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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 1,693 records · Page 94
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Stable Co-valorization of Carbon Dioxide and Methane via Dynamic Reconstruction of a Metal Oxide Solid Solution Catalyst

Dry reforming of methane (DRM) is a process that converts two greenhouse gases (methane and carbon dioxide) into syngas, a mixture of H 2 and CO, that can lead to a variety of value-added chemicals. Owing to its endothermic nature, high reaction temperatures up to 800 °C are typically required and the grand challenge lies in developing robust catalysts without sintering and coking-induced deactivation during the long-term on-stream operation. Towards this aim, herein, a robust complex oxide-supported NiCu alloy catalyst was generated in situ during DRM. By leveraging the configurational stability of a solid oxide solution precursor, tightly anchored NiCu bimetallic nanoparticles were in situ exsoluted and acted as the active sites in DRM. The as-afforded catalyst exhibited stable performance for DRM due to the ability to repel coke off the surface as the reaction proceeds. Kinetic experiments along with top surface characterization detail the reconstruction behavior of the solid oxide solution under DRM reaction conditions. In conclusion, the fundamental insights from this work provide guidance on generating resistant and flexible catalysts via in situ active sites formation from easily synthesized metal oxide solid solutions.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Condensed Phase Deactivation of Solid Brønsted Acids in the Dehydration of Fructose to Hydroxymethylfurfural

Catalyst deactivation resulting from the hydrothermal leaching of sulfonic acid residues and the deposition of carbonaceous residues was studied using condensed phase flow reactor experiments along with state-of-the-art solid-state NMR. Several commercially available sulfonic acid-containing heterogeneous Brønsted acids were compared by measuring the rates of sulfonic acid breakdown at hydrothermal flow conditions of 160 °C. Amberlyst 45 was found to show higher hydrothermal stability when compared to both Nafion and Amberlyst 15, with <10% loss in acidity after 48 h. The dehydration reaction of fructose to hydroxymethylfurfural (HMF) was used as a model system to compare deactivation rates from carbon deposition (fouling) to those from sulfur leaching, and deactivation from fouling was shown to be dramatically faster than that from sulfonic acid leaching alone. Fouling rates were then investigated in greater detail by comparing the influence of several factors including reactant, solvent, residence time, and feed concentration. The only successful approach to minimize fouling was the use of a polar aprotic solvent [dimethyl sulfoxide (DMSO)] with dilute (50 mM) reactant streams. In aqueous systems, operating the reactor in a regime with low conversion conditions (short residence times) does not significantly improve the longevity of the catalyst. Spent catalysts were characterized using 13C solid-state NMR spectroscopy enhanced by dynamic nuclear polarization. Additionally, in situ 1H and 13C high-resolution magic angle spinning (HR-MAS) solid-state NMR spectroscopies were used to investigate the solvent influence at the catalyst interface. The HR-MAS NMR studies showed that in polar aprotic solvents, the increased acidity leads to greater selectivity toward HMF; more importantly, that the dehydration products do not readily adhere to the surface in DMSO, in contrast to their behavior in water. The results demonstrate that more active and longer-lived acid catalysts could be obtained by tuning the solvent and surface polarity to allow for efficient desorption of products, thereby reducing the catalyst deactivation that occurs due to fouling.

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

Electrochemical Healing of Dendrites in Garnet-Based Solid Electrolytes

Garnet oxides are a promising material family for solid-state batteries (SSBs). Dendrite formation in solid electrolytes critically limits the applicability of SSBs because of limiting Coulombic efficiency and power capability. In this study, the authors report operando electrochemical healing of dendrites in a garnet-based solid electrolyte (SE). Dendrites were deliberately formed at high operational current density (2 mA cm –2 ) beyond the critical current density (0.55 mA cm –2 ) of the used garnet SE. Electrochemical impedance spectroscopy and scanning electron microscopy were used to confirm dendrite growth in the SE. Dendrites were subsequently healed electrochemically via plating and stripping at 20 and 1 μA cm –2 current densities. Removal of dendrites was shown by an increase in bulk and interfacial resistance and a progressive increase in polarization during galvanostatic plating and stripping. High local current density at the dendrite tips was identified as the mechanism for preferentially removing dendrites electrochemically. The dendrite detection and healing methods discussed here are crucial for extending the life of SSBs.

