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At least 37 records · Page 2

Flow visualization in high-energy-density laboratory plasmas

Flow visualization is often essential for evaluating high-energy-density (HED) laboratory plasmas, examining their dynamics, and assessing design strategies. However, imaging at fine phenomenological flow scales is a major challenge. Here, a zone-plate–based radiography system tailored for applications in HED physics is demonstrated. The burst-mode radiography system combines a dual-flash laser-generated x-ray source, a high-magnification zone plate optic, and a multiple frame hybrid complementary metal-oxide-semiconductor (hCMOS) sensor for image detection. Operating at a magnification of 42 x⁠, a pair of radiographs is measured in rapid succession, each time gated by a 4.75 keV flash of x rays lasting 100 ps. The system achieves a spatial resolution below 3 μm. The potential of this approach for applications in HED physics is exemplified by observing small-scale spike morphologies at a pusher-foam interface impacted by a strong, laser-driven blast wave.

Flow instabilities

Particle-in-cell simulations of expanding high energy density plasmas with laser ray tracing

The design and analysis of high energy density (HED) laser experiments typically rely on radiation hydrodynamics simulations. However, some laser–plasma interaction regimes are not collisional and cannot be adequately modeled with hydrodynamics. For example, strongly driven magnetic reconnection and magnetized collisionless shock experiments possess extended hydrodynamic or even kinetic properties, necessitating first-principles kinetic simulations. In this paper, we present the benchmarking and first results obtained with a laser-ray-tracing and inverse bremsstrahlung absorption module implemented in the particle-in-cell code PSC. The simulation results are compared to radiation hydrodynamic simulations using the FLASH code as well as analytical estimates. We successfully benchmark the energy deposition model and overall hydrodynamic evolution of the systems. We also consider possible kinetic effects that may be expected from laser-target ablation in the HED regime, including non-local transport and two-temperature effects.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Development of Li–S Battery Cells with High Energy Density and Long Cycling Life

Lithium–sulfur (Li–S) batteries are considered one of the most promising next-generation energy storage technologies for electric vehicles, owing to their high energy density (up to three times greater than current lithium-ion batteries) and the low cost of sulfur (approximately 100 times cheaper than conventional cobalt oxide). However, several challenges hinder their commercial viability, including the electronically and ionically insulating nature of sulfur, polysulfide dissolution, and lithium dendrite growth. These issues significantly limit battery energy density and cycle life and must be addressed to enable successful commercialization. Current strategies involving porous carbon structures, additives, and electrocatalyst engineering have not fully resolved the polysulfide dissolution problem. While polysulfide-free cathode materials offer a promising solution, they often suffer from low sulfur content, leading to reduced discharge capacity and sluggish reaction kinetics. To overcome these limitations, we have developed novel soluble-polysulfide-free sulfur cathode active materials with a high sulfur content (>50 wt%). By integrating these cathodes with functional binders, optimized electrolyte formulations, and refined electrode fabrication techniques, we demonstrate Li–S batteries with both high energy density and long cycle life. This advancement brings the realization of low-cost, high-energy Li–S batteries significantly closer to practical application.

25 ENERGY STORAGE

Upcycling mixed cathode materials to high-energy-density LiFe 0.75 Mn 0.25 PO 4

To address the demand for next-generation cathode materials with high energy density, upcycling LiFePO 4 into LiFe 0.75 Mn 0.25 PO 4 has attracted considerable attention. Nevertheless, existing strategies have yet to achieve both morphology and full elemental recovery under mild ambient conditions. Here, we report an upcycling route that can address this issue by combining leaching and a high-temperature treatment process. The upcycled LiFe 0.75 Mn 0.25 PO 4 exhibits enlarged lattice spacing and a high discharge plateau, and it delivers an energy density of 563.7 Wh/kg, 40.3 Wh/kg higher than recycled LiFePO 4 , which indicates the high value of the proposed upcycling strategy. At 1 C, LiFe 0.75 Mn 0.25 PO 4 also exhibits excellent cycling stability of 91% over 700 cycles. Techno-economic analysis also indicates impressive economic and environmental benefits, including 10.4% less raw materials usage and 12.2% less energy consumption and wastewater generation. This work demonstrates a scalable and economic upcycling strategy and provides a promising pathway for sustainable battery upcycling compatible with industrial conditions.

