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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Enhanced plasma performance in C-2W advanced beam-driven field-reversed configuration experiments

TAE Technologies’ fifth-generation fusion device, C-2W (also called ‘Norman’), is the world’s largest compact-toroid device and has made significant progress in field-reversed configuration (FRC) plasma performance. C-2W produces record breaking, macroscopically stable, high-temperature advanced beam-driven FRC plasmas, dominated by injected fast particles and sustained in steady state, which is primarily limited by neutral-beam (NB) pulse duration. The NB power supply system has recently been upgraded to extend the pulse length from 30 ms to 40 ms, which allows for a longer plasma lifetime and thus better characterization and further enhancement of FRC performance. An active plasma control system is routinely used in C-2W to produce consistent FRC performance as well as for reliable machine operations using magnet coils, edge-biasing electrodes, gas injection and tunable-energy NBs. Google’s machine learning framework for experimental optimization has also been routinely used to enhance plasma performance. D

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Employing a Narrow-Band-Gap Mediator in Ternary Solar Cells for Enhanced Photovoltaic Performance

Ternary organic solar cells (OSCs) provide a convenient and effective means to further improve the power conversion efficiency (PCE) of binary ones via composition control. However, the role of the third component remains to be explored in specific binary systems. Herein, we report ternary blend solar cells by adding the narrow-band-gap donor PCE10 as the mediator into the PBDB-T:IDTT-T binary blend system. The extended absorption, efficient fluorescence resonance energy transfer, enhanced charge dissociation, and induced tighter molecular packing of the ternary blend films enhance the photovoltaic properties of devices and deliver a champion PCE of 10.73% with an impressively high open-circuit voltage (VOC) of 1.03 V. Good miscibility and similar molecular packing behavior of the components guarantee the desired morphology in the ternary blend films, leading to solar cell devices with over 10% PCEs at a range of compositions. Our results suggest that ternary systems with properly aligned energy levels and overlapping absorption among the components hold great promises to further enhance the performance of corresponding binary ones.

14 SOLAR ENERGY↗
DOE OSTI2026

Enhanced electrochemical performance and extended cycling of resorcinol-formaldehyde derived N-doped carbon xerogel for alkali metal-ion (Li/Na/K) batteries

Resorcinol formaldehyde-derived carbon xerogel (RFC) is a versatile material with tuneable properties, synthesized through a simple sol-gel method. This study presents nitrogen-doped RF carbon xerogel (N-RFC) with 11.8 at% nitrogen doping, offering a microporous architecture ideal for alkali metal-ion (Li, Na, K) batteries. The porous N-doped framework enhances electrochemical performance by improving ion transport, increasing active storage sites, and significantly boosting metal-ion adsorption, particularly through pyrrolic nitrogen, as revealed by first-principles calculations supported by XPS analysis. N-RFC anodes showed excellent cycling stability, high-capacity retention, and fast charge/discharge capabilities, rendering them suitable for commercial applications. Notably, the N-RFC anode demonstrates high-rate long-term cycling stability, retaining its capacity of 83.5 % (188 mAh/g at 2 C-rate) and 50 % (133 mAh/g at 1250 mA/g) over 1000 cycles for Li and Na-ion batteries, respectively, favorable for commercial battery applications. Additionally, N-RFC demonstrates a reversible capacity of 120 mAh/g after 394 cycles with a retention of 82 % for K-ion batteries. The ability of the material to accommodate larger ions like Na + and K + further emphasizes its versatility and potential application in diverse alkali metal-ion battery systems.

