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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 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Wave properties near the subsolar magnetopause - Pc 1 waves in the sheath transition layer

We study the waves in the frequency range of Pc 1 in the sheath transition layer of the magnetopause from the ISEE 1 and 2 observations. The waves are enhanced in the sheath transition layer, although they are scattered into the magnetosheath when the outer edge of the sheath transition layer is not sharp. The wave frequency is proportional to, and equal to, about 44 percent of the ion gyrofrequency. The waves are left-handed polarized for southward IMF, but linearly polarized for northward IMF. The direction of maximum variation is perpendicular to both the background field and the gradients of the field and density for northward IMF; for southward IMF, the waves are more turbulent. Wave generation mechanisms may depend on IMF orientations rather than the shock geometry. To investigate the free energy generating the waves for northward IMF, a method is developed combining the measurements from the fast plasma experiment and Lepedea to obtain a high time resolution estimate of the temperature anisotropy for strongly northward IMF. The estimated ion temperature anisotropy is enhanced, up to a factor of 2, within the sheath transition layer for northward IMF.

Song, P.↗
DOE OSTI2021

Fast and Scalable Synthesis of LiNi 0.5 Mn 1.5 O 4 Cathode by Sol–Gel-Assisted Microwave Sintering

High-voltage spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) is a promising cathode material for high-energy-density and high-power-density lithium-ion batteries (LIBs). The high cost of the currently available LIBs needs to be addressed urgently for wide application in the transport sector (electric vehicles, buses) and large-scale energy storage systems (ESS). Of significance, herein, novel fast and scalable microwave-assisted synthesis of LNMO is reported, which leads to a production cost cut. X-ray diffraction (XRD) analysis confirms the formation of the desired phase with high crystallinity. Field emission scanning (FE-SEM) and transmission electron microscopy (TEM) analyses indicate that the synthesized phase is of nanometric size (50–150 nm) due to an extremely short sintering time (20 min). The material synthesized at 750 °C shows a higher initial discharge capacity (130 mA h g -1 ) than that synthesized at 650 °C (115 mA h g -1 ). The materials heat treated at higher temperatures show better electrochemical performance in terms of initial capacity, rate capability, and improved cycling. The improved electrochemical performance of LNMO at 750 °C is attributed to the formation of a stable crystal structure, low charge transfer resistance at the electrode/electrolyte interface, high electrical conductivity due to the presence of a disorder structure, and improved ionic diffusivity.

25 ENERGY STORAGE↗
DOE OSTI2021

Fast Na diffusion and anharmonic phonon dynamics in superionic Na 3 PS 4

The design of new solid electrolytes (SEs) hinges on identifying and tuning relevant descriptors. Phonons describe the atomic dynamics in crystalline materials and provide a basis to encode possible minimum energy pathways for ion migration, but anharmonic effects can be large in SEs. Identifying and controlling the pertinent phonon modes coupled most strongly with ionic conductivity, and assessing the role of anharmonicity, could therefore pave the way for discovering and designing new SEs via phonon engineering. In this work, we investigate phonons in Na 3 PS 4 and their coupling to fast Na diffusion, using a combination of neutron scattering, ab initio molecular dynamics (AIMD), and extended molecular dynamics based on machine-learned potentials. We identify that anharmonic soft-modes at the Brillouin zone boundary of the anharmonically stabilized cubic phase constitute key phonon modes that control the Na diffusion process in Na 3 PS 4 . We demonstrate how these strongly anharmonic phonon modes enable Na-ions to hop along the minimum energy pathways. Further, the quasi-elastic neutron scattering (QENS) measurements, supplemented with ab initio and machine-learned molecular dynamics simulations, probe the Na diffusivity and diffusion mechanism. These results offer detailed microscopic insights into the dynamic mechanism of fast Na diffusion and provide an avenue to search for further Na solid electrolytes.

42 ENGINEERING↗
NASA NTRS1995

Large-scale variations of solar wind elemental composition and charge states with heliospheric latitude

The Solar Wind Ion Composition Spectrometer (SWICS) onboard Ulysses allows determination of the elemental composition of the solar wind and the charge states of all major solar wind ion species. Ulysses left the ecliptic plane in early 1992, crossed the Sun's south polar region in late 1994 and made a fast approach back towards the ecliptic in the first half of 1995. Data from this period were investigated for long-term variations in the solar wind composition. At midlatitudes Ulysses encountered periodically the fast solar wind stream emerging from the south coronal hole. As a consequence, dramatic variations in the charge-states arise, between high charge-states dominating in the current sheet solar wind and low charge states in the coronal hole stream. However, the initial analysis indicates that from midlatitudes onwards, with Ulysses permanently immersed in the coronal hole stream, the charge state and elemental abundance ratios of the major solar wind ion species stayed essentially constant. This implies that the temperature profile in the coronal hole at solar wind source altitudes exhibit no variation with solar latitude. It confirms that the south coronal hole is essentially unstructured down to scale lengths of several degrees in solar latitude.

