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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A mechanistic damage model for solid oxide fuel cell ceramic materials - Part I: Constitutive modeling

A multiscale mechanistic damage model for solid oxide fuel cell (SOFC) ceramics that combines micromechanics of stiffness reduction due to material porosity change and microcracking with a continuum damage mechanics (CDM) description for the evolution of microcracks up to fracture is developed in this work. The model also accounts for volumetric swelling of the anode due to redox cycling. Porosity change and swelling during redox combined with normal operating thermomechanical loads could increase the stress, strain and damage distributions in SOFC stacks leading them to failure. The proposed model involves three governing parameters: (i) the porosity in terms of the pore or void volume fraction, (ii) material swelling magnitude prescribed at a given loading step, and (iii) the damage variable that describes microcracking caused by thermomechanical loads and swelling. Pores and microcracks in the ceramics are modeled as randomly distributed ellipsoidal inclusions with negligible stiffness by an Eshelby-Mori-Tanaka formulation combined with an inclusion orientation distribution method. Microcracking damage evolution is described by a CDM formulation. Volumetric swelling is treated in a similar way to thermal expansion in the constitutive relations. After validation and numerical checks, the damage model is used to analyze a simplified SOFC positive-electrode/electrolyte/negative-electrode (PEN) structure subjected a redox cycle in addition to thermomechanical loads experienced during normal operation of a SOFC stack.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2024

Deployment of Low Temperature Aluminum Dissolution (LTAD) Technology to Retrieve H-Modified (HM) Sludge in SRS Tank 15 – 25672

Tank 15 is a 4,234,000-liter (1,118,500-gallon) Type 2 high-level waste storage tank located in H Tank Farm at the Savannah River Site. It was put into service in 1960 to receive high-activity, H-Modified (HM) waste from H Canyon. Between June 1964 and November 1972, the waste tank was filled six times, and supernate was decanted five times, leaving behind the sludge solids. Tank 15 also received a mixture of high-activity and low-activity HM waste from Tank 16. Tank 15 has more recently undergone several mixing campaigns to remove much of the sludge waste; however, the effectiveness of suspending the sludge heel via mechanical mixing has significantly diminished. Low Temperature Aluminum Dissolution (LTAD) is a process developed for the dissolution of suspended aluminum solids in a large waste storage tank. Originally intended for deployment during the preparation of sludge batches in H Tank Farm for the Defense Waste Processing Facility (DWPF), the process involves maintaining the waste storage tank at a slightly elevated temperature and highly alkaline chemistry to facilitate dissolution of aluminum solids. As mechanical heel removal efforts diminished in effectiveness in Tank 15, LTAD was selected to both reduce the volume of sludge solids remaining in the heel and to modify the sludge rheology to facilitate the suspension of additional solids using the installed mixing devices.

Campbell, Seth G.↗
DOE OSTI2020

Hydrogen Enrichment for Solid Oxide Fuel Cell Gas Turbine (SOFC/GT) Hybrid Power Generation Systems Using Mechanical Gas Separation

This presentation, given at the 37 th annual Pittsburgh Coal Conference on September 8-11, 2020, includes information on the process, previous work, normal and oblique shocks model, diffuser design model, and calculation results (expansion, recompression with no losses, and recompression with mass depletion). Summary includes the concept of aerodynamic separation of water and carbon dioxide from a SYNGAS stream and that deposition was modeled by mass depletion from a compressible flow.

VanOsdol, John↗
DOE OSTI2025

Deciphering volume changes in Li-S solid-state battery components during cycling: Implication for advanced battery design

Here, in this work, we developed custom fixtures to investigate the mechanical and electrochemical behavior of all-solid-state lithium batteries during cycling under constant pressure and constant volume conditions. We successfully monitored vertical displacements during constant pressure cycling and pressure variations during constant volume cycling, allowing us decouple volume changes in the sulfur, Li 2 S cathodes, LixIn anode, and solid-state electrolyte. Scanning electron microscopy and electrochemical impedance spectroscopy confirmed that two structural changes occur during ASSLB cycling: (1) irreversible fractures in the active material particles, and (2) void formation within the electrode matrix. While the fractures in primary particles are permanent, void formation can be mitigated through stack pressure, which promotes particle rearrangement in the electrode matrix. Our findings emphasize the importance of stack pressure in maintaining the microscale integrity of all-solid-state lithium batteries, preventing void formation and enhance battery performance and durability.