25 ENERGY STORAGE↗
DOE OSTI2022

Quantifying Graphite Solid-Electrolyte Interphase Chemistry and its Impact on Fast Charging

The solid-electrolyte interphase (SEI) enables the remarkable capacity retention of lithium-ion batteries, yet a comprehensive quantitative description of the SEI composition remains elusive. Using a combination of differential electrochemical mass spectrometry and mass spectrometry titration, we quantify graphite SEI components formed under electrolytes of varying salt concentrations. We find that, regardless of salt concentration, a conversion of initially deposited lithium ethylene dicarbonate to monocarbonates (likely lithium ethylene monocarbonate) and noncarbonate species occurs, and the extent of this conversion increases with electrolyte aging. Here, we additionally demonstrate that as the concentration increases (up to 2.0 M LiPF6), the SEI becomes progressively thinner with more LiF and less solid carbonates deposited. Finally, we reveal that less dead lithium formation and less solid carbonate deposition occur during prolonged fast charging for higher-concentration electrolytes. Because of the advantages imparted by a thinner SEI, the onset state of charge for lithium plating for the 2.0 M electrolyte is later than that predicted by a standard electrochemical model, underscoring the importance of explicit SEI effects in future electrochemical models.

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

Molecular Engineering of Biorefining Lignin Waste for Solid-State Electrolyte

Lignin is the second most abundant renewable biopolymer on Earth but also a waste in both the paper industry and lignocellulosic biorefineries. Recently, lignin valorization has been extensively sought after to return economics, enhance carbon efficiency, and improve the bioeconomy, but the commercial value and size compatibility still hinder its applications. In this study, we developed a facile strategy to apply lignin waste into a solid-state electrolyte (SSE), which represents a safe next generation energy storage. Here, lignin was grafted with polyethylene glycol (PEG), an efficient lithium-ion (Li + ) conductive polymer, to enable its ion conduction. The synthesized PEG-g-lignin was mixed with poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) and PEG-g-lignin-based bis(trifluoromethanesulfonyl)imide (LiTFSI) to prepare a solid polymer electrolyte (SPE), which has an ionic conductivity of 2.5 × 10 –5 S/cm at 25 °C. This result was further enhanced to 6.5 × 10 –5 S/cm by adding an ion-conductive ceramic of Li 6.4 La 3 Ga 0.2 Zr 2 O 12 (LLGZO), which is referred to as composite polymer electrolyte (CPE). These data represent the highest ones among reported polymer-based SSE. A mechanistic study by using 2D HSQC NMR revealed that PEG-g-lignin has increased ether type β–O–4 linkages that can promote the interchain hopping of Li+ between lignin polymer chains, and 31 P NMR revealed that the lignin phenolic end can be associated by Li + . Moreover, the abundant aromatic moieties and methoxyl in PEG-g-lignin also enhanced Li + association and improved its ionic conductivity. The superior ionic conductivity of PEG-g-lignin-based SSE can enable massive applications of this biorefining waste in all-solid-state lithium batteries (ASSLBs), which has potential to promote the energy sector by promoting the bioeconomy and enhancing the renewability and sustainability of future energy storage.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

A graph-based network for predicting chemical reaction pathways in solid-state materials synthesis

Abstract Accelerated inorganic synthesis remains a significant challenge in the search for novel, functional materials. Many of the principles which enable “synthesis by design” in synthetic organic chemistry do not exist in solid-state chemistry, despite the availability of extensive computed/experimental thermochemistry data. In this work, we present a chemical reaction network model for solid-state synthesis constructed from available thermochemistry data and devise a computationally tractable approach for suggesting likely reaction pathways via the application of pathfinding algorithms and linear combination of lowest-cost paths in the network. We demonstrate initial success of the network in predicting complex reaction pathways comparable to those reported in the literature for YMnO 3 , Y 2 Mn 2 O 7 , Fe 2 SiS 4 , and YBa 2 Cu 3 O 6.5 . The reaction network presents opportunities for enabling reaction pathway prediction, rapid iteration between experimental/theoretical results, and ultimately, control of the synthesis of solid-state materials.

