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All sources NASA NTRS DOE OSTI

DOE OSTI2025

A theoretical model for sheath dynamics in the two-plasma mode of a cylindrical filament discharge

We present a refined understanding of cylindrical plasma-facing emitter cathodes by examining the limitations of the conventional space charge limited model, which overlooks ion trapping dynamics within the virtual cathode. While conventional theory distinguishes between temperature-limited and space charge limited regimes based on electron current constraints, our findings reveal that trapped ions can form a quasi-neutral “second plasma,” expanding upstream and interacting with the primary plasma. In cylindrical and other non-planar geometries, an expanding trapped-ions layer produces current enhancement by converting more of the emitted electron flux to passing flux. The current enhancement leads to a complex coupling between the trapped-ions plasma and upstream plasma through ionizing collisions in the upstream region and charge exchange collisions in the virtual cathode. The coupling results in mutual density enhancement and at the same time, antagonistic expansion dynamics between the two plasma layers. The process is understood using a new “aid-compete” model. Numerical solutions, validated against simulations, reveal the model's capacity to predict system evolution and complex discharge behaviors, albeit with qualitative approximations.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2020

Interlayer gap widened $α$-phase molybdenum trioxide as high-rate anodes for dual-ion-intercalation energy storage devices

Employing high-rate ion-intercalation electrodes represents a feasible way to mitigate the inherent trade-off between energy density and power density for electrochemical energy storage devices, but efficient approaches to boost the charge-storage kinetics of electrodes are still needed. Here, we demonstrate a water-incorporation strategy to expand the interlayer gap of α-MoO 3 , in which water molecules take the place of lattice oxygen of α-MoO 3 . Accordingly, the modified α-MoO 3 electrode exhibits theoretical-value-close specific capacity (963 C g –1 at 0.1 mV s –1 ), greatly improved rate capability (from 4.4% to 40.2% at 100 mV s –1 ) and boosted cycling stability (from 21 to 71% over 600 cycles). A fast-kinetics dual-ion-intercalation energy storage device is further assembled by combining the modified α-MoO 3 anode with an anion-intercalation graphite cathode, operating well over a wide discharge rate range. Our study sheds light on a promising design strategy of layered materials for high-kinetics charge storage.

25 ENERGY STORAGE↗

DOE OSTI2026

Ionic liquid-enhanced recycling of lithium-ion battery black mass via heavy liquid centrifugal separation

Direct recycling of lithium-ion batteries (LIBs) is of great significance to supply chain security and environmental protection by restoring spent battery materials to their original purpose without destroying their chemical structure. One of the key processes for direct recycling is to separate valuable anode and cathode active materials from black mass. This study evaluates ionic liquid-enhanced Heavy Liquid Centrifugal Separation (HLCS) as an efficient method for separating LIB black mass into its constituent anode and cathode materials. The optimized HLCS process achieved a separation efficiency of over 95%, yielding a graphite-rich upper layer and an NMC-rich lower layer. Characterization by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and inductively coupled plasma-optical emission spectroscopy (ICP-OES) confirmed the purity and structural integrity of the recovered fractions. The addition of N-methyl-2-pyrrolidone and ionic liquid 1-ethyl-3-methylimidazolium bromide decoupled entangled particles, while subsequent treatment of the anode layer with 1-(2,3-dihydroxypropyl)-3-methylimidazolium chloride further enhanced separation purity. The recycled graphite exhibited comparable battery performance to pristine graphite. These results demonstrate HLCS as a promising LIB recycling strategy, advancing sustainable battery manufacturing.

Adigun, Babafemi [Univ. of Tennessee, Knoxville, T↗

DOE OSTI2020

Micro-Tubular Solid Oxide Fuel Cell Polarization and Impedance Variation With Thin Porous Samarium-Doped Ceria and Gadolinium-Doped Ceria Buffer Layer Thickness

Abstract Porous buffer layers for anode-supported solid oxide fuel cells (SOFCs) have been investigated for many years with different thicknesses of the buffer layer in each study. In this work, micro-tubular SOFCs having samarium-doped ceria (SDC) and gadolinium-doped ceria (GDC) buffer layers are compared using the current–voltage technique, electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The thickness of the porous SDC and GDC buffer layer is investigated systematically with the thickness varying between 0.3 and 2.0 μm. The power density varies between 212 and 1004 mW/cm2 for samples having different SDC buffer layer thickness. Comparable changes occur for the SOFCs with a GDC buffer layer, but less variation in polarization losses resulted. Variation in electrochemical performance varies due to changes in ohmic resistance, cathode activation polarization, and interfacial reactions between the cathode and electrolyte materials.

