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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Design for Recycling Principles Applicable to Selected Clean Energy Technologies: Crystalline-Silicon Photovoltaic Modules, Electric Vehicle Batteries, and Wind Turbine Blades

Abstract The global growth of clean energy technology deployment will be followed by parallel growth in end-of-life (EOL) products, bringing both challenges and opportunities. Cumulatively, by 2050, estimates project 78 million tonnes of raw materials embodied in the mass of EOL photovoltaic (PV) modules, 12 billion tonnes of wind turbine blades, and by 2030, 11 million tonnes of lithium-ion batteries. Owing partly to concern that the projected growth of these technologies could become constrained by raw material availability, processes for recycling them at EOL continue to be developed. However, none of these technologies are typically designed with recycling in mind, and all of them present challenges to efficient recycling. This article synthesizes and extends design for recycling (DfR) principles based on a review of published industrial and academic best practices as well as consultation with experts in the field. Specific principles developed herein apply to crystalline-silicon PV modules, batteries like those used in electric vehicles, and wind turbine blades, while a set of broader principles applies to all three of these technologies and potentially others. These principles are meant to be useful for stakeholders—such as research and development managers, analysts, and policymakers—in informing and promoting decisions that facilitate DfR and, ultimately, increase recycling rates as a way to enhance the circularity of the clean energy economy. The article also discusses some commercial implications of DfR. Graphical Abstract

36 MATERIALS SCIENCE↗
DOE OSTI2025

Effect of Crystallinity on Polymer Chain Compression in Polyethylene Dynamically Loaded with In-Situ X-Ray Diffraction

Abstract Polyethylene (PE) is a polymer widely used in commercial applications, where the properties of PE can be altered based on the molecular conformation. In this study, shock compression experiments with in-situ x-ray diffraction were conducted on two conformations of PE– low density polyethylene (LDPE) and ultra-high molecular weight polyethylene (UHMWPE). Encouragingly, X-ray diffraction patterns were easily observed in LDPE, which is only 25% crystalline. In agreement with a previous study on HDPE, LDPE exhibited a phase transition at 7.7 GPa. Lower pressure experiments on UHMWPE and LDPE exhibited polymer chain compression, but no occurrence of a phase transition.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Helium effects on the surface and subsurface evolutions in single-crystalline tungsten

Tungsten (W) has been perceived as one of the most promising plasma facing materials (PFMs) for future fusion reactors. In the past decade, its behavior under irradiation and helium (He) plasma interaction has been extensively studied. However, some key knowledge gaps still exist, such as the influence of crystallographic orientation on the surface and subsurface evolutions. In this work, we focus on the He ion-beam irradiation damage effects in mirror-polished single-crystalline W samples with three different surface planes of {100}, {110} and {111}. Irradiation was performed at room temperature using 40 keV He+ to a fluence of 1 × 10 16 /cm 2 , followed by thermal desorption spectroscopy (TDS) up to ~1920 K. The microstructures of He-irradiated W before and after TDS heat treatment were characterized by scanning and transmission electron microscopy. Subsurface He bubbles were imaged in all irradiated samples, but newly formed <111>-oriented surface grains and surface blisters were only observed in W {100} and {110} starting orientations. These results reveal that radiation damage, He thermal desorption, and surface/subsurface evolution are all strongly dependent on crystallographic orientation. Underlying physical mechanisms are discussed based on ion channeling effects, He-vacancy interactions, and surface diffusion. In conclusion, these findings provide new insights into He effects in W.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Athermal annealing of pre-existing defects in crystalline silicon

Systematic investigations of electronic energy loss (S e ) effects on pre-existing defects in crystalline silicon (Si) are crucial to provide reliance on the use of ionizing irradiation to anneal pre-existing defects, leading to successful implementation of this technology in the fabrication of Si-based devices. In this regard, the S e effects on nonequilibrium defect evolution in pre-damaged Si single crystals at 300 K has been investigated using intermediate-energy ions (12 MeV O and Si ions) that interact with the pre-damaged surface layers of Si mainly by ionization, except at the end of their range where the nuclear energy loss (S n ) is no longer negligible. Furthermore, under these irradiation conditions, experimental results and molecular dynamics simulations have revealed that pre-existing disorder in Si can be almost fully annealed by subsequent irradiation with intermediate-energy incident ions with S e values as low as 1.5–3.0 keV/nm. Selective annealing of pre-existing defect levels in Si at room temperature can be considered as an effective strategy to mediate the transient enhanced diffusion of dopants in Si. This approach is more desirable than the regular thermal annealing, which is not compatible with the processing requirements that fall below the typical thermal budget.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Bulk-scale stress–strain hysteresis in layered crystalline solids: A study of graphite and Ti 3 SiC 2