25 ENERGY STORAGE↗
DOE OSTI2021

Enhancing membrane performance for CO 2 capture from flue gas with ultrahigh MW polyvinylamine

Membranes for post-combustion CO 2 capture are required to have a high CO 2 permeance due to the limited driving force. For facilitated transport membranes synthesized with polyvinylamine (PVAm), a defect-free selective layer of <200 nm is usually required to render sufficient permeance with high CO 2 /N 2 selectivity. In order to meet such a demand through the knife-coating process, the coating solution needs to have a high viscosity at a relatively low concentration to minimize its penetration into the substrate. The demand was met by synthesizing PVAm with an ultrahigh molecular weight (MW) via inverse emulsion polymerization (IEP) in this study. Compared to solution polymerization, IEP isolates the reaction in inverse micelles suspended in a continuous organic phase, which allows excellent dissipation of the heat generated by the reaction and reduces gel formation drastically. The polymerization parameters, including monomer concentration, initiator concentration, and reaction temperature, were investigated to obtain the optimal MW of PVAm for membrane performance. As compared to solution polymerization, IEP enhanced the MW of PVAm from 1.2 to 12.7 MDa, which minimized the penetration of the coating solution into the substrate and hence the extra mass transfer resistance. The effect of MW and degree of hydrolysis of PVAm on the membrane transport properties were studied. Furthermore, by employing PVAm with a MW of 12.7 MDa to strengthen the polymer matrix, the loading of piperazine glycinate in the membrane was increased up to 85 wt.%. In conclusion, the resultant membrane achieved a CO 2 permeance of 839 GPU and a CO 2 /N 2 selectivity of 161 at the typical flue gas temperature of 57°C.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2021

Extraordinary role of Zn in enhancing thermoelectric performance of Ga-doped n-type PbTe

Although Ga doping can weaken the electron phonon coupling in n-type PbTe, Ga-doped PbTe has a relatively low carrier concentration (n) and high lattice thermal conductivity (κ lat ), resulting in a lower figure of merit (ZT) compared with those of other top-performing n-type PbTe-based thermoelectric materials. Herein, we report the extraordinary role of Zn in enhancing the thermoelectric performance of Ga-doped PbTe. It is discovered that Zn can simultaneously improve the electronic transport properties and decrease the κlat of Ga-doped PbTe, thereby affording a record high ZT avg ~ 1.26 at 400–873 K, with a maximum ZT value of 1.55 at 723 K. The isoelectronic substitution of Zn for Pb in Ga-doped PbTe increases the electrical conductivity and n by inducing the nucleation and growth of Ga 2 Te 3 in the second phase. The formation of Ga 2 Te 3 results in nonstoichiometry and Te deficiency in the PbTe matrix, which increases the number of electron carriers. Additionally, discordant Zn and Ga atoms with displacing off-center from the ideal octahedral positions, as well as Ga 2 Te 3 nanocrystals ranging from 30 to 200 nm coherently embedded into the PbTe matrix effectively weaken the phonon modes and scatter heat-carrying phonons, resulting in a significant reduction in κ lat .

36 MATERIALS SCIENCE↗
DOE OSTI2020

Strong Valence Band Convergence to Enhance Thermoelectric Performance in PbSe with Two Chemically Independent Controls

We present an effective approach to favorably modify the electronic structure of PbSe using Ag doping coupled with SrSe or BaSe alloying. The Ag 4d states make a contribution to in the top of the heavy hole valence band and raise its energy. The Sr and Ba atoms diminish the contribution of Pb 6s2 states and decrease the energy of the light hole valence band. This electronic structure modification increases the density-of-states effective mass, and strongly enhances the thermoelectric performance. Furthermore, the Ag-rich nanoscale precipitates, discordant Ag atoms, and Pb/Sr, Pb/Ba point defects in the PbSe matrix work together to reduce the lattice thermal conductivity, resulting a record high average ZT avg of around 0.86 over 400–923 K.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Strong Valence Band Convergence to Enhance Thermoelectric Performance in PbSe with Two Chemically Independent Controls

Abstract We present an effective approach to favorably modify the electronic structure of PbSe using Ag doping coupled with SrSe or BaSe alloying. The Ag 4d states make a contribution to in the top of the heavy hole valence band and raise its energy. The Sr and Ba atoms diminish the contribution of Pb 6s 2 states and decrease the energy of the light hole valence band. This electronic structure modification increases the density‐of‐states effective mass, and strongly enhances the thermoelectric performance. Moreover, the Ag‐rich nanoscale precipitates, discordant Ag atoms, and Pb/Sr, Pb/Ba point defects in the PbSe matrix work together to reduce the lattice thermal conductivity, resulting a record high average ZT avg of around 0.86 over 400–923 K.

