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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Vitamin-Mediated Glucose Flow Cell for Sustainable Power Generation

Glucose as biofuel asserts unique advantages, including low-temperature electricity generation, easy accessibility, low storage cost, and flexible application for on-demand power generation. Riboflavin, also known as Vitamin B 2 , is a critical component in biological systems and is involved in many metabolic reactions as enzyme cofactors. Inspired by these metabolic reactions, we demonstrate a flow cell for electrochemical glucose oxidation reaction (GOR), using riboflavin as an environmentally friendly mediator to replace traditional noble metal catalysts. When paired with O 2 under alkaline conditions, the glucose flow cell achieves a peak power density of 13 mW/cm 2 , 20 times higher than the previous report in alkaline conditions. The demonstrated vitamin-mediated engineered biofuel flow cell delivered high peak power density at room temperature/ambient pressure while maintaining low cost and environmental friendliness, eliminating the need for a noble metal catalyst.

electrolytes↗
DOE OSTI2022

Integration of Highly Luminescent Lead Halide Perovskite Nanocrystals on Transparent Lead Halide Nanowire Waveguides through Morphological Transformation and Spontaneous Growth in Water

The integration of highly luminescent CsPbBr 3 quantum dots on nanowire waveguides has enormous potential applications in nanophotonics, optical sensing and quantum communications. On the other hand, CsPb 2 Br 5 nanowires have also attracted a lot of attention due to their unique water stability and controversial luminescent property. Here we first report the growth of CsPbBr 3 nanocrystals on CsPb 2 Br 5 nanowires by simply immersing CsPbBr 3 powder into pure water, CsPbBr 3-γ X γ (X = Cl, I) nanocrystals on CsPb 2 Br 5-γ X γ nanowires are then synthesized for tunable light sources. Systematic structure and morphology studies, including in-situ monitoring, revealed that CsPbBr 3 powder was first converted to CsPb 2 Br 5 microplatelets in water, followed by a morphological transformation from CsPb 2 Br 5 microplatelets to nanowires, which is a kinetic dissolution-recrystallization process controlled by electrolytic dissociation and supersaturation of CsPb 2 Br 5 . CsPbB r3 nanocrystals are spontaneously formed on CsPb 2 Br 5 nanowires when nanowires are collected from the aqueous solution. Raman spectroscopy, combined photoluminescence and SEM imaging confirm that the bright emission originates from CsPbBr 3-γ X γ nanocrystals while CsPb 2 Br 5-γ X γ nanowires are transparent waveguides. In conclusion, the intimate integration of nanoscale light sources with a nanowire waveguide is demonstrated through the observation of the wave guiding of light from nanocrystals and Fabry-Perot interference modes of the nanowire cavity.

42 ENGINEERING↗
DOE OSTI2020

Accommodation of Silicon in an Interconnected Copper Network for Robust Li-Ion Storage

Silicon (Si)-based materials are one of the most promising anodes to be applied in rechargeable lithium ion batteries. However, the active Si/electrolyte interface causes continuous side reactions and poor conductivity, which significantly decreases the cycling stability. Cu is the only metallic current collector that has been known to promote electron conduction and lithium-ion transfer without alloying reaction occurrence. However, to the best current knowledge, scalable interface engineering incorporating Cu has not been reported. In this study, this conductive Cu interface (CCI) is constructed through a self-assembly carbothermic reduction method to achieve efficient protection of Si/electrolyte interfaces while allowing for fast Li + diffusion. The energy barrier of lithium-ion diffusion through Cu is calculated to be 0.1965 eV, which is much lower than that through Au, Fe, and Ni films. Benefiting from the enhanced interfacial protection and kinetics of Si with CCI, a fading rate of only 0.068% is maintained for 1000 cycles and an aerial capacity of 4.78 mAh cm -2 is achieved after 280 cycles, which is comparable to the industry standards required for practical application.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Feasibility of TEMPO-functionalized imidazolium, ammonium and pyridinium salts as redox-active carriers in ethaline deep eutectic solvent for energy storage

