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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Achieving ultrahigh modulus of resilience and enhanced thermal stability in ZnO x /SU-8 interpenetrating network polymer nanocomposite nanopillars

The modulus of resilience, a mechanical property that quantifies the maximum strain energy density a material can store during elastic deformation, is a crucial parameter for materials used in flexible displays, micro/nano-electro-mechanical system (M/NEMS) actuators, and ultra-sensitive pressure sensors. In this study, ZnO x /SU-8 nanocomposite nanopillars with a diameter of 300 nm, fully infiltrated with a uniformly distributed, interpenetrating amorphous ZnO x filler network, were synthesized via vapor-phase infiltration (VPI). In-situ uniaxial nano-compression tests revealed that the modulus of resilience of ZnO x /SU-8 reaches ∼ 12 MJ/m 3 , which is an ultrahigh value among all engineering materials with comparable strength. In addition, the synthesis fidelity, inorganic infiltration depth, and mechanical performance were all significantly improved compared to VPI-synthesized AlO x nanocomposites. Thermal stability, another key requirement for M/NEMS device materials operating under extreme environments, was also notably enhanced. Furthermore, partial crystallization of the amorphous ZnO x fillers during annealing contributed to an additional increase in modulus of resilience, reaching up to ∼ 13.9 MJ/m 3 . This work presents an effective fabrication strategy for producing nanostructured organic–inorganic hybrid nanocomposites with ultrahigh modulus of resilience and superior thermal stability, paving the way for their integration into next-generation flexible displays and high-performance M/NEMS devices working under harsh environments.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Synergy of carbonyl and azo chemistries for wide-temperature-range rechargeable aluminum organic batteries

Rechargeable aluminum organic batteries (RAOBs) are promising for developing cost-effective and sustainable energy storage devices due to the low cost, abundance, and high sustainability of aluminum and organic resources. In this study, we designed and synthesized a redox-active polymer bearing carbonyl and azo groups as a cathode material for RAOBs. The polymeric cathode exhibits a high reversible specific capacity, superior cyclic stability, fast charging capability, and a wide operation temperature range (₋40°C to 100°C). X-ray photoelectron spectroscopy (XPS), pair distribution function (PDF) analysis, and soft X-ray absorption near edge structure (XANES) were employed to gain fundamental insight into the carbonyl and azo chemistries in RAOBs, as well as the cathode electrolyte interphase (CEI) structure. We demonstrated a step-by-step alumination/de-alumination reaction for carbonyl and azo groups in the polymer cathode and unraveled a Al 2 O 3⁻ and AlN-rich CEI, which is critical for the impressive performance of RAOBs.

25 ENERGY STORAGE↗
DOE OSTI2017

Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes

Here, surface coating of cathode materials with Al 2 O 3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition changes the chemical composition, morphology and distribution of coating within cathode interface and bulk lattice, is still missing. In this study, we use a wet-chemical method to synthesize a series of Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiCoO 2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity and morphology of coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly depended on the annealing temperature and cathode composition. For Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 , higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al 2 O 3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al 2 O 3 -coated LiCoO 2 , the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from “surface coatings” to “dopants”, which is not observed for LiNi 0.5 Co 0.2 Mn 0.3 O 2 . As a result, Al 2 O 3 -coated LiCoO 2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

25 ENERGY STORAGE↗
DOE OSTI2018

Mechanical Properties and Chemical Reactivity of Li x SiO y Thin Films

Silicon (Si) is a commonly studied candidate material for next-generation anodes in Li-ion batteries. A native oxide SiO 2 on Si is often inevitable. However, it is not clear if this layer has a positive or negative effect on the battery performance. This understanding is complicated by the lack of knowledge about the physical properties of the SiO 2 lithiation products and by the convolution of chemical and electrochemical effects during the anode lithiation process. In this study, Li x SiO y thin films as model materials for lithiated SiO 2 were deposited by magnetron sputtering at ambient temperature, with the goal of (1) decoupling chemical reactivity from electrochemical reactivity and (2) evaluating the physical and electrochemical properties of Li x SiO y . X-ray photoemission spectroscopy analysis of the deposited thin films demonstrate that a composition close to previous experimental reports of lithiated native SiO 2 can be achieved through sputtering. Our density functional theory calculations also confirm that the possible phases formed by lithiating SiO 2 are very close to the measured film compositions. Scanning probe microscopy measurements show that the mechanical properties of the film are strongly dependent on lithium concentration, with a ductile behavior at a higher Li content and a brittle behavior at a lower Li content. The chemical reactivity of the thin films was investigated by measuring the AC impedance evolution, suggesting that Li x SiO y continuously reacts with the electrolyte, in part because of the high electronic conductivity of the film determined from solid-state impedance measurements. The electrochemical cycling data of the sputter-deposited Li x SiO y /Si films also suggest that Li x SiO y is not beneficial in stabilizing the Si anode surface during battery operation, despite its favorable mechanical properties.

