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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Sintered plaque characteristics

The structural transformations occurring during sintering, the fabrication of a slurry produced sintered plaque, are detailed. Degradation of the positive electrode in performance in cycling in a nickel hydrogen battery were traced to the quality of the sintered plaque. Electrode degradation was found to be a limiting factor in the battery cycle life. Details of microstructural characterization and distribution of pores, examination of plastic flow during shrinkage, and observations of the rounding of nickel powder particles during the slurry process are presented.

Vaidyanathan, H.↗
NASA NTRS1988

Microstructures in rapidly solidified niobium aluminides

The microstructures of niobium aluminides produced by chill block melt spinning were compared to those of niobium aluminides produced by conventional casting. The rapidly solidified alloys were rapidly solidified by melt spinning in an argon atmosphere, and the melt-spun ribbons were examined by optical, X-ray, and TEM techniques. Microstructures were found to range from single-phase for Nb-75 at. pct Al (NbAl3) to two phase for Nb-46 at. pct Al (NbAl3 + Nb2Al). It was found that the melt spinning of Nb-aluminides produced finer grained microstructures than those produced in induction-melted ingots or in powders produced by the rotating electrode process. Ternary additions such as Cr, Ti, and Si tended to form intermetallic phases along the grain boundaries.

Hebsur, Mohan G.↗
DOE OSTI2025

Heterogeneity of the Dominant Causes of Performance Loss in End-of-Life Cathodes and Their Consequences for Direct Recycling

Recycling Li-ion batteries from electric vehicles is critical for reducing costs and supporting the development of a domestic battery supply chain. Direct recycling of cathodes, like LiNixMnyCozO2 (NMC), is attractive due to its low cost, energy use, and emissions compared to traditional recycling techniques. However, a comprehensive understanding of the active material properties at end-of-life is needed to guide direct recycling processes and the performance-dependent reuse applications. Here, NMC material from an end-of-life commercial pouch cell is characterized and bench-marked against pristine non-cycled counterparts with respect to capacity, impedance, crystallography, morphology, and microstructure to identify major degradation modes and understand variability in the end-of-life material. The spatial heterogeneity of each property throughout the cell is also quantified. While the degraded material demonstrated similar capacity as the pristine, its impedance and rate capability are severely diminished. Furthermore, samples from the periphery of the electrode layers showed more severe performance loss compared to samples extracted from central regions. The dominant culprit of performance loss is the material microstructure, where the magnitude of particle cracking showed the strongest correlation to the impedance components that are most unfavorably impacted. This work suggests severe cracks in cathode active materials are the primary challenge that direct recycling methods must overcome.

25 ENERGY STORAGE↗
DOE OSTI2025

Linking Pressure to Electrochemical Evolution in Solid-State Conversion Cathode Composites

Conversion-type cathodes, such as sulfur, FeS 2 , and FeF 3 , offer high theoretical capacities in solid-state lithium batteries but are hindered by substantial volume changes during cycling, leading to interfacial contact loss, crack formation, and microstructural degradation. Here, we investigate the relationships between electrochemical, mechanical, and structural evolution in solid-state electrode composites with these three active materials. Using real-time stack-pressure monitoring, synchrotron X-ray absorption spectroscopy, and electrokinetic modeling, we elucidate how stress evolution is linked to reversible and irreversible redox reactions. Nonlinear stack pressure evolution in cells with sulfur, FeS 2 , and FeF 3 electrode composites is found to arise from material-specific volume changes, the balance of volume change between the working and counter electrode, and the formation of distinct reaction intermediates. The three materials exhibit distinct stack pressure evolution, which is closely related to the different reaction processes in the materials, as demonstrated with X-ray absorption spectroscopy measurements. Through mesoscale modeling, we relate the experimental measurements to species evolution at the particle scale and track the dynamic coexistence of intermediate phases. Our findings highlight the importance of designing for volume changes of a given active material in solid-state battery systems.

batteries↗
DOE OSTI2025

Dusty Gas Model for Solid Oxide Fuel Cell Fuel Electrode

This model applies the Dusty Gas Model simulate multi-component species transport in SOFC (solid oxide fuel cell) anodes which considers the pressure gradient across the fuel electrode. This studyhas been verified with the analytical solution for different fuel electrode thicknesses and with literature values. The model was developed using the VoronoiFVM platform in Julia which is a built in implicit and semi implicit solver that integrates electrochemical behavior, microstructural effects, and transient analysis for accurate prediction of species transport under varying conditions.

dusty gas model (DGM)↗
NASA NTRS1992

Charge-Carrier-Scattering Spectroscopy With BEEM

Ballistic-electron-emission microscopy (BEEM) constitutes basis of new spectroscopy of scattering of electrons and holes. Pointed tip electrode scans near surface of metal about 100 angstrom thick on semiconductor. Principle similar to scanning tunneling microscope, except metal acts as third electrode. Used to investigate transport phenomena, scattering phenomena, and creation of hot charge carriers in Au/Si and Au/GaAs metal/semiconductor microstructures.