The discovery of electrolytes that have low vapor pressures and high solubility towards redox active species with an ability to undergo multiple electron transfer reactions is a challenge to realize in large-scale energy storage. In this work, we investigate the feasibility of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) derived halide salts as redox active species in ethaline (1 : 2 ethylene glycol : choline chloride), a deep eutectic solvent (DES). Hydrogen bonding and electrostatic interactions achieved by the functionalization of TEMPO are shown to improve solubility in ethaline. This is the first study evaluating the physical properties and electrochemical behavior of the newly synthesized TEMPO-salts in ethaline providing insight into the impact of chemical functionality on the utility of these redox active species in DESs.

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

Transport phenomena in electrolyte solutions: Nonequilibrium thermodynamics and statistical mechanics

The theory of transport phenomena in multicomponent electrolyte solutions is presented here through the integration of continuum mechanics, electromagnetism, and nonequilibrium thermodynamics. The governing equations of irreversible thermodynamics, including balance laws, Maxwell's equations, internal entropy production, and linear laws relating the thermodynamic forces and fluxes, are derived. Green–Kubo relations for the transport coefficients connecting electrochemical potential gradients and diffusive fluxes are obtained in terms of the flux–flux time correlations. Furthermore, the relationship between the derived transport coefficients and those of the Stefan–Maxwell and infinitely dilute frameworks are presented, and the connection between the transport matrix and experimentally measurable quantities is described. To exemplify the application of the derived Green–Kubo relations in molecular simulations, the matrix of transport coefficients for lithium and chloride ions in dimethyl sulfoxide is computed using classical molecular dynamics and compared with experimental measurements.

42 ENGINEERING↗
DOE OSTI2023

A conformal heat-drying direct ink writing 3D printing for high-performance lithium-ion batteries

High areal capacity electrodes hold great potential for high-energy density lithium-ion batteries (LIBs), but their poor electrochemical kinetics limit their power density. Here, in this study, high areal capacity 3D-structured LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathodes (4.3 mAh cm -2 ) are prepared via 3D printing with a manner of direct ink writing. The electrodes had an enlarged electrode–electrolyte contact area, shortened diffusion pathway, and reduced intercalation-induced stress, thereby delivering enhanced rate capability and cyclability in LIBs, which is 143.6 mAh g -1 at 3C and a 60.2 % capacity retention over 800 cycles at 1C. Moreover, at electrode level, the 3D-NMC exhibits an energy and power densities of 313.1 Wh kg -1 and 657.9 W kg -1 , respectively. Furthermore, the theoretical calculation suggests that reducing the gap width will be highly beneficial to the energy and power densities. This work establishes a milestone in understanding the cycling effect on the electrode local structure, including the void area and the LiNi 0.8 Mn 0.1 Co 0.1 O 2 region, which confirms the effectiveness of 3D printing for electrode preparation.