14 SOLAR ENERGY↗
DOE OSTI2026

Chemical and Structural Insights into Solid Electrolyte Interphase Evolution for Sodium Metal Electrodes

The solid electrolyte interphase (SEI) critically governs the reversibility of sodium metal batteries, through dynamically mediating ion transport and interfacial reactions. However, its kinetic evolution under operating conditions, and how it influences interfacial stability, remains poorly understood. Here, in this study, we reveal that the SEI undergoes coupled chemical and mechanical changes during sodium plating and stripping, leading to spatial and temporal heterogeneity that drives interfacial degradation. Synchrotron operando grazing-incidence wide-angle X-ray scattering and soft X-ray absorption spectroscopy capture the sequential formation and dissolution of inorganic SEI phases (NaF, NaH, NaOH, Na 2 PO 3 F), accompanied by depth-dependent alterations in organic SEI components. Mesoscale modeling connects this evolving SEI heterogeneity to localized current density fluctuations and stress accumulation at the Na interface, identifying pathways to electrically isolated sodium formation. These findings show that SEI instability fundamentally limits reversibility in sodium metal batteries, and that controlling SEI chemistry–mechanics coupling is essential to achieving its durability.

36 MATERIALS SCIENCE↗
DOE OSTI2011

An X-ray Absorption Spectroscopy Study of the Cathodic Discharge of Ag2VO2PO4: Geometric and Electronic Structure Characterization of Intermediate Phases and Mechanistic Insights

Bimetallic phosphorus oxides have emerged as attractive candidates for use as cathode materials in the next generation of lithium-based batteries owing to the operation of multielectron transfer processes and thermochemical stabilities conferred by the incorporation of phosphate groups. In particular silver vanadium phosphorus oxide, Ag{sub 2}VO{sub 2}PO{sub 4}, shows a much desired in situ conductivity enhancement upon discharge resulting in inherently high power capability with minimal conductive additives needed. However, the amorphization of Ag{sub 2}VO{sub 2}PO{sub 4} during electrochemical discharge precludes the use of standard diffraction tools to monitor changes in the local electronic and geometric structure. Here, we have utilized a combination of V K-, V L-, Ag K-, and O K-edge X-ray absorption fine structure spectroscopy to determine the local vanadium and silver oxidation states, local coordination geometry, and stoichiometry for Ag{sub 2}VO{sub 2}PO{sub 4} samples with varying extents of electrochemical lithiation. Soft X-ray V L- and O K-edge measurements provide a detailed orbital-specific picture of changes in vanadium electronic structure upon discharge.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Breaking the scaling relationship via thermally stable Pt/Cu single atom alloys for catalytic dehydrogenation

Here, noble-metal alloys are widely used as heterogeneous catalysts. However, due to the existence of scaling properties of adsorption energies on transition metal surfaces, the enhancement of catalytic activity is frequently accompanied by side reactions leading to a reduction in selectivity for the target product. Herein, we describe an approach to breaking the scaling relationship for propane dehydrogenation, an industrially important reaction, by assembling single atom alloys (SAAs), to achieve simultaneous enhancement of propylene selectivity and propane conversion. We synthesize γ-alumina-supported platinum/copper SAA catalysts by incipient wetness co-impregnation method with a high copper to platinum ratio. Single platinum atoms dispersed on copper nanoparticles dramatically enhance the desorption of surface-bounded propylene and prohibit its further dehydrogenation, resulting in high propylene selectivity (~90%). Unlike previous reported SAA applications at low temperatures (<400 °C), Pt/Cu SAA shows excellent stability of more than 120 h of operation under atmospheric pressure at 520 °C.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Water as a gas separation membrane

