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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Battery structures, self-organizing structures and related methods

An energy storage device includes a first electrode comprising a first material and a second electrode comprising a second material, at least a portion of the first and second materials forming an interpenetrating network when dispersed in an electrolyte, the electrolyte, the first material and the second material are selected so that the first and second materials exert a repelling force on each other when combined. An electrochemical device, includes a first electrode in electrical communication with a first current collector; a second electrode in electrical communication with a second current collector; and an ionically conductive medium in ionic contact with said first and second electrodes, wherein at least a portion of the first and second electrodes form an interpenetrating network and wherein at least one of the first and second electrodes comprises an electrode structure providing two or more pathways to its current collector.

25 ENERGY STORAGE↗
DOE OSTI2012

Battery structures, self-organizing structures and related methods

An energy storage device includes a first electrode comprising a first material and a second electrode comprising a second material, at least a portion of the first and second materials forming an interpenetrating network when dispersed in an electrolyte, the electrolyte, the first material and the second material are selected so that the first and second materials exert a repelling force on each other when combined. An electrochemical device, includes a first electrode in electrical communication with a first current collector; a second electrode in electrical communication with a second current collector; and an ionically conductive medium in ionic contact with said first and second electrodes, wherein at least a portion of the first and second electrodes form an interpenetrating network and wherein at least one of the first and second electrodes comprises an electrode structure providing two or more pathways to its current collector.

25 ENERGY STORAGE↗
DOE OSTI2012

Battery structures, self-organizing structures and related methods

An energy storage device includes a first electrode comprising a first material and a second electrode comprising a second material, at least a portion of the first and second materials forming an interpenetrating network when dispersed in an electrolyte, the electrolyte, the first material and the second material are selected so that the first and second materials exert a repelling force on each other when combined. An electrochemical device, includes a first electrode in electrical communication with a first current collector; a second electrode in electrical communication with a second current collector; and an ionically conductive medium in ionic contact with said first and second electrodes, wherein at least a portion of the first and second electrodes form an interpenetrating network and wherein at least one of the first and second electrodes comprises an electrode structure providing two or more pathways to its current collector.

25 ENERGY STORAGE↗
DOE OSTI2012

Battery structures, self-organizing structures and related methods

An energy storage device includes a first electrode comprising a first material and a second electrode comprising a second material, at least a portion of the first and second materials forming an interpenetrating network when dispersed in an electrolyte, the electrolyte, the first material and the second material are selected so that the first and second materials exert a repelling force on each other when combined. An electrochemical device, includes a first electrode in electrical communication with a first current collector; a second electrode in electrical communication with a second current collector; and an ionically conductive medium in ionic contact with said first and second electrodes, wherein at least a portion of the first and second electrodes form an interpenetrating network and wherein at least one of the first and second electrodes comprises an electrode structure providing two or more pathways to its current collector.

25 ENERGY STORAGE↗
DOE OSTI2013

Battery Structures, self-organizing structures, and related methods

An energy storage device includes a first electrode comprising a first material and a second electrode comprising a second material, at least a portion of the first and second materials forming an interpenetrating network when dispersed in an electrolyte, the electrolyte, the first material and the second material are selected so that the first and second materials exert a repelling force on each other when combined. An electrochemical device, includes a first electrode in electrical communication with a first current collector; a second electrode in electrical communication with a second current collector; and an ionically conductive medium in ionic contact with said first and second electrodes, wherein at least a portion of the first and second electrodes form an interpenetrating network and wherein at least one of the first and second electrodes comprises an electrode structure providing two or more pathways to its current collector.

25 ENERGY STORAGE↗
DOE OSTI2019

Investigation of the Piezoelectric Resonance in Stoichiometric LiNbO{sub 3} Crystals at High Temperatures and Conductivities

The piezoelectric characteristics, dielectric properties, and ionic conductivity of close-to-stoichiometry LiNbO{sub 3{sub s{sub t{sub o{sub i{sub c{sub h}}}}}}} crystals have been investigated in a wide temperature range (300–850 K) with the aim of establishing the conditions of use of lithium-niobate-based piezoelectric resonators at high temperatures and, accordingly, high conductivities. It is shown that the piezoelectric phenomenon in LiNbO{sub 3{sub s{sub t{sub o{sub i{sub c{sub h}}}}}}} crystals is observed in a certain temperature range ΔT (and, correspondingly, at certain static-conductivity relaxation times Δτ{sub V}) and a frequency range Δω{sub R} at the condition τ{sub V}{sup −1}≪ ω{sub R} satisfied. Apparently, not only LiNbO{sub 3{sub s{sub t{sub o{sub i{sub c{sub h}}}}}}} crystals exhibit such regularities, but also some other piezoelectric materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS2003

