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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Parametric study of ion heating in a burnout device (HIP-1)

Results of further studies on the Lewis Research Center hot-ion plasma source (HIP-1) are reported. Changes have been made in both the electrode geometry and materials to produce higher ion temperatures. Ion temperature increased significantly with increased vacuum pumping speed. The best ion temperatures achieved, so far, for H(+), D(+), and He(+) plasmas are estimated to be equal to, or greater than 0.6, equal to, or greater than 0.9, and equal to, greater than 2.0 keV, respectively. Electrode pairs produced high ion temperatures whether on the magnetic axis or off it by 5.5 cm. Multiple sources, one on-axis and one off-axis, were run simultaneously from a single power supply by using independent gas feed rates. A momentum analyzer has been added to the charge-exchange neutral particle analyzer to identify particles according to mass, as well as energy. Under any given plasma condition, the higher mass ions have higher average energies but not by as much as the ratio of their respective masses.

Sigman, D. R.↗
NASA NTRS1988

Electrochemical processing of solid waste

The investigation into electrolysis as a means of waste treatment and recycling on manned space missions is described. The electrochemical reactions of an artificial fecal waste mixture was examined. Waste electrolysis experiments were performed in a single compartment reactor, on platinum electrodes, to determine conditions likely to maximize the efficiency of oxidation of fecal waste material to CO2. The maximum current efficiencies for artificial fecal waste electrolysis to CO2 was found to be around 50 percent in the test apparatus. Experiments involving fecal waste oxidation on platinum indicates that electrodes with a higher overvoltage for oxygen evolution such as lead dioxide will give a larger effective potential range for organic oxidation reactions. An electrochemical packed column reactor was constructed with lead dioxide as electrode material. Preliminary experiments were performed using a packed-bed reactor and continuous flow techniques showing this system may be effective in complete oxidation of fecal material. The addition of redox mediator Ce(3+)/Ce(4+) enhances the oxidation process of biomass components. Scientific literature relevant to biomass and fecal waste electrolysis were reviewed.

Bockris, J. OM.↗
NASA NTRS1973

Research into the feasibility of metal- and oxide-film capacitors

Thin film capacitors with up to twenty-two active layers have been deposited by RF sputtering. The materials were aluminum electrodes of 1200 to 1500 angstrom thickness and silica dielectric layers of 3000 to 6000 angstrom thickness. The best electrical characteristics were capacitances of nearly 0.1 microfarad for an active area of 1.25 square centimeters, dissipation factor of less than 0.01 over a frequency range of 0.5 to 100 kilohertz and energy density of approximately 70 millijoules per cubic centimeter of active deposited material at a working voltage of 40 volts. These aluminum-silica capacitors exhibit excellent electrical stability over a temperature range from -55 C to +300 C.

Jorgenson, G. V.↗
DOE OSTI2020

First-Principles Modeling of Sodium Ion and Water Intercalation into Titanium Disulfide Interlayers for Water Desalination

Recent experiments revealed the possibility of using titanium disulfide (TiS 2 ) as the cathode material in capacitive deionization (CDI) devices for water desalination. Although it performed stably up to 70 cycles with a salt removal capacity of 14 mg/g (corresponding to a sodium ion removal capacity of 35.8 mg/g) at high molar concentration (600 mM NaCl), the maximum capacity of TiS 2 as a CDI electrode was much lower (~70 mAh/g) than as a supercapacitor (239 mAh/g). Understanding why the ion capacities of these two configurations of the same material differ will entail elucidating detailed charge/discharge mechanisms at the atomic scale. Here, we present density functional theory simulations of sodium intercalation into TiS 2 interlayers in order to gain such understanding. We systematically investigated TiS 2 stacking patterns and ion intercalation sites, energetics of the intercalated compounds, and phase transformation during sodium intercalation. The calculated structural evolution and capacitance–voltage curve agree quite well with previous measurements. We conclude that the different maximum capacities of TiS 2 measured in aqueous and dry environments originate from weaker interlayer interactions with respect to shear strain after ~33% intercalation of Na + –H 2 O pairs, which is detrimental to the mechanical stability of TiS 2 . In conclusion, this study sheds light on the underlying mechanisms of ion intercalation into layered materials and contributes to understanding requirements for future design and optimization of CDI electrode materials for water desalination.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Electrochemical cells for direct oxide reduction, and related methods