36 MATERIALS SCIENCE↗
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

Single-phase local-high-concentration solid polymer electrolytes for lithium-metal batteries

Solid polymers are promising electrolytes for Li-metal batteries, but they have limitations: they cannot simultaneously achieve high ionic conductivity, good mechanical strength and compatibility with high-voltage cathodes while suppressing Li dendrites. Here, we design a class of locally high-concentration solid polymer electrolytes based on polymer blends, which are termed Li-polymer in F diluter (LPIFD). The Li-polymer (polymer-in-salt) ensures continuous Li-ion conduction channels and contributes to the solid electrolyte interphase (SEI), and the F diluter (inert fluorinated polymer) adds mechanical strength. Studies reveal that a single-phase LPIFD, which is based on a miscible polymer blend, lacks phase boundaries and forms an organic-less and LiF-rich SEI, effectively suppressing lithium dendrites. The single-phase LPIFD delivers ionic conductivity of 3.0 x 10 -4 S cm -1 and enables the Li anode to reach a high coulombic efficiency of 99.1% and a critical current density of 3.7 mA cm -2 . Furthermore, the ability to form an F-rich cathode electrolyte interphase allows LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li cells to achieve a cycle life of 450 cycles at a high operating voltage of 4.5 V. In conclusion, this design will inspire efforts to commercialize polymer electrolytes for high-energy Li-metal batteries.

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

Ultrafast high-harmonic spectroscopy of solids

High-harmonic spectroscopy, an ultrafast all-optical technique initially conceptualized in atomic and molecular systems, has now emerged as a powerful platform for studying the structure and dynamics of condensed matter. Unlike that in the gas phase, solid-state high-harmonic generation relies on the fundamental response from high atomic density and periodicity, leading to interband transitions and coherent driving of electrons and holes in their respective bands. These mechanisms make high-harmonic spectroscopy particularly sensitive to the electronic band structure, topological properties and many-body correlations in condensed media. An advantage of high-harmonic spectroscopy over other spectroscopic methods is its ability to probe ultrafast phenomena, capturing femto- to attosecond dynamics of multi-band and strongly correlated electron interactions in solids. Furthermore, in this Review, we discuss the latest experimental and theoretical advances in ultrafast high-harmonic spectroscopy of solids and provide perspectives for future research in this field.

High-harmonic generation↗
DOE OSTI2025

Electrolyte strategies for practically viable all-solid-state lithium-sulfur batteries

All-solid-state lithium-sulfur batteries are a promising platform due to their high gravimetric energy density and enhanced safety. However, they face numerous challenges that currently obstruct commercial adoption. The key to overcoming these challenges lies in the rational selection and targeted development of solid-state electrolytes, where different materials classes present distinct trade-offs between performance and practicality. We assert that sulfide electrolytes offer the best compatibility with the cathode and anode requirements for practical sulfur cells, with halides and borohydrides also showing potential for use in the cathode with further development. We provide cell-level target parameters to ensure that the field moves consistently towards commercial relevance. Looking forward, we call for the adoption of the chlorinated argyrodite with a composition range of Li 6-x PS 5-x Cl 1+x (x = 0 - 0.5) as a standardized solid-state electrolyte to enable rigorous benchmarking across the field and accelerate battery development.

