contact with the ECOD anode and the ECOD cathode.

All-solid electrodes with mixed conductor matrix

DOEpatents

Huggins, Robert A.; Boukamp, Bernard A.

1984-01-01

Alkali metal based electrochemical cells offer a great deal of promise for applications in many areas such as electric vehicles and load leveling purposes in stationary power plants. Lithium is an attractive candidate as the electroactive species in such cells since lithium is very electropositive, abundant and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and normally is operated at elevated temperatures. The subject invention provides an electrochemical cell in one embodiment of which lithium is the electroactive species. The cell comprises an electrolyte, a positive electrode, and a negative electrode, either or both of which is an all-solid, composite microstructural electrode containing both a reactant phase and a mixed ionic-electronic conducting phase. The cells of the subject invention exhibit improved kinetic features, current and power densities. Repeated charging and discharging of these cells can be accomplished without appreciable loss of capacity.

Biology's built-in Faraday cages

NASA Astrophysics Data System (ADS)

Klee, Maurice M.

2014-05-01

Biological fluids are water-based, ionic conductors. As such, they have both high relative dielectric constants and substantial conductivities, meaning they are lossy dielectrics. These fluids contain charged molecules (free charges), whose movements play roles in essentially all cellular processes from metabolism to communication with other cells. Using the problem of a point source in air above a biological fluid of semi-infinite extent, the bound charges in the fluid are shown to perform the function of a fast-acting Faraday cage, which protects the interior of the fluid from external electric fields. Free charges replace bound charges in accordance with the fluid's relaxation time, thereby providing a smooth transition between the initial protection provided by the bound charges and the steady state protection provided by the free charges. The electric fields within the biological fluid are thus small for all times just as they would be inside a classical Faraday cage.

Triple-conducting layered perovskites as cathode materials for proton-conducting solid oxide fuel cells.

PubMed

Kim, Junyoung; Sengodan, Sivaprakash; Kwon, Goeun; Ding, Dong; Shin, Jeeyoung; Liu, Meilin; Kim, Guntae

2014-10-01

We report on an excellent anode-supported H(+) -SOFC material system using a triple conducting (H(+) /O(2-) /e(-) ) oxide (TCO) as a cathode material for H(+) -SOFCs. Generally, mixed ionic (O(2-) ) and electronic conductors (MIECs) have been selected as the cathode material of H(+) -SOFCs. In an H(+) -SOFC system, however, MIEC cathodes limit the electrochemically active sites to the interface between the proton conducting electrolyte and the cathode. New approaches to the tailoring of cathode materials for H(+) -SOFCs should therefore be considered. TCOs can effectively extend the electrochemically active sites from the interface between the cathode and the electrolyte to the entire surface of the cathode. The electrochemical performance of NBSCF/BZCYYb/BZCYYb-NiO shows excellent long term stability for 500 h at 1023 K with high power density of 1.61 W cm(-2) . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of ceramic products and processing techniques in space. [using computerized simulation

NASA Technical Reports Server (NTRS)

Markworth, A. J.; Oldfield, W.

1974-01-01

An analysis of the solidification kinetics of beta alumina in a zero-gravity environment was carried out, using computer-simulation techniques, in order to assess the feasibility of producing high-quality single crystals of this material in space. The two coupled transport processes included were movement of the solid-liquid interface and diffusion of sodium atoms in the melt. Results of the simulation indicate that appreciable crystal-growth rates can be attained in space. Considerations were also made of the advantages offered by high-quality single crystals of beta alumina for use as a solid electrolyte; these clearly indicate that space-grown materials are superior in many respects to analogous terrestrially-grown crystals. Likewise, economic considerations, based on the rapidly expanding technological applications for beta alumina and related fast ionic conductors, reveal that the many superior qualities of space-grown material justify the added expense and experimental detail associated with space processing.

Simulation of local ion transport in lamellar block copolymer electrolytes based on electron micrographs

DOE PAGES

Chintapalli, Mahati; Higa, Kenneth; Chen, X. Chelsea; ...

