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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Cas9-derived peptides presented by MHC Class II that elicit proliferation of CD4 + T-cells

CRISPR–Cas9 mediated genome editing offers unprecedented opportunities for treating human diseases. There are several reports that demonstrate pre-existing immune responses to Cas9 which may have implications for clinical development of CRISPR-Cas9 mediated gene therapy. Here we use 209 overlapping peptides that span the entire sequence of Staphylococcus aureus Cas9 (SaCas9) and human peripheral blood mononuclear cells (PBMCs) from a cohort of donors with a distribution of Major Histocompatibility Complex (MHC) alleles comparable to that in the North American (NA) population to identify the immunodominant regions of the SaCas9 protein. We also use an MHC Associated Peptide Proteomics (MAPPs) assay to identify SaCas9 peptides presented by MHC Class II (MHC-II) proteins on dendritic cells. Using these two data sets we identify 22 SaCas9 peptides that are both presented by MHC-II proteins and stimulate CD4 + T-cells.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

In vivo volumetric imaging of calcium and glutamate activity at synapses with high spatiotemporal resolution

Studying neuronal activity at synapses requires high spatiotemporal resolution. For high spatial resolution in vivo imaging at depth, adaptive optics (AO) is required to correct sample-induced aberrations. To improve temporal resolution, Bessel focus has been combined with two-photon fluorescence microscopy (2PFM) for fast volumetric imaging at subcellular lateral resolution. To achieve both high-spatial and high-temporal resolution at depth, we develop an efficient AO method that corrects the distorted wavefront of Bessel focus at the objective focal plane and recovers diffraction-limited imaging performance. Applying AO Bessel focus scanning 2PFM to volumetric imaging of zebrafish larval and mouse brains down to 500 µm depth, we demonstrate substantial improvements in the sensitivity and resolution of structural and functional measurements of synapses in vivo. This enables volumetric measurements of synaptic calcium and glutamate activity at high accuracy, including the simultaneous recording of glutamate activity of apical and basal dendritic spines in the mouse cortex.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Structure of the Sec14 domain of Kalirin reveals a distinct class of lipid-binding module in RhoGEFs

Gated entry of lipophilic ligands into the enclosed hydrophobic pocket in stand-alone Sec14 domain proteins often links lipid metabolism to membrane trafficking. Similar domains occur in multidomain mammalian proteins that activate small GTPases and regulate actin dynamics. The neuronal RhoGEF Kalirin, a central regulator of cytoskeletal dynamics, contains a Sec14 domain (Kal bSec14 ) followed by multiple spectrin-like repeats and catalytic domains. Previous studies demonstrated that Kalirin lacking its Sec14 domain fails to maintain cell morphology or dendritic spine length, yet whether and how Kal bSec14 interacts with lipids remain unknown. Here, we report the structural and biochemical characterization of Kal bSec14 . Kal bSec14 adopts a closed conformation, sealing off the canonical ligand entry site, and instead employs a surface groove to bind a limited set of lysophospholipids. The low-affinity interactions of Kal bSec14 with lysolipids are expected to serve as a general model for the regulation of Rho signaling by other Sec14-containing Rho activators.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Cell invasion during competitive growth of polycrystalline solidification patterns

Abstract Spatially extended cellular and dendritic array structures forming during solidification processes such as casting, welding, or additive manufacturing are generally polycrystalline. Both the array structure within each grain and the larger scale grain structure determine the performance of many structural alloys. How those two structures coevolve during solidification remains poorly understood. By in situ observations of microgravity alloy solidification experiments onboard the International Space Station, we have discovered that individual cells from one grain can unexpectedly invade a nearby grain of different misorientation, either as a solitary cell or as rows of cells. This invasion process causes grains to interpenetrate each other and hence grain boundaries to adopt highly convoluted shapes. Those observations are reproduced by phase-field simulations further demonstrating that invasion occurs for a wide range of misorientations. Those results fundamentally change the traditional conceptualization of grains as distinct regions embedded in three-dimensional space.

