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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Multifunctional Fibroblasts Enhanced via Thermal and Freeze-Drying Post-treatments of Aligned Electrospun Nanofiber Membranes

Parallel fibrous scaffolds play a critical role in controlling the morphology of cells to be more natural and biologically inspired. Among popular tissue engineering materials, poly(2-hydroxyethyl methacrylate) (pHEMA) has been widely investigated in conventional forms due to its biocompatibility, low toxicity, and hydrophilicity. However, the swelling of pHEMA in water remains a major concern. To address this issue, randomly oriented and aligned as-spun pHEMA nanofibrous scaffolds were first fabricated at speeds of 300 and 2000 rpm in this study, which were then post-treated using either a thermal or a freeze-drying method. In cell assays, human dermal fibroblasts (HDFs) adhered to the freeze-drying treated substrates at a significantly faster rate, whereas they had a higher cell growth rate on thermally-treated substrates. Results indicated that the structural properties of pHEMA nanofibrous scaffolds and subsequent cellular behaviors were largely dependent on post-treatment methods. Moreover, this study suggests that aligned pHEMA nanofibrous substrates tended to induce regular fibroblast orientation and unidirectionally oriented actin cytoskeletons over random pHEMA nanofibrous substrates. Such information has predictive power and provides insights into promising post-treatment methods for improving the properties of aligned pHEMA scaffolds for numerous tissue engineering applications.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Facile and low cost oxidative conversion of MoS{sub 2} in α-MoO{sub 3}: Synthesis, characterization and application

This study describes a facile low cost route to synthesize the α-MoO{sub 3} through a conversion of the precursor MoS{sub 2} in oxidant media. The structure and morphology of the α-MoO{sub 3} were studied by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results show that α-MoO{sub 3} was obtained with reduced size, high purity, strongly-preferred orientation and structural defects, which ensures versatility and multifunctionality to this sample. For the purpose of applications, α-MoO{sub 3} was successfully employed in inverted organic solar cells devices as a possible alternative to the PEDOT:PSS in the hole transportation layer. - Graphical abstract: Synthesis process based on low cost oxidative conversion of MoS{sub 2} in α-MoO{sub 3} Display Omitted - Highlights: • A facile route to obtain α-MoO{sub 3} by refluxing the MoS{sub 2} precursor in oxidant media. • High purity and strongly-preferred orientation. • Belt-shaped material. • Enhanced conversion efficiency (PCE) when compared with conventional PEDOT:PSS.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Synthesis of superparamagnetic silica-coated magnetite nanoparticles for biomedical applications

Multifunctional superparamagnetic iron oxide nanoparticles (SPIONs) coated with silica are widely researched for biomedical applications such as magnetic resonance imaging, tissue repair, cell separation, hyperthermia, drug delivery, etc. In this article synthesis of magnetite (Fe{sub 3}O{sub 4}) nanoparticles and their coating with SiO{sub 2} is reported. Fe{sub 3}O{sub 4} nanoparticles were synthesized by chemical co-precipitation and it was coated with silica by hydrolysis and condensation of tetraethylorthosilicate. XRD, FTIR, TEM and VSM techniques were used to characterize bare and coated nanoparticles. Results indicated that the average size of SPIONS was 8.4 nm. X-ray diffraction patterns of silica coated SPIONS were identical to that of SPIONS confirming the inner spinal structure of SPIONS. FTIR results confirmed the binding of silica with the magnetite and the formation of the silica shell around the magnetite core. Magnetic properties of SPIONS and silica coated SPIONS are determined by VSM. They are superparamagnetic. The major conclusion drawn from this study is that the synthesis route yields stable, non-aggregated magnetite-silica core-shell nanostructures with tailored morphology and excellent magnetic properties.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
NASA NTRS2019