2016-12-19

A method is presented in this paper to relate local morphology and ionic conductivity in a solid, lamellar block copolymer electrolyte for lithium batteries, by simulating conductivity through transmission electron micrographs. The electrolyte consists of polystyrene-block-poly(ethylene oxide) mixed with lithium bis(trifluoromethanesulfonyl) imide salt (SEO/LiTFSI), where the polystyrene phase is structural phase and the poly(ethylene oxide)/LiTFSI phase is ionically conductive. The electric potential distribution is simulated in binarized micrographs by solving the Laplace equation with constant potential boundary conditions. A morphology factor, f, is reported for each image by calculating the effective conductivity relative to a homogenous conductor. Images from twomore » samples are examined, one annealed with large lamellar grains and one unannealed with small grains. The average value off is 0.45 ± 0.04 for the annealed sample, and 0.37 ± 0.03 for the unannealed sample, both close to the value predicted by effective medium theory, 1/2. Simulated conductivities are compared to published experimental conductivities. The value of f Unannealed/f Annealed is 0.82 for simulations and 6.2 for experiments. Simulation results correspond well to predictions by effective medium theory but do not explain the experimental measurements. Finally, observation of nanoscale morphology over length scales greater than the size of the micrographs (~1 μm) may be required to explain the experimental results.« less

Combined modification by LiAl11O17 and NaAl11O17 to enhance the electrochemical performance of Li4Ti5O12

NASA Astrophysics Data System (ADS)

Zhang, Bo; Han, Jian-Ping; Wang, Li-Ying; Lun, Ning; Zhu, Hui-Ling; Yin, Long-Wei; Li, Hui; Qi, Yong-Xin; Bai, Yu-Jun

2018-07-01

The intrinsically moderate Li-ion diffusion coefficient and poor electronic conductivity of Li4Ti5O12 (LTO) restricts the practical application in Li-ion batteries. In view of the rapid two-dimensional diffusion channels in ionic conductor of LiNaAl22O34 for Li-ions, the LTO modified by combining equivalent molar ratio of LiAl11O17 with NaAl11O17 (LNAO) was fabricated by a simple reaction between LiNO3, Na2CO3, Al(NO3)3ṡ9H2O and LTO at various sintering temperatures. The product with a LNAO/LTO mass ratio of 0.0106 and calcined at 600 °C achieved reversible capacities of 163.8, 160.6, 156.5, 150.9, 132.9 and 163.4 mAh g-1 at the current rates of 100, 200, 400, 800, 1600 and 100 mA g-1, respectively. Even cycled 800 times at 500 mA g-1, a capacity of 147.9 mAh g-1 was retained. The outstanding cycling and rate performance is attributable to the simultaneously formed LNAO coating on the LTO particles and superficial Al3+ doping in the LTO, achieving combined improvement in the ionic and electronic conductivities of LTO and thus boosting the comprehensive electrochemical performance of LTO.

Simulation of local ion transport in lamellar block copolymer electrolytes based on electron micrographs

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

Chintapalli, Mahati; Higa, Kenneth; Chen, X. Chelsea

A method is presented in this paper to relate local morphology and ionic conductivity in a solid, lamellar block copolymer electrolyte for lithium batteries, by simulating conductivity through transmission electron micrographs. The electrolyte consists of polystyrene-block-poly(ethylene oxide) mixed with lithium bis(trifluoromethanesulfonyl) imide salt (SEO/LiTFSI), where the polystyrene phase is structural phase and the poly(ethylene oxide)/LiTFSI phase is ionically conductive. The electric potential distribution is simulated in binarized micrographs by solving the Laplace equation with constant potential boundary conditions. A morphology factor, f, is reported for each image by calculating the effective conductivity relative to a homogenous conductor. Images from twomore » samples are examined, one annealed with large lamellar grains and one unannealed with small grains. The average value off is 0.45 ± 0.04 for the annealed sample, and 0.37 ± 0.03 for the unannealed sample, both close to the value predicted by effective medium theory, 1/2. Simulated conductivities are compared to published experimental conductivities. The value of f Unannealed/f Annealed is 0.82 for simulations and 6.2 for experiments. Simulation results correspond well to predictions by effective medium theory but do not explain the experimental measurements. Finally, observation of nanoscale morphology over length scales greater than the size of the micrographs (~1 μm) may be required to explain the experimental results.« less

Ionic protein-lipid interaction at the plasma membrane: what can the charge do?

