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At least 19 records

LICS Modeling [Slides]

We propose to design a new diagnostic based on laser inverse Compton scattering (LICS) to study the dynamics of runaway electron formation during killer-pellet triggered disruptions in DIII-D, and their subsequent loss. Obtaining a better understanding of transient runaway electrons (and how to suppress them) is one of the highest priorities of the US fusion program. To enable this, we need better measurements of the runaway electron population during and after disruptions. We intend to measure point-wise time-resolved spatial profile and energy distributions of the runaway electrons while they are in the core of the tokamak plasma. While LICS measurements of relativistic e-beams have been successfully made on accelerators, they have never been done in a tokamak. We bring two innovations to this diagnostic concept which should enable 10 times better signal-to-noise ratios than previously envisioned. In particular, we will marry bright short pulse (10’s of picosecond) laser technologies with the availability of short-pulse gated x-ray imagers developed at Los Alamos for the National Ignition Facility (NIF), to reject noise generated by the tokamak and plasma environment. We will generate a Conceptual Physics Basis, a Preliminary Design, and a Final Design package, with associated DIII-D reviews, along with prototype component testing for the diagnostic over the course of the two year duration of this proposal.

42 ENGINEERING↗

Materials Data on LiC by Materials Project

LiC crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Li is bonded in a 2-coordinate geometry to six equivalent C atoms. There are two shorter (2.21 Å) and four longer (2.38 Å) Li–C bond lengths. C is bonded in a 7-coordinate geometry to six equivalent Li and one C atom. The C–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗

Materials Data on LiCS(OF)3 by Materials Project

LiCF3SO3 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of four fluoroform molecules and one SO3Li sheet oriented in the (0, 0, 1) direction. In the SO3Li sheet, Li1+ is bonded to four O2- atoms to form edge-sharing LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.91–2.02 Å. S4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.45 Å) and one longer (1.48 Å) S–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Li1+ and one S4+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Li1+ and one S4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S4+ atom.

36 MATERIALS SCIENCE↗

Structural Evolution and Transition Dynamics in Lithium Ion Battery under Fast Charging: An Operando Neutron Diffraction Investigation

Abstract Fast charging (<15 min) of lithium‐ion batteries (LIBs) for electrical vehicles (EVs) is widely seen as the key factor that will greatly stimulate the EV markets, and its realization is mainly hindered by the sluggish diffusion of Li + . To have a mechanistic understanding of Li + diffusion within LIBs, in this study, structural evolutions of electrodes for a Ni‐rich LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) || graphite cylindrical cell with high areal loading (2.78 mAh cm −2 ) are developed for operando neutron powder diffraction study at different charging rates. Via sequential Rietveld refinements, changes in structures of NMC622 and Li x C 6 are obtained during moderate and fast charging (from 0.27 C to 4.4 C). NMC622 exhibits the same structural evolution regardless of C‐rates. For phase transitions of Li x C 6 , the stage I (LiC 6 ) phase emerges earlier during the stepwise intercalation at a lower state of charge when charging rate is increased. It is also found that the stage II (LiC 12 ) → stage I (LiC 6 ) transition is the rate‐limiting step during fast charging. The LiC 12 → LiC 6 transition mechanism is further analyzed using the Johnson–Mehl–Avrami–Kolmogorov model. It is concluded as a diffusion‐controlled, 1D phase transition with decreasing nucleation kinetics under increasing chargingrates.

25 ENERGY STORAGE↗

In-situ formation of stable interface towards Li-in anode for halide solid-state electrolyte

