Substitutional Elements Research Articles

Research Progress on P2/O3-Composite Layer Metal Oxide Cathode Materials for Sodium-Ion Batteries

Abstract The high cost and uneven distribution of lithium resources have prompted searches for alternatives to lithium-ion batteries. Among various alternatives, the sodium layered oxide cathode materials, have shown significant research potential due to their low cost. Layered oxide materials can be categorized into sodium-rich O3 types and sodium-deficient P2 types, which have different structural features. O3 type materials offer high specific capacities but suffer from complex pathways for Na+ de-intercalation, slow Na+ diffusion, and poor air stability. P2 type materials are limited in full cell applications due to their lower practical specific capacities. Therefore, researchers conceived the idea of combining the advantages of both to construct P2/O3 composite structure cathode materials (CSMs), utilizing the synergistic effects of the CSMs to overcome the limitations of single structure material, and successfully synthesized CSMs with appropriate specific capacities. These materials effectively suppress unfavorable phase transitions and enhance Na+ diffusion coefficient, thereby improving electrochemical performance. This paper reviews the recent advancements in CSMs for sodium-ion batteries, highlighting synthesis strategies that incorporate "cationic potential" theory, element substitution, sodium content adjustment, and control of calcination processes to synthesize diverse CSMs.

Experimental investigation of martensitic transformation in Ni2MnGa alloys with elemental substitutions

Experimental investigation of martensitic transformation in Ni2MnGa alloys with elemental substitutions

Tailoring the Structural, Dielectric and Ferroelectric Properties of the Textured Bismuth Titanate Ceramics by Rare Earth Element Substitution Towards Energy Storage Applications

Tailoring the Structural, Dielectric and Ferroelectric Properties of the Textured Bismuth Titanate Ceramics by Rare Earth Element Substitution Towards Energy Storage Applications

Computational detangling chalcogen elements substitutions associated ESDPT mechanism for oxazolinyl-substituted hydroxyfluorene derivatives

In view of the distinguished photochemical and photobiological characteristics of oxazolinyl-substituted hydroxyfluorene and its derivatives, herein, we mainly focus on probing into excited state behaviors of the novel 9,9-dimethyl-3,6-dihydroxy-2,7-bis(4,5-dihydro-4,4-dimethyl-2-oxazolyl) fluorene (Oxa-OH) derivatives. In light of the significant effects resulting from substituting oxygen elements, three Oxa-OH derivatives (i.e., Oxa-OO, Oxa-SS and Oxa-SeSe fluorophores) are considered in this work. For these three different fluorophores, we detangle the effects of atomic electronegativity and charge recombination related to oxygen elements in excited state double proton transfer (ESDPT) processes. Because of the low potential energy barriers, we confirm the ESDPT happens by the sequential type. Based on heterosubstituted Oxa-OS and Oxa-OSe compounds, we further verify the chalcogen atomic-electronegativity-regulated stepwise ESDPT mechanism. We sincerely wish our work could provide a theoretical reference for proving this novel mechanism of ESDPT experimentally.

Synthesis, Structure and Properties of Compounds Derived from Kotoite-related Structures: A2MB2O6 (A=Zn, Ba, Pb; B=Pb, Ba, Zn, Cu).

A series of compounds with the general formula A2MB2O6 (A=Zn, Ba, Pb; B=Pb, Ba, Zn, Cu) related to the kotoite structure has been prepared employing high-temperature solid state methods. The substitution of transition elements in place of Zn2+ ions resulted in colored compounds. The optical absorption spectra could be explained based on Tanabe-Sugano diagram and allowed d-d transitions. Dielectric studies on Ba2ZnB2O6, (Ba1.5Pb0.5)ZnB2O6, PbZn2B2O6, Pb1.5Zn1.5B2O6, BaZn2B2O6 and Pb2CuB2O6 at room temperature indicate reasonable values at low frequencies, which decrease on increasing frequencies. Magnetic study of synthesized single-phase compounds BaZnCoB2O6 and Pb2CuB2O6 have been performed. The substitution of Eu3+, Tb3+ and Tm3+ in place of Ba2+ in Ba2ZnB2O6, gives rise to the expected emission of red, green and blue colors. Suitable modifications of the different phosphors in Ba2ZnB2O6, resulted in white-light emission in Ba2ZnB2O6. The Pb2CuB2O6 compound was found to be a good catalyst in the ipso-hydroxylation of arylboronic acids.