PubMed

Li, Lunyi; Shi, Xiaoshan; Guo, Xingdong; Li, Hua; Xu, Chenqi

2014-03-01

Phospholipids are the major components of cell membranes, but they have functional roles beyond forming lipid bilayers. In particular, acidic phospholipids form microdomains in the plasma membrane and can ionically interact with proteins via polybasic sequences, which can have functional consequences for the protein. The list of proteins regulated by ionic protein-lipid interaction has been quickly expanding, and now includes membrane proteins, cytoplasmic soluble proteins, and viral proteins. Here we review how acidic phospholipids in the plasma membrane regulate protein structure and function via ionic interactions, and how Ca(2+) regulates ionic protein-lipid interactions via direct and indirect mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

46 CFR 111.05-31 - Grounding conductors for systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Grounding conductors for systems. 111.05-31 Section 111... Grounding conductors for systems. (a) A conductor for grounding a direct-current system must be the larger of: (1) The largest conductor supplying the system; or (2) No. 8 AWG (8.4mm2). (b) A conductor for...

46 CFR 111.05-31 - Grounding conductors for systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Grounding conductors for systems. 111.05-31 Section 111... Grounding conductors for systems. (a) A conductor for grounding a direct-current system must be the larger of: (1) The largest conductor supplying the system; or (2) No. 8 AWG (8.4mm2). (b) A conductor for...

Semi-flexible gas-insulated transmission line using electric field stress shields

DOEpatents

Cookson, A.H.; Dale, S.J.; Bolin, P.C.

1982-12-28

A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements and the stress shields may also be utilized in connection with a plug and socket arrangement for providing electrical connection between main conductor sections. 10 figs.

Microscopic characterization of tension wood cell walls of Japanese beech (Fagus crenata) treated with ionic liquids.

PubMed

Kanbayashi, Toru; Miyafuji, Hisashi

2016-09-01

Tension wood that is an abnormal part formed in angiosperms has been barely used for wood industry. In this study, to utilize the tension wood effectively by means of liquefaction using ionic liquid, we performed morphological and topochemical determination of the changes in tension wood of Japanese beech (Fagus crenata) during ionic liquid treatment at the cellular level using light microscopy, scanning electron microscopy and confocal Raman microscopy. Ionic liquid treatment induced cell wall swelling in tension wood. Changes in the tissue morphology treated with ionic liquids were different between normal wood and tension wood, moreover the types of ionic liquids. The ionic liquid 1-ethyl-3-methylimidazolium chloride liquefied gelatinous layers rapidly, whereas 1-ethylpyridinium bromide liquefied slowly but delignified selectively. These novel insights into the deconstruction behavior of tension wood cell walls during ionic liquid treatment provide better understanding of the liquefaction mechanism. The obtained knowledge will contribute to development of an effective chemical processing of tension wood using ionic liquids and lead to efficient use of wood resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Induction heaters used to heat subsurface formations

DOEpatents

Nguyen, Scott Vinh [Houston, TX; Bass, Ronald M [Houston, TX

2012-04-24

A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300.degree. C.

Multi-Scale Simulation of High Energy Density Ionic Liquids

DTIC Science & Technology

2007-06-19

and simulation of ionic liquids (ILs). A polarizable model was developed to simulate ILs more accurately at the atomistic level. A multiscale coarse...propellant, 1- hydroxyethyl-4-amino-1, 2, 4-triazolium nitrate (HEATN), were studied with the all-atom polarizable model. The mechanism suggested for HEATN...with this AFOSR-supported project, a polarizable forcefield for the ionic liquids such as 1-ethyl-3-methylimidazolium nitrate (EMIM*/NO3-) was

Method for making conductors for ferrite memory arrays. [from pre-formed metal conductors

NASA Technical Reports Server (NTRS)

Heckler, C. H.; Baba, P. D.; Bhiwandker, N. C. (Inventor)

1974-01-01

The ferrite memory arrays are made from pre-formed metal conductors for the ferrite arrays. The conductors are made by forming a thin sheet of a metallizing paste of metal alloy powder, drying the paste layer, bisque firing the dried sheet at a first temperature, and then punching the conductors from the fired sheet. During the bisque firing, the conductor sheet shrinks to 58 percent of its pre-fired volume and the alloy particles sinter together. The conductors are embedded in ferrite sheet material and finally fired at a second higher temperature during which firing the conductors shrink approximately the same degree as the ferrite material.

