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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Creating Favorable Pt/Co Interfaces via a Two‐Step Approach for Constructing Highly Durable PtCo Intermetallic Fuel Cell Catalysts

Structurally ordered PtCo intermetallics are one of the most promising oxygen-reduction catalysts in proton exchange membrane fuel cells (PEMFCs) due to their intrinsically improved catalytic activity and stability relative to PtCo solid-solution alloys. However, increasing the heating temperature to achieve a desirable high degree of ordering results in severe particle agglomeration and low mass activity and stability. Herein, a two-step synthesis approach is developed to create an L1 2 -Pt 3 Co intermetallic structure with an increased ordering degree and well-dispersed ultrafine particles. The first step of the synthesis yields ultrafine Pt nanoparticles that are well-dispersed on the ZIF-8-derived carbon support. The second adsorption step enables us to fine-tune the Pt and Co interfaces, assisted by optimal amino acids, to establish a favorable Co-rich environment around fine Pt nanoparticles, facilitating Co diffusion into the Pt crystalline under mild thermal conditions (<800 °C). In conclusion, this two-step ordered L1 2 -Pt 3 Co catalyst is systematically evaluated using membrane electrode assemblies under heavy-duty vehicle (HDV) conditions and demonstrated exceptional performance and durability, retaining 1.35 A cm -2 only a 7% loss in current density at 0.7 V after an extensive accelerated stress test of 150,000 voltage cycles.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2021

Identifying Boron Active Sites for the Oxidative Dehydrogenation of Propane

Oxidative dehydrogenation of propane (ODHP) to propylene could have a significant impact on the production of this critical chemical intermediate, if appropriate catalysts can be discovered. Recently, heterogeneous catalysts based on boron (oxides and nitrides) have been demonstrated to be promising for ODHP, but their active sites have not been conclusively identified. Here, we report that the deposition of differently sized boronic acids into the micropores of silica supports results in different distributions of surface borate species after calcination. Furthermore, these materials, in turn, display a wide range of rates in ODHP but similar selectivity, suggesting that they differ only in the numbers of active sites. Features identified by in situ Raman, IR, and magic-angle-spinning 11 B solid-state NMR spectroscopies are compared to catalyst activity. This correlation identifies the S2 borate species, a hydroxylated nonring boron, as the likely active site and provides a target for directed syntheses of future catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Multi-mechanistic Strategies for Novel Solid Electrolytes with Superior Properties

Despite a wide range of solid electrolyte phases, most of them only exist at high temperatures. The challenge is to tailor the chemical compositions of solid electrolyte materials that yield high ionic conductivities and low activation energies at ambient temperature. This is crucial for the development of all-solid-state batteries that are both powerful and safe. Here, we report our recent works to meet this challenge by utilizing multiple mechanistic principles and clusters as the building blocks. We show that the atomic-level interactions that govern the fast-ion conduction can be optimized by incorporating polyanion dynamics, non-stoichiometry, point defects and strong ionic correlations. Specifically, two case studies of Li/Na solid electrolytes will be covered, including lithium solid electrolytes (SE) with record-high ionic conductivities at room temperature (over 100 mS/cm) and sodium SE with record-low activation energies (< 0.1 eV).

Fang, Hong↗
DOE OSTI2021

Aerosol Composition, Mixing State, and Phase State of Free Tropospheric Particles and Their Role in Ice Cloud Formation

The prediction of ice cloud formation in the atmosphere remains challenging. Free tropospheric aerosols can act as ice nucleating particles (INPs), affecting cloud properties and precipitation. The physicochemical properties of free tropospheric particles are modified upon long-range transport by different atmospheric processes. These modifications affect the ice formation potential of individual particles. We investigated free tropospheric particles collected at the remote Pico Mountain Observatory at 2225m a.s.l. in the North Atlantic Ocean using multimodal microspectroscopy and chemical imaging techniques. We probed their ice nucleation activity using an ice nucleation stage interfaced with an environmental scanning electron microscope. Retroplume analysis, chemical imaging, and micro-spectroscopy analysis indicated that the size-resolved chemical composition, mixing state, and phase state of the articles with similar aging times but different transport patterns were substantially different. Relative humidity-dependent glass transition temperatures estimated from meteorological conditions were consistent with the observed organic component of the particles' phase. More viscous (solid and semi-solid-like) particles are more ice active in deposition mode at temperature ranging from 205-220 K than those less viscous particles. Finally, this study provides a better understanding of the phase and mixing state of long range transported free tropospheric aerosols and their role in ice cloud formation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Metal infiltrated electrodes for solid state batteries

