Effect of Sr Deficiency on Electrical Conductivity of Yb-Doped Strontium Zirconate.

The effect of Sr-deficiency on microstructure, phase composition and electrical conductivity of SrZrYbO (x = 0.94-1.00) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy.

The GdMgZrO Solid Solution: Ionic Conductivity and Chemical Stability in the Melt of LiCl-LiO.

Materials with pyrochlore structure A2B2O7 have attracted considerable attention owing to their various applications as catalysts, sensors, electrolytes, electrodes, and magnets due to the unique crystal structure and thermal stability. At the same time, the possibility of using such materials for electrochemical applications in salt melts has not been studied. This paper presents the new results of obtaining high-density Mg2+-doped ceramics based on Gd2Zr2O7 with pyrochlore structure and comprehensive investigation of the electrical properties and chemical stability in a lithium chloride melt with additives of various concentrations of lithium oxide, performed for the first time.

Two-Layer Silicene on the SiC Substrate: Lithiation Investigation in the Molecular Dynamics Experiment.

The functioning of the lithium-ion battery anode composed of silicene/SiC composite is studied by molecular dynamics. In this composite, silicene has multiple vacancy defects. Approximately the same degree of lithium filling in such an anode is considered for both horizontal and vertical intercalations.

Electrochemical Reduction of LaO, NdO, and CeO in LiCl-LiO Melt.

The reduction of pellets composed of individual CeO, NdO and a LaO-NdO-CeO mixture by lithium extracted on a cathode during lithium chloride electrolysis at 650 °C was studied. The methods of cyclic voltammetry, electron microscopy, including determination of the elemental composition of the studied objects, and X-ray diffraction analysis were applied for the present study. The reduction degree of rare-earth metal (REM) oxides was determined using both the bromine method and reduction melting of the samples in the graphite crucible.

Proton and Oxygen-Ion Conductivities of Hexagonal Perovskite BaInAlZrO.

The hexagonal perovskite Ba5In2Al2ZrO13 and In3+-doped phase Ba5In2.1Al2Zr0.9O12.

Electronic Properties and Structure of Silicene on Cu and Ni Substrates.

Silicene, together with copper or nickel, is the main component of electrodes for solar cells, lithium-ion batteries (LIB) and new-generation supercapacitors. The aim of this work was to study the electronic properties and geometric structure of "silicene-Ni" and "silicene-Cu" systems intended for use as LIB electrodes. The densities of electronic states, band structures, adhesion energies and interatomic distances in the silicene-(Cu, Ni) systems were determined by ab initio calculations.

Structural, Optical, Luminescence, and Electrical Properties of Eu/Li- and Eu/Na-Codoped Magnesium Bismuth Niobate Pyrochlores.

Eu-doped bismuth-based BiMgNbO ( = Li and Na) pyrochlores were synthesized by the organic-inorganic precursor combustion technique. The study examined the effect of rare earth element Eu doping on the structural, dielectric, optical, and luminescence properties of synthesized materials. The analysis showed that the substitution of Bi cations with Eu leads to dielectric permittivity decreasing due to the structural distortion for the Eu-concentrated compositions and low polarizability of Eu.

Equation of State for Molten Alkali Halides by Thermodynamic Perturbation Theory.

Several variants of the equation of state (EoS) for molten alkali halides are considered using the thermodynamic perturbation theory. Most attention is focused on taking into account the charge-induced dipole (or induction) term to pressure. The model of charged hard spheres of different diameters within the mean spherical approximation is used as a reference system.

Phase Relations in a NaFeO-SnO (0-50 mol.% SnO) System and the Crystal Structure and Conductivity of NaFeSnO.

With the view of developing new materials for sodium and sodium-ion power sources, NaFeO-SnO (0-50 mol.% SnO) powders were synthesized using a solid state method, and their phase composition and crystal structure were studied. A phase of the NaFeSnO composition with a layered rhombohedral structure of the α-NaFeO type was found when the tin dioxide content was 20 mol.

Simulation of Diffusion-Controlled Growth of Interdependent Nuclei under Potentiostatic Conditions.

The problem of diffusion-controlled growth following an instantaneous nucleation event was studied within the framework of a new numerical model, considering the spatial distribution of hemispherical nuclei on the electrode surface and the mutual influence of growing nuclei via the collision of 3D diffusion fields. The simulation of the diffusion-controlled growth of hexagonal and random ensembles was performed at the overpotential-dependent number density of nuclei. The diffusion flow to each nucleus within a random ensemble was simulated by the finite difference method using the derived analytical expressions for the surface areas and the volumes formed at the intersection of 3D diffusion fields with the side faces of a virtual right prism with a Voronoi polygon base.

