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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Preliminary Mechanical Design Study of the Hollow Electron Lens for HL-LHC

A Hollow Electron Lens (HEL) has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a hollow beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field. The first step of the design is the definition of the magnetic field that drives the electron trajectories. The estimation of such trajectories by means of a dedicated MATLAB tool is presented. The influence of the main geometrical and electrical parameters is analyzed and discussed. Then, the main mechanical design choices for the solenoids, cryostats gun and collector are described. The aim of this paper is to provide an overview of the feasibility study of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar devices.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Tailoring conductive networks within hollow carbon nanospheres to host phosphorus for advanced sodium ion batteries

The formidable sustainability challenges in advancing energy storage technologies call for game-changing research in battery designs. The previous pursuing of novel cathode materials with high redox potentials impedes the vast applications due to the simultaneous electrolyte decomposition at high potentials, though they are expected to deliver high specific capacities. Eventually, people start thinking in an opposite way, desirable anode materials with low redox potentials can also own high specific capacities. Among all the promising candidates, phosphorus-based anodes in sodium ion batteries (SIBs) have received considerable attention owing to the low cost and relatively high natural abundance of phosphorus. More importantly, phosphorus can store three sodium atoms and enable a high theoretical capacity of 2596 mAh g -1 , which overwhelms any other SIB anode currently available. However, the poor electronic conductivity and large volume change of phosphorus during cycling severely deteriorate battery performance. The most widely used strategy is to confine phosphorus within well-designed carbon hosts. Here, we thereby introduce a new type of porous hollow carbon with conductive-network interior as phosphorus host, which not only improves the electrical conductivity, but also creates enough interior surface for maximizing phosphorus utilization and shortening the ion's diffusion distance, compared to those conventional hollow carbon hosts. Therefore, the as-prepared red phosphorus-carbon spheres composites (RP/CS) exhibit superior rate performance (similar to 1083 mAh g -1 at 4 A g -1 , similar to 837 mAh g -1 even at 8 A g -1 ) and excellent cycle life (1027 mAh g -1 at 4 A g -1 more than 2000 cycles).

25 ENERGY STORAGE↗
DOE OSTI2016

Cobalt oxide-coated N- and B-doped graphene hollow spheres as bifunctional electrocatalysts for oxygen reduction and oxygen evolution reactions

Here, a simple and scalable method has been developed for the synthesis of Co 3 O 4 -coated N- and B-doped graphene hollow spheres (Co 3 O 4 /NBGHSs). These Co 3 O 4 /NBGHSs are highly active for both oxygen reduction and evolution reactions and can exhibit higher electrocatalytic activities and better durability than commercial Pt/C and RuO 2 /C, respectively, demonstrating them to be efficient bi-functional electrocatalysts. In-depth analysis shows that the coupling between Co 3 O 4 and NBGHSs, strong interaction with adsorbed O 2 , high electric conductivity, and the specific hollow structure play important roles in imparting the higher electrocatalytic activities to the Co 3 O 4 /NBGHSs. When tested as cathode catalysts for Zn–air batteries, the Co 3 O 4 /NBGHSs exhibit better performance and higher stability than the Pt/C catalyst and other catalysts reported previously. Lastly, this strongly suggests that the Co 3 O 4 /NBGHSs could be used as efficient electrocatalysts for metal–air batteries with great potential to replace precious metal/carbon based materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Stable Metal Anode enabled by Porous Lithium Foam with Superior Ion Accessibility