A method of direct oxide reduction includes forming a molten salt electrolyte in an electrochemical cell, disposing at least one metal oxide in the electrochemical cell, disposing a counter electrode comprising a material selected from the group consisting of osmium, ruthenium, rhodium, iridium, palladium, platinum, silver, gold, lithium iridate, lithium ruthenate, a lithium rhodate, a lithium tin oxygen compound, a lithium manganese compound, strontium ruthenium ternary compounds, calcium iridate, strontium iridate, calcium platinate, strontium platinate, magnesium ruthenate, magnesium iridate, sodium ruthenate, sodium iridate, potassium iridate, and potassium ruthenate in the electrochemical cell, and applying a current between the counter electrode and the at least one metal oxide to reduce the at least one metal oxide. Related methods of direct oxide reduction and related electrochemical cells are also disclosed.

Tripathy, Prabhat K.↗
DOE OSTI2024

Elucidating the complex interplay between thermodynamics, kinetics, and electrochemistry in battery electrodes through phase-field modeling

Abstract This article highlights applications of phase-field modeling to electrochemical systems, with a focus on battery electrodes. We first provide an overview on the physical processes involved in electrochemical systems and applications of the phase-field approach to understand the thermodynamic and kinetic mechanisms underlying these processes. We employ two examples to highlight how realistic thermodynamics and kinetics can naturally be incorporated into phase-field modeling of electrochemical processes. One is a composite battery cathode with an intercalation compound (Li x FePO 4 ) as the electrochemically active material, and the other is a displacement reaction compound (Li–Cu–TiS 2 ). With the input parameters mostly from atomistic calculations and experimental measurements, phase-field simulations allowed us to untangle the interactions among transport, reaction, electricity, chemistry, and thermodynamics that lead to highly complex evolution of the materials within battery electrodes. The implications of these observations for battery performance and degradation are discussed. Graphical abstract

Andrews, W. Beck (ORCID:0000000287824621)↗
NASA NTRS1993

Plasma-puff initiation of high Coulomb transfer switches

The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. The optimal fill gas pressures for the azimuthally uniform plasma-puff were about 120 mTorr less than P(opt) less than 450 Torr for He and N2. For Argon 120 mTorr less than P(opt) less than 5 Torr for argon. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with hypocycloidal pinch plasma-puff triggering. The main discharge of the inverse pinch switch with the plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with the hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. In order to assess the effects of plasma current density on material erosion of electrodes, emissions from both an inverse-pinch plasma switch (INPIStron) and from a spark gap switch under test were studied with an optical multichannel analyzer (OMA). The color temperature of the argon plasma was approximately 4,000 K which corresponded with the peak continuum emission near 750 nm. There are the strong line emissions of argon in the 650 - 800 nm range and a lack of line emissions of copper and other solid material used in the switch. This indicates that the plasma current density during closing is low and the hot spot or hot filament in the switch is negligible. This result also indicates considerable reduction of line emission with the INPIStron switch over that of a spark-gap switch. However, a strong carbon line emission exists due to vaporization of the plastic insulator used. In order to reduce the vaporization of the insulator, the plexiglass insulating material of INPIStron was replaced with Z-9 material. A comparative study of the INPIStron and a spark gap also reveals that the INPIStron, with a low impedance of Z equals 9 ohms, can transfer a high voltage pulse with a superior pulse-shape fidelity over that of a spark gap with Z equals 100 ohms.