Luo, Zhong‐Zhen↗
DOE OSTI2021

Enhanced biomechanical performance of additively manufactured Ti-6Al-4V bone plates

As the global trauma fixation devices market expands rapidly, it is imperative to improve the production of fixation devices through enhanced design accuracy and fit for best performance and maximum patient comfort. Selective laser melting (SLM) is one of the mature additive manufacturing methods, which provides a viable route for the rapid production of such devices. In this work, the ability of SLM to produce near-net-shape parts, as desired for medical implants, was utilized for the fabrication of bone plates from Ti-6Al-4V alloy powder. Martensitic microstructure obtained after the printing of alloy resulted in poor ductility, limiting its application in the field of orthopedics. A specially designed repeated cyclic heating and cooling close to but below the β-transus was used to transform from acicular to a bimodal microstructure without the need for plastic deformation prior to heat treatment for improving the ductility. Bone plates subjected to this heat treatment were mechanically tested by means of tensile and 3-point bend tests and demonstrated large improvement in ductility, and the values were comparable to those similar plates prepared from wrought alloy. Other important properties required for implants were assessed, such as corrosion resistance in simulated body fluid and cytocompatibility in vitro using MC3T3-E1 cells. These results for the bone plate after heat treatment were excellent and similar to those of the additively manufactured and wrought plates. Taken together, the performance of the additively manufactured bone plates after subjecting to heat treatment was similar to those of bone plate manufactured using wrought alloy. These results have important implications for the fabrication of patient-specific metallic orthopedic devices using SLM without compromising their biomechanical performance by subjecting them to a tailored heat treatment.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Performance Testing of Enhanced Linear Variable Integrated Sensor (ELVIS III) for LVDTs

The Enhanced Linear Variable Intrinsic Sensor (ELVIS) was a 2024 breakthrough discovery by Idaho National Laboratory (INL) in terms of further innovating the usage of all linear variable differential transformers (LVDTs) and enhancing their performance in harsh environments. In irradiation tests conducted within material test reactors (MTRs), LVDTs with an internal temperature sensing capability can address several critical challenges. This report focuses on performance testing of the ELVIS III device with new hybrid LVDTs provided by the Institute for Energy Technology (IFE), which is the world’s sole supplier of nuclear-grade LVDTs. The ELVIS III device was evaluated in terms of temperature showcasing promising results comparable to a typical type-K thermocouple (TC).

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗
DOE OSTI2021

Functionalized Embedded Monometallic Nickel Catalysts for Enhanced Hydrogen Evolution: Performance and Stability

Viable anionic exchange membrane (AEM) electrolysis for H 2 production requires highly active hydrogen evolution reaction (HER) catalysts that are also robust and cost-effective. Traditionally juxtaposition of two transition metals with one being more oxophilic is necessary for easier access to water in the inner Helmholtz plane as a source of protons in the crucial Volmer step for enhanced HER activity. However, they are prone to passivation at anodic potentials or deactivation via the formation of sub-surface metal hydrides at high cathodic overpotentials. Here we report a method of enabling close juxtaposition of Ni-Ni-oxide surfaces by functionalizing Ni-based catalysts via the careful thermal treatment of carbon-supported Ni nano-particles chelated with a select organic chelating compound referred to as cupferron. This functionalization results in an embedded Ni surface with a clear graphitic coating engendering long-term stability for passivation and subsurface hydride formation. The stability and activity of the functionalized Ni catalyst are demonstrated in half-cell RDE and full-cell AEM membrane-based hydrogen pump experiments. In the case of the latter, the functionalized Ni outperforms carbon-supported Pt.

