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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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Valuation of Anode Materials for High-Performance Lithium Batteries: From Graphite to Lithium Metal and Beyond

Lithium-ion batteries have revolutionized energy storage, yet advanced technologies such as electric vehicles and eVTOLs demand even higher performance and safety. Anodes, the negative electrodes, are crucial in enhancing batteries’ safety, lifespan, and fast-charging capabilities. This review paper comprehensively evaluates the progression of anode materials from traditional graphite to advanced anodes like lithium metal. Graphite anodes, with a capacity of 372 mAh g −1 , enabled the first commercial lithium-ion batteries, but future applications require higher energy densities and fast-charging capabilities. Emerging anode materials, including alloying, and conversion types, as well as lithium metal, offer significantly higher capacities, with lithium metal offering a theoretical capacity of 3 860 mAh g −1 . However, these advanced anodes face challenges such as volume expansion, high surface reactivity, sluggish Li+ kinetics, and unstable lithium deposition morphologies. Here, this review critically examines the electrochemical performance, interfacial properties, mechanical attributes, and stability issues of various anode materials. It further discusses solid electrolyte interphase (SEI) formation, strategies for enhancing interface stability, and the requirements of anodes for solid-state batteries. Additionally, the review explores potential solutions for limitations with each anode type, highlights innovative anode-free architectures, and evaluates the current and future trends of battery anode industries. Ultimately, this paper aims to guide the development of high-performance anode materials, paving the way for the next generation of efficient, reliable lithium batteries.

Alloying anodes↗
DOE OSTI2026

Surface-Initiated Atom Transfer Radical Polymerization Using Hydrogel Reactors

Atom transfer radical polymerization (ATRP) is a controlled radical polymerization method that enables the synthesis of tailored polymeric materials with low dispersity, highlighting its immense potential for green fabrication of advanced materials. However, its broader implementation is limited by challenges in product isolation, maintaining catalyst activity, and mitigating atmospheric sensitivity arising from oxygen-sensitive metal catalysts. Here, gelatin hydrogels (GHs) are introduced as a soft “reactor” matrix for interfacial ATRP, operating with minimal metal-catalyst loading while exhibiting possibly an organoreductive behavior. This strategy leverages activator regeneration via electron transfer through a ligand–metal charge-transfer (LMCT) mechanism to reduce oxidized metal catalysts within the GH network. Polymerization is evaluated by growing polymer brushes at an active interface formed between GHs swollen in monomer solution and an initiating surface, and sequential growth experiments confirmed that GH-mediated ATRP preserves living character. Under UV illumination, LMCT is activated, producing polymers both at the desired interface and within the GH bulk. UV–Vis spectroscopy revealed active reduction of Cu(II) to Cu(I) along with concentration-dependent complex formation, indicating dynamic coordination chemistry within the hydrogel. The redox-active arginine- and glutamic acid-rich gelatin backbone coordinates and reduces the metal center, enabling ATRP at ppm-level catalyst concentrations. While polymerization proceeds in GH-Cu(II) reactors, adding external mobile ligands to the GH results in longer polymer brushes. Here, the results reported here are exploratory. More experiments are needed to characterize polymer brush growth in GHs and compare it to conventional surface-initiated polymerization in solution.

Absorption↗
DOE OSTI2023

Structural insights into opposing actions of neurosteroids on GABA A receptors

γ-Aminobutyric acid type A (GABA A ) receptors mediate fast inhibitory signaling in the brain and are targets of numerous drugs and endogenous neurosteroids. A subset of neurosteroids are GABA A receptor positive allosteric modulators; one of these, allopregnanolone, is the only drug approved specifically for treating postpartum depression. There is a consensus emerging from structural, physiological and photolabeling studies as to where positive modulators bind, but how they potentiate GABA activation remains unclear. Other neurosteroids are negative modulators of GABA A receptors, but their binding sites remain debated. Here we present structures of a synaptic GABA A receptor bound to allopregnanolone and two inhibitory sulfated neurosteroids. Allopregnanolone binds at the receptor-bilayer interface, in the consensus potentiator site. In contrast, inhibitory neurosteroids bind in the pore. MD simulations and electrophysiology support a mechanism by which allopregnanolone potentiates channel activity and suggest the dominant mechanism for sulfated neurosteroid inhibition is through pore block.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Structural basis of the activation of a metabotropic GABA receptor