Efficient gas separation membranes are essential for carbon capture, biogas upgrading, and hydrogen purification. Inspired by how plants absorb CO 2 through water, we present a membrane platform that uses liquid water as the selective layer. Hydrophilic sub-100-nm pores stabilize water through strong capillary forces, enabling operation at feed pressures above 72 bar under dry and humid conditions. Selectivity is governed by gas solubility in water, while permeance is tuned by adjusting the water layer thickness. Reducing this thickness below 200 nm yields CO 2 permeances up to 11,600 gas permeation units with CO 2 :N 2 , CO 2 :CH 4 , and CO 2 :H 2 selectivities of 40, 26, and 31, respectively, surpassing the performance of state-of-the-art membranes. Operation is sustained for over a week without water loss, and performance scales using commercially available porous polymer supports under mixed-gas crossflow conditions. Water’s dissolution-based transport avoids saturation and reaction-rate limits, enabling a robust, high-performance, and environmentally benign gas separation platform.

08 HYDROGEN↗
DOE OSTI2018

Empowering multicomponent cathode materials for sodium ion batteries by exploring three-dimensional compositional heterogeneities

Affordable sodium ion batteries hold great promise for revolutionizing stationary energy storage technologies. Sodium layered cathode materials are usually multicomponent transition metal (TM) oxides and each TM plays a unique role in the operating cathode chemistry, e.g., redox activity, structural stabilization. Engineering the three-dimensional (3D) distribution of TM cations in individual cathode particles can take advantage of a depth-dependent charging mechanism and enable a path towards tuning local TM–O chemical environments and building resilience against cathode–electrolyte interfacial reactions that are responsible for capacity fading, voltage decay and safety hazards. In this study, we create 3D compositional heterogeneity in a ternary and biphasic (O3–P3) sodium layered cathode material (Na 0.9 Cu 0.2 Fe 0.28 Mn 0.52 O 2 ). The cells containing this material deliver stable voltage profiles, and discharge capacities of 125 mA h g –1 at C/10 with almost no capacity fading after 100 cycles and 75 mA h g –1 at 1C with negligible capacity fading after 200 cycles. The direct performance comparison shows that this material outperforms other materials with similar global compositions but different mesoscale chemical distributions. Synchrotron X-ray spectroscopy/imaging and density functional theory studies reveal depth-dependent chemical environments due to changes to factors such as charge compensation and strength of orbital hybridization. Finally, 3D spectroscopic tomography illuminates the path towards optimizing multicomponent sodium layered cathode materials, to prevent the migration of TMs upon prolonged cycling. Furthermore, the study reports an inaugural effort of multifaceted and counterintuitive investigation of sodium layered cathode materials and strongly implies that there is plenty of room at the bottom by tuning nano/meso scale chemical distributions for stable cathode chemistry.

25 ENERGY STORAGE↗
DOE OSTI2021

Modelling and control coordination scheme of a wind‐to‐hydrogen set for future renewable‐based power systems

New challenges regarding system stability and efficiency arise when power systems operate with a high penetration level of inverter‐based renewable sources (IBRSs) and few synchronous generators. Since IBRSs have been on the rise, to secure the stable operation of future power systems, IBRSs will be required to support systems without having to rely on remaining synchronous generators. Also, to efficiently manage the uncertainty of renewable production, power‐to‐gas technology can provide the required flexibility. This study proposes modelling and a control coordination scheme (CCS) of a wind‐to‐hydrogen (W2H) set to optimise electricity production from a variable‐speed wind turbine generator (WTG) while helping balance between supply and demand in a system. To achieve this, a grid‐forming (GFM) inverter‐based WTG is modelled and a set of electrolyser and fuel cell is integrated at the DC circuit of a GFM‐WTG to be coordinated. Furthermore, the CCS offers an opportunity to reduce the investment cost for deploying a W2H set by utilising the control capabilities of a WTG and reducing the need for an additional device. The performance of the proposed W2H set with the CCS was verified considering the variations in system load and wind speed by using Power System Computer Aided Design (PSCAD)/ElectroMagnetic Transients including Direct Current (EMTDC).