Electrochemistry↗

NASA NTRS1982

Application of Organic Solid Electrolytes

If ions are considered to be solid material which transport electric charges, polymer materials can then be considered as organic solid electrolytes. The role of these electrolytes is discussed for (1) ion concentration sensors; (2) batteries using lithium as the cathode and a charge complex of organic material and iodine in the anode; and (3) elements applying electrical double layer capability.

Sekido, S.↗

NASA NTRS1987

Electrodeposition of metals and metal/cermet composites in low gravity

Electrodeposition experiments were carried out on the bench and a KC-135 aircraft at 0.01 g in anticipation of microgravity flights on NASA's Space Transportation System Shuttle. Experimental results obtained by interferometry compare concentration gradients as a function of time in the vicinity of a reducing electrode (cathode) for Cu(+2) and Co(+2) electrodeposition cells. No difference was found between bench and 0.01 g produced gradients for a .1M CuSO4 cell, but a significant difference was noted between the gradients in a 1M CoSO4 cell even though the bench cells were operated in a nonconvecting shielded (cathode over anode) mode. The gradient for Co(+2) depletion produced at 0.01 g was greater and the entire layer was thicker than found on the bench. Neutral buoyancy/matched density codeposition experiments were performed on the bench in an attempt to physically duplicate the results of metal/cermet codepositions in microgravity. Polystyrene spheres with average diameter 11.8 microns and density approximately matching that of 1M CoSO4 were utilized to emulate nonsedimenting cermets in microgravity. The cells were operated in a shielded convectionless mode. Comparison with literature data on codeposition with stirred cells indicate significant improvement in volume percent neutral occluded in the depositing metal matrix. A multicell electrodeposition flight apparatus that has been designed, constructed and is undergoing testing is discussed.

Riley, Clyde↗

DOE OSTI2020

System and method for work function reduction and thermionic energy conversion

A thermionic energy converter, preferably including an anode and a cathode. An anode of a thermionic energy converter, preferably including an n-type semiconductor, one or more supplemental layers, and an electrical contact. A method for work function reduction and/or thermionic energy conversion, preferably including inputting thermal energy to a thermionic energy converter, illuminating an anode of the thermionic energy converter, thereby preferably reducing a work function of the anode, and extracting electrical power from the system.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2023

System and method for work function reduction and thermionic energy conversion

Schwede, Jared William↗

DOE OSTI2021

Minimizing Cr-Evaporation from Balance of Plant Components by Utilizing Cost-Effective Alumina-Forming Austenitic Steels