25 ENERGY STORAGE↗
NASA NTRS2013

NASA Tech Briefs, April 2013

Topics covered include: Fully Integrated, Miniature, High-Frequency Flow Probe Utilizing MEMS Leadless SOI Technology; Nanoscale Surface Plasmonics Sensor With Nanofluidic Control; Advanced Dispersed Fringe Sensing Algorithm for Coarse Phasing Segmented Mirror Telescopes; Neural Network Back-Propagation Algorithm for Sensing Hypergols; Bulk Moisture and Salinity Sensor; Change-Based Satellite Monitoring Using Broad Coverage and Targetable Sensing; Circularly Polarized Microwave Antenna Element with Very Low Off-Axis Cross-Polarization; Ultra-Low Heat-Leak, High-Temperature Superconducting Current Leads for Space Applications; Flash Cracking Reactor for Waste Plastic Processing; An Automated Safe-to-Mate (ASTM) Tester; Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch; Compute Element and Interface Box for the Hazard Detection System; DOT Transmit Module; Composite Aerogel Multifoil Protective Shielding; Li-Ion Electrolytes with Improved Safety and Tolerance to High-Voltage Systems; Polymer-Reinforced, Non-Brittle, Lightweight Cryogenic Insulation; Controlled, Site-Specific Functionalization of Carbon Nanotubes with Diazonium Salts; Regenerable Sorbent for CO2 Removal; Sprayable Aerogel Bead Compositions With High Shear Flow Resistance and High Thermal Insulation Value; Lexan Linear Shaped Charge Holder with Magnets and Backing Plate; Robotic Ankle for Omnidirectional Rock Anchors; Wind, Wave, and Tidal Energy Without Power Conditioning; An Active Heater Control Concept to Meet IXO Type Mirror Module Thermal-Structural Distortion Requirement; Waterless Clothes-Cleaning Machine; Integrated Electrical Wire Insulation Repair System; LVGEMS Time-of-Flight Mass Spectrometry on Satellites; Surface Inspection Tool for Optical Detection of Surface Defects; Per-Pixel, Dual-Counter Scheme for Optical Communications; Certification-Based Process Analysis; Surface Navigation Using Optimized Waypoints and Particle Swarm Optimization; Smart-Divert Powered Descent Guidance to Avoid the Backshell Landing Dispersion Ellipse; Estimating Foreign-Object-Debris Density from Photogrammetry Data; Adaptive Sampling of Spatiotemporal Phenomena with Optimization Criteria; Building a 2.5D Digital Elevation Model From 2D Imagery; Eyes on the Earth 3D; Target Trailing With Safe Navigation for Maritime Autonomous Surface Vehicles; Adams-Based Rover Terramechanics and Mobility Simulator - ARTEMIS; ISTP CDF Skeleton Editor; Uplink Summary Generator (ULSGEN) Version 1.0; Robotics On-Board Trainer (ROBoT); Software Engineering Tools for Scientific Models; Automatic Data Filter Customization Using a Genetic Algorithm; Tracker Toolkit; Towards Efficient Scientific Data Management Using Cloud Storage; On a Formal Tool for Reasoning About Flight Software Cost Analysis; A Nanostructured Composites Thermal Switch Controls Internal and External Short Circuit in Lithium Ion Batteries; Spacecraft Crew Cabin Condensation Control; and Functional Near-Infrared Spectroscopy Signals Measure Neuronal Activity in the Cortex.

Source record↗
DOE OSTI2020

Effect of isotropic and anisotropic porous microstructure on electrochemical performance of Li ion battery cathodes: An experimental and computational study

Liquid electrolyte mass transport is a major limitation affecting high-power Li ion batteries. Fast discharging causes Li salt depletion in the current collector region of the cathode which produces overpotential in the electrolyte and consequently a drop of cell voltage to below the cut-off voltage, especially at higher electrode thickness and discharge rate. In this study, through experiment and simulation, we have investigated the effect of electrode thickness, mass loading, discharge rate and tortuosity on electrolyte mass transport and final derived areal capacity and specific energy for electrodes having isotropic (normal tape casting) and anisotropic (freeze tape casting) porous microstructure. Furthermore, the macroporous channels in freeze tape cast electrodes facilitate Li salt transport and reduce the Li salt mass transport limitations even at high electrode thickness and discharge rates, and high electrode tortuosity. In our results, computer simulations show that freeze tape cast electrodes may be fully discharged up to 750 μm thickness at 1 C rate compared to 300 μm for normal tape cast electrodes with the same mass loading. Freeze tape cast electrodes also show stable maximum areal capacity for C rates about double the maximum C rates of their normal tape cast electrode counterparts with the same mass loading.