Woch, J.↗
DOE OSTI2021

Role of Molecular Architecture on Ion Transport in Ethylene oxide-Based Polymer Electrolytes

This work aims to develop a detailed mechanistic understanding of the role of a graft polymer architecture on lithium ion (Li + ) transport in poly(ethylene oxide)-based polymer electrolytes. Specifically, we compare Li + transport in poly-(ethylene oxide) (PEO) versus poly(oligo oxyethylene methacrylate) (POEM) polymers doped with lithium bis( trifluoromethanesulfonyl) (LiTFSI) salts, using both experimental electrochemical characterization and molecular dynamics (MD) simulations. Furthermore, our results indicate that POEM exhibits a range of relaxation processes that cannot be interpreted solely in terms of glass-transition temperature (T g ) effects. Due to its side-chain architecture, the segmental relaxation of POEM is nonuniform across ether oxygens (EOs) and shows a more pronounced sensitivity to temperature above T g compared to PEO. Moreover, POEM also exhibits a nonuniform Li + coordination behavior, in which Li + is primarily solvated by two different chains in POEM, compared to a single chain in PEO. Li + transport in POEM occurs via two events with distinct characteristic times: a fast intrachain hopping along side chains and a slow interchain hopping between side chains. Taken together, the relaxation processes and ion transport mechanisms identified in POEM provide useful insights into design of more effective solid polymer electrolytes.

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

Research and Development on Advanced Electrochemical Energy Storage Devices Enabling a Spectrum of Electrified Vehicles

The USABC Advanced Battery development plan had the following three focus areas: 1. Existing technology validation, implementation, and cost reduction 2. Identification of the next viable technology with emphasis on the potential to meet USABC cost and energy density goals. 3. Support high-risk, high-reward battery technology R&D The primary aim of this project was focused on the barriers that most impede wider public adoption of electrification in vehicles-cost, energy density, low-temp performance, calendar life, and improvements in abuse tolerance. The specific objectives are as follows: Cost Reduction: drive to significantly reduce battery cost to be in-line with the $\$$100/kWh or less (by the end of calendar year 2020) DOE cost goals. Additionally, goals of $\$$75/KWh were set for 2023 aligned with fast charge and some offset of energy density. Energy Density Increase: focus on improving the cell-level specific energy and energy densities to >350 watt hours per kilogram (Wh/kg) and >750Wh/L. Low Temperature Performance Increase: strive toward developments that improve the discharge power and eliminate or dramatically reduce the life limiting lithium plating associated with regenerative braking at low temperatures, during the program. Calendar Life Increase: drive to achieve a 15-year calendar life. Abuse Tolerance Improvement: strive to develop improvements in Li-ion abuse tolerance and/or development of electrochemical energy storage technologies with inherently better response to abuse circumstances. Emerging Areas: initiate new programs that address emerging technologies that arise during the contract period.

25 ENERGY STORAGE↗
DOE OSTI2022

Li-Ion Battery Electrode Contact Resistance Estimation by Mechanical Peel Test

Li-ion battery electrode electronic properties, including bulk conductivity and contact resistance, are critical parameters affecting cell performance and fast-charge capability. Contact resistance between the coating and current collector is often the largest electronic resistance in an electrode and is affected by chemical, microstructural, and interfacial variations. Direct measurements of contact resistance and bulk conductivity have proven to be challenging. In their absence, a mechanical electrode peel test is often used to compare adhesion and electrical contact resistance. However, using a micro-flexible-surface probe, contact resistance can be directly determined. Here, this work compares contact resistance and mechanical peel strength of multiple commercial-grade HE5050 and NCM523 cathodes and graphite and silicon anodes. It was found that peel strength correlates well with contact resistance in a carefully curated data set (p < 0.05) and in some situations may be a good metric to estimate electrical properties. However, there were distinct outliers in the data set, indicating that peel strength may not accurately reflect electrical properties when there is significant variation in electrode composition. These results illustrate the value of the micro-flexible-surface probe in quantifying contact resistance and bulk conductivity to better understand how battery composition and processing steps affect microstructure and resulting cell performance.