Cell Design↗
DOE OSTI2024

Lithium Dendrite-Free Li 7 N 2 I-LiOH Solid Electrolytes for High Energy Lithium Batteries

All-solid-state lithium batteries (ASSLBs) hold great potential to improve the safety and energy density of today’s lithium-ion batteries by using non-flammable inorganic solid electrolytes. Solid electrolytes (SEs) are believed to prevent Li dendrite growth because of high mechanical strength and high Li+ transference numbers. Significant advances in SE have been achieved, among which, Li7La3Zr2O12 (LLZO) and Li2S–P2S5 (LPS) are the most promising SEs for bulk-type solid-state lithium batteries because of high ionic conductivities (>10-4 S/cm2). However, in contrast to our expectations, the growth of lithium dendrites is not suppressed but is facilitated in LLZOs and LPSs regardless of dopants, porosity, and crystallinity of the electrolytes. Despite the unity Li transference number and over two-times of shear modulus than that of Li metal, the critical current densities for Li plating and stripping in these SEs are less than 1.0 mA cm-2, which is one-fourth to one-tenth of that in liquid electrolytes at room temperature. The incompatibility between LLZO and LPS with Li metal seriously limits the energy density of all-solid-state batteries. The mechanism for lithium dendrite formation and growth in SEs are still disputable. Lack of understanding of the Li dendrite formation mechanism seriously impeded the development of solid-state lithium batteries. The development of the criterion for Li dendrite suppression is essential for the success of solid electrolyte lithium batteries. In this project, a criterion for Li dendrite suppression will be developed through thermodynamics and kinetics analysis of lithium dendrite nucleation/growth, which will guide the solid-state electrolyte design. Li7N2I-LiOH, Li5NI2-LiOH and Li3YCl6 solid electrolyte with high ionic conductivity and low electronic conductivity were used to validate the criterion for lithium dendrite suppression. Different surface modifications were also explored to enhance the dendrite suppression capability of SSEs.

25 ENERGY STORAGE↗
DOE OSTI2020

A self-healing liquid metal anode with PEO-Based polymer electrolytes for rechargeable lithium batteries

In this study, a Ga-Sn liquid metal alloy material is demonstrated as a self-healing anode system due to its fluidity via operando synchrotron-based transmission X-ray microscopy and X-ray diffraction experiments. Cracks formed due to volume expansions can be recovered by the fluidity of the liquid metals. By incorporating with a poly(ethylene oxide) (PEO)-based electrolyte at 60°C, the Ga-Sn anode shows a reversible lithium insertion and extraction process with a high initial discharge specific capacity of 682 mAh g -1 , followed by delivering a capacity of 462 mAh g -1 in the second cycle at C/20 rate. Furthermore, compared with its solid counterparts, the Ga-Sn liquid metal anode demonstrates a better capability to maintain its mechanical integrity and better contact with PEO solid electrolytes due to its advantageous features of the liquid. This study suggests a potential strategy to use liquid metal alloys with polymer solid electrolyte to solve the anode challenges in rechargeable lithium batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Phase Field Modeling of Pressure Induced Densification in Solid Electrolytes

Adoption of dense and homogeneous solid electrolytes can possibly mitigate the propagation of lithium dendrites and enable lithium metal anodes. Application of external pressure helps to minimize the sintering temperature in oxide ceramics and can potentially densify softer sulfide electrolytes even under room temperature conditions. Here, a previously developed phase field-based computational scheme for predicting the high-temperature sintering-induced densification of oxide ceramic solid electrolytes is extended in the present context to capture the influence of external pressure for densifying solid electrolytes. Two different bulk deformation mechanisms, namely, "reorganization" and "creep deformation," are dominant under external pressure, which is different from the surface and grain-boundary diffusion-induced densification of solid electrolytes that occurs during high temperature sintering. External pressure also increases the points of contact between the particles, which further enhances the propensity of diffusion-induced sintering process. Results obtained from simulations indicate that densification under external pressure is independent of the solid electrolyte particle morphology. Finally, a phase map is generated between applied pressure and temperature for achieving complete densification of oxide ceramics, which can possibly guide the synthesis of thin and dense solid electrolyte separators.