Abstract Lithium (Li) metal anodes have attracted much interest recently for high‐energy battery applications. However, low coulombic efficiency, infinite volume change, and severe dendrite formation limit their reliable implementation over a wide range. Here, an outstanding stability for a Li metal anode is revealed by designing a highly porous and hollow Li foam. This unique structure is capable of tackling many Li metal problems simultaneously: first, it assures uniform electrolyte distribution over the inner and outer electrode's surface; second, it reduces the local current density by providing a larger electroactive surface area; third, it can accommodate volume expansion and dissipate heat efficiently. Moreover, the structure shows superior stability compared to fully Li covered foam with low porosity, and bulky Li foil electrode counterparts. This Li foam exhibits small overpotential (≈25 mV at 4 mA cm −2 ) and high cycling stability for 160 cycles at 4 mA cm −2 . Furthermore, when assembled, the porous Li metal as the anode with LiFePO 4 as the cathode for a full cell, the battery has a high‐rate performance of 138 mAh g −1 at 0.2 C. The beneficial structure of the Li hollow foam is further studied through density functional theory simulations, which confirms that the porous structure has better charge mobility and more uniform Li deposition.

Hafez, Ahmed M.↗
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↗
DOE OSTI2014

Parallel vacuum arc discharge with microhollow array dielectric and anode

An electrode configuration with microhollow array dielectric and anode was developed to obtain parallel vacuum arc discharge. Compared with the conventional electrodes, more than 10 parallel microhollow discharges were ignited for the new configuration, which increased the discharge area significantly and made the cathode eroded more uniformly. The vacuum discharge channel number could be increased effectively by decreasing the distances between holes or increasing the arc current. Experimental results revealed that plasmas ejected from the adjacent hollow and the relatively high arc voltage were two key factors leading to the parallel discharge. The characteristics of plasmas in the microhollow were investigated as well. The spectral line intensity and electron density of plasmas in microhollow increased obviously with the decease of the microhollow diameter.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Growth behavior of LiMn{sub 2}O{sub 4} particles formed by solid-state reactions in air and water vapor

Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn{sub 2}O{sub 4} particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn{sub 2}O{sub 4} particles in air and water vapor atmospheres as model reactions; LiMn{sub 2}O{sub 4} is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO{sub 3} precursor impregnated with LiOH, LiMn{sub 2}O{sub 4} spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled. - Graphical abstract: This study has demonstrated a new strategy towards achieving morphology control without the use of additives during conventional solid-state reactions by exploiting water vapor-induced particle growth. - Highlights: • A new strategy to control the morphology of LiMn{sub 2}O{sub 4} particles is proposed. • Water vapor-induced particle growth is exploited in solid-state reactions. • The microstructural evolution of LiMn{sub 2}O{sub 4} particles is investigated. • The shape, size and microstructure can be controlled by solid-state reactions.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Revisit Carbon/Sulfur Composite for Li-S Batteries

To correlate the carbon properties e.g. surface area and porous structure, with the electrochemical behaviors of carbon/sulfur (C/S) composite cathodes for lithium-sulfur (Li-S) batteries, four different carbon frameworks including Ketjen Black (KB, high surface area and porous), Graphene (high surface area and nonporous), Acetylene Black (AB, low surface area and nonporous) and Hollow Carbon Nano Sphere (HCNS, low surface area and porous) are employed to immobilize sulfur (80 wt.%). It has been revealed that high surface area of carbon improves the utilization rate of active sulfur and decreases the real current density during the electrochemical reactions. Accordingly, increased reversible capacities and reduced polarization are observed for high surface area carbon hosts such as KB/S and graphene/S composites. The porous structure of KB or HCNS matrix promotes the long-term cycling stability of C/S composites but only at relatively low rate (0.2 C). Once the current density increases, the pore effect completely disappears and all Li-S batteries show similar trend of capacity degradation regardless of the different carbon hosts used in the cathodes. The reason has been assigned to the formation of reduced amount of irreversible Li2S on the cathode as well as shortened time for polysulfides to transport towards lithium anode at elevated current densities. This work provides valuable information for predictive selection on carbon materials to construct C/S composite for practical applications from the electrochemical point of view.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2017

High rate lithium-sulfur batteries enabled by mesoporous TiO{sub 2} nanotubes prepared by electrospinning

