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At least 1,729 records · Page 96
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Measurements of the Branching Fraction, Polarization, and C P Asymmetry for the Decay B 0 → ω ω

We present a comprehensive study of B 0 → ω ω decays using 772 × 10 6 B B ¯ pairs collected with the Belle detector at the KEKB e + e − collider. This process is a suppressed charmless decay into two vector mesons and can exhibit interesting polarization and C P violation. The decay is observed for the first time with a significance of 7.9 standard deviations. We measure a branching fraction B = ( 1.53 ± 0.29 ± 0.17 ) × 10 − 6 , a fraction of longitudinal polarization f L = 0.87 ± 0.13 ± 0.13 , and a time-integrated C P asymmetry A C P = − 0.44 ± 0.43 ± 0.11 , where the first uncertainties listed are statistical and the second are systematic. This is the first observation of B 0 → ω ω and the first measurements of f L and A C P for this decay. Published by the American Physical Society 2024

Physics↗
DOE OSTI2016

P and S wave responses of bacterial biopolymer formation in unconsolidated porous media

This study investigated the P and S wave responses and permeability reduction during bacterial biopolymer formation in unconsolidated porous media. Column experiments with fine sands, where the model bacteria Leuconostoc mesenteroides were stimulated to produce insoluble biopolymer, were conducted while monitoring changes in permeability and P and S wave responses. The bacterial biopolymer reduced the permeability by more than 1 order of magnitude, occupying ~10% pore volume after 38 days of growth. This substantial reduction was attributed to the bacterial biopolymer with complex internal structures accumulated at pore throats. S wave velocity (V S ) increased by more than ~50% during biopolymer accumulation; this indicated that the bacterial biopolymer caused a certain level of stiffening effect on shear modulus of the unconsolidated sediment matrix at low confining stress conditions. Whereas replacing pore water by insoluble biopolymer was observed to cause minimal changes in P wave velocity (VP) due to the low elastic moduli of insoluble biopolymer. The spectral ratio analyses revealed that the biopolymer formation caused a ~50-80% increase in P wave attenuation (1/Q P ) at the both ultrasonic and subultrasonic frequency ranges, at hundreds of kHz and tens of kHz, respectively, and a ~50-60% increase in S wave attenuation (1/Q S ) in the frequency band of several kHz. Our results reveal that in situ biopolymer formation and the resulting permeability reduction can be effectively monitored by using P and S wave attenuation in the ultrasonic and subultrasonic frequency ranges. Finally, this suggests that field monitoring using seismic logging techniques, including time-lapse dipole sonic logging, may be possible.

58 GEOSCIENCES↗
DOE OSTI2015

Controlled Anisotropic Growth of Co-Fe-P from Co-Fe-O Nanoparticles

Presented here is a facile approach to bimetallic phosphides, Co-Fe-P, via high-temperature (300°C) reaction between Co-Fe-O nanoparticles and trioctylphosphine. The growth of Co-Fe-P from the Co-Fe-O is anisotropic. As a result, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both nanorod and the sea-urchin-arm dimensions controlled by Co/Fe ratios. The Co-Fe-P structure, especially the sea-urchin-like (Co 0.54 Fe 0.46 ) 2 P, shows enhanced catalysis for oxygen evolution reaction in KOH with its catalytic efficiency surpassing Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A parallel p ‐adaptive discontinuous Galerkin method for the Euler equations with dynamic load‐balancing on tetrahedral grids

Abstract A novel p ‐adaptive discontinuous Galerkin (DG) method has been developed to solve the Euler equations on three‐dimensional tetrahedral grids. Hierarchical orthogonal basis functions are adopted for the DG spatial discretization while a third order TVD Runge‐Kutta method is used for the time integration. A vertex‐based limiter is applied to the numerical solution in order to eliminate oscillations in the high order method. An error indicator constructed from the solution of order and is used to adapt degrees of freedom in each computational element, which remarkably reduces the computational cost while still maintaining an accurate solution. The developed method is implemented with under the Charm++ parallel computing framework. Charm++ is a parallel computing framework that includes various load‐balancing strategies. Implementing the numerical solver under Charm++ system provides us with access to a suite of dynamic load balancing strategies. This can be efficiently used to alleviate the load imbalances created by p ‐adaptation. A number of numerical experiments are performed to demonstrate both the numerical accuracy and parallel performance of the developed p ‐adaptive DG method. It is observed that the unbalanced load distribution caused by the parallel p ‐adaptive DG method can be alleviated by the dynamic load balancing from Charm++ system. Due to this, high performance gain can be achieved. For the testcases studied in the current work, the parallel performance gain ranged from 1.5× to 3.7×. Therefore, the developed p ‐adaptive DG method can significantly reduce the total simulation time in comparison to the standard DG method without p ‐adaptation.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Large‐scale plant growth chamber design for elevated p CO 2 and δ 13 C studies

