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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Indirect additive manufacturing process for producing SiC—B4C—Si composites

A method for indirect additive manufacturing of an object constructed of boron carbide, silicon carbide, and free silicon, comprising: (i) producing a porous preform constructed of boron carbide and silicon carbide by an indirect ceramic additive manufacturing (ICAM) process in which particles of a powder mixture become bonded together with an organic binder, wherein the powder mixture comprises: a) boron carbide particles, and b) silicon carbide particles, wherein at least 80 vol % of the silicon carbide particles are larger than the boron carbide particles; and wherein the boron carbide and silicon carbide particles are each included in an amount of 40-60 wt. % of the powder mixture, provided that the foregoing amounts sum to at least 95 wt. %; (ii) subjecting the porous preform to a temperature of 500-900° C. to volatilize the organic binder; and (iii) infiltrating molten silicon into pores of the porous preform to produce the object.

Cramer, Corson L.↗
DOE OSTI2023

Borate salts, polymers and composites

Described herein are borate salts useful as additives, binders, and electrolyte salts for solid state lithium ion batteries. In particular, the borate salts of Formula (I), Formula (II) and Formula (III) as described herein: can be polymerized, or can be bound to an existing polymer, to provide polymeric binders for ceramic solid state electrolytes that are themselves capable of ion transport independent of the ceramic.

Liao, Chen↗
DOE OSTI2023

Electrodes with silicon oxide active materials for lithium ion cells achieving high capacity, high energy density and long cycle life performance

Improved negative electrodes can comprise a silicon based active material blended with graphite to provide more stable cycling at high energy densities. In some embodiments, the negative electrodes comprise a blend of polyimide binder mixed with a more elastic polymer binder with a nanoscale carbon conductive additive. The silicon-based blended graphite negative electrodes can be matched with positive electrodes comprising nickel rich lithium nickel manganese cobalt oxides to form high energy density cells with good cycling properties.

Venkatachalam, Subramanian↗
DOE OSTI2024

Efficient recovery processes for the black mass from spent lithium-ion batteries

A method of recycling lithium-ion batteries is disclosed. The method includes isolating a composite electrode that comprises an electrode material adhered to a current collector with a polyvinylidene difluoride (PVDF) binder from a spent lithium-ion battery. The method also includes contacting the composite electrode in a polyol fluid capable of releasing the PVDF binder from the current collector without substantially altering either component. The composite electrode may be a cathode or an anode. The method also includes rapidly delaminating the electrode material from the current collector to give a free electrode material and a free current collector, and recovering each of the free electrode material and the free current collector from the mixture. The free electrode material may be reused to prepare another composite electrode, as well as a lithium-ion battery comprising the same, which are also disclosed.

Belharouak, Ilias↗
DOE OSTI2024

Additive manufacturing of complex objects using refractory matrix materials

A method for the manufacture of a three-dimensional object using a refractory matrix material is provided. The method includes the additive manufacture of a green body from a powder-based refractory matrix material followed by densification via chemical vapor infiltration (CVI). The refractory matrix material can be a refractory ceramic (e.g., silicon carbide, zirconium carbide, or graphite) or a refractory metal (e.g., molybdenum or tungsten). In one embodiment, the matrix material is deposited according to a binder-jet printing process to produce a green body having a complex geometry. The CVI process increases its density, provides a hermetic seal, and yields an object with mechanical integrity. The residual binder content dissociates and is removed from the green body prior to the start of the CVI process as temperatures increase in the CVI reactor. The CVI process selective deposits a fully dense coating on all internal and external surfaces of the finished object.

Terrani, Kurt A.↗
DOE OSTI2024

Ordered porous solid electrolyte structures, electrochemical devices with same, methods of making same

Provided are solid-state electrolyte structures. The solid-state electrolyte structures are ion-conducting materials. The solid-state electrolyte structures may be formed by 3-D printing using 3-D printable compositions. 3-D printable compositions may include ion-conducting materials and at least one dispersant, a binder, a plasticizer, or a solvent or any combination of one or more dispersant, binder, plasticizer, or solvent. The solid-state electrolyte structures can be used in electrochemical devices.