36 MATERIALS SCIENCE↗
DOE OSTI2023

A fluorinated cation introduces new interphasial chemistries to enable high-voltage lithium metal batteries

Abstract Fluorides have been identified as a key ingredient in interphases supporting aggressive battery chemistries. While the precursor for these fluorides must be pre-stored in electrolyte components and only delivered at extreme potentials, the chemical source of fluorine so far has been confined to either negatively-charge anions or fluorinated molecules, whose presence in the inner-Helmholtz layer of electrodes, and consequently their contribution to the interphasial chemistry, is restricted. To pre-store fluorine source on positive-charged species, here we show a cation that carries fluorine in its structure is synthesized and its contribution to interphasial chemistry is explored for the very first time. An electrolyte carrying fluorine in both cation and anion brings unprecedented interphasial chemistries that translate into superior battery performance of a lithium-metal battery, including high Coulombic efficiency of up to 99.98%, and Li 0 -dendrite prevention for 900 hours. The significance of this fluorinated cation undoubtedly extends to other advanced battery systems beyond lithium, all of which universally require kinetic protection of highly fluorinated interphases.

25 ENERGY STORAGE↗
DOE OSTI2024

Effect of solid-electrolyte pellet density on failure of solid-state batteries

Abstract Despite the potentially higher energy density and improved safety of solid-state batteries (SSBs) relative to Li-ion batteries, failure due to Li-filament penetration of the solid electrolyte and subsequent short circuit remains a critical issue. Herein, we show that Li-filament growth is suppressed in solid-electrolyte pellets with a relative density beyond ~95%. Below this threshold value, however, the battery shorts more easily as the density increases due to faster Li-filament growth within the percolating pores in the pellet. The microstructural properties (e.g., pore size, connectivity, porosity, and tortuosity) of $$75\%{{{{{\rm{L}}}}}}{{{{{{\rm{i}}}}}}}_{2}{{{{{\rm{S}}}}}}-25\%{{{{{{\rm{P}}}}}}}_{2}{{{{{{\rm{S}}}}}}}_{5}$$ 75 % L i 2 S − 25 % P 2 S 5 with various relative densities are quantified using focused ion beam–scanning electron microscopy tomography and permeability tests. Furthermore, modeling results provide details on the Li-filament growth inside pores ranging from 0.2 to 2 μm in size. Our findings improve the understanding of the failure modes of SSBs and provide guidelines for the design of dendrite-free SSBs.

25 ENERGY STORAGE↗
DOE OSTI2024

A self-healing plastic ceramic electrolyte by an aprotic dynamic polymer network for lithium metal batteries

Abstract Oxide ceramic electrolytes (OCEs) have great potential for solid-state lithium metal (Li 0 ) battery applications because, in theory, their high elastic modulus provides better resistance to Li 0 dendrite growth. However, in practice, OCEs can hardly survive critical current densities higher than 1 mA/cm 2 . Key issues that contribute to the breakdown of OCEs include Li 0 penetration promoted by grain boundaries (GBs), uncontrolled side reactions at electrode-OCE interfaces, and, equally importantly, defects evolution (e.g., void growth and crack propagation) that leads to local current concentration and mechanical failure inside and on OCEs. Here, taking advantage of a dynamically crosslinked aprotic polymer with non-covalent –CH 3 ⋯CF 3 bonds, we developed a plastic ceramic electrolyte (PCE) by hybridizing the polymer framework with ionically conductive ceramics. Using in-situ synchrotron X-ray technique and Cryogenic transmission electron microscopy (Cryo-TEM), we uncover that the PCE exhibits self-healing/repairing capability through a two-step dynamic defects removal mechanism. This significantly suppresses the generation of hotspots for Li 0 penetration and chemomechanical degradations, resulting in durability beyond 2000 hours in Li 0 -Li 0 cells at 1 mA/cm 2 . Furthermore, by introducing a polyacrylate buffer layer between PCE and Li 0 -anode, long cycle life >3600 cycles was achieved when paired with a 4.2 V zero-strain cathode, all under near-zero stack pressure.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Observation of nanoparticle coalescence during core-shell metallic nanowire growth in colloids via nanoscale imaging