Polycrystalline graphite and the MAX phase Ti 3 SiC 2 are layered crystalline solids with similar deformation mechanisms, including basal slip, ripplocation boundaries (RBs), kink boundaries (KBs), and cracking. The interplay of these mechanisms, notably in energy dissipation, has been much discussed in the past twenty-five years. This study builds upon previous work, investigating deformation with a renewed emphasis on the bulk-scale and given recent findings concerning RBs. Our investigation compares the evolution of energy dissipation, nonlinear recoverable and irrecoverable strain, and damage upon increasing stress for graphite and Ti 3 SiC 2 . Benitez et al.’s (2016) methodology of compressive cyclic loading and post-mortem electron backscatter diffraction (EBSD) to assess the prevalence of kinking based on low-angle grain boundaries (LAGBs) was used. Strains were measured with digital image correlation and EBSD was conducted on Ti 3 SiC 2 leveraging dictionary indexing, which was necessary herein to identify LAGBs accurately. The stress–strain stages of Ti 3 SiC 2 agree with literature on Ti 2 AlC. Damage and energy dissipation were more accelerated in graphite. No significant difference was observed in the fraction of LAGBs between pristine and unloaded Ti 3 SiC 2 . Trends observed and EBSD evidence that KBs were not dominant suggest that RBs are the primary dissipator of energy in both materials.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Amorphous-crystalline transition-driven synthesis of Co single-atom catalysts on MoO 3 for enhanced hydrogen evolution in acidic and alkaline media

Single atom catalysts (SACs) dispersed in metal oxide supports offer not only maximized catalyst utilization but also extended modulation capabilities through interactions between the SA and its support. However, achieving facile preparation and ensuring electrochemical durability of such SACs, particularly for hydrogen evolution reaction (HER) applications, remain formidable challenges. Here, our study addresses these issues by employing an amorphous-to-crystalline phase transition in MoO 3 to synthesize a cobalt (Co) SA catalyst. This method facilitates the production of highly selective SA catalysts at low temperatures and ensures their enhanced stability in HER applications. The Co SA MoO 3 catalyst exhibits superior performance in HER, operating effectively in both acidic and alkaline environments. Significantly, it maintains stable HER activity across these diverse electrolytic conditions. Our Density Functional Theory (DFT) calculations provide insights into the exceptional HER performance of Co SA MoO 3 . These calculations reveal that the strong affinity for hydrogen and water, facilitated by the modulation of the p-band orbitals at specific oxygen sites adjacent to the Co SA, establishes a thermoneutral pathway for HER. This study represents a pivotal advancement, showcasing a highly practical and robust single-atom catalyst, marking a significant stride towards sustainable energy solutions.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Effect of chloride ingress on self-healing recovery of smart cementitious composite incorporating crystalline admixture and MgO expansive agent

Highlights: • Crack closure under wet/dry cycles in chloride solution is higher than the one in distilled water. • Element analysis shows that calcium is vital for crack healing either in water or chloride solution. • AFm is consumed by chloride ion to form Fs, and Fs were decomposed to AH{sub 3} by carbonation. • Soluble reactive silica reacts with calcium hydrate to form C-S-H gel to heal concrete cracks. • Expansion of magnesium hydroxide facilitates crack self-healing by interconnected network. In this study, the effect of chloride environment containing various concentrations of chloride ion (Cl{sup −}) on self-healing performance of pre-cracked cementitious composite containing crystalline admixture (CA) and MgO expansive agent (MEA) was investigated under wet-dry cycles in chloride solutions. The results revealed that the Cl{sup −} changed the mineralogy of self-healing products, and consequently, affected the crack closure ratio and mechanical strength recovery. When self-healing occurred in distilled water, a large amount of ettringite (AFt) were detected, whereas in Cl{sup −} solution, monosulfate (AFm) was consumed by Cl{sup −} to form Friedel's salt (Fs), and then the Fs was decomposed to Al(OH){sub 3}(AH{sub 3}) due to carbonation. During the multiphase conversion process, hydroxide (OH{sup −}) was released into crack solution, therefore the dissolved carbon dioxide (CO{sub 2}) concentration was increased. The carbonation of the crystals formed in cracks was accelerated with the volume expansion, which achieved rapid crack sealing but contributed little to the mechanical performance recovery.