Halide-based solid-state electrolytes (SSEs) are promising candidates for next-generation all-solid-state lithium batteries (ASSLBs) due to their high ionic conductivity and chemical stability. However, their poor interfacial compatibility with lithium metal anode and Li-In alloy significantly hinder practical application due to the requirement for a protective interlayer. In this study, a novel approach to overcome this limitation is presented by introducing iron (Fe) doping into Li 3 InCl 6 (LIC), which enables direct and stable contact with lithium-indium (Li-In) metal without a protective interlayer. Thermodynamic and computational analyses identified Fe 3+ as a suitable dopant based on its similar reduction potential to In 3+ and structural compatibility within the halide lattice. The synthesized 10 at. % Fe-doped LIC exhibits high phase purity, retained ionic conductivity, and notably improved interfacial stability. Full-cell tests using Fe-LIC achieve over 300 cycles with 80 % capacity retention. At the same time, symmetric Li-In/ Fe-LIC/ Li-In cells sustain over 500 h of operation, representing the first reported long-term cycling of LIC-based ASSLB without a protective interlayer. In conclusion, this work establishes Fe doping as an effective strategy to stabilize halide SSEs of In system against Li-In alloy, thereby simplifying cell architecture and advancing the development of safer, high-performance halide-based solid-state electrolytes.

Halide-based solid-state electrolytes↗

Charge-Based Droop Control Addressing Control Saturation for Low-Inertia Converters

With bulky dc-link capacitors/inductors, traditional voltage-source converters (VSCs) and current-source converters (CSCs) feature a large inertia to facilitate the converter control under large transients. To achieve high power density with reduced cost, low-inertia converters (LICs) featuring significantly reduced dc-link capacitors/inductors have attracted growing attention. However, without bulky dc-link energy buffer, LICs are prone to control saturation under large transients, resulting in undesired oscillation and instability. This issue cannot be managed by traditional proportional-integral based control due to the low inertia. And it will deteriorate when several LICs are connected in series. To address this challenge in LICs, a model-predictive control (MPC) with a computation-inexpensive feed-forward compensation method has been proposed to provide fast dynamic responses. But it would suffer control saturation under larger transients that degrades the control performance. In this article, a charge-based droop control (CDC) is proposed to address this remaining challenge. This paper firstly analyzes the control saturation challenge in LICs by using a tri-port soft-switching solid-state transformer as an example. Next, the operating principle of the proposed CDC are introduced. Two different implementation approaches are discussed in detail. Lastly, the proposed scheme is validated in simulation with a high-fidelity model of hardware prototype. As a result, the proposed CDC eliminated the 2 kHz oscillation and reduced the dc-link ripple and overshoot due to control saturation by 75% and 50%, respectively.

30 DIRECT ENERGY CONVERSION↗

Promising performance of sulfide catholytes compared to halide alternatives in NMC811 cathodes for sheet-type sulfide solid-state batteries

Sulfide-based solid-state batteries (SSBs) show promise in achieving energy densities over 350 Wh/kg, yet challenges persist with their incorporation of high-voltage, nickel-rich layered oxide cathodes, such as LiNi₀.₈Mn₀.₁Co₀.₁O₂ (NMC811), due to the poor oxidation stability of sulfide solid-state electrolytes (SSEs) like Li₆PS₅Cl (LPSCl). Although halide SSEs such as Li₃InCl₆ (LIC) and Li₃YCl₆ (LYC) have previously shown promise in stabilizing high-voltage NMC cathodes, our research reveals that sulfide SSE catholytes, particularly when combined with surface-coated NMC cathodes, deliver superior performance. Here, this investigation assesses the cycling stability of various catholytes—LPSCl, LIC, Li₁₀GeP₂S₁₂ (LGPS), combined LIC-LPSCl, and LYC-LPSCl—in SSBs with LiNbO₃-coated NMC811 cathodes against sheet-type LPSCl separators. Findings indicate that while LGPS-based cathodes maintain higher capacity retention, they yield lower deliverable capacity, and LIC cathodes experience significant electrochemical degradation. Importantly, our results underscore that sulfide SSE catholytes, in conjunction with LiNbO₃-coated cathodes, optimize the cathode-electrolyte interphase (CEI), enhancing both kinetics and mass transport. These insights provide a strategic direction for optimizing catholyte composition in the development of sheet-type sulfide-based SSBs.