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO Single Crystal and Fine Powders.

Modifying lithium niobate cation composition improves not only the functional properties of the acousto- and optoelectronic materials as well as ferroelectrics but elevates the protonic transfer in LiNbO3-based electrolytes of the solid oxide electrochemical devices. Molten chlorides and other thermally stable salts are not considered practically as the precursors to synthesize and modify oxide compounds. This article presents and discusses the results of an experimental study of the full or partial heterovalent substitution of lithium ion in nanosized LiNbO3 powders and in the surface layer of LiNbO3 single crystal using molten salt mixtures containing calcium, lead, and rare-earth metals (REM) chlorides as the precursors.

Layered Perovskites BaMInO (M = La, Nd): From the Structure to the Ionic (O, H) Conductivity.

The design of new oxide compounds that can be used as oxygen- or proton-conducting electrolytes for solid oxide fuel cells is actively in progress. Despite the intensive research activities regarding electrolytes with perovskite/fluorite structures, the search for other structural alternatives is of paramount importance. In this study we focus on a novel material with significantly improved properties for the electrochemical purposes.

Understanding the Surface Reconstruction on Ternary W CoB for Water Oxidation and Zinc-Air Battery Applications.

Here, the synthesis of a series of pure phase metal borides is reported, including WB, CoB, WCoB, and W CoB , and their surface reconstruction is studied under the electrochemical activation in alkaline solution. A cyclic voltammetric activation is found to enhance the activity of the CoB and W CoB precatalysts due to the transformation of their surfaces into the amorphous CoOOH layer with a thickness of 3-4 nm. However, such surface transformation does not happen on the WB and WCoB due to their superior structure stability under the applied voltage, highlighting the importance of metal components for the surface reconstruction process.

Nickel-Containing Perovskites, PrNiFeO and PrNiCoO, as Potential Electrodes for Protonic Ceramic Electrochemical Cells.

Protonic ceramic fuel cells (PCFCs) offer a convenient means of converting chemical energy into electricity with high performance and efficiency at low- and intermediate-temperature ranges. However, in order to ensure good life-time stability of PCFCs, it is necessary to ensure rational chemical design in functional materials. Within the present work, we propose new Ni-based perovskite phases of PrNiMO (where M = Co, Fe) for potential utilization in protonic ceramic electrochemical cells.

Electrophoretic Deposition and Characterization of the Doped BaCeO Barrier Layers on a Supporting CeSmO Solid-State Electrolyte.

In this study, the technology of electrophoretic deposition (EPD) micrometer barrier layers based on a BaCeSmCuO (BCSCuO) protonic conductor on dense carrying CeSmO (SDC) solid-state electrolyte substrates is developed. Methods for creating conductive sublayers on non-conductive SDC substrates under EPD conditions, such as the synthesis of a conductive polypyrrole (PPy) layer and deposition of a layer of finely dispersed platinum from a suspension of its powder in isopropanol, are proposed. The kinetics of disaggregation, disperse composition, electrokinetic potential, and the effect of adding iodine to the BCSCuO suspension on these parameters as factors determining the preparation of stable suspensions and successful EPD processes are explored.

Corrosion Behavior of Candidate Functional Materials for Molten Salts Reactors in LiF-NaF-KF Containing Actinide Fluoride Imitators.

Molten fluorides of alkali metals are considered a technological medium for molten salt reactors (MSRs). However, these media are known to be extremely corrosive. The successful implementation of high-temperature technological devices using molten alkali metal fluorides requires the selection of such structural materials that have high corrosion resistance in melts with compositional characteristic of MSRs.

Ternary Mo NiB as a Superior Bifunctional Electrocatalyst for Overall Water Splitting.

Transition metal borides are considered as promising electrocatalysts for water splitting due to their metallic conductivity and good durability. However, the currently reported monometallic and noncrystalline multimetallic borides only show generic and monofunctional catalytic activity. In this work, the authors design and successfully synthesize highly crystalline ternary borides, Mo NiB , via a facile solid-state reaction from pure elemental powders.

Oxygen Vacancy and Core-Shell Heterojunction Engineering of Anemone-Like CoP@CoOOH Bifunctional Electrocatalyst for Efficient Overall Water Splitting.