36 MATERIALS SCIENCE↗
DOE OSTI2022

CASM — A software package for first-principles based study of multicomponent crystalline solids

CASM is a software package that enables first-principles based studies of crystalline materials. It has been designed to treat coupled chemical, mechanical, vibrational, and magnetic degrees of freedom to determine ground state and finite temperature properties of crystals. The symmetry of the underlying parent crystal structure is used to enumerate perturbations of the parent crystal structure and generate derivative structures which can be input to first-principles calculations in order to explore the ground state energy landscape. CASM algorithmically constructs cluster expansions that fully couple discrete and continuous degrees of freedom, and generates highly efficient code to evaluate the cluster expansion basis functions. Widely used machine learning methods are integrated for fitting expansion coefficients to first-principle calculations. The fully parameterized cluster expansions can be combined with (kinetic) Monte Carlo methods to calculate finite temperature thermodynamic and kinetic properties. CASM Alloy Manager identifies distinct parent crystal structures in an alloy system, creating individual projects for each, and integrating the results. The integrated infrastructure facilitates the linkage between first-principles statistical mechanics predictions with higher length scale computational methods, such as phase field simulations. In conclusion, CASM projects are designed to be easy to share in repositories, to re-use, and to extend to include additional chemical species or types of degrees of freedom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Nanotomographic observation and statistical analysis of overcharging induced cracks in LiCoO 2 single crystalline particles

Particle fracture represents an important mode of battery electrode degradation. Extensive cracking occurs in the layered oxide cathodes of lithium-ion rechargeable batteries when they are charged beyond safe operational voltages. In this paper, we analyze the morphology and distribution of cracks in over 100 overcharged LiCoO 2 (LCO) single-crystalline particles imaged via X-ray nanotomography. Herein, we observe a strong particle size dependence in both nucleation and growth of cracks, with percentage of cracked particles, crack size, and crack surface area per unit volume all increasing significantly with particle volume. Increasing the cutoff voltage above 4.6V is found to trigger much more pronounced crack growth, which we attribute to the large misfit stress caused by the H1-3 to O1 phase transition. This study offers valuable statistical insights into the fracture behavior of layered oxide cathodes and reveals the importance of particle size control on electromechanical degradation of battery electrodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Quasicrystalline phase and crystalline approximant in Ni–Mn–In Heusler alloy system

Intermetallic compounds and micro-structures in Ni–Mn–In alloy system were investigated with transmission electron microscopy, selected-area and nano-beam electron diffraction, and energy-dispersive x-ray spectroscopy. Together with two types of Heusler phases, a decagonal quasicrystalline phase and a structurally related crystallite were found in the Ni–Mn–In system. As is well-known, most of the decagonal quasicrystals are aluminum-based intermetallic phases. It is interesting to investigate the aluminum-free decagonal quasicrystalline phase as a new member of the quasicrystal family. Structural characterization was carried out on the decagonal quasicrystalline phase and the crystalline approximant in the Ni–Mn–In alloy system.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Understanding the origin of magneto-crystalline anisotropy in pure and Fe/Si substituted SmCo 5

In this paper, we report magneto-crystalline anisotropy of pure and Fe/Si substituted SmCo5. The calculations were performed using the advanced density functional theory (DFT) including onsite electron-electron correlation and spin-orbit coupling. Si substitution substantially reduces both the uniaxial magnetic anisotropy and the magnetic moment. Fe substitution with the selective site, on the other hand, enhances the magnetic moment with a limited chemical stability. The magnetic hardness of the SmCo5 is governed by the Sm 4f localized orbital contribution. The 4f density of states (DOS) becomes flat and split with the substitution of Co (2c) with Si/Fe atoms, except with the Fe substitution at 3 g sites. It is also confirmed that Si substitution favors the thermodynamic stability on contrary to the diminished magnetic and anisotropic effects in SmCo5 at either sites.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Interplay of molten salt and dopants in tuning the performance of single-crystalline LiNiO 2