Hecht, Michael H.↗
DOE OSTI2026

Image processing workflow yielding high contrast synchrotron nanoscale computed tomography data from Ni-YSZ electrodes

The operating lifetime of Ni-YSZ fuel electrodes used in solid oxide electrolysis cells and fuel cells (SOECs and SOFCs) is limited by Ni redistribution, one of the primary degradation mechanisms that must be overcome to extend the longevity and maximize the performance of SOECs and SOFCs. To achieve this, 3D microstructural data is needed to relate both initial performance and performance loss over time to microstructural properties and their evolution throughout operation under various conditions. However, 3D microstructure data remains relatively scarce within the literature due to multiple challenges in acquiring and analyzing such data reliably. This work presents a workflow for acquiring and processing synchrotron X-ray nanoscale computed tomography (nano-CT) data from Ni-YSZ electrodes. Parameters for each step in the nano-CT workflow are described up to the final result (a 3D reconstruction), with particular emphasis on image alignment using freely available software. Following the results of a parametric sweep of the image alignment step, high contrast, low signal-to-noise 3D nano-CT data is obtained with relatively short compute times. While the exact methods best suited to samples with different microstructural qualities, or similar Ni-YSZ nano-CT data obtained from other sources may deviate from the solution found herein, this work also generalizes the decision points and evaluation of each step to provide a starting point to adapt this workflow to other datasets.

08 HYDROGEN↗
DOE OSTI2024

Shelf-life of ball-milled catalyst inks for the fabrication of fuel cell electrodes

A major factor driving fuel cell costs is the quantity of precious metal required. Therefore, it is important to understand a timeframe where inks can be reused. Here, in this work, we explore differences between a freshly prepared catalyst ink and one that has been stored for over a year – comparing ink properties, cathode catalyst layer microstructure, and their respective fuel cell performance. Ink studies revealed smaller agglomerate sizes and a decrease in shear viscosity for the aged ink. Longer storage time also results in fewer cracks and a more uniform ionomer distribution, as evidenced by microscopy characterization of rod-coated electrodes. Lastly, polarization curves show improved performance at higher current densities for the electrode prepared from the aged ink. We rationalize such effect in terms of enhanced ionomer adsorption onto the catalyst over time.

08 HYDROGEN↗
NASA NTRS1975

The effect of microstructure and strength on the fracture toughness of an 18 Ni, 300 grade maraging steel

A 300 grade maraging steel was chosen as a vehicle by which to understand the inverse relationship between strength and toughness in high strength alloys such as the 18 Ni maraging steels. The 18 Ni, 300 grade maraging material was a commercial grade consumable-electrode, vacuum arc remelted heat obtained in the form of forged and annealed plate. The matrix contained a population of second-phase impurity inclusions which was a product of the casting and hot working processes. These inclusions did not change with subsequent precipitation hardening. Changes in microstructure resulting in strength increases were brought about by variations in aging temperature and time. Maximum strength was attained in the 300 grade maraging steel by aging at 427 C (800 F) for 100 hours. Tensile, fatigue precracked Charpy impact, and plane-strain fracture toughness tests were performed at room temperature, 20 C (68 F). With increasing strength the fracture toughness decreases as smaller and smaller inclusions act as sites for void initiation.

Psioda, J. A.↗
DOE OSTI2024

Material Discovery and Design Principles of Perovskite Oxides for Reversible Solid Oxide Cells (R-SOC)

Reversible solid oxide cells (R-SOCs) are highly efficient devices for energy conversion and storage, capable of operating for both hydrogen utilization and production. In fuel cell mode, an R-SOC consumes hydrogen or natural gas to generate electricity, while in electrolysis mode, it produces hydrogen from steam. The discover of new materials with rapid oxygen surface exchange kinetics and enduring stability is crucial for the economically viable commercialization of R-SOCs. To facilitate this pursuit, we conducted extensive Density Functional Theory (DFT) calculations and developed Machine Learning (ML) models to predict critical catalytic properties essential for R-SOCs, such as oxygen surface exchange/diffusivity, and area-specific resistance (ASR). BaCoxFeyZrzO3-d(BFCZ)(x+y+z=1) emerged as a promising family of electrode materials with high activity and stability, validated through systematic experimental study. Moreover, a robust numerical multiphysics model was developed to optimize materials and microstructure parameters, providing the ability to predict the performance of functional R-SOCs.