25 ENERGY STORAGE↗
DOE OSTI2024

Enable superior performance of ultra-high loading electrodes through the cost-efficient solvent-free electrode manufacturing technology

This research explores an innovative solvent-free method for fabricating ultra-high loading NMC811 and graphite electrodes (~6mAh∙cm -2 ), showcasing remarkable electrochemical performance enhancements compared to the electrodes prepared by the conventional slurry-casting method. Here, the optimized microstructure with dry-printed (DP) electrodes enhanced electrolyte penetration and minimized lithium-ion diffusion tortuosity resulting in improved rate performance at high current rates. Additionally, this innovative electrode manufacturing approach enables more uniform CEI and SEI formation and growth, which effectively doubles the cycle life of single-layer pouch cells with DP electrodes. Beyond the performance enhancements, this method also offers a notable 29.2 % overall cost advantages, potentially revolutionizing future battery manufacturing. The findings presented in this work underscore the potential of solvent-free manufacturing technology as a high-loading capable and cost-efficient path for advanced battery production.

25 ENERGY STORAGE↗
DOE OSTI2020

Laser-system model for enhanced operational performance and flexibility on OMEGA EP

The development of laser performance models having real-time prediction capability for the OMEGA EP laser system has been essential in meeting requests from its user community for increasingly complex pulse shapes that span a wide range of energies. The laser operations model PSOPS provides rapid and accurate predictions of OMEGA EP laser-system performance in both forward and backward directions, a user-friendly interface and rapid optimization capability between shots. We describe the model’s features and show how PSOPS has allowed real-time optimization of the laser-system configuration in order to satisfy the demands of rapidly evolving experimental campaign needs. We also discuss several enhancements to laser-system performance accuracy and flexibility enabled by PSOPS.

42 ENGINEERING↗
DOE OSTI2021

Origin of the enhanced Nb3Sn performance by combined Hf and Ta doping

Abstract In recent years there has been an increasing effort in improving the performance of Nb 3 Sn for high-field applications, in particular for the fabrication of conductors suitable for the realization of the Future Circular Collider (FCC) at CERN. This challenging task has led to the investigation of new routes to advance the high-field pinning properties, the irreversibility and the upper critical fields ( H Irr and H c2 , respectively). The effect of hafnium addition to the standard Nb-4Ta alloy has been recently demonstrated to be particularly promising and, in this paper, we investigate the origins of the observed improvements of the superconducting properties. Electron microscopy, Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS) and Atom Probe Tomography (APT) characterization clearly show that, in presence of oxygen, both fine Nb 3 Sn grains and HfO 2 nanoparticles form. Although EXAFS is unable to detect significant amounts of Hf in the A15 structure, APT does indeed reveal some residual intragrain metallic Hf. To investigate the layer properties in more detail, we created a microbridge from a thin lamella extracted by Focused Ion Beam (FIB) and measured the transport properties of Ta-Hf-doped Nb 3 Sn. H c2 (0) is enhanced to 30.8 T by the introduction of Hf, ~ 1 T higher than those of only Ta-doped Nb 3 Sn, and, even more importantly the position of the pinning force maximum exceeds 6 T, against the typical ~ 4.5–4.7 T of the only Ta-doped material. These results show that the improvements generated by Hf addition can significantly enhance the high-field performance, bringing Nb 3 Sn closer to the requirements necessary for FCC realization.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Effect of coherent edge-localized mode on transition to high-performance hybrid scenarios in KSTAR

