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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

High-strength, lightweight nano-architected silica

Continuous nanolattices are an emerging class of mechanical metamaterials that are highly attractive due to their superior strength-to-weight ratios, which originate from their spatial architectures and nanoscale-sized elements possessing near-theoretical strength. Rational design of frameworks remains challenging below 50 nm because of limited methods to arrange small elements into complex architectures. Here, we fabricate silica frameworks with ~4- to 20-nm-thick elements using self-assembly and silica templating of DNA origami nanolattices and perform in situ micro-compression testing to examine the mechanical properties. We observe strong effects of lattice dimensions on yield strength (σ $\mathcal{y}$ ) and failure mode. Silica nanolattices are found to exhibit yield strengths higher than those of any known engineering materials with similar mass density. The robust coordination of the nanothin and strong silica elements leads to the combination of lightweight and high-strength framework materials offering an effective strategy for the fabrication of nanoarchitected materials with superior mechanical properties.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Long-Life, Ultrahigh-Nickel Cathodes with Excellent Air Storage Stability for High-Energy Density Lithium-Based Batteries

With increased energy density and cost advantage, ultrahigh-nickel layered oxides (LiNi x M 1-x O 2 , x = 0.9 - 1.0) are becoming front-runner as cathodes for next-generation lithium-based batteries, yet their commercialization is blocked both by severe capacity fade and exponentially aggravated air degradation. Thus, it is imperative to find effective solutions to address these issues simultaneously. Here, a significant enhancement in both the cycling and air storage stability of the ultrahigh-Ni cathode LiNi 0.94 Co 0.06 O 2 is achieved via a distinctive phosphoric acid treatment strategy. The modified cathode displays remarkably improved capacity retention (from 36 % to 80 % after 1,000 cycles) and rate capability (from 0 to 105 mA h g -1 at 30C rate) in pouch cells. Impressively, the modified cathode, after air storage for 450 days, maintains the morphology and 92% of the initial capacity of the fresh sample with excellent cyclability. Comprehensive interphase and structural analyses reveal that the enhanced electrochemical performance is due to a highly stabilized electrode/electrolyte interphase that suppresses electrode corrosion and lattice reconstruction. The excellent air stability results from an adsorption-buffering effect enabled by phosphoric acid to air attack. Finally, the study demonstrates an engineering pathway to improve the cycling and air stability, facilitating the practical viability of high-capacity, affordable, ultrahigh-Ni cathodes in lithium-based batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Anisotropic 2D excitons unveiled in organic-inorganic quantum wells

Here we report that two-dimensional (2D) excitons arise from electron-hole confinement along one spatial dimension. Such excitations are often described in terms of Frenkel or Wannier limits according to the degree of exciton spatial localization and the surrounding dielectric environment. In hybrid material systems, such as the 2D perovskites, the complex underlying interactions lead to excitons of an intermediate nature, whose description lies somewhere between the two limits, and a better physical description is needed. Here, we explore the photophysics of a tuneable materials platform where covalently bonded metal-chalcogenide layers are spaced by organic ligands that provide confinement barriers for charge carriers in the inorganic layer. We consider self-assembled, layered bulk silver benzeneselenolate, [AgSePh] ∞ , and use a combination of transient absorption spectroscopy and ab initio GW plus Bethe-Salpeter equation calculations. We demonstrate that in this non-polar dielectric environment, strongly anisotropic excitons dominate the optical transitions of [AgSePh] ∞ . We find that the transient absorption measurements at room temperature can be understood in terms of low-lying excitons confined to the AgSe planes with in-plane anisotropy, featuring anisotropic absorption and emission. Finally, we present a pathway to control the exciton behaviour by changing the chalcogen in the material lattice. Our studies unveil unexpected excitonic anisotropies in an unexplored class of tuneable, yet air-stable, hybrid quantum wells, offering design principles for the engineering of an ordered, yet complex dielectric environment and its effect on the excitonic phenomena in such emerging materials.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Grain boundary engineering for additive manufacturing

In one embodiment, a method of manufacturing a metal part using a laser or electron beam during a powder bed additive manufacturing process includes melting each of a number of layers of metal powder of the metal part with an effective amount of energy using the laser or electron beam to form the metal part such that at least one or more portions of the metal part have a critical amount of residual strain. The method also includes performing a heat treatment on the metal part that transforms the residual strain into substantially distributed coincidence site lattice (CSL) grain boundaries, low angle grain boundaries, or both in the metal part.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Anisotropic Exciton Transport in a Lamellar CsPbBr 3 Nanocrystal Superlattice

Colloidal self-assembly is one strategy for engineering anisotropic properties into otherwise isotropic materials. In this work, we demonstrate anisotropic exciton transport in an A 2 B-type superlattice containing columns of 5.3 nm CsPbBr 3 nanocubes assembled into a hexagonal lattice around 6.5 nm LaF 3 nanodisks. Using transient photoluminescence microscopy, we determined that the exciton diffusivity along the fast axis of the superlattice is more than twice as large as that along the slow axis at T = 5 K, but that anisotropy is greatly suppressed at room temperature. Calculations of the diffusivity anisotropy ratio based on Förster theory overestimate the measured values, highlighting the limitations of this theory in completely describing exciton transport. Overall, our results demonstrate how self-assembly of colloidal nanocrystals can be used to engineer directional energy transport, and raise more questions about the microscopic nature of dipole coupling in CsPbBr 3 NC superlattices.

