The possibility of measuring the mobilities and concentration of charged particles in the atmosphere by the method of electrical shutters
Measurement of ion concentrations and mobilities in atmosphere by electrical shutter method
ION MOBILITY↗
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Results for “ion mobility”
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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Modeling electrokinetic flows with the discrete ion stochastic continuum overdamped solvent algorithm
In this article we develop an algorithm for the efficient simulation of electrolytes in the presence of physical boundaries. In previous work the discrete ion stochastic continuum overdamped solvent (DISCOS) algorithm was derived for triply periodic domains, and was validated through ion-ion pair correlation functions and Debye-Hückel-Onsager theory for conductivity, including the Wien effect for strong electric fields. In extending this approach to include an accurate treatment of physical boundaries we must address several important issues. First, the modifications to the spreading and interpolation operators necessary to incorporate interactions of the ions with the boundary are described. Next we discuss the modifications to the electrostatic solver to handle the influence of charges near either a fixed potential or dielectric boundary. An additional short-ranged potential is also introduced to represent interaction of the ions with a solid wall. Finally, the dry diffusion term is modified to account for the reduced mobility of ions near a boundary, which introduces an additional stochastic drift correction. Herein, several validation tests are presented confirming the correct equilibrium distribution of ions in a channel. Additionally, the methodology is demonstrated using electro-osmosis and induced-charge electro-osmosis, with comparison made to theory and other numerical methods. Notably, the DISCOS approach achieves greater accuracy than a continuum electrostatic simulation method. We also examine the effect of under-resolving hydrodynamic effects using a “dry diffusion” approach, and find that considerable computational speedup can be achieved with a negligible impact on accuracy.
97 MATHEMATICS AND COMPUTING↗
Ultrafast charging of energy-dense lithium-ion batteries for urban air mobility
Urban air mobility (UAM) demands batteries with high energy density, long cycle life, and fast rechargeability. In this paper, we demonstrate an energy-dense lithium-ion battery (LiB) with ultralong cycle life under ultrafast charging. By using the asymmetric temperature modulation (ATM) method, i.e., charging at an elevated temperature and discharging around the ambient temperature, it is experimentally shown that the 209 Wh/kg LiB is charged to 88% state of charge (SOC) in ~5 min under UAM cycling while retaining 97.7% capacity after 1,000 cycles. Moreover, an experimentally validated electrochemical-thermal (ECT) model is developed to elucidate the fast charging process and the degradation mode of UAM batteries, quantitatively capturing lithium plating during fast charging. We find that the LiBs for UAM applications are most prone to lithium plating due to their higher initial SOC required as the reserve for safety; nevertheless, the ATM method is effective in minimizing or preventing lithium plating in the high SOC range of 30-90%. In addition to slowing down capacity fade, the ATM method also raises the usable capacity by 10%, which boosts the battery energy density and ensures the battery to perform full UAM cycles even at the end of life.
25 ENERGY STORAGE↗
Protecting groups in insertion chemistry: Site-selective positioning of lithium ions in intercalation hosts
The expanding toolbox of functionalization chemistries for selectively installing moieties on specific sites of a substrate underpins almost all modern organic and biochemical syntheses. Likewise, the installation of mobile guest ions in specific interstitial sites and their transport along specific diffusion pathways forms the basis of modern lithium (Li)-ion battery electrodes. Many insertion hosts afford a diverse range of accessible interstitial sites. However, site-selective positioning of cations with atomic precision remains almost entirely unexplored. Here, we show that by deciphering site preferences of co/pre-intercalated cations, we can position Li ions in four distinct sites within a 1D ζ-V 2 O 5 insertion host. The use of topochemistry to effect single-crystal-to-single-crystal transformations enables atomic-resolution mapping of the selective positioning of Li ions through single-crystal X-ray diffraction. Here we image interstitial sites that are occupied at high depths of discharge, thereby obtaining unprecedented structural insight into “fully stuffed” frameworks critical for the realization of high-energy-density intercalation electrodes.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Semiclassical theory of proton transport in ice.
