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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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Manufacturing and characterization of continuous fiber-reinforced thermoplastic tape overmolded long fiber thermoplastic

Light-weight construction, design freedom, integration of functions, and compelling cost element are desired by Original Equipment Manufacturers (OEMs) and their suppliers. The emergence of overmolding of continuous-discontinuous reinforcement enables design freedom and ability to tailor stiffness, strength, and damage tolerance for structural applications. In this work, long fiber thermoplastics (LFT) are overmolded with continuous fiber-reinforced thermoplastic (CFRTP) tape are combined using extrusion compression molding process to evaluate the structural performance. The CFRTP tape overmolded LFT samples were characterized using nondestructive and destructive techniques to track fiber alignment, fiber distribution, manufacturing defects, interfacial bonding of the tape – LFT and effect of CFRTP tape on LFT. Mode 1 fracture toughness, G 1c for tape overmolded LFT was higher by 25–30% compared to literature reported G 1c . This response was attributed to excellent fiber distribution, good fiber wetting, and absence of voids at the interface. Three-point bend test indicated that CFRTP tape overmolded LFT composites were better able to resist damage under the bending load compared to constituent LFT composite. Flexural strength of the overmolded composite was higher by 119–142%, and modulus higher by 77–65% compared to constituent LFT composite. Simulated flexural results accurately represents the mechanical behavior of composites. Here, the penetration energy of tape overmolded LFT composites determined by LVI test was in the range of 27.66–30.15 J, which is significantly higher than constituent LFT composite, 7.76 J. CFRTP tape overmolded LFT composite exhibits progressive fiber fracture, matrix cracking, and interfacial debonding failure, whereas, constituent LFT composite showed catastrophic fiber fracture.

42 ENGINEERING↗
DOE OSTI2023

Synergizing Electron and Heat Flows in Photocatalyst for Direct Conversion of Captured CO 2

Abstract We report a ternary hybrid photocatalyst architecture with tailored interfaces that boost the utilization of solar energy for photochemical CO 2 reduction by synergizing electron and heat flows in the photocatalyst. The photocatalyst comprises cobalt phthalocyanine (CoPc) molecules assembled on multiwalled carbon nanotubes (CNTs) that are decorated with nearly monodispersed cadmium sulfide quantum dots (CdS QDs). The CdS QDs absorb visible light and generate electron‐hole pairs. The CNTs rapidly transfer the photogenerated electrons from CdS to CoPc. The CoPc molecules then selectively reduce CO 2 to CO. The interfacial dynamics and catalytic behavior are clearly revealed by time‐resolved and in situ vibrational spectroscopies. In addition to serving as electron highways, the black body property of the CNT component can create local photothermal heating to activate amine‐captured CO 2 , namely carbamates, for direct photochemical conversion without additional energy input.

Choi, Chungseok↗
DOE OSTI2023

2023 roadmap for potassium-ion batteries

Abstract The heavy reliance of lithium-ion batteries (LIBs) has caused rising concerns on the sustainability of lithium and transition metal and the ethic issue around mining practice. Developing alternative energy storage technologies beyond lithium has become a prominent slice of global energy research portfolio. The alternative technologies play a vital role in shaping the future landscape of energy storage, from electrified mobility to the efficient utilization of renewable energies and further to large-scale stationary energy storage. Potassium-ion batteries (PIBs) are a promising alternative given its chemical and economic benefits, making a strong competitor to LIBs and sodium-ion batteries for different applications. However, many are unknown regarding potassium storage processes in materials and how it differs from lithium and sodium and understanding of solid–liquid interfacial chemistry is massively insufficient in PIBs. Therefore, there remain outstanding issues to advance the commercial prospects of the PIB technology. This Roadmap highlights the up-to-date scientific and technological advances and the insights into solving challenging issues to accelerate the development of PIBs. We hope this Roadmap aids the wider PIB research community and provides a cross-referencing to other beyond lithium energy storage technologies in the fast-pacing research landscape.

