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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Observation of N-rich solid-electrolyte interphase by ToF-SIMS.

Formation of a stable solid electrolyte interphase (SEI) between lithium electrodes and electrolyte upon multiple charge/discharge cycles is crucial to a long-term lithium-ion battery performance. Addition of LiNO3 to lithium bis (fluorosulfonyl) imide/poly(ethylene oxide) (LiFSI/PEO) electrolyte leads to a durable SEI that is electrically insulating yet highly conductive to Li ions, chemically and electrochemically stable, physically uniform, and mechanically robust. ToF-SIMS was used here in combination with sputtering by a gaseous cluster ion beam (GCIB) to examine how the addition of a small proportion of LiNO3 to the LiFSI/PEO electrolyte affects the SEI composition. Negative ion ToF-SIMS spectra of the cycled samples display an intense m/z 26 peak associated with the SEI. Exact mass assignments and isotopic ratios indicate that this peak should be assigned as (CN-)-C-12, with little to no negative secondary ion signal arising from (LiF-)-Li-7. This CN- signal appears to arise from an N-rich portion of the SEI adjacent to the Li electrode that is depleted in LiF relative to the bulk electrolyte. The dearth of LiF- (and LiF+ from the positive ion spectra) is unexpected because LiF has been identified in the SEI in similar samples. Finally, GCIB sputtering indicates that the SEI adheres more strongly to the Li electrode than to the LiFSI/PEO electrolyte.

Shavandi, Seyedeh Reyhaneh↗
DOE OSTI2025

Updates to the Hanford Soil Inventory Model (SIM Version 2) for FY 2025

Update SIM to newest version (SIMv2.3). SIM is being updated to reflect the updates to the tank leak inventories performed in ECF-HANFORD-24-0061. This update is also being done to publish the site inventories in both 2001 decayed and back-decayed formats. This is particularly needed for modeling that requires inventory data from before 2001 that includes decay information for radionuclides.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Analysis on Evaluations of Monterey Bay Aquarium Research Institute’s Wave Energy Converter’s Field Data Using WEC-Sim and Gazebo: A Simulation Tool Comparison

Although many studies have validated wave energy converter (WEC) numerical models against scaled prototype experimental data, there remains a notable lack of validation using data from full-scale deployed WECs. This paper compares two numerical models of Monterey Bay Aquarium Research Institute’s Wave Energy Converter (MBARI-WEC), a two-body point absorber with an electro-hydraulic power take-off system (PTO). The models are implemented in WEC-Sim/Simscape and Gazebo Simulator. A statistical analysis of the models was performed, and field results were obtained to compare the models’ accuracy in predicting the RMS piston velocity, RMS motor speed, and mean electric power compared to field data for 56 observations across varying sea states. The Gazebo model demonstrated a closer agreement across all three parameters for a majority of the observations. When compared to the field data, the Gazebo and WEC-Sim models exhibited average mean electric power overestimations of 13% and 22%, respectively.

16 TIDAL AND WAVE POWER↗
DOE OSTI2025

Direct observation of key aluminum hydroxide prenucleation oligomers for gibbsite nucleation and crystallization in sodium aluminate solution by liquid ToF-SIMS

The mechanism of gibbsite (aluminum hydroxide) crystallization from highly alkaline solutions such as Bayer liquors remains poorly understood, where aluminum (Al) transforms from largely tetrahedrally coordinated aluminate monomers in sodium aluminate solutions into a network of octahedra in gibbsite crystals. A variety of traditional analytical approaches applied to this system do not readily reveal the presence of higher-order oligomeric intermediates. To overcome this limitation, we employed in-situ liquid Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to examine the Al species present in concentrated sodium aluminate solutions favoring crystallization of gibbsite or sodium aluminate. A complex mixture of Al oligomers was found. By comparing the change in the relative concentration of Al oligomers with +1 and -1 charge, we were able to identify three major Al oligomer candidates, iso-tetramers, iso-pentamers, and cyclic-hexamers, for the nucleation and crystallization of gibbsite. The concentrations of iso-tetramers and iso-pentamers significantly surpass those of cyclic-hexamers. Time-dependent in-situ Raman spectroscopy analysis indicated that the appearance of gibbsite coincided with the peak concentration of these oligomers. The Density-functional theory (DFT) calculation suggests that the formation of iso-oligomers is more favorable than that of cyclic-hexamers. The combined results suggest that iso-tetramers and iso-pentamers play the most substantial role in the nucleation and growth of gibbsite in the sodium aluminate solutions. Our findings also suggest that the oligomers that promote gibbsite crystallization are more stable in dilute sodium aluminate solutions, making these solutions particularly suitable for efficient gibbsite crystallization. In conclusion, our study fills a major knowledge gap in understanding Al speciation that leads to the nucleation and crystallization of gibbsite in concentrated sodium aluminate solutions.

