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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Electron-Phonon Renormalization in the Proton-Conducting Electrolyte Ba Zr O 3 and Its Implications for High-Temperature Electrolysis

Electrical leakage is an inherent problem in solid-oxide fuel and electrolyzer cells, limiting their energy-conversion efficiency. High concentrations of electrons or holes can exacerbate this issue. However, it is largely unclear how the typical high operating temperatures of the systems influence their charge-carrier concentrations. In this work, we use first-principles calculations to examine how lattice vibrations impact electrical conductivity in conventional electrolytes, using Ba Zr O 3 as a representative material. Our analysis shows that phonon-induced shifts in the band gap and band edges lead to a dramatic increase in p -type carrier concentrations at temperatures above 600 K, compared to models that neglect temperature effects. Additionally, we reveal the importance of oxygen-ion motion on band-edge positions, which makes valence-band-edge shift dominate the band-gap change. Our study provides a protocol for calculating phonon-induced changes in similar oxides, paving the way for interrogating electrical leakage in electrolytes for high-temperature operation. Published by the American Physical Society 2025

25 ENERGY STORAGE↗
NASA NTRS1999

"Application of Tunable Diode Laser Spectrometry to Isotopic Studies for Exobiology"

Computer-controlled electrically-activated valves for rapid gas-handling have been incorporated into the Stable Isotope Laser Spectrometer (SILS) which now permits rapid filling and evacuating of the sample and reference gas cells, Experimental protocols have been developed to take advantage of the fast gas handling capabilities of the instrument and to achieve increased accuracy which results from reduced instrumental drift during rapid isotopic ratio measurements. Using these protocols' accuracies of 0.5 del (0.05%) have been achieved in measurements of 13C/12C in carbon dioxide. Using the small stable isotope laser spectrometer developed in a related PIDDP project of the Co-I, protocols for acquisition of rapid sequential calibration spectra were developed which resulted in 0.5 del accuracy also being achieved in this less complex instrument. An initial version of software for automatic characterization of tunable diode lasers has been developed and diodes have been characterized in order to establish their spectral output properties. A new state-of-the-art high operating temperature (200 K) mid infrared diode laser was purchased (through NASA procurement) and characterized. A thermo-electrically cooled mid infrared tunable diode laser system for use with high temperature operation lasers was developed. In addition to isotopic ratio measurements of carbon and oxygen, measurements of a third biologically important element (15N/14N in N2O gas) have been achieved to a preliminary accuracy of about 0.2%. Transfer of the basic SILS technology to the commercial sector is proceeding under an unfunded Space Act Agreement between NASA and SpiraMed, a medical diagnostic instrument company. Two patents have been issued. Foreign patents based on these two US patents have been applied for and are expected to be issued. A preliminary design was developed for a thermo-electrically cooled SILS instruments for application to planetary space flight exploration missions.

Sauke, Todd B.↗
DOE OSTI2024

Thermal Conversion of Ultrathin Nickel Hydroxide for Wide Band Gap 2D Nickel Oxides

Wide band gap (WBG) semiconductors (E g > 2.0 eV) are integral to the advancement of next-generation electronics, optoelectronics, and power industries owing to their capability for high-temperature operation, high breakdown voltage, and efficient light emission. Enhanced power efficiency and functional performance can be attained through miniaturization, specifically via the integration of device fabrication into a two-dimensional (2D) structure enabled by WBG 2D semiconductors. However, as an essential subgroup of WBG semiconductors, 2D transition metal oxides (TMOs) remain largely underexplored in terms of physical properties and applications in 2D optoelectronic devices, primarily due to the scarcity of sufficiently large 2D crystals. Thus, our goal is to develop synthesis pathways for 2D TMOs possessing large crystal domains (e.g., >10 μm), expanding the 2D TMO family and providing insights for future engineering of 2D TMOs. Here, we demonstrate the synthesis of WBG 2D nickel oxide (NiO) (E g > 2.7 eV) thermally converted from 2D nickel hydroxide (Ni(OH) 2 ) with a lateral domain size larger than 10 μm. Moreover, the conversion process is investigated using various microscopic techniques, such as atomic force microscopy, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, providing significant insights into morphology and structural variations under different oxidative conditions. The electronic structure of the converted Ni x O y is further investigated using multiple soft X-ray spectroscopies, such as X-ray absorption and emission spectroscopies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1986

Laser-powered MHD generators for space application

Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

Jalufka, N. W.↗
DOE OSTI2022

Development of Temperature Compensation Tools for SPNDs Operating in High Temperature Environments

