A Co- and Ni-Free P2/O3 Biphasic Lithium Stabilized Layered Oxide for Sodium-Ion Batteries and its Cycling Behavior
Explore the source record for details and available documents.
99 GENERAL AND MISCELLANEOUS↗
SEARCH · Engineering Papers
Results for “Structure preservation”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Historic Buildings Report: Five-Year Preservation Planning for Manhattan Project National Historical Park Sites
This report offers a preservation maintenance plan for the next five years for buildings and structures included in or eligible for inclusion in the Manhattan Project National Historical Park at Los Alamos National Laboratory. There are twenty-three buildings, structures, and ruins of previously standing buildings covered within this report. Many of the preservation maintenance issues addressed here concern problems with health and live safety of staff and visitors alike, and also structural concerns that affect the long-term preservation of these important buildings.
42 ENGINEERING↗
Evolution of Structure and Magnetism in FeCl 2 and FeCl 3 : From Clusters to Monolayers
In this work, we address one of the most fundamental questions in cluster science─how do the structure and properties evolve from clusters to crystals? Using density functional theory (DFT), we focus our study on the evolution of structure and magnetism in iron-chloride systems, from clusters to monolayers. The choice of this system is motivated by the recent experimental confirmation of one of the author’s earlier theoretical prediction that the FeCl 2 cluster is magnetic with a spin magnetic moment of 4 μ B localized at the Fe site, while its dimer, Fe 2 Cl 4 , is antiferromagnetic. Similarly, FeCl 3 cluster is magnetic with a total spin magnetic moment of 5 μ B , with 4 μ B localized at the Fe site and 1 μ B distributed over the Cl sites. The dimer clusters Fe 2 Cl 4 and Fe 2 Cl 6 have an antiferromagnetic ground state, and upon Li-functionalization, both can be magnetically transformed from antiferromagnetic to ferromagnetic states. In contrast, FeCl 2 and FeCl 3 monolayers exhibit different magnetic ground states in their periodic forms: FeCl 2 is ferromagnetic (FM), but in FeCl 3 , the antiferromagnetic (AFM) and FM states are energetically nearly degenerate. Such a difference arises due to the different chemical coordination of the Fe atoms with the Cl atoms, caused by their different oxidation states, which is +2 in FeCl 2 and +3 in FeCl 3 , respectively. Interestingly, Li-functionalization allows both FeCl 3 and FeCl 2 monolayers to be ferromagnetic. Our study highlights that several, but not all, electronic and magnetic characteristics of isolated clusters are preserved in the extended periodic structures. This systematic investigation of iron-halide clusters is expected to inspire further experimental and theoretical exploration into the magnetism of other transition metal halides.
cluster chemistry↗
Beneficial Effects of La 0.5 Sr 0.5 CoO 3 Coatings on Thin‐Film LiMn 2 O 4 Cathodes for Lithium Ion Batteries
Abstract The severe capacity loss of spinel LiMn 2 O 4 (LMO) limits the utility of this otherwise promising lithium ion battery cathode material. One of the strategies to mitigate capacity fade is applying a coating on LMO particle surfaces. While this approach yields promising results, there is limited understanding of mechanisms whereby coatings improve LMO capacity retention. Herein, the effects of a new protective coating material, La 0.5 Sr 0.5 CoO 3 (LSCO), in a thin‐film battery geometry that is amenable to fundamental studies of electrode processes, are reported. RF sputtering deposition is used to produce high quality 25–100 nm LMO cathodes on Al 2 O 3 substrates with an intervening Pt/Ti back‐side contact layer. Cycling of the un‐coated cathodes results in capacity loss of 18% over 300 cycles. Adding a 2 nm LSCO layer reduces the capacity loss to 3%. While this may be due in part to reduced Mn dissolution, scanning transmission electron microscopy results indicate that the coating helps to preserve crystallinity and reduce lattice structure distortion due to inhibited formation of defect tetragonal spinel. Three‐electrode electrochemical impedance spectroscopy results reveal that the LSCO coating increases charge transfer and ohmic resistances, but the increases are generally too small to significantly impact cell performance even at high C‐rates.
