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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Mg(Hg11N3)2 by Materials Project

Mg(Hg11N3)2 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Mg is bonded in a square co-planar geometry to four equivalent N atoms. All Mg–N bond lengths are 2.13 Å. There are five inequivalent Hg sites. In the first Hg site, Hg is bonded in a single-bond geometry to one Hg and one N atom. The Hg–Hg bond length is 2.71 Å. The Hg–N bond length is 2.20 Å. In the second Hg site, Hg is bonded in a single-bond geometry to one Hg and one N atom. The Hg–Hg bond length is 2.98 Å. The Hg–N bond length is 2.14 Å. In the third Hg site, Hg is bonded in a single-bond geometry to two Hg and one N atom. There are one shorter (3.10 Å) and one longer (3.27 Å) Hg–Hg bond lengths. The Hg–N bond length is 2.46 Å. In the fourth Hg site, Hg is bonded in a 9-coordinate geometry to nine Hg atoms. In the fifth Hg site, Hg is bonded in a 4-coordinate geometry to four equivalent Hg atoms. There are two inequivalent N sites. In the first N site, N is bonded in a distorted trigonal bipyramidal geometry to five Hg atoms. In the second N site, N is bonded in a trigonal planar geometry to one Mg and two equivalent Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(ScS2)2 by Materials Project

Mg(ScS2)2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one Mg(ScS2)2 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent ScS6 octahedra, and corners with six ScS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are one shorter (2.43 Å) and three longer (2.46 Å) Mg–S bond lengths. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share a cornercorner with one MgS4 tetrahedra, corners with five ScS4 tetrahedra, edges with two equivalent MgS6 octahedra, and edges with four equivalent ScS6 octahedra. There are a spread of Mg–S bond distances ranging from 2.64–2.70 Å. There are four inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to four S2- atoms to form ScS4 tetrahedra that share a cornercorner with one ScS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four ScS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Sc–S bond distances ranging from 2.42–2.47 Å. In the second Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share corners with two equivalent MgS4 tetrahedra, corners with four ScS4 tetrahedra, edges with two equivalent ScS6 octahedra, and edges with four equivalent MgS6 octahedra. There are a spread of Sc–S bond distances ranging from 2.58–2.68 Å. In the third Sc3+ site, Sc3+ is bonded to four S2- atoms to form ScS4 tetrahedra that share a cornercorner with one ScS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four ScS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of Sc–S bond distances ranging from 2.42–2.48 Å. In the fourth Sc3+ site, Sc3+ is bonded to four S2- atoms to form ScS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent ScS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four ScS4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. There are a spread of Sc–S bond distances ranging from 2.43–2.47 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Mg2+ and two Sc3+ atoms to form distorted SMg2Sc2 trigonal pyramids that share corners with five SMg2Sc2 tetrahedra, corners with four equivalent SMgSc3 trigonal pyramids, edges with two SMg2Sc2 tetrahedra, and an edgeedge with one SMg2Sc2 trigonal pyramid. In the second S2- site, S2- is bonded to two Mg2+ and two equivalent Sc3+ atoms to form distorted SMg2Sc2 tetrahedra that share corners with four equivalent SMg2Sc2 tetrahedra, corners with five SMg2Sc2 trigonal pyramids, an edgeedge with one SMg2Sc2 tetrahedra, and edges with two SMgSc3 trigonal pyramids. In the third S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Sc3+ atoms. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Sc3+ atoms. In the fifth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Sc3+ atoms. In the sixth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Sc3+ atoms. In the seventh S2- site, S2- is bonded to one Mg2+ and three Sc3+ atoms to form distorted SMgSc3 trigonal pyramids that share corners with five SMg2Sc2 tetrahedra, corners with four equivalent SMg2Sc2 trigonal pyramids, edges with two SMg2Sc2 tetrahedra, and an edgeedge with one SMgSc3 trigonal pyramid. In the eighth S2- site, S2- is bonded to two equivalent Mg2+ and two Sc3+ atoms to form distorted SMg2Sc2 tetrahedra that share corners with four equivalent SMg2Sc2 tetrahedra, corners with five SMg2Sc2 trigonal pyramids, an edgeedge with one SMg2Sc2 tetrahedra, and edges with two SMgSc3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(AlSb)2 by Materials Project