Proton mobility in ice when limited by lattice scattering calculated, using Boltzmann transport equation
ION MOBILITY↗
Role of Intra-Domain Heterogeneity on Ion and Polymer Dynamics in Block Polymer Electrolytes: An Approach for Spatially Resolving Dynamics and Ion Transport
The design of safe and high-performance, nanostructured, block polymer (BP) electrolytes for lithium-ion batteries requires a thorough understanding of the key parameters that govern local structure and dynamics. Yet, the interfaces between microphase separated domains can introduce complexities in this local behavior that can be challenging to quantify. Herein, the local polymer, cation (Li + ), and anion dynamics were described in salt-doped polystyrene block poly(oligo-oxyethylene methyl ether methacrylate) (PS-b-POEM) through a quantitative framework that considered the effects of polymer architecture, segmental mixing, chain stretching, and confinement on polymer mobility and ion transport. This framework was validated through nuclear magnetic resonance (NMR) spectroscopy measurements on solid (dry) polymer electrolyte samples. Notably, a mobility transition temperature (T mobility ) was identified through NMR spectroscopy that captured the local dynamics more accurately than the thermal glass transition temperature. Additionally, the approach quantitatively described the mobility gradient across a domain when segmental mixing effects were combined with chain stretching and confinement information, especially at higher segregation strengths – facilitating the assessment of local ion diffusion and conductivity. As a result, spatially averaged local ion diffusion predictions quantitatively matched NMR-measured ion diffusivities in the BP samples, while spatially summed ionic conductivity predictions across a domain qualitatively captured trends in the measured ionic conductivities.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
D-Region Mobility Spectrometer
D-region mobility and constituents abundance spectrometer device based on continuum concepts
MASS SPECTROMETER↗
Full Device Evaluation of Metal Halide Perovskite Solar Cells in Low Earth Orbit Aboard the International Space Station
This study investigates how sustained low Earth orbit (LEO) exposure affects metal halide perovskite (MHP) thin films and perovskite solar cells (PSCs). It examines samples deployed on the Materials International Space Station Experiment (MISSE) 15 and 16 missions. Five methylammonium lead iodide (MAPI) thin films are deployed on MISSE-16, each with distinct UV filters to selectively attenuate AM0 spectral bands. While post-flight optical analysis reveals that the least UV-exposed film exhibits the highest emission and lowest non-radiative recombination rate, no clear correlation is observed among the rest, and all MAPI films maintained excellent integrity throughout the mission. MISSE-15 deployed eight PSCs with diverse structures, MHP compositions, and contact materials. Post-flight analysis reveals stable, highly emissive MHPs, but damaged contacts due to ion migration, which caused loss of electrical response. The MISSE missions demonstrate MHPs' suitability for space applications, while highlighting the need for improved interfacial layers and contact materials to enhance charge carrier mobility, prevent ion migration, and improve charge carrier extraction efficiency.
14 SOLAR ENERGY↗
Miniature electrospray ionization/ion mobility spectrometer (ESI/IMS) system for detection of organic molecules on Mars
Explore the source record for details and available documents.
electrospray ionization ion mobility astrobiology↗
Fast Li-Ion Conductivity in Superadamantanoid Lithium Thioborate Halides
Lithium thioborates are promising fast Li-ion conducting materials, with similar properties to their lithium thiophosphate counterparts that have enabled the development of solid-state Li-ion batteries. By comparison, thioborates have scarcely been developed, however, offering new space for materials discovery. In this work, we report a new class of lithium thioborate halides that adopt a so-called supertetrahedral adamantanoid structure that houses mobile lithium ions and halide anions within interconnected 3D structural channels. Investigation of the structure using single-crystal XRD, neutron powder diffraction, and neutron PDF reveals significant lithium and halide anion disorder. The phases are non-stoichiometric, adopting slightly varying halide contents within the materials. These new superadamantanoid materials exhibit high ionic conductivities up to 1.4 mS cm -1 , which can be effectively tuned by the polarizability of the halide anion within the channels.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Electrical structure and E-fields in the high-latitude mesosphere
A description of the electric structure as observed during a rocket sounding noctilucent cloud (NLC) observation program in the summer of 1991, is presented. Both NLC and polar mesosphere summer echo (PMSE) conditions were determined. The observable effects on ions and electrons were measured in the NLC and PMSE regions and associated electric field (E-fields) measurements indicated small alternating current vertical fields. The following findings are reported: small and large scale electron density structure is noticeable in the NLC regions; above 82 km, the occurrence of very low-mobility positive ions directly demonstrates the existence of charged aerosols, and small alternating current vertical electric fields were observed in the NLC and PMSE region.
