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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Surfactant Effects in Porous Electrodes for Microemulsion Redox Flow Batteries

The effect of surfactant additives on electrochemical behavior in porous electrodes was investigated using vanadium redox flow battery half-cells and the dependence of volumetric kinetics and mass transport on electrolyte, surfactant, and electrode type was explored. Without surfactant added, carbon paper electrodes demonstrated greater kinetics and transport compared to carbon felt, for a given electrolyte. Additionally, posolyte kinetics are greater than negolyte kinetics by one to three orders of magnitude, depending on the electrode type. Addition of surfactant increased electrode wettability and possibly electrochemical surface area. However, this was accompanied by a decrease in volumetric mass transport, due to stronger electrolyte-electrode interactions. The presence of sodium dodecyl sulfate (SDS) influenced posolyte and negolyte kinetics differently. Kinetics showed a dependence on electrode type and surfactant. On carbon felt, volumetric kinetics decreased for both posolyte and negolyte with SDS addition. On carbon paper, SDS decreased volumetric kinetics for the posolyte but increased (>2X) kinetics for the negolyte! This kinetic enhancement depends on surfactant chemistry: cetyltrimethylammonium bromide, a cationic surfactant, failed to increase kinetics. Furthermore, SDS did not increase areal specific resistance. Furthermore, these findings show the superior performance of carbon paper compared to carbon felt and suggest SDS as a possible VRFB negolyte additive.

25 ENERGY STORAGE↗
DOE OSTI2024

Electrochemical Reactivity of Hydrogen Storage Materials: Exploring Borohydride and Hydrazinium Salt Mixtures

Electrochemical characterization of hydrogen storage materials was conducted in a non-aqueous environment to investigate the direct electrochemical release and consumption of hydrogen and the potential for regeneration. We first address the challenge of minimal solubility of the synthetic precursors, sodium borohydride (NaBH 4 ) and hydrazinium bromide (N 2 H 5 Br), in both organic and inorganic solvents. We next determine and calibrate a reference electrode formulation compatible with our non-aqueous media and analytes that demonstrates a stable reference potential. We employ cyclic voltammetry (CV) to characterize the precursors and mixtures thereof. Each CV peak is assigned to a corresponding electrochemical reaction. Using the rate-dependent CV method and Randles–Ševčík equation, we calculate the diffusion coefficient of each chemical (NaBH 4 and N 2 H 5 Br). Analysis of the CVs, coupled with 11B NMR analysis, reveals a room temperature chemical transformation of NaBH 4 and N 2 H 5 Br mixtures into hydrazine borane (N 2 H 4 BH 3 ). These results are particularly significant, considering the limited information available on the electrochemical characterization of metal borohydride and hydrazinium salt in non-aqueous media. This work establishes a foundation for adapting a non-aqueous electrochemical system to further study the borohydride family of chemistries and to design and develop electrochemical devices for direct electrical and chemical energy interconversion with hydrogen storage materials.

08 HYDROGEN↗
DOE OSTI2025

Harnessing Redox-Active Molecules in Alkylammonium Halide-Based Eutectic Solvents for Redox Flow Batteries

Redox flow batteries (RFBs) are promising for large-scale energy storage, however, advancements in performance and cost-effectiveness are critical factors for adoption. Here we report on alkylammonium halide based eutectic solvents (ESs) and found that a ESs comprising of diethylammonium chloride or bromide, in ethylene glycol demonstrated exceptional stability and a wide electrochemical stability window, making it a promising candidate for RFB applications. The electrochemical stability and redox behavior of the alkylammonium halide-based ESs are significantly influenced by hydrogen-bonding interactions, modulated by the alkyl chain length of the cation and the nature of the anion. A redox-active eutectic electrolyte containing 0.45 M methyl viologen dichloride (MV 2+ ) paired with acetylferrocene exhibited reversible redox behavior with a maximum open-circuit voltage of ∼1.34 V. The first redox couple, representing the viologen dication to radical cation transition, exhibited remarkable stability with consistent performance, achieving an energy efficiency near 70% at charge-discharge current densities of 10 mA cm −2 over 160 cycles with about 3% loss of the initial capacity. This study highlights the potential of alkylammonium halide DES systems for implementing eutectic-based RFB technologies in the future.