Hypervelocity Impact Performance of 3D Printed Aluminum Panels

With the continued development of additive manufacturing methods, control over the shape of ligaments, cell regularity, and macroscopic shape can all be easily tuned. This capability allows for tailoring of component architecture and promotes potential mass savings in a space vehicle structure. Additionally, it allows one the flexibility of combining structural elements such as MMOD protection and vehicle stiffness for launch loads for an overall mass reduction. At NASA JSC this technology is being explored in many different ways with the goal being a multifunctional structural component. For this study, four different types of aluminum panels have been 3D printed for testing, three being of a body centric cubic (BCC) lattice structure core and one being kelvin cell structure core. All samples have a 5.33 cm (0.05”) nominally thick aluminum face sheet printed on the front and back side of each panel, with all core materials having a 5.08 cm (2.0”) nominal thickness (see Table 1 for test sample summary and Figures 1 – 2 for sample illustrations). These tests will evaluate the performance of 3D printed aluminum panels under hypervelocity impact (HVI) conditions. The hypervelocity impact tests are being conducted at the JSC White Sands Test Facility (WSTF) Remote Hypervelocity Test Laboratory (RHTL), located in Las Cruces, New Mexico. All tests will be conducted with a 3.4mm Al 2017-T4 sphere at 6.8 km/s impacting at 0° to surface normal (i.e., impacting with no obliquity). Each sample will be trapped between two metal frames, with gasket material residing between the sample and frame, which will be the shipping and testing configuration for all tests. There will be an Al 2017-T4 witness plate staged 5.08 cm (2.0”) from each sample to capture signature of debris, if the rear face sheet of the sample were to perforate from the HVI test event.

Davis, B. A.↗
DOE OSTI2016

Novel Structure and Unexpected RNA-Binding Ability of the C-Terminal Domain of Herpes Simplex Virus 1 Tegument Protein UL21

Proteins forming the tegument layers of herpesviral virions mediate many essential processes in the viral replication cycle, yet few have been characterized in detail. UL21 is one such multifunctional tegument protein and is conserved among alphaherpesviruses. While UL21 has been implicated in many processes in viral replication, ranging from nuclear egress to virion morphogenesis to cell-cell spread, its precise roles remain unclear. Here we report the 2.7-Å crystal structure of the C-terminal domain of herpes simplex virus 1 (HSV-1) UL21 (UL21C), which has a unique α-helical fold resembling a dragonfly. Analysis of evolutionary conservation patterns and surface electrostatics pinpointed four regions of potential functional importance on the surface of UL21C to be pursued by mutagenesis. In combination with the previously determined structure of the N-terminal domain of UL21, the structure of UL21C provides a 3-dimensional framework for targeted exploration of the multiple roles of UL21 in the replication and pathogenesis of alphaherpesviruses. Additionally, we describe an unanticipated ability of UL21 to bind RNA, which may hint at a yet unexplored function. IMPORTANCE Due to the limited genomic coding capacity of viruses, viral proteins are often multifunctional, which makes them attractive antiviral targets. Such multifunctionality, however, complicates their study, which often involves constructing and characterizing null mutant viruses. Systematic exploration of these multifunctional proteins requires detailed road maps in the form of 3-dimensional structures. In this work, we determined the crystal structure of the C-terminal domain of UL21, a multifunctional tegument protein that is conserved among alphaherpesviruses. Structural analysis pinpointed surface areas of potential functional importance that provide a starting point for mutagenesis. In addition, the unexpected RNA-binding ability of UL21 may expand its functional repertoire. The structure of UL21C and the observation of its RNA-binding ability are the latest additions to the navigational chart that can guide the exploration of the multiple functions of UL21.