25 ENERGY STORAGE↗
DOE OSTI2023

Nonlinear multi-magnon scattering in artificial spin ice

Abstract Magnons, the quantum-mechanical fundamental excitations of magnetic solids, are bosons whose number does not need to be conserved in scattering processes. Microwave-induced parametric magnon processes, often called Suhl instabilities, have been believed to occur in magnetic thin films only, where quasi-continuous magnon bands exist. Here, we reveal the existence of such nonlinear magnon-magnon scattering processes and their coherence in ensembles of magnetic nanostructures known as artificial spin ice. We find that these systems exhibit effective scattering processes akin to those observed in continuous magnetic thin films. We utilize a combined microwave and microfocused Brillouin light scattering measurement approach to investigate the evolution of their modes. Scattering events occur between resonance frequencies that are determined by each nanomagnet’s mode volume and profile. Comparison with numerical simulations reveals that frequency doubling is enabled by exciting a subset of nanomagnets that, in turn, act as nanosized antennas, an effect that is akin to scattering in continuous films. Moreover, our results suggest that tunable directional scattering is possible in these structures.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

A Unique Case of the “Goldilocks Rule” in Solid-State Electrolytes: Two Are Good, Four Are Too Many

We report the syntheses of two new series of methacrylate monomers with different backbones: ureidopyrimidinone (PU) and boron-substituted urea pyrimidine (U), which enhance both the mechanical and electrochemical properties of the solid-state electrolyte (SSE) while improving the cycle life of lithium iron phosphate (LiFePO 4 , LFP) cathodes. The PU backbone is characterized by four hydrogen bonds (H-bonds), while the U backbone bears only two. Importantly, our research reveals that two H-bonds in these monomers are optimal; in contrast, four are excessive. The exceptional mechanical properties and processability of the SSE with the U series additives, resulting from the optimal H-bonds, were unexpectedly achieved. This leads to the establishment of a “Goldilocks rule” for additive design. The key strategies include: 1) reducing hydrogen-bonding (H-bonding) sites by changing pyrimidinone to pyrimidine and 2) shifting from intermolecular to intramolecular H-bonding and π−π bonding. Furthermore, this reduction in H-bonding also offers significant advantages in processability. The advancement can be extended to electrode fabrication, making the manufacturing of all-solid-state batteries more practical and efficient.

hydrogen bonding↗
DOE OSTI2025

Facet-dependent growth and dissolution of hematite resulting from autocatalytic interactions with Fe(II) and oxalic acid

The ability to simultaneously monitor the flux of iron atoms within the solution and solid phases can provide considerable insight into mechanisms of iron oxide mineral transformations. The autocatalytic interaction between hematite and Fe(II)-oxalate has long been of interest for its environmental and industrial relevance. In this study we take advantage of iron isotopic labelling and mass-sensitive imaging at the single particle scale to determine how changes in solution composition correlate with the morphologic evolution of faceted, micrometer-sized hematite platelets. Net dissolution is confirmed through analyses of aqueous iron chemistry, as well as by quantitative atomic force microscopy. Isotopic mapping techniques show that Fe(II) readily adsorbs to (001) and (012) surfaces in the absence of oxalate, but when oxalate is present selective dissolution of the (001) surface prevails and 57Fe deposition via recrystallization is not observed. Comparison between particle microtopographies following reaction with Fe(II), oxalate, and Fe(II)-oxalate show substantially different behavior, consistent with distinct mechanisms of interaction with hematite surfaces. The extensive characterization conducted on the coupled solution/solid dynamics in this system provides new insight for distinguishing crystal growth, dissolution, and recrystallization processes.

Taylor, Sandra D. [BATTELLE (PACIFIC NW LAB)]↗
DOE OSTI2022

Self-assembling and self-healing rechargeable Li batteries Final Scientific/Technical Report

PROJECT OBJECTIVE: Investigate formation of lithium halide containing solid electrolyte interface. Characterize the structure and composition of the solid electrolyte interface surface film and morphology of the electrochemically deposited Li. Develop combinations of electrolytes (solvents + salts) and electrolyte additives that produce a highly Li-ion conducting, mechanically robust, and self-healing solid electrolyte interface to suppress Li dendrite formation and improve Coulombic efficiency.