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

An Unbalanced Battle in Excellence: Revealing Effect of Ni/Co Occupancy on Water Splitting and Oxygen Reduction Reactions in Triple–Conducting Oxides for Protonic Ceramic Electrochemical Cells

Porous electrodes that conduct electrons, protons, and oxygen ions with dramatically expanded catalytic active sites can replace conventional electrodes with sluggish kinetics in protonic ceramic electrochemical cells. In this work, a strategy is utilized to promote triple conduction by facilitating proton conduction in praseodymium cobaltite perovskite through engineering non-equivalent B-site Ni/Co occupancy. Surface infrared spectroscopy is used to study the dehydration behavior, which proves the existence of protons in the perovskite lattice. The proton mobility and proton stability are investigated by hydrogen/deuterium (H/D) isotope exchange and temperature-programmed desorption. It is observed that the increased nickel replacement on the B-site has a positive impact on proton defect stability, catalytic activity, and electrochemical performance. This doping strategy is demonstrated to be a promising pathway to increase catalytic activity toward the oxygen reduction and water splitting reactions. The chosen PrNi 0.7 Co 0.3 O 3–δ oxygen electrode demonstrates excellent full-cell performance with high electrolysis current density of –1.48 A cm –2 at 1.3 V and a peak fuel-cell power density of 0.95 W cm –2 at 600 °C and also enables lower-temperature operations down to 350 °C, and superior long-term durability.

08 HYDROGEN↗
DOE OSTI2025

Directing Polymorphism of Colloid Crystals Using Conformational Entropy of Polymer Chains

Controlling the polytypes of close-packed structures of spherical colloids is still a challenging problem despite their wide occurrence. Here, in this work, we show that systematic engineering of the polytype structures of close-packed colloids is possible by using the conformational entropy of polymer chains confined in the interstitial space of colloid crystals. Our interstitial space analysis shows that the hexagonal close-packed (HCP) structures offer larger local interstitial space domains, and the structure director chains in favor of HCP counteract the entropic advantages of the face-centered cubic (FCC) lattices. Using model block copolymer colloids and the known lattice entropy of FCC, a proportionality parameter, β CP = 1.91 × 10 –3 ± 3.67 × 10 –4 , for quantifying the conformational entropy contribution toward HCP structures is extracted. This work demonstrates that the interstitial space of colloid crystals serves as a new structure engineering tool for the self-assembly of colloids.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Resonant ultrasound spectroscopy measurement and modeling of additively manufactured octet truss lattice cubes

In this work, the elastic characteristics of additively manufactured Ti-5553 octet truss lattice cubes were examined using resonant ultrasound spectroscopy (RUS) techniques and correlated to X-ray computed tomography measurements of strut continuity. RUS models and measurements identified an outlier lattice possessing lower effective modulus despite larger effective density. Here, experimental measurements of density and effective Young's modulus were treated as input parameters in a homogenous anisotropic continuum model. The continuum model exhibited good agreement with experimental RUS measurements, thus confirming the potential for a simplified approximation of the octet truss lattice.

42 ENGINEERING↗
DOE OSTI2020

Driven-dissipative quantum mechanics on a lattice: Simulating a fermionic reservoir on a quantum computer

The driven-dissipative many-body problem remains one of the most challenging unsolved problems in quantum mechanics. The advent of quantum computers may provide a unique platform for efficiently simulating such driven-dissipative systems. But, there are many choices for how one can engineer the reservoir. One can simply employ ancilla qubits to act as a reservoir and then digitally simulate them via algorithmic cooling. A more attractive approach, which allows one to simulate an infinite reservoir, is to integrate out the bath degrees of freedom and describe the driven-dissipative system via a master equation, that can also be simulated on a quantum computer. In this work, we consider the particular case of noninteracting electrons on a lattice driven by an electric field and coupled to a fermionic thermostat. Then, we provide two different quantum circuits: the first one reconstructs the full dynamics of the system using Trotter steps, while the second one dissipatively prepares the final nonequilibrium steady state in a single step. We run both circuits on the IBM quantum experience. For circuit (i), we achieved up to five Trotter steps. When partial resets become available on quantum computers, we expect that the maximum simulation time can be significantly increased. Lastly, the methods developed here suggest generalizations that can be applied to simulating interacting driven-dissipative systems.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Chiral Topological Surface States on a Finite Square Photonic Crystal Bounded by Air

