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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Sulfur Polymers as Flexible Interfacial Additives for Low Stack-Pressure Solid-State Lithium-Ion Batteries

Solid-state batteries (SSBs) fabricated using sulfide solid electrolytes (SSEs) typically require cell stack-pressures in the range of tens to hundreds of megapascals to maintain effective interfacial contact and lithium-ion mobility across the full cell stack. These relatively high cell stack-pressures necessarily require additional cell components that reduce the delivered volumetric and gravimetric capacities of SSBs. This work has developed a novel sulfur polymer (polyS) that improves lithium-ion conductivity in SSBs at low cell stack-pressures, thereby directly targeting this technological limitation. Specifically, this work shows that polyS can be combined with the argyrodite Li6PS5Cl (LPSC) to form a stable composite SSE. By combining LPSC particles with a flexible additive that enhances interfacial contact at low pressures, this new polyS LPSC composite SSE material greatly improves ionic conductivity at cell stack-pressures below 2.0 MPa in comparison to conventional LPSC composites. Furthermore, this polyS LPSC composite can be used to fabricate a full SSB that cycles reversibly at only 1.6 MPa. Finally, this composite SSE exhibits self-healing behavior when combined with a lithium metal electrode, wherein lithium dendrites are oxidized to form passivating Li2S species that recover the cell from shorting.

ENERGY STORAGE↗
DOE OSTI2023

Breaking Rayleigh’s Law with Spatially Correlated Disorder to Control Phonon Transport

Controlling thermal transport in insulators and semiconductors is crucial for many technological fields such as thermoelectrics and thermal insulation, for which a low thermal conductivity (κ) is desirable. A major obstacle for realizing low κ materials is Rayleigh’s law, which implies that acoustic phonons, which carry most of the heat, are insensitive to scattering by point defects at low energy. We demonstrate, with large scale simulations on tens of millions of atoms, that isotropic long-range spatial correlations in the defect distribution can dramatically reduce phonon lifetimes of important low-frequency heat-carrying modes, leading to a large reduction of κ—potentially an order of magnitude at room temperature. We propose a general and quantitative framework for controlling thermal transport in complex functional materials through structural spatial correlations, and we establish the optimal functional form of spatial correlations that minimize κ. Finally, we end by briefly discussing experimental realizations of various correlated structures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Realizing high-capacity all-solid-state lithium-sulfur batteries using a low-density inorganic solid-state electrolyte

Abstract Lithium-sulfur all-solid-state batteries using inorganic solid-state electrolytes are considered promising electrochemical energy storage technologies. However, developing positive electrodes with high sulfur content, adequate sulfur utilization, and high mass loading is challenging. Here, to address these concerns, we propose using a liquid-phase-synthesized Li 3 PS 4 -2LiBH 4 glass-ceramic solid electrolyte with a low density (1.491 g cm −3 ), small primary particle size (~500 nm) and bulk ionic conductivity of 6.0 mS cm −1 at 25 °C for fabricating lithium-sulfur all-solid-state batteries. When tested in a Swagelok cell configuration with a Li-In negative electrode and a 60 wt% S positive electrode applying an average stack pressure of ~55 MPa, the all-solid-state battery delivered a high discharge capacity of about 1144.6 mAh g −1 at 167.5 mA g −1 and 60 °C. We further demonstrate that the use of the low-density solid electrolyte increases the electrolyte volume ratio in the cathode, reduces inactive bulky sulfur, and improves the content uniformity of the sulfur-based positive electrode, thus providing sufficient ion conduction pathways for battery performance improvement.

