Accessing Mg-Ion Storage in VPS via Combined Cationic-Anionic Redox with Selective Bond Cleavage.

Magnesium batteries attract interest as alternative energy-storage devices because of elemental abundance and potential for high energy density. Development is limited by the absence of suitable cathodes, associated with poor diffusion kinetics resulting from strong interactions between Mg and the host structure. VPS is reported as a positive electrode material for rechargeable magnesium batteries.

Synthesis, Structure, and Heat Capacity of Some Basic Hydroxohalide Glasses of Zirconium and Hafnium.

This work highlights the synthesis and properties of novel basic hydroxohalide glasses of zirconium and hafnium. The hydroxohalide glasses are M(OH)X·(n)HO where M represents either zirconium or hafnium, and X represents either chloride or bromide. The chemical structure is investigated using X-ray diffraction, total scattering, and the pair distribution function method to identify the local structure and any short-range connectivity.

Evolution of Short-Range Order of Amorphous GeTe Upon Structural Relaxation Obtained by TEM Diffractometry and RMC Methods.

Glasses frequently reveal structural relaxation that leads to changes in their physical properties including enthalpy, specific volume, and resistivity. Analyzing the short-range order (SRO) obtained from electron diffraction by transmission electron microscopy (TEM) in combination with Reverse-Monte-Carlo (RMC) simulations is shown to provide information on the atomic arrangement. The technique elaborated here features several benefits including reliability, accessibility, and allows for obtaining detailed structural data quickly.

Three Phases of Basic Zirconium and Hafnium Hydroxohalides.

Aqueous solutions of zirconium and hafnium (M) halides (X) with atomic ratios α = X/M near 1 form glasses on evaporation. Herein, we describe the preparation and properties of these glasses and discuss the nature of the crystal-glass equilibria beyond the pure glass compositions. Small- and wide-angle X-ray scattering (SWAXS) studies reveal increased polymerization as α decreases from 2 to 1.

Ordered Oxygen Vacancies in the Lithium-Rich Oxide LiCuSbO, a Triclinic Structure Type Derived from the Cubic Rocksalt Structure.

Li-rich rocksalt oxides are promising candidates as high-energy density cathode materials for next-generation Li-ion batteries because they present extremely diverse structures and compositions. Most reported materials in this family contain as many cations as anions, a characteristic of the ideal cubic closed-packed rocksalt composition. In this work, a new rocksalt-derived structure type is stabilized by selecting divalent Cu and pentavalent Sb cations to favor the formation of oxygen vacancies during synthesis.

LiSiOCl: A Hexagonal Argyrodite Based on Antiperovskite Layer Stacking.

A hexagonal analogue, LiSiOCl, of the cubic lithium argyrodite family of solid electrolytes is isolated by a computation-experiment approach. We show that the argyrodite structure is equivalent to the cubic antiperovskite solid electrolyte structure through anion site and vacancy ordering within a cubic stacking of two close-packed layers. Construction of models that assemble these layers with the combination of hexagonal and cubic stacking motifs, both well known in the large family of perovskite structural variants, followed by energy minimization identifies LiSiOCl as a stable candidate composition.

One Site, Two Cations, Three Environments: s and s Electronic Configurations Generate Pb-Free Relaxor Behavior in a Perovskite Oxide.

The piezoelectric devices widespread in society use noncentrosymmetric Pb-based oxides because of their outstanding functional properties. The highest figures of merit reported are for perovskites based on the parent Pb(MgNb)O (PMN), which is a relaxor: a centrosymmetric material with local symmetry breaking that enables functional properties, which resemble those of a noncentrosymmetric material. We present the Pb-free relaxor (KBi)(MgNb)O (KBMN), where the thermal and (di)electric behavior emerges from the discrete structural roles of the s K and s Bi cations occupying the same A site in the perovskite structure, as revealed by diffraction methods.

Computationally Guided Discovery of the Sulfide LiAlS in the Li-Al-S Phase Field: Structure and Lithium Conductivity.

With the goal of finding new lithium solid electrolytes by a combined computational-experimental method, the exploration of the Li-Al-O-S phase field resulted in the discovery of a new sulfide LiAlS. The structure of the new phase was determined through an approach combining synchrotron X-ray and neutron diffraction with Li and Al magic-angle spinning nuclear magnetic resonance spectroscopy and revealed to be a highly ordered cationic polyhedral network within a sulfide anion -type sublattice. The originality of the structure relies on the presence of AlS repeating dimer units consisting of two edge-shared Al tetrahedra.

Insights on the Proton Insertion Mechanism in the Electrode of Hexagonal Tungsten Oxide Hydrate.

This study reveals the transport behavior of lattice water during proton (de)insertion in the structure of the hexagonal WO·0.6HO electrode. By monitoring the mass evolution of this electrode material via electrochemical quartz crystal microbalance, we discovered (1) WO·0.

New Mechanistic Insights on Na-Ion Storage in Nongraphitizable Carbon.

Nongraphitizable carbon, also known as hard carbon, is considered one of the most promising anodes for the emerging Na-ion batteries. The current mechanistic understanding of Na-ion storage in hard carbon is based on the "card-house" model first raised in the early 2000s. This model describes that Na-ion insertion occurs first through intercalation between graphene sheets in turbostratic nanodomains, followed by Na filling of the pores in the carbon structure.