Mixed Conducting Electrodes for Better AMTEC Cells

Electrode materials that exhibit mixed conductivity (that is, both electronic and ionic conductivity) have been investigated in a continuing effort to improve the performance of the alkali metal thermal-to-electric converter (AMTEC). These electrode materials are intended primarily for use on the cathode side of the sodium-ion-conducting solid electrolyte of a sodium-based AMTEC cell. They may also prove useful in sodium-sulfur batteries, which are under study for use in electric vehicles. An understanding of the roles played by the two types of conduction in the cathode of a sodium-based AMTEC cell is prerequisite to understanding the advantages afforded by these materials. In a sodium-based AMTEC cell, the anode face of an anode/solid-electrolyte/cathode sandwich is exposed to Na vapor at a suitable pressure. Upon making contact with the solid electrolyte on the anode side, Na atoms oxidize to form Na+ ions and electrons. Na+ ions then travel through the electrolyte to the cathode. Na+ ions leave the electrolyte at the cathode/electrolyte interface and are reduced by electrons that have been conducted through an external electrical load from the anode to the cathode. Once the Na+ ions have been reduced to Na atoms, they travel through the cathode to vaporize into a volume where the Na vapor pressure is much lower than it is on the anode side. Thus, the cathode design is subject to competing requirements to be thin enough to allow transport of sodium to the low-pressure side, yet thick enough to afford adequate electronic conductivity. The concept underlying the development of the present mixed conducting electrode materials is the following: The constraint on the thickness of the cathode can be eased by incorporating Na+ -ionconducting material to facilitate transport of sodium through the cathode in ionic form. At the same time, by virtue of the electronically conducting material mixed with the ionically conducting material, reduction of Na+ ions to Na atoms can take place throughout the thickness of the cathode. The net effect is to reduce the diffusion and flow resistance to sodium through the electrode while reducing the electronic resistance by providing shorter conduction paths for electrons. Reduced resistance to both sodium transport and electronic conductivity results in an increase in electric power output.

Ryan, Margaret↗
DOE OSTI2015

Liquid methanol under a static electric field

We report on an ab initio molecular dynamics study of liquid methanol under the effect of a static electric field. We found that the hydrogen-bond structure of methanol is more robust and persistent for field intensities below the molecular dissociation threshold whose value (≈0.31 V/Å) turns out to be moderately larger than the corresponding estimate obtained for liquid water. A sustained ionic current, with ohmic current-voltage behavior, flows in this material for field intensities above 0.36 V/Å, as is also the case of water, but the resulting ionic conductivity (≈0.40 S cm{sup −1}) is at least one order of magnitude lower than that of water, a circumstance that evidences a lower efficiency of proton transfer processes. We surmise that this study may be relevant for the understanding of the properties and functioning of technological materials which exploit ionic conduction, such as direct-methanol fuel cells and Nafion membranes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Tailoring Interface Structure in Highly Strained YSZ/STO Heterostructures

Heterostructures combining transition metal oxides, as compared to other materials, are able to accommodate very large amounts of epitaxial strain without breaking into islands or structural domains. Coherently strained interfaces are an interesting playground for the search of materials with enhanced ion diffusivities, of interest in devices for energy generation and storage. In this work we highlight the importance of the interface structure of highly strained YSZ/STO superlattices in determining an enhancement of their ionic conductivity. We show the role of growth orientation in controlling the structure and morphology of the interface. Results of density functional theory calculations are discussed, showing that the incompatibility of the oxygen positions at the interface planes plays a key role in stabilizing the high values of ionic conductivities.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Sodium superionic conduction in tetragonal Na{sub 3}PS{sub 4}