A solid oxide fuel cell (SOFC) is a clean and efficient energy conversion device. The development of intermediate-temperature SOFCs has made it preferable to use metallic interconnects (MICs) to greatly reduce the cost and significantly increase the efficiency compared to ceramic interconnect materials. However, gaseous chromium species will evaporate from the chromium-containing layer formed on the surface of commonly used MICs and balance of plant (BoP) components. Volatile chromium species have been shown to form solid deposits which poison the cathodes of SOFCs, causing drastic cell performance degradation and thereby limiting commercialization. In order to alleviate the Cr poisoning and achieve long-term high performance of SOFC stacks, various Al2O3-forming austenitic (AFA) stainless steels applied at different temperatures are evaluated in this project. Based on our Phase I results (500 h operation), it is shown that on the AFAs, an alumina-based protective layer forms under high temperature that is invulnerable to water vapor effects and suppresses the diffusion of chromium and manganese which can prevent the generation of spinels on the alloy surface. Therefore, 310S, OC4 and OC5 at 800 °C and 625, OC11 and OC11LZ at 900 °C are selected to be tested in the Phase II long-term operation. From the results, we find that besides the lower Cr evaporation rates and better oxidation resistance of AFAs than benchmark alloys after short-term (500 h) operation, AFAs also possess the sturdy and compact alumina layer after a long-term operation (5000 h). A protective oxide layer is of great importance for the long-term high-temperature operation of structural materials. The high-temperature oxidation behavior of AFAs and commercial 310S and 625 alloys in Air + 10% H 2 O at 800 °C and 900 °C is systematically investigated. Severe breakaway oxidation and minor spallation are observed for the 310S and 625 after the long-term operation, while the AFAs show high oxidation resistance. It is found that the formation of a continuous alumina layer could greatly prevent the volatilization of chromium vapors. In addition, the corresponding evolving models are discussed. Chromium evaporation from BoP components in high-temperature environment could severely deteriorate the electrochemical performance of SOFC. Several methods were applied to evaluate the Cr evaporation rates of BoP after 500 h exposure at 800 °C to 900 °C in air with 10% H 2 O. An optimal method was designed to exclude the effect of silicon (Si) deposits from quartz tube and sodium (Na) deposits from the sodium carbonate on the oxidation process and the chemical interaction between Cr gaseous species and alumina tube which could provide further quantitative correlation of the evaporated Cr species quantities and degradation rates of SOFC. Based on the great performance of AFAs after long-term operation, AFAs are assembled with Anode-supported cells (ASC) to investigate the the Cr deposition of anode-supported cell under a constant current density of 0.5 A cm -2 at 800 °C with AFA alloys compared with commercial alloys. In addition, the anodic and cathodic processes are deconvoluted by distribution of relaxation times (DRT) method which are comprehensively discussed. It is found out that the voltage exhibited a slight decrease of 5.09 % and 1.54 % in the presence of OC11 and OC11LZA alloy, respectively. However, a considerable decrease of 22.14 % and 12.06 % was determined in the presence of 310S and 625 alloy, respectively. AFAs possessing the low-cost, low Cr evaporation rates and the high oxidation resistance will make it of great potential to replace the existing BoP components.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Anode‐Free Lithium–Sulfur Cells Enabled by Rationally Tuning Lithium Polysulfide Molecules

Abstract The two major barriers of practical lithium–sulfur batteries are the poor reversibility of lithium‐metal anode and sluggish kinetics of sulfur cathode. Here, we report a simple yet cogent, molecular tailoring approach for lithium polysulfides, enabling a synergistic enhancement of anode reversibility and cathode kinetics. We show that SnI 4 coordinates with lithium polysulfides to form soluble complexes, resulting in a Li 2 SnS 3 ‐rich anode interphase layer. As Li 2 SnS 3 is stable against parasitic reactions and has a lower ionic resistance over cycling, the Li plating/stripping efficiency is greatly improved. In addition, the formation of soluble complexes between SnI 4 and lithium polysulfides play a non‐negligible role in suppressing the clustering behavior of lithium polysulfide molecules, resulting in a significant enhancement in sulfur conversion kinetics under lean electrolyte conditions. The synergistic improvement is validated in anode‐free, lean‐electrolyte pouch cells with a Li 2 S cathode that displays capacity retention of 78 % after 100 cycles.

Ren, Yuxun↗

DOE OSTI2021

Minimizing Cr-Evaporation from Balance Of Plant Components By Utilizing Cost-Effective Alumina-Forming Austenitic Steels

