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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

A Robust, Scalable Platform for the Electrochemical Conversion of CO 2 to Formate: Identifying Pathways to Higher Energy Efficiencies

This work demonstrated a robust, scalable cell architecture for electroreduction of CO 2 (CO 2 R). An up to 90% faradaic efficiency for the conversion of CO 2 R to formate at 500 mA/cm 2 was realized at a 25 cm2 gas diffusion electrode (GDE) with a carbon-supported SnO 2 electrocatalyst. Furthermore, a 1.27 mm thick catholyte was used between the bipolar membrane and cathode GDE, which could be further reduced to tens of micrometers upon refinement. The deconvolution of the potential drop from each individual component/process guides the pathways to higher energy efficiencies of CO 2 R at this platform. Significant changes in the agglomerate size and aspect ratio on the electrode before and after an 11 h test were revealed by nano-CT, suggesting reduced CO 2 accessibility from electrode degradation. The versatility of this CO 2 R testing platform enables the ability to assess materials, components, and interactions at scales more in line with future devices.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Surpassing the Organic Cathode Performance for Lithium-Ion Batteries with Robust Fluorinated Covalent Quinazoline Networks

Organic electrode materials have promising application prospects in energy storage, but issues including rapid capacity fading and poor power capacity restrict their practical applications. In this study, nanoporous fluorinated covalent quinazoline networks (F-CQNs) were constructed by condensation of fluorinated aromatic aminonitrile precursors via an ionothermal pathway. Precise control of the reaction parameters afforded F-CQN-1-600 material featuring high surface area, permanent porosity, high nitrogen content (23.49 wt %), extended π-conjugated architecture, layered structure, and bipolar combination of benzene and tricycloquinazoline. Synergy among these unique properties leads to a good performance as a cathode source for lithium-ion batteries (LIBs) in terms of high capacity (250 mA h g –1 at 0.1 A g –1 ), high rate capability (105 mA h g –1 at 5.0 A g –1 ), and impressive cycling stability (95.8% retention rate after 2000 cycles at 2.0 A g –1 together with a high Coulombic efficiency of 99.95%), surpassing most of the previous organic cathode counterparts.

25 ENERGY STORAGE↗
DOE OSTI2022

Electrolytic Methane Production from Reactive Carbon Solutions

Here, we report an electrochemical reactor that converts 3.0 M KHCO 3 into methane at the cathode, and oxidizes water at the anode. The molar ratio of methane product to unreacted CO 2 gas (defined herein as "methane yield") was measured to be 34% at a partial current density of 120 mA cm -2 . The highest previously reported CO 2 -to-methane yield is 3%. Our reactor achieved this improvement in methane yield because it is fed with 3.0 M KHCO 3 , a type of reactive carbon solution, rather than gaseous CO 2 . The reactor uses H + delivered by a bipolar membrane to form CO 2 at the cathode. This CO 2 is subsequently reduced into methane. A cationic surfactant added to the catholyte suppressed hydrogen evolution and increased methane formation. A 1D continuum model confirmed that H + from the membrane promotes the formation of methane over multicarbon products at the cathode. These findings present design principles for electrochemical methane synthesis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

An Electrochemical Hydrogen-Looping System for Low-Cost CO 2 Capture from Seawater

Carbon dioxide (CO 2 ) capture from seawater is a viable, long-term solution for addressing legacy carbon pollution on the planet. However, significant challenges to widespread applicability exist in terms of efficiency, cost, and scalability. In this work, we have developed an electrochemical hydrogen-looping (EHL) system that capitalizes on the generation of proton and OH – from seawater. A CO 2 capture efficiency as high as 91% is achieved for our EHL flow cell. We have demonstrated that the electrochemical hydrogen-looping flow cell can remove CO 2 from simulated seawater at a record low electric energy consumption of 660 kWh ton –1 CO 2 , which is a significant reduction of 56% compared with the currently used bipolar membrane electrodialysis technology. In conclusion, the electrochemical hydrogen-looping flow cell with its much lower energy consumption provides an economical approach for direct removal of CO 2 from seawater at practical scale.