Rationale Throughout at least the next century, CO 2 fertilization and environmental stresses (e.g. nutrient, moisture, insect herbivory) are predicted to affect yields of economically important crop species. Stable isotopes of carbon are used to study plant stresses, which affect yields, but a growth chamber design that can be used to isolate the effects of environmental stresses on crop‐sized species through precise maintenance of p CO 2 levels and the δ 13 C values of atmospheric CO 2 (δ 13 C CO2 ) is lacking. Methods We designed and built low‐cost plant growth chambers for growing staple crop species under precise p CO 2 and δ 13 C CO2 conditions. Over the course of 14 hours, we assessed for p CO 2 stability at two targeted levels (ambient, ~400 ppm; and 2×, ~800 ppm) and measured the δ 13 C CO2 value within the two chambers using a stable isotope ratio mass spectrometer. We also compared the temperature and relative humidity conditions within the two growth chambers, and in the ambient, outside air. Results Across our experimental period, we achieved δ 13 C CO2 stability (ambient: –8.05 ± 0.17‰; elevated: –12.99 ± 0.29‰) that showed nearly half the variability of any previously reported values for other chamber designs. The stability of the p CO 2 conditions (ambient: 406 ± 3 ppm; elevated: 793 ± 54 ppm) was comparable with that in previous studies, but our design provided ~8 times more growing space than previous chamber designs. We also measured nearly identical temperature and relative humidity conditions for the two chambers throughout the experiment. Conclusions Our growth chamber design marks a significant improvement in our ability to test for plant stress across a range of future p CO 2 scenarios. Through significant improvement in δ 13 C CO2 stability and increased chamber size, small changes in carbon isotope fractionation can be used to assess stress in crop species under specific environmental (temperature, relative humidity, p CO 2 ) conditions. Copyright © 2015 John Wiley & Sons, Ltd.

Hagopian, William M.↗
DOE OSTI2016

GSE1 negative regulation by miR-489-5p promotes breast cancer cell proliferation and invasion

Gse1 coiled-coil protein (GSE1), also known as KIAA0182, is a proline rich protein. However, the function of GSE1 is largely unknown. In this study, we reported that GSE1 is overexpression in breast cancer and silencing of GSE1 significantly suppressed breast cancer cells proliferation, migration and invasion. Furthermore, GSE1 was identified as a direct target of miR-489-5p, which is significantly reduced in breast cancer tissues. In addition, forced expression of miR-489-5p suppressed breast cancer cells proliferation, migration and invasion. Moreover, depletion of GSE1 by siRNAs significantly abrogated the enhanced proliferation, migration and invasion of breast cancer cells consequent to miR-489-5p depletion. Taken together, these findings suggest that GSE1 may function as a novel oncogene in breast cancer and it can be regulated by miR-489-5p. - Highlights: • GSE1 is overexpressed in breast cancer and increased GSE1 expression predicts poor prognosis in breast cancer patients. • Knockdown of GSE1 inhibits breast cancer cell proliferation, migration and invasion. • GSE1 is a direct target of miR-489-5p. • Forced expression of miR-489-5p inhibits breast cancer cell proliferation, migration and invasion.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

MiR-628-5p decreases the tumorigenicity of epithelial ovarian cancer cells by targeting at FGFR2

Highlights: • miR-628-5p decreases the stem like cell percentage of epithelial ovarian cancer cells by inducing their apoptosis. • miR-628-5p decreases the tumourigenecity of epithelial ovarian cancer cells. • miR-628-5p targets at and down regulates the expression of fibroblast growth factor receptor 2. • Fibroblast growth factor receptor 2 expresses higher in ovarian cancer tissues and is correlated with worse prognosis. Micro RNAs (miRNAs) are small non-coding RNAs which are 19–24 nucleotides in length. MiRNAs play a vital role in the whole process of tumour development, but how they influence the tumourigenecity of epithelial ovarian cancer (EOC)cells is rarely researched. In our study, it was verified that miR-628-5p decreased the stem like cell percentage of EOC cells by inducing their apoptosis. The animal experiments showed that miR-628-5p decreased the tumourigenecity of EOC cells. Besides, we found miR-628-5p targeted at and down-regulated the expression of fibroblast growth factor receptor 2 (FGFR2). FGFR2 expressed higher in ovarian cancer tissues and was correlated with worse prognosis. Our findings indicated that miR-628-5pplays an important role in ovarian cancer stem cell driven tumorigenesis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