Highlights: • Na{sub 3}PS{sub 4} base solid electrolytes were fabricated by various synthetic routes. • The formation of phases in Na{sub 3+5x}P{sub 1–x}S{sub 4} depends on reaction conditions. • Tetragonal phase III showed the highest conductivity of 3.39 × 10{sup -3} S cm{sup -1}at 25 °C. • Structural analysis revealed the 3D conduction pathway in the tetragonal phase III. • Na{sub 3}PS{sub 4} functions as a solid electrolyte in all-solid-state sodium batteries. - Abstract: Sodium superionic conductors are highly promising as solid electrolytes for all-solid-state sodium batteries, with the capacity to improve energy and power density of liquid-electrolyte-based batteries and to address their safety issues. However, the ionic conductivity of sodium electrolytes remains roughly one order of magnitude lower than that of lithium systems. Herein, we report a synthesis method for a sodium superionic conductor, tetragonal Na{sub 3}PS{sub 4}, with an ionic conductivity of 3.39 × 10{sup −3} Scm{sup −1} at 25 °C—the highest value yet reported among sulfide-type sodium conductors. The high conductivity is achieved through quenching from 700 °C, which introduces sodium vacancies, and annealing at 450 °C, which increases vacancies and expands lattice volume. The phase is comprised of a framework of isolated PS{sub 4} tetrahedra, with partial distribution of Na over 3D pathways. The high intrinsic conductivity together with low grain boundary contribution and soft mechanical properties make Na{sub 3}PS{sub 4} a promising candidate for sodium solid electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Sliceable, Moldable, and Highly Conductive Electrolytes for All-Solid-State Batteries

All-solid-state batteries (ASSBs) require solid electrolytes with high ionic conductivity, stability, and deformability for optimal energy and power density. Here, we developed lithium-deficient lithium yttrium bromide (LYB) solid electrolytes, Li 3–x YBr 6–x (0 ≤ x ≤ 0.50), using a comelting method with controlled lithium deficiency. These electrolytes exhibit favorable mechanical properties such as high moldability and sliceability. The Li 2.65 YBr 5.65 composition has an ionic conductivity of 4.49 mS cm –1 at 25 °C and an activation energy of 0.28 eV. Compared to Li 3 YBr 6 , Li 2.65 YBr 5.65 demonstrates improved rate performance and cycling stability in ASSBs. High-resolution X-ray diffraction confirms the formation of the LYB phase with a C2/m space group. Structural analysis reveals increased cation disorder and larger polyhedral volumes for x > 0 in Li 3–x YBr 6–x , contributing to reduced Li + migration energy barriers. Bond valence site energy calculations and molecular dynamics simulations reveal enhanced 3D lithium-ion transport. NMR spectroscopy further highlights increased Li + dynamics and impurity elimination.

Poudel, Tej P. [Florida State Univ., Tallahassee, ↗
DOE OSTI2017

Order–Disorder Transitions and Superionic Conductivity in the Sodium nido -Undeca(carba)borates

The salt compounds NaB 11 H 14 , Na-7-CB10H13, Li-7-CB 10 H 13 , Na-7,8-C 2 B 9 H 12 , and Na-7,9-C 2 B 9 H 12 all contain geometrically similar, monocharged, nido-undeca(carba)borate anions (i.e., truncated icosohedral-shaped clusters constructed of only 11 instead of 12 {B-H} + {C-H} vertices and an additional number of compensating bridging and/or terminal H atoms). We used first-principles calculations, X-ray powder diffraction, differential scanning calorimetry, neutron vibrational spectroscopy, neutron elastic-scattering fixed-window scans, quasielastic neutron scattering, and electrochemical impedance measurements to investigate their structures, bonding potentials, phase-transition behaviors, anion orientational mobilities, and ionic conductivities compared to those of their closo-poly(carba)borate cousins. All exhibited order-disorder phase transitions somewhere between room temperature and 375 K. All disordered phases appear to possess highly reorientationally mobile anions (> ~10 10 jumps s -1 above 300 K) and cation-vacancy-rich, close-packed or body-center-cubic-packed structures [like previously investigated closo-poly(carba)borates]. Moreover, all disordered phases display superionic conductivities but with generally somewhat lower values compared to those for the related sodium and lithium salts with similar monocharged 1-CB 9 H 10 - and CB 11 H 12 - closo-carbaborate anions. This study significantly expands the known toolkit of solid-state, poly(carba)borate-based salts capable of superionic conductivities and provides valuable insights into the effect of crystal lattice, unit cell volume, number of carbon atoms incorporated into the anion, and charge polarization on ionic conductivity.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Synthesis, characterization, electrical and dielectric studies of AgCuI and Co-SnO{sub 2} composite solid electrolytes