Mixed ionic and electronic conducting ceramic membranes for hydrocarbon processing

DOEpatents

Van Calcar, Pamela; Mackay, Richard; Sammells, Anthony F.

2002-01-01

The invention relates to mixed phase materials for the preparation of catalytic membranes which exhibit ionic and electronic conduction and which exhibit improved mechanical strength compared to single phase ionic and electronic conducting materials. The mixed phase materials are useful for forming gas impermeable membranes either as dense ceramic membranes or as dense thin films coated onto porous substrates. The membranes and materials of this invention are useful in catalytic membrane reactors in a variety of applications including synthesis gas production. One or more crystalline second phases are present in the mixed phase material at a level sufficient to enhance the mechanical strength of the mixture to provide membranes for practical application in CMRs.

Applications of Synthetic Microchannel and Nanopore Systems

NASA Astrophysics Data System (ADS)

Hinkle, Thomas Preston

This thesis describes research conducted on the physics and applications of micro- and nanoscale ion-conducting channels. Making use of the nanoscale physics that takes place in the vicinity of charged surfaces, there is the possibility that nanopores, holes on the order of 1 nm in size, could be used to make complex integrated ionic circuits. For inspiration on what such circuits could achieve we only need to look to biology systems, immensely complex machines that at their most basic level require precise control of ions and intercellular electric potentials to function. In order to contribute to the ever expanding field of nanopore research, we engineered novel hybrid insulator-conductor nanopores that behave analagously to ionic diodes, which allow passage of current flow in one direction but severely limit the current in the opposite direction. The experiments revealed that surface polarization of the conducting material can induce the formation of an electrical double layer in the same way static surface charges can. Furthermore, we showed that the hybrid device behaved similar to an ionic diode, and could see potential use as a standard rectifying element in ionic circuits. Another application based on ion conducting channels is resistive pulse sensing, a single particle detection and characterization method. We present three main experiments that expand the capacity of resistive pulse sensing for particle characterization. First, we demonstrate how resistive pulse sensing in pores with longitudinal irregularities can be used to measure the lengths of individual nanoparticles. Then, we describe an entirely new hybrid approach to resistive pulse sensing, whereby the electrical measurements are combined with simultaneous optical imaging. The hybrid method allows for validation of the resistive pulse signals and will greatly contribute to their interpretability. We present experiments that explore some of the possibilities of the hybrid method. Then, building off the hybrid method we present experiments performed to measure single particle deformability with resistive pulse sensing. Using a novel microfluidic channel design, we were able to reproducibily induce bidirectional deformation of cells. We describe how these deformations could be detected with the resistive pulse signal alone, paving the way for resistive pulse sensing based cell deformability cytometers.

Ionic liquid based multifunctional double network gel

NASA Astrophysics Data System (ADS)

Ahmed, Kumkum; Higashihara, Tomoya; Arafune, Hiroyuki; Kamijo, Toshio; Morinaga, Takashi; Sato, Takaya; Furukawa, Hidemitsu

2015-04-01

Gels are a promising class of soft and wet materials with diverse application in tissue engineering and bio-medical purpose. In order to accelerate the development of gels, it is required to synthesize multi-functional gels of high mechanical strength, ultra low surface friction and suitable elastic modulus with a variety of methods and new materials. Among many types of gel ionic gel made from ionic liquids (ILs) could be used for diverse applications in electrochemical devices and in the field of tribology. IL, a promising materials for lubrication, is a salt with a melting point lower than 100 °C. As a lubricant, ILs are characterized by an extremely low vapor pressure, high thermal stability and high ion conductivity. In this work a novel approach of making double network DN ionic gel using IL has been made utilizing photo polymerization process. A hydrophobic monomer Methyl methacrylate (MMA) has been used as a first network and a hydrophobic IL monomer, N,N-diethyl-N-(2-mthacryloylethyl)-N-methylammonium bistrifluoromethylsulfonyl)imide (DEMM-TFSI) has been used as a second network using photo initiator benzophenon and crosslinker triethylene glycol dimethacrylate (TEGDMA). The resulting DN ionic gel shows transparency, flexibility, high thermal stability, good mechanical toughness and low friction coefficient value which can be a potential candidate as a gel slider in different mechanical devices and can open a new area in the field of gel tribology.