Kim, Jinho↗
DOE OSTI2014

Heating and current drive requirements towards steady state operation in ITER

Steady state scenarios envisaged for ITER aim at optimizing the bootstrap current, while maintaining sufficient confinement and stability to provide the necessary fusion yield. Non-inductive scenarios will need to operate with Internal Transport Barriers (ITBs) in order to reach adequate fusion gain at typical currents of 9 MA. However, the large pressure gradients associated with ITBs in regions of weak or negative magnetic shear can be conducive to ideal MHD instabilities, reducing the no-wall limit. The E × B flow shear from toroidal plasma rotation is expected to be low in ITER, with a major role in the ITB dynamics being played by magnetic geometry. Combinations of H/CD sources that maintain weakly reversed magnetic shear profiles throughout the discharge are the focus of this work. Time-dependent transport simulations indicate that, with a trade-off of the EC equatorial and upper launcher, the formation and sustainment of quasi-steady state ITBs could be demonstrated in ITER with the baseline heating configuration. However, with proper constraints from peeling-ballooning theory on the pedestal width and height, the fusion gain and the maximum non-inductive current are below the ITER target. Upgrades of the heating and current drive system in ITER, like the use of Lower Hybrid current drive, could overcome these limitations, sustaining higher non-inductive current and confinement, more expanded ITBs which are ideal MHD stable.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Cement sensors with acoustic bandgaps using carbon nanotubes

Cement is widely used in wellbores to stabilize the steel casing used in wellbore operations for oil and gas production, enhanced geothermal systems and carbon sequestration, and to limit fluid movement between sub-surface strata. Flaws such as microcracks in wellbore cement can lead to leakage along the wellbore compromising wellbore integrity. There is an increasing need for methods to monitor cement crack propagation in wellbore environments. In this study, we develop and report the first cementitious sensors capable of exhibiting high frequency acoustic bandgaps (ABGs) using carbon nanotubes (CNTs). Computational simulations of a sensor unit cell are used to design cement-multi walled carbon nanotubes (MWCNTs) sensors that show a wide bandgap. When the cement-MWCNTs sensors is embedded in cement specimens, bandgaps were measured experimentally under 300 kHz and under 600 kHz, consistent with the computationally predicted bandgaps in the range of 290–360 kHz, 410–460 kHz and 515–585 kHz. These bandgap features were absent in homogeneous cement specimens. X-ray tomographic reconstructions showed microscopic debonding at cement-MWCNTs sensor interface. Frequency response analysis of a three-dimensional computational model indicated a shift of frequency of minimum transmission due to the interface debonding, but no perturbation of bandgap response was observed. Here, the cement-MWCNTs sensors developed in this study show the potential of a packed CNT inclusion material in cementitious matrix to create ABGs in a cement matrix.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Renormalization group study of the minimal Majoronic dark radiation and dark matter model

We study the 1-loop renormalization group equation running in the simplest singlet Majoron model constructed by us earlier to accommodate the dark radiation and dark matter content in the universe. A comprehensive numerical study was performed to explore the whole model parameter space. A smaller effective number of neutrinos △N{sub eff}∼0.05, or a Majoron decoupling temperature higher than the charm quark mass, is preferred. We found that a heavy scalar dark matter, ρ, of mass 1.5–4 TeV is required by the stability of the scalar potential and an operational type-I see-saw mechanism for neutrino masses. A neutral scalar, S, of mass in the 10–100 GeV range and its mixing with the standard model Higgs as large as 0.1 is also predicted. The dominant decay modes are S into bb-bar and/or ωω. A sensitive search will come from rare Z decays via the chain Z→S+ff-bar, where f is a Standard Model fermion, followed by S into a pair of Majoron and/or b-quarks. The interesting consequences of dark matter bound state due to the sizable Sρρ-coupling are discussed as well. In particular, shower-like events with an apparent neutrino energy at M{sub ρ} could contribute to the observed effective neutrino flux in underground neutrino detectors such as IceCube.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Use of differential plasma rotation to prevent disruptive tearing mode onset from 3-wave coupling

Abstract Plasma differential rotation is found to be capable of preventing disruptive neoclassical tearing modes (NTMs) seeded by nonlinear three-wave coupling. As tearing modes degrade confinement and can lead to disruptions, stabilization strategies are crucial to the successful operation of future devices. In ITER-relevant scenarios on DIII-D, rotationally coupled m / n = 1/1 and 3/2 modes have been observed to drive 2/1 islands through three-wave coupling. The frequency of the driven 2/1 mode is set by matching conditions and the frequencies of the driving modes. When the driven mode frequency matches the local plasma rotation frequency, e.g. at low differential rotation, the driven 2/1 island can grow into a disruptive NTM. Using neutral beam torque as an actuator to scan the differential rotation, these experiments demonstrate that a sufficiently large frequency mismatch prevents destabilization of disruptive 2/1 NTMs by three-wave coupling. This work indicates that differential rotation can be used as an actuator to prevent NTMs seeded by three-wave coupling.