Electrical energy↗
DOE OSTI2022

Membrane Strategies for Water Electrolysis

Hydrogen holds great promise as a clean energy resource to help the global carbon-free energy goal. Here, green hydrogen production from renewable energy-powered water electrolysis can decarbonize hard-to-abate industries and transport applications. Ion-exchange membranes are an essential component of membrane-based water electrolysis, enabling high hydrogen production efficiency through a zero-gap configuration. While perfluorosulfonic acids are the standard polymer electrolyte membrane material, research efforts for membrane alternatives have increased over the years to drive down the cost of electrolyzers and improve devices’ durability without sacrificing performance and efficiency. Here we present our perspectives on acidic, alkaline, and bipolar membranes for water electrolyzers and discuss future research directions to develop advanced membranes for green hydrogen production technology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Modulating Solvation Structure in Concentrated Aqueous Organic Redox Flow Battery Electrolyte for Solubility and Transport Enhancement via Polycomplex Ion

Aqueous organic redox flow batteries hold great promise as a technology for creating economical grid energy storage using sustainable materials. Nonetheless, the solubility limit presents a universal barrier for all redox-active organic molecules. In this paper, a new approach is proposed to surpass the solubility limit by manipulating the solvation structure with polycomplex ion additives (PIA). Using poly(3,4-ethylenedioxythiophene) polystyrenesulfonate colloids as one example, its role in dismantling the rigid supramolecular clusters within the highly concentrated 7,8-dihydroxyphenazine-2-sulfonic acid electrolyte is investigated. 1 H and 23 Na NMR spectra and molecular dynamics simulation studies demonstrate that the bipolar structure of the PIA effectively disrupts the aggregations of DHPS and Na + ion in the highly concentrated anolyte, thus rendering a more flexible solvation structure and less restrictive ion transport, leading to substantially improved battery performance of an AORFB cell. The anolyte with PIA achieved 1.6 M and 74.3 Ah L –1 anolyte energy capacity.

25 ENERGY STORAGE↗
DOE OSTI2020

Local Environment Affects the Activity of Enzymes on a 3D Molecular Scaffold

The ability to coordinate and confine enzymes presents an opportunity to affect their performance and to create chemically active materials. Recent studies show that polymers and biopolymers can be used to scaffold enzymes, and that can lead to the modulated biocatalytic efficiency. In this work, we investigated the role of microenvironments on enzyme activity using a well-defined molecular scaffold. An enzyme, glucose oxidase (GO x ), was positioned at different locations of a three-dimensional (3D) octahedral DNA scaffold (OS), allowing the enzyme’s polyanionic environments to be altered. Using electrical sensing, based on a bipolar junction transistor, we measured directly and in real-time the enzyme’s proton generation at these different microenvironments. We found a 200% enhancement of immobilized enzyme over free GOx and about a 30% increase in catalytic rates when the enzyme was moved on the same molecular scaffold to a microenvironment with a higher local concentration of polyanions, which suggests a role of local pH on the enzymatic activity.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2023

Modeling the Charge and Exciton Distributions in Phosphorescent White Organic Light-Emitting Diodes

A comprehensive numerical model is developed to quantitatively analyze the charge and exciton distributions in phosphorescent white organic light emitting diodes (WOLEDs). The model encompasses bipolar charge drift-diffusion transport with doping-dependent charge mobilities, field-dependent charge hopping across multiple interfaces, exciton generation, diffusion, energy transfer, radiative decay, and non-radiative exciton annihilation. The model is validated by direct measurement of the exciton distribution in monochromatic phosphorescent OLEDs. It is then applied to complex, multilayer WOLEDs where it is used to accurately predict their intensity and current-dependent spectral shifts. The magnitudes of different exciton loss channels in WOLEDs are calculated and quantitatively compared. This model provides an alternative for the many experimental iterations commonly used to optimize the color balance of complex OLEDs. In this context, the model inspired the addition of a hole blocking layer in the WOLED to balance the charge conduction and reduce spectral shifts – a design that is verified by experiment.