Metabotropic γ-aminobutyric acid receptors (GABA B ) are involved in the modulation of synaptic responses in the central nervous system and have been implicated in neuropsychological conditions that range from addiction to psychosis. GABA B belongs to class C of the G-protein-coupled receptors, and its functional entity comprises an obligate heterodimer that is composed of the GB1 and GB2 subunits. Each subunit possesses an extracellular Venus flytrap domain, which is connected to a canonical seven-transmembrane domain. In this paper we present four cryo-electron microscopy structures of the human full-length GB1–GB2 heterodimer: one structure of its inactive apo state, two intermediate agonist-bound forms and an active form in which the heterodimer is bound to an agonist and a positive allosteric modulator. The structures reveal substantial differences, which shed light on the complex motions that underlie the unique activation mechanism of GABA B . Our results show that agonist binding leads to the closure of the Venus flytrap domain of GB1, triggering a series of transitions, first rearranging and bringing the two transmembrane domains into close contact along transmembrane helix 6 and ultimately inducing conformational rearrangements in the GB2 transmembrane domain via a lever-like mechanism to initiate downstream signalling. This active state is stabilized by a positive allosteric modulator binding at the transmembrane dimerization interface.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Carbon dioxide and nitrogen reduction reactions using 2D transition metal dichalcogenide (TMDC) and carbide/nitride (MXene) catalysts

Improving the carbon dioxide and nitrogen reduction reactions (CO 2 RR and NRR) can reduce anthropogenic greenhouse gas emissions while selectively producing chemicals needed for the fuel, plastic, and chemical industries. Efficient CO 2 RR can be used to replace fossil fuels as well as repurpose captured CO 2 , while new NRR pathways can be used to supplement or replace the energy intensive Haber–Bosch process for NH 3 generation with no CO 2 emissions. Therefore, this review article focuses on (photo)electrocatalytic and photocatalytic conversion of CO 2 and N 2 molecules into useful products, such as carbon monoxide, methanol, formic acid, and ammonia, using 2D transition metal dichalcogenides (TMDCs) and metal carbides/nitrides (MXenes). Additionally, these highly tunable 2D catalysts will be evaluated for their ability to selectively and efficiently undergo CO 2 RR and NRR by controlling defects, phases, edge sites, interfaces, and functional groups. We first address the CO 2 RR and NRR challenges, with a particular focus on theoretical mechanisms and minimum energy pathways. We follow this discussion with a detailed review of state-of-the-art 2D TMDC and MXene experimental catalysts for CO 2 RR and NRR (photo)electrocatalytic and photocatalytic reactions, and then address areas of opportunity for these catalytic reactions.

14 SOLAR ENERGY↗
DOE OSTI2021

In situ Al 2 O 3 incorporation enhances the efficiency of CuIn(S,Se) 2 solar cells prepared from molecular-ink solutions

Here, we report an efficiency enhancement of solution-processed CuIn(S,Se) 2 (CISSe) thin film solar cells via in situ incorporation of Al 2 O 3 . These films were produced using inks containing CuCl, InCl 3 , AlNO 3 (Al/Al + In: 0.1) and thiourea dissolved in methanol. After spin coating of these solutions in air, samples were subjected to a selenization process. Auger electron spectroscopy depth-profiling analysis showed that Al is evenly distributed throughout the bulk of the film. Transmission electron microscopy revealed that AlNO 3 precursor reacted with oxygen to form nanosized amorphous Al 2 O 3 grains located within the bulk and grain boundaries of CISSe, as well as at both the top and bottom interfaces. Power conversion efficiency (PCE) as high as 11.6% (JS C : 35.8 mA cm –2 , V OC : 518 mV, FF: 62.2%, no anti-reflection coating) was achieved with Al–CISSe solar cell devices integrated with CdS (chemical bath deposition, thickness: 80 nm) and ZnO/ITO bilayers (sputtered, thickness: 300 nm). The average PCE (10.1%, $\langle$J SC $\rangle$: 34.5 mA cm –2 , $\langle$V OC $\rangle$: 491 mV, $\langle$FF$\rangle$: 59.8%) was nearly 4% (absolute) higher than that measured on CISSe baseline cells fabricated from solutions without Al ($\langle$PCE$\rangle$ = 6.4%, $\langle$J SC $\rangle$: 32.8 mA cm –2 , $\langle$V OC $\rangle$: 410 mV, $\langle$FF$\rangle$: 47.3%). This in situ Al 2 O 3 incorporation is speculated to play a role in the enhancement of the VOC and FF of the devices through passivation of defects in CISSe reducing interface and bulk recombination, as evidenced by a reduced defect density and an increased activation energy of the dominant recombination mechanism from capacitance and temperature-dependent VOC measurements, respectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Dynamics of electrified liquid metal surface using shallow water model

