Synergizing Phase and Cavity in CoMoOxSy Yolk–Shell Anodes to Co‐Enhance Capacity and Rate Capability in Sodium Storage

Sodium‐ion batteries (SIBs) have been recognized as the promising alternatives to lithium‐ion batteries for large‐scale applications owing to their abundant sodium resource. Currently, one significant challenge for SIBs is to explore feasible anodes with high specific capacity and reversible pulverization‐free Na⁺ insertion/extraction. Herein, a facile co‐engineering on polymorph phases and cavity structures is developed based on CoMo‐glycerate by scalable solvothermal sulfidation. The optimized strategy enables the construction of CoMoO_xS_y with synergized partially sulfidized amorphous phase and yolk–shell confined cavity. When developed as anodes for SIBs, such CoMoO_xS_y electrodes deliver a high reversible capacity of 479.4 mA h g^?1 at 200 mA g^?1 after 100 cycles and a high rate capacity of 435.2 mA h g^?1 even at 2000 mA g^?1, demonstrating superior capacity and rate capability. These are attributed to the unique dual merits of the anodes, that is, the elastic bountiful reaction pathways favored by the sulfidation‐induced amorphous phase and the sodiation/desodiation accommodatable space benefits from the yolk–shell cavity. Such yolk–shell nano‐battery materials are merited with co‐tunable phases and structures, facile scalable fabrication, and excellent capacity and rate capability in sodium storage. This provides an opportunity to develop advanced practical electrochemical sodium storage in the future.     

Some aspects of solidification and homogenisation of Mg–Ag alloys

The model of non-equilibrium solidification based on assumption of full diffusion in liquid and its lack in the solid state has been adopted in Krupkowski's evaluation to Mg–Ag alloys to describe maximum microsegregation of components in the solid solution resulting in appearance of maximum amounts of non-equilibrium phases. The results were then compared with experimental in MgAg 2.5 wt.% alloys with and without addition of 0.6 wt.% zirconium and 2.5 wt% neodymium (RE) by means of scanning and transmission electron microscopy equipped with an energy dispersive spectrometer. It was found that zirconium entered the solid solution, while neodymium appeared as a net of the Mg–Ag–Nd ternary eutectic.The homogenisation process has been studied based on hardness measurements and structure analysis. The times and temperatures of homogenisation to receive uniform distribution of components in the solid solution have been chosen neglecting the remaining eutectic precipitates due to economical reasons.     

Self‐Assembled Ordered Three‐Phase Au–BaTiO3–ZnO Vertically Aligned Nanocomposites Achieved by a Templating Method

Complex multiphase nanocomposite designs present enormous opportunities for developing next‐generation integrated photonic and electronic devices. Here, a unique three‐phase nanostructure combining a ferroelectric BaTiO₃, a wide‐bandgap semiconductor of ZnO, and a plasmonic metal of Au toward multifunctionalities is demonstrated. By a novel two‐step templated growth, a highly ordered Au–BaTiO₃–ZnO nanocomposite in a unique “nanoman”‐like form, i.e., self‐assembled ZnO nanopillars and Au nanopillars in a BaTiO₃ matrix, is realized, and is very different from the random three‐phase ones with randomly arranged Au nanoparticles and ZnO nanopillars in the BaTiO₃ matrix. The ordered three‐phase “nanoman”‐like structure provides unique functionalities such as obvious hyperbolic dispersion in the visible and near‐infrared regime enabled by the highly anisotropic nanostructures compared to other random structures. Such a self‐assembled and ordered three‐phase nanocomposite is obtained through a combination of vapor–liquid–solid (VLS) and two‐phase epitaxy growth mechanisms. The study opens up new possibilities in the design, growth, and application of multiphase structures and provides a new approach to engineer the ordering of complex nanocomposite systems with unprecedented control over electron–light–matter interactions at the nanoscale.     

Missing Link between Helical Nano‐ and Microfilaments in B4 Phase Bent‐Core Liquid Crystals,and Deciphering which Chiral Center Controls the Filament Handedness

The range of possible morphologies for bent‐core B4 phase liquid crystals has recently expanded from helical nanofilaments (HNFs) and modulated HNFs to dual modulated HNFs, helical microfilaments, and heliconical‐layered nanocylinders. These new morphologies are observed when one or both aliphatic side chains contain a chiral center. Here, the following questions are addressed: which of these two chiral centers controls the handedness (helicity) and which morphology of the nanofilaments is formed by bent‐core liquid crystals with tris‐biphenyl diester core flanked by two chiral 2‐octyloxy side chains? The combined results reveal that the longer arm of these nonsymmetric bent‐core liquid crystals controls the handedness of the resulting dual modulated HNFs. These derivatives with opposite configuration of the two chiral side chains now feature twice as large dimensions compared to the homochiral derivatives with identical configuration. These results are supported by density functional theory calculations and stochastic dynamic atomistic simulations, which reveal that the relative difference between the para‐ and meta‐sides of the described series of compounds drives the variation in morphology. Finally, X‐ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) data also uncover the new morphology for B4 phases featuring p2/m symmetry within the filaments and less pronounced crystalline character.     

Polysilazane‐Type Coatings on Mo–Si–B Alloys: A Thermodynamic Assessment of the Phase Composition

Thermodynamic analysis is conducted to identify the most probable phase composition of a polysilazane‐type coating system on Mo–Mo₃Si(A15)–Mo₅SiB₂(T2) alloy. The Free Gibbs Energy of chemical reactions between these constituents and resulting phases are calculated. Silicon nitrides, silicon oxynitrides, and molybdenum silicides have been found in the phase equilibrium between the gas phase and condensed species of the proposed coating system. Silicon oxynitride and silica as components in the coating system are potential candidates for Mo–Si–B alloy oxidation protection in air at high temperatures.

     

Icosahedral Al–Mn phases grown in diffusion-limited conditions

Sequential deposition of Mn on a polycrystalline Al layer at 523–573 K was found to result in an anomalous icosahedral (i) Al–Mn phase, characterized by alterations of intensity- and linewidth ratios. The anomalies suggest a non-equilibrium atom distribution, related to the limited diffusion of Al through the already-formed layer of i-AlMn. The activation energy of Al diffusion was inferred from X-ray diffraction (XRD) data taken for different deposition temperatures.