42 ENGINEERING↗
DOE OSTI2025

Lithium Recovery and Conversion from Wastewater Produced by Recycling of Li-Ion Batteries via Two-Stage Electrodialysis

Electrodialysis (ED) is a membrane separation technique that has been well-established in various applications such as desalination, drinking water production, wastewater treatment, and lithium salt production. A limited number of studies have explored its application in lithium salt production, especially from secondary resources like wastewater. This study investigated a route to recover lithium from wastewater generated from the recycling of end-of-life Li-ion batteries. Two electrodialysis methods, namely standard electrodialysis (ED) and bipolar-membrane electrodialysis (BPED), were combined to concentrate lithium ions and convert them to lithium hydroxide (LiOH), a valuable product that can be fed back into the supply chain for manufacturing Li-ion batteries. Lithium (Li⁺) concentration in recycling wastewater was successfully increased by 58% using ED and converted to LiOH (>96% purity) with a further increase in Li⁺ concentration by 67% using BPED. The Coulombic efficiency of the experiments was 91.0 and 92.2%, with specific energy consumption of 1 and 2.5 kWh/kg, and a production rate of 1.01 and 0.14 kg/h/m 2 for the ED and BPED processes, respectively. In addition, preliminary techno-economic and environmental impact analyses show a significant improvement (GHG emission reduction by 77% and total energy reduction by 53%) by producing LiOH via electrodialysis compared to conventional lithium production via brine extraction. The process was assessed to be beneficial for lithium extraction from secondary resources and to enhance overall battery recycling efforts.

25 ENERGY STORAGE↗
DOE OSTI2020

A Retrospective of Findings From the FORTE Satellite Mission

We revisit the findings from the FORTE satellite program (1997–2004), which collected optical imaging of lightning as well as optical and radio frequency time series waveforms globally from low-earth-orbit. These include surveys of the earth's radio frequency anthropogenic noise environment; earth surface reflectivity at radio frequencies; a scheme for classifying lightning discharge types on the basis of their very high frequency time domain power envelope; insights into the polarization and radiation pattern characteristics of different lightning types, with implications for the underlying discharge processes; and estimates of cloud optical properties based on the statistics of scattered light. Most significantly, FORTE was uniquely suited to capture large samples of data from the rare discharge known as “narrow bipolar events,” enabling detailed examination of their basic characteristics and confirming that they appear to result from fundamentally distinct physical processes compared to other lightning. In particular, despite representing huge charge transfer they evidently produce little-to-no light output.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Statistical Properties of Magnetic Structures and Energy Dissipation during Turbulent Reconnection in the Earth's Magnetotail

Here, we present the first statistical study of magnetic structures and associated energy dissipation observed during a single period of turbulent magnetic reconnection, by using the in situ measurements of the Magnetospheric Multiscale mission in the Earth's magnetotail on 26 July 2017. The structures are selected by identifying a bipolar signature in the magnetic field and categorized as plasmoids or current sheets via an automated algorithm which examines current density and plasma flow. The size of the plasmoids forms a decaying exponential distribution ranging from subelectron up to ion scales. The presence of substantial number of current sheets is consistent with a physical picture of dynamic production and merging of plasmoids during turbulent reconnection. The magnetic structures are locations of significant energy dissipation via electric field parallel to the local magnetic field, while dissipation via perpendicular electric field dominates outside of the structures. Significant energy also returns from particles to fields.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Combined Optical and Radio-Frequency Perspectives on a Hybrid Cloud-To-Ground Lightning Flash Observed by the FORTE Satellite

In this work, we use the coincident optical and radio-frequency (RF) measurements taken by the Fast On-orbit Recording of Transient Events (FORTE) satellite to shed light on common optical signatures recorded by NASA and NOAA lightning imagers during Cloud-to-Ground (CG) lightning. We build flash cluster data for FORTE using the same techniques as the NASA/NOAA instruments to document the optical/RF evolution of an oceanic hybrid -CG flash. The flash began with strong Very High Frequency (VHF)-band emission from a Narrow Bipolar Event (NBE) that initiated a period of normal bilevel intracloud (IC) activity in two vertical layers (8 and 12 km) that lasted for 490 ms. VHF waveforms show step leader activity ahead of the return stroke. All impulsive VHF sources after the stroke come from the lower (8 km) layer. K-changes are noted following the return stroke, but no subsequent strokes are detected. The optical flash began 136 ms after the NBE RF pulse. Twenty-two of the 33 optical groups were dim and occurred during the in-cloud phase of the flash. This activity included both isolated pulses and sustained periods of illumination over tens of milliseconds. Initial cloud pulses accounted for 23% of the total optical radiance from the flash. Illumination during the return stroke contributed 58% of the total radiance, and the K-changes and cloud pulses after the stroke supplied the remaining 19%. These results highlight the benefit of having RF alongside optical lightning measurements for clarifying signatures in the optical data and providing information on their physical origins.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Solar, Atmospheric, and Volcanic Impacts on 10 Be Depositions in Greenland and Antarctica During the Last 100 Years