LMFP

Pulse Power Capability Of High Energy Density Capacitors Based on a New Dielectric Material

A new dielectric composite consisting of a polymer coated onto a high-density metallized Kraft has been developed for application in high energy density pulse power capacitors. The polymer coating is custom formulated for high dielectric constant and strength with minimum dielectric losses. The composite can be wound and processed using conventional wound film capacitor manufacturing equipment. This new system has the potential to achieve 2 to 3 J/cu cm whole capacitor energy density at voltage levels above 3.0 kV, and can maintain its mechanical properties to temperatures above 150 C. The technical and manufacturing development of the composite material and fabrication into capacitors are summarized in this paper. Energy discharge testing, including capacitance and charge-discharge efficiency at normal and elevated temperatures, as well as DC life testing were performed on capacitors manufactured using this material. TPL (Albuquerque, NM) has developed the material and Aerovox (New Bedford, MA) has used the material to build and test actual capacitors. The results of the testing will focus on pulse power applications specifically those found in electro-magnetic armor and guns, high power microwave sources and defibrillators.

Winsor, Paul

Molecular Interlocking Multidimensional Modulations of Cathode‐Electrolyte Interface for Constructing High Energy Density Quasi‐Solid‐State Batteries

Gel polymers are regarded as a promising candidate electrolyte for lithium-metal quasi-solid-state batteries, primarily due to their high ionic conductivity and solid-liquid synergistic properties. However, challenges such as interfacial side reactions, limitations in Li + transport caused by interfacial issues, and leaching of transition metals from the cathode have yet to be effectively solved. Herein, a novel gel electrolyte modulation strategy based on electrostatic filler assembly is proposed to address the issues of ineffective capacity utilization and inadequate cycling stability of high-energy-density cathode materials in solid-state lithium-ion batteries. It constructs a 3D interpenetrating charge-bridge network that effectively tackles the phase-separation challenge between fillers and electrolytes at the molecular level. Meanwhile, the molecular interlocking structure effectively inhibits the electrolyte erosion. More critically, it optimizes and stabilizes the cathode-electrolyte interface film, which facilitates the conduction of Li + -ions through a size-sieving mechanism. Consequently, this strategy enables effective adaptation across diverse high-energy-density cathode materials with satisfactory capacity performance (170.4 mAh g −1 at 4.5 V/1 C for LiNi 0.6 Co 0.2 Mn 0.2 O 2 and 194.0 mAh g −1 at 4.3 V/1 C for LiNi 0.9 Co 0.08 Mn 0.02 O 2 ). In conclusion, this investigation offers a straightforward and effective reference for addressing the critical challenges of ionic transport and interface stabilization in the design of gel electrolytes.

cathode-electrolyte interface

Measurement of interfacial thermal resistance in high-energy-density matter

Heat transport across interfaces is a ubiquitous phenomenon with many unresolved aspects. In particular, it is unknown if an interfacial thermal resistance (ITR) occurs in matter with high-energy-density where free electrons dominate the heat conduction. Here, we report on the first experimental evidence that a significant heat barrier is present between two different regions of high-energy-density matter: a strongly heated tungsten wire and a surrounding plastic layer that stays relatively cold. We use diffraction-enhanced imaging to track the time evolution of density discontinuities and reconstruct the temperature evolution in the quasi-stationary stage. The clear signatures of a temperature jump demonstrate the importance of the ITR for strongly heated systems with far-reaching implications for interpreting experiments and applications like inertial confinement fusion.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Development and characterization of a laser-gated, high resolution x-ray radiography platform for high energy density experiments using toroidally bent crystals

Bent crystal x-ray imagers are a well-established diagnostic tool to study high energy density (HED) objects by acquiring two-dimensional x-ray radiographs. Often, studying these HED objects requires very high spatial resolution, which is limited by astigmatism when using spherically bent crystals. By using toroidal-shaped crystals instead, astigmatism can be reduced and the overall spatial resolution of the instrument improved. Here, the development and characterization of a laser-gated x-ray radiography platform at the National Ignition Facility using a toroidal crystal is presented. This includes measurements of the spatial and temporal profile, which is determined by the x-ray source. In conclusion, to properly validate the reduced astigmatism, a new multi-plane grid approach was implemented, which, for the first time, allows a depth of field measurement, alignment verification and x-ray source size estimate in a single shot, demonstrating the current platform’s capability to provide sub-10 μm resolution over a 0.9 mm depth of field with a temporal resolution of 110 ps.