Institutional Complementarity and Substitution in Indian Multinational Enterprises’ Cross-Border Investment Decisions

The assumption that better institutions are favoured in multinational enterprises’ (MNEs) location choices has been questioned in terms of whether emerging market MNEs might have different capabilities associated with the institutional conditions in their home country that they may exploit when internationalizing. They might seek to expand both to better institutional environments (institutional substitution) and to other emerging market environments (institutional complementarity). We examine if elements of institutional complementarity and substitution are evident in the internationalization decisions of Indian MNEs, and whether there are boundary conditions or limits attached to the benefits of these two effects. Our arguments are tested on a sample of Indian MNEs’ cross-border acquisitions between 2002 and 2021. The study differentiates between institutional distance effects in terms of both magnitude and direction, and institutional quality. We raise the notion of “institutional ranges or thresholds” (different points on the institutional profile distribution representing varying levels of institutional quality) and explicitly seek to identify such thresholds where the effects of institutional complementarity and substitution may set in and/or disappear, and why that may be the case.

Machine-learning surrogate models for particle insertions and element substitutions.

Two machine-learning-aided thermodynamic integration schemes to compute the chemical potentials of atoms and molecules have been developed and compared. One is the particle insertion method, and the other combines particle insertion with element substitution. In the former method, the species is gradually inserted into the liquid and its chemical potential is computed. In the latter method, after the particle insertion, the inserted species is substituted with another species, and the chemical potential of this new species is computed. In both methods, the thermodynamic integrations are conducted using machine-learned potentials trained on first-principles datasets. The errors of the machine-learned surrogate models are further corrected by performing thermodynamic integrations from the machine-learned potentials to the first-principles potentials, accurately providing the first-principles chemical potentials. These two methods are applied to compute the real potentials of proton, alkali metal cations, and halide anions in water. The applications indicate that these two entirely different thermodynamic pathways yield identical real potentials within statistical error bars, demonstrating that both methods provide reproducible real potentials. The computed real potentials and solvation structures are also in good agreement with past experiments and simulations. These results indicate that machine-learning surrogate models enabling particle insertion and element substitution provide a precise method for determining the chemical potentials of atoms and molecules.

Accelerated Exploration of Empty Material Compositional Space: Mg-Fe-B Ternary Metal Borides.

Borides are a family of materials with valuable properties for various applications. Their diverse structures and compositions, yet disparity in the constituent chemical elements for the known compounds, give elemental substitutions for prototypes great potential for material discovery. To explore uncharted material compositional space, we develop a workflow that joins high-throughput crystal structure prediction and automated diffraction pattern matching to discover new compounds with significant prediction and synthesis hurdles. Utilizing the workflow, we explore the empty Mg-Fe-B ternary compositional space, previously uncharted largely due to the immiscibility of Mg and Fe, as a paradigm. A total of 275 ternary boride prototypes are classified, using which we predict 23 (158) stable and metastable ternary phases within 50 (200) meV/atom above the convex hull. We identify Gd2(FeB)7-type Mg2Fe7B7 and ZrCo3B2-type MgFe3B2 to match previously unsolved experimental powder X-ray diffraction (PXRD) patterns. The discovered Mg2Fe7B7 and related channeled structures feature mismatched Mg and (FeB) sublattice periods, for which we conduct structural analyses with respect to the PXRD. They are predicted to exhibit exceptionally fast superionic transport of Mg and outstanding electrochemical performance, which serve as post-Li-ion battery candidate electrode materials. This result opens a new avenue for borides' potential applications as electrode materials and fast ionic conductors. This work also portrays the map and landscape of ternary metal borides with similar chemical environments. With high efficiency, the prototype- and PXRD-assisted crystal structure prediction workflow opens a new avenue for exploring various material compositional spaces across the periodic table.