Xu, Yang (ORCID:0000000301776348)↗
DOE OSTI2026

Structural effects of composition tuning in A-site disordered perovskite La0.5Li0.5−xMxTiO3 (M = Na, K) nanorods for fast interfacial transport for solid composite electrolyte design

Polymer-ceramic composite electrolytes (CPE) have emerged as promising replacements for currently used liquid organic electrolytes, which pose as safety hazards, in Li-ion batteries. Limits in conductivity enhancement in CPEs is often attributed to a high resistance for Li-ion transport along the interface due to the incompatibility of the polymer and ceramic phases. A clear understanding of the interfacial structure and how this impacts interfacial Li-ion transport is needed in order to efficiently design a CPE with optimal ionic conductivity. In this study, density functional theory (DFT) calculations, in conjunction with scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS), are used to unveil the bulk and surface structure of La0.5Li0.5−xMxTiO3 (M = Na, K) (LMTO) nanorods, a newly-reported ceramic system with promising applications in CPEs, and the LMTO interactions with the poly(lithium sulfonyl (trifluoromethane sulfonyl)imide methacrylate) (p(MTFSILi)) polymerized ionic liquid. Substitution of lithium for sodium and potassium onto the A-site perovskite lattice is shown to increase the stability of the preferred pseudocubic perovskite phase because of their increased cation size which allows them to reduce the TiO6 octahedral rotations in the bulk and at the surface. STEM and EELS results show that LMTO nanorods with differing compositions have Ti-enriched (110)-oriented surfaces. Increased sodium and potassium compositions in LMTO is also shown using the DFT calculations to weaken the binding of the lithium atom to the MTFSI unit when LiMTFSI is adsorbed to the LMTO surface. This weakening of lithium binding to the polymer at the LMTO interface indicates that the lithium mobility is increased, correlating to an increase in interfacial Li-ion transport. Overall, this work provides insights into how to tune the interfacial interactions between the polymer (p(MTFSI)) and ceramic (LMTO) for optimal CPE design.

Shepard, Lauren B [Pennsylvania State University, ↗
DOE OSTI2024

Operando Freezing Cryogenic Electron Microscopy of Active Battery Materials

Abstract Understanding structural and chemical evolution of battery materials during operation is critical to achieving safe, efficient, and long-lasting energy storage. Cryogenic electron microscopy (cryo-EM) has become a valuable tool in battery characterization, leveraging low temperatures to improve stability of sensitive materials under electron beam irradiation. However, typical cryo-EM sample preparations leave extended time between the electrochemical point of interest and ex situ freezing of samples, during which active structures may relax, degrade, or otherwise evolve. Here, we detail a method for operando freezing cryo-EM to preserve and characterize native electrode and interfacial structures that arise during battery cycling, based on an operando plunge freezer and cold sample removal process. We validate the method on multiple electrode materials and quantify and discuss the freezing rate achieved. Operando freezing cryo-EM can be used to directly visualize transient features that arise at active electrochemical interfaces, to enable deeper understanding of structural evolution and interfacial chemistry in batteries and other electrochemical systems.

25 ENERGY STORAGE↗
DOE OSTI2021

Ab initio metadynamics calculations reveal complex interfacial effects in acetic acid deprotonation dynamics

Acid-base reactions play a central role in solution chemistry, with carboxylic acids being particularly important in atmospheric chemical processes. In this work, we harness metadynamics calculations with Born-Oppenheimer molecular dynamics (BOMD) simulations to understand deprotonation dynamics of acetic acid (CH 3 COOH) in both bulk and air-water interfacial environments. Collective variables are carefully chosen in our well-tempered metadynamics simulations to capture the deprotonation process in various aqueous configurations. Herein, our findings show that the free energy barrier for deprotonation of acetic acid at the air-water interface is lower than in the bulk, in accordance with the available experimental data. Furthermore, our well-tempered metadynamics calculations suggest that the variations in free energy are primarily due to intricate solvation shell effects.

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

Integrated Ion-Exchange Membrane Resin Wafer Assemblies for Aromatic Organic Acid Separations Using Electrodeionization

Aromatic acids, such as p-coumaric acid, are valuable chemical intermediates that are used in the specialty chemical industries because they are precursors to phenylpropanoid compounds. The separation of p-coumaric acid from fermentation broths is a critical step in the biochemical production process and more broadly the circular carbon economy. Electrodeionization (EDI) has been applied toward separations of low-carbon chain acids, but purifying p-coumaric acid has been challenging due to fouling and irreversible binding with ion-exchange membranes and resins. Here, we report a new membrane wafer assembly (MWA) consisting of laminated ion exchange membranes to porous ionomer-binder resin wafers for EDI. The MWAs in an EDI stack showed a 7-fold increase in p-coumaric acid capture while also using 70% less specific energy consumption when benchmarked against state-of-the-art resin wafer EDI modules. The more efficient p-coumaric acid recovery was ascribed to (i) the 38% reduction in interfacial transport resistance between the membrane and resin wafer and (ii) using imidazolium anion exchange membranes and ionomer binders in the MWA. MD simulations revealed enhanced transport rates for p-coumarate in imidazolium ionomers through π–π interactions. As a result, adopting the new MWA significantly reduced the amount of ion-exchange membranes in EDI and may lead to drastic capital cost savings.