Mg(AlSb)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Mg is bonded to six equivalent Sb atoms to form MgSb6 octahedra that share corners with twelve equivalent AlSb4 tetrahedra, edges with six equivalent MgSb6 octahedra, and edges with six equivalent AlSb4 tetrahedra. All Mg–Sb bond lengths are 3.12 Å. Al is bonded to four equivalent Sb atoms to form AlSb4 tetrahedra that share corners with six equivalent MgSb6 octahedra, corners with six equivalent AlSb4 tetrahedra, edges with three equivalent MgSb6 octahedra, and edges with three equivalent AlSb4 tetrahedra. The corner-sharing octahedra tilt angles range from 11–58°. There are one shorter (2.83 Å) and three longer (2.84 Å) Al–Sb bond lengths. Sb is bonded to three equivalent Mg and four equivalent Al atoms to form a mixture of distorted edge and corner-sharing SbMg3Al4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(BH4)2 by Materials Project

Mg(BH4)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional and consists of two Mg(BH4)2 frameworks. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to twelve equivalent H+0.50+ atoms to form distorted MgH12 cuboctahedra that share faces with four equivalent BH4 tetrahedra. All Mg–H bond lengths are 2.30 Å. In the second Mg2+ site, Mg2+ is bonded to four equivalent H+0.50+ atoms to form MgH4 tetrahedra that share corners with four equivalent BH4 tetrahedra. All Mg–H bond lengths are 1.80 Å. B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share a cornercorner with one MgH4 tetrahedra and a faceface with one MgH12 cuboctahedra. There is three shorter (1.22 Å) and one longer (1.24 Å) B–H bond length. There are two inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a linear geometry to one Mg2+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one Mg2+ and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(IN)2 by Materials Project

Mg(NI)2 crystallizes in the orthorhombic Pbam space group. The structure is one-dimensional and consists of two Mg(NI)2 ribbons oriented in the (1, 0, 0) direction. Mg2+ is bonded to two equivalent N and four equivalent I1- atoms to form edge-sharing MgI4N2 octahedra. Both Mg–N bond lengths are 2.25 Å. All Mg–I bond lengths are 2.86 Å. N is bonded in a single-bond geometry to one Mg2+ atom. I1- is bonded in an L-shaped geometry to two equivalent Mg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Experimental characterization and atomistic simulation of grain boundary segregation in Mg-Y alloys

As a rare earth solute element in Mg alloys, Y has the beneficial effects of increasing both the strength and the ductility as well as weakening the crystallographic texture. To achieve a more fundamental understanding on how Y addition affects the microstructural evolution and mechanical properties, the Y segregation behavior at grain boundaries was investigated in Mg-1wt.%Y and Mg-7wt.%Y alloys at different conditions. The segregation intensity and its dependence on the grain boundary misorientation angle were experimentally characterized and computationally predicted. Strong segregation at grain boundaries was observed in both low and high Y-containing alloys. Y segregation was found to remain in alloy Mg-7Y after high-temperature annealing heat treatment at 540 °C. No direct correlation between the Y segregation intensity and the grain boundary misorientation angle could be established based on either the experimental characterization or the atomistic simulation with a spectral model. We thus conclude that grain boundary segregation of Y is independent of grain boundary misorientation angle.

Grain boundary↗
DOE OSTI2025

Effect of Mg and Ni impurities on tritium diffusion in lithium ceramics through cluster dynamics simulations

This study investigates the impact of Mg and Ni doping on tritium diffusion in LiAlO 2 and LiAl 5 O 8 ceramics, that are used in tritium-producing burnable absorber rods (TPBARs). Utilizing Centipede simulations across a broad temperature range (500 K to 1250 K), we explore the interplay between defect dynamics, cluster formation, and tritium mobility. In LiAlO 2 , Mg doping significantly enhances tritium diffusivity by increasing tritium interstitial concentrations and diffusion coefficients of key species, thereby doubling the overall tritium diffusivity. Ni doping, while shifting the dominant defect to Li vacancies, maintains high tritium mobility due to the low binding energy of Li vacancy-tritium complexes, which ensures effective tritium migration. In LiAl 5 O 8 , Mg and Ni doping results in a slight reduction in the diffusion coefficients of key species, yet the dramatic increase in tritium interstitial concentrations compensates, leading to a net small increase in tritium diffusivity. In conclusion, the findings highlight the critical role of defects in tritium transport and the effect of Mg and Ni defects on the performance of these ceramics in demanding nuclear environments.