25 ENERGY STORAGE↗
Effective biomass fractionation and lignin stabilization using a diol DES system
A sustainable and renewable biorefinery will increase the economic viability of lignocellulose-derived products. In this study, a diol-based deep eutectic solvent (DES) was developed to reduce the recalcitrance of bamboo, facilitate saccharification and valorize the lignin fraction. The DES pretreatment dramatically enhanced glucan digestibility by the effective removal of lignin (as high as 85.45%) and xylan (91.12%). Notably, the recovered lignin from DES pretreatment was protected during the fractionation, showing well-preserved β-O-4 structures (31.82%–59.06%). The mechanism of lignin protection was analyzed to be accomplished by incorporating the diol hydroxyl functional groups into the α position of the lignin β-O-4 structure via etherification. This work highlighted that diol DES is a promising pretreatment solvent to valorize both cellulose and lignin fractions with high enzymatic hydrolysis yield and high-quality lignin co-product.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Gas-solid reaction-based selective lithium leaching strategy for efficient LiFePO 4 recycling
As the electric-vehicle market continues to expand, LiFePO 4 (LFP) batteries, valued for their intrinsic safety and cost-effectiveness, are being increasingly utilized. However, this widespread adoption highlights the urgent need for innovative and environmentally friendly recycling methods for spent LFP batteries due to their relatively low material value and the environmental challenges associated with traditional recycling processes. Here, in this study, we present a novel selective lithium leaching technique that involves a gas–solid reaction with chlorine gas. This method achieves a remarkable leaching efficiency of 99.8 % and a selectivity of 98.8 % at 200 °C within just 10 min, without generating acidic wastewater. The resulting LiCl solution was successfully converted into Li 2 CO 3 with an excellent purity of 99.5 %, while producing NaCl solution as the only byproduct. Notably, the olivine structure of the LFP was preserved as FePO 4 after lithium leaching. The regenerated LFP demonstrated excellent performance, retaining 94.1 % of its capacity after 150 cycles, while the lithium-leached FePO 4 delivered a reversible capacity exceeding 150 mAh/g. This approach not only enhances the efficiency of LFP recycling but also paves the way for more sustainable battery technologies.
36 MATERIALS SCIENCE↗
Beyond Simple Dilution: Superior Conductivities from Cosolvation of Acetonitrile/LiTFSI Concentrated Solution with Acetone
Concentrated solutions of Li salts in acetonitrile are promising alternative electrolytes for the next generation of Li batteries as they may exhibit superior electrochemical properties. However, the reduced mobility of the chemical species is a barrier yet to be overcome, and for this, we explore the utilization of acetone as a cosolvent. Although acetone is a polar compound, we find that its addition to the LiTFSI/acetonitrile solution does not follow the trends expected for a simple dilution process. At a low concentration, acetone subtly shifts acetonitrile from the first to extended solvation sheaths of the ions. Still, most of the original structure of the solution is preserved, and mobile high-concentration clusters are formed in the solution. At higher concentrations, the cosolvation promotes cation–anion interactions but with a different nature from those in the original solution and still allows for a further increase in conductivity. Additionally, the non-coordinating fraction of acetonitrile acquires features resembling the pure solvent, which is a possible additional facilitating factor for ionic diffusion.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Single-Walled Zeolitic Nanotube–Poly(oxazoline) Nanocomposites as Heterogeneous Catalysts for Acid–Base Cascade Reactions
Zeolites with a unique, 1-dimensional form factor were recently discovered − zeolite nanotubes (ZNTs). Here we describe the synthesis and characterization of NaH-ZNTpoly( oxazoline) composites targeting liquid-phase acid−base cascade catalysis. NaH-ZNT, a one-dimensional zeolite analogue with mesoporosity (3−4 nm) associated with nanotubes and inherent Brønsted acid sites associated with the microporous zeolite domains, is functionalized with poly(oxazoline)-based triblock copolymers with varying molecular weights (3−17 kDa). The composites are characterized using N2 sorption, STEM, FTIR, and elemental analysis, confirming successful grafting and preservation of the zeolite nanotube structure. The composites’ catalytic performance is evaluated through separate acid and base reactions, followed by a combined cascade of a deacetalization−Knoevenagel condensation for the synthesis of chalcone compounds. High initial reaction rates are demonstrated, but modest overall cascade product formation rates are observed, attributed to interactions between Brønsted acid sites and base amine groups that occur in the polymer-grafted systems. Physical mixtures of NaH-ZNT-SH and poly(oxazoline)s, lacking covalent linkages between ZNT and the polymer, support this supposition. This work demonstrates the potential of NaH-ZNT-poly(oxazoline) composites for liquid-phase cascade catalysis for synthesizing compounds of potential medicinal interest, highlighting the benefits of the grafting-to approach as well as the need for further optimization of the catalytic performance.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Fabrication of Catalytic Distillation Membranes with Atomic Layer Deposition