42 ENGINEERING↗
DOE OSTI2024

Tuning the solvation structure with salts for stable sodium-metal batteries

Sodium-metal batteries are an appealing, sustainable, low-cost alternative to lithium metal batteries due to the high abundance and theoretical specific capacity (1,165 mA h g -1 ) of sodium. However, the poor compatibility of the electrolyte with the cathode and anode leads to unstable electrode-electrolyte interphases. Here we introduce the concept of using a salt as a diluent, which enables the use of a single non-flammable solvent, such as trimethyl phosphate. By using sodium nitrate (NaNO 3 ) salt as a model diluent, we report a 1.1 M NaFSI-NaNO 3 -trimethyl phosphate electrolyte that forms a stable interface with sodium-metal anode. In addition, the formation of robust cathode-electrolyte interphases on Na(Ni 0.3 Fe 0.4 Mn 0.3 )O 2 cathode facilitates smooth phase transitions, thus leading to stable cycle life with a capacity retention of 80% over 500 cycles at C/5 rate in Na||Na(Ni 0.3 Fe 0.4 Mn 0.3 )O 2 cells. Further, the work demonstrates a promising approach towards the development of safe, low-cost, sustainable high-performance sodium-metal batteries. Electrolytes with non-flammable solvents are important for the safe operation of sodium-metal batteries. Here the authors report an electrolyte engineering approach, employing salts as a diluent, to enhance interfacial stability and overall safety.

25 ENERGY STORAGE↗
DOE OSTI2025

Trade-offs at the interface

The durability of perovskite solar cells is closely linked to the mechanical adhesion toughness of their interfaces, though some toughening strategies could trigger detrimental chemical reactions. Here, research now shows that this trade-off can be effectively managed through interfacial engineering, informed by innovative mechanical testing.

14 SOLAR ENERGY↗
DOE OSTI2026

Direct electrode-to-electrode regeneration of end-of-life batteries via electrode–electrolyte interphase dissolution

Lithium-ion battery recycling remains constrained by processes that recover metals at the expense of electrode integrity, while even direct recycling typically requires shredding to black mass followed by binder removal, separation, and full electrode refabrication. Here, we introduce direct electrode-to-electrode regeneration (DEER), a simultaneous electrochemical regeneration of used NMC and graphite electrodes from end-of-life batteries in their intact form by dissolving the passivating electrode–electrolyte interphase (EEI). DEER employs 1,3-dimethyl-2-imidazolidinone (DMI), a high donor number solvent that creates a thermodynamic environment favorable for solubilizing redox inactive EEI components. DEER dissolves the thick EEI on both used electrodes while preserving electrode integrity, enabling up to 95% capacity regain and improved cycling stability with a residual LiF-rich interphase. Operando Raman, operando IR, and post-mortem NMR directly track the electrochemically driven dissolution of carbonate-derived EEI species in the used DMI-based recycling electrolyte. Technoeconomic and life-cycle analyses show that DEER reduces the cost of recycled cell manufacturing by 56% relative to pyro- and hydrometallurgy, while lowering energy use and greenhouse gas emissions. Overall, DEER establishes the first validated pathway to directly regenerate and reuse electrodes harvested from truly end-of-life batteries, converting the key interfacial bottleneck into a controllable dissolution process and opening a practical route toward electrode level circularity.

Kim, Kiwon [Cornell Univ., Ithaca, NY (United Stat↗
NASA NTRS1985

Enhanced adhesion of films to semiconductors or metals by high energy bombardment

Films (12) of a metal such as gold or other non-insulator materials are firmly bonded to other non-insulators such as semiconductor substrates (10), suitably silicon or gallium arsenide by irradiating the interface with high energy ions. The process results in improved adhesion without excessive doping and provides a low resistance contact to the semiconductor. Thick layers can be bonded by depositing or doping the interfacial surfaces with fissionable elements or alpha emitters. The process can be utilized to apply very small, low resistance electrodes (78) to light-emitting solid state laser diodes (60) to form a laser device 70.