Ideal spin-orbit-free Dirac semimetal and diverse topological transitions in Y8CoIn3 family

Topological semimetals, known for their intriguing properties arising from band degeneracies, have garnered significant attention. However, the discovery of a material realization and the detailed characterization of spinless Dirac semimetals have not yet been accomplished. Here, we propose from first-principles calculations that the RE8CoX3 group (RE = rare earth elements, X = Al, Ga, or In) contains ideal spinless Dirac semimetals whose Fermi surfaces are fourfold degenerate band-crossing points (without including spin degeneracy). Despite the lack of space inversion symmetry in these materials, Dirac points are formed on the rotation-symmetry axis due to accidental degeneracies of two bands corresponding to different 2-dimensional irreducible representations of the C6v group. We also investigate, through first-principles calculations and effective model analysis, various phase transitions caused by lattice distortion or elemental substitutions from the Dirac semimetal phase to distinct topological semimetallic phases such as nonmagnetic linked-nodal-line and Weyl semimetals (characterized by the second Stiefel–Whitney class) and ferromagnetic Weyl semimetals.

Three-dimensional higher-order saddle-point-induced flatbands in Co-based kagome metals

The saddle point (Van Hove singularity) exhibits a divergent density of states in two-dimensional systems, leading to fascinating phenomena such as strong correlations and unconventional superconductivity, yet it is seldom observed in three-dimensional (3D) systems. In this work we find two types of 3D higher-order saddle points (HOSPs) in emerging 3D kagome metals YbCo6Ge6 and MgCo6Ge6. Both HOSPs exhibit a singularity in their density of states, which is significantly enhanced compared to the ordinary saddle point. The HOSP near the Fermi energy generates a flatband extending a large area in the Brillouin zone, potentially amplifying the correlation effect and fostering electronic instabilities. Two types of HOSPs exhibit distinct robustness upon element substitution and lattice distortions in these kagome compounds. Our work paves the way for engineering exotic band structures, such as saddle points and flatbands, and exploring interesting phenomena in Co-based kagome materials. Published by the American Physical Society 2024

Superconducting properties and electronic structure of CuAl2-type transition-metal zirconide Fe1-xNixZr2

CuAl2-type transition-metal (Tr) zirconides are a superconductor family, and the Tr-site element substitution largely modifies its transition temperature (Tc). Here, we synthesized polycrystalline samples of Fe1-xNixZr2 by arc melting. The crystal structure and the superconducting properties were studied through synchrotron X-ray diffraction, magnetic susceptibility, electrical resistivity, and specific heat measurements. Bulk superconductivity was observed for 0.4 ≤ x ≤ 0.8, and the highest Tc of 2.8 K was observed for x = 0.6. The obtained superconductivity phase diagram exhibits a dome-shaped trend, which is similar to unconventional superconductors, where magnetic fluctuations are essential for superconductivity. In addition, from the c/a lattice constant ratio analysis, we show the possible relationship between the suppression of bulk superconductivity in the Ni-rich compositions and a collapsed tetragonal transition.