MiR-141-3p is upregulated in esophageal squamous cell carcinoma and targets pleckstrin homology domain leucine-rich repeat protein phosphatase-2, a negative regulator of the PI3K/AKT pathway

Highlights: • The PI3K/AKT pathway plays essential roles in their development and progression. • PHLPP2 is a negative regulator of the PI3K/AKT pathway. • MiRNAs are involved in cancer progression and metastasis. • MiR-141-3p expression is upregulated in esophageal squamous cell carcinoma cells. • MiR-141-3p targets PHLPP2 at its 3′-untranslated region. The phosphatidylinositol-3-kinase (PI3K)/AKT pathway is frequently activated in various human cancers and plays essential roles in their development and progression. Accumulating evidence suggests that dysregulated expression of microRNAs (miRNAs) is closely associated with cancer progression and metastasis. Here, we focused on miRNAs that could regulate genes related to the PI3K/AKT pathway in esophageal squamous cell carcinoma (ESCC). To identify upregulated miRNAs and their possible target genes in ESCC, we performed microarray-based integrative analyses of miRNA and mRNA expression levels in three human ESCC cell lines and a normal esophageal epithelial cell line. The miRNA microarray analysis revealed that miR-31-5p, miR-141-3p, miR-200b-3p, miR-200c-3p, and miR-205-5p were expressed at higher levels in the ESCC cell lines than the normal esophageal epithelial cell line. Bioinformatical analyses of mRNA microarray data identified several AKT/PI3K pathway-related genes as candidate targets of these miRNAs, which include tumor suppressors such as DNA-damage-inducible transcript 4 and pleckstrin homology domain leucine-rich repeat protein phosphatase-2 (PHLPP2). To validate the targets of relevant miRNAs experimentally, synthetic mimics of the miRNAs were transfected into the esophageal epithelial cell line. Here, we report that miR-141-3p suppress the expression of PHLPP2, a negative regulators of the AKT/PI3K pathway, as a target in ESCC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Li 7 P 3 S 11 electrolyte for all-solid-state lithium-ion batteries: structure, synthesis, and applications

Because of a high ion conductivity (10 -2 S cm -1 ) comparable with liquid electrolytes at room temperature, Li 7 P 3 S 11 , one of the most important solid state electrolytes (SSEs), has attracted significant attention for applications in all-solid-state lithium batteries (ASSLBs). The development of Li 7 P 3 S 11 has progressed impressively in recent years. A fundamental understanding of Li 7 P 3 S 11 SSE from its crystal structure and ion conductivity to practical applications is critical for the development of Li 7 P 3 S 11 SSE based ASSLBs. In light of that, this review presents an overview of the Li 7 P 3 S 11 SSE. Herein, the review addresses 1) the crystal structure and Li + diffusion mechanism; 2) developed synthesis methods and corresponding crystal growth mechanisms; 3) challenges and strategies of Li 7 P 3 S 11 SSE in practical applications. Finally, remaining challenges and future perspectives are highlighted.

25 ENERGY STORAGE↗
DOE OSTI2021

CO 2 electro-reduction on Cu 3 P: Role of Cu(I) oxidation state and surface facet structure in C 1 -formate production and H 2 selectivity