Tombrello, Thomas A.↗
NASA NTRS2010

A Compendium of Scale Surface Microstructures: Ni(pt)al Coatings Oxidized at 1150 C for 2000 1-h Cycles

The surface structure of scales formed on Ni(Pt)Al coatings was characterized by SEM/EDS/BSE in plan view. Two nominally identical {100} samples of aluminide coated CMSX4 single crystal were oxidized at 1150 C for 2000 1-h cycles and were found to produce somewhat disparate behavior. One sample, with less propensity for coating grain boundary ridge deformation, presented primarily alpha-Al2O3 scale structures, with minimal weight loss and spallation. The original scale structure, still retained over most of the sample, consisted of the classic theta-alpha transformation-induced ridge network structure, with approx. 25 nm crystallographic steps and terraces indicative of surface rearrangement to low energy alumina planes. The scale grain boundary ridges were often decorated with a fine, uniform distribution of (Hf,Ti)O2 particles. Another sample, producing steady state weight losses, exhibited much interfacial spallation and a complex assortment of different structures. Broad areas of interfacial spalling, crystallographically-faceted (Ni,Co)(Al,Cr)2O4 spinel, with an alpha-Al2O3 base scale, were the dominant features. Other regions exhibited nodular spinel grains, with fine or (Ta,Ti)-rich (rutile) particles decorating or interspersed with the spinel. While these features were consistent with a coating that presented more deformation at extruded grain boundaries, the root cause of the different behavior between the duplicate samples could not be conclusively identified.

Smialek, James L.↗
DOE OSTI2022

Effect of Gold Catalyst Surface Morphology on Wetting Behavior and Electrochemical CO 2 Reduction Performance in a Large-Area Zero-Gap Gas Diffusion Electrolyzer

We report catalyst surface area and wetting behavior are key factors in determining the performance of gas diffusion electrode (GDE) electrolyzers for electrochemical CO 2 reduction. In this work, we report the integration of sub-1 μm thick nanoporous gold (npAu) catalyst coatings into a large-area (25 cm 2 ) zero-gap electrolyzer. The npAu coatings were prepared by magnetron sputtering (MS) of thin AgAu alloy films on the microporous carbon layer of a gas diffusion layer (GDL) followed by Ag leaching. Compared to MS Au films of the same thickness, npAu catalyst coatings enable higher Faradaic efficiencies and improved catalyst stability for CO 2 -to-CO reduction with Faradaic efficiencies of up to 88% at 100 mA/cm 2 . For a 800 nm npAu coating, the device level energy efficiency for CO 2 to CO conversion reaches 45% (52% for CO + H 2 ) at 100 mA/cm 2 with a single pass CO 2 conversion efficiency of ~12%. Contact angle measurements reveal that npAu coatings provide a more hydrophobic electrode interface compared to MS Au coatings, suggesting that the more hydrophobic interfacial environment of npAu coatings helps mitigating electrode flooding which is associated with performance deterioration over time.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2023

Lattice Oxygen Redox Reversibility Modulation in Enhancing the Cycling Stability of Li-Rich Cathode Materials

The practical application of lithium-rich layered oxides is prohibited by the drawbacks such as severe capacity and voltage degradation resulting from unstable oxygen redox environment and the accompanied irreversible oxygen release. In this report a facile and effective strategy is proposed to regulate the oxygen redox chemistry via foreign Fe doping and its induced intrinsic transition metal (TM) doping as well as the in situ constructed spinel surface layer. The Fe doping, together with the induced intrinsic TM dual doping, can stabilize the lattice oxygen in the bulk due to the formed stronger Fe—O bond, and restrain the irreversible TM migration and then the undesirable phase transformation. More importantly, thermodynamical energy barrier of oxygen activation is dramatically decreased by the O 2p–Fe 3d charge-transfer, allowing stable oxygen redox activity. And the pre-constructed spinel layer can effectively stabilize the surface lattice oxygen and suppress harmful interfacial side-reactions. Such a simple optimizing method make the modified cathode exhibit a high specific capacity of 298 mAh g -1 at 0.2 C, outstanding cycling stability with a superior capacity and voltage retentions of 92.5% and 90.8%, respectively, after 400 cycles at 1 C. This study provides a new direction for developing advanced Li-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Dilute Regeneration-Driven Membrane Capacitive Deionization of Synthetic Seawater Using Nanopatterned Membranes and Prussian Blue Analog Electrodes

Membrane capacitive deionization (MCDI) offers energy-efficient seawater desalination but is limited at high salinity by membrane resistance and incomplete electrode regeneration. Nanopatterned ion-exchange membranes, dilute regeneration protocols, and Prussian blue analog (PBA)-functionalized electrodes are combined in a flow-by-MCDI cell. Nanopatterned ion-exchange membranes (hexagonal, octagonal, double-ring, rectangular) enhance interfacial ion transport, with hexagonal geometry delivering ≈12.5% greater surface area and the best performance. PBA-functionalized electrodes increase salt adsorption and charge-transfer kinetic rates. The integrated system lowers the area-specific resistance by 45 Ω cm2, resulting in a 500 mV reduction in the cell voltage for a current density of 2 mA cm−2 for a 35 000 ppm NaCl feed. This improves the energy-normalized salt adsorption six fold (64–382 mmol J−1). Low salinity (2000 ppm) and mixed-salt regeneration sustains a ≈39% water recovery and stable performance for at least seven cycles. Overall, combining nanopatterned membranes, which promote confinement-enhanced ion mobility, and PBA electrodes, which enhance salt adsorption, improved the energy efficiency of MCDI.