Cluster dynamics↗
DOE OSTI2024

Coexistence and Interplay of Two Ferroelectric Mechanisms in Zn 1-x Mg x O

Ferroelectric materials promise exceptional attributes including low power dissipation, fast operational speeds, enhanced endurance, and superior retention to revolutionize information technology. However, the practical application of ferroelectric-semiconductor memory devices has been significantly challenged by the incompatibility of traditional perovskite oxide ferroelectrics with metal-oxide-semiconductor technology. Recent discoveries of ferroelectricity in binary oxides such as Zn 1-x Mg x O and Hf 1-x Zr x O have been a focal point of research in ferroelectric information technology. Here, this work investigates the ferroelectric properties of Zn 1-x Mg x O utilizing automated band excitation piezoresponse force microscopy. This findings reveal the coexistence of two ferroelectric subsystems within Zn 1-x Mg x O. A “fringing-ridge mechanism” of polarization switching is proposed that is characterized by initial lateral expansion of nucleation without significant propagation in depth, contradicting the conventional domain growth process observed in ferroelectrics. This unique polarization dynamics in Zn 1-x Mg x O suggests a new understanding of ferroelectric behavior, contributing to both the fundamental science of ferroelectrics and their application in information technology.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Polarity‐Driven Atomic Displacements at the 2D Mg 2 TiO 4 ‐MgO (001) Oxide Interface for Hosting Potential Interlayer Excitons

Abstract Interlayer excitons in solid‐state systems have emerged as candidates for realizing novel platforms ranging from excitonic transistors and optical qubits to exciton condensates. Interlayer excitons have been discovered in 2D transition metal dichalcogenides, with large exciton binding energies and the ability to form various van der Waals heterostructures. Here, an oxide system consisting of a single unit cell of Mg 2 TiO 4 on MgO (001) is proposed as a platform for hosting interlayer excitons. Using a combination of density functional theory (DFT) calculations, molecular beam epitaxy growth, and in situ crystal truncation rod measurements, it is shown that the Mg 2 TiO 4 ‐MgO interface can be precisely controlled to yield an internal electric field suitable for hosting interlayer excitons. The atoms in the polar Mg 2 TiO 4 layers are observed to be displaced to reduce polarity at the interface with the non‐polar MgO (001) surface. Such polarity‐driven atomic displacements strongly affect electrostatics of the film and the interface, resulting in localization of filled and empty band‐edge states in different layers of the Mg 2 TiO 4 film. The DFT calculations suggest that the electronic structure is favorable for localization of photoexcited electrons in the bottom layer and holes in the top layer, which may bind to form interlayer exciton states.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Fast Room-Temperature Mg-Ion Conduction in Clay-Like Halide Glassy Electrolytes

The discovery of mechanically soft solid-state materials with fast Mg-ion conduction is crucial for the development of solid-state magnesium batteries. In this paper, novel magnesium gallium halide compounds are reported that achieve high ionic conductivity of 0.47 mS cm -1 at room temperature. These Mg-ion conductors obtained by ball milling Mg and Ga salts exhibit clay-like mechanical properties, enabling intimate contact at the electrode–electrolyte interface during battery cycling. With a combination of experimental and computational analysis, this study identifies that the soft-clay formation is induced by partial anion exchange during milling. This partial anion exchange creates undercoordinated magnesium ions in a chlorine-rich environment, yielding fast Mg-ion conduction. This work demonstrates the potential of clay-like halide electrolytes for all-solid-state magnesium batteries, with possible further extension to other multivalent battery systems.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Improvement of Drop‐Hammer Impact Testing for Safety Assessment of High Explosives Using 10‐mg Samples

Here, in this study, we established an improved method for drop-hammer impact testing of small quantities of high explosives (10 mg). We performed about seven hundred impact tests under various experimental conditions (e.g., sandpaper vs bare anvil, different sample masses, drop-weights, and striker diameters) to determine an optimal set of conditions and reaction detection methods (e.g., gas analysis, video, and sound recordings) that give the most statistically reliable results with 10 mg samples. We used both Frequentist and Bayesian statistical approaches to compare estimates of the drop height (DH50) that initiates a reaction 50% of the time, and to quantify the associated uncertainty. Gas analysis proved to be the most reliable reaction detection method, showing unambiguous rises in HE decomposition products (e.g., CO 2 ) even when the other indicators (e.g., sound, video) were inconclusive. The impact tests performed with a bare anvil showed much better reproducibility than those conducted with sandpaper, reducing the largest uncertainty observed in the data sets by a factor of 1.7. The DH 50 values obtained from three different sample masses (10, 20, and 35 mg) fell within the uncertainties of the measurements. We demonstrated the improved procedure (i.e., 10-mg samples, gas analysis, bare anvil, and Bayesian approach) on a variety of PETN samples having different surface areas and thermal histories.