Wachsman, Eric D.↗
DOE OSTI2024

Lithium ion cells with high performance electrolyte and silicon oxide active materials achieving very long cycle life performance

Improved negative electrodes can comprise a silicon based active material blended with graphite to provide more stable cycling at high energy densities. In some embodiments, the negative electrodes comprise a blend of polyimide binder mixed with a more elastic polymer binder with a nanoscale carbon conductive additive. Electrolytes have been formulated that provide for extended cycling of cells incorporating a mixture of a silicon-oxide based active material with graphite active material in negative electrodes that can be matched with positive electrodes comprising nickel rich lithium nickel manganese cobalt oxides to cells with unprecedented cycling properties for large capacity cell based on a silicon negative electrode active material.

Dong, Yingnan↗
DOE OSTI2025

Influence of Water, Vacuum, and Temperature on Surface Conditions of a Zeolite‐based Molecular Sieve

Molecular sieves such as zeolite-based materials are ubiquitous in industrial separation processes. However, there is a significant gap in understanding the surface properties and adsorption mechanisms for commercial zeolites, as most research focuses on pure zeolite powders rather than industrially relevant forms. Here, this work addresses this gap in understanding by employing advanced characterization techniques, including positron annihilation spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, liquid nitrogen sorption, and Fourier-transform infrared spectroscopy, to investigate the adsorption and desorption behavior of water in commercial zeolite 13X. Our research reveals insights into the pore-filling mechanisms, the impact of material binders on adsorption properties, and the dynamics of hydration and drying processes for zeolites. Monitoring changes on a minute scale allowed the distinction between fast and slow processes leading to sample drying. The identification of positronium bound to Na + ions indicated that water molecules remain in the vicinity of Na + ions after air-drying zeolite 13X. These findings highlight the importance of various environmental conditions in restoring zeolite properties to baseline after hydration, with significant implications for optimizing industrial processes. This work sets the direction for further research aimed at developing more efficient and robust separation techniques.

Beads Binder↗
DOE OSTI2021

Rheological and pumping behaviour of 3D printable cementitious materials with varying aggregate content

3D printing with cementitious materials is an emerging technology and provides an active area of research. Despite this, there are only limited studies that examine the pumping behaviour of high yield stress fluids such as printable concrete. We present a study on the rheological behaviour of 3D printable cementitious materials with different aggregate-to-binder ratios (a/b) and analyse the pumping and printing characteristics with the measured rheological parameters. We observed that an increase in a/b resulted in a significant increase of plastic viscosity, and a nominal increase in yield stress and storage modulus. The variation in plastic viscosity and yield stress with increasing aggregate content was analysed with the Krieger-Dougherty and Chateau-Ovarlez-Trung model, respectively. Also, the rheological properties of the paste rich lubrication layer during pumping were determined with the help of a tribometer. The yield stress and viscous constant of the lubrication layer increase with the increase in a/b. The pumping pressure predictions were carried out by a suitable theoretical model by considering appropriate flow conditions for different mixtures. The variation in critical height of printed elements with an increase in a/b was correlated with the observed rheological parameters.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Autogenous formation and smart behaviors of nitrite- and nitrate-intercalated layered double hydroxides (LDHs) in Portland cement-metakaolin-dolomite blends

In this work, the influence of sodium nitrite (NaNO{sub 2}) and sodium nitrate (NaNO{sub 3}) corrosion inhibitors on the composition, structure, and chloride binding behaviors of layered double hydroxides (LDHs) formed in ternary ordinary Portland cement-metakaolin-dolomite (OPC-MK-DM) systems is studied. The results show that the nitrite and nitrate anions are preferably intercalated in the CaAl LDHs (AFm phases), but not in the MgAl LDHs (hydrotalcite-type phases) due to its limited formation in these ternary cementitious systems cured at ambient temperature. The autogenously formed nitrate- and nitrite-AFm phases are decomposed upon chloride exposure accompanied by Friedel's salts formation, potentially releasing corrosion inhibitive ions to the pore solution in a progressive manner. The NaNO{sub 2} and NaNO{sub 3} incorporation in ternary OPC-MK-DM binders marginally lowers chloride binding capacity but reduces its penetration resistance mainly due to pore coarsening. Nevertheless, a strong linear correlation can be established between the water-soluble and total chloride contents in ternary OPC-MK-DM systems, regardless of OPC replacement level and corrosion inhibitor incorporation.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Inhibition mechanisms of steel slag on the early-age hydration of cement