Disclosed are electrochemical devices and methods for making electrochemical devices such as metal infiltrated electrodes for solid state lithium ion and lithium metal batteries. In one method for forming an electrode, a metal is infiltrated into the pore space of the active material of the electrode providing improved electronic conductivity to the electrode. The electrode may also include a solid-state ion conducting material providing improved ion conductivity to the electrode. Before infiltration of the metal, a stabilization coating may be applied to the active material and/or the solid-state ion conducting material to the stabilize electrode interfaces by slowing, but not eliminating, the chemical reactions that occur at elevated temperatures during sintering of the active material and/or the solid-state ion conducting material forming the electrode.

Sakamoto, Jeffrey↗
DOE OSTI2020

Benefit FOA FY2015 - Solid State Magnetocaloric Air Conditioner (Final Report)

The active magnetic refrigeration (AMR) cycle holds great promise to reduce energy consumption of space cooling and heating. It is estimated that it could achieve up to 25% improvement in energy efficiency over conventional vapor compression systems. Prototypes have been built and demonstrated the working principles and energy benefits of the technology. These prototypes however were of low specific cooling power, defined as cooling power obtainable from unit mass of magnetocaloric materials (MCM). Specific cooling power is inversely proportional to the cost of the system. Therefore, for the magnetocaloric technology to be commercially viable, the specific cooling power must be increased. To increase the specific cooling power, for any MCM, the frequency of operation must increase. However, the maximum frequency that an AMR can operate at is limited by the residence time that is required to transfer heat in and out of the regenerator during the cold and got blows. This time length is dependent on the thermal conductivity of the heat transfer medium. The higher the thermal conductivity of the heat transfer medium, the faster heat can be transferred between the medium and the MCM.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Systems and methods for dynamically reconfigurable artificial synapses and neurons with tunable activation functions

An ionic redox transistor comprises a solid channel, a solid reservoir layer, and a solid electrolyte layer disposed between the channel and the reservoir layer. The channel exhibits a substantially linear current-voltage relationship in a first range of voltages, and a nonlinear current-voltage relationship in a second range of voltages that is greater than the first range of voltages. One or both of the substantially linear current-voltage relationship or the nonlinear current-voltage relationship of the channel is varied by changing the concentration of ions such as oxygen vacancies in the channel. Ion or vacancy transport between the channel and the reservoir layer across the electrolyte layer occurs in response to applying a voltage between the channel and the reservoir layer. Subject to the first range of voltages, the channel can function as a synapse device. Subject to the second range of voltages, the channel can function as a neuron device.

Talin, Albert Alec↗
DOE OSTI2026

Disentangling interlayer confinement and pore surface adsorption in functionalized smectites for tunable ethylene gas capture

Smectite-based adsorbents are increasingly being studied as sustainable packaging materials for scavenging ethylene, a plant hormone that accelerates fruit ripening. However, the mechanisms governing their uptake and retention remain poorly understood. Here, to tackle this question we systematically investigate ethylene gas-solid interactions in pristine, acid-activated, and choline-functionalized montmorillonites using a complementary combination of structural, gravimetric, and spectroscopic techniques, including inelastic neutron scattering. We experimentally distinguish ethylene populations associated with interlayer confinement, mesopore, and external surface adsorption. We show that chemical functionalization distinctly controls adsorption pathways: acid activation enhances total uptake by generating mesoporous adsorption sites and promoting partial interlayer intercalation, yielding capacities comparable to those of leading smectite-based adsorbents, while choline functionalization promotes preferential confinement and stabilization of guest molecules within the interlayer galleries. Advanced spectroscopic analysis provides molecular-level insight into confinement environments and interaction strengths. We also establish clear structure-property relationships by correlating uptake values derived from independent techniques, linking chemical modification, accessible adsorption domains, and retention behavior. These findings provide general design principles for tuning gas-solid interactions in functionalized layered silicates and highlight their potential as adaptable platforms for sustainable ethylene gas capture and selective adsorption technologies.