Venable, D. D.↗
NASA NTRS1993

Plasma-puff initiation of high Coulomb transfer switches

The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. The optimal fill gas pressures for the azimuthally uniform plasma-puff were about 120 mTorr less than P(sub opt) less than 450 Torr for He and N2. For Argon 20 mTorr is less than P(sub opt) is less than 5 Torr. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with hypocycloidal pinch plasma-puff triggering. The main discharge of the inverse pinch switch with the plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with the hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. In order to assess the effects of plasma current density on material erosion of electrodes, emissions from both an inverse-pinch plasma switch (INPIStron) and from a spark gap switch under test were studied with an optical multichannel analyzer (OMA). The color temperature of the argon plasma was approximately 4,000 K which corresponded with the peak continuum emission near 750 nm. There are the strong line emissions of argon in the 650 - 800 nm range and a lack of line emissions of copper and other solid material used in the switch. This indicates that the plasma current density during closing is low and the hot spot or hot filament in the switch is negligible. This result also indicates considerable reduction of line emission with the INPIStron switch over that of a spark-gap switch. However, a strong carbon line emission exists due to vaporization of the plastic insulator used. In order to reduce the vaporization of the insulator, the plexiglass insulating material of INPIStron was replaced with Z-9 material. A comparative study of the INPIStron and a spark gap also reveals that the INPIStron, with a low impedance of Z = 9 ohms, can transfer a high voltage pulse with a superior pulse-shape fidelity over that of a spark gap with Z = 100 ohms.

Han, Kwang S.↗
DOE OSTI2022

Production of fast-charge Zn-based aqueous batteries via interfacial adsorption of ion-oligomer complexes

Abstract Aqueous zinc batteries are attracting interest because of their potential for cost-effective and safe electricity storage. However, metallic zinc exhibits only moderate reversibility in aqueous electrolytes. To circumvent this issue, we study aqueous Zn batteries able to form nanometric interphases at the Zn metal/liquid electrolyte interface, composed of an ion-oligomer complex. In Zn||Zn symmetric cell studies, we report highly reversible cycling at high current densities and capacities (e.g., 160 mA cm −2 ; 2.6 mAh cm −2 ). By means of quartz-crystal microbalance, nuclear magnetic resonance, and voltammetry measurements we show that the interphase film exists in a dynamic equilibrium with oligomers dissolved in the electrolyte. The interphase strategy is applied to aqueous Zn||I 2 and Zn||MnO 2 cells that are charged/discharged for 12,000 cycles and 1000 cycles, respectively, at a current density of 160 mA cm −2 and capacity of approximately 0.85 mAh cm −2 . Finally, we demonstrate that Zn||I 2 -carbon pouch cells (9 cm 2 area) cycle stably and deliver a specific energy of 151 Wh/kg (based on the total mass of active materials in the electrode) at a charge current density of 56 mA cm −2 .

25 ENERGY STORAGE↗
DOE OSTI2020

Comparative Analysis of Capacitive Sensors with Different Geometrical layouts for Cable Insulation Degradation Detection

This paper presents a comparative analysis between an Interdigital Capacitor (IDC) sensor and a Serpentine Capacitive (SRC) sensor. The effects of electrode layouts on sensor performance are studied by means of finite element simulation where the geometrical dimensions (except electrode length) and material characteristics of both sensors are identical. Conformal IDC and SRC sensors with equal sensor area are modeled on a cable surface. The simulation results show a tradeoff between IDC and SRC sensors in terms of sensitivity and penetration depth. The SRC sensor shows 13.3% increase in sensitivity and 16.8% increase in capacitance compared to the IDC sensor, though the electric field penetration depth of the SRC sensor is 18.8% lower than the IDC sensor. In addition, the effects of change in electrode width, inter-electrode gap, and number of electrodes on SRC and IDC sensor comparative performance are evaluated.

Interdigital Capacitance, Serpentive Capacitive Se↗
NASA NTRS1990

Lunar oxygen and metal for use in near-earth space - Magma electrolysis

The unique conditions on the moon, such as vacuum, absence of many reagents common on the earth, and presence of very nontraditional 'ores', suggest that a unique and nontraditional process for extracting materials from the ores may prove the most practical. An investigation has begun into unfluxed silicate electrolysis as a method for extracting oxygen, Fe, and Si from lunar regolith. The advantages of the process include simplicity of concept, absence of need to supply reagents from the earth, and low power and mass requirements for the processing plant. Disadvantages include the need for uninterrupted high temperature and the highly corrosive nature of the high-temperature silicate melts, which has made identifying suitable electrode and container materials difficult.