PETN↗
DOE OSTI2025

Characterization of Recrystallized Grains During Static Recrystallization of Hot-Compressed Mg–Zn–Ca Alloys Using In Situ Far-Field High-Energy Diffraction Microscopy

In this study, we explored the effect of Zn content on the static recrystallization of three 80 pct hot-compressed alloys, Mg–0.5Zn–0.1Ca wt pct (ZX050), Mg–1Zn–0.1Ca wt pct (ZX10), and Mg–3.2Zn–0.1Ca wt pct (ZX30), using far-field high-energy microscopy (ff-HEDM). Individual recrystallized grains were tracked and their 3D centroid, relative volume, and grain-averaged crystallographic orientation were measured during annealing. These measurements were used to compare the recrystallization kinetics and texture evolution of recrystallized grains in ZX alloys as a function of the Zn content. Fully recrystallized microstructures were observed for the ZX30 and the ZX10 alloys after annealing at 230 °C and 330 °C, respectively. In contrast, only a partially recrystallized microstructure for the ZX050 alloy was observed after > 1 hour of annealing at 430 °C. The resistance to recrystallization with decreasing Zn content was also confirmed by detecting faster growth rates of recrystallized grains in the ZX10 and ZX30 alloys, and slower growth rates in the ZX050 alloy. The significant recrystallization texture weakening of the ZX10 and ZX30 alloys and the development of a basal texture in the ZX05 alloy were described based on the orientation dependency of nucleation and growth of recrystallized grains. The analysis demonstrated that texture weakening was associated with increasing Zn content in Mg–Zn–Ca alloys.

Roumina, Reza [Univ. of Michigan, Ann Arbor, MI (U↗
DOE OSTI2021

Effect of excess Mg to control corrosion in molten MgCl 2 and KCl eutectic salt mixture

Structural alloys may experience corrosion when exposed to molten chloride salts due to selective dissolution of active alloying elements. One way to prevent this is to make the molten salt reducing. For the KCl + MgCl 2 eutectic salt mixture, pure Mg can be added to achieve this. However, Mg can form intermetallic compounds with nickel at high temperatures, which may cause alloy embrittlement. This work shows that an optimum level of excess Mg could be added to the molten salt which will prevent corrosion of alloys like 316 H, while not forming any detectable Ni-Mg intermetallic phases on Ni-rich alloy surfaces.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Impacts of divalent cations (Mg 2+ and Ca 2+ ) on PFAS bioaccumulation in freshwater macroinvertebrates representing different foraging modes

Per- and polyfluoroalkyl substances (PFAS) have extensively contaminated freshwater aquatic ecosystems where they can be transported in water and partition to sediment and biota. In this paper, three freshwater benthic macroinvertebrates with different foraging modes were exposed to environmentally relevant concentrations of eight perfluoroalkyl carboxylates (PFCA), three perfluoroalkyl sulfonates (PFSA), and three fluorotelomer sulfonates (FTS) at varying divalent cation concentrations of magnesium (Mg 2+ ) and calcium (Ca 2+ ). Divalent cations can impact PFAS partitioning to solids, especially to sediments, at higher concentrations. Sediment dwelling worms (Lumbriculus variegatus), epibenthic grazing snails (Physella acuta), and sediment-dwelling filter-feeding bivalves (Elliptio complanata) were selected due to their unique foraging modes. Microcosms were composed of synthetic sediment, culture water, macroinvertebrates, and PFAS and consisted of a 28-day exposure period. L. variegatus had significantly higher PFAS bioaccumulation than P. acuta and E. complanata, likely due to higher levels of interactions with and ingestion of the contaminated sediment. “High Mg 2+ ” (7.5 mM Mg 2+ ) and “High Ca 2+ ” (7.5 mM Ca 2+ ) conditions generally had statistically higher bioaccumulation factors (BAF) than the “Reference Condition” (0.2 mM Ca 2+ and 0.2 mM Mg 2+ ) for PFAS with perfluorinated chain lengths greater than eight carbons. Long-chain PFAS dominated the PFAS profiles of the macroinvertebrates for all groups of compounds studied (PFCA, PFSA, and FTS). Furthermore, these results indicate that the study organism has the greatest impact on bioaccumulation, although divalent cation concentration had observable impacts between organisms depending on the environmental conditions. Elevated cation concentrations in the microcosms led to significantly greater bioaccumulation in the test organisms compared to the experimental reference conditions for long-chain PFAS.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Investigating the failure behavior of cast Al-11Ce-0.4Mg alloys using in-situ scanning electron microscopy tensile testing