25 ENERGY STORAGE↗
DOE OSTI2023

CO 2 electroreduction favors carbon isotope 12 C over 13 C and facilitates isotope separation

We discovered that CO 2 electroreduction strongly favors the conversion of the dominant isotope of carbon ( 12 C) and discriminates against the less abundant, stable carbon 13 C isotope. Both absorption of CO 2 in the alkaline electrolyte and CO 2 electrochemical reduction favor the lighter isotopologue. As a result, the stream of unreacted CO 2 leaving the electrolyzer has an increased 13 C content, and the depletion of 13 C in the product is several times greater than that of photosynthesis. Using a natural abundance feed, we demonstrate enriching of the 13 C fraction to ~1.3% (i.e., +18%) in a single-pass reactor and propose a scalable and economically attractive process to yield isotopes of a commercial purity. Our finding opens pathways to both cheaper and less energy-intensive production of stable isotopes ( 13 C, 15 N) essential to the healthcare and chemistry research, and to an economically viable, disruptive application of electrolysis technologies developed in the context of sustainability transition.

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

Thermodynamic Origin of Reaction Non-Uniformity in Battery Porous Electrodes and Its Mitigation

The development of non-uniform reaction current distribution within porous electrodes is a ubiquitous phenomenon during battery charging/discharging and frequently controls the rate performance of battery cells. Reaction inhomogeneity in porous electrodes is usually attributed to the kinetic limitation of mass transport within the electrolyte and/or solid electrode phase. In this work, however, we reveal that it is also strongly influenced by the intrinsic thermodynamic behavior of electrode materials, specifically the dependence of the equilibrium potential on the state of charge: the electrode reaction becomes increasingly non-uniform when the slope of the equilibrium potential curve is reduced. We employ numerical simulations and equivalent circuit model to elucidate such a correlation and show that the degree of reaction inhomogeneity and the resultant discharge capacity can be predicted by a dimensionless reaction uniformity number. For electrode materials that have equilibrium potentials insensitive to the state of charge and exhibit significant reaction non-uniformity, we demonstrate several approaches to spatially homogenizing the reaction current inside porous electrodes, including matching the electronic and ionic resistances, introducing graded electronic conductivity and reducing the surface reaction kinetics.

25 ENERGY STORAGE↗
DOE OSTI2026

Alkali Cation-Mediated Modulation of CO 2 Reduction Activity on Tin Electrodes in [EMIM][BF 4 ]/H 2 O Electrolytes

The development of efficient CO 2 reduction technologies hinges upon a thorough understanding of the intricate interplay between solution cations and the characteristics of the electrode surface. Recently, ionic liquids (ILs) have emerged as promising electrolytes for the CO 2 reduction reaction. However, the effect of alkali cations on the electrochemical CO 2 reduction (CO 2 R) reaction remains unclear in ILs. Here, in this report, we studied alkali cation effects by assessing the electrocatalytic CO 2 R activity with the IL 1-ethyl-3-methylimidazolium tetrafluoroborate, [EMIM][BF 4 ], in water with alkali metal co-cations (i.e., Li + , Na + , and K + ) using a polycrystalline Sn catalyst. Contrary to previous findings in purely aqueous media with inorganic cations, where alkali cations strongly enhance CO 2 R via pH modulation and strengthening of interfacial electric fields, alkali cations in electrolytes containing the IL [EMIM][BF4] negatively impact CO 2 R activity on Sn electrodes. These results were attributed to the larger radius and higher concentration of the IL organic cation [EMIM] + that mitigates the impact of alkali cations. These findings highlight the complex interplay between IL cations and alkali metals in shaping CO 2 R performance.

Chemistry↗
DOE OSTI2021

Suppression of electroconvective and morphological instabilities by an imposed cross flow of the electrolyte

Electroconvective (EC) instability and its influence on surface morphological perturbations (Morph) are important in many applications, including electrodialysis, batteries, and fuel cells. In this work, we study the effects of a two-dimensional channel flow on the EC and Morph instabilities using two approaches. In the bulk analysis, we derive the asymptotic solutions for small and large wave numbers by neglecting the space charge layer and imposing a second kind electroosmosis slip velocity boundary condition on the electroneutral bulk region. In the full analysis, the instability of the entire region of the liquid electrolyte is analyzed using the ultraspherical spectral method. Both studies show that the flow significantly affects the EC instability. The imposed flow distorts the concentration field, causing a sheltering effect which hinders the ion transport from low- to high-concentration regions, and therefore suppresses the EC instability below a certain wave number. In combination with the viscous stabilization of the high wave number modes by the space charge layer, a sufficiently strong imposed flow can fully suppress the EC instability. The increment in the critical voltage for the instability onset is roughly proportional to the square root of the product of imposed velocity and double layer thickness. The imposed flow has a smaller effect on the Morph instability, except that it may remove the morphological modes resulting from the EC instability and thereby change the wave number of the most unstable mode.