Mitchell, John D.↗
Ion separations with membranes
Ion separations are important for resource recovery, water treatment, and energy production and storage. Techniques such as chemical precipitation, selective adsorption, and solvent extraction are effective, but membranes may separate ions continuously with less waste and lower energy costs. Separation of monovalent and multivalent ions with nanofiltration or electrodialysis membranes already enables water softening and edible salt purification. Similar membranes are attractive as separators in vanadium redox flow batteries. Selective partitioning of divalent counter-ions into ion-exchange membranes even allows transport of these ions against their concentration gradients in salt mixtures. However, separations of ions with the same charge is more challenging. Recent research demonstrated highly selective ion “sieving” at small scales. Here, separations using electrical potentials and differences in ion electrophoretic mobilities are promising, but relatively unexplored. Carrier-mediated transport affords high selectivity in liquid membranes, but these systems are not very stable, and selective transport via hopping between anchored carriers has proven elusive. Finally, this paper discusses how concentration polarization decreases selectivities in many membrane processes. Although development of selective, inexpensive ion-separation membranes is a work in progress, successes in water softening and edible salt purification suggests that future selective membranes will serve as complementary methods to traditional purification techniques.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Mechanisms of Protonic Nonvolatile Memory Device
A nonvolatile memory device based on protonic transport in oxides has been proposed. The mobile H+ ions are introduced into the SiO2 layer by annealing Si/SiO2/Si structures in H2 at temperatures greater than 500 deg C. This effect has only been observed for confined oxides that have been annealed at greater than or equal to 1100 C prior to the hydrogenation anneal. This includes buried oxides such as Unibond and SIMOX as well as thermal oxides annealed with a polysilicon cap. An applied field moves the charge within the oxide and the charge stops moving when the field is removed. In a memory device, the hydrogen-annealed oxide is the gate oxide and the position of the mobile charge is sensed by the shift of the I-V curve. Much is still not understood about the motion of the charge across the buried oxide. Previous work has assumed that H+ transport and the time it takes to traverse the oxide is governed by interactions within the bulk of the oxide. Based on parameters that affect the transport time, we conclude that H+ trapping and detrapping at the Si/SiO2 interface are more important than H+ interactions within the oxide bulk. These parameters include the applied field, the H+ concentration and the oxide thickness. One consequence is that projections of device write-time based on the previous assumptions of H+ transport mechanisms may be overly optimistic.
P J Macfarlane↗
Effects Of Electric Field On Hydrocarbon-Fueled Flames
It has been observed that flames are susceptible to electric fields that are much weaker than the breakdown field strength of the flame gases. When an external electric field is imposed on a flame, the ions generated in the flame reaction zone drift in the direction of the electric forces exerted on them. The moving ions collide with the neutral species and change the velocity distribution in the affected region. This is often referred to as ionic wind effect. In addition, the removal of ions from the flame reaction zone can alter the chemical reaction pathway of the flame. On the other hand, the presence of space charges carried by moving ions affects the electric field distribution. As a result, the flame often changes its shape, location and color once an external electric field is applied. The interplay between the flame movement and the change of electric field makes it difficult to determine the flame location for a given configuration of electrodes and fuel source. In normal gravity, the buoyancy-induced flow often complicates the problem and hinders detailed study of the interaction between the flame and the electric field. In this work, the microgravity environment established at the 2.2 Second Drop Tower at the NASA Glenn Research Center is utilized to effectively remove the buoyant acceleration. The interaction between the flame and the electric field is studied in a one-dimensional domain. A specially designed electrode makes flame current measurements possible; thus, the mobility of ions, ion density, and ionic wind effect can be evaluated.