A shallow water model that incorporates surface tension and electric field effects is developed to investigate the dynamics of an electrified liquid surface. The computational model is verified against the Zakharov–Kuznetsov equation and is applied to study the growth and damping of the electrified liquid surface. A linear wave analysis is performed under a shallow water theory assuming an analytic solution of the electric field, similar to the Tonks–Frenkel instability. The electrified liquid surface grows or dampens based on the balance of the electric field, surface tension, and gravitational forces. As a result, the numerical results obtained from the electrified shallow water solver are in good agreement with the theoretical analysis.

Computational models↗
DOE OSTI2020

Energy Flow in Thin Shell Implosions and Explosions

Energy flow and balance in convergent systems beyond petapascal energy densities controls the fate of late-stage stars and the potential for controlling thermonuclear inertial fusion ignition. Time-resolved x-ray self-emission imaging combined with a Bayesian inference analysis is used to describe the energy flow and the potential information stored in the rebounding spherical shock at 0.22 PPa (2.2 Gbar or billions of atmospheres pressure). This analysis, together with a simple mechanical model, describes the trajectory of the shell and the time history of the pressure at the fuel-shell interface, ablation pressure, and energy partitioning including kinetic energy of the shell and internal energy of the fuel. Here, the techniques used here provide a fully self-consistent uncertainty analysis of integrated implosion data, a thermodynamic-path independent measurement of pressure in the petapascal range, and can be used to deduce the energy ow in a wide variety of implosion systems to petapascal energy densities.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Announcing the Biomedical Data Translator: Initial Public Release

ABSTRACT The growing availability of biomedical data offers vast potential to improve human health, but the complexity and lack of integration of these datasets often limit their utility. To address this, the Biomedical Data Translator Consortium has developed an open‐source knowledge graph–based system—Translator—designed to integrate, harmonize, and make inferences over diverse biomedical data sources. We announce here Translator's initial public release and provide an overview of its architecture, standards, user interface, and core features. Translator employs a scalable, federated, knowledge graph framework for the integration of clinical, genomic, pharmacological, and other biomedical knowledge sources, enabling query retrieval, inference, and hypothesis generation. Translator's user interface is designed to support the exploration of knowledge relationships and the generation of insights, without requiring deep technical expertise and gradually revealing more detailed evidence, provenance, and confidence information, as needed by a given user. To demonstrate Translator's application and impact, we highlight features of the user interface in the context of three real‐world use cases: suggesting potential therapeutics for patients with rare disease; explaining the mechanism of action of a pipeline drug; and screening and validating drug candidates in a model organism. We discuss strengths and limitations of reasoning within a largely federated system and the need for rich concept modeling and deep provenance tracking. Finally, we outline future directions for enhancing Translator's functionality and expanding its data sources. Translator represents a significant step forward in making complex biomedical knowledge more accessible and actionable, aiming to accelerate translational research and improve patient care.

Research & Experimental Medicine↗
DOE OSTI2024

Prospects for Antiferromagnetic Spintronic Devices

This article examines recent advances in the field of antiferromagnetic spintronics from the perspective of potential device realization and applications. We discuss advances in the electrical control of antiferromagnetic order by current-induced spin–orbit torques, particularly in antiferromagnetic thin films interfaced with heavy metals. We also review possible scenarios for using voltage-controlled magnetic anisotropy as a more efficient mechanism to control antiferromagnetic order in thin films with perpendicular magnetic anisotropy. Next, we discuss the problem of electrical detection (i.e., readout) of antiferromagnetic order and highlight recent experimental advances in realizing anomalous Hall and tunneling magnetoresistance effects in thin films and tunnel junctions, respectively, which are based on noncollinear antiferromagnets. Understanding the domain structure and dynamics of antiferromagnetic materials is essential for engineering their properties for applications. For this reason, we then provide an overview of imaging techniques as well as micromagnetic simulation approaches for antiferromagnets. Finally, we present a perspective on potential applications of antiferromagnets for magnetic memory devices, terahertz sources, and detectors.