Crystal optics

High energy density micro-fiber based nickel electrode for aerospace batteries

The nickel electrode is the specific energy limiting component in battery systems such as nickel-hydrogen, nickel-metal hydride and nickel-zinc. Lightweight, high energy density nickel electrodes have been developed which deliver in excess of 180 mAh/g at the one-hour discharge rate. These electrodes are based on a highly porous, nickel micro-fiber (less than 10 micron diameter) substrate, electrochemically impregnated with nickel-hydroxide active material. Electrodes are being tested both as a flooded half-cell and in full nickel-hydrogen and nickel-metal hydride cells. The electrode technology developed is applicable to commercial nickel-based batteries for applications such as electric vehicles, cellular telephones and laptop computers and for low-cost, high energy density military and aerospace applications.

Francisco, Jennifer

Charged-particle transport in high energy density plasmas

This Special Topic Collection grew out of two gatherings of researchers active in the high energy density (HED) physics community: a mini-conference on charged-particle transport in HED plasma held during the 64th annual meeting of the American Physical Society's Division of Plasma Physics (Spokane, WA, November 2022) and a dedicated charged-particle transport coefficient code comparison workshop (Livermore, CA, July 2023). These gatherings provided opportunities for theoretical, computational, and experimental researchers to discuss the state of the field, including current capabilities and methods, needs of hydrodynamic simulations, and frontiers for future research. Finally, this special issue collects a total of 13 research and review articles on charged-particle transport in HED plasmas.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY

High-energy-density cylindrical capacitors

Manufacturing technique produces high quality metalized-film cylindrical capacitors of energy density greater than 0.1 J/g uncased, using either 24-gage polyvinylidene flouride or 14-gage polycarbonate film. Components are wound wrinkle-free on hollow PTFE cores, using winding machine that applies constant dynamically controlled tension to film during winding operation.

Parker, R. D.

New Engineering Concepts to High Energy Density Li-S Batteries

Li-S batteries (LSBs) with energy densities > 500 Wh/kg @ C/5 and >1000 cycles, cycle life operating over wide temperatures has been identified to be critical for meeting the global energy demands. Progress is however, very much limited due to several major hurdles related to the following: (a) poor Li' reaction kinetics (conductivity/diffusivity) enabling full reversible S conversion to Li2S, (b) inferior electron (e) conductivity, specific capacity and cycle life due to electrolyte soluble species of polysulfides (PSs) formed with the reaction of Li ions with sulfur migrating to anode, (c) unstable solid electrolyte interphase (SEI) formation and finally, (d) dendrites that are formed on the Li metal anode severely limiting the cycle life due to polarization at the solid/liquid interfaces causing safety, inferior capacity, energy density, rate, and cycle life issues. Creation of a fully functional economical ≤$80/kWh, high energy density LSBs is vital for enabling its widespread commercial deployment and use in current and next generation electric vehicles.

25 ENERGY STORAGE

Demonstration of x-ray fluorescence spectroscopy as a sensitive temperature diagnostic for high-energy-density physics experiments

We present the use of x-ray fluorescence spectroscopy (XFS) to a sensitive temperature diagnostic in shocked foams at temperatures of 30–75 eV. Cobalt-doped foams were shock compressed using a planar drive at the OMEGA laser facility and photo-pumped with a Zn He⁢𝛼 x-ray source. Analysis of the resulting cobalt 𝐾⁢𝛽 x-ray fluorescence spectra using collisional radiative codes allows the temperature to be determined in the shocked foams. Furthermore, this method provides a sensitive and robust technique to determine temperatures in high-energy-density physics experiments in the tens of electronvolts temperature range. In these experiments, we find that radiation hydrodynamic simulations predict a lower temperature in the shocked foams compared to analysis of the XFS data using collisional radiative models. Although additional experiments with an independent temperature diagnostic to absolutely calibrate XFS spectra for these conditions will be required to resolve this discrepancy, these results demonstrate the excellent temperature sensitivity of XFS spectra for high-energy-density physics experiments.

Atomic spectra