25 ENERGY STORAGE↗
DOE OSTI2021

New Noncentrosymmetric Tetrel Pnictides Composed of Square‐Planar Gold(I) with Peculiar Bonding

Abstract Three novel isostructural equiatomic gold tetrel pnictides, AuSiAs, AuGeP, and AuGeAs, were synthesized and characterized. These phases crystallize in the noncentrosymmetric (NCS) monoclinic space group Cc (no. 9), featuring square‐planar Au within cis ‐[AuTt 2 Pn 2 ] units (Tt=tetrel, Si, Ge; Pn=pnictogen, P, As). This is in drastic contrast to the structure of previously reported AuSiP, which exhibits typical linear coordination of Au with Si and P. Chemical bonding analysis through the electron localization function suggests covalent two‐center two‐electron Tt−Pn bonds, and three‐center Au−Tt−Au and Au−Pn−Au bonds with 1.6 e − per bond. X‐ray photoelectron spectroscopy studies support the covalent and nonionic nature of Au−Pn and Au−Tt bonds. The title materials were found to be n ‐type narrow‐gap semiconductors or semimetals, with nearly temperature‐independent electrical resistivities and low thermal conductivities. A combination of the semimetallic properties with tunable NCS structure provides opportunities for the development of materials based on gold tetrel pnictides.

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

Thermal analysis of RHIC arc dipole magnet cold mass with EIC beam screen

The existing RHIC storage rings – including their superconducting magnet arcs – will be used for the hadron storage ring of the Electron-Ion Collider (EIC). The vacuum chamber of these magnets was not designed for the EIC hadron beams, with shorter bunches and of higher average current than the RHIC beams. With the current stainless steel beam pipe, the resistive-wall (RW) heating will exceed the dynamic heat load budget. Limiting the RW heating is important to prevent the superconducting magnets from quenching and to maintain a low screen temperature necessary to impede the rise of RW heating (higher resistance at higher temperature) as well as to achieve desired ultra-high vacuum. In addition, simulations predict the formation of electron cloud which would further contribute to the dynamic heat load and could compromise the quality and stability of the beam. To reduce the resistive-wall heating and suppress electron cloud, a beam screen will be installed in the vacuum chamber of the RHIC SC magnets. The screen will have a high RRR copper layer at its inner face – useful to reduce the resistive-wall impedance thanks to its high conductivity especially at cryogenic temperatures – and will be coated with a thin layer of amorphous carbon, a material with low secondary electron yield to suppress the formation of electron clouds. The baseline solution envisages a screen that will be cooled by thermal contact to the 4.55 K beam pipe. Detailed thermal analysis have been conducted in ANSYS 2020 for an arc dipole cold mass equipped with a beam screen in order to study the feasibility of a passively-cooled screen and guide its design. Temperature-dependent thermal conductivity properties of all materials in the operating (cryogenic) temperature range are considered. Suitable assumptions and simplifications are made to model the magnet coil and calculate its homogenized thermal conductivity. Sensitivity studies with respect to layer thicknesses and area of contact are carried out and results are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Large magnon-induced anomalous Nernst conductivity in single-crystal MnBi

Thermoelectric modules are a promising approach to energy harvesting and efficient cooling. In addition to the longitudinal Seebeck effect, transverse devices utilizing the anomalous Nernst effect (ANE) have recently attracted interest. For high conversion efficiency, it is required that the material have a large ANE thermoelectric power and low electrical resistance, which lead to the conductivity of the ANE. ANE is usually explained in terms of intrinsic contributions from Berry curvature. Our observations suggest that extrinsic contributions also matter. Studying single-crystal manganese-bismuth (MnBi), we find a high ANE thermopower (~10 μV/K) under 0.6 T at 80 K, and a transverse thermoelectric conductivity of over 40 A/Km. With insight from theoretical calculations, we attribute this large ANE predominantly to a new advective magnon contribution arising from magnon-electron spin-angular momentum transfer. We propose that introducing a large spin-orbit coupling into ferromagnetic materials may enhance the ANE through the extrinsic contribution of magnons.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Progress Towards the Reality of Low-Temperature Critical Experiments with Low-Temperature TEX