Cosmogenic radionuclides (e.g., 10 Be) from ice cores are a powerful tool for solar reconstructions back in time. However, superimposed on the solar signal, other factors like weather/climate and volcanic influences on 10 Be can complicate the interpretation of 10 Be data. A comprehensive study of 10 Be records over the recent period, when atmospheric 10 Be production and meteorological conditions are relatively well-known, can improve our interpretation of 10 Be records. Here we conduct a systematic study of the production and climate/volcanic signals in Antarctica and Greenland 10 Be records, including a new 10 Be record from the East GReenland Ice-core Project site. Greenland and Antarctica records show significant decreasing trends (5%–6.5%/decade) for 1900–1950, which is comparable with the expected production rate inferred from sunspot observations. By comparing 10 Be records with reanalysis data and atmospheric circulation patterns, 10 Be records from Southern/Southeastern Greenland are significantly correlated with the Scandinavia pattern. Stacking 10 Be records from different locations can enhance the production signal. However, this approach is not always straightforward as uncertainties in some records can lead to a weaker solar signal. A strategy can be employed to select records for the bipolar stack by comparing Greenland records with Antarctica records, assuming the shared signal is a production signal. Finally, we observe significant increases (36%–64%) in 10 Be depositions in Greenland related to the Agung eruption. This large increase in Greenland 10 Be records after the Agung eruption, could be partly explained by the enhanced air mass transport from mid-latitudes coinciding with the decreased precipitation en-route.

10Be↗
DOE OSTI2025

Observation of a Knotted Electron Diffusion Region in Earth's Magnetotail Reconnection

Magnetic reconnection is a fundamental plasma process that alters the magnetic field topology and releases magnetic energy. Most numerical simulations and spacecraft observations assume a two‐dimensional diffusion region, with the electron diffusion region (EDR) embedded in the same plane as the ion diffusion region (IDR) and a uniform guide field throughout. Using observations from Magnetospheric Multiscale mission, we report a non‐coplanar, knotted EDR in Earth's magnetotail current sheet. The reconnection plane of the knotted EDR deviates by approximately 38° from that of the IDR, with the guide field exhibiting both a 38° directional shift and a twofold increase in amplitude. Moreover, the Hall magnetic field is bipolar in the EDR but quadrupolar in the IDR, indicating different Hall current structures at electron and ion scales. These observations highlight the importance of three‐dimensional effects and illustrate the complexity of multiscale coupling between the EDR and IDR during reconnection studies.

diffusion region↗
DOE OSTI2026

Terrestrial Gamma‐Ray Flash Following Intense Negative Return Stroke Observed With BIMAP‐3D

We report ground-based observations of a terrestrial gamma-ray flash (TGF) associated with a strong negative cloud-to-ground lightning strike (-CG) which occurred near Los Alamos National Laboratory (LANL) in New Mexico, USA. Gamma photons were detected by the Terrestrial High-energy Observations of Radiation (THOR) instrument, developed at the University of California, Santa Cruz, which has been hosted at LANL since 2022. Simultaneous measurements were also made with the 3-Dimensional Broadband Interferometric Mapping and Polarization (BIMAP-3D) system, which includes 3D lightning mapping, two fast antennas, and an additional plastic scintillator. Additional field change waveforms were obtained from the Earth Networks Total Lightning Network (ENTLN). The lightning initiated about 1 km above the ground, leading to a powerful -CG with an ENTLN peak current of −237 kA and bipolar field change matching the recently described “energetic compact stroke” (ECS) shape. The TGF was then observed ∼35 µs after the start of the return stroke. We also observe an electric field pulse likely produced by the TGF either in isolation or by coupling to the lightning channel. Based on modeling of the radiated electric field and photon propagation through the atmosphere we infer that the TGF source was on the order of 1⁢0 17 photons. This TGF and associated lightning are extremely similar to some recently reported ECS TGFs in coastal Japan in winter, but we report the first observation of this phenomenon outside of Japan in a different climate, terrain, and season.

