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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Effect of Cathode Cooling in Three-Dimensional Simulations of an Atmospheric Pressure Glow Discharge

The Atmospheric Pressure Glow Discharge (APGD) is a relatively simple and versatile plasma source used in a wide range of applications. Active cooling of the cathode can effectively mitigate instabilities, leading to glow-to-arc transitions. This study investigates the effect of varying the degree of cathode cooling in APGD with a planar cathode in helium. The plasma flow model incorporates mass conservation, chemical species transport, momentum conservation, conservation of thermal energy of heavy species and of electrons, and electrostatics. The model is applied to time-dependent simulations through a three-dimensional computational domain describing the whole discharge, without geometric symmetry or steady-state assumptions. Simulations of an experimentally characterized APGD explore the effects of electric current and cathode cooling—ranging from thermally insulated to extreme convective cooling. Results show the formation of an annular region with high electric field over the cathode surface under conditions of high current and low cooling.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Functional polymer binder for sulfur cathode fabrication

The present invention provides for a composition of matter, polymeric conductive binder, or electrode comprising: Poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)]. The present invention also provides for a Lithium-Sulfur (Li—S) battery comprising a cathode comprising: a cathode comprising a polymeric conductive binder poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)]; a separator; an anode; and, an electrolyte.

25 ENERGY STORAGE↗
DOE OSTI2026

All-organic self-separating three-dimensionally nanoarchitected electrochemical energy storage devices

This work realizes a three-dimensionally (3D) nanoarchitected, all organic, "self-separating" lithium-ion electrochemical energy storage (EES) device that is cycled as a solid-state full cell. The device is enabled by a monolithic carbon anode with a co-continuous pore network, derived from the structure direction of resols by an ultra-large molar mass block copolymer (BCP), poly(styrene-block-2-dimethylaminoethyl methacrylate) (SA). Electropolymerization of a single-phase conductive and redox-active material, poly((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methyl 9,10-dioxo-9,10-dihydroanthracene-2-carboxylate) (PAQEDOT), into the pore space provides the cathode of the cell. The device is electronically contacted to the relevant electrode network enabled by the co-continuous nature of each electrode. Electrochemical processing via cycling against external lithium in an electrolyte generates a solid electrolyte interphase (SEI) as a separator and lithiates the cell electrodes, after which the EES device is cycled in the solid state. While the full cell does not demonstrate high cyclability, the best full cell demonstrates a discharge capacity of 267 milliamp hours per gram (mAh/g). This work marks, to the best of knowledge of the authors, the first example of an all-organic materials derived 3D nanoarchitected EES device, as well as the first design of "self-separating" cell fabrication. Furthermore, generalization of the design to another co-continuous carbon form factor is demonstrated.

FOS: Physical sciences↗
DOE OSTI2021

Mechanistic Study of the Li–Air Battery with a Co 3 O 4 Cathode and Dimethyl Sulfoxide Electrolyte

The lithium–air battery, a powerful competitor to replace the traditional lithium-ion battery, has attracted increasing attention due to its extremely high theoretical energy density. However, its development is limited by the cathode and electrolyte properties, which should include high stability, conductivity, and electrocatalytic properties in oxygen-rich environments. Here, we employ a systematic first-principles study of Li–O 2 discharge and charge reactions on the Co 3 O 4 -based cathode with the assistance of dimethyl sulfoxide (DMSO) electrolyte. The structure, stability, and electronic properties of different surface reconstructions of the Co 3 O 4 (100) facet are investigated. In addition, the mechanisms and thermodynamic overpotentials of multi-step reactions between Li + /e – and O 2 are provided, where lithium suboxide products (Li 2 O 2 or Li 3 O 2 ) are formed on the different Co 3 O 4 (100) terminations. The solvation shell of Li + components in explicit DMSO solvent is investigated through ab initio molecular dynamics simulations. In general, we find that the Co 3 O 4 (100)-O (oxidized) surface is the most stable one under standard conditions, and the stable Li + solvation structure is found in a tetrahedral Li(DMSO) 4 + shell in the DMSO-based electrolyte. Moreover, in the system of the Co 3 O 4 (100)-O cathode and DMSO electrolyte, the solution model pathway is energetically favorable for the Li–O 2 discharge reaction. It provides a low constant overpotential of 0.17 V during a long-term discharging process, thus causing the final toroid Li 2 O 2 formation on the cathode. During the charging process, an overpotential of 0.36 V is required to rapidly decompose Li 2 O 2 .