Integral benchmarks for criticality safety do not exist below room temperature. Incredible support for below room temperature benchmarks is present across the international community. Validation of low-temperature neutron cross sections is necessary to verify any operation at temperatures below room temperature which is typically observed in environments far from the equator. For example, a fissile material transportation truck may routinely observe ambient temperatures down to -40°C, which is the lower temperature bound of the normal conditions of transportation defined in the United States Title 10 Code of Federal Regulations §71.71c2. Similarly, the IAEA, which contains 176 member states, has the same requirement for subcriticality for fissile material transportation. Additionally, sub-room temperature benchmarks can validate newly produced cross sections, that include novel thermal scattering laws, from North Carolina State University. A six-case experiment designed based off the TEX-HEU baseline experiments has been proposed utilizing a chilled vacuum chamber capable of cooling the HEU stack down to -50°C. The six proposed configurations span the entire neutron fission energy range and can be tested at intermediate temperatures between room temperature and -40°C. Of the six configurations, the fastest case utilizes nearly 135 kg of HEU. Understanding the system is required prior to critical experiment operations. In order to test the functionality of the system, testing with surrogate fuel materials has been conducted. The following discusses the design of the low temperature TEX (LT-TEX) experiment as well as the progress made via surrogate testing towards a reality in which low-temperature integral benchmarks exist in the International Criticality Safety Benchmark Evaluation Project (ICSBEP).

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Liquid Metals for Advanced Batteries: Recent Progress and Future Perspective

ABSTRACT The shift toward sustainable energy has increased the demand for efficient energy storage systems to complement renewable sources like solar and wind. While lithium‐ion batteries dominate the market, challenges such as safety concerns and limited energy density drive the search for new solutions. Liquid metals (LMs) have emerged as promising materials for advanced batteries due to their unique properties, including low melting points, high electrical conductivity, tunable surface tension, and strong alloying tendency. Enabled by the unique properties of LMs, four key scientific functions of LMs in batteries are highlighted: active materials, self‐healing, interface stabilization, and conductivity enhancement. These applications can improve battery performance, safety, and lifespan. This review also discusses current challenges and future opportunities for using LMs in next‐generation energy storage systems. image

Zheng, Tianrui [Materials Science and Engineering ↗
DOE OSTI2022

Ultra-rapid, physics-based development pathway for reactor-relevant RF antenna materials

This paper presents a rapid, atomistically-informed, experimental development pathway for fusion reactor-relevant radio frequency (RF) antenna materials in the Cu-Cr-(Nb,Al,Zr) composition system, with the goal of improving upon GRCop-84. RF antennas in a tokamak fusion reactor will face a unique set of challenges as both structural and functional materials. The desired material must simultaneously achieve and maintain high electrical conductivity, high strength, high thermal conductivity, resist high temperatures, possess low nuclear activation, and incur low damage due to neutron bombardment. The GRCop-84 alloy serves as a starting point for iterative improvement, with the desire to reduce or eliminate Nb from the material to minimize nuclear activation. The rapid development pathway makes use of a multi-target combinatorial thick film sputtering process to produce full ternary phase diagrams on a Si wafer substrate. Transient grating spectroscopy (TGS), a laser-ultrasonic method, will determine spatially-varying thermo-elastic properties, while four terminal electrical conductivity measurements will map out the best per- forming regions of the sample for in-depth study at larger length scales. High energy proton and self-ion irradiation emulates the effects of neutron damage on the thermal/electric properties. With rapid turnaround time (∼days) in terms of mapping radiation damage-induced material property changes in the full ternary system, these techniques allow rapid iteration towards an optimal material, testing hundreds of nearby compositions in the time it took to test one. Focused testing of larger, single composition samples (produced in an arc furnace or by laser sintering) provides data on structural and high power RF properties, and validates our thick-film based workflow.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Interfacial thermal conductance between multi-layer graphene sheets and solid/liquid octadecane: A molecular dynamics study

Mixtures of paraffin and carbon nanofillers have promising potential for thermal storage, as paraffin (the matrix) possesses high latent heat and the nanofillers compensate for the low thermal conductivity (TC) of paraffin. Understanding thermal transport in these materials is essential for practical applications, as weak thermal transport hinders fast charge/discharge of thermal energy. Here, we use non-equilibrium molecular dynamics (NEMD) simulations to study the interfacial thermal conductance (ITC) between graphene sheets and octadecane (C18H38) matrix under the limiting conditions of the sheets being parallel or perpendicular to the direction of the imposed heat flux. The findings show that the systems containing thin graphene layers exhibit higher values of ITC. This study captures the asymptotic saturation of thermal conductance for the liquid phase of the perpendicular structure. Besides, given the greater number of structured layers of paraffin upon phase change, the ITC for the solid paraffin-graphene system is higher than the conductance of the liquid paraffin-graphene interface. We use the Pearson correlation coefficients of the vibrational power spectrum (VPS) of interfacing materials to explain the orders of magnitude variations of the observed ITC.