The integration of catalysts onto the surface of membranes enables simultaneous physical separation and catalytic transformation of constituents in a feed stream, facilitating improved contaminant removal and fouling mitigation. Distillation membranes are a particularly attractive platform for catalytic membranes because they reject nonvolatile species and exhibit exceptional resistance to oxidative and radical-driven degradation. However, imparting catalytic functionality onto hydrophobic, porous distillation membranes has proven challenging since the membranes used are chemically inert and difficult to modify. Furthermore, catalysts on the membrane surface can decrease hydrophobicity and increase the membrane’s susceptibility to pore wetting and failure. In this work, we create a catalytic distillation membrane by coating a polytetrafluoroethylene membrane surface with titanium dioxide (TiO 2 ) via plasma-assisted atomic layer deposition (ALD). By precisely tuning the ALD parameters, we demonstrate localized growth of TiO 2 near (within approximately 1 μm) the surface of polytetrafluoroethylene membranes, forming a catalytically active interface while preserving the underlying hydrophobic pore structure. Localized growth of TiO 2 is confirmed by electron microscopy and spectroscopy techniques, and membranes coated with 500 cycles of ALD show pressure tolerance up to 12.8 bar and higher than 95% salt rejection in pressure-driven distillation. Photocatalytic activity is demonstrated via the degradation of methylene blue dye under UV irradiation, where increasing TiO2 loading leads to an enhancement in dye degradation. These results establish a general strategy for integrating catalytic functionality into chemically inert, hydrophobic membranes without compromising distillation performance, providing a pathway toward multifunctional membranes that couple advanced oxidation with membrane separation for water treatment.
atomic layer deposition↗
Surfactant Removal for Colloidal Nanocrystal Catalysts Mediated by N-Heterocyclic Carbenes
In this work, we report the facile removal of surfactants from col-loidally synthesized nanocrystals via a ligand ex-change with N-heterocyclic carbene (NHC). Subse-quent protonation of the NHC ligand in acid efficient-ly cleans the nanocrystal surface while preserving their uniform morphology and structure for catalysis. The broad efficacy of this strategy is validated using monodisperse Pt, Pd, and Au nanocrystals, each pre-pared with strongly bound phosphine stabilizers. The surface activated nanocrystals exhibit signifi-cantly improved catalytic activities, superior to other surface cleaning methods, as demonstrated in two centrally important electrochemical reactions (glyc-erol oxidation and CO 2 reduction). This work high-lights a new surface activation strategy for catalysis and other applications that enables the efficient use of well-defined nanocrystal libraries prepared by colloidal chemistry.
25 ENERGY STORAGE↗
Mineral Protection and Resource Limitations Combine to Explain Profile-Scale Soil Carbon Persistence
The fate of soil carbon (C) is largely controlled by microbial oxidation of organic matter (OM), which is constrained by a variety of mechanisms. OM association with soil minerals provides pronounced protection against microbial decomposition. However, factors such as climate, occlusion, and resource limitations also contribute to OM preservation. Here, we explore the factors explaining C distribution and age within an upland rainforest soil in Hawai'i, a site with abundant preferential flow paths (PFPs) and high short-range order (SRO) mineral content. We characterized lateral and vertical changes in Δ 14 C, SRO mineral content, C-functional group chemistry, and microbial community composition to elucidate the contributions of multiple protection mechanisms to OM preservation. Consistent with our expectation, SRO mineral content and Δ 14 C were strongly correlated (R 2 = 0.95), indicating strong mineral protection of OM throughout the profile. Surprisingly, distance from PFP was also a significant predictor of Δ 14 C and improved model fit, particularly in the shallow horizons (R 2 = 0.97). Elevated C/N ratios, decreased microbial abundance, and greater SRO mineral content suggest nitrogen limitations and enhanced mineral protection constrain OM turnover with distance from PFPs in deep, subsurface mineral horizons. Steady microbial abundance, increasing putative anaerobe abundance, and changes in C-functional group chemistry indicate oxygen limitations constrain OM turnover in the matrix of shallow mineral horizons. Given that oxygen and nutrient limitations contribute to OM preservation in this high SRO system—an exemplar of mineral protection—resource limitations may play an even more important role in OM preservation in other well-structured soils.