The surface morphology and shape of crystalline nanowires significantly influence their functional properties, including phonon transport, electrocatalytic performance, to name but a few. However, the kinetic pathways driving these morphological changes remain underexplored due to challenges in real-space and real-time imaging at single-particle and atomic resolutions. This study investigates the dynamics of shell (Au, Pd, Pt, Fe, Cu, Ni) deposition on AuAg alloy seed nanowires during core-shell formation. By using chiral/non-chiral seed nanowires, advanced imaging techniques, including liquid-phase transmission electron microscopy (LPTEM), cryogenic TEM, and three-dimensional electron tomography, a three-step deposition process is revealed: heterogeneous nucleation, nanoparticle attachment, and coalescence. It is found that colloidal Ostwald ripening, metal reactivity, and deposition amount modulate nanoparticle size and surface roughness, shaping final morphologies. Noble metal nanoparticles (Au, Ag, Pd, Pt) coalesce with seed nanowire along the 〈111〉 direction, distinct from that of other metals. These findings are consistent across different metals, including Ru, Cu, Fe, and Ni, highlighting the hypothesis of these processes in nanowire formation. These findings enhance traditional crystallographic theories and provide a framework for designing nanowire morphology. Additionally, our imaging techniques may be applied to investigate phenomena like electrodeposition, dendrite growth in batteries, and membrane deformation.

Yang, Dahai↗
DOE OSTI2021

Microstructural impacts on ionic conductivity of oxide solid electrolytes from a combined atomistic-mesoscale approach

Abstract Although multiple oxide-based solid electrolyte materials with intrinsically high ionic conductivities have emerged, practical processing and synthesis routes introduce grain boundaries and other interfaces that can perturb primary conduction channels. To directly probe these effects, we demonstrate an efficient and general mesoscopic computational method capable of predicting effective ionic conductivity through a complex polycrystalline oxide-based solid electrolyte microstructure without relying on simplified equivalent circuit description. We parameterize the framework for Li 7- x La 3 Zr 2 O 12 (LLZO) garnet solid electrolyte by combining synthetic microstructures from phase-field simulations with diffusivities from molecular dynamics simulations of ordered and disordered systems. Systematically designed simulations reveal an interdependence between atomistic and mesoscopic microstructural impacts on the effective ionic conductivity of polycrystalline LLZO, quantified by newly defined metrics that characterize the complex ionic transport mechanism. Our results provide fundamental understanding of the physical origins of the reported variability in ionic conductivities based on an extensive analysis of literature data, while simultaneously outlining practical design guidance for achieving desired ionic transport properties based on conditions for which sensitivity to microstructural features is highest. Additional implications of our results are discussed, including a possible connection between ion conduction behavior and dendrite formation.

25 ENERGY STORAGE↗
DOE OSTI2024

Corrosion evaluation of Al-Cu-Mn-Zr cast alloys in 3.5% NaCl solution

Corrosion behavior of cast Al-Cu-Mn-Zr (ACMZ) and RR350 alloys was compared to a cast 319 alloy in 3.5 wt.% NaCl. After 168 h immersion, ACMZ and RR350 alloys suffered from preferential attack adjacent to intermetallic particles decorated at grain boundaries while the attack in 319 occurred in eutectic Al-Si dendritic boundaries. Electrochemical data allowed semiquantitative comparison of alloy resistance to corrosion initiation, and ACMZ type alloys, including RR350 and three alloys with higher Cu, were considered more resistant than 319 due to the absence of deleterious Si particles. In case of 319, such Si particles presumably drove higher micro-galvanic influence to initiate and sustain Al corrosion. With lower susceptibility to corrosion initiation, ACMZ alloys should exhibit higher or at minimum similar resistance compared to cast 319.