25 ENERGY STORAGE↗
DOE OSTI2021

Classification of Semiconductors Using Photoluminescence Spectroscopy and Machine Learning

Photoluminescence spectroscopy is a nondestructive optical method that is widely used to characterize semiconductors. In the photoluminescence process, a substance absorbs photons and emits light with longer wavelengths via electronic transitions. This paper discusses a method for identifying substances from their photoluminescence spectra using machine learning, a technique that is efficient in making classifications. Neural networks were constructed by taking simulated photoluminescence spectra as the input and the identity of the substance as the output. Here, six different semiconductors were chosen as categories: gallium oxide (Ga 2 O 3 ), zinc oxide (ZnO), gallium nitride (GaN), cadmium sulfide (CdS), tungsten disulfide (WS 2 ), and cesium lead bromide (CsPbBr 3 ). The developed algorithm has a high accuracy (>90%) for assigning a substance to one of these six categories from its photoluminescence spectrum and correctly identified a mixed Ga 2 O 3 /ZnO sample.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

NANO.PTML model for read-across prediction of nanosystems in neurosciences. computational model and experimental case of study

Abstract Neurodegenerative diseases involve progressive neuronal death. Traditional treatments often struggle due to solubility, bioavailability, and crossing the Blood-Brain Barrier (BBB). Nanoparticles (NPs) in biomedical field are garnering growing attention as neurodegenerative disease drugs (NDDs) carrier to the central nervous system. Here, we introduced computational and experimental analysis. In the computational study, a specific IFPTML technique was used, which combined Information Fusion (IF) + Perturbation Theory (PT) + Machine Learning (ML) to select the most promising Nanoparticle Neuronal Disease Drug Delivery (N2D3) systems. For the application of IFPTML model in the nanoscience, NANO.PTML is used. IF-process was carried out between 4403 NDDs assays and 260 cytotoxicity NP assays conducting a dataset of 500,000 cases. The optimal IFPTML was the Decision Tree (DT) algorithm which shown satisfactory performance with specificity values of 96.4% and 96.2%, and sensitivity values of 79.3% and 75.7% in the training (375k/75%) and validation (125k/25%) set. Moreover, the DT model obtained Area Under Receiver Operating Characteristic (AUROC) scores of 0.97 and 0.96 in the training and validation series, highlighting its effectiveness in classification tasks. In the experimental part, two samples of NPs (Fe 3 O 4 _A and Fe 3 O 4 _B) were synthesized by thermal decomposition of an iron(III) oleate (FeOl) precursor and structurally characterized by different methods. Additionally, in order to make the as-synthesized hydrophobic NPs (Fe 3 O 4 _A and Fe 3 O 4 _B) soluble in water the amphiphilic CTAB (Cetyl Trimethyl Ammonium Bromide) molecule was employed. Therefore, to conduct a study with a wider range of NP system variants, an experimental illustrative simulation experiment was performed using the IFPTML-DT model. For this, a set of 500,000 prediction dataset was created. The outcome of this experiment highlighted certain NANO.PTML systems as promising candidates for further investigation. The NANO.PTML approach holds potential to accelerate experimental investigations and offer initial insights into various NP and NDDs compounds, serving as an efficient alternative to time-consuming trial-and-error procedures.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Transport and Retention of Particulate Organic Matter in Sand: Lab Experiments and Modelling

Flow-through reactor (FTR) experiments were conducted at three different downward vertical flow rates to study the transport and retention of particulate organic matter (Chlorella powder) in riverbed sediments. This data package includes data files (.csv) regarding effluent collected from the FTRs during the experiments (time, duration, volume of each sample collection; concentration of nonreactive bromide tracer; concentration of suspended Chlorella determined by absorbance measurements) and sediment (sand) slices collected from the FTRs after the experiments (mass of Chlorella retained in 1 cm depth intervals determined by loss-on-ignition method). More detailed descriptions of data are provided in the data dictionary, and detailed methods are available in the associated MSc thesis listed in ‘Related References.’ The data dictionary and file level meta data (FLMD) are included in the data package as both .csv and .xlsx files. This data package also includes timelapse videos (.mp4) of the experiments, and modelling scripts associated with the experiments. The modelling scripts are included as MATLAB ‘live scripts’ (.mlx, which can be run using MATLAB), and are also included as .pdf and .html files with output plots included (which can be viewed without a MATLAB license and installation). The data files and modelling scripts are organized into a .zip folder for each of the three FTR experiments (three flow rates).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Solute chemistry for streams draining geomorphic features and varying land cover gradients in the East River watershed, Colorado