25 ENERGY STORAGE↗
DOE OSTI2022

The impact of residual solvent on catholyte performance in solid-state batteries

All-solid-state batteries (ASSBs) are attractive due to their safety, use of the Li metal anode, high energy density, and innovative processing routes. However, high interfacial resistance, especially on the cathode side, is one of the major challenges for commercialization of ASSBs. Catholyte, either a liquid or solid, is added to lower the cathode/electrolyte interfacial resistance. In this study, we find that residual N-methylpyrrolidone solvent remaining in a PVDF/LiTFSI solid polymer catholyte after incomplete drying can dramatically lower the interfacial resistance between the Li 6.25 Al 0.25 La 3 Zr 2 O 12 electrolyte and LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathode-active material. Cells with varying amounts of residual solvent are compared to optimize the residual solvent loading. With moderate residual solvent, the discharge capacity reaches 142 mA h g -1 when cycled at 25 °C and 0.5 C and the capacity retention is 60.5% after 125 cycles. Discharge capacity retention is improved at -10 °C. The conductivity of the free-standing PVDF/LiTFSI film, mimicking the PVDF/LiTFSI catholyte, verifies the role of residual NMP in the cathode. Finally, this study demonstrates the possibility of widely differing results for ASSBs when the cathode is not completely dried. Also, it provides a hint for a potential method to lower the cathode/electrolyte interfacial resistance.

25 ENERGY STORAGE↗
DOE OSTI2025

Interface diagnostics platform for thin-film solid-state batteries

Understanding the impedances of battery materials and their interfaces remains a major challenge, usually addressed by electrochemical impedance spectroscopy (EIS) where frequency-dependent complex impedance of full battery cells is measured and then modeled by a network of connected electrical elements. As conventionally applied, this approach produces ambiguity in that (1) multiple different network configurations may fit the data convincingly and (2) the method offers no direct association of the electrical elements with physical features of the battery. Here we present a new methodology that resolves both sources of ambiguity, enabled by expanding the experimental scope to directly inform the configuration of elements and their parameters in the network model. We demonstrate this methodology using thin film fabrication of solid state battery devices patterned by shadow masked sputter deposition, so that diagnostic devices corresponding to individual interface and material components can be fabricated simultaneously with full cell batteries. EIS models for the diagnostic devices can then be connected to form full cell networks whose topology matches the well-known physical configuration of the battery. When connected in this way, the full network model – made from connecting the diagnostic device EIS models – fits the full cell EIS data. For the case of a thin film solid state battery composed of amorphous silicon anode, lithium phosphorus oxynitride (LiPON) solid electrolyte, and lithium vanadium oxide (Li x V 2 O 5 ) cathode, we show that the approach allows us to identify ionic impedance/conductivity of the cathode/electrolyte as a limiting impedance and the anode/electrolyte interface cycling instability as a primary degradation factor.

25 ENERGY STORAGE↗
DOE OSTI2013

Effect of confinement on the solid-liquid coexistence of Lennard-Jones Fluid

The solid-liquid coexistence of a Lennard-Jones fluid confined in slit pores of variable pore size, H, is studied using molecular dynamics simulations. Three-stage pseudo-supercritical transformation path of Grochola [J. Chem. Phys. 120(5), 2122 (2004)] and multiple histogram reweighting are employed for the confined system, for various pore sizes ranging from 20 to 5 molecular diameters, to compute the solid-liquid coexistence. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid-liquid phases under confinement via one or more intermediate states without any first order phase transition among them. Thermodynamic melting temperature is found to oscillate with wall separation, which is in agreement with the behavior seen for kinetic melting temperature evaluated in an earlier study. However, thermodynamic melting temperature for almost all wall separations is higher than the bulk case, which is contrary to the behavior seen for the kinetic melting temperature. The oscillation founds to decay at around H = 12, and beyond that pore size dependency of the shift in melting point is well represented by the Gibbs-Thompson equation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Space charge limited conduction in ultrathin PbS quantum dot solid diodes

As a simple and direct characterization of carrier transport in nanocrystal quantum dot (NQD) solids, current-voltage characterization of ultrathin diodes is proposed. We found the space charge limited conduction (SCLC) behavior in ultrathin PbS NQD diodes with active layer thickness half of the full depletion width; and extracted hole concentrations in the order of 10{sup 15} cm{sup −3}, hole mobilities from 10{sup −4} to 10{sup −5} cm{sup 2}/Vs, trap energy depths varying from 140 meV to 200 meV, and volume trap density around 10{sup 17} cm{sup −3} for thin films with NQDs of diameters 3.3 and 3.6 nm, respectively. We further discuss the validity of applying SCLC to the NQD solids based diodes and the implications of the extracted parameters extensively. Proposed characterization method here is a direct measure of carrier transport in solar cell structures which could provide exact directions in NQD solids based solar cell fabrication and modeling.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Unraveling resistive versus collisional contributions to relativistic electron beam stopping power in cold-solid and in warm-dense plasmas