Within the last decade, research on Al-Ce-Mg alloys has reported promising results for use in cast part applications. In this paper, the failure behavior of cast Al-11Ce-0.4Mg (wt%) was investigated experimentally with focus on the effect the matrix and intermetallic phases have on the fracture propagation behavior at failure. For the first time, in-situ SEM tensile testing was used to study the failure behavior of cast Al-Ce alloys, reporting results for uniaxial, DIC, and single edge notch tensile tests. The results of the in-situ SEM tensile testing were compared with the materials characterization experiments, which included serial sectioning, EBSD, EDS, and fractography. Analysis of EBSD and EDS mapping of cast Al-11Ce-0.4Mg showed that the cast microstructure was a hypereutectic two phase Al-Ce alloy with grains encompassing large complex colonies of laminar eutectic Al 11 Ce 3 intermetallic. The uniaxial tensile results reported the effect casting defects have on the strength and ductility of the alloy, and DIC in-situ testing showed that the eutectic colonies plastically deform less than the matrix phase. In-situ SEM single edge notch tensile testing displayed how the strength of an individual phase affected the crack propagation direction in the alloy. The results of both the materials characterization and in-situ tensile testing experiments on the failure of this alloy revealed further directions for future alloy development that can improve both the strength and fracture toughness of Al-Ce-Mg alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Ordering in liquid and its heredity impact on phase transformation of Mg-Al-Ca alloys

It is a long-sought goal to achieve desired mechanical properties through tailoring phase formation in alloys, especially for complicated multi-phase alloys. In fact, unveiling nucleation of competitive crystalline phases during solidification hinges on the nature of liquid. Here we employ ab initio molecular dynamics simulations (AIMD) to reveal liquid configuration of the Mg-Al-Ca alloys and explore its effect on the transformation of Ca-containing Laves phase from Al 2 Ca to Mg 2 Ca with increasing Ca/Al ratio (r Ca/Al ). There is structural similarity between liquid and crystalline phase in terms of the local arrangement environment, and the connection schemes of polyhedras. The forming signature of Mg 2 Ca, as hinted by the topological and chemical short-range order originating from liquid, ascends monotonically with increasing r Ca/Al . However, Al 2 Ca crystal-like order increase at first and then decrease at the crossover of r Ca/Al = 0.74, corresponding to experimental composition of phase transition from Al 2 Ca to Mg 2 Ca. The origin of phase transformation across different compositions lies in the dense packing of atomic configurations and preferential bonding of chemical species in both liquid and solid. The present finding provides a feasible scenario for manipulating phase formation to achieve high performance alloys by tailoring the crystal-like order in liquid.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Compromise between band structure and phonon scattering in efficient n-Mg 3 Sb 2-x Bi x thermoelectrics

n-type Mg 3 Sb 2 -based materials have become a top candidate for efficient thermoelectric applications within 300–700 K, due to its high band degeneracy, inherently high carrier mobility and low lattice thermal conductivity, as well as its advantages of less toxicity and abundance. Existing works showed that Mg 3 Bi 2 -alloying largely help ensure the exceptional performance, leaving a key issue to be uncovered on the primary mechanisms favoring or limiting the thermoelectric performance of Mg 3 Sb 2-x Bi x alloys. Furthermore we focus on the alloy composition dependent transport properties at various temperatures, with a large volume of experimental data. It is revealed that, with increasing x, the reduction in both inertial mass and lattice thermal conductivity is significantly beneficial, but the closure in band gap leads to a strong compensation due to the bipolar effect. Such a compromise between band structure and phonon scattering results in optimal Mg 3 Bi 2 -alloying concentrations to be about 50%–75% at 300 K, 50%–60% at 450 K and 50% at 600 K, which successfully guiding this work to realize extraordinary thermoelectric figure of merit at these temperatures.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Increasing Capacity in Disordered Rocksalt Cathodes by Mg Doping

Using both computations and experiments, we demonstrate that the performance of Li-excess cation-disordered rocksalt cathodes can be improved by Mg substitution. Furthermore we find that Mg reduces the amount of Li in the compound that is strongly bound to F and thereby increases the capacity. This enables the use of fluorination as a tool to improve stability of the compounds without significant loss of capacity. Mg emerged as the most optimal substitution element from a systematic computational study aimed at identifying inactive doping elements with a strong enough bonding strength to fluorine to displace Li from the F environments. Our results also show that capacity can be traded for cycle life depending on whether Mg is substituted for Li or for the redox metal. This design strategy should be considered in fluorinated cathodes, which will facilitate the design of optimized disordered rocksalt oxyfluoride cathodes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