Search NASA⌕ Search

SEARCH · Search NASA

Results for “vanadium”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Single Crystals of Vanadium Oxides as a Lens for Understanding Structural and Electronic Phase Transformations, Ion Transport, Chemo-Mechanical Coupling, and Electrothermal Neuronal Emulation

Vanadium oxides cystallize in a diverse array of structures and compositions arising from the redox versatility of vanadium, variable covalency of V−O bonds, and myriad coordination geometries. Their open frameworks present abundant interstitial sites that enable insertion of guest-ions. In such compounds, V3d electron and spin localization and disorder couple strongly to structural preferences. The rich structural diversity manifests as a “rugged” free energy landscape with multiple interconvertible polymorphs. Such a landscape sets up structural, electronic, and magnetic transitions that underpin the promise of these materials as ion-insertion battery electrodes; compact primitives for brain-inspired computing, and heterogeneous catalysts. Here, we examine the structural and compositional diversity, electronic instabilities, defect dynamics, structure transformations, mechanical properties, and surface structure of vanadium oxides using single crystals as a distinctive lens. Single crystals enable the measurement of structure−function correlations without the ensemble and orientational averaging inevitable in polycrystalline materials. Their well-defined surfaces further enable examination of facet-dependent reactivity toward molecular adsorbates, ion fluxes, and lattice (mis)matched solids. We provide a comprehensive account of vanadium-oxide single-crystal studies, from delineation of common structural motifs to single-crystal growth techniques, topochemical modification strategies, mechanisms underpinning electronic instabilities, and implementation as electrothermal neurons and battery electrode materials.

Ponis, John [Texas A&M University, College Station↗
DOE OSTI2018

Catalytic Applications of Vanadium: A Mechanistic Perspective

The chemistry of vanadium has seen remarkable activity in the past SO years. In the present review, reactions catalyzed by homogeneous and supported vanadium complexes from 2008 to 2018 are summarized and discussed. Here particular attention is given to mechanistic and kinetics studies of vanadium-catalyzed reactions including oxidations of alkanes, alkenes, arenes, alcohols, aldehydes, ketones, and sulfur species, as well as oxidative C-C and C-O bond cleavage, carbon carbon bond formation, deoxydehydration, haloperoxidase, cyanation, hydrogenation, dehydrogenation, ring-opening metathesis polymerization, and oxo/imido heterometathesis. Additionally, insights into heterogeneous vanadium catalysis are provided when parallels can be drawn from the homogeneous literature.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Biotransformations of antidiabetic vanadium prodrugs in mammalian cells and cell culture media: A XANES spectroscopic study

The antidiabetic activities of vanadium(V) and -(IV) prodrugs are determined by their ability to release active species upon interactions with components of biological media. The first X-ray absorption spectroscopic study of the reactivity of typical vanadium (V) antidiabetics, vanadate ([V V O 4 ] 3– , A) and a vanadium(IV) bis(maltolato) complex (B), with mammalian cell cultures has been performed using HepG2 (human hepatoma), A549 (human lung carcinoma), and 3T3-L1 (mouse adipocytes and preadipocytes) cell lines, as well as the corresponding cell culture media. X-ray absorption near-edge structure data were analyzed using empirical correlations with a library of model vanadium(V), -(IV), and -(III) complexes. Both A and B ([V] = 1.0 mM) gradually converged into similar mixtures of predominantly five- and six-coordinate VV species (~75% total V) in a cell culture medium within 24 h at 310 K. Speciation of V in intact HepG2 cells also changed with the incubation time (from ~20% to ~70% V IV of total V), but it was largely independent of the prodrug used (A or B) or of the predominant V oxidation state in the medium. Subcellular fractionation of A549 cells suggested that V V reduction to V IV occurred predominantly in the cytoplasm, while accumulation of V V in the nucleus was likely to have been facilitated by noncovalent bonding to histone proteins. The nuclear V V is likely to modulate the transcription process and to be ultimately related to cell death at high concentrations of V, which may be important in anticancer activities. Mature 3T3-L1 adipocytes (unlike for preadipocytes) showed a higher propensity to form V IV species, despite the prevalence of V V in the medium. Lastly, the distinct V biochemistry in these cells is consistent with their crucial role in insulin-dependent glucose and fat metabolism and may also point to an endogenous role of V in adipocytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Graphene-modified nanostructured vanadium pentoxide hybrids with extraordinary electrochemical performance for Li-ion batteries