This dataset contains solute chemistry data and GPS coordinates for surface water samples collected in the East River watershed in the Elk and West Elk Ranges of Colorado from August 3rd through August 11th, 2022. Samples were collected from streams and groundwater seeps as part of a comprehensive analysis within the watershed of how different geomorphic features (such as landslides and rock glaciers) along with variations in land cover (such as the presence of vegetation) affect stream water quality in this Rocky Mountain headwater environment. This dataset includes concentrations of the following in a single csv file: fluoride, chloride, sulfate, nitrate, calcium, potassium, magnesium, sodium, silicon, and total organic carbon (TOC). All concentrations are reported in mg/L. The sulfate data in this version have been updated to account for an earlier ion chromatograph instrument method error whereby sulfate and bromide peaks overlapped in calibration solution samples, biasing calculated sulfate concentrations low by 30-50%. Sulfate data reported herein are from a re-run of the samples performed in December 2024 using a corrected instrument method. All samples were stored under refrigerated conditions and filtered on initial collection.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Lowering oxygen evolution overpotential via morphology control of NiO x nanocatalysts

NiO x nanocatalysts with two distinct morphologies, nano-spindles and nano-plates, were synthesized and evaluated for oxygen evolution reaction (OER) performance. Spindle-like NiO x was prepared via a hydrothermal reaction of nickel nitrate and urea with cetyltrimethylammonium bromide as a surfactant at 120 °C for 24 h, forming Ni(OH) 2 -based intermediates that were subsequently calcined at 300 °C for 3 h. In contrast, platelet-like Ni(OH) 2 nanocrystals were obtained using nickel(II) acetate and KOH at 180 °C for 24 h, followed by calcination at 400 °C or 500 °C for 4 h to yield NiO x nano-plates. The NiO x nano-spindles exhibited an OER overpotential of 395 mV at 10 mA/cm 2 , whereas the NiO x nano-plates annealed at 400 °C and 500 °C showed overpotentials of 565 mV and 474 mV at 10 mA/cm 2 , respectively. Structural characterization and X-ray photoemission spectroscopy indicate these differences arise from morphology-dependent surface structures that govern catalytic activity.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnBr4 by Materials Project

SnBr4 is Silicon tetrafluoride-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four tin(iv) bromide molecules. Sn4+ is bonded in a tetrahedral geometry to four Br1- atoms. All Sn–Br bond lengths are 2.48 Å. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Sn4+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Sn4+ atom. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Sn4+ atom. In the fourth Br1- site, Br1- is bonded in a single-bond geometry to one Sn4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CBrN by Materials Project

BrCN is Cyanogen Chloride structured and crystallizes in the orthorhombic Pmmn space group. The structure is zero-dimensional and consists of two cyanogen bromide molecules. C4+ is bonded in a linear geometry to one N3- and one Br1- atom. The C–N bond length is 1.17 Å. The C–Br bond length is 1.79 Å. N3- is bonded in a single-bond geometry to one C4+ atom. Br1- is bonded in a distorted single-bond geometry to one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SBr2O by Materials Project

SOBr2 crystallizes in the orthorhombic Pca2_1 space group. The structure is zero-dimensional and consists of eight thionyl bromide molecules. S2- is bonded in a distorted single-bond geometry to one O2- and two Br2+ atoms. The S–O bond length is 1.46 Å. There are one shorter (2.28 Å) and one longer (2.31 Å) S–Br bond lengths. O2- is bonded in a single-bond geometry to one S2- atom. There are two inequivalent Br2+ sites. In the first Br2+ site, Br2+ is bonded in a single-bond geometry to one S2- atom. In the second Br2+ site, Br2+ is bonded in a single-bond geometry to one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnH8(BrO2)2 by Materials Project