This paper deals with one of the origins and trigger mechanisms responsible for the observed performance enhancements in the hybrid scenario experiments conducted in Korea Superconducting Tokamak Advanced Research (KSTAR). The major contribution to the performance improvement comes from a broader and higher pedestal formation. The increase of fast ion pressure due to a plasma density decrease also contributes substantially to the global beta. Although the reduced core plasma volume resulting from the pedestal expansion has a negative effect on the core thermal energy, a considerable confinement improvement observed in the inner core region limits the degradation. The one significant characteristic of high-performance discharges is the presence of Coherent Edge-localized Mode (CEM) activity. CEM is triggered during the pedestal recovery phase between typical ELM crashes and has been found to be related to the increase of particle and heat transport. It appears to underlie two commonly observed phenomena in high-performance hybrid scenario discharges in KSTAR; pedestal broadening and continuous density decrease. Despite the associated transport increase, CEM activities can induce performance enhancement. With the pedestal broadening, ELM crashes become delayed and weakened, which, in turn, allows for a higher pedestal. Moreover, the density decrease directly increases fast ion pressure by extending the beam-slowing-down time. The linear gyrokinetic analysis reveals that the increase of fast ions could initiate positive feedback loops, leading to the stabilization of Ion Temperature Gradient mode in the inner core region.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Multifunctional fiber-reinforced composites for passive sensing and energy harvesting with enhanced mechanical performance

Fiber-reinforced polymer composites (FRPCs) are valid alternatives to metals, especially in the aerospace industry, for their superior strength-to-weight ratio. FRPCs are generally manufactured by stacking layers of fibers and infusing them with epoxy-based adhesives to result in laminates. Such layer-by-layer structure often ensues a poor interlaminar property of the composites. Additionally, FRPCs can sustain complex damage modes because of their inherent anisotropic characteristics. For example, delamination can occur due to low-velocity impact at a subsurface level, which can result in premature catastrophic failures if undetected. Thus, structural monitoring is crucial to identify such damage. Point-based sensors (e.g., strain gauges, accelerometers, among many) can be embedded in the FRPCs for structural monitoring. However, their electrical power demand often embroils their usage. Therefore, the main objective of this research is to design and implement multifunctional composites that can simultaneously perform passive sensing and energy harvesting while exhibiting better mechanical performance. Previous research efforts have demonstrated that a continuous feed-through deposition of functional materials on fiber surfaces simultaneously enhanced the mechanical and sensing properties of the FRPCs. This study explores a similar approach to encode passive sensing and energy harvesting properties in the FRPCs by integrating ferroelectric microparticles on the fiber surfaces. Upon ensuring their superior interlaminar shear strength, sensing and energy harvesting properties were characterized through experimental studies. The outcome is a multifunctional composite fabricated by coating the fibers with functional microparticles through a high throughput, scalable, and low-cost approach that enables passive sensing, energy harvesting, and improved mechanical performance.

Gupta, Sumit↗
DOE OSTI2025

Surface modification of cathode material enhances electrochemical performance in dry-processed Li-ion battery electrodes

The transition to electric vehicles (EVs) is pivotal for achieving energy security and integrating grid stability, with lithium-ion batteries (LIBs) playing a central role in this transformation. However, the conventional wet electrode manufacturing relying on N-methyl-2-pyrrolidone (NMP) solvent is energy intensive and costly. Dry processing (DP) has emerged as a promising alternative, eliminating solvents and using polytetrafluoroethylene (PTFE) binder for electrode fabrications. Despite its advantages, DP faces a critical challenge: poor interfacial adhesion between the hydrophobic PTFE binder and the hydrophilic cathode active material (CAM), particularly LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811), which undermines electrode performance. Here, to address this, we introduced a novel vapor-phase trimethoxymethylsilane (TMMS) coating to hydrophobize the CAM surface, enhancing compatibility with PTFE. This surface modification significantly enhances binder – CAM interactions, enabling uniform mixing and robust electrode integrity without damaging the CAM particles. Our findings advance the feasibility of environmentally sustainable and cost-effective dry processing, representing a significant step toward sustainable battery manufacturing.

Choi, Junbin [Oak Ridge National Laboratory (ORNL)↗