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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Hydrogen Storage with Aluminum Formate, ALF: Experimental, Computational, and Technoeconomic Studies

Long-duration storage of hydrogen is necessary for coupling renewable H 2 with stationary fuel cell power applications. In this work, aluminum formate (ALF), which adopts the ReO 3 -type structure, is shown to have remarkable H 2 storage performance at non-cryogenic (>120 K) temperatures and low pressures. The most promising performance of ALF is found between 120 K and 160 K and at 10 bar to 20 bar. The study illustrates H 2 adsorption performance of ALF over the 77 K to 296 K temperature range using gas isotherms, in situ neutron powder diffraction, and DFT calculations, as well as technoeconomic analysis (TEA), illustrating ALF’s competitive performance for long-duration storage versus compressed hydrogen and leading metal–organic frameworks. In the TEA, it is shown that ALF’s storage capacity, when combined with a temperature/pressure swing process, has advantages versus compressed H 2 at a fraction of the pressure (15 bar versus 350 bar). In conclusion, given ALF’s performance in the 10 bar to 20 bar regime under moderate cooling, it is particularly promising for use in safe storage systems serving fuel cells.

08 HYDROGEN↗
DOE OSTI2025

Hydrogen Storage with Aluminum Formate, ALF: Experimental, Computational, and Technoeconomic Studies

Long-duration storage of hydrogen is necessary for coupling renewable H2 with stationary fuel cell power applications. In this presentation, I will discuss how aluminum formate, Al(HCOO)3 (ALF), which adopts an ReO3-type structure, is shown to have remarkable H2 storage performance at non-cryogenic (> 120 K) temperatures and low pressures. The most promising performance of ALF is found between 120 K and 160 K and at 10 bar to 20 bar. The talk will cover and illustrate the H2 adsorption performance of ALF over the 77 K to 296 K temperature range using gas isotherms, in situ neutron powder diffraction, and DFT calculations, as well as technoeconomic analysis (TEA), illustrating ALF’s competitive performance for long-duration storage versus compressed hydrogen and leading metal–organic frameworks. In the TEA, it is shown that ALF’s storage capacity, when combined with a temperature/pressure swing process, has advantages versus compressed H2 at a fraction of the pressure (15 bar versus 350 bar). Given ALF’s performance in the 10 bar to 20 bar regime under moderate cooling, it is particularly promising for use in safe storage systems serving fuel cells, and is currently the only MOF that works in this moderate temperature range/ low pressure regime to be cost competitive with compressed H2 gas for large scale H2 storage.[1]

Chemistry↗
DOE OSTI2021

Comparison of AlF 3 thin films grown by thermal and plasma enhanced atomic layer deposition

Films of aluminum fluoride (AlF 3 ) deposited by thermal and plasma enhanced atomic layer deposition (PEALD) have been compared using in situ multiwavelength ellipsometry (MWE) and monochromatic x-ray photoelectron spectroscopy (XPS). The AlF 3 films were grown using cyclic exposures of trimethylaluminum, hydrogen fluoride, and H radicals from a remote H 2 inductively coupled plasma. Films were characterized in situ using MWE and XPS for growth rate, film composition, and impurity incorporation. The MWE showed a growth rate of 1.1 and 0.7 Å per cycle, at 100 °C, for thermal and plasma enhanced ALD AlF 3 films, respectively. Carbon incorporation was below the XPS detection limit. The plasma enhanced ALD AlF 3 film showed the presence of Al-Al chemical states, in the Al 2p scans, suggesting the presence of Al-rich clusters with a concentration of 14%. The Al-rich clusters are thought to originate during the hydrogen plasma step of the PEALD process. Finally, the Al-rich clusters were not detected in thermal ALD AlF 3 films using the same precursors and substrate temperature.

36 MATERIALS SCIENCE↗
NASA NTRS1994

Exotic fluoride molecules in IRC +10216: Confirmation of AlF and searches for MgF and CaF

Three new rotational transitions of aluminum fluoride (AlF) at 0.8 and 1.2 mm have been observed. The J = 10-9, J = 8-7, and J = 7-6 lines of AlF at 230, 263, and 329 GHz, respectively, were seen toward IRC +10216 using the Caltech Submillimter Observatory (CSO). Combined with the earlier data obtained for this species at IRAM at 2 and 3 mm, these measurements confirm the presence of the metal halide in this carbon-rich circumstellar shell. Analysis of the CSO and IRAM data suggests that AlF arises from a source with a diameter of theta(sub s) approximately = 5-10 sec and hence is present chiefly in the inner envelope of IRC +10216. In this region, the molecule has a column density of (0.3-1.1) x 10(exp 15)/sq cm, which indicates a fractional abundance of at least approximately 10(exp -9), relative to H2. Searches for the metal fluoride species CaF and MgF have also been conducted toward IRC +10216, but with negative results. The column density upper limits for MgF and CaF are N(sub tot) less than (1-4) x 10(exp 14)/sq cm. Relative abundances of these metal fluoride molecules can be understood in terms of chemical thermodynamic equilibrium. The presence of AlF in IRC +10216 also indicates that large quantities of fluorine must be present in the inner stellar envelope, suggesting that this element may be produced not primarily in explosive nucleosynthesis but rather in helium shell flashes, as indicated also by HF spectroscopy of red giant stars.