Prediction of Li-ion conductivity in Ca and Si co-doped LiZr2(PO4)3 using a denoising autoencoder for experimental data

All-solid-state batteries composed of inorganic materials are in high demand as power sources for electric vehicles owing to their improved safety, energy density, and overall lifespan. However, the low ionic conductivity of inorganic solid electrolytes has limited the performance and adoption of inorganic all-solid-state batteries. The solid electrolyte LiZr2(PO4)3 has attracted attention owing to its high Li-ion conductivity. The ionic conductivity of LiZr2(PO4)3 changes with the crystalline phase obtained, which varies based on composition control through elemental substitution and process conditions such as sintering temperature. Traditionally, optimizing such parameters and understanding their relationship to physical properties have relied on researcher experience and intuition. However, a recent use of a materials informatics approach utilizing machine learning shows promise for more efficient property optimization. This study proposes a deep learning model to correlate powder X-ray diffraction (XRD) profiles with the activation energy (Ea) for Li-ion conduction, thereby enhancing the interpretability of the measurement data. XRD profiles, which contain information on crystal structure, lattice strain, and particle size, were used as-is (i.e., without preprocessing) in the deep learning model. An attention mechanism was introduced to the deep learning model that focuses on XRD crystal-structure information and visualization of important factors embedded in the XRD profiles. The highlighted areas in the output of this model successfully predict LiZr2(PO4)3 phases with low Ea (high Li conductivity) and high Ea (low Li conductivity). Moving forward, this deep learning model can offer new insights to materials researchers, potentially contributing to the discovery of new solid electrolyte materials.

A Review of Perovskite-based Lithium-Ion Battery Materials

Lithium-ion batteries (Li-ion batteries or LIBs) have garnered significant interest as a promising technology in the energy industry and electronic devices for the past few decades owing to their superior energy and power density profiles, small size, long cycle life, low self-discharge rate, no memory effect, long-lasting power properties, and environmental friendly. The ongoing advancement of electrode and electrolyte materials has contributed significantly to enhancing and spreading the application of lithium-ion battery technology. Among the non-precious metal-based materials, perovskites have emerged as attention over the last decade, holding a prominent position in materials and energy. Due to their unique physical and chemical properties, these materials have garnered particular interest for their potential application in electrochemical energy devices. Perovskite oxides have piqued the interest of researchers as potential catalysts in Li-O₂ batteries due to their remarkable electrochemical stability, high electronic and ionic conductivity, and the ability to modify their properties through doping and element substitution. The purpose of this article is to provide an overview of recent developments in the application of perovskites as lithium-ion battery materials, including the exploration of novel compositions and structures, optimization of fabrication methods, and a deeper understanding of the fundamental mechanisms that can unveil the potential of perovskite materials.

The Application of Sulfur–Metal Mass Ratios in Metal Sulfides in Assessing Prospects for Deep Metallogeny: A Case Study of the Tongshan Copper Deposit in Heilongjiang Province, Northeast China

Sulfur–metal mass ratios (SMMRs) between sulfur and metal elements (Cu, Pb, Zn, Ag, Fe, etc.) in metal sulfides are fixed in idealized compositions, so they should have a relatively fixed proportion in terms of mass without considering the presence of structural defects such as vacancies or substitution elements. Rock bodies with an SMMR of S far greater than the common metal sulfides may contain additional sulfides of other metals. We studied the Tongshan copper deposit in NE China and calculated the mass transfer of various elements in drill hole ZK611 samples. The data show a S influx of 7160 g/t, a Cu influx of 5469 g/t, and an Fe influx of 8796 g/t in the Cu ore body. Below the Cu ores, the average influx is 18,600 g/t of S, 650 g/t of Cu, and 5360 g/t of Fe, which provides an SMMR far above common mineral sulfide values. Further studies indicated that this rock unit contains fine-grained sphalerite and galenite, and when Zn and Pb are included in the rock SMMR calculations, values closer to the mineral sulfides emerge. These results imply that the coordinating balance relationship of S content with Fe and other ore-forming metals could provide direct information for assessing metallogenic prospects.

Two-Dimensional MoSi2N4 Family: Progress and Perspectives Form Theory.