Ethylene adsorption mechanism↗
DOE OSTI2022

Evaluation of Sludge Solids Returns Impacts on Sludge Batch 10 Flammability, Glass Quality, and Glass Processability

The Savannah River National Laboratory (SRNL) is currently preparing to return ≤ 20 kgs of sludge solids collected over time from Tank Farm characterization activities and demonstrations of the Defense Waste Processing Facility (DWPF) flowsheets (nitric-formic and nitric-glycolic). These sludge solids will be transported and added to Tank 51 which is currently preparing Sludge Batch (SB) 10. DWPF plans to operate the under the nitric-glycolic flowsheet for the processing of SB10. The hydrogen generation rate for the nitric-glycolic flowsheet is 0.024 lb h -1 . The addition of ≤20 kg of sludge solids returns to SB 10 does not have an impact on flammability in the DWPF Chemical Process Cell (CPC) or glass quality and processability. The relatively low mass of the addition (≤20 kg) is insufficient to detect a significant analytical change to the expected SB 10 compositions.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Activation of Low-Valent, Multiply M–M Bonded Group VI Dimers toward Catalytic Olefin Metathesis via Surface Organometallic Chemistry

Olefin metathesis is a broadly employed reaction with applications that range from fine chemicals to materials and petrochemicals. The design and investigation of olefin metathesis catalysts have been ongoing for over half a century, with advancements made in terms of activity, stability, and selectivity. Immobilization of organometallic complexes onto solid supports such as silica or alumina is a promising strategy for catalyst heterogenization, often resulting in increased activity and stability. Consequently, a broad range of early transition metal catalysts bearing alkyl, oxide/alkoxide, and amide ligands have been grafted onto silica and their reactivities investigated. In this paper, we report a series of silica-supported tungsten and molybdenum dimers (X 3 M≡MX 3, where M = W and Mo; X = neopentyl, tert-butoxide, and dimethyl amide) and their reactivities toward catalytic olefin metathesis. Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR), diffuse reflectance infrared Fourier transform (DRIFT), UV resonance Raman, and X-ray absorption (XAS) spectroscopies suggest that upon heterogenization the dimers bind to the surface in a monopodal fashion, with the M≡M triple bond remaining intact. These structural assignments were further corroborated by density functional theory (DFT) calculations. While the homogeneous dimer counterparts are inert, the supported low-valent alkyl W and Mo dimers become active for the disproportionative self-metathesis of propylene to ethylene and butenes and 4-nonene to 4-octene and 5-decene under mild conditions. The lack of activity observed for the free and supported tert-butoxide and dimethyl amide dimers likely suggests that the neopentyl groups are necessary for the formation of a putative alkylidene active species. The difference in reactivity between the free and supported dimers could be explained either by the lowering of the activation barrier of the complex through the electronic effects of the surface or by site isolation of catalytically relevant reactive intermediates.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Atomically Dispersed Copper Sites in a Metal–Organic Framework for Reduction of Nitrogen Dioxide

Metal-organic framework (MOF) materials provide an excellent platform to fabricate single-atom catalysts due to their structural diversity, intrinsic porosity, and designable functionality. However, the unambiguous identification of atomically dispersed metal sites and the elucidation of their role in catalysis are challenging due to limited methods of characterization and lack of direct structural information. Here, we report a comprehensive investigation of the structure and the role of atomically dispersed copper sites in UiO-66 for the catalytic reduction of NO 2 at ambient temperature. The atomic dispersion of copper sites on UiO-66 is confirmed by high-angle annular dark-field scanning transmission electron microscopy, electron paramagnetic resonance spectroscopy, and inelastic neutron scattering, and their location is identified by neutron powder diffraction and solid-state nuclear magnetic resonance spectroscopy. The Cu/UiO-66 catalyst exhibits superior catalytic performance for the reduction of NO 2 at 25 °C without the use of reductants. A selectivity of 88% for the formation of N2 at a 97% conversion of NO 2 with a lifetime of >50 h and an unprecedented turnover frequency of 6.1 h-1 is achieved under nonthermal plasma activation. In situ and operando infrared, solid-state NMR, and EPR spectroscopy reveal the critical role of copper sites in the adsorption and activation of NO 2 molecules, with the formation of {Cu(I)···NO} and {Cu···NO 2 } adducts promoting the conversion of NO 2 to N 2 . This study will inspire the further design and study of new efficient single-atom catalysts for NO 2 abatement via detailed unravelling of their role in catalysis.