Two rhodium-based self-powered neutron detectors (Rh-SPNDs) were irradiated at the Massachusetts Institute of Technology Reactor as a follow-on experiment to the heated irradiation previously conducted at the Neutron Radiography facility at Idaho National Laboratory. The experiment was conducted over the temperature ranges of 600-850°C to further examine the effects of temperature on the Rh-SPNDs. Four tests of varying temperature and power were performed. The tests identified two types of temperature effects consistent with historical evaluations. One effect is a prompt proportionality to temperature at steady-state reactor power due to the decrease in Rh-SPND insulation resistance. The other effect is a delayed effect generated from displacement currents generated by changing the space charge within the insulator as a function of temperature. The result of this experiment demonstrates a characterizable responses to temperature that is feasible for developing a temperature compensation tool for SPND operating in high temperatures. The characteristics identified in this experiment will be integrated within the delayed-response compensation techniques for FY23 evaluation.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Demonstration of Temperature Compensation Techniques for SPNDs Operating in High Temperatures

This report presents the testing results of rhodium-based self-powered neutron detectors (Rh-SPND) irradiated in a furnace dry tube from ambient temperature to 850°C at the Ohio State University Research Reactor. The purpose of the experiment is to demonstrate the technique and application of a temperature compensation technique for the Rh-SPND. This is performed by characterizing the temperature effects observed in past experiments—a displacement current and a stabilized dark current—of the Rh-SPND as a function of temperature under the models of shifting space charges as a product of photoconductivity properties. Low-power irradiation at the OSURR was performed with stabilized temperatures of ambient, 550, 575, 600, 625, 650, 675, and 700°C were first performed to obtain the curve fit parameters that describes the temperature effects. The results provided further insight for the behavior of the SPND at high temperatures in accordance with available insulation conductivity models. Transition points from photoconductivity to ionic conductivity were identified in the range of 550–600°C. Additionally, transition points ionic to electric conductivity were observed in the range of 675–700°C, however, the data was not able to fully capture the transition and did not have enough resolution to provide predictive compensation based only on temperature readings.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1991

Silicon carbide, an emerging high temperature semiconductor

In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

Matus, Lawrence G.↗
NASA NTRS2002

Packaging Technology for SiC High Temperature Circuits Operable up to 500 Degrees Centigrade

New high temperature low power 8-pin packages have been fabricated using commercial fabrication service. These packages are made of aluminum nitride and 96 percent alumina with Au metallization. The new design of these packages provides the chips inside with EM shielding. Wirebond geometry control has been achieved for precise mechanical tests. Au wirebond samples with 45 degree heel-angle have been tested using wireloop test module. The geometry control improves the consistency of measurement of the wireloop breaking point.Also reported on is a parametric study of the thermomechanical reliability of a Au thick-film based SiC die-attach assembly using nonlinear finite element analysis (FEA) was conducted to optimize the die-attach thermo-mechanical performance for operation at temperatures from room temperature to 500 degrees Centigrade. This parametric study centered on material selection, structure design and process control.

Chen, Lian-Yu↗
NASA NTRS1973

High intensity copper atom beam - Preliminary results

The development of a nozzle which gas-dynamically accelerates neutral copper atoms at controlled energy levels and flux rates suitable for the investigation of inelastic copper atom collision processes is reported. Preliminary test data demonstrate that vapor-deposited rhenium nozzles do not degrade in the presence of copper vapor at high temperatures. Operation with high purity helium gas at nozzle stagnation temperatures in the range 2650-2700 K and total stagnation pressures from 1/4 to 2 atm with continuous copper atom flux rates of approximately 10 to the 18th power per second has been maintained, for a total time of 8-1/2 h to date.

Kelly, A. J.↗
DOE OSTI2023

Power Electronics Materials and Bonded Interfaces - Reliability and Lifetime

High temperature operation of wide bandgap devices continue to be a challenge for the power electronics packages. Thermal performance and reliability are important factors that determine the viability of a bonded interface for operation at high temperatures. In this presentation, we present the technical approach and key results from the research on sintered silver, transient liquid phase alloy, and polymeric materials. A lifetime prediction model that incorporates the thermomechanical behavior of sintered silver at 200C was developed. The copper-aluminum transient alloy completed 350 thermal cycles from -40C to 200C and little increase in the defect level was observed. In addition to material research, we initiated a time-series analysis on the scanning acoustic microscope images of eutectic solder to explore statistical forecasting methods and machine learning techniques. Initial results that report the accuracy of a few different statistical models are presented.

ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2025

Voltage cycling as a dynamic operation mode for high temperature electrolysis solid oxide cells

Solid Oxide Electrolysis Cells (SOECs) have emerged as a promising technology for the efficient production of H2 via high-temperature electrolysis. However, power input from dynamic energy sources remains a significant challenge for their long-term stability. It is important to analyze the tolerance of cells under dynamic operation conditions. This study focuses on evaluating the impact of voltage cycling on the performance and durability of electrode-supported SOECs. We explore the operational limits and degradation mechanisms of SOECs subjected to various voltage conditions and find that the cells have high tolerance for dynamic voltage. Voltage cycling between 1.3 V and 1.5 V for 9000 cycles does not damage the cell. Conversely, cycling to higher voltages (≥1.7 V) results in accelerated degradation. Advanced characterization is used to screen for various degradation modes post operation. Within the oxygen electrode, XRD and STEM EDS find compositional and phase evolution in all voltage cycled samples including increased decomposition of the air electrode resulting in cation migration. Microstructural analysis of the fuel electrode from nano-CT data shows minimal change throughout the sample set and no evidence of Ni migration, indicating the fuel electrode is stable and not impacted by cycling to higher voltages within the timeframe studied.

Zhu, Zhikuan↗
NASA NTRS1978

Solar thermal collectors using planar reflector

Specular reflectors have been used successfully with flat-plate collectors to achieve exceptionally high operating temperatures and high delivered energy per unit collector area. Optimal orientation of collectors and reflectors can result in even higher performance with an improved relationship between energy demand and supply. This paper reports on a study providing first order optimization of collector-reflector arrays in which single- and multiple-faceted reflectors in fixed or singly adjustable configurations provide delivered energy maxima in either summer or winter.

Espy, P. N.↗
NASA NTRS2004

An Overview of Magnetic Bearing Technology for Gas Turbine Engines

The idea of the magnetic bearing and its use in exotic applications has been conceptualized for many years, over a century, in fact. Patented, passive systems using permanent magnets date back over 150 years. More recently, scientists of the 1930s began investigating active systems using electromagnets for high-speed ultracentrifuges. However, passive magnetic bearings are physically unstable and active systems only provide proper stiffness and damping through sophisticated controllers and algorithms. This is precisely why, until the last decade, magnetic bearings did not become a practical alternative to rolling element bearings. Today, magnetic bearing technology has become viable because of advances in micro-processing controllers that allow for confident and robust active control. Further advances in the following areas: rotor and stator materials and designs which maximize flux, minimize energy losses, and minimize stress limitations; wire materials and coatings for high temperature operation; high-speed micro processing for advanced controller designs and extremely robust capabilities; back-up bearing technology for providing a viable touchdown surface; and precision sensor technology; have put magnetic bearings on the forefront of advanced, lubrication free support systems. This paper will discuss a specific joint program for the advancement of gas turbine engines and how it implies the vitality of magnetic bearings, a brief comparison between magnetic bearings and other bearing technologies in both their advantages and limitations, and an examination of foreseeable solutions to historically perceived limitations to magnetic bearing.

Clark, Daniel J.↗
NASA NTRS2019

Design of Materials for IR Detectors Using High Z Elements for High Energy Radiation Environment

There is a strong need for rad hard and high operating temperature IR detectors for space environment. Heavy metal Selenides (high Z and large density) have been investigated for more than half century for high operating temperature mid wave infrared (MWIR) applications. Most of the efforts have been devoted to make detector arrays on high-resistivity Si substrates for operating wavelengths in the 1.5 to 5.0 m region using physical vapor transport grown poly crystalline materials. For most of the biological spectral and imaging applications, short wave infrared (SWIR) detectors have shown better performance. Recent growth materials have shown variation in morphology with slight change in growth conditions and hence variation in performance parameters such as bandgap, mobility and resistivity from sample to sample. We have performed growth and optical characterization of binary materials CdSe-PbSe to determine the suitability for IR detector. We have determined bandgap using several theoretical models for different morphologies observed during growth on silicon wafers.