36 MATERIALS SCIENCE↗
DOE OSTI2020

High-power Mg batteries enabled by heterogeneous enolization redox chemistry and weakly coordinating electrolytes

Magnesium batteries have long been pursued as potentially low-cost, high-energy and safe alternatives to Li-ion batteries. However, Mg 2+ interacts strongly with electrolyte solutions and cathode materials, leading to sluggish ion dissociation and diffusion, and consequently low power output. Here we report a heterogeneous enolization chemistry involving carbonyl reduction (C=O ↔ C–O-), which bypasses the dissociation and diffusion difficulties, enabling fast and reversible redox processes. This kinetically favoured cathode is coupled with a tailored, weakly coordinating boron cluster-based electrolyte that allows for dendrite-free Mg plating/stripping at a current density of 20 mA cm -2 . The combination affords a Mg battery that delivers a specific power of up to 30.4 kW kg -1 , nearly two orders of magnitude higher than that of state-of-the-art Mg batteries. Here, the cathode and electrolyte chemistries elucidated here propel the development of magnesium batteries and would accelerate the adoption of this low-cost and safe battery technology.

25 ENERGY STORAGE↗
DOE OSTI2021

Solid-state rigid-rod polymer composite electrolytes with nanocrystalline lithium ion pathways

A critical challenge for next-generation lithium-based batteries lies in development of electrolytes that enable thermal safety along with use of high-energy-density electrodes. We describe molecular ionic composite (MIC) electrolytes based on an aligned liquid crystalline polymer combined with ionic liquids and concentrated Li salt. This high strength (200 MPa) and non-flammable solid electrolyte possesses outstanding Li + conductivity (1 mS cm -1 at 25 °C) and electrochemical stability (5.6 V vs Li|Li + ) while suppressing dendrite growth and exhibiting low interfacial resistance (32 Ω cm 2 ) and overpotentials (≤ 120 mV @ 1 mA cm -2 ) during Li symmetric cell cycling. A heterogeneous salt doping process modifies a locally ordered polymer-ion assembly to incorporate an inter-grain network filled with defective LiFSI & LiBF 4 nanocrystals, strongly enhancing Li + conduction. Furthermore, this modular material fabrication platform shows promise for safe and high-energy-density energy storage and conversion applications, incorporating the fast transport of ceramic-like conductors with the superior flexibility of polymer electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2023

Probing lithium mobility at a solid electrolyte surface

Abstract Solid-state electrolytes overcome many challenges of present-day lithium ion batteries, such as safety hazards and dendrite formation 1,2 . However, detailed understanding of the involved lithium dynamics is missing due to a lack of in operando measurements with chemical and interfacial specificity. Here we investigate a prototypical solid-state electrolyte using linear and nonlinear extreme-ultraviolet spectroscopies. Leveraging the surface sensitivity of extreme-ultraviolet-second-harmonic-generation spectroscopy, we obtained a direct spectral signature of surface lithium ions, showing a distinct blueshift relative to bulk absorption spectra. First-principles simulations attributed the shift to transitions from the lithium 1 s state to hybridized Li- s /Ti- d orbitals at the surface. Our calculations further suggest a reduction in lithium interfacial mobility due to suppressed low-frequency rattling modes, which is the fundamental origin of the large interfacial resistance in this material. Our findings pave the way for new optimization strategies to develop these electrochemical devices via interfacial engineering of lithium ions.