Constructing cost-efficient and robust bifunctional electrocatalysts for both neutral and alkaline water splitting is highly desired, but still affords a great challenge, due to sluggish hydrogen/oxygen evolution reaction (HER/OER) kinetics. Herein, an in situ integration engineering strategy of oxygen-vacancy and core-shell heterojunction to fabricate an anemone-like CoP@CoOOH core-shell heterojunction with rich oxygen-vacancies supported on carbon paper (CoP@CoOOH/CP), is described. Benefiting from the synergy of CoP core and oxygen-vacancy-rich CoOOH shell, the as-obtained CoP@CoOOH/CP catalyst displays low overpotentials at 10 mA cm for HER (89.

Promising LaMoO-LaMoO Composite Oxygen-Ionic Electrolytes: Interphase Phenomena.

The LaMoO-LaMoO composite materials represent a novel class of highly conductive materials demonstrating increased oxygen-ion conductivity. Extensive research of (100 - )LaMoO-LaMoO composites over a wide range of concentrations ( = 5, 10, 15, 20, 30, and 100) was carried out for the first time. An increase in conductivity, oxygen surface exchange coefficient, and oxygen diffusivity is observed for composites compared to individual oxides, which is associated with the segregation of different ions on the surface of the grains and the formation of a LaMoO new phase at the contact boundary of LaMoO and LaMoO.

Cost Effective Synthesis of Graphene Nanomaterials for Non-Enzymatic Electrochemical Sensors for Glucose: A Comprehensive Review.

The high conductivity of graphene material (or its derivatives) and its very large surface area enhance the direct electron transfer, improving non-enzymatic electrochemical sensors sensitivity and its other characteristics. The offered large pores facilitate analyte transport enabling glucose detection even at very low concentration values. In the current review paper we classified the enzymeless graphene-based glucose electrocatalysts' synthesis methods that have been followed into the last few years into four main categories: (i) direct growth of graphene (or oxides) on metallic substrates, (ii) in-situ growth of metallic nanoparticles into graphene (or oxides) matrix, (iii) laser-induced graphene electrodes and (iv) polymer functionalized graphene (or oxides) electrodes.

Layered Oxygen-Deficient Double Perovskites as Promising Cathode Materials for Solid Oxide Fuel Cells.

Development of new functional materials with improved characteristics for solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) is one of the most important tasks of modern materials science. High electrocatalytic activity in oxygen reduction reactions (ORR), chemical and thermomechanical compatibility with solid electrolytes, as well as stability at elevated temperatures are the most important requirements for cathode materials utilized in SOFCs. Layered oxygen-deficient double perovskites possess the complex of the above-mentioned properties, being one of the most promising cathode materials operating at intermediate temperatures.

Materials ALnInO with Ruddlesden-Popper Structure for Electrochemical Applications: Relationship between Ion (Oxygen-Ion, Proton) Conductivity, Water Uptake, and Structural Changes.

In this paper, the review of the new class of ionic conductors was made. For the last several years, the layered perovskites with Ruddlesden-Popper structure ALnInO attracted attention from the point of view of possibility of the realization of ionic transport. The materials based on Ba(Sr)La(Nd)InO and the various doped compositions were investigated as oxygen-ion and proton conductors.

Mechanism of Dy and Nd Ions Electrochemical Coreduction with Ni, Co, and Fe Ions in Chloride Melts.

The present paper is devoted to the study of the processes of the mechanism of electrochemical coreduction of Dy and Nd ions with Ni, Co, and Fe ions in the equimolar NaCl-KCl melt at 973 K and characterization of the synthesized samples. The performed voltammetry analysis of the electrochemical coreduction processes elucidated a significant difference in the values of the extraction potentials of the studied metals. This melt testifies that intermetallic compounds of Dy and Nd with Ni, Co, and Fe may be synthesized in the kinetic regime.

The Electrical Conductivity of Molten Oxide-Fluoride Cryolite Mixtures.

A new way to reduce the energy consumption during the operation of powerful aluminum reduction cells is suggested via reducing the resistance of the electrolyte, i.e., increasing its electrical conductivity.

Impact of LiBO Addition on Solid Electrode-Solid Electrolyte Interface in All-Solid-State Batteries.

All-solid-state lithium-ion batteries raise the issue of high resistance at the interface between solid electrolyte and electrode materials that needs to be addressed. The article investigates the effect of a low-melting LiBO additive introduced into LiCoO- and LiTiO-based composite electrodes on the interface resistance with a LiLaZrO solid electrolyte. According to DSC analysis, interaction in the studied mixtures with LiBO begins at 768 and 725 °C for LiCoO and LiTiO, respectively.