Recently, a new two-dimensional (2D) layered MoSi2N4 has been successfully synthesized by chemical vapor deposition without knowing the 3D counterparts [ Science 2020, 369, 670-674]. The unique septuple-atomic-layer structure and diverse composition of MoSi2N4 have drawn tremendous interest in studying 2D MA2Z4 systems based on the MoSi2N4 structure. As an emerging family of 2D materials, MA2Z4 materials exhibit a wide range of properties and excellent tunability, making them highly promising for various applications. Herein, we summarize recent significant progress in property characterization of the MA2Z4 family. The electronic, magnetic, thermal transport, and superconducting properties, including their tunability through strain engineering and elemental substitution, are presented and elaborated in detail. Further perspectives and new opportunities of the emerging MA2Z4 family are presented at the end of this Perspective.

Integrated geochemical analysis of urban and peri-urban soils: a case study of Lamia City, Greece.

The occurrence of Potentially Toxic Elements (PTEs) and other chemical elements in urban and peri-urban soils impacts human health and quality of life, posing a challenge for geoscientists. This study investigated the soil geochemistry of Lamia City, focusing on identifying the geogenic and anthropogenic origins of elements. A total of 168 topsoil samples (0-10cm) were collected in April 2023, and the analysis included the near-total concentrations of 51 elements. Descriptive, correlation, multivariate statistics (i.e., Factor Analysis-FA and Hierarchical Cluster Analysis-HCA), Geographic Information Systems (GIS) mapping, and mineralogical analysis were employed to identify potential element sources. The results indicated that the elements in soils originated from geogenic, anthropogenic, and mixed sources. Geogenic origins are associated with ultramafic rocks (e.g., Mg, Cr, Ni, Co, Fe, Sc, Mn), carbonate rocks (e.g., Ca, Sr), and Quaternary sediments (e.g., K, Na, Ba, Tl, Be, Rb, Ti, V, Ga, and Rare Earth Elements-REEs); associations are linked to specific identified minerals. All applied statistical analyses reveal that the mobility of chemical elements in the urban and peri-urban soils of Lamia city is primarily affected by geochemical processes such as element substitution, chemical weathering, pedogenesis, adsorption, precipitation, evaporation, and organic matter presence. The P, Ag, Hg, Pb, Sn, Zn, Sb, Cd, Cu, and U were associated with anthropogenic influences, particularly in areas with high population density, heavy vehicle traffic, and intensive agricultural practices. Additionally, some elements (e.g., Ca, Cd, Cu, Mo, Mn, and Li) exhibited mixed origins. This integrated approach offers valuable insights into the spatial distribution and sources of PTEs in urban and peri-urban environments, providing critical information for environmental management and public health protection strategies.

Non-destructive Analytical Study of Raman Spectra Variations and Mechanisms of Calcite and Aragonite in Modern and Fossilized Oysters.

Oyster fossils are some of the most common bivalve mollusk fossils found all over the world, they are different from other fossils because the oyster is still alive in the present day, and the body structure of modern oyster is almost the same as that of ancient one. Therefore, we designed a control experiment comparing the Raman spectra of minerals from both modern oysters and fossil oysters to explore the mechanism of oyster's fossilization process, which is considered to be helpful for investigating biological evolution or paleoenvironment. The oyster fossil sample was found in Nagi-Cho, Okayama Prefecture, Japan. We focused on the variations of band position and full width half-maximum of ν1 Raman band (symmetric stretching mode) of calcite (CaCO3) from modern and fossil oysters and the mineral conversion between calcite and aragonite (CaCO3) around the adductor muscle inside the oyster. Compared to modern oysters, the ν1 band at around 1086 cm-1 of calcite from oyster fossils shifted to a high wavenumber region, and the possible reason for this phenomenon is considered an elemental substitution between Ca2+ and Mg2+. As for aragonite around adductor muscle in fossil oysters, it has been found by Raman spectra that most of the aragonite has been converted into calcite because calcite has a relatively more stable structure.