Metrick, Claire M.↗
DOE OSTI2012

Multifunctional Solar Energy Systems Research Project

The solar energy available within the visible portion of the solar spectrum is about 300 W/m 2 (43%) and that available in the UV and IR portion is about 400 W/m 2 (57%). This provides opportunities for developing integrated energy systems that capture and use specific wavelengths of the solar spectrum for different purposes. For example: biofuels from photosynthetic microbes use only the visible light; solar cells use a narrow band of the solar spectrum that could be either mostly in the visible or in the IR regions of the solar spectrum, depending on the photovoltaic materials, e.g., gallium antimonide (GaSb) cells utilize predominately IR radiation; and finally, solar panels that heat water utilize a broad range of wavelengths (visible plus IR). The basic idea of this research is that sunlight has many possible end-use applications including both direct use and energy conversion schemes; it is technically feasible to develop multifunctional solar energy systems capable of addressing several end-use needs while increasing the overall solar energy utilization efficiency when compared to single-purpose solar technologies. Such a combination of technologies could lead to more cost-competitive "multifunctional" systems that add value and broaden opportunities for integrated energy systems. The goal of this research is to increase the overall energy efficacy and cost competitiveness of solar systems. The specific objectives of this research were: 1) Evaluate the efficacy of a combined photobioreactor and electric power system; 2) Improve the reliability and cost effectiveness of hybrid solar lighting systems – a technology in which sunlight is collected and distributed via optical fibers into the interior of a building; 3) Evaluate the efficacy of using filtered light to increase the production of biomass in photobioreactors and provide more solar energy for other uses; 4) Evaluates several concepts for wavelength shifting such that a greater percentage of the solar spectrum energy can be used for photosynthesis.

09 BIOMASS FUELS↗
DOE OSTI2018

Vertical Co 9 S 8 hollow nanowall arrays grown on a Celgard separator as a multifunctional polysulfide barrier for high-performance Li–S batteries

Lithium–sulfur (Li–S) batteries have been regarded as one of the most promising next-generation energy-storage devices, due to their low cost and high theoretical energy density (2600 W h kg -1 ). However, the severe dissolution of lithium polysulfides (LiPSs) and the fatal shuttle effect of the sulfur cathode seriously hinder the practical applications of Li–S batteries. To address such issues, we present here, for the first time, a novel metal organic framework (MOF)-derived Co 9 S 8 nanowall array with vertical hollow nanoarchitecture and high electrical conductivity, which is grown in situ on a Celgard separator (Co 9 S 8 –Celgard) via a feasible and scalable liquid-reaction approach, as an efficient barrier for LiPSs in Li–S batteries. Benefiting from the direct in situ growth of vertical Co 9 S 8 hollow nanowall arrays as a multifunctional polar barrier, the Co 9 S 8 –Celgard separator possesses large surface area, excellent mechanical stability, and particularly strong LiPS-trapping ability via chemical and physical interactions. With these advantages, even with a pure sulfur cathode with a high sulfur loading of 5.6 mg cm -2 , the Li–S cells with the Co 9 S 8 –Celgard separator exhibit outstanding electrochemical performance: the initial specific capacity is as high as 1385 mA h g -1 with a retention of 1190 mA h g -1 after 200 cycles. The cells deliver a high capacity of 530 mA h g -1 at a 1C rate (1675 mA g -1 ) even after an impressive number of 1000 cycles with an average capacity fade of only 0.039% per cycle, which is promising for long-term cycling application at high charge/discharge current densities, and pouch-type Li–S cells with the Co 9 S 8 –Celgard separator display excellent cycling performance. When the optimized cathode with the sulfur loading in well-designed yolk–shelled carbon@Fe 3 O 4 (YSC@Fe 3 O 4 ) nanoboxes is employed, the cell with Co 9 S 8 –Celgard delivers a high initial capacity of 986 mA h g -1 at a 1C rate with a capacity retention as high as 83.2% even after a remarkable number of 1500 cycles. In conclusion, this work presents a strategy to grow on the separator a multifunctional polar interlayer with unique nanoarchitecture and high conductivity to chemically and physically trap the LiPSs, thus significantly enhancing the performance of Li–S batteries.