Chiang, Yet-Ming↗
DOE OSTI2025

Correlating processing variables to material properties in recycled polypropylene: A data‐driven approach

Abstract Polypropylene (PP) is one of the most widely used plastics, yet its recycling remains limited, with less than 1% of solid waste PP being reprocessed. Mechanical recycling through extrusion is the most practical method, but inconsistent reprocessing conditions introduce variability in material properties. While temperature, screw speed, and residence time influence the thermomechanical stress applied during reprocessing, there are no standardized guidelines for optimizing these parameters. This study examines how these factors shape the properties of recycled PP, using conditions designed to mimic post‐industrial recycled (PIR) scrap. Residence time was measured using colorimetric tracking and correlated with molecular weight, viscosity, and mechanical properties over multiple extrusion cycles. Data‐driven modeling, including response surface methodology, support vector machines, and artificial neural networks, identified processing temperature as the dominant factor in material degradation, followed by residence time. Mechanical properties remained stable, while viscosity decreased predictably with increasing residence time. By linking reprocessing conditions to property evolution, this study provides a method to optimize processing parameters and reduce variability in recycled PP. These findings help manufacturers improve process control, making recycled PP more predictable for reuse in manufacturing. Highlights Study of PIR‐quality PP without additives or compatibilizers. Residence time analysis shows processing temperature drives PP property changes. Mark‐Houwink enables quick molecular weight checks for quality control. Models predict mechanical and rheological shifts in reprocessing. Optimized processing parameters minimize property degradation in recycling.

Estela‐García, John E. [Polymer Engineering Center↗
DOE OSTI2023

Structure and properties of bottlebrush polyelectrolyte complexes

Abstract Structural variation of polyelectrolytes has been shown to play an important role in altering polyelectrolyte complex (PEC) properties in recent years. However, molecular‐level details such as polyelectrolyte architecture remain underdeveloped. Here, we use a combination of ring‐opening metathesis polymerization (ROMP), atom‐transfer radical polymerization (ATRP), and postpolymerization reactions to create densely branched bottlebrushes of poly(dimethylamino ethyl methcacrylate) and poly(tert‐butyl methacrylate) with high molecular weights (MDa), which we then convert into fully charged and densely branched bottlebrushes of poly(trimethylaminoethyl methacrylate) (PTMAEMA) and poly(methacrylic acid) (PAA). We investigate the structure and properties of bottlebrush polyelectrolyte complexes (BPECs) using optical microscopy, rheology, cryogenic transmission electron microscopy (Cryo‐TEM), and small‐angle X‐ray scattering (SAXS). Bottlebrush polyelectrolyte complexes are white solids, which exhibit gel‐like mechanical properties, which we attribute to sidechain interpenetration. Using a combination of Cryo‐TEM and SAXS, we are able to outline the structural development of BPECs, detailing how the network topology, sidechain conformation, and interdigitation spacing changes as a function of salt. Our results provide a foundation for further exploration of branched architectures within polyelectrolyte complexation.

Polymer Science↗
DOE OSTI2026

The effect of varying powder feedstock chemistry and printing atmosphere on the microstructure of additively manufactured nickel-based ODS alloys: Role on stabilization of cellular structures vs. oxide dispersion formation

Nickel-based alloys have a wide variety of structural applications due to their high corrosion resistance and mechanical strength which depend on solid solution strengthening, or the formation of oxides and/or intermetallic precipitation for their properties. In this study, the microstructure of six Ni–Cr–Y–Ti–Al powder batches designed for the production of oxide dispersion strengthened nickel were compared. These batches varied in chemistry and atomization technique used which included Gas Atomization Reactive Synthesis (GARS). The batches of powder were then consolidated via Additive Manufacturing (AM) Powder Bed Fusion using Laser Beam (PBF-LB) and characterized via transmission electron microscopy to elucidate the influence of powder feedstock (i.e. synthesis methodology and chemistry) on the PBF-LB microstructure. The study investigates (i) how the amount of yttrium and titanium additions in the powder feedstock and the addition of oxygen during the processing (through GARS) affect the microstructure of the powder itself and the AM printed microstructure, and (ii) how the control of oxygen addition in the printing atmosphere during the PBF-LB printing process itself is another important parameter for achieving the formation of the wanted oxide dispersion versus the stabilization of the cellular structure (often observed in AM processed alloys). Microstructural characterization of both powder particles and additively manufactured nickel alloys in this study provide important insights into the movement of yttrium within the material upon solidification, particularly along cell boundaries, and how yttrium behaves depending on alloy chemistry. When a threshold of yttrium content is reached within the system, yttrium consistently reacts to form an intermetallic along cell boundaries instead of forming oxide nanoparticles.

36 MATERIALS SCIENCE↗