25 ENERGY STORAGE↗
DOE OSTI2023

Ferroelectric control of magnetic anisotropy of 5 d transition metal monolayers

Electric field control of magnetism using ferroelectric materials offers promising applications in low-power spintronics. We have conducted systematic density functional theory calculations to investigate the magnetic properties of epitaxial 5 d transition metal monolayers on a ferroelectric substrate: PbTi⁢O 3 (PTO). Our study reveals that the magnetocrystalline anisotropy energy of the osmium monolayer is significantly enhanced to 18.1 meV/Os in the upward polarization state and, moreover, the anomalous Hall coefficient of osmium/PTO film is tunable by reversing the electric polarization of the PTO substrate. Additionally, the electric polarization reversal in PTO rotates the easy magnetization axis of the iridium and platinum monolayers by 90°, which is attributed to the rearrangement of interfacial charges. In conclusion, our findings suggest an efficient approach to control the magnetization direction of monoatomic layers and provide valuable insights for the development of low-energy spintronics devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Nondestructive Evaluation (NDE) of Cable Moisture Exposure using Frequency Domain Reflectometry (FDR)

This Pacific Northwest National Laboratory (PNNL) milestone report assesses the capability of frequency domain reflectometry (FDR) to determine electrical cable submergence using PNNL’s Accelerated and Real-Time Environmental Nodal Assessment (ARENA) cable/motor test bed. This work includes a review of relevant literature as well as experimental tests. Nuclear power facilities have experienced various electrical cable failures related to water exposure. The current industry response involves actions to de-water cable vaults, manholes, and other cable locations. These efforts require considerable expenditure of resources, which makes it desirable for the industry to have information on cable condition and history regarding their submergence and water exposure (Mantey 2012). Two tests that are gaining favor within the nuclear industry are time-domain reflectometry (TDR) and FDR. These are low-voltage nondestructive tests that can be applied at a cable end. Testing from the cable end is important because local inspection along the cable length is very difficult due to cables being routed within trays, conduits, underground, and through walls. Both TDR and FDR techniques have been shown to locate cable insulation damage due to thermal, radiation, and mechanical damage. FDR measurements are also more sensitive than TDR to temperature changes, low-bend radius bends, and cable contact with various materials, including conductive materials like steel and water. This work evaluates the feasibility to extend FDR testing to characterizing whether an electrical cable is submerged or not and where it may be submerged using PNNL’s ARENA cable/motor test bed.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2021

CFA-17-12798: Nanostructured Ceramic Membranes for Enhanced Tritium Management

This project focuses on the novel use of interfacial hydrated layers in ionic conducting ceramic materials for tritiated water (HTO) adsorption and recovery. Low-temperature water adsorption properties of nanoscale structured ceramics combined with hydrogen isotope exchange in their hydrated layers could provide a low-cost and transformative avenue to address tritium management challenges.

08 HYDROGEN↗
DOE OSTI2025

Metal Complex Inks for Low-Cost Photovoltaic Material Metallization

The aim of the project titled “Metal Complex Inks for Low-Cost Photovoltaic Material Metallization” was to develop new metal complex conductive inks and pastes for PV, invented and commercialized by Electroninks, Inc. (EI, Austin, TX USA, https://electroninks.com), the only global supplier and scaled-manufacturing company of these metal complex inks. These materials were developed in this work for photovoltaic applications to significantly lower the cost of metallization, improve the manufacturability, and greatly reduce metal usage, while maintaining or improving device efficiencies when compared to traditional nanoparticle-based inks. The new pastes will do so by: 1) lowering the finger resistivity and precious metals usage by printing much denser (and therefore thinner/less material) metal films than possible with traditional particle-based screen-printed pastes; 2) decreasing the firing temperature to help preserve passivation; and 3) enabling a path to move the TW-scale PV industry from Ag to other materials including Ni, Cu, and Ni/Cu alloy pastes while continuing to leverage capital investment and expertise in screen printing metallization.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Microstructure and 77K mechanical properties of electron beam welded Cu101- Inconel 625 joints