We report the catalytic activity and mechanism of copper(I) phosphide, Cu 3 P, with predominant [00Ι] facet exposure for the electrochemical reduction of CO 2 (CO 2 RR) to formic acid. Crystalline nanosheets of this compound that show a preferential [00Ι] facet orientation exhibit undiminished CO 2 RR activity after 16 hours with full retention of crystal structure and surface chemical speciation and no detectable corrosion. In contrast to the range of products formed on Cu metal, CuO, and Cu 2 O, the CO 2 RR on Cu 3 P [00Ι] produces mainly hydrogen and formate as the sole carbon product in KHCO 3 electrolyte. Analysis of the Cu 3 P [00Ι] facet by HAADF-STEM was used to determine the surface lattice structure, while both XPS and Auger spectroscopies were used to determine the surface chemical speciation from the kinetic energies of ionized electrons. The presented analysis identifies isolated trigonal CuP 3 sites on the Cu 3 P[00Ι]-Cu 3 P 3 terminated surface and the Cu(I) oxidation state as precursor to the active catalyst. The CO 2 RR selectivity to formate and the higher turnover rate for H 2 production on the [00Ι] facet allows a structure-activity analysis and chemical mechanism to be proposed. Formation of a surface hydride at isolated *H-CuP 3 sites is proposed as the catalytic site in forming both H 2 and formate, while the long Cu—Cu separation retards forming C-C coupling products. In conclusion, these results disprove previously published claims of Cu(I) oxidation state as a sufficient criterion to promote CO 2 RR to C 2+ products, show that stronger bonded hydrides, *H-CuP 3 on Cu 3 P, favor production of the C1 product formate over all other carbon products, and predict that stronger formate binding (bidentate) is needed for CO 2 RR currents to compete with H 2 production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Selenoprotein P Inhibits Radiation-Induced Late Reactive Oxygen Species Accumulation and Normal Cell Injury

Purpose: Radiation is a common mode of cancer therapy whose outcome is often limited because of normal tissue toxicity. We have shown previously that the accumulation of radiation-induced late reactive oxygen species (ROS) precedes cell death, suggesting that metabolic oxidative stress could regulate cellular radiation response. The purpose of this study was to investigate whether selenoprotein P (SEPP1), a major supplier of selenium to tissues and an antioxidant, regulates late ROS accumulation and toxicity in irradiated normal human fibroblasts (NHFs). Methods and Materials: Flow cytometry analysis of cell viability, cell cycle phase distribution, and dihydroethidium oxidation, along with clonogenic assays, were used to measure oxidative stress and toxicity. Human antioxidant mechanisms array and quantitative real-time polymerase chain reaction assays were used to measure gene expression during late ROS accumulation in irradiated NHFs. Sodium selenite addition and SEPP1 overexpression were used to determine the causality of SEPP1 regulating late ROS accumulation and toxicity in irradiated NHFs. Results: Irradiated NHFs showed late ROS accumulation (4.5-fold increase from control; P<.05) that occurs after activation of the cell cycle checkpoint pathways and precedes cell death. The mRNA levels of CuZn- and Mn-superoxide dismutase, catalase, peroxiredoxin 3, and thioredoxin reductase 1 increased approximately 2- to 3-fold, whereas mRNA levels of cold shock domain containing E1 and SEPP1 increased more than 6-fold (P<.05). The addition of sodium selenite before the radiation treatment suppressed toxicity (45%; P<.05). SEPP1 overexpression suppressed radiation-induced late ROS accumulation (35%; P<.05) and protected NHFs from radiation-induced toxicity (58%; P<.05). Conclusion: SEPP1 mitigates radiation-induced late ROS accumulation and normal cell injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

A comparative study of the atomic structures of Ge-doped As 4 S 3 and P 4 Se 3 molecular glasses

The structures of pseudo-binary P-Se and As-S glasses with compositions close to the P 4 Se 3 and As 4 S 3 stoichiometry with a few atom %Ge doping were determined using Monte Carlo simulations constrained by density and x-ray scattering measurements. We find that these glasses consist predominantly of P 4 Se 3 and As 4 S 3 molecules. The Ge doping results in some important differences between the two glasses. The P-Se glass displays significantly higher intermolecular connectivity via P-Se-Ge linkages, consistent with the significantly higher glass transition temperature and lower fragility of this liquid compared to its As-S counterpart. We also speculate that a consequence of this difference in the intermolecular connectivity would be to delay any pressure induced conversion from a molecular to a network structure for the Ge doped P-Se glass compared to the Ge-doped As-S glass.