The long-standing issues of low intrinsic electronic conductivity, slow lithium-ion diffusion and irreversible phase transitions on deep discharge prevent the high specific capacity/energy (443 mAh g -1 and 1,550 Wh kg -1 ) vanadium pentoxide from being used as the cathode material in practical battery applications. Here we develop a method to incorporate graphene sheets into vanadium pentoxide nanoribbons via the sol–gel process. The resulting graphene-modified nanostructured vanadium pentoxide hybrids contain only 2 wt. % graphene, yet exhibits extraordinary electrochemical performance: a specific capacity of 438 mAh g -1 , approaching the theoretical value (443 mAh g -1 ), a long cyclability and significantly enhanced rate capability. Such performance is the result of the combined effects of the graphene on structural stability, electronic conduction, vanadium redox reaction and lithium-ion diffusion supported by various experimental studies. Finally, this method provides a new avenue to create nanostructured metal oxide/graphene materials for advanced battery applications.

25 ENERGY STORAGE↗
DOE OSTI2021

Thin-film synthesis of superconductor-on-insulator A15 vanadium silicide

Abstract We present a new method for thin-film synthesis of the superconducting A15 phase of vanadium silicide with critical temperature higher than 13 K. Interdiffusion between a metallic vanadium film and the underlying silicon device layer in a silicon-on-insulator substrate, at temperatures between 650 and 750 °C, favors formation of the vanadium-rich A15 phase by limiting the supply of available silicon for the reaction. Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction verify the stoichiometry and structure of the synthesized thin films. We measure superconducting critical currents of more than 10 6 amperes per square centimeter at low temperature in micron-scale bars fabricated from the material, and an upper critical magnetic field of 20 T, from which we deduce a superconducting coherence length of 4 nm, consistent with previously reported bulk values. The relatively high critical temperature of A15 vanadium silicide is an appealing property for use in silicon-compatible quantum devices and circuits.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Acoustoelectric drag current in vanadium oxide films

Two different Mott insulator wires, vanadium dioxide and vanadium sesquioxide, were prepared on the piezoelectric LiNbO 3 substrates. Coupling of acoustic waves propagating in LiNbO 3 with free carriers in vanadium oxide gives rise to the acoustoelectric effect that manifests itself as the generation of direct electric current by the acoustic wave. According to a phenomenological model, the value of the effect strongly depends on the wires conductivity, which, for the vanadium-oxide films, changes by a few orders of magnitude. We demonstrated that this yields a significant enhancement of the direct current (DC) current generated in the wires at the metal–insulator transition temperatures. The sign of the generated DC voltage is different for excitations by surface and bulk acoustic wave modes, which may happen due to reverse wave propagation at the substrate surface. For each resonance mode, polarities of the generated DC signal are the same in both wires, despite the signs of charge carriers being different for these materials. It was shown that two complementary techniques (acoustoelectric and Hall effect measurements) yield opposite signs of charge carriers in VO 2 .

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

Density Functional Theory Analysis of Candidate Tritium Permeation Barriers for Vanadium Alloys as a Fusion Structural Material

Vanadium alloys are being considered as a candidate structural material for the breeder blanket component of future fusion reactors due to their good thermal conductivity, low activation, and chemical compatibility with FLiBe. However, vanadium has a high hydrogen solubility, resulting in hydrogen diffusion and trapping in the vanadium structural alloy and lower than expected tritium breeding ratios. To mitigate the permeation of hydrogen into the structural alloy, a tritium permeation barrier will be coated onto the vanadium alloy. Multiple materials have been proposed as candidate tritium permeation barriers, but the extent to which each of these materials impacts hydrogen diffusion and trapping is still unknown. In this project, we perform atomic-scale calculations to narrow down the list of potential tritium permeation barrier candidates and to understand the mechanisms through which hydrogen diffusion is affected in these materials.