Highlights: • The SCI–CDS composites were characterized by XRD, Far IR and SEM. • Conductivity reached 1.29 × 10{sup −4} S/cm at room temperature for x = 0.4 composition. • The value of dielectric constant decreases with the increase of frequency. - Abstract: The composite solid electrolytes of AgCuI (SCI) and Co-SnO{sub 2} (CDS) were prepared by direct mixing method. The phase structure, composition and surface morphology of the composites were explained by X-ray diffraction (XRD), Far infrared spectroscopy (Far IR) and Scanning electron microscopy (SEM). AC impedance spectroscopy revealed that the ionic conductivity was effectively increased with the increase of temperature. Presence of a semicircle in the impedance spectra shows the greater contribution of grain than the grain boundary. Addition of CDS particles enhanced the ionic conductivity of the composites, reached a maximum value σ = 1.29 × 10{sup −4} S cm{sup −1} at room temperature for x = 0.4 composition. The dielectric values of the composite were gradually increased upon increasing the temperature, followed by a sharp change observed at 440 K. The electrical modulus of the sample was decreased with the increase of temperature and exhibits a single relaxation.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Recent Developments and Challenges in Hybrid Solid Electrolytes for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have attracted worldwide research interest due to their high energy density and long cycle life. Solid-state LIBs improve the safety of conventional liquid-based LIBs by replacing the flammable organic electrolytes with a solid electrolyte. Among the various types of solid electrolytes, hybrid solid electrolytes (HSEs) demonstrate great promise to achieve high ionic conductivity, reduced interfacial resistance between the electrolyte and electrodes, mechanical robustness, and excellent processability due to the combined advantages of both polymer and inorganic electrolyte. This article summarizes recent developments in HSEs for LIBs. Approaches for the preparation of hybrid electrolytes and current understanding of ion-transport mechanisms are discussed. The main challenges including unsatisfactory ionic conductivity and perspectives of HSEs for LIBs are highlighted for future development. The present review provides insights into HSE development to allow a more efficient and target-oriented future endeavor on achieving high-performance solid-state LIBs.

25 ENERGY STORAGE↗
DOE OSTI2015

Exogenous contrast agents for thermoacoustic imaging: An investigation into the underlying sources of contrast

Purpose: Thermoacoustic imaging at microwave excitation frequencies is limited by the low differential contrast exhibited by high water content tissues. To overcome this, exogenous thermoacoustic contrast agents based on gadolinium compounds, iron oxide, and single wall carbon nanotubes have previously been suggested and investigated. However, these previous studies did not fully characterize the electric, magnetic, and thermodynamic properties of these agents thus precluding identification of the underlying sources of contrast. To address this, measurements of the complex permittivity, complex permeability, DC conductivity, and Grüneisen parameter have been made. These measurements allowed the origins of the contrast provided by each substance to be identified. Methods: The electric and magnetic properties of the contrast agents were characterized at 3 GHz using two rectangular waveguide cavities. The DC conductivity was measured separately using a conductivity meter. Thermoacoustic signals were then acquired and compared to those generated in water. Finally, 3D electromagnetic simulations were used to decouple the different contributions to the absorbed power density. Results: It was found that the gadolinium compounds provided appreciable electric contrast but not originating from the gadolinium itself. The contrast was either due to dissociation of the gadolinium salt which increased ionic conductivity or its nondissociated polar fraction which increased dielectric polarization loss or a combination of both. In addition, very high concentrations were required to achieve appreciable contrast, to the extent that the Grüneisen parameter increased significantly and became a source of contrast. Iron oxide particles were found to produce low but measurable dielectric contrast due to dielectric polarization loss, but this is attributed to the coating of the particles not the iron oxide. Single wall carbon nanotubes did not provide measurable contrast of any type. Conclusions: It is concluded that gadolinium based contrast agents, iron oxide particles, and single walled carbon nanotubes have little intrinsic merit as thermoacoustic contrast agents. Simple electrolytes such as saline which yield high contrast based on ionic conductivity provide much higher dielectric contrast per unit solute concentration and are likely to be significantly more effective as contrast agents.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Electrical Conductivity of Cancrinite-Type Na{sub 8−2x}Ca{sub x}[Al{sub 6}Si{sub 6}O{sub 24}][CO{sub 3}] · 2H{sub 2}O (x ≤ 0.03) Crystals

The electrical conductivity of crystals of artificial cancrinite Na{sub 8−2x}Ca{sub x}[Al{sub 6}Si{sub 6}O{sub 24}][CO{sub 3}] · 2H{sub 2}O (x ≤ 0.03) has been studied in the temperature range of 498−604 K. These crystals were grown by hydrothermal synthesis on a seed in the Na{sub 2}O–Al{sub 2}O{sub 3}–SiO{sub 2}–H{sub 2}O system (t = 380−420°С, P = 3 × 10{sup 7}−9 × 10{sup 7} Pa). The ionic conductivity of a single-crystal sample (sp. gr. P6{sub 3}), measured along the crystallographic axis c, is low: σ = 8 × 10{sup –7} S/cm at 300°С. The electric transport activation energy is E{sub a} = 0.81 ± 0.05 eV. The relationship between the ionic conductivity and specific features of the atomic structure of cancrinites is discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