Catholyte↗

Dissecting Disorder: Defect-Driven Structural Complexity in Layered Li3InCl6 Solid Electrolyte

Halide solid electrolytes have emerged as promising candidates for solid-state batteries owing to their high oxidative stability and ionic conductivity. Among them, Li3InCl6 (LIC) has attracted significant attention. However, diffraction patterns of LIC synthesized via different methods exhibit distinct differences particularly at low-angle reflectionsindicative of underlying structural disorder. These variations are attributed to deviations from ideal crystallographic order, especially stacking faults, whose impact on structure and ion transport remains poorly understood. Here, we identify and quantify stacking faults in LIC samples prepared under different synthetic conditions. Using X-ray diffraction and time-of-flight neutron diffraction, we construct and refine stacking fault models that accurately reproduce the experimental diffraction features. LIC samples with higher degrees of stacking faults exhibit only negligible differences in ionic conductivities and activation energies. This indicates that stacking faults have a limited impact on altering the Li+ diffusion pathway along the c-axis, likely due to the high concentration of vacancies in the In layers, while Li+ diffusion remains nearly unchanged in the ab-plane. Our results account for the observed differences in diffraction patterns across samples and provide a quantitative assessment of faulting probabilities and stacking sequences. The insights gained from this study are expected to be broadly applicable to other layered halide solid electrolytes and contribute to a deeper understanding of the role of structural disorder in ion transport.

Liu, Jue [ORNL] (ORCID:000000024453910X)↗

Optimization of catholyte for halide-based all-solid-state batteries

Halide solid electrolytes gain significant attention due to their high ionic conductivity, low processing temperature, dry air compatibility, and high-voltage stability. However, low cathode active material (CAM) loading in the composite cathode constrains the realization of high energy density for halide-based all-solid-state batteries. In this study, three halide materials, raw Li 3 YBrCl 5 (LYBC-R, <30μm), milled LYBC (LYBC-M, <5 μm) and freeze-dried Li 3 InCl 6 (LIC, <500 nm), were used as catholytes, combined with LYBC-M as the electrolyte and LiIn alloy as the anode. The CAM:catholyte ratio was investigated as well as stack pressure and operating temperature. Our study demonstrates that particle size of the catholyte plays an important role only for high CAM loading or high C-rate cycling. At moderate CAM loading (65 and 70wt% LiNi 0.83 Mn 0.06 Co 0.11 O 2 ) and 0.1 C-rate, all the three catholytes perform well, providing initial discharge capacities >177 mAh/g. At high CAM loading (85wt%) and 0.1 C-rate, a cathode with the nano-scale LIC catholyte provides discharge capacity of 175 mAh/g, while the larger particle size catholytes suffer significantly reduced capacity. Both LYBC and LIC catholytes provided capacity retention >80% after 200 cycles at 0.5C. These results imply that cathode particle size is critically important for performance at high CAM loading. Furthermore, both electrolyte and cathode were tape cast to scale up size and prepare realistic layer thicknesses. A small amount of binder was used in both layers, to balance the electrochemical performance and mechanical properties. Further, the discharge capacity of a tape cell was 152mA h/g at 0.1C with a capacity retention of 81.8% after 20 cycles at 0.5C. The results demonstrate the excellent performance of LYBC as an electrolyte, and provide guidance for halide-based cathode design.

25 ENERGY STORAGE↗

Controlling MoO 2 and MoO 3 phases in MoO x /CNTs nanocomposites and their application to anode materials for lithium-ion batteries and capacitors

Molybdenum oxides (MoO 2 and MoO 3 ) are attractive anode materials for Li- and Na- ion batteries. Although there have been extensive studies on them individually, systematic and comparative studies are still lacking. Here, we demonstrate a facile and straightforward synthesis method to control the phase and oxidation state in the MoO x /CNTs nanocomposites via hydrothermal reaction followed by heat-treatment. By changing the gas atmosphere during the annealing process, well-dispersed MoO 2 /CNTs and MoO 3 /CNTs nanocomposites are formed without altering their overall morphology. This strategy enables us to investigate the true structure-property correlation of MoO x /CNTs nanocomposites by comparing the structure and electrochemical properties of MoO 2 /CNTs and MoO 3 /CNTs. When tested as anode materials for lithium-ion batteries, both HT-MoO 2&3 /CNTs electrodes show much-improved cycling stability and rate performance compared to the rod-shaped bulk MoO 3 electrode. In situ Mo K-edge x-ray absorption spectroscopy (XAS) has been further employed to compare and elucidate Li + storage mechanisms of both electrodes. When employed to the negative electrode of a high-power lithium-ion capacitor (LIC), the LIC full-cell composed of HT-MoO 3 /CNTs negative and activated carbon positive electrodes demonstrates impressive energy and power densities (~ 90 Wh kg –1 with 2000 W kg –1 ) and excellent cycling stability (96.8 % capacity retention after 300 cycles), revealing the versatility of the MoO x /CNTs electrodes in energy applications.