Liu, Jian↗
DOE OSTI2025

Nucleation-promoting and growth-limiting synthesis of disordered rock-salt Li-ion cathode materials

Disordered rock-salt oxides and oxyfluorides are promising positive electrode materials for high-performance lithium-ion batteries free of nickel and cobalt. However, conventional synthesis methods rely on post-synthesis pulverization to achieve cycling-appropriate particle sizes, offering limited control over particle microstructure and crystallinity. This accelerates degradation and complicates secondary particle processing. Here we present a synthesis strategy that enhances nucleation while suppressing particle growth and agglomeration across various disordered rock-salt compositions, including lithium–manganese–titanium oxide, lithium–manganese–niobium oxide, and lithium–nickel–titanium oxide systems. Applied to Li 1.2 Mn 0.4 Ti 0.4 O 2 , this method yields highly crystalline, well-dispersed sub-200 nm particles that form homogeneous electrode films with stable cycling behavior. Tested in cells with lithium metal as the counter electrode, these electrodes deliver ~200 mAh/g with 85% capacity retention relative to the first cycle after 100 cycles (20 mA/g, 1.5–4.8 V), and an average discharge voltage loss of 4.8 mV per cycle, compared to 38.6% retention and 7.5 mV loss per cycle for electrodes derived from pulverized solid-state particles. This approach suggests a route to enhance the performance and durability of disordered rock-salt electrodes for sustainable lithium-ion batteries.

Batteries↗
DOE OSTI2026

Modeling Single-Crystal Battery Materials: From Fundamental Understanding to Performance Evaluation

The performance of rechargeable batteries is fundamentally influenced by the physicochemical properties and microstructural features of their key material components. Recent experimental advancements have highlighted the potential of single-crystal (SC) morphologies to address inherent limitations of polycrystalline (PC) electrodes and solid-state electrolytes, offering tunable charge transport kinetics and improved cell cycling performance. Here, this review examines how state-of-the-art computational modeling, from atomistic and mesoscale to continuum-level approaches, including machine learning methodologies, has been utilized to investigate the critical factors governing the electrochemical behavior of SC battery materials. We explore how predictive modeling can elucidate the processing–structure–property–performance relationships of SC cathodes, anodes, and solid-state electrolytes, with a focus on unique SC characteristics such as crystallographic anisotropy, size effects, and facet-dependent properties. Additionally, we identify limitations in commonly used modeling techniques and discuss strategies to address these challenges. By integrating high-fidelity simulations with experimental insights, this review aims to outline a clear path for the rational design and optimization of SC battery components, paving the way for accelerated advancements in energy storage technologies.

Materials science↗
NASA NTRS1993

Superconductivity devices: Commercial use of space

A YBCO thick film containing 20 percent Ag2O with a T(sub c) of 86.8 K and J(sub c) of 108 A/sq cm was obtained. The film was fabricated by a two-step firing process, i.e., firing the film at 1000 C for 10 minutes and annealing at 970 C for 30 minutes. The two-step firing process, however, was not suitable for the multiple-lead YBCO sample due to the formation of the 211 green phase at 1000 C in the multiple-lead YBCO sample. A BSCCO thick film printed on a MgO coated MSZ substrate and fired at 845 C for 2 hours exhibited a superconducting behavior at 89 K. Because of its porous microstructure, the critical current density of the BSCCO thick film was limited. This report also includes the results of the YBCO and BSCCO materials used as oxide electrodes for ferroelectric materials. The YBCO electroded PLZT showed higher remanent polarization and coercive field than the sample electroded with silver paste. A higher Curie temperature for the PLZT was obtained from the YBCO electroded sample. The BSCCO electroded sample, however, exhibited the same Curie temperature as that of a silver electroded sample. Dissipation factors of the ferroelectric samples increased when the oxide electrode was applied.

Haertling, Gene↗
NASA NTRS1996

Sol-gel Technology and Advanced Electrochemical Energy Storage Materials

Advanced materials play an important role in the development of electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. The sol-gel process is a versatile solution for use in the fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. This processing technique is particularly useful in producing porous materials with high surface area and low density, two of the most desirable characteristics for electrode materials. In addition,the porous surface of gels can be modified chemically to create tailored surface properties, and inorganic/organic micro-composites can be prepared for improved material performance device fabrication. Applications of several sol-gel derived electrode materials in different energy storage devices are illustrated in this paper. V2O5 gels are shown to be a promising cathode material for solid state lithium batteries. Carbon aerogels, amorphous RuO2 gels and sol-gel derived hafnium compounds have been studied as electrode materials for high energy density and high power density electrochemical capacitors.