Glass for Solid State Devices

NASA Technical Reports Server (NTRS)

Bailey, R. F.

1982-01-01

Glass film has low intrinsic compressive stress for isolating active layers of magnetic-bubble and other solid-state devices. Solid-state device structure incorporates low-stress glasses as barrier and spacer layers. Glass layers mechanically isolate substrate, conductor, and nickel/iron layers.

Testing of the 3M Company Composite Conductor

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

Stovall, John P; Rizy, D Tom; Kisner, Roger A

2010-10-01

The 3M Company has developed a high-temperature low-sag conductor referred to as Aluminum-Conductor Composite-Reinforced or ACCR. The conductor uses an aluminum metal matrix material to replace the steel in conventional conductors. The objective of this work is to accelerate the commercial acceptance by electric utilities of this new conductor design by testing four representative conductor classes in controlled conditions. A unique facility called the Powerline Conductor Accelerated Testing (PCAT) Facility was built at ORNL for testing overhead conductors. The PCAT has been uniquely designed for testing overhead bare transmission line conductors at high currents and temperatures after they have beenmore » installed and tensioned to the manufacturer's specifications. The ability to operate a transmission line conductor in this manner does not exist elsewhere in the United States. Four classes of ACCR cable designed by the 3M Company have been successfully test at ORNL small, medium, large and small/compact. Based on these and other manufacturer tests, the 3M Company has successfully introduced the ACCR into the commercial market and has completed over twenty installations for utility companies.« less

30 CFR Appendix I to Subpart D of... - Appendix I to Subpart D of Part 18

Code of Federal Regulations, 2011 CFR

2011-07-01

... diameter of three-conductor portable power cables with tolerances in inches—601 to 5,000 volts. 8 Fuse... diameters. Table 1—Portable Power Cable Ampacities—600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature—40 °C. Ambient) Conductor size—AWG or MCM Single conductor 2-conductor, round or flat 3-conductor...

30 CFR Appendix I to Subpart D of... - Appendix I to Subpart D of Part 18

Code of Federal Regulations, 2010 CFR

2010-07-01

... diameter of three-conductor portable power cables with tolerances in inches—601 to 5,000 volts. 8 Fuse... diameters. Table 1—Portable Power Cable Ampacities—600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature—40 °C. Ambient) Conductor size—AWG or MCM Single conductor 2-conductor, round or flat 3-conductor...

"Null-E" magnetic bearings

NASA Astrophysics Data System (ADS)

Filatov, Alexei Vladimirovich

2002-09-01

Using electromagnetic forces to suspend rotating objects (rotors) without mechanical contact is often an appealing technical solution. Magnetic suspensions are typically required to have adequate load capacity and stiffness, and low rotational loss. Other desired features include low price, high reliability and manufacturability. With recent advances in permanent-magnet materials, the required forces can often be obtained by simply using the interaction between permanent magnets. While a magnetic bearing based entirely on permanent magnets could be expected to be inexpensive, reliable and easy to manufacture, a fundamental physical principle known as Earnshaw's theorem maintains that this type of suspension cannot be statically stable. Therefore, some other physical mechanisms must be included. One such mechanism employs the interaction between a conductor and a nonuniform magnetic field in relative motion. Its advantages include simplicity, reliability, wide range of operating temperature and system autonomy (no external wiring and power supplies are required). The disadvantages of the earlier embodiments were high rotational loss, low stiffness and load capacity. This dissertation proposes a novel type of magnetic bearing stabilized by the field-conductor interaction. One of the advantages of this bearing is that no electric field, E, develops in the conductor during the rotor rotation when the system is in no-load equilibrium. Because of this we refer to it as the Null-E Bearing. Null-E Bearings have potential for lower rotational loss and higher load capacity and stiffness than other bearings utilizing the field-conductor interaction. Their performance is highly insensitive to manufacturing inaccuracies. The Null-E Bearing in its basic form can be augmented with supplementary electronics to improve its performance. Depending on the degree of the electronics involvement, a variety of magnetic bearings can be developed ranging from a completely passive to an active magnetic bearing of a novel type. This dissertation contains theoretical analysis of the Null-E Bearing operation, including derivation of the stability conditions and estimation of some of the rotational losses. The validity of the theoretical conclusions has been demonstrated by building and testing a prototype in which non-contact suspension of a 3.2-kg rotor is achieved at spin speeds above 18 Hz.