25 ENERGY STORAGE↗
DOE OSTI2026

Heterogeneous doping via nanoscale coating impacts the mechanics of Li intrusion in brittle solid electrolytes

Lithium dendrite intrusion in solid-state batteries limits fast charging and causes short-circuiting, yet the underlying regulating mechanisms are not well-understood. Here, in this work, we discover that heterogeneous Ag + doping dramatically affects lithium intrusion into Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 (LLZO), a brittle solid electrolyte. Nanoscale Ag + doping is achieved by thermally annealing a 3-nm-thick metallic coating on LLZO, inducing Ag–Li ion exchange and Ag diffusion into grains and grain boundaries. Density functional theory calculations and experimental characterization show negligible impact on the electronic properties and surface wettability from Ag + incorporation. Mechanically, nanoindentation experiments show a fivefold increase in the mechanical force required to fracture the surface Ag + -doped LLZO, indicating substantial doping-induced surface toughening. Operando microprobe scanning electron microscopy experiments show that the Ag + -doped LLZO surface exhibits improved lithium plating at >250 mA cm −2 and an electroplating diameter that is expanded by over fourfold, even under an extreme indentation stress of 3 GPa. This demonstrates enhanced defect tolerance in LLZO, rather than electronic or adhesion effects. Our study reveals a chemo-mechanical mechanism via surface heterogeneous doping, complementing present bulk design rules to minimize mechanical failures in solid-state batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Superionic conducting vacancy-rich β-Li 3 N electrolyte for stable cycling of all-solid-state lithium metal batteries

The advancement of all-solid-state lithium metal batteries requires breakthroughs in solid-state electrolytes (SSEs) for the suppression of lithium dendrite growth at high current densities and high capacities (>3 mAh cm -2 ) and innovation of SSEs in terms of crystal structure, ionic conductivity and rigidness. Here we report a superionic conducting, highly lithium-compatible and air-stable vacancy-rich β-Li 3 N SSE. This vacancy-rich β-Li 3 N SSE shows a high ionic conductivity of 2.14 × 10 -3 S cm -1 at 25 °C and surpasses almost all the reported nitride-based SSEs. A Li- and N-vacancy-mediated fast lithium-ion migration mechanism is unravelled regarding vacancy-triggered reduced activation energy and increased mobile lithium-ion population. All-solid-state lithium symmetric cells using vacancy-rich β-Li 3 N achieve breakthroughs in high critical current densities up to 45 mA cm -2 and high capacities up to 7.5 mAh cm -2 , and ultra-stable lithium stripping and plating processes over 2,000 cycles. The high lithium compatibility mechanism of vacancy-rich β-Li 3 N is unveiled as intrinsic stability to lithium metal. In addition, β-Li 3 N possesses excellent air stability through the formation of protection surfaces. All-solid-state lithium metal batteries using the vacancy-rich β-Li 3 N as SSE interlayers and lithium cobalt oxide (LCO) and Ni-rich LiNi 0.83 Co 0.11 Mn 0.06 O 2 (NCM83) cathodes exhibit excellent battery performance. Extremely stable cycling performance is demonstrated with high capacity retentions of 82.05% with 95.2 mAh g -1 over 5,000 cycles at 1.0 C for LCO and 92.5% with 153.6 mAh g -1 over 3,500 cycles at 1.0 C for NCM83. Utilizing the vacancy-rich β-Li 3 N SSE and NCM83 cathodes, the all-solid-state lithium metal batteries successfully accomplished mild rapid charge and discharge rates up to 5.0 C, retaining 60.47% of the capacity. Notably, these batteries exhibited a high areal capacity, registering approximately 5.0 mAh cm -2 for the compact pellet-type cells and around 2.2 mAh cm -2 for the all-solid-state lithium metal pouch cells.