58 GEOSCIENCES↗
DOE OSTI2023

A scalable membrane electrode assembly architecture for efficient electrochemical conversion of CO2 to formic acid

Abstract The electrochemical reduction of carbon dioxide to formic acid is a promising pathway to improve CO 2 utilization and has potential applications as a hydrogen storage medium. In this work, a zero-gap membrane electrode assembly architecture is developed for the direct electrochemical synthesis of formic acid from carbon dioxide. The key technological advancement is a perforated cation exchange membrane, which, when utilized in a forward bias bipolar membrane configuration, allows formic acid generated at the membrane interface to exit through the anode flow field at concentrations up to 0.25 M. Having no additional interlayer components between the anode and cathode this concept is positioned to leverage currently available materials and stack designs ubiquitous in fuel cell and H 2 electrolysis, enabling a more rapid transition to scale and commercialization. The perforated cation exchange membrane configuration can achieve >75% Faradaic efficiency to formic acid at <2 V and 300 mA/cm 2 in a 25 cm 2 cell. More critically, a 55-hour stability test at 200 mA/cm 2 shows stable Faradaic efficiency and cell voltage. Technoeconomic analysis is utilized to illustrate a path towards achieving cost parity with current formic acid production methods.

08 HYDROGEN↗
DOE OSTI2025

Ampere-level co-electrosynthesis of formate from CO 2 reduction paired with formaldehyde dehydrogenation reactions

Current catalysts face challenges with low formate selectivity at high current densities during the CO 2 electroreduction. Here, we showcase a versatile strategy to enhance the formate production on p-block metal-based catalysts by incorporating noble metal atoms on their surface, refining oxygen affinity, and tuning adsorption of the critical oxygen-bound *OCHO intermediate. The formate yield is observed to afford a volcano-like dependence on the *OCHO binding strength across a series of modified catalysts. The rhodium-dispersed indium oxide (Rh/In 2 O 3 ) catalyst exhibits impressive performances, achieving Faradaic efficiencies (FEs) of formate exceeding 90% across a broad current density range of 0.20 to 1.21 A cm −2 . In situ Raman spectroscopy and theoretical calculations reveal that the oxophilic Rh site facilitates *OCHO formation by optimizing its adsorption energy, placing Rh/In 2 O 3 near the volcano-shaped apex. A bipolar electrosynthesis system, coupling the CO 2 reduction at the cathode with the formaldehyde oxidative dehydrogenation at the anode, further boosts the FE of formate to nearly 190% with pure hydrogen generation under an ampere-level current density and a low cell voltage of 2.5 V in a membrane electrode assembly cell.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Field-resilient supercurrent diode in a multiferroic Josephson junction

The research on supercurrent diodes has surged rapidly due to their potential applications in electronic circuits at cryogenic temperatures. To unlock this functionality, it is essential to find supercurrent diodes that can work consistently at zero magnetic field and under ubiquitous stray fields generated in electronic circuits. However, a supercurrent diode with robust field tolerance is currently lacking. Here, we demonstrate a field-resilient supercurrent diode by incorporating a 2D multiferroic material into a Josephson junction, and observed a pronounced supercurrent diode effect at zero magnetic field. More importantly, the supercurrent rectification persists over a wide and bipolar magnetic field range beyond industrial standards for field tolerance. By theoretically modeling a multiferroic Josephson junction, we unveil that the interplay between spin-orbit coupling and multiferroicity underlies the unusual field resilience of the observed diode effect. This work introduces multiferroic Josephson junctions as a new field-resilient superconducting device for cryogenic electronics.

Yang, Hung-Yu [Univ. of California, Los Angeles, C↗