Graphical abstract: Mesoporous titanium dioxide nanotubes (MTDNTs) used as host for sulfur was prepared by electrospinning technique and subsequent thermal treatment. The nanotube walls of MTDNTs act as a host for sulfur and the hollow structure is favorable for the fast transmission of Li{sup +} ions. After sulfur was encapsulated into the pores of nanotube walls of MTDNTs, the MTDNTs/S composite electrode displays a relatively good cycling performance and especially excellent rate performance (about 610 mAh g-1 at 8 C). - Highlights: • Mesoporous titanium dioxide nanotubes (MTDNTs) were fabricated by electrospinning and subsequent thermal treatment. • MTDNTs was used as host for sulfur, TEM and SEM analysis showed that sulfur distributed in the meso pores of MTDNTs walls. • MTDNTs/S composite cathode delivers a reversible discharge capacity of 610 mAh g{sup −1} at a high current rate of 8 C. - Abstract: Mesoporous titanium dioxide nanotubes (MTDNTs) were prepared by electrospinning and subsequent thermal treatment. The as-synthesized MTDNTs possess anatase mischcrystal structure, hollow texture morphology, and a relatively high specific surface area of 93.6 m{sup 2} g{sup −1} with a pore volume of 0.2190 cm{sup −3} g{sup −1}. The nanotube walls of MTDNTs act as a host for sulfur and the hollow structure is favorable for the fast transmission of Li{sup +} ions. After sulfur was encapsulated into the pores of nanotube walls of MTDNTs, the MTDNTs/S composite electrode displays a relatively good cycling performance and especially excellent rate performance (about 610 mAh g{sup −1} at 8 C). The retention capacity can be up to 74.2% when the discharge rate increases from 0.5C to 8.0 C.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Recovery of critical elements from end-of-life lithium ion batteries with supported membrane solvent extraction

Single-stage and multi-stage systems and methods for the recovery of critical elements in substantially pure form from lithium ion batteries are provided. The systems and methods include supported membrane solvent extraction using an immobilized organic phase within the pores of permeable hollow fibers. The permeable hollow fibers are contacted by a feed solution on one side, and a strip solution on another side, to provide the simultaneous extraction and stripping of elements from dissolved lithium ion cathode materials, while rejecting other elements from the feed solution. The single- and multi-stage systems and methods can selectively recover cobalt, manganese, nickel, lithium, aluminum and other elements from spent battery cathodes and are not limited by equilibrium constraints as compared to traditional solvent extraction processes.

Bhave, Ramesh R.↗
DOE OSTI2015

Low work-function thermionic emission and orbital-motion-limited ion collection at bare-tether cathodic contact

With a thin coating of low-work-function material, thermionic emission in the cathodic segment of bare tethers might be much greater than orbital-motion-limited (OML) ion collection current. The space charge of the emitted electrons decreases the electric field that accelerates them outwards, and could even reverse it for high enough emission, producing a potential hollow. In this work, at the conditions of high bias and relatively low emission that make the potential monotonic, an asymptotic analysis is carried out, extending the OML ion-collection analysis to investigate the probe response due to electrons emitted by the negatively biased cylindrical probe. At given emission, the space charge effect from emitted electrons increases with decreasing magnitude of negative probe bias. Although emitted electrons present negligible space charge far away from the probe, their effect cannot be neglected in the global analysis for the sheath structure and two thin layers in between sheath and the quasineutral region. The space-charge-limited condition is located. It is found that thermionic emission increases the range of probe radius for OML validity and is greatly more effective than ion collection for cathodic contact of tethers.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

Metal-organic framework-derived Nickel Cobalt oxysulfide nanocages as trifunctional electrocatalysts for high efficiency power to hydrogen

Here we report a synthesis of nickel cobalt oxysulfide nanocage trifunctional electrocatalysts by sulfurizing zeolitic imidazolate framework-67. Benefiting from the synergistic coupling of nickel cobalt oxysulfide and N-doped carbon polyhedron in a hollow dodecahedral structure, the nickel cobalt oxysulfide nanocages exhibit superior trifunctional electrocatalytic activity and durability towards oxygen reduction and evolution, and hydrogen evolution reactions in alkaline conditions. Moreover, the nickel cobalt oxysulfide nanocage trifunctional electrocatalysts are used in an air cathode for a rechargeable zinc-air battery and in both anode and cathode for overall water splitting, where the water splitting is directly powered by the assembled zinc-air battery. Such integrative power-to-hydrogen device can operate stably over 17 h without visible energy efficiency losses for hydrogen gas production.