Colson, Russell O.↗
DOE OSTI2024

Optimizing protic ionic liquid electrolyte for pre-intercalated Ti 3 C 2 T x MXene supercapacitor electrodes

Electrical double-layer capacitors (EDLCs) are of increasing importance in energy storage from renewable sources. The properties of the electrode and electrolyte materials influence the energy and power densities of EDLCs. We examined the specific capacitance and ion dynamics of a protic ionic liquid confined in pre-intercalated Ti 3 C 2 T x MXene. Our electrochemical measurements demonstrated that the creation of a protic ionic liquid, 1-butyl-3-H-imidazolium bis(trifluoromethanesulfonyl)imide (BuIMH-NTf2), using a mixture of ionic liquid, 1-butyl imidazole (BuIM), and salt, bis(trifluoromethanesulfonyl)imide (HNTf2), in a ratio of 0.8:0.2 led to the optimal capacitance. Remarkably, quasi-elastic neutron scattering measurements revealed increased particle mobility at this composition, attributed to the more efficient accumulation of BuIMH + on the electrode surface. This deposit of additional ions results in fewer BuIM molecules away from the surface, enhancing their mobility due to reduced crowding. This composition-dependent electrochemical behavior will guide the formulation of more efficient protic ionic liquid systems, enabling faster ion transport in energy storage devices.

36 MATERIALS SCIENCE↗
DOE OSTI2026

The Influence of Mesoscale Particle Structure on the Electrode Degradation and Resultant Electrochemistry of Lithium Ion Cells With Nickel Rich Lithium Nickel Manganese Cobalt Oxide Positive Electrodes

Nickel-rich lithium nickel manganese cobalt oxide, NMC (LiNi x Mn y Co z O 2 ), materials are desirable positive electrodes in lithium ion batteries, providing high capacity and energy density. The mesoscale structure of NMC materials is commonly a polycrystalline aggregate, providing opportunity for short lithium ion transport distance of the small primary particles, yet facile material handling due to the larger secondary particles. On (de)lithiation the NMC unit cell changes volume, where the anisotropic strain can result in secondary particle fracture. This secondary particle fracture process during cycling has been associated with several degradation modes of NMC materials in LIBs. In this work, a milling process was determined whereby the secondary particles could be pre-fractured with retention of the parent primary particle crystallographic structure, crystallite size, and morphology, providing the ability to unambiguously determine the influence of NMC secondary particle size and mesostructure on resultant functional behavior. The bulk and interfacial properties and electrochemistry of as-received commercially obtained polycrystal NMC811 (LiNi 0.8 Mn 0.1 Co 0.1 O 2 , PC NMC) and its milled MPC NMC counterpart were compared. The smaller secondary particle size, higher surface area MPC NMC was found to result in 1) greater cathode tortuosity, 2) reduced surface Ni on the cycled MPC cathodes consistent with surface reconstruction, and 3) increased Ni deposition on the anodes from cathode-anode crosstalk. These factors manifested in unfavorable electrochemical behavior of MPC with lower functional capacity at both 1C and C/10 rates and higher impedance over extended moderate voltage (dis)charge cycling.

36 MATERIALS SCIENCE↗
NASA NTRS1990

Lunar oxygen and metal for use in near-Earth space: Magma electrolysis

Because it is energetically easier to get material from the Moon to Earth orbit than from the Earth itself, the Moon is a potentially valuable source of materials for use in space. The unique conditions on the Moon, such as vacuum, absence of many reagents common on the Earth, and the presence of very nontraditional ores suggest that a unique and nontraditional process for extracting materials from the ores may prove the most practical. With this in mind, an investigation of unfluxed silicate electrolysis as a method for extracting oxygen, iron, and silicon from lunar regolith was initiated and is discussed. The advantages of the process include simplicity of concept, absence of need to supply reagents from Earth, and low power and mass requirements for the processing plant. Disadvantages include the need for uninterrupted high temperature and the highly corrosive nature of the high-temperature silicate melts which has made identifying suitable electrode and container materials difficult.

Colson, Russell O.↗
NASA NTRS1990

Studies on the properties and performance of TiS2 cathodes

Influence of raw material source, processing methods, and cell operating voltage limits on the performance of TiS2 cathode was examined. Raw materials obtained from three different sources were investigated. TiS2 electrodes were fabricated by painting, rolling, and pressing methods. Raw materials and electrodes were characterized for their physical, chemical, and electrochemical properties. The results obtained indicated that the performance of TiS2 cathodes was dependent on the purity and stoichiometry of the TiS2 material. Fabrication methods were found to have minimal influence on the performance of cathodes. The capacity loss observed during the early stages of cycling was attributed to the trapping of lithium in TiS2. Operating voltage limits were found to have significant influence on the cycle life performance of the cells.