25 ENERGY STORAGE↗
DOE OSTI2021

Heavily Tungsten–Doped Sodium Thioantimonate Solid–State Electrolytes with Exceptionally Low Activation Energy for Ionic Diffusion

A strategy for modifying the structure of solid-state electrolytes (SSEs) to reduce the cation diffusion activation energy is presented. Two heavily W-doped sodium thioantimonate SSEs, Na 2.895 W 0.3 Sb 0.7 S 4 and Na 2.7 W 0.3 Sb 0.7 S 4 are designed, both exhibiting exceptionally low activation energy and enhanced room temperature (RT) ionic conductivity; 0.09 eV, 24.2 mS/cm and 0.12 eV, 14.5 mS/cm. At –15 °C the Na 2.895 W 0.3 Sb 0.7 S 4 displays a total ionic conductivity of 5.5 mS/cm. Here, the 30 % W content goes far beyond the 10–12 % reported in the prior studies, and results in novel pseudo-cubic or orthorhombic structures. Calculations reveal that these properties result from a combination of multiple diffusion mechanisms, including vacancy defects, strongly correlated modes and excessive Na-ions. An all-solid-state battery (ASSB) using Na 2.895 W 0.3 Sb 0.7 S 4 as the primary SSE and a sodium sulfide (Na 2 S) cathode achieves a reversible capacity of 400 mAh g –1 .

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

Synthesis and Mg 2+ deintercalation in manganese spinel nanocrystals

Transition metal oxides are promising materials as cathodes for divalent batteries with high capacity under high voltage. A major challenge is the sluggish kinetics of intercalation of divalent cations into the oxide host. Tailoring of the size, composition and crystal structure of oxides is a necessary strategy to alleviate these barriers, which challenges our control of their synthesis. In this work, we selectively synthesize spinel-type Mg x Mn 3-x O 4 nanocrystals with different Mg/Mn ratios and investigate their ability to electrochemically shuttle Mg 2+ ions. Crystal-chemical characterization of the reaction outcomes was conducted with X-ray diffraction, X-ray absorption spectroscopy, electron microscopy, and elemental analysis. Both 5 nm thick MgMn 2 O 4 nanosheets and 10 nm Mg 0.41 Mn 2.59 O 4 nanocubes underwent reversible Mg 2+ deintercalation, yet no obvious reaction was observed in 60 nm Mg 1.2 Mn 1.8 O 4 nanocubes. Our results suggest that both the size of the spinel nanocrystals and the Mg/Mn ratios play a role in the observed behaviour. The advances in the synthesis of spinel oxide nanocrystals achieved, and their correlation with Mg 2+ deintercalation, pave the way toward the precise synthesis of multivalent cathode materials that fundamentally overcome barriers to practical application.

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

Phase Stability and Kinetics of Topotactic Dual Ca 2+ –Na + Ion Electrochemistry in NaSICON NaV 2 (PO 4 ) 3