36 MATERIALS SCIENCE↗
NASA NTRS2010

Oxidation States of Grim Glasses in EET79001 Based on Vanadium Valence

Gas-rich impact-melt (GRIM) glasses in SNC meteorites are very rich in Martian atmospheric noble gases and sulfur suggesting a possible occurrence of regolith-derived secondary mineral assemblages in these samples. Previously, we have studied two GRIM glasses, 506 and 507, from EET79001 Lith A and Lith B, respectively, for elemental abundances and spatial distribution of sulfur using EMPA (WDS) and FE-SEM (EDS) techniques and for sulfur-speciation using K-edge XANES techniques. These elemental and FE-SEM micro-graph data at several locations in the GRIM glasses from Shergotty (DBS), Zagami 994 and EET79001, Lith B showed that FeO and SO3 are positively correlated (SO3 represents a mixture of sulfide and sulfate). FE-SEM (EDS) study revealed that the sulfur-rich pockets in these glasses contain numerous micron-sized iron-sulfide (Fe-S) globules sequestered throughout the volume. However, in some areas (though less frequently), we detected significant Fe-S-O signals suggesting the occurrence of iron sulfate. These GRIM glasses were studied by K-edge microXANES techniques for sulfur speciation in association with iron in sulfur-rich areas. In both samples, we found the sulfur speciation dominated by sulfide with minor oxidized sulfur mixed in with various proportions. The abundance of oxidized sulfur was greater in 506 than in 507. Based on these results, we hypothesize that sulfur initially existed as sulfate in the glass precursor materials and, on shock-impact melting of the precursor materials producing these glasses, the oxidized sulfur was reduced to predominately sulfide. In order to further test this hypothesis, we have used microXANES to measure the valence states of vanadium in GRIM glasses from Lith A and Lith B to complement and compare with previous analogous measurements on Lith C (note: 506 and 507 contain the largest amounts of martian atmospheric gases but the gas-contents in Lith C measured by are unknown). Vanadium is ideal for addressing this re-dox issue because it has multiple valence states and is a well-studied element. Ferrous-dominated iron valences determined by microXANES on the Lith A and Lith B glasses provide little redox sensitivity. Vanadium valence measurements for impact glass in Lith C at three different locations yielded valence values of 3.1, 3.2 and 3.4 with inferred fO2 values of IW-0.7, IW-0.1 and IW+0.7, respectively. This range of oxygen-fugacity values is understandable because the glasses are shock-molten impact glasses which are heterogeneous in nature. Oxygen fugacity values obtained from the analysis of Fe-Ti oxides and Eu partitioning in pyroxenes from EET79001 Lith A and Lith B (host lithologies) were in the range of IW+0.3 to IW+1.9 suggesting that V in the Lith C impact glass was reduced in the impact process. Here, we examine whether the 506 from Lith A and 507 from Lith B GRIM glasses yield similar or different fO2 values from those of Lith C using the vanadium K-edge microXANES technique.

Sutton, S. R.↗
DOE OSTI2022

Vanadium metal-organic framework for selective adsorption

A permanently porous vanadium(II)-containing metal-organic framework (MOF) with vanadium(II) centers and methods for synthesis of such MOF frameworks are provided. Methods for using such compounds to selectively react with N2 over CH4 are provided. In the synthetic methods, a vanadium source, such as VY2(tmeda)2, where Y is a halogen and tmeda is N,N,N′,N′-tetramethylethane-1,2-diamine and a H2(ligand) are reacted in the presence of acid in a solvent at between 110° C. and 130° C. to form an intermediate product. The intermediate product is collected and washed with a washing agent, such as DMF and acetonitrile, and the vanadium(II) based MOF is activated by heating the washed intermediate product to at least 160° C. under dynamic vacuum.