A Versatile InF3 Substituted Argyrodite Sulfide Electrolyte Toward Ultrathin Films for All‐Solid‐State Lithium Batteries

AbstractAll‐solid‐state lithium batteries (ASSLBs) incorporating sulfide solid electrolytes capture great attention due to their intrinsic safety features and high energy density. Nevertheless, the implementation of sulfide solid electrolytes faces significant challenges, including moisture sensitivity, narrow intrinsic electrochemical windows, and excessively thick solid electrolyte layers. Here, the substitution of In for P and F for Cl in argyrodite sulfide Li5.7PS4.7Cl1.3 is presented. With appropriate elemental substitutions, the Li symmetric cells exhibit a high critical current density value of 2.5 mA cm−2 and deliver prolonged plating/stripping over 1000 h at 1 mA cm−2 and 25 °C. Further, the Li5.82P0.94In0.06S4.7Cl1.12F0.18 displays high chemical stability toward organic solvents, which is further demonstrated by the density functional theory (DFT) calculations. Using polyisobutylene as a binder, a uniform sulfide film (35 µm) is prepared by slurry casting and hot pressing process, delivering a high ionic conductivity of 1.4 mS cm−1 at 25 °C. Coupled with FeS2 and LiCoO2 cathode, the all‐solid‐state lithium metal cell exhibits a long cycling life and excellent rate performance. This study provides a design strategy and reveals the importance of high‐performance sulfide SEs in the scalable production of sulfide film.

Local Electronic Structure Regulation Enabling Fluorophosphates Cathode with Improved Redox Potential and Reversible Capacity for Sodium-Ion Batteries.

Mn-based fluorophosphates have attracted much attention as cathodes for sodium-ion batteries owing to their high cost effectiveness, considerable capacity, and stable framework. However, the fascinating Mn3+/2+ redox couple suffers from inadequate activation due to the Mn-O covalent character and poor electronic conductivity, impeding its further applications. Herein, a local electronic structure regulation strategy is proposed to improve the Mn3+/2+ redox potential and reversible capacity simultaneously through introducing elements with low-energy 3d orbitals to expand the energy gap between the eg orbitals and Fermi energy of Na. Moreover, the 3d element substitution serves to narrow the band gap toward the improved intrinsic electronic conductivity. In comparison with pristine Na2Fe0.45Mn0.55PO4F, the as-prepared Na2Fe0.45Mn0.4V0.1PO4F cathode achieves an increase from 3.5 to 3.6 V in the high-voltage platform and an improvement in energy density from 330 to 361 Wh kg-1. This work inspires new ideas in adjusting the redox potential of polyanionic cathodes through deliberate regulation of the local electronic structure.

The ore mineralization of the gold-bearing Murunsky node located within the Aldan Shield

Mineralogical and geochemical investigations of the underexplored gold ore deposits within the Murunsky node, specifically the Seredinskoye and Andreevskoye ore fields, were conducted utilizing mineralogical and microprobe analytical techniques. The study identified several minerals, including bismuth minerals such as wittichenite and aikinite; cadmium mineral greenockite; cobalt minerals cobaltite and carrollite; arsenic minerals arsenosulvanite and tennantite; antimony minerals antimonite and tetrahedrite; tellurium minerals hessite and Te-canfieldite; mercury mineral cinnabar; thallium minerals raguinite and copper-rich talcusite; and tin minerals kesterite and jeanbandyite. Additionally, potassium sulfide djerfisherite with an unusual silver admixture was discovered. The findings underscore the remarkable and largely untapped potential of the Murunsky massif, particularly concerning its ore mineralization. A notable characteristic of the identified minerals is their non-stoichiometric composition, which includes the presence of impurities and isomorphic substitution of elements, attributed to the disequilibrium conditions under which they formed. The discoveries of raguinite and jeanbandyite represent the first occurrences of these minerals in Russia.