Chung-tse Chu↗
NASA NTRSDate not supplied

A Multiphysics Study to Improve Specific Energy of Primary Batteries for Low Temperature Operation for Deep Space Missions

Several lander missions on the outer planets such as Europa, Enceladus, and Titan require electrical power to operate scientific and communication equipment. The traditional power generation methods, such as a photovoltaic array, are not feasible as their efficiency drops significantly at these vast distances. The novel radioisotope power systems are not practical today based on current lander designs and the effectiveness of these systems. To perform in situ science on distant planets, a high specific energy battery (>700 Wh/kg) needs to operate for about 480 hours under cold temperatures (-40C or 0C) [1]. While a primary battery such as Li-CFx can provide high specific energy at room temperature, its specific capacity decreases significantly at low temperatures. One of the causes for this drop is low ion and electrical conductivity, and slower reaction kinetics. Slower transport and facile kinetics lead to an increase in the battery’s resistance and higher voltage drops during the cell operation, thus reducing specific capacity. Both the transport and kinetics show a strong dependence on temperature. Thus, a small temperature rise can lead to an increase in the reaction rate and ion conductivity; since the temperature, cell resistance, and specific capacity are interdependent. A conventional battery model accounts for ohmic, thermodynamic, and, electrochemical, and chemical decomposition heating. The ohmic heating can be controlled by designing a resistive microstructure and varying the ratios of the active materials [2]. The kinetics can be improved by increasing the surface area, reducing the particle size, or adding a catalyst. These parameters are often optimized to achieve high specific energy at room temperatures. A similar optimization study is not available at low temperatures and for a primary (high specific energy) battery. For this presentation, we will explore the effect of geometrical, microstructural, and material properties on optimal specific capacity at low temperatures through multiphysics simulations. The ion transport resistance depends on the porosity and the tortuosity of an electrode and the separator.

M. Mehta↗
NASA NTRS1995

A new Cu-8 Cr-4 Nb alloy for high temperature applications

Various applications exist where a high conductivity alloy with good strength and creep resistance are required. NASA LeRC has developed a Cu-8 at. percent Cr-4 at. percent Nb (Cu-8 Cr-4 Nb) alloy for these applications. The alloy is designed for use up to 700 C and shows exceptional strength, low cycle fatigue (LCF) resistance, and creep resistance. Cu-8 Cr-4 Nb also has a thermal conductivity of at least 72 percent that of pure Cu. Furthermore, the microstructure and mechanical properties of the alloy are very stable. In addition to the original application in combustion chambers, Cu-8 Cr-4 Nb shows promise for welding electrodes, brazing fixtures, and other applications requiring high conductivity and strength at elevated temperatures.

Ellis, D. L.↗
NASA NTRS1978

Measurement of the time-temperature dependent dynamic mechanical properties of boron/aluminum composites

A relatively simple flexural vibration test is developed for accurate measurement of the low-strain dynamic modulus and damping capacity of B/Al composite bar specimens from -200 C to over 500 C. The specimens are prepared from 8-ply unidirectional panels containing 50 volume percent fibers composed of 203-micron commercial boron-on-tungsten fibers. The basic test technique consists of the forced flexural vibration of the composite bar specimens at their two lowest free-free symmetrical resonant modes in a high-vacuum cryostat furnace. Specimen damping is determined from oscilloscope photographs of the free decay obtained after simultaneously removing the resonant drive signal and grounding the vibration-drive electrode. The availability of time-temperature dynamic data coupled with the predictive accuracy of composite theory suggests a future potential for using such data in examining environmental effects on composite macrostructure and microstructure.

Dicarlo, J. A.↗
DOE OSTI2025

Electroslag additive manufacturing: A pathway for high throughput near net shape production

Electroslag Additive Manufacturing (ESAM), a new high-throughput additive manufacturing (AM) method that combines Electroslag Strip Cladding (ESC) and wire arc AM (WAAM) is introduced. This combination enables the high deposition rate of ESC (more than 20 kg/h with a 60 mm strip electrode) to benefit from the precise geometric control of WAAM. As a precursor to ESAM, the ESC process is investigated in an AM context independently by evaluating both direct and staggered bead-stacking strategies and analyzing the microstructural and mechanical properties of each. This is followed by an ESAM demonstration producing an annular geometry by pairing ESC with gas tungsten arc welding (GTAW), wherein GTAW is utilized to construct annular walls that are subsequently infilled via ESC. The microstructure and mechanical properties of ESC-only AM are compared with that of the ESAM method and it is shown that printed integral retaining walls do not impact the resulting mechanical properties of ESAM. Furthermore, results indicate that ESAM-produced Alloy 625 parts exhibit tensile properties on par with cast counterparts, supporting the method’s scalability to components exceeding one metric ton, and possibly making ESAM a viable future manufacturing approach for competitive production of large-scale components currently manufactured by casting and forging.

Additive manufacturing↗