Richner, N. J. (ORCID:0000000155443915)↗
DOE OSTI2012

Distributed error and alarm processing in the CMS data acquisition system

The error and alarm system for the data acquisition of the Compact Muon Solenoid (CMS) at CERN was successfully used for the physics runs at Large Hadron Collider (LHC) during first three years of activities. Error and alarm processing entails the notification, collection, storing and visualization of all exceptional conditions occurring in the highly distributed CMS online system using a uniform scheme. Alerts and reports are shown on-line by web application facilities that map them to graphical models of the system as defined by the user. A persistency service keeps a history of all exceptions occurred, allowing subsequent retrieval of user defined time windows of events for later playback or analysis. This paper describes the architecture and the technologies used and deals with operational aspects during the first years of LHC operation. In particular we focus on performance, stability, and integration with the CMS sub-detectors.

Bauer, G.↗
DOE OSTI2024

Ergodicity, lack thereof, and the performance of reservoir computing with memristive networks

Abstract Networks composed of nanoscale memristive components, such as nanowire and nanoparticle networks, have recently received considerable attention because of their potential use as neuromorphic devices. In this study, we explore ergodicity in memristive networks, showing that the performance on machine leaning tasks improves when these networks are tuned to operate at the edge between two global stability points. We find this lack of ergodicity is associated with the emergence of memory in the system. We measure the level of ergodicity using the Thirumalai-Mountain metric, and we show that in the absence of ergodicity, two different memristive network systems show improved performance when utilized as reservoir computers (RC). We highlight that it is also important to let the system synchronize to the input signal in order for the performance of the RC to exhibit improvements over the baseline.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

On Parallelizing Single Dynamic Simulation Using HPC Techniques and APIs of Commercial Software

Time-domain simulations are heavily used in today’s planning and operation practices to assess power system transient stability and post-transient voltage/frequency profiles following severe contingencies to comply with industry standards. Because of the increased modeling complexity, it is several times slower than real time for state-of-the-art commercial packages to complete a dynamic simulation for a large-scale model. With the growing stochastic behavior introduced by emerging technologies, power industry has seen a growing need for performing security assessment in real time. This paper presents a parallel implementation framework to speed up a single dynamic simulation by leveraging the existing stability model library in commercial tools through their application programming interfaces (APIs). Several high performance computing (HPC) techniques are explored such as parallelizing the calculation of generator current injection, identifying fast linear solvers for network solution, and parallelizing data outputs when interacting with APIs in the commercial package, TSAT. The proposed method has been tested on a WECC planning base case with detailed synchronous generator models and exhibits outstanding scalable performance with sufficient accuracy.

Diao, Ruisheng↗
DOE OSTI2023

Out-of-plane ferroelectricity and robust magnetoelectricity in quasi-two-dimensional materials

Thin-film ferroelectrics have been pursued for capacitive and nonvolatile memory devices. They rely on polarizations that are oriented in an out-of-plane direction to facilitate integration and addressability with complementary metal-oxide semiconductor architectures. The internal depolarization field, however, formed by surface charges can suppress the out-of-plane polarization in ultrathin ferroelectric films that could otherwise exhibit lower coercive fields and operate with lower power. Here, we unveil stabilization of a polar longitudinal optical (LO) mode in the n = 2 Ruddlesden–Popper family that produces out-of-plane ferroelectricity, persists under open-circuit boundary conditions, and is distinct from hyperferroelectricity. Our first-principles calculations show the stabilization of the LO mode is ubiquitous in chalcogenides and halides and relies on anharmonic trilinear mode coupling. We further show that the out-of-plane ferroelectricity can be predicted with a crystallographic tolerance factor, and we use these insights to design a room-temperature multiferroic with strong magnetoelectric coupling suitable for magneto-electric spin-orbit transistors.

36 MATERIALS SCIENCE↗