25 ENERGY STORAGE↗
NASA NTRS2006

NASA Tech Briefs, September 2006

Topics covered include: Improving Thermomechanical Properties of SiC/SiC Composites; Aerogel/Particle Composites for Thermoelectric Devices; Patches for Repairing Ceramics and Ceramic- Matrix Composites; Lower-Conductivity Ceramic Materials for Thermal-Barrier Coatings; An Alternative for Emergency Preemption of Traffic Lights; Vehicle Transponder for Preemption of Traffic Lights; Automated Announcements of Approaching Emergency Vehicles; Intersection Monitor for Traffic-Light-Preemption System; Full-Duplex Digital Communication on a Single Laser Beam; Stabilizing Microwave Frequency of a Photonic Oscillator; Microwave Oscillators Based on Nonlinear WGM Resonators; Pointing Reference Scheme for Free-Space Optical Communications Systems; High-Level Performance Modeling of SAR Systems; Spectral Analysis Tool 6.2 for Windows; Multi-Platform Avionics Simulator; Silicon-Based Optical Modulator with Ferroelectric Layer; Multiplexing Transducers Based on Tunnel-Diode Oscillators; Scheduling with Automated Resolution of Conflicts; Symbolic Constraint Maintenance Grid; Discerning Trends in Performance Across Multiple Events; Magnetic Field Solver; Computing for Aiming a Spaceborne Bistatic- Radar Transmitter; 4-Vinyl-1,3-Dioxolane-2-One as an Additive for Li-Ion Cells; Probabilistic Prediction of Lifetimes of Ceramic Parts; STRANAL-PMC Version 2.0; Micromechanics and Piezo Enhancements of HyperSizer; Single-Phase Rare-Earth Oxide/Aluminum Oxide Glasses; Tilt/Tip/Piston Manipulator with Base-Mounted Actuators; Measurement of Model Noise in a Hard-Wall Wind Tunnel; Loci-STREAM Version 0.9; The Synergistic Engineering Environment; Reconfigurable Software for Controlling Formation Flying; More About the Tetrahedral Unstructured Software System; Computing Flows Using Chimera and Unstructured Grids; Avoiding Obstructions in Aiming a High-Gain Antenna; Analyzing Aeroelastic Stability of a Tilt-Rotor Aircraft; Tracking Positions and Attitudes of Mars Rovers; Stochastic Evolutionary Algorithms for Planning Robot Paths; Compressible Flow Toolbox; Rapid Aeroelastic Analysis of Blade Flutter in Turbomachines; General Flow-Solver Code for Turbomachinery Applications; Code for Multiblock CFD and Heat-Transfer Computations; Rotating-Pump Design Code; Covering a Crucible with Metal Containing Channels; Repairing Fractured Bones by Use of Bioabsorbable Composites; Kalman Filter for Calibrating a Telescope Focal Plane; Electronic Absolute Cartesian Autocollimator; Fiber-Optic Gratings for Lidar Measurements of Water Vapor; Simulating Responses of Gravitational-Wave Instrumentation; SOFTC: A Software Correlator for VLBI; Progress in Computational Simulation of Earthquakes; Database of Properties of Meteors; Computing Spacecraft Solar-Cell Damage by Charged Particles; Thermal Model of a Current-Carrying Wire in a Vacuum; Program for Analyzing Flows in a Complex Network; Program Predicts Performance of Optical Parametric Oscillators; Processing TES Level-1B Data; Automated Camera Calibration; Tracking the Martian CO2 Polar Ice Caps in Infrared Images; Processing TES Level-2 Data; SmaggIce Version 1.8; Solving the Swath Segment Selection Problem; The Spatial Standard Observer; Less-Complex Method of Classifying MPSK; Improvement in Recursive Hierarchical Segmentation of Data; Using Heaps in Recursive Hierarchical Segmentation of Data; Tool for Statistical Analysis and Display of Landing Sites; Automated Assignment of Proposals to Reviewers; Array-Pattern-Match Compiler for Opportunistic Data Analysis; Pre-Processor for Compression of Multispectral Image Data; Compressing Image Data While Limiting the Effects of Data Losses; Flight Operations Analysis Tool; Improvement in Visual Target Tracking for a Mobile Robot; Software for Simulating Air Traffic; Automated Vectorization of Decision-Based Algorithms; Grayscale Optical Correlator Workbench; "One-Stop Shopping" for Ocean Remote-Sensing and Model Data; State Analysis Database Tool; Generating CAHV and CAHVOmages with Shadows in ROAMS; Improving UDP/IP Transmission Without Increasing Congestion; FORTRAN Versions of Reformulated HFGMC Codes; Program for Editing Spacecraft Command Sequences; Flight-Tested Prototype of BEAM Software; Mission Scenario Development Workbench; Marsviewer; Tool for Analysis and Reduction of Scientific Data; ASPEN Version 3.0; Secure Display of Space-Exploration Images; Digital Front End for Wide-Band VLBI Science Receiver; Multifunctional Tanks for Spacecraft; Lightweight, Segmented, Mostly Silicon Telescope Mirror; Assistant for Analyzing Tropical-Rain-Mapping Radar Data; and Anion-Intercalating Cathodes for High-Energy- Density Cells.