Bayer liquor↗
DOE OSTI2025

Rapid Screening of Single-Atom Catalyst Synthesis Conditions Using ToF-SIMS and Facet-Dependent Single-Crystal Substrates

Single-atom catalysts (SACs) offer superior catalytic performance compared to traditional nanoparticle catalysts but are challenging to develop because of the need for extensive optimization and specialized characterization techniques. Here, this study presents a rapid and versatile method for detecting synthesis conditions and elucidating deposition mechanisms of SACs on various substrates. By depositing active elements (Au, Cu, Ni and Rh) on facet-specific single-crystalline substrates (CeO 2 , TiO 2 , MgO and Al 2 O 3 ) and employing time-of-flight secondary ion mass spectroscopy (ToF-SIMS), we assessed facet-dependent deposition behaviors and identified optimal conditions for solution-based SAC synthesis. On CeO 2 and TiO 2 , we confirmed facet-dependent deposition, primarily influenced by oxygen vacancy density and photocatalytic activity, respectively. MgO exhibited the formation of metal oxide/hydroxide clusters for all active elements, and the degree of clustering for Cu and Ni was correlated with the facet hydrolysis susceptibility. Notably, Au and Rh deposition on MgO was facet-independent, attributed to the formation of hydroxide species in solution. Al 2 O 3 , due to its chemical stability and lack of surface defects, did not show active element deposition. This study not only provides a time and cost-efficient method for prescreening SAC synthesis conditions, but it also provides valuable insights into the various deposition mechanisms governing SAC formation on different substrates, paving the way for the rational design of tailored SACs for various catalytic applications.

ToF-SIMS↗
DOE OSTI2024

The NanoSIMS-HR: The Next Generation of High Spatial Resolution Dynamic SIMS

The high lateral resolution and sensitivity of the NanoSIMS 50 and 50L series of dynamic SIMS instruments have enabled numerous scientific advances over the past 25 years. Here, in this study, we report on the NanoSIMS-HR, the first major upgrade to the series, and analytical tests in a suite of sample types, including an aluminum sample containing silicon crystals, microalgae, and plant roots colonized with a symbiotic fungus. Significant improvements have been made in the Cs + ion source, high voltage (HV) control, stage reproducibility, and other aspects of the instrument that affect performance. The modified design of the NanoSIMS-HR thermal-ionization Cs + source enables a 5 pA primary ion beam to be focused into a 100 nm spot, a ~2.5-fold increase compared to Cs + sources on previous instruments (~2 pA at 100 nm). The brightness of the new Cs + source enables an ultimate lateral resolution as high as 30 nm and improved detection limits for a given analysis area. Sample stage movement accuracy is higher than 500 nm, enabling many-fold higher throughput automated analyses. With the new HV control, the primary ion beam impact energy can be reduced from 16 to 2 keV, which enables higher depth resolution during depth profiling (a 2-fold improvement), albeit with a 5-fold decrease in lateral resolution. In the NanoSIMS-HR, the secondary ion column and detection system are identical to those used in the previous series, and the isotopic analysis performance is as precise as in previous NanoSIMS instruments.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

From Sim to Real: A Pipeline for Training and Deploying Traffic Smoothing Cruise Controllers

Designing and validating controllers for connected and automated vehicles to enhance traffic flow presents significant challenges, from the complexity of replicating real-world stop-and-go traffic dynamics in simulation, to the intricacies involved in transitioning from simulation to actual deployment. In this work, we present a full pipeline from data collection to controller deployment. Specifically, we collect 772 km of driving data from the I-24 in Tennessee, and use it to build a one-lane simulator, placing simulated vehicles behind real-world trajectories. Using policy-gradient methods with an asymmetric critic, we improve fuel efficiency by over 10% when simulating congested scenarios. Our comprehensive approach includes reinforcement learning for controller training, software verification, hardware validation and setup, and navigating various sim-to-real challenges. Furthermore, we analyze the controller's behavior and wave-smoothing properties, and deploy it on four Toyota Rav4’s in a real-world validation experiment on the I-24. Lastly, we release the driving dataset, the simulator and the trained controller, to enable future benchmarking and controller design.

42 ENGINEERING↗
DOE OSTI2026

Analysis of vapor diffusion Nb$^{3}$Sn coating at Fermilab: Minimizing impurities using TOF-SIMS

Nb₃Sn demonstrates steady advancements nowadays offering reduced power cost in superconducting radio-frequency cavities due to its high critical temperature, quality factor, and achieved accelerating gradient. However, theoretical estimates of its radio-frequency parameters have not been achieved due to several potentially limiting mechanisms: tin spots, patchy regions, defects, thermal impedance, and impurities. While some of these limitations have been intensively studied, impurity analysis in Nb$_3$Sn coatings have received less attention. We report an investigation of impurities in several vapor-diffused Nb₃Sn coated samples using time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and show allowable impurity levels in view of superconducting cavity performance. Challenges and lessons learned in maintaining clean Nb$_3$Sn coatings are also discussed.