Long, Jeffrey R.↗
DOE OSTI2019

Surface Characteristics and Hardness Variations in Electrical Discharge Machining of Enhanced Nitrogen in Vanadium Steels

Enhanced nitrogen in steels containing vanadium causes fine precipitates of vanadium nitride, which improve the hardenability properties. However, understanding the response of such steels to electrical discharge machining (EDM) is incomplete and needs further investigation. Therefore, EDM of enhanced nitrogen in steels containing vanadium was compared with a similar compositional steel that was free of nitrogen. The surface morphology, microstructural alterations, microhardness variation, and compositional depth profiling of the samples machined by EDM in oil and deionized water dielectric liquids were examined. Microscopic studies were carried out using optical and scanning electron microscopy. Phases were identified by X-ray diffractometry, and elemental depth profiling was performed using glow discharge optical emission spectroscopy. The hardness of the resolidified and heat-affected layers was measured using a Vickers type microhardness tester. The results of this study revealed that the dissolved nitrogen in steel decreased the probability of surface cracks and resulted in a softer resolidified layer structure when machining in the oil dielectric liquid. Thus, the presence of nitrogen reduced the formation of tension-induced martensite in the resolidified layer. Moreover, the heat-affected zone below the resolidified layer exhibited a uniform and harder structure, compared with the steel without nitrogen content, indicating the fast nature of the thermal cycles in EDM. The free nitrogen in steel did not dissociate during sparking; therefore, precipitation strengthening occurred in the heat-affected zone.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Plasma assisted synthesis of vanadium pentoxide nanoplates

In this work, we report the growth of α-V{sub 2}O{sub 5} (orthorhombic) nanoplates on glass substrate using plasma assisted sublimation process (PASP) and Nickel as catalyst. 100 nm thick film of Ni is deposited over glass substrate by thermal evaporation process. Vanadium oxide nanoplates have been deposited treating vanadium metal foil under high vacuum conditions with oxygen plasma. Vanadium foil is kept at fixed temperature growth of nanoplates of V{sub 2}O{sub 5} to take place. Samples grown have been studied using XPS, XRD and HRTEM to confirm the growth of α-phase of V{sub 2}O{sub 5}, which revealed pure single crystal of α- V{sub 2}O{sub 5} in orthorhombic crystallographic plane. Surface morphological studies using SEM and TEM show nanostructured thin film in form of plates. Uniform, vertically aligned randomly oriented nanoplates of V{sub 2}O{sub 5} have been deposited.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Corrosion resistance investigation of vanadium alloys in liquid lithium

A major concern in using vanadium alloys for first wall/blanket systems in fusion reactors is their activity with regard to nonmetallic impurities in the coolants. This paper presents the results of studying the corrosion resistance in high-purity liquid lithium (with the nitrogen and carbon content of less than 10{sup –3} wt %) of vanadium and vanadium alloys (V–1.86Ga, V–3.4Ga–0.62Si, V–4.81Ti–4.82Cr) both in the initial state and preliminarily irradiated with Ar+ ions with energy of 20 keV to a dose of 10{sup 22} m{sup –2} at an irradiation temperature of ~400°C. The degree of corrosion was estimated by measuring the changes in the weight and microhardness. Corrosion tests were carried out under static isothermal conditions at a temperature of 600°C for 400 h. The identity of corrosion mechanisms of materials both irradiated with Ar ions and not irradiated, which consisted in an insignificant penetration of nitrogen into the materials and a substantial escape of oxygen from the materials, causing the formation of a zone with a reduced microhardness near the surface, was established. The influence of the corrosive action of lithium on the surface morphology of the materials under study was found, resulting in the manifestation of grain boundaries and slip lines on the sample surface, the latter being most clearly observed in the case of preliminary irradiation with Ar ions.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Vanadium and Nickel Distribution in Resin Fractions of High-Sulfur Heavy Oils