Single-crystalline layered oxide cathodes have seen great research interest in recent years. Adoption of single-crystal morphology improves mechanical robustness and eliminates intergranular boundaries, improving the chemical stability of the cathode. Furthermore, single-crystal cathodes also suffer from worsened lithium-diffusion kinetics stemming from the significantly increased diffusion path lengths. Sluggish lithiation kinetics induce concentration gradients within the cathode particle during cell operation, resulting in the accumulation of lattice strain, which deteriorates cell performance. Foreign dopants have been shown to greatly improve ion diffusion in many high-Ni layered oxide cathode systems. In particular, we identify Ti and Te as promising dopants to ameliorate the slow diffusion kinetics. We find that doping 1 mol.% Te into single crystal LiNiO 2 greatly improves Li + diffusivity, as determined through galvanostatic intermittent titration technique. Further incorporating 2 mol.% Al and pairing with lithium-metal anode in a localized high concentration electrolyte (LHCE) delivers 206 mA h g -1 at C/3 rate and retains 94% capacity after 100 cycles in Li metal half cells. By addressing kinetically mediated degradation with Te doping, and surface-based degradation with Al and LHCE, the cathode experiences very little polarization and overpotential growth, enabling stable cycling with high accessible capacity.

25 ENERGY STORAGE↗
DOE OSTI2022

Crystalline compounds for remediation of rare-earth fission products: A review

Rare-earth (RE) containing crystals have been investigated as media for the immobilization of RE fission products. During reprocessing of spent nuclear fuels, various fission products including REs, alkalis, and alkaline earths are found after the extraction of actinides. One viable option to immobilize the RE fission products is to incorporate them into chemically durable crystalline phases in specific waste forms. This study summarizes the crystal structures and synthesis methods of six RE-containing compounds that have applications in remediation of RE fission products. These compounds include oxyapatite [Ca2RE8(SiO4)6O2], oxychloride [REOCl], borosilicate [RE3BSi2O10], pyrochlore [RE2A2O7], monazite [REPO4], and perovskite [REAO3] where A denotes transitional metals. This review provides an overview of literature on the usage of these six compounds for immobilizing RE fission products and summarizes different synthesis methods for producing these compounds. Comparisons of structural parameters with different REs in each compound are also discussed.

rare-earth oxychloride, rare-earth oxyapatite, rar↗
DOE OSTI2022

Enabling a novel approach to a controlled fabrication of 1D crystalline nanowires on suspended microstructures of arbitrary geometries using two direct-writing technologies

Recent progresses in additive manufacturing have inspired new technologies, such as direct laser writing technique, based on two-photon polymerization (2 PP), which complements and further enriches the nanofabrication tools portfolio. Here, we combine 2 PP and our mask-free scanning probe assisted ‘direct-write patterning’ (DWP) method to allow for: a) the fabrication of micro-bridge structures with sub-micrometer resolution, b) selective synthesis of crystalline ZnO nanowires at predefined locations, respectively. This synergistic approach enables cantilever probe patterning of catalysts directly on suspended micro-bridges for in-situ CVD growth of nanoscale material, in a templated manner. The study reported here represents the first proof-of-concept experiments demonstrating versatile and scalable methodology, which can be applied and straightforwardly extended to grow a variety of other nanomaterials, in a controlled and selective fashion, on freestanding micro/nanoscale structures, whose size and geometry can be conveniently varied via templating of sacrificial 2 PP polymeric scaffolds. Furthermore, the demonstration of the possibility to integrate this new approach with the conventional lithography techniques provides a step forward to the development of the novel class of hybrid polymer-silicon-1D or -2D materials, and systems. The quality of the produced ZnO nanowire assemblies was assessed using several physical characterization methods.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Larger than uncorrelated vacancy diffusion contributions in chemically disordered crystalline materials