59 BASIC BIOLOGICAL SCIENCES↗
Selective designer hydrolysates from Miscanthus bioenergy crop for sustainable utilization
Designer enzymatic hydrolysates deliver targeted, optimized fermentable sugars while reducing the formation of inhibitory by-products. Herein, five distinct enzymatic hydrolysates (EH) were generated from Miscanthus biomass using alkaline-ethanol fractionation and hydrothermal-mechanical refining (HMR) pretreatment approaches. Noticeably, alkali-ethanol fractionated hemicellulose A (HMA) and hemicellulose B (HMB) hydrolysis resulted in xylose-rich enzymatic hydrolysates with 104.8 ± 5.6 g L −1 and 173.4 ± 4.6 g L −1 xylose, respectively. All five hydrolysates encompassing varied carbon to nitrogen ratios were evaluated for lipid production using an engineered oleaginous yeast, R. toruloides 880-ADS. Microbial fermentation of xylose-rich hydrolysates, viz. HMR-EH2, HMA-EH, and HMB-EH, resulted in lipid yields ranging from 0.05 to 0.12 g g −1 sugar. Compositional and 2D NMR analyses revealed that HMA-EH residues are highly lignin-enriched while preserving the non-condensed structure conducive to valorization. Overall, the findings highlighted a novel, selective trade-off approach for maximizing lipid titers from designer hydrolysates, corroborating complete resource recovery for establishing integrated biorefineries.
Singh, Shuchi [University of Illinois at Urbana-Ch↗
Raman studies of hydrogen trapped in As 4 O 6 ·2H 2 at high pressure and low temperature
In this work, Raman spectroscopic measurements of the arsenolite–hydrogen inclusion compound As 4 O 6 ·2H 2 were performed in diamond anvil cells at high pressure and variable temperature down to 80 K. The experimental results were complemented by ab initio molecular dynamics simulations and phonon calculations. Observation of three hydrogen vibrons in As 4 O 6 ·2H 2 is reported in the entire temperature and pressure range studied (up to 24 GPa). While the experiments performed with protium and deuterium at variable temperatures allowed for the assignment of two vibrons as Q 1 (1) and Q 1 (0) transitions of ortho and para spin isomers of hydrogen trapped in the inclusion compound, the origin of the third vibron could not be unequivocally established. Low-temperature spectra revealed that the lowest-frequency vibron is actually composed of two overlapping bands of A g and T 2g symmetries dominated by H 2 stretching modes as predicted by our previous density functional theory calculations. We observed low-frequency modes of As 4 O 6 ·2H 2 vibrations dominated by H 2 “librations,” which were missed in a previous study. A low-temperature fine structure was observed for the J = 0 → 2 and J = 1 → 3 manifolds of hydrogen trapped in As 4 O 6 ·2H 2 , indicating the lifting of degeneracy due to an anisotropic environment. A non-spherical distribution was captured by molecular dynamics simulations, which revealed that the trajectory of H 2 molecules is skewed along the crystallographic $\langle$111$\rangle$ direction. Last but not least, low-temperature synchrotron powder x-ray diffraction measurements on As 4 O 6 ·2H 2 revealed that the bulk structure of the compound is preserved down to 5 K at 1.6 GPa.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Symplectic machine learning model for fast simulation of space-charge effects
Symplectic simulation of space-charge effects is crucial for the design and operation of high-intensity particle accelerators. Traditional methods for simulating these effects are often computationally expensive, resulting in significant overhead. In this work, we introduce a generative model based on a U-Net architecture within a generative adversarial network framework to efficiently simulate space-charge effects. The model is trained to predict the transverse multiparticle space-charge Hamiltonian, which can be physically computed using a gridless spectral method. The one-step symplectic transverse transfer map for the particles is then obtained by differentiating the predicted Hamiltonian. Benchmarking results demonstrate that this generative model achieves an order of magnitude higher computational efficiency compared to the spectral method, providing a highly efficient alternative for simulating space-charge effects with a large number of particles. By maintaining symplecticity, the model effectively preserves the phase-space structure and mitigates nonphysical errors in long-term simulations. This model has been integrated into jutrack, a novel autodifferentiable accelerator modeling code developed in the julia programming language.