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

Insights into the Structure–Activity Relationships in Metal–Organic Framework-Supported Nickel Catalysts for Ethylene Hydrogenation

Solid supports play an indispensable role in heterogeneous catalysis, as they can directly affect the catalytic activity and selectivity of supported catalysts. However, the specific roles of such supports remain to be demystified owing to the difficulties in obtaining precise structural information on supported catalysts. To understand the effects of MOF topology, pore environment, and metal identity of node supports on the catalytic activity, a Ni catalyst was supported on eight Zr- or Hf-MOFs based on 8-connected nodes: namely M-NU-1200, M-NU-1000, M-NU-1008, and M-NU-1010 (M = Zr, Hf). Single-crystal X-ray diffraction (SCXRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS) were employed to characterize the supported catalyst structures. To investigate the support effects on their activities, the supported Ni catalysts were evaluated by using ethylene hydrogenation as a model reaction. The results revealed that all Hf-based-MOF-supported Ni catalysts exhibited higher catalytic reactivity with TOF (turnover frequency) values at least double of those isostructural Zr counterparts. Additionally, MOFs with less congested metal anchoring sites, as a result of the topology and surrounding pore environment, yielded higher TOFs, suggesting the importance of supports in dictating both the catalyst accessibility and activity. Computational analysis complemented the experimental observations and provided insights into reaction barrier differences and their performance variation. Furthermore, this study demonstrates the essential role of the supports and provides a thought for selecting/designing suitable supports in heterogeneous catalysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Semi-solid electrodes having high rate capability

Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode and a semi-solid cathode. The semi-solid cathode includes a suspension of an active material of about 35% to about 75% by volume of an active material and about 0.5% to about 8% by volume of a conductive material in a non-aqueous liquid electrolyte. An ion-permeable membrane is disposed between the anode and the semi-solid cathode. The semi-solid cathode has a thickness of about 250 μm to about 2,000 μm, and the electrochemical cell has an area specific capacity of at least about 7 mAh/cm2 at a C-rate of C/4. In some embodiments, the semi-solid cathode slurry has a mixing index of at least about 0.9.

Chiang, Yet-Ming↗
DOE OSTI2023

Semi-solid electrodes having high rate capability

Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cells includes an anode and a semi-solid cathode. The semi-solid cathode includes a suspension of an active material of about 35% to about 75% by volume of an active material and about 0.5% to about 8% by volume of a conductive material in a non-aqueous liquid electrolyte. An ion-permeable membrane is disposed between the anode and the semi-solid cathode. The semi-solid cathode has a thickness of about 250 μm to about 2,000 μm, and the electrochemical cell has an area specific capacity of at least about 7 mAh/cm 2 at a C-rate of C/4. In some embodiments, the semi-solid cathode slurry has a mixing index of at least about 0.9.

Chiang, Yet-Ming↗
DOE OSTI2026

Thermal Decomposition Kinetics of 4,6‐Diamino‐5,7‐dinitro‐benzo‐furazan

This experimental study investigated the thermal decomposition kinetics of 4,6-diamino-5,7-dinitro-benzo-furazan (referred to as F1 hereafter)—an important decomposition product of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB—a prototypical insensitive high explosive). Simultaneous differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and mass spectrometry (MS) measurements were employed to determine the decomposition kinetics of F1 and to track the evolution of product gases. The DSC profiles were measured at 10 different heating rates between 0.025°C/min and 10°C/min. The measured exotherms were influenced by F1 melting at heating rates above 0.25°C/min, and corresponding changes in decomposition enthalpy and TGA mass-loss-rate profiles indicated a transition from solid-to-gas decomposition to an increasing contribution from liquid-to-gas decomposition. Analysis of low-heating-rate DSC data between 0.025°C/min and 0.17°C/min with the extended Prout–Tompkins model yielded an activation energy of 305 kJ/mol for solid-to-gas F1 decomposition, higher than previous values inferred from TATB decomposition models involving F1. This study provides the first direct experimental determination of the energy barrier for F1 decomposition. MS measurements showed that the major gaseous products matched species previously reported for TATB decomposition (e.g., CO 2 , HCN, C 2 N 2 , etc.), with water identified as the dominant product. Furthermore, these results provide important experimental constraints for improving chemical kinetics models of TATB decomposition and for predicting the reactivity, stability, and safety of TATB-based high explosives under long-term aging conditions and abnormal thermal environments.