42 ENGINEERING↗
DOE OSTI2021

Void-free Copper Electrodeposition in High Aspect Ratio, Full Wafer Thickness Through-Silicon Vias with Endpoint Detection

High density interconnects are required for increased input/output for microelectronics applications, incentivizing the development of Cu electrochemical deposition (ECD) processes for high aspect ratio through-silicon vias (TSVs). This work outlines Cu ECD processes for 62.5 μ m diameter TSVs, etched into a 625 μ m thick silicon substrate, a 10:1 aspect ratio. Cu ECD in high aspect ratio features relies on a delicate balance of electrolyte composition, solution replenishment, and applied voltage. Implementing a CuSO 4 -H 2 SO 4 electrolyte, which contains suppressor and a low chloride concentration, allows for a tunable relationship between applied voltage and localized deposition in the vias. A stepped potential waveform was applied to move the Cu growth front from the bottom of the via to the top. Sample characterization was performed through mechanical cross-sections and X-ray computed tomography (CT) scans. The CT scans revealed small seam voids in the Cu electrodeposit, and process parameters were tuned accordingly to produce void-free Cu features. During the voltage-controlled experiments, measured current data showed a characteristic current minimum, which was identified as an endpoint detection method for Cu deposition in these vias. We believe this is the first report of this novel endpoint detection method for TSV filling.

42 ENGINEERING↗
DOE OSTI2020

Atomic-Level Understanding of Surface Reconstruction Based on Li[Ni x Mn y Co 1–x–y ]O 2 Single-Crystal Studies

The stability of cathode particle surfaces that are directly exposed to the electrolyte is one of the most crucial and determining factors for cathode performance at high operating voltages. Theory has predicted a strong dependence of surface stability on chemical compositions as well as surface facets of layered oxides, yet conflicting results on the correlations exist as most experimental studies focus on cycled secondary particles recovered from composite electrodes. Here, we synthesize well-formed Li[Ni x Mn y Co 1–x–y ]O 2 (NMC) single-crystal samples, carefully define pristine surface properties, and then monitor their evolution with cycling. Atomic-resolution scanning transmission electron microscopy (STEM) imaging and electron energy loss spectroscopy (EELS) analysis show the formation of a surface reconstruction layer (SRL) as well as an extended surface reduction layer on pristine, Li-permeable non-(001) surfaces, even before cycling. We reveal a transition region with chemical gradient, in which the layered structure gradually densifies and eventually transforms into the SRL on the top surface. Contrary to these observations, no SRL is observed on pristine, Li-impermeable (001) surfaces, revealing the facet-dependent nature of surface reconstructions during particle synthesis. Upon electrochemical cycling, significant composition-and facet-dependent SRL growth is observed. The driving force and mechanism for surface reconstruction are further discussed. The present study provides insights into the origin as well as the nature of SRLs, highlighting the significance of surface engineering in cathode material optimization.

25 ENERGY STORAGE↗
DOE OSTI2021

International Meeting on Fuel Cell and Electrolyzer Quality Control: Summary Report

Quality control (QC) for both polymer electrolyte membrane fuel cell and electrolysis membrane electrode assembly (MEA) materials is a key challenge for scale-up and cost reduction. Developing methods for detecting defects, as well as measuring critical material properties and understanding the impact of as-manufactured variations in these materials on cell performance and lifetime, are critical barriers. To help address these needs, the National Research Council Canada (NRC), Fraunhofer Institute for Solar Energy Systems (ISE), and the National Renewable Energy Laboratory (NREL) have organized and facilitated a series of workshops on the topic, bringing together industry, academia, and research institutions from North America and Europe. Prior workshops in Canada and Germany have focused on the status of quality tool capabilities and identification of needed developments for fuel cells. These meetings have garnered an excellent response and follow-on attendance, with over 100 unique attendees.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2021