36 MATERIALS SCIENCE↗
DOE OSTI2022

High-Density, Actively Multiplexed µECoG Array on Reinforced Silicone Substrate

Simultaneous interrogation of electrical signals from wide areas of the brain is vital for neuroscience research and can aid in understanding the mechanisms of brain function and treatments for neurological disorders. There emerges a demand for development of devices with highly conformal interfaces that can span large cortical regions, have sufficient spatial resolution, and chronic recording capability while keeping a small implantation footprint. In this work, we have designed 61 channel and 48 channel high-density, cortical, micro-electrocorticographic electrode arrays with 400 µm pitch on an ultra-soft but durable substrate. We have also developed a custom multiplexing integrated circuit (IC), methods for packaging the IC in a water-tight liquid crystal polymer casing, and a micro-bonding method for attaching the electronics package to the electrode array. With the integrated multiplexer, the number of external wire connections can be reduced to 16 wires, thereby diminishing the invasive footprint of the device. Both the electrode array and IC were tested in vivo in a rat model to demonstrate the ability to sense finely-localized electrophysiological signals.

Rachinskiy, Iakov↗
DOE OSTI2021

Energy Flow in Thin Shell Implosions and Explosions

Energy flow and balance in convergent systems beyond petapascal energy densities controls the fate of late-stage stars and the potential for controlling thermonuclear inertial fusion ignition. Timeresolved x-ray self-emission imaging combined with a Bayesian inference analysis is used to describe the energy flow and the potential information stored in the rebounding spherical shock at 0.22 petaPascal (2.2 Gbar or billions of atmospheres pressure). This analysis, together with a simple mechanical model, describes the trajectory of the shell and the time history of the pressure at the fuel-shell interface, ablation pressure, and energy partitioning including kinetic energy of the shell and internal energy of the fuel. The techniques used here provide a fully self-consistent uncertainty analysis of integrated implosion data, a thermodynamic-path independent measurement of pressure in the petaPascal range, and can be used to deduce the energy flow in a wide variety of implosion systems to petapascal energy densities.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Unveiling the Reactivity of Fluoropolymers with Sodium Metal: Mechanistic Insights and Battery Implications

Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) has broad applications across various metal-ion battery systems, such as a binder for electrodes, a supporting matrix for electrolytes, and a separator material. Due to its excellent mechanical properties, PVDF-HFP has become an excellent candidate for fabricating gel and solid-state electrolytes in sodium-based batteries. However, in this study, we noticed notable side reactions occurring at the interface of PVDF-HFP membranes and Na metal. These reactions not only alter chemical compositions but also further affect the surface morphology and adhesive properties of membranes. Similar phenomena are observed in other polyfluoroalkyl-based membranes (PVDF and PTFE). Therefore, we systematically studied the reaction mechanisms between the Na metal and these polymers. The influence of different functional groups (−F, −CF 3 , −H) and their arrangement on the reaction extent has also been discussed. Finally, we concluded with the key factors driving these side reactions and provided new perspectives for designing polymers tailored for sodium-based batteries.

Interfacial side reactions↗
DOE OSTI2023

A Micro-scale Numerical Investigation of Internal and Interfacial Void Defects in Adhesive on Failure Behavior of Adhesively-Bonded Materials with Rough Surfaces

This paper studied the effects of air void defects on the failure behavior of adhesively-bonded materials under global shear via micro-scale computational modeling. The numerical results indicated that interfacial void defects can largely facilitate interfacial debonding of a weaker adherend/adhesive interface under shear. However, this is not the case for a stronger adherend/adhesive interface, showing the reduction on the nominal shear strength of an adhesive joint is mainly due to internal void defects. The reduced bonding performance due to voids can be improved by leveraging an appropriate surface roughness. This preliminary investigation is a first step to better understand the micro-mechanics of interfacial failure in the adhesion of a roughened/patterned adherend via surface modification(s) and an adhesive, and also shows the importance of minimizing interfacial void defects in particular at a weaker adherend/adhesive interface via different techniques.