25 ENERGY STORAGE↗

Homoleptic Perchlorophenyl “Ate” Complexes of Thorium(IV) and Uranium(IV)

The reaction of AnCl 4 (DME) n (An = Th, n = 2; U, n = 0) with 5 equiv of LiC 6 Cl 5 in Et 2 O resulted in the formation of homoleptic actinide-aryl “ate” complexes [Li(DME) 2 (Et 2 O)] 2 [Li(DME) 2 ][Th(C 6 Cl 5 ) 5 ] 3 ([Li][1]) and [Li(Et 2 O) 4 ][U(C 6 Cl 5 ) 5 ] ([Li][2]). Similarly, the reaction of AnCl 4 (DME)n (An = Th, n = 2; U, n = 0) with 3 equiv of LiC 6 Cl 5 in Et 2 O resulted in the formation of heteroleptic actinide-aryl “ate” complexes [Li(DME) 2 (Et 2 O)][Li(Et 2 O) 2 ][ThCl 3 (C 6 Cl 5 ) 3 ] ([Li][3]) and [Li(Et 2 O) 3 ][UCl 2 (C 6 Cl 5 ) 3 ] ([Li][4]). Density functional calculations show that the An–C ipso σ-bonds are considerably more covalent for the uranium complexes vs the thorium analogues, in line with past results. Additionally, good agreement between experiment and calculations is obtained for the 13 C ipso NMR chemical shifts in [Li][1] and [Li][3]. Here, the calculations demonstrate a deshielding by ca. 29 ppm from spin–orbit coupling effects originating at Th, which is a direct consequence of 5f orbital participation in the Th–C bonds.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Effects of catholyte aging on high-nickel NMC cathodes in sulfide all-solid-state batteries

Sulfide solid-state electrolytes (SSEs) in all-solid-state batteries (SSBs) are recognized for their high ionic conductivity and inherent safety. The LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathode offers a high thermodynamic potential of approximately 3.8 V vs. Li/Li + and a theoretical specific capacity of 200 mA h g −1 . However, the practical utilization of NMC811 in sulfide SSBs faces significant interfacial challenges. The oxidation instability of sulfide solid electrolytes against NMC811 and the formation of the cathode electrolyte interphase (CEI) during cycling lead to degradation and reduced cell performance. Volumetric changes in NMC during lithiation and de-lithiation can also cause detachment from sulfide electrolytes or internal particle cracking. Despite extensive galvanostatic cycling studies to address the issues, the calendar life of sulfide SSBs remains poorly understood. Here, we systematically studied the effects of four different catholytes on the calendar aging of LiNbO 3 (LNO)-coated NMC811, including Li 6 PS 5 Cl (LPSCl), Li 3 InCl 6 –Li 6 PS 5 Cl (LIC–LPSCl), Li 3 YCl 6 –Li 6 PS 5 Cl (LYC–LPSCl), and Li 10 GeP 2 S 12 (LGPS). Our results indicate that LPSCl provides optimal capacity retention when stored at high state-of-charge (SOC) at room temperature, but the LIC–LPSCl cathode shows significant capacity degradation and chemical incompatibility. We also established an effective electrochemical calendar aging testing protocol to simulate daily usage, enabling quick inference of the calendar life of SSBs. In conclusion, this new testing approach accelerates materials selection strategies for high-nickel NMC composite cathodes in sulfide SSBs.