A novel solid oxide electrolytic cell with reduced endothermic load for CO 2 electrolysis using (La 0.80 Sr 0.20 ) 0.95 MnO 3-δ cathode

CO 2 conversion to CO via solid oxide electrolysis provides a potentially efficient method for converting CO 2 into an industrially relevant product. A solid oxide electrolysis cell with (La 0.80 Sr 0.20 ) 0.95 MnO 3-δ (LSM) as the CO 2 reduction cathode, yttrium stabilized zirconia (YSZ) as electrolyte, and nickel as the H 2 oxidation anode was operated 800 °C and 850 °C. Thermogravimetric analysis of the LSM material showed no catalyst oxidation at operating temperatures allowing for CO 2 electrolysis without reducing safe gas. In addition, no cathode material mass gain was observed in the presence of CO suggesting little to no carbon deposition occurred above 750 °C. The formation rates of CO for the cell reached 1.15 mL∙min-1∙ cm -2 for an applied current of 150 mA∙cm -2 achieving a faradaic efficiency of 100 %. Furthermore, the cell displayed good stability in the short-term CO 2 electrolysis test with a nominal voltage drop of 4 mV h -1 for 10 h at 850°C. This study shows the feasibility of operating a solid oxide CO 2 electrolysis cell for CO production with H 2 at the anode to reduce endothermic process load.

(La0.80Sr0.20)0.95MnO3-δ↗
DOE OSTI2020

Operando Acoustic Monitoring of SEI Formation and Long-Term Cycling in NMC/SiGr Composite Pouch Cells

Stable long-term cycling and solid-electrolyte-interphase (SEI) formation are key challenges in the design of Si/graphite composites as Li-ion battery (LIB) anode materials. Typically, these long-term cycling properties are examined in flooded half-cell settings making use of a Li-metal counter electrode and a Si/graphite working electrode. This form factor has the advantage of offering an unlimited supply of Li-ions and electrolyte, thus isolating performance degradation to the passivation of the working electrode. However, half-cell studies are ineffective in revealing performance and degradation mechanisms of the Si/graphite composite in a more commercially realistic full cell setting. This paper outlines an operando acoustic technique that can offer insights on SEI formation and capacity degradation of Si/graphite composites in a full cell setting. Through a combination of electrochemical and chemical analyses, we show that increasing passivation of the silicon particles in the Si/graphite composite anode is correlated with an increase in the acoustic time-of-flight shift. We further show that temporary loss of the acoustic signal during the first cycle is associated with significant gassing of the cell. The operando acoustic technique outlined here is low-cost, simple to setup and has the potential for localized resolution, indicating usefulness in commercial-scale Si/graphite cell quality control and diagnosis.

42 ENGINEERING↗
DOE OSTI2020

Tailoring a Three-Phase Microenvironment for High-Performance Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells

Despite tremendous progress in catalyst development for rate-limiting cathodic oxygen reduction reaction (ORR), reducing Pt usage while meeting performance requirements in practical proton exchange membrane fuel cells (PEMFCs) remains a challenge. The ORR in PEMFCs occurs at a catalyst–electrolyte–gas three-phase interface. A desirable interface should exhibit highly active and available catalytic sites, as well as allow efficient oxygen and proton feeding to the catalytic sites and timely removal of water to avoid interface flooding. In this work, we report the design of a three-phase microenvironment in PEFMCs, showing that carbon surface chemistry can be tuned to modulate its interaction with the ionomers and create favorable transport paths for rapid delivery of both reactants and products. With such an elaborate interfacial design, for the first time we have demonstrated PEMFCs with all key ORR catalyst performance metrics, including mass activity, rated power, and durability, surpassing the US Department of Energy targets.

25 ENERGY STORAGE↗