08 HYDROGEN↗
DOE OSTI2017

Effects of the particle properties on electrochemical performance of nanocrystalline LiAl 0.1 Cu 0.1 Mn 1.8 O 4 cathode materials prepared by ultrasonic spray pyrolysis

LiAl 0.1 Cu 0.1 Mn 1.8 O 4 particles were prepared by the ultrasonic spray pyrolysis using nitrate salts at 800 °C in air atmosphere. The effects of ultrasonic frequency (120 kHz and 2.4 MHz) of the atomizer on the particle properties were investigated by X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive spectroscopy. In addition, cyclic voltammetry and galvanostatic tests were performed to study the influence of the particle structure on the electrochemical behavior in Li-ion battery half-cell. Particle characterization studies reveal that the LiAl 0.1 Cu 0.1 Mn 1.8 O 4 particles have a nanocrystalline spinel structure. The secondary particles have a spherical morphology and the average particle size of the samples decreases with increase in frequency from 3.5 μm to 770 nm. Both samples have porous and partly hollow structure. The initial discharge capacities of LiAl 0.1 Cu 0.1 Mn 1.8 O 4 particles produced using 120 kHz and 2.4 MHz atomizers are 82 and 75 mAh·g -1 , respectively, between 3.0 and 4.8 V at 0.1C rate. Discharge capacities at the 4 V potential region drop to 85% of the initial values for both samples after 110 cycles. Although the micron-sized LiAl 0.1 Cu 0.1 Mn 1.8 O 4 particles exhibit higher capacity at 0.1C than the finer particles, the cathode prepared from the submicron particles has a better rate capability with a retention of the discharge capacity that is 3 times higher at 4C rate.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Beyond the Polysulfide Shuttle and Lithium Dendrite Formation: Addressing the Sluggish Sulfur Redox Kinetics for Practical High‐Energy Li‐S Batteries

Abstract Electrolyte modulation simultaneously suppresses polysulfide the shuttle effect and lithium dendrite formation of lithium–sulfur (Li‐S) batteries. However, the sluggish S redox kinetics, especially under high S loading and lean electrolyte operation, has been ignored, which dramatically limits the cycle life and energy density of practical Li‐S pouch cells. Herein, we demonstrate that a rational combination of selenium doping, core–shell hollow host structure, and fluorinated ether electrolytes enables ultrastable Li stripping/plating and essentially no polysulfide shuttle as well as fast redox kinetics. Thus, high areal capacity (>4 mAh cm −2 ) with excellent cycle stability and Coulombic efficiency were both demonstrated in Li metal anode and thick S cathode (4.5 mg cm −2 ) with a low electrolyte/sulfur ratio (10 μL mg −1 ). This research further demonstrates a durable Li‐Se/S pouch cell with high specific capacity, validating the potential practical applications.

Zhao, Chen↗
DOE OSTI2020

Beyond the Polysulfide Shuttle and Lithium Dendrite Formation: Addressing the Sluggish Sulfur Redox Kinetics for Practical High-Energy Li-S Batteries

Electrolyte modulation simultaneously suppresses polysulfide the shuttle effect and lithium dendrite formation of lithium-sulfur (Li-S) batteries. However, the sluggish S redox kinetics, especially under high S loading and lean electrolyte operation, has been ignored, which dramatically limits the cycle life and energy density of practical Li-S pouch cells. In this work, we demonstrate that a rational combination of selenium doping, core-shell hollow host structure, and fluorinated ether electrolytes enables ultrastable Li stripping/plating and essentially no polysulfide shuttle as well as fast redox kinetics. Thus, high areal capacity (>4 mAh cm -2 ) with excellent cycle stability and Coulombic efficiency were both demonstrated in Li metal anode and thick S cathode (4.5 mg cm -2 ) with a low electrolyte/sulfur ratio (10 mu L mg(-1)). Overall, this research further demonstrates a durable Li-Se/S pouch cell with high specific capacity, validating the potential practical applications.