In developing large-scale next-generation superconducting radio frequency (SRF) linear accelerators using superconducting films on Cu, the design and development of dissimilar welding and joining metals, such as Cu to Inconel, stainless steel, and Nb, are essential. In this talk, we present the development of procedures for electron-beam welding of Cu¿Inconel 625 and evaluation of the microstructure and 77K mechanical properties of the weld and base material in the welded condition and heat treatments in the 750°C ¿950°C heat treatment range. The results will be presented in the context of developing joining techniques for low-temperature applications where high conductivity and strength, vacuum hygiene, and magnetic properties of the material need consideration. The methods presented here are being deployed to thin film SRF Cu cavities at Jefferson Lab. Acknowledgment: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear

Khanal, Bashu↗
DOE OSTI2025

Nodal hybridization in a two-dimensional heavy-fermion material

Metals with partially filled core atomic shells can form quasiparticles at a low temperature arising from the hybridization of the core level and conduction electrons. The thermodynamic and spectroscopic properties of these metals can be understood as those of a simple metal, but with a significant mass enhancement over the free electron mass—commonly referred to as heavy fermions. In most heavy-fermion materials, the hybridization is approximately isotropic in position and momentum space. However, a combination of low dimensionality and symmetry properties of the core-level wavefunctions can give rise to highly anisotropic electronic interactions with the conduction electrons. Here, in this study, we demonstrate anisotropic hybridization that vanishes along specific directions in momentum space—referred to as nodes—in a lanthanide-based two-dimensional van der Waals heavy-fermion compound, CeSiI. Quasiparticle interference measurements reveal a set of discrete hotspots with high spectral intensity on the Fermi surface. Theoretical modelling and comparison with the quasiparticle interference pattern of the non-heavy-fermion isostructural analogue LaSiI suggest that these features arise from an unconventional electron interaction involving hybridization nodes unique to CeSiI. As a result, the effective mass of the quasiparticles varies by orders of magnitude depending on their direction in momentum space.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Depth-dependent recovery of thermal conductivity after recrystallization of amorphous silicon

The depth-dependent recovery of silicon thermal conductivity was achieved after the recrystallization of silicon that had been partially amorphized due to ion implantation. Transmission electron microscopy revealed nanoscale amorphous pockets throughout a structurally distorted band of crystalline material. The minimum thermal conductivity of as-implanted composite material was 2.46 W m −1 K −1 and was found to be uniform through the partially amorphized region. X-ray diffraction measurements reveal 60% strain recovery of the crystalline regions after annealing at 450 °C for 30 min and almost full strain recovery and complete recrystallization after annealing at 700 °C for 30 min. In addition to strain recovery, the amorphous band thickness reduced from 240 to 180 nm after the 450 °C step with nanoscale recrystallization within the amorphous band. A novel depth-dependent thermal conductivity measurement technique correlated thermal conductivity with the structural changes, where, upon annealing, the low thermal conductivity region decreases with the distorted layer thickness reduction and the transformed material shows bulk-like thermal conductivity. Full recovery of bulk-like thermal conductivity in silicon was achieved after annealing at 700 °C for 30 min. After the 700 °C anneal, extended defects remain at the implant projected range, but not elsewhere in the layer. Previous results showed that high point-defect density led to reduced thermal conductivity, but here, we show that point defects can either reform into the lattice or evolve into extended defects, such as dislocation loops, and these very localized, low-density defects do not have a significant deleterious impact on thermal conductivity in silicon.

Huynh, Kenny↗