Crystal structure and imperfection of the perovskite-like proton conductor Ba4Ca2Nb2O11

The crystal structure complex oxide Ba4Ca2Nb2O11 in anhydrous and hydrated forms was studied by the method of neutron diffraction, the preferred localizations of protons were set. The hydration process with temperature variation and the partial pressure of water vapor was studied. It is established that the crystallographic non-equivalence of OH-groups in the structure determines their different thermal stability. The quasi-chemical approach was proposed that describes the formation of proton defects in oxides with structural disordering

Effect of anion doping on mobility of ionic charge carriers in solid solutions based on Ba2In2O5

In the work, mobilities of oxygen and protons are determined for F --substituted solid solutions based on brownmillerite Ba 2In2O5 and their concentration dependences are analyzed. It is found that small additives of the more mobile anion (F - ions) promote an increase in oxygen mobility as a result of additional effects of repulsion of ions of different nature in the anion sublattice. Mobility of oxygen at high fluoride concentrations decreases due to the overlapping of migration paths of diffusion, as both anions, fluoride ions and oxygen ions, move via oxygen vacancies. Concentration dependences of mobility of proton carriers have a similar character, which is related to the effect of the oxygen sublattice. The anion doping method used in the work can be recommended as the general method for improvement of the transport characteristics of oxygen-ionic and protonic conductors with a perovskite-like structure. © 2013 Pleiades Publishing, Ltd

Electrical properties of Ba2(In1-x Al x )2O5 solid solutions

The electric conductivity of perovskite-like Ba2(In 1-x Al x )2O5 solid solutions (0 < x ≤ 0.20) characterized by structural disordering in the oxygen sublattice was studied as a function of temperature and partial pressure of oxygen in an atmosphere with a low content of water vapors (pH2O = 3 Ч 10-5 atm). When In3+ was partially replaced by Al3+, the oxygen ion conductivity increased because of the disordering of oxygen structural vacancies, leading to a significant increase in the total electric conductivity of the samples. © 2013 Pleiades Publishing, Ltd

Electric properties of oxyfluorides Ba2In2O 5-0.5x F x with brownmillerite structure

Synthesis of fluoro-substituted substances based on brownmillerite Ba 2In2O5 is carried out. The width of the homogeneity region of the Ba2In2O5-0.5x F x (0 < x ≤ 0.25) solid solution was established using X-ray analysis. Measurement of temperature dependences of conductivity in atmospheres with different partial pressure of water vapor (pH2O = 3.3 and 2 Ч 103 Pa) showed an increase in conductivity at T ≤ 550 C in a humid atmosphere, which is due to appearance of proton transport. The dependence of conductivity on partial oxygen pressure (pO2 = 0.21 Ч 105 to 10-15 Pa) is studied in the temperature range of 500-1000 C; ion transport numbers are calculated. The method of polarization measurements was used to determine transport numbers of fluoride. Total conductivity is divided into ion (proton, oxygen, and fluoride ion) and electron components. Analysis of concentration dependences of conductivities showed that low concentrations of fluoride allow increasing both the total and partial conductivities (oxygen-ion and proton) and, besides, allow shifting the "order-disorder" phase transition by 100 C to the low temperature range. © 2013 Pleiades Publishing, Ltd

Electrical Properties of (1–x)La2Mo2O9-xLa2Mo3O12 (x = 0.15) Composite System

Electrical properties of (1–x)La2Mo2O9 –xLa2Mo3O12 (x = 0.15) composite system areinvestigated. Introduction of an inert additional phase La2Mo3O12 (adjacent phase to La2Mo2O9 in the phase diagram) results in an increase in conductivity of composite by approximately one order of magnitude. This increase is associated with the appearance of a composite effect. The dominant ionic conductivity is maintained in the wide range of oxygen partial pressures. The calculated ion transport numbers are close to 1. Keywords: lanthanum molybdate, LAMOX, heterogeneous doping, composites, oxide–ion conductivit

Formation of paradigmatic theory of regional economy

This paper reviews the evolution of scientific ideas about the regional economy as an independent direction of economic knowledge. The growing interest of scientists, university lecturers and specialists to the regional economy is noticed. The authors pay special attention to the origins of the regional economy, the contribution of Russian scientists to the disclosure of the content and nature of economic regionalization of the country as well as highlight the role of Soviet geographers and economists in developing the theory of clusters and the study of challenges to the rational distribution of production forces. It is emphasized that the new scientific discipline — regional economy — was born in the acute scientific discussions between Soviet geographers and economists, particularly regarding the subject of investigation. The conclusion is substantiated that so far in economic science four major views on the subject of understanding and interpretation of the regional economy were formed. The authors pay attention to the fact that at present there is a further extension of the subject of the regional economy, mainly over the border of the material space and location of productive forces. The paper concludes that the formation of a modern paradigm of regional economy should be based on several basic principles, among which are the following ones: consideration of the regional economy as an evolving complex structural discipline; territoriality as a dominant feature of any research in the regional economy; the imperative of any study that claims to belong to a regional economy is not only to establish general patterns of development and organization of economic life in the territory, but also the identification of its regional (local) specific

The Effect of Simultaneous Homo- and Heterogeneous Doping on Transport Properties of Ba2In2O5

In this article, the possibility of application of simultaneous homogeneous and heterogeneous doping has been described for the first time. The composite 0.7Ba1.95In2O4.9F0.1⋅0.3Ba2 InNbO6 has been obtained by in situ solid-state method. The scanning electron microscopy and thermogravimetry investigations have beencarried out; the electrical properties have been examined. It has been proved that simultaneous homogeneous and heterogeneous doping is a prospective method for obtaining high-conductive proton electrolytes. Keywords: brownmillerite, composite, anionic doping, fluorin

Synthesis, Hydration Processes and Ionic Conductivity of Novel Gadolinium-Doped Ceramic Materials Based on Layered Perovskite BaLa2In2O7 for Electrochemical Purposes

The search for novel highly effective materials with target properties for different electrochemical purposes is active for now. Ceramic materials with high levels of ionic conductivity can be applied as electrolytic materials in solid oxide fuel cells and in electrolyzers. Layered perovskites are a novel class of ionic conductors demonstrating almost-pure proton transportation at mid-temperatures. Gadolinium-doped ceramic materials based on layered perovskite BaLa2In2O7 were obtained and investigated for the first time in this study. The effect of the dopant concentrations on the hydration processes and on ionic conductivity was revealed. It was shown that compositions 0 ≤ x ≤ 0.15 of BaLa2–xGdxIn2O7 exhibited proton conductivity when under wet air and at mid-temperatures (lower than ~450 °C). Gadolinium doping led to an increase in the conductivity values up to an order of magnitude of ~0.5. The protonic conductivity of the most conductive composition BaLa1.85Gd0.15In2O7 was 2.7∙10−6 S/cm at 400 °C under wet air. The rare earth doping of layered perovskites is a prospective approach for the design of ceramics for electrochemical devices for energy applications. © 2022 by the authors

ELECTROLYTES BASED ON β"-Al2O3

The main problem of Li-ion batteries is their instability. To eliminate this drawback, we need to find an alternative to Li. Mg is a metal that attracts attention with its high exchange capacity and low cost compared to lithium. In our work, as a basis for solid electrolyte, we took a high-conductivity matrix of Na-β"-alumina stabilized by MgO. Ion exchange was used to synthesize Mg-β"-alumina. The structure and electrical properties of the samples were studied