The mechanisms of occurrence and distribution of vanadium and nickel in resins and their fractions are studied with reference to high-sulfur heavy oils of Tatarstan, Samara Oblast (region), and Kazakhstan deposits. For all the investigated heavy oils, the content of vanadium and nickel in resins increase in direct proportion to the increase in contents of these metals in the oils. The resins were fractionated into benzene and alcohol-benzene fractions by adsorption chromatographic separation on silica gel. The alcohol-benzene fractions are characterized as being more polar on account of a larger content of oxygen-bearing structural groups. The special features of vanadium and nickel content and distribution in resin fractions are disclosed for heavy oils of various production complexes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Low-Temperature Magnetic Properties of Vanadium-Doped ZnO Nanoparticles

Low-temperature magnetic study of transition metal-doped ZnO nanoparticles tends to spring ambiguities of magnetic phases due to defect states, environment of doped ions, and anisotropy. Interestingly, vanadium doping in ZnO brings out versatile magnetic ordering which offers more room for basic understanding of the underlying mechanism. Vanadium-doped ZnO nanoparticles are prepared using a simple cost-effective approach of solution combustion method. Macroscopic and microscopic aspects of the samples have been unraveled using structural and morphological studies with the implications on the exhibited magnetic behavior. Development of antiferromagnetic, ferromagnetic, and ferrimagnetic interactions in the material illustrated by low-temperature magnetic measurements preludes the possible interplay of dopant-initiated defect correlation and morphological and interfacial secondary phases. The grain boundary reformation due to vanadium in the ZnO nanograins is exploited through a systematic correlation of structural and morphological studies in order to gain more insight into the portrayed magnetic signatures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Arsenic, vanadium, iron, and manganese biogeochemistry in a deltaic wetland, southern Louisiana, USA

Geochemical cycling of the redox-sensitive trace elements arsenic (As) and vanadium (V) was examined in shallow pore waters from a marsh in an interdistributary embayment of the lower Mississippi River Delta. In particular, we explore how redox changes with depth and distance from the Mississippi River affect As and V cycling in the marsh pore waters. Previous geophysical surveys and radon mass balance calculations suggested that Myrtle Grove Canal and bordering marsh receive fresh groundwater, derived in large part from seepage of the Mississippi River, which subsequently mixes with brackish waters of Barataria Bay. In addition, the redox geochemistry of pore waters in the wetlands is affected by Fe and S cycling in the shallow subsurface (0-20 cm). Sediments with high organic matter content undergo SO 4 2- reduction, a process ubiquitous in the shallow subsurface but largely absent at greater depths (~3 m). Instead, at depth, in the absence of organic-rich sediments, Fe concentrations are elevated, suggesting that reduction of Fe(III) oxides/oxyhydroxides buffers redox conditions. Arsenic and V cycling in the shallow subsurface are decoupled from their behavior at depth, where both V and As appear to be removed from solution by either diffusion or adsorption onto, or co-precipitation with, authigenic minerals within the deeper aquifer sediments. Pore water As concentrations are greatest in the shallow subsurface (e.g., up to 315 nmol kg -1 in the top ~20 cm of the sediment) but decrease with depth, reaching values <30 nmol kg -1 at depths between 3 and 4 m. Vanadium concentrations appear to be tightly coupled to Fe cycling in the shallow subsurface, but at depth, V may be adsorbed to clay or sedimentary organic matter (SOM). Diffusive fluxes are calculated to examine the export of trace elements from the shallow marsh pore waters to the overlying canal water that floods the marsh. The computed fluxes suggest that the shallow sediment serves as a source of Fe, Mn, and As to the surface waters, whereas the sediments act as a sink for V. Iron and Mn fluxes are substantial, ranging from 50 to 30,000 and 770 to 4,300 nmol cm -2 day -1 , respectively, whereas As fluxes are much less, ranging from 2.1 to 17 nmol cm -2 day -1 . Vanadium fluxes range from 3.0 nmol cm -2 day -1 directed into the sediment to 1.7 nmol cm -2 day -1 directed out of the sediment