A solid oxide fuel cell (SOFC) is a clean and efficient energy conversion device. The development of intermediate-temperature SOFCs has made it preferable to use metallic interconnects (MICs) to greatly reduce the cost and significantly increase the efficiency compared to ceramic interconnect materials. However, gaseous chromium species will evaporate from the chromium-containing layer formed on the surface of commonly used MICs and balance of plant (BoP) components. Volatile chromium species have been shown to form solid deposits which poison the cathodes of SOFCs, causing drastic cell performance degradation and thereby limiting commercialization. In order to alleviate the Cr poisoning and achieve long-term high performance of SOFC stacks, various Al 2 O 3 -forming austenitic (AFA) stainless steels applied at different temperatures are evaluated in this project. Based on our Phase I results (500 h operation), it is shown that on the AFAs, an alumina-based protective layer forms under high temperature that is invulnerable to water vapor effects and suppresses the diffusion of chromium and manganese which can prevent the generation of spinels on the alloy surface. Therefore, 310S, OC4 and OC5 at 800 °C and 625, OC11 and OC11LZ at 900 °C are selected to be tested in the Phase II long-term operation. From the results, we find that besides the lower Cr evaporation rates and better oxidation resistance of AFAs than benchmark alloys after short-term (500 h) operation, AFAs also possess the sturdy and compact alumina layer after a long-term operation (5000 h). A protective oxide layer is of great importance for the long-term high-temperature operation of structural materials. The high-temperature oxidation behavior of AFAs and commercial 310S and 625 alloys in Air + 10% H 2 O at 800 °C and 900 °C is systematically investigated. Severe breakaway oxidation and minor spallation are observed for the 310S and 625 after the long-term operation, while the AFAs show high oxidation resistance. It is found that the formation of a continuous alumina layer could greatly prevent the volatilization of chromium vapors. In addition, the corresponding evolving models are discussed. Chromium evaporation from BoP components in high-temperature environment could severely deteriorate the electrochemical performance of SOFC. Several methods were applied to evaluate the Cr evaporation rates of BoP after 500 h exposure at 800 °C to 900 °C in air with 10% H 2 O. An optimal method was designed to exclude the effect of silicon (Si) deposits from quartz tube and sodium (Na) deposits from the sodium carbonate on the oxidation process and the chemical interaction between Cr gaseous species and alumina tube which could provide further quantitative correlation of the evaporated Cr species quantities and degradation rates of SOFC. Based on the great performance of AFAs after long-term operation, AFAs are assembled with Anode-supported cells (ASC) to investigate the the Cr deposition of anode-supported cell under a constant current density of 0.5 A cm -2 at 800 °C with AFA alloys compared with commercial alloys. In addition, the anodic and cathodic processes are deconvoluted by distribution of relaxation times (DRT) method which are comprehensively discussed. It is found out that the voltage exhibited a slight decrease of 5.09 % and 1.54 % in the presence of OC11 and OC11LZA alloy, respectively. However, a considerable decrease of 22.14 % and 12.06 % was determined in the presence of 310S and 625 alloy, respectively. AFAs possessing the low-cost, low Cr evaporation rates and the high oxidation resistance will make it of great potential to replace the existing BoP components.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2023

Fundamentals of SrCoO 3-δ Based Oxygen Deficient Perovskites as Cathodes for Solid Oxide Fuel Cells

The local structure and oxygen stoichiometry in oxide systems have a profound impact on oxygen electrocatalysis encountered in metal-air batteries and solid oxide fuel cells (SOFCs). However, this knowledge is often obtained under conditions different from the real working conditions of the material, resulting in misinterpretation and misunderstanding. This PhD dissertation aims to obtain the structure and oxygen-stoichiometry information of a class of perovskite oxides under their real working conditions in solid oxide fuel cells. Several perovskite oxides were selected for the study: Sr 0.9 Y 0.1 CoO 3-δ (SYC10), Sr 0.9 Y 0.3 CoO 3-δ (SYC30), SrCo 0.9 Nb 0.1 O 3-δ (SCN10) and SrCo 0.9 Ta0.1O 3-δ (SCT10). The local crystal structure and oxygen stoichiometry of these materials were systematically characterized with in-situ neutron diffraction (ND). The oxygen stoichiometry was also measured by thermogravimetric analysis (TGA) and iodometric titration methods. To establish the correlation among structure, oxygen stoichiometry and oxygen reduction reaction (ORR) activity, high temperature electrochemical impedance spectroscopy, oxygen permeation and single cell testing were also performed. In chapter 2, SYC10 is described to have a more symmetrical structure and $V_o^{··}$ distribution, and higher $V_o^{··}$ concentration than SYC30. Molecular orbital energy analysis based on the local structure of the ORR-active Co1-polyhedra indicates SYC30 has a higher Fermi level relative to O-2p energy level in the active Co1-polyhedra, and thus a higher motional enthalpy for $V_o^{··}$ migration. However, the ORR activity of Y-doped SrCoO 3-δ (SCO) are found uncompetitive with other popular catalysts. In chapter 3 and 4, systematic structural studies are presented for Nb and Ta-doped SCO, namely SCN10 and SCT10, respectively. The methodology of unrevealing the structure-activity relationships in chapter 2 is also found applicable to SYC10, SCN10 and SCT10 as presented in chapter 5. The electrochemical tests indicate that SCT10 is the best catalyst due to its excellent thermal and electrochemical stability. In chapter 6, SCT10 is evaluated in a real solid oxide fuel cell in the form of nanoscaled SCT10 layer coating on the commercial (La 0.6 Sr 0.4 ) 0.95 Co 0.2 Fe 0.8 O 3-δ (LSCF). The bilayer structured cathode shows excellent properties of coarsening-resistant, Sr-segregation-free and high ORR-activity.