Recent reports of reversible calcium plating and stripping have rekindled interest in the development of Ca-ion batteries (CIBs) as next-generation energy storage devices. This technology has the potential to overcome the limitations of conventional Li-ion batteries, but CIBs are plagued by a paucity of suitable cathode materials. To date, NaSICON-structured NaV 2 (PO 4 ) 3 has been demonstrated as a successful cathode candidate, exhibiting reversible (de)intercalation of 0.6 mol Ca 2+ along with stable cycling performance. However, a complex multiphase mixture forms on discharge so the Ca-ion charge storage mechanism in the NaSICON framework is poorly understood. Here in this work, we report on an investigation of the structure and/or Na + /Ca 2+ environment(s) of a variety of chemically prepared NaSICON Ca x Na y V 2 (PO 4 ) 3 phases which were characterized using synchrotron XRD, SEM-EDS, 23 Na NMR, and TEM. Highly calciated CaV 2 (PO 4 ) 3 , Ca 1.5 V 2 (PO 4 ) 3 , and CaNaV 2 (PO 4 ) 3 phases can be prepared at high temperature, but -unlike Ca 0.6 NaV 2 (PO 4 ) 3 -these materials are electrochemically inactive. To better understand the fundamental factors impacting successful Ca 2+ electrochemistry in this system, DFT was employed to examine the Ca x Na y V 2 (PO 4 ) 3 phase diagram and Ca 2+ diffusion mechanism. Theoretical insights show that phase separation into Na-rich and Ca-rich phases is a reason for the capacity limitation and demonstrate that Na + ions in the host materials assist the migration of neighboring Ca 2+ ions, enabling reversible electrochemistry in Ca x Na y V 2 (PO 4 ) 3 . This investigation of fundamental principles affecting reversible Ca 2+ (de)intercalation in Ca x Na y V 2 (PO 4 ) 3 allows for the development of design principles to enable the discovery of a variety of successful cathodes for CIBs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Eliminating the Imbalanced Mobility Bottlenecks via Reshaping Internal Potential Distribution in Organic Photovoltaics

The imbalanced carrier mobility remains a bottleneck for performance breakthrough in even those organic solar cells (OSCs) with recorded power conversion efficiencies (PCEs). Herein, a counter electrode doping strategy is proposed to reshape the internal potential distribution, which targets to extract the low mobility carriers at far end. Device simulations reveal that the key of this strategy is to partially dope the active layer with a certain depth, therefore it strengthens the electric field for low mobility carriers near counter electrode region while avoids zeroing the electric field near collection electrode region. Taking advantage of these, PCE enhancements are obtained from 15.4% to 16.2% and from 16.9% to 18.0%, respectively, via cathode p-doping and anode n-doping. Extending its application from opaque to semitransparent devices, the PCE of dilute cell rises from 10.5% to 12.1%, with a high light utilization efficiency (LUE) of 3.5%. The findings provide practical solutions to the core device physical problem in OSCs.

14 SOLAR ENERGY↗
DOE OSTI2022

Self-Adhesive Ionomers for Alkaline Electrolysis: Optimized Hydrogen Evolution Electrode

Hydrogen produced through low-temperature water electrolysis using anion exchange membranes (AEM) combines the benefits of liquid-electrolyte alkaline electrolysis and solid-polymer proton exchange membrane electrolysis. The anion conductive ionomers in the oxygen-producing anode and hydrogen-producing cathode are a critical part of the three-dimensional electrodes. The ionomer in the hydrogen-producing cathode facilitates hydroxide ion conduction from the cathode catalyst to the anode catalyst, and water transport from the anode to the cathode catalyst through the AEM. This ionomer also binds the catalyst particles to the porous transport layer. Here in this study, the cathode durability was improved by use of a self-adhesive cathode ionomer to chemically bond the cathode catalyst particles to the porous transport layer. It was found that the cathode ionomers with high ion exchange capacity (IEC) were more effective than low IEC ionomers because of the need to transport water to the cathode catalyst and transport hydroxide away from the cathode. The cathode durability was improved by using ionomers which were soluble in the spray-coated cathode ink. Optimization of the catalyst and ionomer content within the cathode led to electrolysis cells which were both mechanically durable and operated at low voltage.