Source record↗
DOE OSTI2020

Anomalously high elastic modulus of a poly(ethylene oxide)-based composite electrolyte

The practical use of lithium metal anodes in solid-state batteries requires a polymer membrane with high lithium-ion conductivity, thermal/electrochemical stability, and mechanical strength. The primary challenge is to effectively decouple the ionic conductivity and mechanical strength of the polymer electrolytes. We report a remarkably facile single step synthetic strategy based on in-situ crosslinking of poly(ethylene oxide) (xPEO) in the presence of a woven glass fiber (GF). Such a simple method yields composite polymer electrolytes (CPE) of anomalously high elastic modulus up to 2.5 GPa over a broad temperature range (20 °C – 245 °C) that has never been previously documented. An unsupervised machine learning algorithm, K-mean clustering analysis, was implemented on the hyperspectral Raman mapping at the xPEO/GF interface. Using such a unique means, we show for the first time that the promoted mechanical strength originates from xPEO and GF interactions through dynamic hydrogen and ionic bonding. High ionic conductivity is achieved by the addition plasticizer (e.g. tetraglyme), where trifluoromethanesulfonate anions are tethered to the xPEO matrix and Li + cations are favorably transported through coordination with the plasticizer. Further, stringent galvanostatic cycling tests indicates the CPE can be stably cycled for >3000 h in a Li-metal symmetric cell at a moderate temperature (nearly 1500 Coulombs/cm 2 Li equivalents), outperforming most of the PEO-based electrolytes. The GF reinforced CPE reported here has multifunctional uses, such as solid electrolytes for all solid-state batteries and membranes for redox-flow batteries. Although the focus of this study is on lithium-based batteries, the results are equally promising for other alkali metal based batteries such as sodium and potassium.

25 ENERGY STORAGE↗
DOE OSTI2020

Functionalized separator for next-generation batteries

Advancements in battery technology have dramatically increased demand for improvements in separator design, as the separator plays a critical role in ensuring the safety and electrochemical performance of the cells. Current separators, either in commercial usage or under investigation, have yet to meet the high stability and lifespan performance standards necessary to prevent deterioration in the efficiency and reliability of the battery technologies. Recently, considerable effort has been devoted to developing functionalized separators, ranging from designing a variety of new materials and modification methods, and increasingly, to optimizing advanced preparation processes. In order to understand how the mechanisms of separator performance are affected by different properties, we will first summarize recent research progress and then have in-depth discussions regarding the separator's significant contribution to enhancing the safety and performance of the cell. Additionally, we then provide our design strategy for future separators, which not only meets the requirements of different type of batteries, but also aims for multifunctionality. We hope such a perspective could provide new inspiration in the development of separator research for future battery technologies.

25 ENERGY STORAGE↗
NASA NTRS1992

Cell volume control at a surface for three-dimensional grid generation packages

An alternate method of calculating the cell size for orthogonality control in the solution of Poisson's 3D space equations is presented. The method provides the capability to enforce a better initial guess for the grid distribution required for boundary layer resolution. This grid point distribution is accomplished by enforcing grid spacing from a grid block boundary where orthogonality is required. The actual grid spacing or cell size for that boundary is determined by the two or four adjacent boundaries in the grid block definition, which are two dimensional grids. These two dimensional grids are in turn defined by the user using insight into the flow field and boundary layer characteristics. The adjoining boundaries are extended using a multifunctional blending scheme, with user control of the blending and interpolating functions to be used. This grid generation procedure results in an enhanced computational fluid dynamics calculation by allowing a quicker resolution of the configuration's boundary layer and flow field and by limiting the number of grid re-adaptations. The cell size specification calculation was applied to a variety of configurations ranging from axisymmetric to complex three-dimensional configurations. Representative grids are shown for the Space Shuttle and the Langley Lifting Body (HL-20).