25 ENERGY STORAGE↗
DOE OSTI2024

A high-performance intermediate temperature reversible solid oxide cell with a new barrier layer free oxygen electrode

The best solution to address the critical durability issue of solid oxide electrolytic cells (SOECs) for high-efficiency and high-rate H 2 production is to lower the operating temperature without sacrificing the performance. Developing high performance oxygen electrodes (OEs) is a key to capitalizing this solution. Here, in this paper, we report on a highly active OE for intermediate temperature ZrO 2 -based SOECs without a CeO 2 barrier layer. The new barrier-layer-free (BLF) OE is a composite of two materials, (Bi 0.75 Y 0.25 ) 0.93 Ce 0.07 O 1.5±δ (BYC) that exhibits high oxide-ion conductivity and La 0.8 Sr 0.2 MnO 3 (LSM) that possesses a high electronic conductivity to enable fast oxygen reduction/evolution reactions (ORR/OER). Featuring a microscale porous BYC scaffold decorated with high surface area LSM nanoparticles (NPs), the new BLF-OE exhibited a low area specific resistance (ASR) of 0.10 Ω cm 2 at 650 °C in air. With 50%H 2 -50%H 2 O as a feed to hydrogen electrode (HE) and air to OE, the single cell performance achieved 588 mA cm -2 at 0.80 V in the fuel cell mode and 688 mA cm -2 at 1.30 V in the electrolytic mode at 650 °C. Our in-house testing showed that this level of performance was ~3.5x higher than the cell with the benchmark La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -Ce 0.9 Gd 0.1 O 2-δ OE. The long-term durability testing under alternating fuel cell and electrolytic modes showed a low degradation rate of 0.10 mA cm -2 h -1 over 550 hours. These encouraging results showed the great promise of the newly developed BYC-LSM to be an excellent OE candidate for intermediate temperature SOECs.

25 ENERGY STORAGE↗
DOE OSTI2020

Actinide Separation Inspired by Self-Assembled Metal–Polyphenolic Nanocages

The separation of actinides has a vital place in nuclear fuel reprocessing, recovery of radionuclides, and remediation of environmental contamination. Here we propose a new paradigm of nanocluster-based actinide separation, namely, nanoextraction, that can achieve efficient sequestration of uranium in an unprecedented form of giant coordination nanocages using a cone-shaped macrocyclic pyrogallol[4]arene as the extractant. The U 24 -based hexameric pyrogallol[4]arene nanocages with distinctive [U 2 (PG) 2 ] binuclear units (PG = pyrogallol) that rapidly assembled in situ in monophasic solvent were identified by single-crystal X-ray diffraction, MALDI-TOF mass spectrometry, NMR spectroscopy, and small-angle X-ray and neutron scattering. Furthermore, comprehensive biphasic extraction studies showed that this novel separation strategy has enticing advantages such as fast kinetics, high efficiency, and good selectivity over lanthanides, thereby demonstrating its potential for efficient separation of actinide ions.

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

Liquid-like dynamics in a solid-state lithium electrolyte

Superionic materials represent a regime intermediate between the crystalline and liquid states of matter. Despite the considerable interest in potential applications for solid-state batteries or thermoelectric devices, it remains unclear whether the fast ionic diffusion observed in superionic materials reflects liquid-like dynamics or whether the hops of mobile ions are inherently coupled to more conventional lattice phonons. Here we reveal a crossover from crystalline vibrations to relaxational dynamics of ionic diffusion in the superionic compound Li 6 PS 5 Cl, a candidate solid-state electrolyte. By combining inelastic and quasi-elastic neutron-scattering measurements with first-principles-based machine-learned molecular dynamics simulations, we found that the vibrational density of states in the superionic state strongly deviates from the quadratic behaviour expected from the Debye law of lattice dynamics. The superionic dynamics emerges from overdamped phonon quasiparticles to give rise to a linear density of states characteristic of instantaneous normal modes in the liquid state. Further, we showed that the coupling of lattice phonons with a dynamic breathing of the Li+ diffusion bottleneck enables an order-of-magnitude increase in diffusivity. Thus, our results shed insights into superionics for future energy storage and conversion technologies.