25 ENERGY STORAGE↗
DOE OSTI2026

Aqueous electrolyte solutions with anion-bridged secondary solvation sheaths for highly efficient zinc metal batteries

Aqueous zinc metal batteries are low-cost electrochemical devices suitable for safe grid energy storage. However, water decomposition and Zn dendrite formation detrimentally affect their coulombic efficiency. Conventional aqueous electrolyte solutions, with a concentration around 1 M, are cost-effective and exhibit high bulk ionic conductivity but cannot form a stable solid electrolyte interphase. Water-in-salt and aqueous-organic hybrid electrolyte solutions can form robust solid electrolyte interphases, but they are not kinetically efficient and cost-effective. Here, to circumvent these issues, we design variously concentrated aqueous electrolyte solutions using several salts with different donor numbers to extend anion coordination into the secondary solvation sheath. We show that salt-derived anions with donor number > 18 enter the Zn2+ first solvation sheath, and ensure a strong binding energy between the Zn2+(H2O)5-anion nanometric clusters and water molecules in the secondary solvation sheath. In particular, 2 M aqueous electrolyte solutions containing fluorinated anions exhibit bulk ionic conductivities of 26-35 mS cm−1 at 25 °C and form a ZnF2-rich solid electrolyte interphase. When tested in Zn||NaV3O8·1.5H2O Swagelok cells, the best-performing electrolyte solution enables an average coulombic efficiency of 99.99% for 1,000 cycles at 1.5 mA cm−2, corresponding to an initial specific energy of 130 Wh kg−1 (based on the combined weight of the positive and negative electrodes).

25 ENERGY STORAGE↗
DOE OSTI2020

A disordered rock salt anode for fast-charging lithium-ion batteries

Rechargeable lithium-ion batteries with high energy density that can be safely charged and discharged at high rates are desirable for electrified transportation and other applications. However, the sub-optimal intercalation potentials of current anodes result in a trade-off between energy density, power and safety. In this paper we report that disordered rock salt Li 3+ x V 2 O 5 can be used as a fast-charging anode that can reversibly cycle two lithium ions at an average voltage of about 0.6 volts versus a Li/Li + reference electrode. The increased potential compared to graphite reduces the likelihood of lithium metal plating if proper charging controls are used, alleviating a major safety concern (short-circuiting related to Li dendrite growth). In addition, a lithium-ion battery with a disordered rock salt Li 3 V 2 O 5 anode yields a cell voltage much higher than does a battery using a commercial fast-charging lithium titanate anode or other intercalation anode candidates (Li 3 VO 4 and LiV 0.5 Ti 0.5 S 2 ). Further, disordered rock salt Li 3 V 2 O 5 can perform over 1,000 charge–discharge cycles with negligible capacity decay and exhibits exceptional rate capability, delivering over 40 per cent of its capacity in 20 seconds. We attribute the low voltage and high rate capability of disordered rock salt Li 3 V 2 O 5 to a redistributive lithium intercalation mechanism with low energy barriers revealed via ab initio calculations. This low-potential, high-rate intercalation reaction can be used to identify other metal oxide anodes for fast-charging, long-life lithium-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

Dynamic spatial progression of isolated lithium during battery operations

The increasing demand for next-generation energy storage systems necessitates the development of high-performance lithium batteries. Unfortunately, current Li anodes exhibit rapid capacity decay and a short cycle life, owing to the continuous generation of solid electrolyte interface and isolated Li (i-Li). The formation of i-Li during the nonuniform dissolution of Li dendrites leads to a substantial capacity loss in lithium batteries under most testing conditions. Because i-Li loses electrical connection with the current collector, it has been considered electrochemically inactive or ‘dead’ in batteries. In this work, contradicting this commonly accepted presumption, we show that i-Li is highly responsive to battery operations, owing to its dynamic polarization to the electric field in the electrolyte. Simultaneous Li deposition and dissolution occurs on two ends of the i-Li, leading to its spatial progression toward the cathode (anode) during charge (discharge). Revealed by our simulation results, the progression rate of i-Li is mainly affected by its length, orientation and the applied current density. Moreover, we successfully demonstrate the recovery of i-Li in Cu–Li cells with >100% Coulombic efficiency and realize LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC)–Li full cells with extended cycle life.

25 ENERGY STORAGE↗