Alter, Stephen J.↗
DOE OSTI2022

A systematic approach to resolve high impedance of multifunctional energy storage composites

Previous work has proposed and characterized the structural and electrical performance of Multifunctional Energy Storage Composite (MESC) structures: structural elements with embedded lithium-ion batteries which were developed by the Structures and Composite Laboratory (SACL) at Stanford University. This work conducts a comprehensive parametric study over the design variables in the manufacturing process to determine the root cause of increased DC impedance compared to commercial pouch cell batteries. Several MESC samples were assembled under various controlled environmental temperatures and pressures. The samples underwent Hybrid Peak Pulse Characterization (HPPC) to approximate the DC impedance as a function of state of charge (SOC). Failure limits of the battery with respect to assembly temperature and pressure were tested, and an MESC manufacturing simulation model was constructed in Abaqus to validate the manufacturing limits. Samples assembled without enough temperature or pressure failed due to a lack of structural integrity or hermetic seal. Conversely, samples which underwent elevated temperatures and pressures resulted in high DC impedance due to nonuniform electrolyte wetting. This work resolves the primary concern of MESC by achieving comparable DC impedance to commercial pouch cells of the same chemistry and testing procedure.

25 ENERGY STORAGE↗
DOE OSTI2015

Long-range, low-cost electric vehicles enabled by robust energy storage

ABSTRACT A variety of inherently robust energy storage technologies hold the promise to increase the range and decrease the cost of electric vehicles (EVs). These technologies help diversify approaches to EV energy storage, complementing current focus on high specific energy lithium-ion batteries. The need for emission-free transportation and a decrease in reliance on imported oil has prompted the development of EVs. To reach mass adoption, a significant reduction in cost and an increase in range are needed. Using the cost per mile of range as the metric, we analyzed the various factors that contribute to the cost and weight of EV energy storage systems. Our analysis points to two primary approaches for minimizing cost. The first approach, of developing redox couples that offer higher specific energy than state-of-the-art lithium-ion batteries, dominates current research effort, and its challenges and potentials are briefly discussed. The second approach represents a new insight into the EV research landscape. Chemistries and architectures that are inherently more robust reduce the need for system protection and enables opportunities of using energy storage systems to simultaneously serve vehicle structural functions. This approach thus enables the use of low cost, lower specific energy chemistries without increasing vehicle weight. Examples of such systems include aqueous batteries, flow cells, and all solid-state batteries. Research progress in these technical areas is briefly reviewed. Potential research directions that can enable low-cost EVs using multifunctional energy storage technologies are described.

36 MATERIALS SCIENCE↗
NASA NTRS2003

Laboratory and In-Flight In-Situ X-ray Imaging and Scattering Facility for Materials, Biotechnology and Life Sciences

We propose a multifunctional X-ray facility for the Materials, Biotechnology and Life Sciences Programs to visualize formation and behavior dynamics of materials, biomaterials, and living organisms, tissues and cells. The facility will combine X-ray topography, phase micro-imaging and scattering capabilities with sample units installed on the goniometer. This should allow, for the first time, to monitor under well defined conditions, in situ, in real time: creation of imperfections during growth of semiconductors, metal, dielectric and biomacromolecular crystals and films, high-precision diffraction from crystals within a wide range of temperatures and vapor, melt, solution conditions, internal morphology and changes in living organisms, tissues and cells, diffraction on biominerals, nanotubes and particles, radiation damage, also under controlled formation/life conditions. The system will include an ultrabright X-ray source, X-ray mirror, monochromator, image-recording unit, detectors, and multipurpose diffractometer that fully accommodate and integrate furnaces and samples with other experimental environments. The easily adjustable laboratory and flight versions will allow monitoring processes under terrestrial and microgravity conditions. The flight version can be made available using a microsource combined with multilayer or capillary optics.