Ziurys, L. M.↗
NASA NTRS1988

Theoretical studies of AlF, AlCl, and AlBr

Spectroscopic constants have been obtained for the lowest six singlet and lowest five triplet states of AlF and AlCl. The results suggest that the correct ordering of the triplet manifold in these molecules is: a 3Pi, b 3Sigma(+), c 3Sigma(+), d 3Pi, and e 3Delta. Radiative lifetimes have been determined for the excited states, and the A 1Pi to X 1Sigma(+) transition in AlF, AlCl, and AlBr has been examined in detail. A-X transition moment functions, Einstein coefficients, and A 1Pi vibrational lifetimes have been obtained for AlF and AlCl.

Langhoff, Stephen R.↗
NASA NTRSDate not supplied

Environmental and Polarization Characterizations of E-Beam Plasma-Based AlF 3 -Passivated Aluminum Mirrors for Astronomical Telescopes

Astronomical space telescopes to study astrophysical phenomena from the far ultraviolet (FUV) to the near infrared (NIR) will require mirror coatings with high reflectance over this entire spectral region. While coatings for the optical and NIR part of the spectrum are fairly well developed with proven performance, the FUV range has presented significant challenges, particularly below 120nm. Recent developments in electron-beam (e-Beam) generated plasma treatment in a SF 6 environments has enabled the effective passivation of aluminum (Al) coatings for applications in the FUV, by native oxide removal and the formation of a AlF 3 passivation layer which could be tuned to any desired AlF 3 thickness. These results have been produced through a collaboration between the Goddard Space Flight Center (GSFC) and the Naval Research Laboratory (NRL). The passivation experiments have been carried out using the Large Area Plasma Processing System (LAPPS) at NRL using bare aluminum samples and provided by the coating group at GSFC. This novel procedure has demonstrated improved Al mirrors with state-of-the-art FUV reflectivity (e.g. R=91% at 121.6nm). In this paper, we will be reporting on environmental testing, micro-roughness, as well as polarization studies of these E-beam treated samples. These characterizations are being done in order to advance the Technology Readiness Level (TRL) for these Al+AlF 3 mirror coatings produced at LAPPS. The ultimate goal is to demonstrate the promise of using this coating technology to deliver reflectance performance plus stability and uniformity over a large area for a future IR/O/UV space telescope observatory.

FUV reflectance↗
DOE OSTI2021

Borderline first-order magnetic phase transition in AlFe 2 B 2

The thermal evolution of lattice parameters coupled with heat capacity data provide insight into tailorable magnetism-structure attributes in the orthorhombic compound AlFe 2 B 2 that was synthesized with and without small additions of gallium. Temperature-dependent X-ray powder diffraction experiments conducted through the magnetic phase transition reveal that the a- and b-parameters of both samples increase with increasing temperature while the c-parameter decreases. While a weak volumetric thermal expansion is noted over a range of temperatures well below and above the magnetic phase transition, anomalous behavior was observed within the phase transition region itself to reveal a magnetostructural phase transition with borderline first-order character in the Ga-modified sample but of more second-order character in the Ga-free sample. It is established that the nearest-neighbor Fe-Fe interatomic distance within the (ab)-plane plays a dominant role in influencing the magneto-functional response of these compounds. The magnetocaloric properties are discussed in the context of temperature-induced changes of the interatomic bonding that are influenced by the hypothesized presence of iron antisite defects in the AlFe 2 B 2 lattice.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on AlFe by Materials Project

FeAl is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Fe is bonded in a body-centered cubic geometry to eight equivalent Al atoms. All Fe–Al bond lengths are 2.49 Å. Al is bonded in a body-centered cubic geometry to eight equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlFe by Materials Project

FeAl crystallizes in the hexagonal P6/mmm space group. The structure is one-dimensional and consists of one FeAl ribbon oriented in the (0, 0, 1) direction. Fe is bonded in a distorted linear geometry to two equivalent Al atoms. Both Fe–Al bond lengths are 2.45 Å. Al is bonded in a distorted linear geometry to two equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc(AlFe)6 by Materials Project

Sc(FeAl)6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Sc is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.20 Å) and eight longer (3.25 Å) Sc–Fe bond lengths. There are a spread of Sc–Al bond distances ranging from 2.80–2.94 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Sc, four Fe, and six Al atoms. There are two shorter (2.47 Å) and two longer (2.48 Å) Fe–Fe bond lengths. There are two shorter (2.51 Å) and four longer (2.57 Å) Fe–Al bond lengths. In the second Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Sc, four equivalent Fe, and six Al atoms. There are four shorter (2.56 Å) and two longer (2.59 Å) Fe–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Sc, six Fe, and three Al atoms. There are one shorter (2.69 Å) and two longer (2.83 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Sc, six Fe, and one Al atom. The Al–Al bond length is 2.83 Å. In the third Al site, Al is bonded in a 6-coordinate geometry to two equivalent Sc, six Fe, and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf(AlFe)6 by Materials Project