Yang, Tianrang↗

DOE OSTI2026

All‐Solid‐State Batteries With Mechanically Stable Interfaces Consisting of a Zero‐Strain Cation‐Disordered Rocksalt Cathode

Interface stabilization is critical to the development of working all‐solid‐state batteries. Rigid cathode/solid electrolyte interfaces often disintegrate due to anisotropic volume change of cathode‐active materials, resulting in irreversible capacity loss. Herein, we demonstrate that Li 1.211 Mo 0.467 Cr 0.3 O 2 (LMCO), a pioneering cation‐disordered rocksalt oxide (DRX) cathode that has intrinsically small volume change upon lithium intercalation, can be integrated with a thiophosphate‐based solid electrolyte for all‐solid‐state batteries. Interface stability of the all‐solid LMCO cell was investigated by electrochemical impedance spectroscopy, X‐ray micro‐computed tomography, and electron microscopy. Since LMCO was initially synthesized as a layered phase exhibiting a large volume change, interface disintegration can be observable in the early cycles. As layered LMCO phase‐transformed into DRX LMCO in subsequent cycles, reintegration of the interfaces occurs within a pressurized cell as a result of its zero‐stain behavior. Consequently, the DRX LMCO cathode maintains interface integrity, and thus electrical wiring, over an extended number of cycles, leading to improved capacity retention with small internal cell resistance.

DRX↗

DOE OSTI2022

High Energy Aqueous Lithium-Ion Batteries (Final Report)

Lithium-ion batteries (LIBs) are a widely used energy storage device. For decades, researchers have been studying aqueous electrolytes due to their non-flammability and environmental friendless. However, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of water greatly limit the voltage window of the aqueous electrolyte. The recent concept of ‘solvent-in-salt’ electrolytes, namely ‘water-in-salt’ electrolytes (WISE) for aqueous batteries and ‘super-concentrated’ electrolytes for non-aqueous batteries, greatly expands the electrochemical window of these battery systems and consequently their energy density. This expansion occurs because the large number of salt aggregates in ‘solvent-in-salt’ electrolytes enables preferential salt decomposition over solvent decomposition to form robust interphase layers on electrodes, thus enhancing their stability in a wide range of operating voltages. However, even when the salt concentration reached 63m, regardless of cost, the cathodic potential of the WISE expanded only to 1.75V with an overall electrochemical stability window of <3.25V. To design the next generation of high energy aqueous LIBs, electrolytes that possess a wider electrochemical stability window and lower cost but still maintain the merit of non-flammability are much needed. In this project, we designed the aqueous LIBs with widened voltage window. We reported a cheap and non-flammable ternary eutectic electrolyte that can form a robust solid electrolyte interface (SEI)so that the cathodic limiting potential can be decreased to <1.5 V for Li 4 Ti 5 O 12 anodes, while maintaining both a high ionic conductivity of >10 -3 S cm –1 and a low viscosity. We demonstrated the super-stable2.5V LiMn 2 O 4 ||Li 4 Ti 5 O 12 pouch cell with mass loading of 2.5 mAh/cm. Further, LiCl-LiBr-Graphite/Li full cells were designed with high energy density. Finally, we use a bi-layer design to enlarge the voltage window of aqueous electrolyte, which can endow the stable cycling of aqueous Lithium metal batteries.

25 ENERGY STORAGE↗

DOE OSTI2025

Pristine Interface between Lithium Lanthanum Zirconate and Lithium Manganese Oxide by Pulsed Laser Deposition

Solid state lithium-ion batteries have garnered increasing interest in recent years due to several potential advantages over liquid-electrolyte based systems. The possibility of integrating the lithium garnet oxide, Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO), with the high voltage cathode, spinel Li x Mn 2 O 4 (LMO), is evaluated here. Thin film bilayer structures are prepared by pulsed laser deposition on MgO (001) substrates and characterized by x-ray diffraction and transmission electron microscopy. The LLZTO is grown by an alternating layer-by-layer deposition of LLZTO and Li 3 N and subsequently annealed for several hours at 575 °C to promote crystallinity. Growth of crystalline LMO with a pristine interface to LLZTO is achieved by gentle heat treatment (500 °C) to remove surface carbonate from the electrolyte and by cathode growth at a low temperature of 250 °C. Higher temperature depositions (330 – 450 °C) result in reaction between the two materials and the appearance of Li 2 MnO 3 , which may be in part due to the presence of excess lithium in the electrolyte layer. Because fully lithiated LiMn 2 O 4 has a voltage of ≈3.7 V versus Li+/Li, the observation of a well-defined interface, free of impurity phases and with no interdiffusion of elements, indicates LLZTO is stable to at least 3.7 V.