Steel slag inhibits the early-age hydration of cement. However, its mechanism is still unclear. In this paper, the early-age hydration kinetics and the evolution of the solid phases, aqueous species and microstructures in a cement-steel slag composite binder are investigated to explore how steel slag inhibits the early-age hydration of cement. Two novel phenomena are found: (1) steel slag slows the depletion of gypsum and reduces the formation of ettringite, and (2) steel slag significantly inhibits the precipitation of CH and CSH. The results show that the addition of steel slag increases the Ca concentration in the pore solution, reduces the supersaturation of the pore solution with respect to CH and inhibits the nucleation and growth of CSH. Based on the above results, the retardation mechanisms of steel slag on the initial setting of cement paste are explained.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Hydration of potassium citrate-activated BOF slag

Basic Oxygen Furnace (BOF) slag is currently utilized with low-grade applications or landfilled. Here, we investigate a novel route to upgrade BOF slag to a high-performance binder by chemical activation with tri-potassium citrate. The impact of tri-potassium citrate on hydration and phase assemblage of BOF slag is analyzed with a multi-technique approach. Results reveal that the addition of tri-potassium citrate considerably enhances the reactivity of brownmillerite and accelerates the hydration of belite at early ages. The majority of brownmillerite hydrates within 24 h, and the reaction kinetics is controlled by the activator dosage. The main products of BOF slag hydration are siliceous hydrogarnet and C-S-H gel. Acting as a strong water reducer, tri-potassium citrate enables the manufacture of slag pastes with high compressive strength (up to 75 MPa at 28 days) and low porosity. Leaching of heavy metals from the slag pastes fulfills the Dutch Soil Quality Decree limits.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Influence of CaO/FeO ratio on the formation mechanism and properties of alkali-activated Fe-rich slags

Highlights: • Effect of the CaO/FeO molar ratio in alkali-activated Fe-rich slags is unraveled. • Low CaO/FeO molar ratios enhance the early kinetics and compressive strength. • Reaction extent and strength further increase with higher CaO/FeO ratio after 7 days. • Fe{sup 2+}-trioctahedral layers of the binder are hydroxylated and in a silicate phase. • The final strength is determined by the influence of Ca on the reaction products. In the search for CO{sub 2} mitigating cement technologies, alkali-activated Fe-rich slags present a possible alternative. The influence of the chemical composition of the synthetic Fe-silicate slag on the reaction mechanisms is assessed by varying the CaO/FeO molar ratio. The alkali-activated Fe-rich slags consist of trioctahedral layers that are shown to be hydroxylated and in contact with silicates, in a similar way to phyllosilicate minerals. The formation of this phyllosilicate-like structure is hindered during the first days for samples with high CaO/FeO ratios, because of the partial incorporation of Ca in the trioctahedral layers. At later ages, the samples with higher CaO/FeO ratios gain in reaction extent, to exceed the reaction extent of low CaO/FeO ratios at 28 days and beyond. The increase in compressive strength is even more pronounced than the effect on the reaction extent, which underlines the importance of Ca on the inherent strength of the binding phases.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Concurrent reaction-bonded joining and densification of additively manufactured silicon carbide by liquid silicon infiltration

Here, in this study, additive-manufactured silicon carbide preforms were joined and densified by reaction bonding via liquid silicon infiltration. The silicon carbide preforms were first printed by binder jetting additive manufacturing. To demonstrate concurrent joining and densification, two preforms with carbon or parchment papers at the interface were concurrently joined and infiltrated by liquid silicon. Results showed a robust interface with thicknesses ranging from 150 to 500 µm, depending on the paper type and the number of paper layers. High-energy synchrotron X-ray revealed that β-phase silicon carbide was formed inside the interface. Finally, two additively manufactured samples with complicated channel geometry were successfully joined. Energy dispersive spectroscopy of the interface of the channeled samples showed a consistent and robust joining. This concurrent approach of joining and densification enables efficiency improvement of fabricating silicon carbide parts with complicated geometries and widens geometry freedom for additive manufacturing of silicon carbide.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Packing fraction control during additive manufacturing of powder green bodies