MnH8(O2Br)2 is alpha U structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four manganese(ii) bromide tetrahydrate molecules. Mn2+ is bonded in an octahedral geometry to four O2- and two Br1- atoms. There are a spread of Mn–O bond distances ranging from 2.19–2.29 Å. There are one shorter (2.66 Å) and one longer (2.70 Å) Mn–Br bond lengths. There are eight inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Mn2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Mn2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to one Mn2+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Mn2+ and two H1+ atoms. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Mn2+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SeBr by Materials Project

SeBr crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four selenium bromide (se2br2) molecules. there are two inequivalent Se sites. In the first Se site, Se is bonded in a water-like geometry to one Se and one Br atom. The Se–Se bond length is 2.24 Å. The Se–Br bond length is 2.42 Å. In the second Se site, Se is bonded in a water-like geometry to one Se and one Br atom. The Se–Br bond length is 2.44 Å. There are two inequivalent Br sites. In the first Br site, Br is bonded in a single-bond geometry to one Se atom. In the second Br site, Br is bonded in a single-bond geometry to one Se atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg3As8(S4Br3)2 by Materials Project

(HgBr2)2HgAs8(S4Br)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four mercuric bromide molecules and two HgAs8(S4Br)2 clusters. In each HgAs8(S4Br)2 cluster, Hg2+ is bonded in a distorted linear geometry to four S2- and two equivalent Br1- atoms. There are two shorter (3.29 Å) and two longer (3.35 Å) Hg–S bond lengths. Both Hg–Br bond lengths are 2.50 Å. There are four inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.27 Å. In the second As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.26 Å. In the third As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.26 Å. In the fourth As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.26 Å) and one longer (2.28 Å) As–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 2-coordinate geometry to two As2+ atoms. In the second S2- site, S2- is bonded in a distorted water-like geometry to two As2+ atoms. In the third S2- site, S2- is bonded in a distorted water-like geometry to one Hg2+ and two As2+ atoms. In the fourth S2- site, S2- is bonded in a distorted water-like geometry to one Hg2+ and two As2+ atoms. Br1- is bonded in a single-bond geometry to one Hg2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlSBr3N by Materials Project

AlBr3NS crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two 1,3,2,4-dithiadiazetidine molecules and four aluminum bromide molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlSeBr3N by Materials Project

AlBr3NSe crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two 1,3,2,4-diselenadiazetidine molecules and four aluminum bromide molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SeBr by Materials Project

SeBr crystallizes in the orthorhombic Aea2 space group. The structure is zero-dimensional and consists of four selenium bromide (se2br2) molecules. Se is bonded in a distorted water-like geometry to one Se and one Br atom. The Se–Se bond length is 2.27 Å. The Se–Br bond length is 2.42 Å. Br is bonded in a single-bond geometry to one Se atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Fe3C8(Br2N)8 by Materials Project

(FeBr4)2FeC6(NBr)6(BrCN)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two cyanogen bromide molecules, two tetrabromoiron molecules, and one FeC6(NBr)6 cluster. In the FeC6(NBr)6 cluster, Fe+2.67+ is bonded in an octahedral geometry to six N3- atoms. There are a spread of Fe–N bond distances ranging from 1.93–1.95 Å. There are three inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a linear geometry to one N3- and one Br1- atom. The C–N bond length is 1.17 Å. The C–Br bond length is 1.79 Å. In the second C4+ site, C4+ is bonded in a linear geometry to one N3- and one Br1- atom. The C–N bond length is 1.17 Å. The C–Br bond length is 1.79 Å. In the third C4+ site, C4+ is bonded in a linear geometry to one N3- and one Br1- atom. The C–N bond length is 1.17 Å. The C–Br bond length is 1.79 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Fe+2.67+ and one C4+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Fe+2.67+ and one C4+ atom. In the third N3- site, N3- is bonded in a linear geometry to one Fe+2.67+ and one C4+ atom. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one C4+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one C4+ atom. In the third Br1- site, Br1- is bonded in a distorted single-bond geometry to one C4+ atom.

36 MATERIALS SCIENCE↗