Garnet LLZO↗

DOE OSTI2020

Fully Exploited Oxygen Redox Reaction by the Inter-Diffused Cations in Co-Free Li-Rich Materials for High Performance Li-Ion Batteries

To meet the growing demand for global electrical energy storage, high-energy-density electrode materials are required for Li-ion batteries. To overcome the limit of the theoretical energy density in conventional electrode materials based solely on the transition metal redox reaction, the oxygen redox reaction in electrode materials has become an essential component because it can further increase the energy density by providing additional available electrons. However, the increase in the contribution of the oxygen redox reaction in a material is still limited due to the lack of understanding its controlled parameters. Here, it is first proposed that Li-transition metals (TMs) inter-diffusion between the phases in Li-rich materials can be a key parameter for controlling the oxygen redox reaction in Li-rich materials. The resulting Li-rich materials can achieve fully exploited oxygen redox reaction and thereby can deliver the highest reversible capacity leading to the highest energy density, ≈1100 Wh kg -1 among Co-free Li-rich materials. The strategy of controlling Li/transition metals (TMs) inter-diffusion between the phases in Li-rich materials will provide feasible way for further achieving high-energy-density electrode materials via enhancing the oxygen redox reaction for high-performance Li-ion batteries.

25 ENERGY STORAGE↗

DOE OSTI2022

Precision surface modification of solid oxide fuel cells via layer-by-layer surface sol–gel deposition

While solid oxide fuel cells (SOFCs) are a promising technology for a clean and sustainable future, their commercialization is hindered by limited durability and performance. Here, we report our findings on the application of a layer-by-layer surface sol–gel (SSG) coating of catalysts to dramatically enhance the electro-catalytic activity and durability of SOFC cathodes. The SSG process is capable of penetrating and preserving complex backbone microstructures of porous electrodes, creating highly conformal coatings of controlled morphology, while tailoring the composition of the surface to improve catalytic properties and durability. For example, the application of an SSG coating of PrO x to a La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3–δ (LSCF) cathode has reduced the polarization resistance from 1.136 to 0.117 Ω cm 2 at 600 °C and the degradation rate from 1.13 × 10 –3 to 2.67 × 10 –4 Ω cm 2 h –1 at 650 °C. In addition, a continuous improvement in electrode performance is demonstrated as the thickness of the coating is increased, corresponding to the linear addition of catalyst. Furthermore, this first application of the SSG technique to SOFC systems opens the door for the controlled surface modification of porous components in electrochemical systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Structural regulation-induced Li-electron disentanglement for stabilized oxygen redox of Li-excess disordered rock-salt cathode materials

Since the discovery of its electrochemical activity, Li-excess disordered rock-salt (DRX) cathode material has received worldwide attention as it sets up a new way to exploit oxygen redox beyond the conventional layered structure with late-3d transition metals. However, the intricate structure-function relationship in the disordered lattice of the DRX material fogs the researcher's lens on the underlying redox mechanisms. Here, in this study, we employ a synergistic approach combining neutron total scattering with reverse Monte Carlo modeling and density functional theory calculations to unravel the landscape of oxygen redox reactions in DRX. Redox activities are evaluated in diverse oxygen clusters (OLi x TM 6-x ) and the spatial distribution of these clusters in the model DRX structure (Li 1.16 Ti 0.37 Ni 0.37 Nb 0.1 O 2 and Li 1.2 Ti 0.35 Ni 0.35 Nb 0.1 O 1.8 F 0.2 ) is explicitly determined. The results unveil that by regulating the short-range ordering between cations, fluorine atoms can effectively decouple the location of Li extraction and electron depletion. Such disentanglement between the Li reservoir and electron reservoir in the DRX lattice could play a pivotal role in protecting the oxidized oxygen and preserving the lattice framework during cycling. Through a tentatively designed non-fluorinated DRX oxide realizing similar Li-electron decoupling, an obvious enhancement of the cycling capability can be achieved without compromising the capacity release.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