25 ENERGY STORAGE↗
DOE OSTI2026

Direct measurement of electron heating in electron-only reconnection in a laboratory mini-magnetosphere

We report on the experimental observation of electron heating in electron-only magnetic reconnection in laser-driven laboratory mini-magnetosphere on the Large Plasma Device (LAPD) at the University of California, Los Angeles. In this experiment, a fast-flowing plasma impacts a pulsed magnetic dipole embedded within LAPD’s magnetized ambient plasma, creating an ion-scale magnetosphere and driving electron-only magnetic reconnection between the background and dipole field lines. The electron velocity distribution is measured across the reconnection region using noncollective Thomson scattering, enabling determination of electron temperature and density. Significant electron heating is observed in the electron diffusion region, increasing from an initial temperature of 1.8 to 9.5 eV, corresponding to a 40% local conversion of Poynting flux into electron enthalpy flux. Particle-in-cell simulations that provide insights into the heating mechanisms are also presented.

Rovige, Lucas [Department of Physics and Astronomy↗
DOE OSTI2021

Space-Charge and Other Effects in Fermilab Booster and IOTA Rings’ Ionization Profile Monitors

Ionization profile monitors (IPMs) are widely used in accelerators for non-destructive and fast diagnostics of high energy particle beams. At low beam intensities, initial velocities of the secondaries to collect (ions or electrons) result in the IPM profile smearing. At high beam intensities, the space-charge forces make the measured IPM profiles significantly different from those of the beams. We analyze dynamics of the secondaries in IPMs, describe an effective algorithm to reconstruct the beam sizes from the measured IPM profiles and apply it to the Fermilab 8 GeV proton Booster and 70 MeV/c IOTA ring IPMs.

Shiltsev, Vladimir D.↗
NASA NTRS1983

Collisionless electron shocks in electron-beam-plasma systems

One-dimensional Vlasov simulations show that when an electron beam is suddenly injected into a plasma, a fast-moving monotonic shock forms during the early stage of the transient plasma response. In the shock, the ions are nearly immobile. The shock appears to be an electrostatic electron-beam-plasma mode. The shock evolves from an initial positive potential perturbation, which is supported by an ion burst. The steepening of the perturbation into a shock is characterized by an electron-beam-plasma mode.

Singh, N.↗
NASA NTRS1995

The origin of the solar wind

The high speed solar wind, which is associated with coronal holes and unipolar interplanetary magnetic field, has now been observed in situ beyond 0.3 a.u. and at latitudes up to 80 degrees. Its important characteristics are that it is remarkably steady in terms of flow properties and composition and that the ions, especially minor species, are favored in terms of heating and acceleration. We have proposed that the high speed wind, with its associated coronal holes, forms the basic mode of solar wind flow. In contrast, the low speed wind is inherently non-stationary, filamentary and not in equilibrium with conditions at the coronal base. It is presumably the result of continual reconfigurations of the force-free magnetic field in the low-latitude closed corona which allow trapped plasma to drain away along transiently open flux tubes. Observations of high speed solar wind close to its source are hampered by the essential heterogeneity of the corona, even at sunspot minimum. In particular it is difficult to determine more than limits to the density, temperature and wave amplitude near the coronal base as a result of contamination from fore- and back-ground plasma. We interpret the observations as indicating that the high speed solar wind originates in the chromospheric network, covering only about 1% of the surface of the sun, where the magnetic field is complex and not unipolar. As a result of small-scale reconnection events in this 'furnace', Alfven waves are generated with a flat spectrum covering the approximate range 10 kHz to 10 Hz. The plasma is likely to be produced as a result of downwards thermal conduction and possibly photoionization at the top of the low density chromospheric interface to the furnace, thus controlling the mass flux in the wind. The immediate source of free (magnetic) energy is in the form of granule-sized loops which are continually carried into the network from the sides. The resulting wave spectrum is such that energy can be efficiently transferred to the ions within a few solar radii of the base of the corona, favoring heavy species and creating stable, fast solar wind.