08 HYDROGEN↗
NASA NTRS1996

Atmospheric Pressure Method and Apparatus for Removal of Organic Matter with Atomic and Ionic Oxygen

A gas stream containing ionic and atomic oxygen in inert gas is used to remove organic matter from a substrate. The gas stream is formed by flowing a mixture of gaseous oxygen in an inert gas such as helium at atmospheric pressure past a high voltage, current limited, direct current arc which contacts the gas mixture and forms the ionic and atomic oxygen. The arc is curved at the cathode end and the ionic oxygen formed by the arc nearer to the anode end of the arc is accelerated in a direction towards the cathode by virtue of its charge. The relatively high mass to charge ratio of the ionic oxygen enables at least some of it to escape the arc before contacting the cathode and it is directed onto the substrate. This is useful for cleaning delicate substrates such as fine and historically important paintings and delicate equipment and the like.

Banks, Bruce A.↗
NASA NTRS1997

Atmospheric Pressure Method and Apparatus for Removal of Organic Matter with Atomic and Ionic Oxygen

A gas stream containing ionic and atomic oxygen in inert gas is used to remove organic matter from a substrate. The gas stream is formed by flowing a mixture of gaseous oxygen in an inert gas such as helium at atmospheric pressure past a high voltage, current limited, direct current arc which contacts the gas mixture and forms the ionic and atomic oxygen. The arc is curved at the cathode end and the ionic oxygen formed by the arc nearer to the anode end of the arc is accelerated in a direction towards the cathode by virtue of its charge. The relatively high mass to charge ratio of the ionic oxygen enables at least some of it to escape the arc before contacting the cathode and it is directed onto the substrate. This is useful for cleaning delicate substrates such as fine and historically important paintings and delicate equipment and the like.

Banks, Bruce A.↗
DOE OSTI2020

Zinc-iodine secondary energy storage methods, devices, and electrolytes

Disclosed are cathodes having electron-conductive high-surface-area materials, aqueous non-halide-containing electrolytes, secondary zinc-iodine energy storage devices using the same, and methods for assembling the same. The disclosed high-surface-area materials and the aqueous non-halide-containing electrolyte solutions can contribute together to the confinement of the active iodine species in the cathode and to the minimization of shuttle effects and self-discharging. The non-halide-containing electrolyte salts can facilitate preferential adsorption of the iodine species to the cathode material rather than dissolution in the aqueous electrolyte solution, thereby contributing to the confinement of the active iodine species.

25 ENERGY STORAGE↗
DOE OSTI2026

Linking DSC/TGA to Cell Levels: Energetics, Evolved Gases, and Thermal Safety of NMC811‐Graphite Micro‐Cell

Thermochemical characterization of battery materials links intrinsic material properties to decomposition pathways, heat generation, and gas evolution that govern performance and safety. Despite extensive work on NMC811-Graphite, variability across partial configurations and the limited adoption of micro-cell architectures (cathode+anode+electrolyte+separator) hinder robust cell-scale interpretation. Accordingly, this work establishes a bottom-up, component-resolved methodology integrating DSC/TGA, evolved gas analysis (EGA), and in situ XRD to link decomposition pathways and energy release across partial and micro-cell configurations, providing a transferable assessment of safety and stability in emerging chemistries. In separator-free configurations, the gas–solid reaction between cathode-evolved O 2 and anode-leached Li dominates the net heat release (1139 J g −1 ). In contrast, in the micro-cell configuration, the separator hinders O 2 transport and alters the timing and pathways of other reactions, and reduces the net energy release to 618 J g −1 . Energy release was organized into defined temperature windows that provide a framework for a thermodynamic model combining quantified gas evolution with selected decomposition pathways and effective reaction enthalpies to estimate net specific energy release, with agreement between DSC and cell-level tests. Ex situ XPS of heat-treated samples extends post-mortem analysis to thermal-abuse regimes, supporting key pathway elements.