4,6-Diamino-5,7-dinitro-benzo-furazan↗
DOE OSTI2022

Analysis in Support of Disposition of Tank 48 Legacy Material

This report contains the characterization of six 200-mL Tank 48H samples: HTF-48-21-74, HTF-48-21-75, HTF-48-21-76, HTF-48-21-81, HTF-48-21-82, and HTF-48-21-83. The effort supports a Systems Engineering Evaluation (SEE) recommendation involving a Tank 48H decantation strategy that would remove liquid volume and grout the solids. The first three Tank 48H samples were surface samples taken after a quiescent period in the tank. The quiescent period allowed settling of the solids, these being mostly potassium tetraphenylborate. These three surface samples had no measurable solids, though a settling haze could be seen. The latter three samples were taken at 48, 25, and 10 inches from the bottom of Tank 48H immediately after tank mixing pumps had been run. Those samples contained measurable insoluble solids that were readily visible. All six samples were analyzed to provide chemical and radionuclide concentrations as defined as the "Limit" and "Target" in the Saltstone Production Facility (SPF) Waste Acceptance Criteria (WAC) and per the compliance strategy in the Tank Farm Waste Compliance Plan (WCP). Samples were analyzed by many methods to determine pH, density/specific gravity, radioactive isotopes, soluble and insoluble elements, total solids, total insoluble solids, organic and inorganic mercury, volatile and semi-volatile chemicals, and anions. Photographs of the settling of small samples were taken over time and are displayed in this report. The extent of settling was very significant, showing that surface sample liquids are similar to filtrates. However, Cs-137 measurements exceeded WAC limits in all surface samples (1.1E+07 vs. 1.3E+06). The solids were found to contain very high cesium activity, measured as high as 1.1E+10 dpm/gram. Sodium was in the range of 4.24 to 4.74 M for all samples, so the solids would tend to settle with time and would not be at risk of floating without air entrainment. No organic mercury was detected in this work.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Analysis in Support of Disposition of Tank 48 Legacy Material

This report contains the characterization of six 200-mL Tank 48H samples: HTF-48-21-74, HTF-48-21-75, HTF-48-21-76, HTF-48-21-81, HTF-48-21-82, and HTF-48-21-83. The effort supports a Systems Engineering Evaluation (SEE) recommendation involving a Tank 48H decantation strategy that would remove liquid volume and grout the solids. The first three Tank 48H samples were surface samples taken after a quiescent period in the tank. The quiescent period allowed settling of the solids, these being mostly potassium tetraphenylborate. These three surface samples had no measurable solids, though a settling haze could be seen. The latter three samples were taken at 48, 25, and 10 inches from the bottom of Tank 48H immediately after tank mixing pumps had been run. Those samples contained measurable insoluble solids that were readily visible. All six samples were analyzed to provide chemical and radionuclide concentrations as defined as the "Limit" and "Target" in the Saltstone Production Facility (SPF) Waste Acceptance Criteria (WAC) and per the compliance strategy in the Tank Farm Waste Compliance Plan (WCP). Samples were analyzed by many methods to determine pH, density/specific gravity, radioactive isotopes, soluble and insoluble elements, total solids, total insoluble solids, organic and inorganic mercury, volatile and semi-volatile chemicals, and anions. Photographs of the settling of small samples were taken over time and are displayed in this report. The extent of settling was very significant, showing that surface sample liquids are similar to filtrates. However, Cs-137 measurements exceeded WAC limits in all surface samples (1.1E+07 vs. 1.3E+06). The solids were found to contain very high cesium activity, measured as high as 1.1E+10 dpm/gram. Sodium was in the range of 4.24 to 4.74 M for all samples, so the solids would tend to settle with time and would not be at risk of floating without air entrainment. No organic mercury was detected in this work.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