Source record↗
DOE OSTI2020

Digital alloy contact layers for perovskite solar cells

Thin film optoelectronic devices commonly require an individual material to perform multiple functions, but the physical properties of single-composition materials often cannot be tuned to optimize these diverse requirements. The electron selective contact layer in perovskite solar cells is a prime example. The material must simultaneously have optimal conduction band alignment, facilitate carrier extraction, prevent recombination, and provide a chemically stable interface with the notoriously volatile perovskite semiconductor. The pulse-by-pulse nature of the thin-film deposition method pulsed laser deposition (PLD) provides an opportunity to form material alloys where the chemical composition is controlled at the nanometer scale. These digital alloys may prove to be a powerful materials class to meet some of the multifunctional needs of thin film devices. Using PLD to make electron transport layers from ZnO and MgZnO targets, we demonstrate in this paper that digital alloy gradients can be tuned to significantly outperform either of the parent materials in perovskite solar cells.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Building Organic/Inorganic Hybrid Interphases for Fast Interfacial Transport in Rechargeable Metal Batteries

Abstract We report a facile in situ synthesis that utilizes readily accessible SiCl 4 cross‐linking chemistry to create durable hybrid solid–electrolyte interphases (SEIs) on metal anodes. Such hybrid SEIs composed of Si‐interlinked OOCOR molecules that host LiCl salt exhibit fast charge‐transfer kinetics and as much as five‐times higher exchange current densities, in comparison to their spontaneously formed analogues. Electrochemical analysis and direct optical visualization of Li and Na deposition in symmetric Li/Li and Na/Na cells show that the hybrid SEI provides excellent morphological control at high current densities (3–5 mA cm −2 ) for Li and even for notoriously unstable Na metal anodes. The fast interfacial transport attributes of the SEI are also found to be beneficial for Li‐S cells and stable electrochemical cycling was achieved in galvanostatic studies at rates as high as 2 C. Our work therefore provides a promising approach towards rational design of multifunctional, elastic SEIs that overcome the most serious limitations of spontaneously formed interphases on high‐capacity metal anodes.

Zhao, Qing↗
DOE OSTI2018

Catalase inhibition induces pexophagy through ROS accumulation

Highlights: • Catalase deficiency or its inhibition by 3 A T during serum starvation results in pexophagy. • Pexophagy mediated by catalase inhibition is accompanied by PEX5 ubiquitination. • ROS accumulation in peroxisome is the key factor to induce pexophagy. • N-acetyl-l-cysteine prevents ROS-mediated pexophagy. Peroxisomes are dynamic and multifunctional organelles involved in various cellular metabolic processes, and their numbers are tightly regulated by pexophagy, a selective degradation of peroxisomes through autophagy to maintain peroxisome homeostasis in cells. Catalase, a major peroxisome protein, plays a critical role in removing peroxisome-generated reactive oxygen species (ROS) produced by peroxisome enzymes, but the contribution of catalase to pexophagy has not been reported. Here, we investigated the role of catalase in peroxisome degradation during nutrient deprivation. Both short interfering RNA-mediated silencing of catalase and pharmacological inhibition by 3-aminotriazole (3AT) decreased the number of peroxisomes and resulted in the downregulation of peroxisomal proteins, such as PMP70 and PEX14 under serum starvation. In addition, treatment with 3AT induced NBR1-dependent autophagy and PEX5 ubiquitination in the absence of serum, which was accompanied by accumulation of ROS. Co-treatment with antioxidant agent N-acetyl-l-cysteine (NAC) prevented ROS accumulation and pexophagy by modulating peroxisome protein levels and the association of NBR1, a pexophagy receptor with peroxisomes. Taken together, these findings demonstrate that catalase plays an important role in pexophagy during nutrient deprivation.

60 APPLIED LIFE SCIENCES↗