Chiral, topologically protected, photonic surface states can be found at the boundary between gyrotropic photonic crystals where a changing magnetic field induces different topology across the interface. Typically, photonic crystals with either a suitable band structure on both sides of the interface to provide a band gap and evanescent decay of the surface states away from the interface, or an outer layer with engineered material properties is required. In this paper, we show the emergence of topological, unidirectional surface states at the termination of finite gyrotropic photonic crystals with a simple square lattice and C 4 rotational symmetry bounded by a vacuum, eliminating the need for an outside layer to enable chiral surface modes. Here, we start from an infinite, time-reversal-symmetry-breaking photonic crystal with a band gap associated with bands with nonzero Chern numbers, different from all-zero Chern numbers in air. We then modify the photonic crystal to move this band gap below the light line, while maintaining the Chern-number discontinuities. Band-structure calculations for a supercell approximating a photonic crystal finite in the direction normal to the surface demonstrate the existence, dispersion, and chirality of the surface mode. Extensive direct scattering calculations for a point source and spatial Fourier analysis further reveal a unidirectional free-space topological surface state, which propagates counterclockwise around the surface of a finite photonic crystal, providing a nearly foolproof way to cross-check the surface-mode band structure unaffected by backscattering from local defects. Additionally, scattering simulations allow an independent characterization of the state dispersion and unveil the robustness of the topological plasmonic mode propagation around the 90° bends of the structure, being due to only radiation leakage. In contrast to buried topological surface states, the observed surface modes at the photonic crystal–air interface have the advantage of being accessible to the outside world, allowing one to take advantage of the defect-tolerant backscattering-free surface modes to engineer emission from photonic crystal surfaces into arbitrary free-space beam shapes and directions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Micropolar deep material network

This study extends the Deep Material Network (DMN), a physics-informed machine learning framework, to predict the homogenized mechanical response of composite materials with micropolar (Cosserat-type) constitutive behavior. This extension incorporates microstructure-dependent size effects, enabling accurate, efficient, and size-aware predictions for composites with complex internal architectures. While traditional, direct numerical simulation micropolar models effectively capture size effects by introducing extra local degrees of freedom, they bring significant computational challenges, particularly for multiscale analyses relevant to engineering applications. The micropolar DMN developed in this paper achieves high accuracy while significantly reducing computation time compared to micropolar direct numerical simulations. This advancement enables multiscale analyses and parameter studies that were previously impractical, such as high-cycle fatigue simulations and comprehensive investigations of internal length scale effects notably in size-dependent plastic response and the optimization of lattice structures. By uniting microstructure-sensitive modeling, physics-driven learning, and scalable surrogate modeling, the micropolar DMN paves the way for accelerated material design, large-scale parametric studies, and the reliable incorporation of size-dependent effects across a wide range of engineering applications, including optimization and next-generation composite design.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Cooperative Education

Los Alamos National Laboratory (LANL) is a multidisciplinary national laboratory that conducts research and development in national security, engineering, materials science, computational modeling, and advanced manufacturing. The laboratory develops innovative technologies to address complex scientific and engineering challenges. This project focuses on the development and evaluation of high-performance absorbing structures through computational design, simulation, and engineering analysis. Absorbing structures are used in applications where damage mitigation, structural protection, and material efficiency are critical performance requirements. The increasing demand for lightweight, high-strength, and highly efficient structural systems has created a need for improved design methodologies capable of maximizing absorption while minimizing weight and material usage. The project utilizes advanced engineering software, including 3D CAD software and FEA, to generate and optimize structural concepts. Computational simulations are performed to evaluate structural behavior under loading conditions, while mathematical analyses are conducted using Python-based tools as well as established analytical equations from material and structural mechanics. The project benefits LANL by supporting the development of advanced design methodologies and improving the understanding of material and structural performance. During the internship term, a significant portion of the design development, simulation, and data analysis activities will be completed. Success of the project depends on collaboration among engineering mentors and technical staff members. Work will be conducted at Los Alamos National Laboratory using laboratory computing resources and engineering software.