Enhancing oxygen transport through Mixed-Ionic-and-Electronic-Conducting ceramic membranes

NASA Astrophysics Data System (ADS)

Yu, Anthony S.

Ceramic membranes based on Mixed-Ionic-and-Electronic-Conducting (MIEC) oxides are capable of separating oxygen from air in the presence of an oxygen partial-pressure gradient. These MIEC membranes show great promise for oxygen consuming industrial processes, such as the production of syngas from steam reforming of natural gas (SRM), as well as for electricity generation in Solid Oxide Fuel Cells (SOFC). For both applications, the overall performance is dictated by the rate of oxygen transport across the membrane. Oxygen transport across MIEC membranes is composed of a bulk oxygen-ion diffusion process and surface processes, such as surface reactions and adsorption/desorption of gaseous reactants/products. The main goal of this thesis was to determine which process is rate-limiting in order to significantly enhance the overall rate of oxygen transport in MIEC membrane systems. The rate-limiting step was determined by evaluating the total resistance to oxygen transfer, Rtot. Rtot is the sum of a bulk diffusion resistance in the membrane itself, Rb, and interfacial loss components, Rs. Rb is a function of the membrane's ionic conductivity and thickness, while Rs arises primarily from slow surface-exchange kinetics that cause the P(O2) at the surfaces of the membrane to differ from the P(O 2) in the adjacent gas phases. Rtot can be calculated from the Nernst potential across the membrane and the measured oxygen flux. The rate-limiting process can be determined by evaluating the relative contributions of the various losses, Rs and Rb, to Rtot. Using this method, this thesis demonstrates that for most membrane systems, Rs is the dominating factor. In the development of membrane systems with high oxygen transport rates, thin membranes with high ionic conductivities are required to achieve fast bulk oxygen-ion diffusion. However, as membrane thickness is decreased, surface reaction kinetics become more important in determining the overall transport rate. The two approaches to increase surface reaction kinetics and decrease Rs that were examined in this thesis involved modifying the surface microstructure, as well as adding both metallic (e.g. Pt) and oxide (e.g. CeO2, La0.8Sr0.2FeO3) catalysts to both membrane surfaces. These two approaches were investigated for single-phase MIEC membrane reactors (La0.9Ca0.1FeO3-delta ), as well as composite membrane reactors composed of an electronic conductor (La0.8Sr-0.2CrO3-delta) and an ionic conductor (YSZ). The use of catalysts and microstructure modifications to decrease interfacial losses is equally important for SOFCs. In this thesis, the electrochemical activity and microstructure of metallic catalysts formed by "ex-solving" metals from an oxide lattice, and oxide catalysts deposited by Atomic Layer Deposition (ALD) were investigated. It is shown that these methods for depositing catalysts resulted in very different effects on electrode performance when compared to the same catalysts deposited by wet impregnation. For example, when transition metals, such as Ni and Co, were "ex-solved" from a La0.8Sr0.2CrO3-delta anode lattice, these "ex-solved" metal particles not only exhibited great catalytic activity, they were also less prone to coking compared to their wet impregnated counterparts. On the cathode side, thin layers of various oxides (e.g. Al 2O3, CeOx, SrO) that were deposited using ALD also exhibited drastically different electrochemical activity compared to their wet impregnated counterparts. It was determined that differences in electrochemical activity could be attributed to a difference in the oxide morphology, showing that a catalyst's microstructure and morphology are very important in dictating its overall activity in SOFC electrodes.

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: III. The importance of strand surface roughness in long twist pitch conductors

DOE PAGES

Sanabria, Charlie; Lee, Peter J.; Starch, William; ...