Arising from a variational approach to compute diffusion coefficients, we introduce “superkinetic kinosons”, which are contributions to the diffusion flux of mobile defects and atomic species by single jump mechanisms that can exceed their uncorrelated values. In vacancy-mediated diffusion in crystalline random and high entropy materials, these contributions primarily arise from intermittent jumps of slow moving atoms that remove the vacancy out of correlation traps and enable a quantification of such effects on the diffusion coefficients. They can be significant contributors to diffusion, even when faster moving atoms have infinite percolation networks. Furthermore, their existence and importance provide fundamental insights about underlying aspects of vacancy diffusion such as formation of localized correlation traps and deviation of vacancy diffusion from percolation behavior.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Origin of the Tunable Carrier Selectivity of Atomic-Layer-Deposited TiOx Nanolayers in Crystalline Silicon Colar Cells

Titanium oxide (TiOx) nanolayers grown by atomic layer deposition are investigated with respect to their application as carrier selective contacts for crystalline silicon (c-Si) solar cells. Although TiOx is known to act as an electron contact, in this work the selectivity of TiOx layers is found to be widely tunable from electron to hole selective depending on deposition conditions, post-deposition treatments, and work function of the metal electrode used. Using TiOx and an intrinsic hydrogenated amorphous silicon buffer layer, solar cell test structure exhibiting open-circuit voltages (Voc) as high as 720 and 650 mV are shown for electron and hole selective contacts, respectively. Surface photovoltage and capacitance-voltage measurements reveal that carrier selectivity is correlated with the amount of c-Si band bending induced by TiOx, which are governed not only by the effective work function difference at the Si/TiOx interface, but also by the negative fixed charge present in the TiOx layer. This new finding is in contrast to the previous model for carrier transport where selectivity is determined only by the asymmetric band offsets at the Si/contact interface. It highlights the influence of induced band bending to produce carrier depletion/inversion conditions, and the importance of its selectivity effect in a c-Si absorber.

14 SOLAR ENERGY↗
DOE OSTI2023

Spin diffusion in the Phosphorus-31 NMR relaxation in a layered crystalline α-Sn(IV) phosphate contaminated by paramagnetic impurities

The study of a layered crystalline Sn(IV) phosphate by solid-state NMR has demonstrated that the 31 P T 1 relaxation of phosphate groups, dependent on spinning rate is completely controlled by the limited spin diffusion to paramagnetic ions found by EPR. The spin-diffusion constant, D(SD), was estimated as 2.04 10 –14 cm 2 s –1 . Finally, the conclusion was supported by the 31 P T 1 time measurements in zirconium phosphate 1–1, also showing paramagnetic ions and in diamagnetic compound (NH 4 ) 2 HPO 4 .

1H MAS NMR↗
DOE OSTI2023

Exploring the interfacial structure and crystallinity for direct growth of Mn 3 Sn(0001) on sapphire (0001) by molecular beam epitaxy

The Kagome antiferromagnet Mn 3 Sn has garnered a lot of attention due to the presence of interesting properties such as anomalous Hall effects and Nernst effects. Until now, few papers have been reported to grow using molecular beam epitaxy with a buffer layer or on other substrates. In this paper, we discuss the synthesis of crystalline Mn 3 Sn layers, prepared on Al 2 O 3 (0001) without a buffer layer using molecular beam epitaxy. The growth is monitored in-situ using reflection high energy electron diffraction and measured ex-situ using X-ray diffraction, Rutherford back-scattering, and cross-sectional scanning transmission electron microscopy. The samples were deposited at 524 ± 5 °C, with an Mn: Sn atomic flux ratio of 3.2:1 for 90 minutes. Orientation relationships between the Mn 3 Sn films and the sapphire substrates are determined from in-plane and out-of-plane measurements. Our analysis indicates that the resulting film is predominantly c−plane oriented. Lastly, the samples prepared in this way were found to be discontiguous, showing a 3-dimensional morphology. According to first-principles calculations, the Mn 3 Sn exhibits a displaced Kagome structure in the very first stages of growth, for 2ML and 4ML growth on Al 2 O 3 (0001). This result is corroborated by calculating the surface formation energies and explains the observed RHEED patterns.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