42 ENGINEERING↗
DOE OSTI2025

Position-Dependent Neutron Time-of-Flight Deviation at VULCAN Diffractometer

In neutron diffraction, it is critical to precisely measure the lattice spacing, as it is an indicator of a material’s physical characteristics, such as lattice strain, thermal expansion, and phase structures. In time-of-flight (TOF) measurements, the lattice spacing is determined by the recorded TOF from a well-calibrated instrument. However, changes in neutron time-of-flight are sensitive to many factors, such as the alignment of instrument optics, temperature, sample positions, sample dimensions, internal strains, and chemical or physical heterogeneities at the grain level. At VULCAN (SNS, ORNL), which is a high-flux engineering neutron diffractometer, we used a 1-mm-diameter diamond powder sample to scan for changes in TOF by measuring d-spacing values at different sample positions under several configurations. The 2D map of the TOF deviation or d-spacing deviation, in terms of lattice shift/lattice strain, is reported. The change in TOF is dependent on the scanned location in the beam as well as on detector locations. The results are informative for experimental planning, data interpretation, and future instrument design.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Revealing the Hidden Third Dimension of Point Defects in Two-Dimensional MXenes

Point defects govern many important functional properties of two-dimensional (2D) materials. However, resolving the three-dimensional (3D) arrangement of these defects in multi-layer 2D materials remains a fundamental challenge, hindering rational defect engineering. Here, we overcome this limitation using an artificial intelligence-guided electron microscopy workflow to map the 3D topology and clustering of atomic vacancies in Ti3C2TX MXene. Our approach reconstructs the 3D coordinates of vacancies across hundreds of thousands of lattice sites, generating robust statistical insight into their distribution that can be correlated with specific synthesis pathways. This large-scale data enables us to classify a hierarchy of defect structures-from isolated vacancies to nanopores-revealing their preferred formation and interaction mechanisms, as corroborated by molecular dynamics simulations. This work provides a generalizable framework for understanding and ultimately controlling point defects across large volumes, paving the way for the rational design of defect-engineered functional 2D materials.

2D materials↗
DOE OSTI2021

Interface Carriers and Enhanced Electron-Phonon Coupling Effect in Al 2 O 3 /TiO 2 Heterostructure Revealed by Resonant Inelastic Soft X-Ray Scattering

The electronic structure and the electron-phonon couplings in a novel mass-production-compatible Al 2 O 3 /TiO 2 2D electron system (2DES) are investigated using resonant inelastic soft X-ray scattering. The experimental data from the samples of various TiO 2 thicknesses unequivocally show that the Ti 3+ state indeed exists at the deep interface to serve as an n-type dopant for the 2DES. Here, the electronic structure of Ti 3+ species is scrutinized as entirely separated from that of the Ti 4+ host lattice. Furthermore, features of sub-eV energy loss phonon modes are clearly observed, indicating substantial electron-phonon coupling effects. Such low energy loss features are enhanced in thinner TiO 2 samples, implying that polaronic local lattice deformation is enhanced due to the presence of Ti 3+ . These findings suggest that the 2DES properties can be controlled via well-established TiO 2 engineering, thereby enthroning the binary oxide heterostructure as a promising candidate for 2DES device applications.

2D electron gas↗
DOE OSTI2025

First-principles elucidation of defect-mediated Li transport in hexagonal boron nitride

Hexagonal boron nitride (hBN) is a promising candidate as a protective membrane or separator in Li-ion and Li–S batteries, given its excellent chemical stability, mechanical robustness, and high thermal conductivity. In addition, hBN can be functionalized by introducing defects and dopants, or be directly integrated into other active components of batteries, which further augments its appeal to the field. Here, we use first-principles simulations to evaluate the role of atomic defects in hBN in regulating the Li-ion diffusion mechanism and associated kinetics. Specifically, the following four distinct types of vacancy defects are considered: isolated single B and N vacancies, a B–N vacancy pair, and a B 3 N vacancy cluster. It is found that these defect sites generally favor Li intercalation and out-of-plane diffusion but slow down in-plane Li-ion diffusion due to a strong Li trapping effect at the defect sites. Such a trapping effect is, however, highly local such that it does not necessarily affect the overall Li-ion conductivity in defected hBN layers. The present systematic evaluation of the impact of atomic defects on Li ion migration and accompanied charge analysis of hBN lattice in response to Li-ion diffusion provide a mechanistic understanding of Li-ion transport behavior in defected hBN and highlight the potential of defect engineering to achieve optimal material performance.

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

Photo-printing of faceted DNA patchy particles

Patchy particles with shape complementarity can serve as building blocks for assembling colloidal superstructures. Alternatively, encoding information on patches using DNA can direct assembly into a variety of crystalline or other preprogrammed structures. Here, we present a tool where DNA is used both to engineer shape and to encode information on colloidal particles. Two reactive oil emulsions with different but complementary DNA (cDNA) brushes are assembled into CsCl-like crystalline lattices. The DNA brushes are recruited to and ultimately localized at the junctions between neighboring droplets, which gives rise to DNA-encoded faceted patches. The emulsions are then solidified by ultraviolet (UV) polymerization, producing faceted patchy particles. The facet size and DNA distribution are determined by the balance between the DNA binding energy and the elastic deformation energy of droplets. This method leads to a variety of new patchy particles with directional interactions in scalable quantities.

59 BASIC BIOLOGICAL SCIENCES↗