We present results on laser-driven relativistic electron beam propagation through aluminum samples, which are either solid and cold or compressed and heated by laser-induced shock. A full numerical description of fast electron generation and transport is found to reproduce the experimental absolute K{sub α} yield and spot size measurements for varying target thicknesses, and to sequentially quantify the collisional and resistive electron stopping powers. The results demonstrate that both stopping mechanisms are enhanced in compressed Al samples and are attributed to the increase in the medium density and resistivity, respectively. For the achieved time- and space-averaged electronic current density, 〈j{sub h}〉∼8×10{sup 10} A/cm{sup 2} in the samples, the collisional and resistive stopping powers in warm and compressed Al are estimated to be 1.5 keV/μm and 0.8 keV/μm, respectively. By contrast, for cold and solid Al, the corresponding estimated values are 1.1 keV/μm and 0.6 keV/μm. Prospective numerical simulations involving higher j{sub h} show that the resistive stopping power can reach the same level as the collisional one. In addition to the effects of compression, the effect of the transient behavior of the resistivity of Al during relativistic electron beam transport becomes progressively more dominant, and for a significantly high current density, j{sub h}∼10{sup 12} A/cm{sup 2}, cancels the difference in the electron resistive stopping power (or the total stopping power in units of areal density) between solid and compressed samples. Analytical calculations extend the analysis up to j{sub h}=10{sup 14} A/cm{sup 2} (representative of the full-scale fast ignition scenario of inertial confinement fusion), where a very rapid transition to the Spitzer resistivity regime saturates the resistive stopping power, averaged over the electron beam duration, to values of ∼1 keV/μm.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Mechanism of dilute-spin-exchange in solid-state NMR

In the stationary, aligned samples used in oriented sample (OS) solid-state NMR, {sup 1}H-{sup 1}H homonuclear dipolar couplings are not attenuated as they are in magic angle spinning solid-state NMR; consequently, they are available for participation in dipolar coupling-based spin-exchange processes. Here we describe analytically the pathways of {sup 15}N-{sup 15}N spin-exchange mediated by {sup 1}H-{sup 1}H homonuclear dipolar couplings. The mixed-order proton-relay mechanism can be differentiated from the third spin assisted recoupling mechanism by setting the {sup 1}H to an off-resonance frequency so that it is at the “magic angle” during the spin-exchange interval in the experiment, since the “magic angle” irradiation nearly quenches the former but only slightly attenuates the latter. Experimental spectra from a single crystal of N-acetyl leucine confirm that this proton-relay mechanism plays the dominant role in {sup 15}N-{sup 15}N dilute-spin-exchange in OS solid-state NMR in crystalline samples. Remarkably, the “forbidden” spin-exchange condition under “magic angle” irradiation results in {sup 15}N-{sup 15}N cross-peaks intensities that are comparable to those observed with on-resonance irradiation in applications to proteins. The mechanism of the proton relay in dilute-spin-exchange is crucial for the design of polarization transfer experiments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Spectroscopy of Mn atoms isolated in solid {sup 4}He

We present an experimental study of the laser-induced luminescence spectra of Mn atoms in solid helium matrices. We observe transitions of the valence electron and of inner-shell electrons. We find that the Mn-He interaction perturbs the inner-shell transitions to a lesser extent than the valence-electron transitions. The observed lineshapes of the inner-shell transitions of Mn are similar to those of an inner-shell transition in Ba studied earlier. At the same time, they are more strongly perturbed than the corresponding transitions in Au and Cu under the same conditions. We suggest a qualitative explanation of these observations based on the atomic bubble model. Our results also suggest that the inner-shell transitions of Mn in solid He are more strongly perturbed than the same lines of Mn isolated in solid Ar or Kr matrices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