25 ENERGY STORAGE↗
DOE OSTI2018

Sulfur containing nanoporous materials, nanoparticles, methods and applications

Sulfur containing nanoparticles that may be used within cathode electrodes within lithium ion batteries include in a first instance porous carbon shape materials (i.e., either nanoparticle shapes or "bulk" shapes that are subsequently ground to nanoparticle shapes) that are infused with a sulfur material. A synthetic route to these carbon and sulfur containing nanoparticles may use a template nanoparticle to form a hollow carbon shape shell, and subsequent dissolution of the template nanoparticle prior to infusion of the hollow carbon shape shell with a sulfur material. Sulfur infusion into other porous carbon shapes that are not hollow is also contemplated. A second type of sulfur containing nanoparticle includes a metal oxide material core upon which is located a shell layer that includes a vulcanized polymultiene polymer material and ion conducting polymer material. The foregoing sulfur containing nanoparticle materials provide the electrodes and lithium ion batteries with enhanced performance.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Advanced composite applications for sub-micron biologically derived microstructures

A major thrust of advanced material development is in the area of self-assembled ultra-fine particulate based composites (micro-composites). The application of biologically derived, self-assembled microstructures to form advanced composite materials is discussed. Hollow 0.5 micron diameter cylindrical shaped microcylinders self-assemble from diacetylenic lipids. These microstructures have a multiplicity of potential applications in the material sciences. Exploratory development is proceeding in application areas such as controlled release for drug delivery, wound repair, and biofouling as well as composites for electronic and magnetic applications, and high power microwave cathodes.

Schnur, J. M.↗
DOE OSTI2017

Revealing the reaction mechanisms of Li–O2 batteries using environmental transmission electron microscopy

The capacity, Coulombic efficiency, rate, and cyclability of a Li-O2 battery critically depend on the electrode reaction mechanism and the structure/morphology of the reaction product as well as their spatial and temporal evolution1-8, which are all further complicated by the choice of different electrolyte. For the case of aprotic cell, the discharge product, Li2O2, is formed through solution and surface mechanisms9,10, but little is known on the formation mechanism of the perplexing morphology of the reaction product11-15. For the case of Li-O2 battery using solid electrolyte, neither electrode reaction mechanism nor the nature of the reaction production is known. Herein, we reveal the full cycle reaction pathway for Li-O2 batteries and its correlation with the nature of the reaction product. Using an aberration-corrected environmental TEM under oxygen environment, we captured, for the first time, the morphology and phase evolution on the carbon nanotube (CNT) cathode of a working solid-state Li-O2 nano-battery16 and directly correlated these features with electrochemical reaction. We found that the oxygen reduction reaction on CNTs initially produces LiO2, which subsequently evolves to Li2O2 and O2 through disproportionation reaction. Surprisingly it is just the releasing of O2 that inflates the particles to a hollow structure with a Li2O outer surface layer and Li2O2 inner-shell, demonstrating that, in general, accommodation of the released O2 coupled with the Li+ ion diffusion and electron transport paths across both spatial and temporal scales critically governs the morphology of the discharging/charging product in Li-O2 system. We anticipate that the direct observation of Li-O2 reaction mechanisms and their correlation with the morphology of the reaction product set foundation for quantitative understanding/modeling of the electrochemical processes in the Li-O2 system, enabling rational design of both solid-state and aprotic Li-O2 batteries.

25 ENERGY STORAGE↗