Yuan, Z.-G.↗
Poly(norbornene) anion conductive membranes: homopolymer, block copolymer and random copolymer properties and performance
It has previously been shown that phase-separated block copolymers with non-ion conducting (hydrophobic) blocks and ion conducting (hydrophilic) blocks can form efficient ion conducting channels with high ionic mobility and conductivity. Block copolymers can provide a means for phase segregation and ion channel formation while homopolymers and random copolymers have been shown to have lower ion mobility. In this study, the properties of poly(norbornene) based anion exchange membranes (AEMs) comprising homopolymers, block copolymers, and random copolymers with high ion-exchange capacity (IEC) (3.48–4.55 meq. g -1 ) have been investigated and compared. The polymers were cross-linked with N,N,N',N'-tetramethyl-1,6-hexanediamine before casting the membranes to avoid excessive water swelling due to high water uptake. It was shown that high ionic conductivity can be achieved in both random copolymers and homopolymers even in the absence of microphase-separated structures. For example, the conductivity of a random copolymer was 194 mS cm -1 at 80 °C, which was comparable to the block copolymer, 201 mS cm -1 at 80 °C. The H 2 /O 2 fuel cell performance of random copolymer composite membranes showed a peak power density of 3.05 W cm -2 and peak current density of 7.85 A cm -2 at 80 °C compared to block copolymer membranes (peak power density of 3.21 W cm -2 and peak current density of 8.27 A cm -2 at 80 °C). It is more critical that high water transport be achieved in AEMs than achieving a phase-segregated morphology. Finally, the homopolymer, block copolymer, and random copolymer membranes showed <1.35% degradation after aging in 1 M NaOH at 80 °C for 1000 h.
08 HYDROGEN↗
Effect of modulator sorption on gradient shape in ion-exchange chromatography
Mobile phase additives, or modulators, are used in gradient elution chromatography to facilitate separation and reduce separation time. The modulators are usually assumed to be linearly adsorbed or unadsorbed. Here, the consequences of nonlinear modulator adsorption are examined for ion-exchange gradient elution through a series of simulations. Even when the buffer salt is identical to the modulator salt, gradient deformation is observed; the extent of deformation increases as the volume of the feed is increased. When the modulator salt is different from the buffer salt, unusual effects are observed, and the chromatograms are quite different from those predicted by classical gradient elution theory. In particular, local increases in the buffer concentration are found between feed bands, and serve to improve the separation. These effects become more pronounced as the feed volume increases, and could therefore prove valuable in preparative applications.
NASA Discipline Life Support Systems↗
Improving Ionic Conformality Across Polymer Electrolyte|Electrode Interfaces
Maintaining uniform ionic transport at electrode|electrolyte interfaces, i.e., ionic conformality, remains challenging in polymer electrolyte (PE)-based solid-state batteries. Morphological conformality does not necessarily imply ionic conformality. In PEs, which typically consist of a mechanically supporting component and distinct ionically conductive components, the rearrangement or depletion of mobile ion-conductive domains at interfaces can disrupt ionic transport pathways. Such localized ionic depletion contributes to interfacial instability and capacity degradation in high-voltage lithium-metal batteries. Herein, an electrolyte design approach aimed at minimizing interfacial heterogeneities is demonstrated through compositional adjustments, characterized by spatially resolved structural and chemical X-ray techniques and NMR diffusometry to elucidate ion transport dynamics. This approach improves ionic conformality at electrode interfaces, enhancing cycling stability in Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NMC811) coin and pouch cells cycled at high voltages. These results contribute to understanding interfacial behaviors in multiphase PEs and inform strategies for improving stability across solid-state battery interfaces.
36 MATERIALS SCIENCE↗
Field‐Relevant Degradation Mechanisms in Metal Halide Perovskite Modules
Field testing, failure analysis, and understanding of degradation mechanisms are essential to advancing metal halide perovskite (MHP) photovoltaic (PV) technology toward commercialization. Here, we present performance data from up to 1 year of outdoor testing of MHP modules in Golden, Colorado. The module encapsulation architecture and encapsulant materials have a significant impact on module reliability, with modules containing a polyolefin elastomer (POE) in addition to a desiccated polyisobutylene (PIB) edge seal outlasting modules with only a PIB edge seal or PIB blanket. Nondestructive and destructive characterization of the field-tested modules points to module scribes and interfaces as areas of potential mechanical weakness and chemical migration, resulting in shunt pathways and increased series resistance. Finally, indoor accelerated stress testing with light and elevated temperatures is performed, demonstrating failure with similar scribe degradation signatures as compared to the field-tested modules. In conclusion, under both outdoor testing and light and elevated temperature conditions, electrochemical corrosion between the copper electrode and the mobile iodine ions appeared dominant, with a significant progression at the scribes that is speculated to result from an interplay between the initial laser damage and joule heating from enhanced ion diffusion under bias.
14 SOLAR ENERGY↗