25 ENERGY STORAGE↗

A laser inverse Compton scattering diagnostic to study runaway electron dynamics during tokamak disruptions

The goal is to design a new diagnostic based on laser inverse Compton scattering (LICS) to study the dynamics of runaway electron formation and their subsequent loss during triggered disruptions in DIII-D. It is known that better measurements of the runaway electron population, throughout the evolution of a disruption, is critical for mitigating the impact of energetic electron beams especially in high plasma current discharges such as those in reactor relevant burning plasmas. The goal of the LICS approach being designed for DIII-D is to measure the timeresolved spatial profile and energy distribution of the runaway electrons while they are in the core of the tokamak plasma. During the last year, a code was developed to simulate the signals from a new laser scattering diagnostic for DIII-D, which will measure the relativistic electron population expected in DIII-D after disruptions triggered by argon pellet injection.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

AB-G0W0: A practical G0W0 method without frequency integration based on an auxiliary boson expansion

Common G0W0 implementations rely on numerical or analytical frequency integration to determine the G0W0 self-energy, which results in a variety of practical complications. Recently, we have demonstrated an exact connection between the G0W0 approximation and equation-of-motion quantum chemistry approaches [J. Tölle and G. Kin-Lic Chan, J. Chem. Phys. 158, 124123 (2023)]. Based on this connection, we propose a new method to determine G0W0 quasiparticle energies, which completely avoids frequency integration and its associated problems. To achieve this, we make use of an auxiliary boson (AB) expansion. We name the new approach AB-G0W0 and demonstrate its practical applicability in a range of molecular problems.

Chemistry↗

Comprehensive Insights into Nucleation, Autocatalytic Growth, and Stripping Efficiency for Lithium Plating in Full Cells

Synchrotron high-energy X-ray diffraction is used to enable nondestructive detection and quantification of heterogeneous lithium plating in working batteries. In this study a LiNi 0.5 Mn 0.3 Co 0.2 O 2 /graphite pouch cell was operated under 6C fast-charge rate for greater than 1200 cycles. The magnitude and spatial distribution of lithium plating, lithium stripping, and the effect of metallic lithium deposition on lithium intercalation into graphite were quantified. Fully intercalated graphite (LiC 6 ) was detected after discharge with a lateral distribution closely correlated with lithium plating, which can be used as a higher-sensitivity indicator for lithium plating. Over an extended cycle life, the overall metallic lithium concentration followed a sigmoidal curve indicating two-stage continuous nucleation and autocatalytic growth. The lithium stripping efficiency underwent an exponential decay as a function of cycle life as the buildup of metallic lithium hindered the efficient dissolution back into the electrolyte. The findings provide direct insights into the characteristics of lithium plating and stripping under realistic fast-charge conditions.

25 ENERGY STORAGE↗

Spatial dynamics of lithiation and lithium plating during high-rate operation of graphite electrodes

The principal inhibitor of fast charging lithium ion cells is the graphite negative electrode, where favorable conditions for lithium plating occur at high charge rates, causing accelerated degradation and safety concerns. The local response of graphite, both at the electrode and particle level, when exposed to fast charging conditions of around 6C is not well understood. Consequently, the conditions that lead to the onset of lithium plating, as well as the local dynamics of lithium plating and stripping, have also remained elusive. Here, we use high-speed (100 Hz) pencil-beam X-ray diffraction to repeatedly raster along the depth of a 101 μm thick graphite electrode in 3 μm steps during fast (up to 6C) charge and discharge conditions. Consecutive depth profiles from separator to current collector were each captured in 0.5 seconds, giving an unprecedented spatial and temporal description of the state of the electrode and graphite's staging dynamics during high rate conditions. The electrode is preferentially activated near the separator, and the non-uniformity increases with rate and is influenced by free-energy barriers between graphite's lithiation stages. The onset of lithium plating and stripping was quantified, occurring only within the first 15 μm from the separator. The presence of lithium plating changed the behavior of the underlying graphite, such as causing co-existence of LiC 6 and graphite in the fully discharged state. Finally, the staging behavior of graphite at different rates was quantified, revealing a high dependency on rate and drastic hysteresis between lithiation and delithiation.

25 ENERGY STORAGE↗