Beam code development & simulation techniques↗
Structural Impact of Grid-Forming Inverters on Power System Coherency
This paper addresses the following fundamental research question: how does the integration of grid-forming inverters (GFMs) replacing conventional synchronous generators (SGs) impact the slow coherent eigen-structure and the low frequency oscillatory behavior of future power systems? Due to time-scale separated dynamics, generator states inside a coherent area synchronize over a fast time-scale due to stronger coupling, while the areas themselves synchronize over a slower time scale. Our mathematical analysis shows that due to the large-scale integration of GFMs, the weighted Laplacian structure of the frequency dynamics is preserved, however, the entries of the Laplacian may be significantly modified based on the location and penetration levels of the GFMs. This can impact and potentially significantly alter the coherency structure of the system. We have validated our findings with numerical results using the IEEE 68-bus test system.
Mukherjee, Sayak [BATTELLE (PACIFIC NW LAB)]↗
Adhesive-Bonded Tab Attaches Thermocouples to Titanium
Mechanical strength of titanium-alloy structures that support thermocouples is preserved by first spotwelding thermocouples to titanium tabs and then attaching tabs to titanium with a thermosetting adhesive. In contrast to spot welding, a technique previously used for thermocouples, fatigue strength of the titanium is unaffected by adhesive bonding. Technique is also gentler than soldering or attaching thermocouples with a tap screw.
Cook, C. F.↗
Microbial mats and modern stromatolites in Shark Bay, Western Australia
Distribution, external morphology, texture, and microbial composition of microbial mats in Hamelin Pool, Shark Bay, Western Australia, have been studied and reviewed along a composite representative profile starting from the permanently submerged zone, across the zones of periodic flooding, toward permanently emerged land and coastal dunes. The following nine types of algal mats have been recognized: colloform, gelatinous, smooth, pincushion, tufted, mamillate, film, reticulate, and blister. Solar ponds represent a particular environment. The mat types represent microbial communities that are characterized by one or more dominant microorganisms. The colonization and stabilization of loose sediment is carried out by a microbial assemblage of generalists that prepare the ground for later replacement and succession by specialized microflora. Lithification of microbial mats takes place periodically, mainly during the austral summer. This process is destructive for the microbial community but increases the preservation potential of the stromatolitic structures.
Golubic, S.↗
Origin and evolution of Gneiss-Charnockite rocks of Dharmapuri District, Tamil Nadu, India
A low- to high-grade transition area in Dharmapuri district was investigated petrologically and geochemically. The investigation confirmed the presence of a continuous section through a former lower crust, with felsic charnockites predominating the lower part and felsic gneisses the upper part. The structure of original gneisses is preserved in charnockites and the latter show petrographic evidence for prograde metamorphism. The prograde metamorphism is of isochemical nature as revealed by the similarity of compositions of tonalitic gneisses and tonalitic charnockites. However, the depletion of LIL elements particularly Rb, caused variation in K/Rb ratios from low values (345) in the gneisses in upper part to higher values (1775) in the charnockites in the lower crust. This variation in K/Rb ratio in a north to south traverse is related to the progressive break-down of hydrous minerals under decreasing H2O and increasing CO2 fluid conditions. Metasomatism and partial melting has also taken place to a limited extent along shear planes and weak zones. During cooling the H2O circulation affected substantial auto-regression in the transition zone resulting in the formation of second generation biotite.
Rao, D. Rameshwar↗