25 ENERGY STORAGE↗
DOE OSTI2024

Cohesive phase-field chemo-mechanical simulations of inter- and trans- granular fractures in polycrystalline NMC cathodes via image-based 3D reconstruction

The optimal design and durable utilization of lithium-ion batteries necessitates an objective modeling approach to understand fracture and failure mechanisms. This paper presents a comprehensive chemo-mechanical modeling study focused on elucidating fracture-induced damage and degradation phenomena in the polycrystalline Li $\mathcal{x}$ Ni 0.5 Mn 0.3 Co 0.2 O 2 (NMC532) cathode. An innovative approach that utilizes image-based reconstructed 3D geometry as finite element (FE) mesh input is employed to enhance the precision in capturing the convoluted architecture and morphological features. For accurately representing the intricate crack configurations within the polycrystalline system, we adopted the cohesive phase-field fracture (CPF) model. Through the integration of advanced image-based geometry reconstruction technique and the promising CPF modeling approach, lithium (de)intercalation induced crack evolution (e.g., nucleation, propagation, branching and diverse modes including inter-/trans-(intra-) granular patterns) and the resulting chemical degradation can be precisely captured, which is also compared and validated with numerical predictions using a continuum damage model. In particular, this model predicts fracture induced degradation under varying fracture properties of grain boundaries and charging rates; the conclusion that NMC particles comprised of larger grains are predicted to have less degradation than those with smaller grains can also be drawn. This comprehensive analysis provides valuable insights into the fracture and degradation within polycrystalline NMC cathodes.

25 ENERGY STORAGE↗
DOE OSTI2022

Intercalation of Ca into a Highly Defective Manganese Oxide at Room Temperature

The utilization of oxide frameworks as intercalation cathodes for non-aqueous Ca-ion batteries potentially unlocks a new energy storage system that delivers high energy density. However, the slow kinetics of Ca 2+ in oxide electrodes strongly handicaps their activity and reversibility at room temperature. Here, nanocrystals of layered MnO x containing a high concentration of atomic defects and lattice water are shown to have remarkable electrochemical activity towards Ca 2+ , amounting to a capacity of ~130 mAh/g at room temperature. Multimodal characterization revealed the notable degree of intercalation by probing the structural, compositional and redox changes undertaken by the defective MnO x nanocrystals. The results suggest that the existence of atomic defects and lattice water played a role in improving Ca 2+ diffusivity in the oxide. These outcomes reaffirm the prospects for functional Ca-ion batteries using oxide cathodes under moderate conditions.

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

Chemical interaction and enhanced interfacial ion transport in a ceramic nanofiber–polymer composite electrolyte for all-solid-state lithium metal batteries

This article reports the synergy between ceramic nanofibers and a polymer, and the enhanced interfacial Li-ion transport along the nanofiber/polymer interface in a solid-state ceramic/polymer composite electrolyte, in which a three-dimensional (3D) electrospun aluminum-doped Li 0.33 La 0.557 TiO 3 (LLTO) nanofiber network is embedded in a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) matrix. Strong chemical interaction occurs between the nanofibers and the polymer matrix. Addition of the ceramic nanofibers into the polymer matrix results in the dehydrofluorination of the PVDF chains, deprotonation of the –CH 2 moiety and amorphization of the polymer matrix. Solid-state nuclear magnetic resonance (NMR) spectra reveal that lithium ions transport via three pathways: (i) intra-polymer transport, (ii) intra-nanofiber transport, and (iii) interfacial polymer/nanofiber transport. In addition, lithium phosphate is coated on the LLTO nanofiber surface before the nanofibers are embedded into the polymer matrix. The presence of lithium phosphate at the LLTO/polymer interface further enhances the chemical interaction between the nanofibers and the polymer, which promotes the lithium ion transport along the polymer/nanofiber interface. This in turn improves the ionic conductivity and electrochemical cycling stability of the nanofiber/polymer composite. As a result, the flexible LLTO/Li 3 PO 4 /polymer composite electrolyte membrane exhibits an ionic conductivity of 5.1 × 10 -4 S cm -1 at room temperature and an electrochemical stability window of 5.0 V vs. Li/Li + . A symmetric Li|electrolyte|Li half-cell shows a low overpotential of 50 mV at a constant current density of 0.5 mA cm -2 for more than 800 h. In addition, a full cell is constructed by sandwiching the composite electrolyte between a lithium metal anode and a LiFePO 4 -based cathode. Such an all-solid-state lithium metal battery exhibits excellent cycling performance and rate capability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