Axford, W. I.↗
NASA NTRS2011

Polymeric Materials With Additives for Durability and Radiation Shielding in Space

Polymeric materials are attractive for use in space structures because of their light weight and high strength In addition, polymers are made of elements with low atomic numbers (Z), primarily carbon (C), hydrogen (H), oxygen (0), and nitrogen (N) which provide the best shielding from galactic cosmic rays (GCR) (ref. 1). Galactic cosmic rays are composed primarily of nuclei (i.e., fully ionized atoms) plus a contribution of about 2% from electrons and positrons. There is a small but significant component of GCR particles with high charge (Z > 10) and high energy (E >100 GeV) (ref. 2). These so-called HZE particles comprise only 1 to 2% of the cosmic ray fluence but they interact with very high specific ionization and contribute 50% of the long- term dose to humans. The best shield for this radiation would be liquid hydrogen, which is not feasible. For this reason, hydrogen-containing polymers make the most effective practical shields. Moreover, neutrons are formed in the interactions of GCR particles with materials. Neutrons can only lose energy by collisions or reactions with a nucleus since they are uncharged. This is a process that is much less probable than the Coulombic interactions of charged particles. Thus, neutrons migrate far from the site of the reaction in which they were formed. This increases the probability of neutrons reaching humans or electronic equipment. Fast neutrons (> 1 MeV) can interact with silicon chips in electronic equipment resulting in the production of recoil ions which can cause single event upsets (SEU) in sensitive components (ref. 3). Neutrons lose energy most effectively by elastic collisions with light atoms, particularly hydrogen atoms. Therefore, hydrogen-containing polymers are not only effective in interacting with GCR particles; they are also effective in reducing the energy of the neutrons formed in the interactions.

Kiefer, Richard↗
DOE OSTI2022

Extreme fast charge aging: Effect of electrode loading and NMC composition on inhomogeneous degradation in graphite bulk and electrode/electrolyte interface

Empowering extreme fast charging (XFC) requires a comprehensive understanding of its application with advanced anode and cathode materials in lithium-ion batteries. No report exists for the full extent of limitations for the anode with crosstalk effect from paired cathode as well as Li plating due to electrode loading under XFC. In this study, a combination of cell testing and multiple length characterization is used to investigate XFC aging mechanism in cells with a low loading of 1.5 mAh cm -2 and high loading of 2.5 mAh cm -2 for graphite (Gr)/Ni-rich LiNi x Mn y Co 1-x-y O 2 (NMCs). Operando XRD mappings show 1.5 mAh cm -2 loadings result in higher strain in graphite for all three cathode types. Among the three NMC cathodes, the graphite from NMC532 and NMC811 cells show comparable strain. Scanning electron microscopy (SEM) images show distinct differences between 6-C-charged anodes in two loadings. Significantly increased electrode thickness can be seen due to more damage in the graphite bulk and accumulation of the electrolyte decomposition products in electrode pores. X-ray photoelectron spectroscopy (XPS) reveals both cathode chemistry and Li plating influence the non-uniform SEI composition on graphite surface. We report higher Ni content in NMC811 promotes the higher levels of salt decomposition on the SEI and formation of higher mass of electrolyte aging products.

25 ENERGY STORAGE↗
DOE OSTI2022

A classical model for three-body interactions in aqueous ionic systems

We present a classical induction model to evaluate the three-body ion–water–water (I–W–W) and water–water–water (W–W–W) interactions in aqueous ionic systems. The classical description of the induction energy is based on electrostatic distributed multipoles up to hexadecapole and distributed polarizabilities up to quadrupole–quadrupole on the O and H atoms of water. The monatomic ions were described by a point charge and a dipole–dipole polarizability, while for the polyatomic ions, distributed multipoles up to hexadecapole and distributed polarizabilities up to quadrupole–quadrupole were used. The accuracy of the classical model is benchmarked against an accurate dataset of 936 (I–W–W) and 2184 (W–W–W) three-body terms for 13 different monatomic and polyatomic cation and anion systems. The classical model shows excellent agreement with the reference second order Moller–Plesset and coupled-cluster single double and perturbative triple [CCSD(T)] three-body energies. The Root-Mean-Square-Errors (RMSEs) for monatomic cations, monatomic anions, and polyatomic ions were 0.29, 0.25, and 0.12 kcal/mol, respectively. The corresponding RMSE for 1744 CCSD(T)/aVTZ three-body (W–W–W) energies, used to train MB-pol, was 0.12 kcal/mol. The accuracy of the proposed classical model demonstrates that the three-body term for aqueous ionic systems can be accurately modeled classically. This approach provides a fast, efficient, and as-accurate path toward modeling the three-body term in aqueous ionic systems that is fully transferable across systems with different ions without the need to fit to tens of thousands of ab initio calculations for each ion to extend existing many-body force fields to interactions between water and ions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