Huang, C.-K.↗
DOE OSTI2022

Transparent conducting oxides: from all-dielectric plasmonics to a new paradigm in integrated photonics

During the past few years, the optics and photonics communities have renewed their attention toward transparent conducting oxides (TCOs), which for over two decades have been broadly employed for the fabrication of transparent electrodes in photovoltaic and communication technologies. This reinvigorated research curiosity is twofold: on the one hand, TCOs, with their metal-like properties, low optical absorption, and fabrication flexibility, represent an appealing alternative to noble metals for designing ultra-compact plasmonic devices. On the other hand, this class of hybrid compounds has been proved to possess exceptionally high optical nonlinearities when operating on a frequency window centered around their crossover point, the wavelength point at which the real part of the dielectric permittivity switches sign. Because TCOs are wide-bandgap materials with the Fermi level located in the conduction band, they are hybrid in nature, thus presenting both interband and intraband nonlinearities. This is the cause of a very rich nonlinear physics that is yet to be fully understood and explored. In addition to this, TCOs are epsilon-near-zero (ENZ) materials within a broad near-infrared spectral range, including the entire telecom bandwidth. In this operational window a myriad of novel electromagnetic phenomena have been demonstrated experimentally such as supercoupling, wavefront freezing, and photon doping. Furthermore, TCOs stand out among all other ENZ systems due to one fundamental characteristic, which is hardly attainable even by using structured materials. In fact, around their ENZ wavelength and for a quite generous operational range, these materials can be engineered to have an extremely small real index. This peculiarity leads to a slow-light effect that is ultimately responsible for a significant enhancement of the material nonlinear properties and is the cornerstone of the emerging field of near-zero-index photonics. In this regard, the recent history of nonlinear optics in conductive oxides is growing extremely fast due to a great number of experiments reporting unprecedentedly remarkable effects, including unitary index change, bandwidth-large frequency shift, efficient ultra-low-power frequency conversion, and many others. This review is meant to guide the reader through the exciting journey of TCOs, starting as an industrial material for transparent electrodes, then becoming a new alternative for low-loss plasmonics, and recently opening up new frontiers in integrated nonlinear optics. The present review is mainly focused on experimental observations.

42 ENGINEERING↗
DOE OSTI2023

Integrated Multiscale Model for Design of Robust 3D Solid-state Lithium Batteries

In FY23, we successfully established the multiscale modeling framework for probing the effects of materials microstructure on cell performance of 3D solid-state batteries. The framework covers physicochemical processes co-evolving at the atomistic and microstructure scales. Our simulations revealed the mechanism of initial interfacial degradation, formation of secondary phases, and the structure-property relationship for ion transport and mechanical stability at the interface. In addition, we also established the microstructure-performance relationships by performing sensitivity tests of various microstructure features and extracting their impact on cell performance during charge-discharge cycles. We have successfully applied our multiscale, multiphysics modeling capability to common electrode and electrolyte materials that are of interests to VTO and the experimental teams within the US-Germany collaboration. The insights we obtained from these simulations provide valuable design principles to optimize materials properties for advanced 3D solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2023

Continuum kinetic investigation of the impact of bias potentials in the current saturation regime on sheath formation

In this work, we examine sheath formation in the presence of bias potentials in the current saturation regime for pulsed power fusion experiments. It is important to understand how the particle and heat fluxes at the wall may impact the wall material and affect electrode degradation. Here, simulations are performed using the 1X-1V Boltzmann–Poisson system for a proton–electron plasma in the presence of bias potentials ranging from 0 to 10 kV. The results indicate that the sheath near the anode remains generally the same as that of a classical sheath without the presence of a bias potential. However, the sheath near the cathode becomes more prominent with a larger potential drop, a significant decrease in the electron density, and larger sheath lengths. The spatially constant current density increases to a saturation value with the increasing bias potential. For high bias potentials, the material choice needs to consider that the anode faces significantly larger particle and heat fluxes compared to the cathode. In general, the results trend with theory with differences attributed to the simplified assumptions in the theory and the kinetic effects considered in the simulations. Due to the significant computational cost of a well resolved 1X-2V simulation, only one such simulation is performed for the 5 kV case showing higher current.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