Saraf, Sonali↗
NASA NTRS2020

Radiometric Performance Characterization of the CubeSat Infrared Atmospheric Sounder (CIRAS) High Operating Temperature-Barrier Infrared Detectors (HOT-BIRD))

The CubeSat Infrared Atmospheric Sounder (CIRAS) is a remote sensing instrument under development for thedemonstration and technology maturation of hyperspectral infrared sounding in a 6U CubeSat. The CIRASinstrument utilizes a 2D Focal Plane Array (FPA) of High Operating Temperature-Barrier Infrared Detectors(HOT-BIRD). The HOT-BIRD material provides improved uniformity, higher allowable operating temperatures,and lower 1/f noise. The performance of the HOT-BIRD FPA was tested inside a Integrated Dewarand Cryocooler Assembly (IDCA), allowing the operating temperature of the FPA to reach low temperatures.Experimentation involved using an external Blackbody Calibrator Target (BCT) to generate numerous imagesof the BCT object at varying scene temperatures. The data acquired was compared to a radiometric model tocharacterize the responsivity of the detectors. In addition, a solid angle correction was developed to improve theaccuracy of the modeling. Real and synthetic images are presented in the comparative analysis to validate theexpected responsivity of the detectors through calculation of the quantum efficency.

Rafol, Sir B.↗
NASA NTRS2014

Lightweight Radiator for in Space Nuclear Electric Propulsion

Nuclear electric propulsion (NEP) is a promising option for high‐speed in‐space travel due to the high energy density of nuclear fission power sources and efficient electric thrusters. Advanced power conversion technologies may require high operating temperatures and would benefit from lightweight radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Game‐changing propulsion systems are often enabled by novel designs using advanced materials. Pitch‐based carbon fiber materials have the potential to offer significant improvements in operating temperature, thermal conductivity, and mass. These properties combine to allow advances in operational efficiency and high temperature feasibility. An effort at the NASA Marshall Space Flight Center to show that woven high thermal conductivity carbon fiber mats can be used to replace standard metal and composite radiator fins to dissipate waste heat from NEP systems is ongoing. The goals of this effort are to demonstrate a proof of concept, to show that a significant improvement of specific power (power/mass) can be achieved, and to develop a thermal model with predictive capabilities making use of constrained input parameter space. A description of this effort is presented.

Craven, Paul↗
DOE OSTI2023

Smooth, homogeneous, high-purity Nb 3 Sn superconducting RF resonant cavity by seed-free electrochemical synthesis

Abstract Workbench-size particle accelerators, enabled by Nb 3 Sn-based superconducting radio-frequency (SRF) cavities, hold the potential of driving scientific discovery by offering a widely accessible and affordable source of high-energy electrons and x-rays. Thin-film Nb 3 Sn RF superconductors with high quality factors, high operation temperatures, and high-field potentials are critical for these devices. However, surface roughness, non-stoichiometry, and impurities in Nb 3 Sn deposited by conventional Sn-vapor diffusion prevent them from reaching their theoretical capabilities. Here we demonstrate a seed-free electrochemical synthesis that pushes the limit of chemical and physical properties in Nb 3 Sn. Utilization of electrochemical Sn pre-deposits reduces the roughness of converted Nb 3 Sn by five times compared to typical vapor-diffused Nb 3 Sn. Quantitative mappings using chemical and atomic probes confirm improved stoichiometry and minimized impurity concentrations in electrochemically synthesized Nb 3 Sn. We have successfully applied this Nb 3 Sn to the large-scale 1.3 GHz SRF cavity and demonstrated ultra-low BCS surface resistances at multiple operation temperatures, notably lower than vapor-diffused cavities. Our smooth, homogeneous, high-purity Nb 3 Sn provides the route toward high efficiency and high fields for SRF applications under helium-free cryogenic operations.

Physics↗
DOE OSTI2026

Robust dynamic operation of high temperature electrolysis solid oxide cells

Here, this study evaluates the durability of Ni/YSZ-supported SOECs under dynamic operating conditions relevant to real-world applications. Systematic tests were conducted to assess cell performance under steam cycling (3 to 75% humidified H 2 ), mode cycling between SOFC and SOEC operation, thermal cycling (150 to 750 °C at OCV, and 600 to 800 °C at 1.3V), and redox cycling (between 50% humidified H 2 and 50% humidified N 2 ). Steam cycling, mode cycling, and thermal cycling at OCV do not significantly accelerate performance degradation. Thermal cycling at 1.3V caused minimal damage within 600 to 800 °C. Full redox cycling (multi-hour oxidation holds) induced cell structural failure, while partial redox cycling (0.5 h holds) was tolerated. Extensive characterization revealed some material evolution, namely Sr and Co secondary phase formation, within the oxygen electrode due to La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ instability, especially for steam cycling and mode cycling. Minimal changes were identified within the Ni-YSZ fuel electrodes. These findings provide critical insights into SOEC reliability under dynamic conditions, supporting their application in dynamic or intermittent energy systems.

08 HYDROGEN↗