The demand for high performance ceramic and metal components with complex geometry necessitates developments in powder handling and green body shaping. Here, in this study, vibrational powder deposition is adapted to three-dimensional printing with the ability to modulate packing fraction during printing. Boron carbide powder with sub-micron primary particle size is printed over a packing fraction range of 25.0 % to 46.5 % (below the poured density to above the tapped density). Solid metal powders are printed at 67.5 %, which enables novel freestanding, vertical-walled features without binder. These capabilities introduce opportunities for more complex geometries in high-performance materials, e.g. large-scale uniaxial hot-pressing of ceramic ballistic armor components with graded thickness and three-dimensional curved or stepped features (by compensating for displacement differences during compaction). This technology also enables multi-material patterning of additive manufacturing powder beds with reduced feedstock quantity requirements and wastage.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Additive manufacturing and testing of a ceramic heat exchanger for high-temperature and high-pressure applications for concentrating solar power

Heat exchangers with excellent corrosion and oxidation resistances are essential for the next-generation concentrating solar power (CSP) plants using a molten salt heat transfer fluid and a supercritical CO 2 Brayton power cycle that can operate at temperatures > 700 °C for higher efficiencies. Techniques were developed for additively manufacturing ceramic materials for applications involving high temperature, high pressure, and high corrosion resistance as needed for the CSP application. Based on a previous ceramic heat exchanger design with its cross-section geometry of the flow channels optimized for heat transfer and mechanical strength, lab-scale prototype heat exchangers, with integrated headers and incorporated flow channel dimensional compensations, were fabricated by using the binder jetting process. The printed prototype heat exchangers were successfully densified through the processes of liquid polymer infiltration and pyrolysis. In addition, thermophysical properties of the densified silicon carbide parts were measured to provide necessary design information. Experimental heat transfer testing of the lab-scale prototype heat exchanger was conducted, and the experimental data agreed reasonably well with the simulated results. Furthermore, this agreement provides validation of the simulation models for their applicability to the development of a full-scale ceramic heat exchanger.

14 SOLAR ENERGY↗
DOE OSTI2023

Cell-Format-Dependent Mechanical Damage in Silicon Anodes

Strong binders can be counterproductive for silicon anodes. Here, we show that stresses from cycling Si-based electrodes can cause permanent stretching and wrinkling of the current collector. Furthermore, this deformation damages the electrode coating and accelerates cell aging due to the inactivation of Si domains and facilitation of Li plating. Interestingly, we demonstrate that the formation of wrinkles is size-dependent, being present in pouch cells but absent from coin cells. This size-dependent performance decay indicates that, in extreme cases, testing outcomes are highly dependent on scale and that the validation of battery materials may require testing at larger cell formats.

25 ENERGY STORAGE↗
DOE OSTI2022

Thermal stability of anisotropic bonded magnets prepared by additive manufacturing

Abstract In this research, anisotropic NdFeB + SmFeN hybrid and NdFeB bonded magnets are additively printed in a polyphenylene sulfide (PPS) polymer binder. Printed NdFeB + SmFeN PPS bonded magnets displayed excellent magnetic properties ( B r [remanence] = 6.9 kG [0.69 T], H cj [coercivity] = 8.3 kOe [660 kA/m], and BH max [energy product] = 9.9 MGOe [79 kJ/m 3 ]) with superior corrosion resistance and thermal stability. The anisotropic NdFeB bonded magnet shows a high coercivity of 14.6 kOe (1162 kA/m) with a BH max of 8.7 MGOe (69 kJ/m 3 ). The coercivity and remanence temperature coefficients for NdFeB + SmFeN hybrid bonded magnets are −0.10%/K and −0.46%/K, and for NdFeB bonded magnets are −0.14%/K and −0.53%/K in the range of 300–400 K, indicating that the hybrid bonded magnets are thermally stable. The average flux aging loss for hybrid magnets was also determined to be very stable over 2000 h at 448 K (175°C) in air with 2.04% compared to that of NdFeB magnets with 3.62%.

thermal stability↗