36 MATERIALS SCIENCE↗
DOE OSTI2014

New high-pressure polymorph of In{sub 2}S{sub 3} with defect Th{sub 3}P{sub 4}-type structure

The high pressure behavior of β-In{sub 2}S{sub 3} (I4{sub 1}/amd and Z=16) has been studied by in situ synchrotron radiation X-ray diffraction combined with diamond anvil cell up to 71.7 GPa. Three pressure-induced phase transitions are evidenced at ∼6.6 GPa, ∼11.1 GPa at room temperature and 35.6 GPa after the high-temperature annealing using a portable laser heating system. The new polymorph of In{sub 2}S{sub 3} at 35.6 GPa is assigned to the denser cubic defect Th{sub 3}P{sub 4} structure (I4¯3d and Z=5.333), whose unit-cell parameters are a=7.557(1) Å and V=431.6(2) Å{sup 3}. The Th{sub 3}P{sub 4}-type phase can be stable at least up to 71.7 GPa and cannot be preserved at ambient pressure. The pressure–volume relationship is well described by the second-order Birch–Murnaghan Equation of State, which yields B{sub 0}=63(3) GPa and B{sub 0}′=4 (fixed) for the β-In{sub 2}S{sub 3} phase and B{sub 0}=87(3) GPa and B{sub 0}′=4 (fixed) for the defect Th{sub 3}P{sub 4}-type phase respectively. - Graphical abstract: The structure and Rietveld refinement of new polymorph the defect Th{sub 3}P{sub 4}-type In{sub 2}S{sub 3}. This structure was observed at 35.6 GPa after laser heating by X-ray diffraction. Display Omitted - Highlights: Three pressure-induced phase transitions of β-In{sub 2}S{sub 3} were observed. β-In{sub 2}S{sub 3} was stable up to 6.6 GPa. The defect Th{sub 3}P{sub 4}-type In{sub 2}S{sub 3} was identified at 35.6 GPa after laser heating and was stable up to 71.7 GPa. Elastic properties of β-In{sub 2}S{sub 3} and Th{sub 3}P{sub 4}-type In{sub 2}S{sub 3} are well presented by Birch–Murnaghan EoS.

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

Effect of p-type multi-walled carbon nanotubes for improving hydrogen storage behaviors

In this study, the hydrogen storage behaviors of p-type multi-walled carbon nanotubes (MWNTs) were investigated through the surface modification of MWNTs by immersing them in sulfuric acid (H{sub 2}SO{sub 4}) and hydrogen peroxide (H{sub 2}O{sub 2}) at various ratios. The presence of acceptor-functional groups on the p-type MWNT surfaces was confirmed by X-ray photoelectron spectroscopy. Measurement of the zeta-potential determined the surface charge transfer and dispersion of the p-type MWMTs, and the hydrogen storage capacity was evaluated at 77 K and 1 bar. From the results obtained, it was found that acceptor-functional groups were introduced onto the MWNT surfaces, and the dispersion of MWNTs could be improved depending on the acid-mixed treatment conditions. The hydrogen storage was increased by acid-mixed treatments of up to 0.36 wt% in the p-type MWNTs, compared with 0.18 wt% in the As-received MWNTs. Consequently, the hydrogen storage capacities were greatly influenced by the acceptor-functional groups of p-type MWNT surfaces, resulting in increased electron acceptor–donor interaction at the interfaces. - Graphical abstract: Hydrogen storage behaviors of the p-type MWNTs with the acid-mixed treatments are described. Display Omitted Display Omitted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

A chimeric protein composed of NuMA fused to the DNA binding domain of LANA is sufficient for the ori-P-dependent DNA replication

The Kaposi's sarcoma-associated herpesvirus (KSHV) genome is stably maintained in KSHV-infected PEL cell lines during cell division. We previously showed that accumulation of LANA in the nuclear matrix fraction could be important for the latent DNA replication, and that the functional significance of LANA should be its recruitment of ori-P to the nuclear matrix. Here, we investigated whether the forced localization of the LANA-DNA binding domain (DBD) to the nuclear matrix facilitated ori-P-containing plasmid replication. We demonstrated that chimeric proteins constructed by fusion of LANA DBD with the nuclear mitotic apparatus protein (NuMA), which is one of the components of the nuclear matrix, could bind with ori-P and enhance replication of an ori-P-containing plasmid, compared with that in the presence of DBD alone. These results further suggested that the ori-P recruitment to the nuclear matrix through the binding with DBD is important for latent viral DNA replication. - Highlights: •KSHV replication in latency depends on LANA localization to the nuclear matrix. •LANA DBD was fused with NuMA, a nuclear matrix protein, at the N- and C-terminus. •NuMA-DBD was in the nuclear matrix and supported the ori-P dependent replication. •LANA in the nuclear matrix should be important for the KSHV replication in latency.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

miR-31-5p promotes proliferation and inhibits apoptosis of goat hair follicle stem cells by targeting RASA1/MAP3K1 pathway