Qiao, Yao↗
DOE OSTI2020

Deep level transient spectroscopy investigation of ultra-wide bandgap ($\bar201$) and ($001$) β -Ga 2 O 3

Here, this work reports on a comprehensive examination of the electrical and thermal properties of vertical Schottky diodes fabricated on ($\bar201$) and ($001$)-oriented samples of β-Ga 2 O 3 . The temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) data were gathered and analyzed down to 60 K. Deep level transient spectroscopy (DLTS) was used to study bulk and interface defects in the two materials from approx. 325 K down to 60 K. In the bulk ($\bar201$) material, an electron trap was observed at E C -0.46 eV, with a capture cross section of 1.6 x 10 -14 cm 2 and a lambda-corrected maximum trap density of 9.08 x 10 15 cm -3 . These results and others indicate that the electron trap is a strong candidate for the well-known E1 defect in β-Ga 2 O 3 based on recent investigations. Additionally, in the ($\bar201$) material, the smooth modulation typical of interface states is evident at temperatures below 275 K. The ($001$) samples manifested what is likely the E2* electron trap at E C -0.68 eV, with a capture cross section of 1.64 x 10 -15 cm 2 and a lambda-corrected maximum trap density of 8.85 x 10 15 cm -3 . The presence of the E2* defect, in particular, is a contrast to the findings of recent DLTS investigations on β-Ga 2 O 3 , which report that E2* emerged only after low-energy proton irradiation. These results help to further map out the defect signatures found in β-Ga 2 O 3 materials, which are of vital importance in the design and fabrication of future β-Ga 2 O 3 devices.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Enabling Magnesium Anodes by Tuning the Electrode/Electrolyte Interfacial Structure

Here, a new deposition mechanism is presented in this study to achieve highly reversible plating and stripping of magnesium (Mg) anodes for Mg-ion batteries. It is known that the reduction of electrolyte anions such as bi s (trifluoromethanesulfonyl) imide (TFSI - ) causes Mg surface passivation, resulting in poor electrochemical performance for Mg-ion batteries. We reveal that the addition of sodium cations (Na + ) in Mg-ion electrolytes can fundamentally alter the interfacial chemistry and structure at the Mg anode surface. The molecular dynamics simulation suggests that Na + cations contribute to a significant population in the interfacial double layer so that TFSI - anions are excluded from the immediate interface adjacent to the Mg anode. As a result, the TFSI - decomposition is largely suppressed so does the formation of passivation layers at the Mg surface. This mechanism is supported by our electrochemical, microscopic, and spectroscopic analyses. The resultant Mg deposition demonstrates smooth surface morphology and lowered overpotential compared to the pure Mg(TFSI) 2 electrolyte.

25 ENERGY STORAGE↗
DOE OSTI2026

Nonequilibrium dynamics of two-level systems directly after cryogenic alternating bias

Two-level systems (TLSs) are a dominant decoherence mechanism in superconducting qubits, microwave kinetic inductance detectors, and quantum dots. TLSs are tunneling states commonly found in amorphous materials and interfaces, which interact electromechanically, leading to energy loss. Fluctuations in the frequency of the TLSs are a significant problem for qubit operation and force recalibration every few hours. In this study, we probe the effect of alternating bias at cryogenic temperatures on TLSs in a purpose-built LC oscillator. When an in situ alternating bias is applied, the steady-state spectra of the TLSs disappear. Spectroscopy reveals transient behavior, in which the TLS frequency fluctuates on the order of minutes. Thermal cycling above 10 K reverses these effects, restoring the TLS spectrum to its original state. Importantly, the intrinsic loss tangent of the LC oscillator remains unchanged before and after the application of the alternating bias. We propose that the disappearance of the steady-state spectrum is caused by nonequilibrium energy buildup from strain in the oxide film introduced by the pulsed voltage-bias sequence. Understanding this nonequilibrium energy could shed light on TLS fluctuations and reduce the calibration requirements for qubits.

general physics↗