Fe6Al6Hf crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Hf is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.19 Å) and eight longer (3.24 Å) Hf–Fe bond lengths. There are two shorter (2.82 Å) and six longer (2.93 Å) Hf–Al bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Hf, four Fe, and six Al atoms. There are two shorter (2.47 Å) and two longer (2.48 Å) Fe–Fe bond lengths. There are two shorter (2.50 Å) and four longer (2.57 Å) Fe–Al bond lengths. In the second Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Hf, four equivalent Fe, and six Al atoms. There are a spread of Fe–Al bond distances ranging from 2.55–2.60 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Hf, six Fe, and three Al atoms. There are one shorter (2.67 Å) and two longer (2.83 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Hf, six Fe, and one Al atom. The Al–Al bond length is 2.78 Å. In the third Al site, Al is bonded in a 6-coordinate geometry to two equivalent Hf, six Fe, and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlFe(WO4)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(AlFe)6 by Materials Project

Fe6Al6Zr crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Zr is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.19 Å) and eight longer (3.24 Å) Zr–Fe bond lengths. There are two shorter (2.82 Å) and six longer (2.94 Å) Zr–Al bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Zr, four Fe, and six Al atoms. There are two shorter (2.47 Å) and two longer (2.48 Å) Fe–Fe bond lengths. There are two shorter (2.50 Å) and four longer (2.57 Å) Fe–Al bond lengths. In the second Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Zr, four equivalent Fe, and six Al atoms. There are four shorter (2.57 Å) and two longer (2.60 Å) Fe–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Zr, six Fe, and three Al atoms. There are one shorter (2.67 Å) and two longer (2.82 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Zr, six Fe, and one Al atom. The Al–Al bond length is 2.78 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Zr, six Fe, and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho(AlFe)6 by Materials Project

HoFe6Al6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.21 Å) and eight longer (3.28 Å) Ho–Fe bond lengths. There are a spread of Ho–Al bond distances ranging from 2.85–3.01 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Ho, four Fe, and six Al atoms. All Fe–Fe bond lengths are 2.50 Å. There are two shorter (2.51 Å) and four longer (2.60 Å) Fe–Al bond lengths. In the second Fe site, Fe is bonded to two equivalent Ho, four equivalent Fe, and six Al atoms to form a mixture of distorted face, edge, and corner-sharing FeHo2Al6Fe4 cuboctahedra. There are two shorter (2.59 Å) and four longer (2.63 Å) Fe–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Ho, six Fe, and three Al atoms. There are one shorter (2.65 Å) and two longer (2.83 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Ho, six Fe, and one Al atom. The Al–Al bond length is 2.78 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Ho, six Fe, and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlFe(WO4)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(AlFe)6 by Materials Project

ErFe6Al6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Er is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.22 Å) and eight longer (3.27 Å) Er–Fe bond lengths. There are a spread of Er–Al bond distances ranging from 2.85–2.99 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Er, four Fe, and six Al atoms. All Fe–Fe bond lengths are 2.49 Å. There are two shorter (2.51 Å) and four longer (2.59 Å) Fe–Al bond lengths. In the second Fe site, Fe is bonded to two equivalent Er, four equivalent Fe, and six Al atoms to form a mixture of distorted corner, edge, and face-sharing FeEr2Al6Fe4 cuboctahedra. There are two shorter (2.58 Å) and four longer (2.62 Å) Fe–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Er, six Fe, and three Al atoms. There are one shorter (2.66 Å) and two longer (2.82 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Er, six Fe, and one Al atom. The Al–Al bond length is 2.78 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Er, six Fe, and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tb(AlFe)6 by Materials Project

TbFe6Al6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Tb is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.23 Å) and eight longer (3.28 Å) Tb–Fe bond lengths. There are a spread of Tb–Al bond distances ranging from 2.87–3.01 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Tb, four Fe, and six Al atoms to form a mixture of distorted face, edge, and corner-sharing FeTb2Al6Fe4 cuboctahedra. There are two shorter (2.49 Å) and two longer (2.50 Å) Fe–Fe bond lengths. There are two shorter (2.52 Å) and four longer (2.60 Å) Fe–Al bond lengths. In the second Fe site, Fe is bonded to two equivalent Tb, four equivalent Fe, and six Al atoms to form a mixture of distorted face, edge, and corner-sharing FeTb2Al6Fe4 cuboctahedra. There are a spread of Fe–Al bond distances ranging from 2.58–2.64 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Tb, six Fe, and three Al atoms. There are one shorter (2.66 Å) and two longer (2.82 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Tb and six Fe atoms. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tb, six Fe, and two equivalent Al atoms.

36 MATERIALS SCIENCE↗