Highlights: • MAP3K1 was upregulated in hair follicle stem cells in response to overexpression miR-31–5p. • We confirmed RASA1 as a target gene of miR-31–5p. • Inhibition of miR-31–5p promotes apoptosis. • The miR-31–5p/RASA1/MAP3K1 axis regulates hair follicle stem cells activity via MAPK pathway. The Yangtze River Delta white goat is a sole goat species that can naturally produce superior-quality brush hair. It's worth to mention that study the developmental mechanism of goat hair follicle stem cells is vital for future breed preservation and molecular breeding. In this study, we successfully isolated hair follicle stem cells from the skin tissue of fetal sheep neck spine, and harvested superior-quality and normal-quality brush hair goat tissue. The expression of miR-31-5p in goat hair follicle stem cells was verified by qPCR and Western blot. The effects of overexpression or inhibition of miR-31-5p on the proliferation and apoptosis of hair follicle stem cells were detected by EdU, CCK-8, flow cytometry, etc. miR-31-5p can significantly improve cell proliferation and inhibit cell apoptosis by targeting RASA1 and upregulating MAP3K1 level, whereas miR-31-5p knockdown led to an opposite effect. These results reveal a miR-31-5p-associated regulatory network between miR-31-5p and RASA1/MAP3K1 during the progression of superiorquality brush hair traits.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Li 15 P 4 S 16 Cl 3 , a Lithium Chlorothiophosphate as a Solid-State Ionic Conductor

Tremendous efforts have been devoted to the design of solid Li + electrolytes and the development of all-solid-state batteries. Compared with conventional Li-ion batteries, which use flammable liquid organic electrolytes, all-solid-state batteries show significant advantages in safety. In this work, a novel lithium chlorothiophosphate compound, Li 15 P 4 S 16 Cl 3 , is discovered. The crystal structure and electrochemical properties are investigated. Li 15 P 4 S 16 Cl 3 can be synthesized as a pure phase via a facile solid-state reaction by heating a ball-milled mixture of Li 2 S, P 2 S 5 , and LiCl at 360 °C. The crystal structure of Li 15 P 4 S 16 Cl 3 was refined against neutron and synchrotron powder X-ray diffraction data, revealing that it crystallizes in the space group $I\bar{4}3d$. Furthermore, the Li + transport in Li 15 P 4 S 16 Cl 3 was also investigated by multiple solid-state NMR methods, including variable-temperature NMR line-shape analysis, NMR relaxometry, and pulsed-field-gradient NMR. Li 15 P 4 S 16 Cl 3 shows good thermodynamic stability and can be synthesized at relatively low temperature. Although it exhibits a low ionic conductivity at room temperature, it can serve as a new motif crystal structure for the design and development of new solid-state electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2017

Origin of Outstanding Phase and Moisture Stability in a Na 3 P 1– x As x S 4 Superionic Conductor

Sodium ion (Na) solid-state electrolytes (SSEs) are critical to address notorious safety issues associated with liquid electrolytes used in the current Na ion batteries. Fulfilling multiple innovations is a grand challenge but is imperative for advanced Na ion SSEs, such as a combination of high ionic conductivity and excellent chemical stability. Here, our first-principles and phonon calculations reveal that Na 3 P 1–x As x S 4 (0 ≤ x ≤ 1) is a solid-state superionic conductor stabilized at 0 K by zero-point vibrational energy and at finite temperatures by vibrational and configurational entropies. Especially, our integrated first-principles and experimental approach indicates that Na 3 P 1–x As x S 4 is dry-air stable. Additionally, the alloying element arsenic greatly enhances the moisture (i.e., H 2 O) stability of Na 3 P 1–x As x S 4 by shifting the reaction products from the easy-forming oxysulfides (such as Na 3 POS 3 and Na 3 PO 2 S 2 with H 2 S release) to the difficult-forming hydrates (such as Na 3 P 1–x As x S 4 ·$n$H 2 O with n = 8 and/or 9) due mainly to a weaker As–O affinity compared to that of P–O. The present work demonstrates that alloying is able to achieve multiple innovations for solid-state electrolytes, such as a desirable superionic conductor with not only a high ionic conductivity (for example, 1.46 mS/cm at room temperature achieved in Na 3 P 0.62 As 0.38 S 4 ) but also an excellent chemical stability with respect to temperature, composition, and moisture.

36 MATERIALS SCIENCE↗