2016-05-31

As part of the ITER conductor qualification process, 3 m long Cable-in-Conduit Conductors (CICCs) were tested at the SULTAN facility under conditions simulating ITER operation so as to establish the current sharing temperature, T cs, as a function of multiple full Lorentz force loading cycles. After a comprehensive evaluation of both the Toroidal Field (TF) and the Central Solenoid (CS) conductors, it was found that T cs degradation was common in long twist pitch TF conductors while short twist pitch CS conductors showed some T cs increase. However, one kind of TF conductors containing superconducting strand fabricated by the Bochvarmore » Institute of Inorganic Materials (VNIINM) avoided T cs degradation despite having long twist pitch. In our earlier metallographic autopsies of long and short twist pitch CS conductors, we observed a substantially greater transverse strand movement under Lorentz force loading for long twist pitch conductors, while short twist pitch conductors had negligible transverse movement. With help from the literature, we concluded that the transverse movement was not the source of T cs degradation but rather an increase of the compressive strain in the Nb 3Sn filaments possibly induced by longitudinal movement of the wires. Like all TF conductors this TF VNIINM conductor showed large transverse motions under Lorentz force loading, but Tcs actually increased, as in all short twist pitch CS conductors. We here propose that the high surface roughness of the VNIINM strand may be responsible for the suppression of the compressive strain enhancement (characteristic of long twist pitch conductors). Furthermore, it appears that increasing strand surface roughness could improve the performance of long twist pitch CICCs.« less

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: III. The importance of strand surface roughness in long twist pitch conductors

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

Sanabria, Charlie; Lee, Peter J.; Starch, William

As part of the ITER conductor qualification process, 3 m long Cable-in-Conduit Conductors (CICCs) were tested at the SULTAN facility under conditions simulating ITER operation so as to establish the current sharing temperature, T cs, as a function of multiple full Lorentz force loading cycles. After a comprehensive evaluation of both the Toroidal Field (TF) and the Central Solenoid (CS) conductors, it was found that T cs degradation was common in long twist pitch TF conductors while short twist pitch CS conductors showed some T cs increase. However, one kind of TF conductors containing superconducting strand fabricated by the Bochvarmore » Institute of Inorganic Materials (VNIINM) avoided T cs degradation despite having long twist pitch. In our earlier metallographic autopsies of long and short twist pitch CS conductors, we observed a substantially greater transverse strand movement under Lorentz force loading for long twist pitch conductors, while short twist pitch conductors had negligible transverse movement. With help from the literature, we concluded that the transverse movement was not the source of T cs degradation but rather an increase of the compressive strain in the Nb 3Sn filaments possibly induced by longitudinal movement of the wires. Like all TF conductors this TF VNIINM conductor showed large transverse motions under Lorentz force loading, but Tcs actually increased, as in all short twist pitch CS conductors. We here propose that the high surface roughness of the VNIINM strand may be responsible for the suppression of the compressive strain enhancement (characteristic of long twist pitch conductors). Furthermore, it appears that increasing strand surface roughness could improve the performance of long twist pitch CICCs.« less

Design of a Wireless Sensor Module for Monitoring Conductor Galloping of Transmission Lines.

PubMed

Huang, Xinbo; Zhao, Long; Chen, Guimin

2016-10-09

Conductor galloping may cause flashovers and even tower collapses. The available conductor galloping monitoring methods often employ acceleration sensors to measure the conductor translations without considering the conductor twist. In this paper, a new sensor for monitoring conductor galloping of transmission lines based on an inertial measurement unit and wireless communication is proposed. An inertial measurement unit is used for collecting the accelerations and angular rates of a conductor, which are further transformed into the corresponding geographic coordinate frame using a quaternion transformation to reconstruct the galloping of the conductor. Both the hardware design and the software design are described in details. The corresponding test platforms are established, and the experiments show the feasibility and accuracy of the proposed monitoring sensor. The field operation of the proposed sensor in a conductor spanning 734 m also shows its effectiveness.

30 CFR 57.12011 - High-potential electrical conductors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-potential electrical conductors. 57.12011... Electricity Surface and Underground § 57.12011 High-potential electrical conductors. High-potential electrical conductors shall be covered, insulated, or placed to prevent contact with low potential conductors. ...

33 CFR 183.445 - Conductors: Protection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Conductors: Protection. 183.445 Section 183.445 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Conductors: Protection. (a) Each conductor or group of conductors that passes through a bulkhead, structural...