Tagdulang, Nikki [Fermilab]↗
DOE OSTI2025

Chemical Analysis of Tantalum Thin Films compared to Niobium Thin Films using SIMS and XPS

Superconducting qubits are a leading platform for quantum computation. These circuits are typically made from superconducting materials like aluminum or niobium. However, the amorphous niobium oxide and aluminum oxide on the surface of these circuits introduce considerable RF loss due to the presence of two-level systems (TLS), which limits the maximum coherence times T1 to ~100 μs. Capping the niobium qubits with a tantalum layer leads to a 3- 5x improvement [Bal et al., 2024]. But even in this case, tantalum forms an amorphous surface oxide that introduces loss. In an effort to devise strategies to eliminate the presence of this oxide, we present a comprehensive study on the nature of Ta oxide using x-ray photoemission spectroscopy (XPS) and secondary ion mass spectrometry (ToF-SIMS) as a function of heat treatment. The thin films were annealed in ultra-high vacuum conditions and analyzed in situ to characterize the composition and evolution of the native tantalum oxide layer and oxide-metal interface. Our analysis reveals two critical differences between tantalum and niobium oxides: Nb2O5 completely dissolves at 400°C, while Ta2O5 persists even at 800°C. Additionally, tantalum oxide contains only a single suboxide (TaO), in contrast to niobium's two suboxides (NbO and NbO2). The suboxide of tantalum contributes minimally to the total oxide content and shows a relative increase with temperature. Understanding the oxide’s behavior will open new pathways for optimizing coherence times in tantalum qubits.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Challenges of Vapor Diffusion $Nb_3Sn$ Coating at Fermilab: Minimizing Impurities Using TOF-SIMS

Nb$_3$Sn demonstrates steady advancements nowadays offering reduced power cost in superconducting radio-frequency cavities due to its high critical temperature, quality factor, and achieved accelerating gradient. However, theoretical estimates of its radio-frequency parameters have not been achieved due to several potentially limiting mechanisms: tin spots, patchy regions, defects, thermal impedance, and impurities. While some of these limitations have been intensively studied, impurity analysis in Nb$_3$Sn coatings have received less attention. We report an investigation of impurities in several vapor-diffused Nb$_3$Snn coated samples using time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and show allowable impurity levels in view of superconducting cavity performance. Challenges and lessons learned in maintaining clean Nb$_3$Sn coatings are also discussed.

Tagdulang, N. [Fermilab]↗
DOE OSTI2026

Measurement of Inclusive Charged-Current $\barν_μ$ Scattering on C, CH, Fe, and Pb at $\langle E_{\barν}\rangle \sim$ 6 GeV with MINERvA

We report MINERvA's first measurement of inclusive charged-current $\barν_μ$ cross sections on carbon, hydrocarbon, iron, and lead, and their ratios to the cross section on hydrocarbon, as functions of the antimuon transverse momentum, $p_{\mathrm{T}}$. Using a wide-band $\barν_μ$ beam with mean energy $\sim 6~\text{GeV}$, these measurements probe all interaction modes, including the transition from resonance production to deep-inelastic scattering. The total uncertainties are typically $5-10\%$ for the absolute cross sections and $2-5\%$ for the ratios. Comparisons with multiple neutrino interaction models reveal significant discrepancies in the $p_{\mathrm{T}}$ dependence, particularly for heavier nuclei. The disagreements are most pronounced at low $p_{\mathrm{T}}$ but extend across the full $p_{\mathrm{T}}$ range, indicating missing or mis-modelled nuclear effects.

Klustová, A. [Imperial Coll., London] (ORCID:00000↗
DOE OSTI2026

Second-order wave excitation forces in WEC-Sim/MOST: Implementation, experimental validation, and code-to-code comparison

Accurate prediction of second-order hydrodynamic loads is essential for floating bodies, including floating offshore wind turbines, wave energy converters, and hybrid wind–wave platforms. These nonlinear effects, arising from both sum- and difference-frequency forcing, are critical for capturing key response characteristics but remain challenging to model efficiently. In this work, we extend the open-source Wave Energy Converter Simulator / MATLAB for Offshore Simulation Tool by implementing second-order wave excitation forces, supporting both the full Quadratic Transfer Function formulation and the Newman approximation. The full Quadratic Transfer Function method is used for all code-to-code comparisons and experimental validation, while the Newman approximation is provided as a computationally lighter alternative. To benchmark the new capability, we perform a code-to-code comparison with OpenFAST and OrcaFlex. We then validate the enhanced model using wave-tank measurements of a 1:96 scale DeepCwind semi-submersible, showing that second-order effects are required to reproduce platform motions. The implementation employs a computationally efficient pre-computation strategy for second-order wave excitation forces, reducing simulation cost while maintaining engineering accuracy. Overall, this work advances the tool as an open-source and versatile tool for modelling floating offshore renewable-energy systems requiring second-order hydrodynamic fidelity.

17 WIND ENERGY↗
DOE OSTI2025

Applying in Situ Bias During TOF-SIMS Analysis to Investigate Ion Migration in Perovskite Devices

An in situ electrical bias was placed on a perovskite device through the device thickness while under investigation with time-of-flight secondary ion mass spectrometry. The applied bias resulted in an observed reversible migration of halide and lithium ions on the timescale of minutes. The results show a framework that can be used for further study of ion migration in perovskite materials and devices.

14 SOLAR ENERGY↗