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Bonding of vanadium- and Iron-based alloys as interlayers for plasma-facing and structural materials in fusion systems

Vanadium alloys and FeCrAl were investigated as interlayers between tungsten and reduced activation ferritic martensitic steel for fusion system components to avoid formation of intermetallic phase at operating temperatures between 550 and 1100 °C, while maintaining a body centered cubic phase throughout the interface. Physical and mechanical properties need to be graded between tungsten and steel, but recent results showed a significant hardness increase at the FeCrAl to vanadium alloy interface. Here, a sintered sample of these alloys was annealed for extended time, and the microstructure was investigated to provide a better understanding of the phenomena. A comparison with an additively manufactured interface of the same material is provided. An unexpected L2 1 intermetallic phase formation has been revealed using microscopy and synchrotron techniques and will inform future additive manufacturing approaches of the interface. A Cr layer interface as a preliminary solution was proposed between the Vanadium alloy and FeCrAl alloy interface.

Additive manufacturing↗
DOE OSTI2018

Tungsten-doped vanadium dioxide thin film based tunable antenna

Highlights: • VO{sub 2} and W-doped VO{sub 2} thin films were successfully synthesized by reactive PLD process. • By using the films, thermally tunable and switchable bowtie RF antenna structures were designed, fabricated, and tested. • The thin film based RF antenna structures were fully functional with a successful frequency tuning capability. - Abstract: Since vanadium dioxide (VO{sub 2}) is a phase change material that shows a metal to insulator transition behavior at a temperature near 68℃, it has many potential applications in the areas of science and engineering. In this study, tungsten (W) -doped VO{sub 2} thin films were synthesized by pulsed laser deposition (PLD) technique with a metallic vanadium target and W-wires which were simply attached on the surface of the vanadium target. Also, bowtie RF antenna structures were fabricated by using the films to check the frequency tunability. The experimental results show a decrease of the transition temperature and a broadening of the phase transition as the atomic percentage of W increases in the film structure. The results also reveal that the W-doped VO{sub 2} thin film based RF antenna was fully functional with the successful frequency tuning capability.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Structural and chemical evolutions of a magnesium vanadium oxide cathode under electrochemical cycling in magnesium batteries

The design of cathode materials that remain chemically and structurally stable during repetitive ion insertion and extraction poses a significant challenge in developing multivalent batteries. The cycling stability of traditional metal oxide-based cathode is challenged by sluggish diffusion of multivalent cations and parasitic reactivity at interfacial regimes, including the cathode electrolyte interphase layer (CEI). Understanding the reactions at the cathode-electrolyte interface, particularly those induced by non-stoichiometric surface layers, is a crucial design parameter for both cathode materials and electrolytes. Here, in this study, we employed multimodal analysis, including in situ and ex situ X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) to examine the surface reactions and subsequent structural and chemical evolutions of the CEI on high voltage magnesium vanadium oxide (MgV 2 O 4 ) spinel cathode during the Mg 2+ insertion/extraction processes. The results revealed that the presence of non-stoichiometric surface layers in the magnesium vanadium oxide cathode drive the decomposition of bis(trifluoromethanesulfonyl)imide (TFSI - ) anion, leading to the formation of the CEI layer. The CEI layer could inhibit the Mg 2+ ion transfer processes. Accompanying this reactivity-driven degradation, the magnesium vanadium oxide cathode undergoes pulverization, forming clusters of nanosized particles. This process likely improves cycling ability by creating new intercalation sites and shortening the diffusion pathway for the Mg 2+ cations. This study demonstrates that controlling surface stoichiometry and engineering morphological properties are critical design parameters for high performance cathodes for multivalent batteries.

25 ENERGY STORAGE↗