Hasan, Mahmudul↗
DOE OSTI2022

Mechanical behavior of bimetallic stainless steel and gray cast iron repairs via directed energy deposition additive manufacturing

The utility of gray cast iron in engine components remains tied to the mechanical performance and cost. Repair and remanufacturing of castings offer economical and sustainable benefits; however, high thermal input from traditional fusion-based welding is unable to restore the original mechanical quality owing to brittle microstructures and porosity formed in situ. Directed energy deposition (DED) is an additive manufacturing method that has received considerable interest for repairs owing to the highly controllable nature of the process. Despite this, few works have connected the effect of DED parameters on actual interfacial strength. Consequently, distinct DED parameter combinations were identified to maximize the strength and fatigue life of the repaired cast iron. Further, high speed melt pool imaging and residual stress measurements are provided to aid in the understanding of the metallurgical quality and strength seen in these structures. In general, higher scanning speeds and lower thermal gradients promoted comparable tensile strength to that of the original gray cast iron. The results presented here provide a foundation to tune in the DED process to generate the required mechanical quality as a starting point for future process advancements.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Ni Nanoparticles on CeO 2 (111): Energetics, Electron Transfer, and Structure by Ni Adsorption Calorimetry, Spectroscopies, and Density Functional Theory

The morphology, interfacial bonding energetics and charge transfer of Ni clusters and nanoparticles on slightly-reduced CeO 2-x (111) surfaces at 100 to 300 K have been studied using single crystal adsorption calorimetry (SCAC), low-energy ion scattering spectroscopy (LEIS), Xray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and density functional theory (DFT). The initial heat of adsorption of Ni vapor decreased with the extent of pre-reduction (x) of the CeO 2-x (111), showing that stoichiometric ceria adsorbs Ni more strongly than oxygen vacancies. On CeO 1.95 (111) at 300 K, the heat dropped quickly with coverage in the first 0.1 ML, attributed to nucleation of Ni clusters on stoichiometric steps, followed by the Ni particles spreading onto less favorable terrace sites. At 100 K, the clusters nucleate on terraces due to slower diffusion. Adsorbed Ni monomers are in the +2 oxidation state, and they bind by ~45 kJ/mol more strongly to step sites than terraces. The measured heat of adsorption versus average particle size on terraces is favorably compared to DFT calculations. The Ce 3d XPS lineshape showed an increase in Ce 3+ /Ce 4+ ratio with Ni coverage, providing the number of electrons donated to the ceria per Ni atom. The charge transferred per Ni is initially large but strongly decreases with increasing cluster size for both experiments and DFT, and shows large differences between clusters at steps versus terraces. This charge is localized on the interfacial Ni and Ce atoms in their atomic layers closest to the interface. This knowledge is crucial to understanding the nature of the active sites on the surface of Ni-CeO 2 catalysts for which metal-oxide interactions play a very important role in the activation of O-H and C-H bonds. In conclusion, the changes in these interactions with Ni particle size (metal loading) and the extent of reduction of the ceria help to explain how previously reported catalytic activity and selectivity change with these same structural details.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Practical Considerations for Testing Polymer Electrolytes for High-Energy Solid-State Batteries

Polymer electrolytes are an important class of materials in enabling solid-state batteries, which have the potential to exceed 400 Wh/kg energy density. Despite significant advancements in their lithium-ion transport and mechanical properties over the last two decades, the integration and testing of these novel electrolyte materials into functioning cells with the electrode loadings and dimensions required to meet the cell-level energy density goals have been limited. Here, through multiple representative examples, we demonstrate the need of testing in close to practical cell conditions for a faster and more reliable evaluation of polymeric electrolytes. In particular, the need for testing with thin lithium anodes and practical cycling capacities is demonstrated for evaluation of their lithium-metal interfacial stability and dendritic resistance, respectively, and a testing protocol is suggested. The guidelines presented here will also apply to testing of other solid electrolytes for solid-state batteries.

25 ENERGY STORAGE↗