Композиционные силикатные краски с улучшенными технологическими сойствами

The composition of one-packing silicate paint on the basis of liquid glass modified by acrylic dispersion in number of 5%, including inactive filler in number of 15% in the form of talc and chalk, zinc oxide ranging from 5 to 9% as a hardener, and an active silica component which contents changes depending on its nature was developed. Liquid glass compositions with usage of aerosol and activated quartz sand was received. They improved characteristics and increased viability approximately to one year

KFe(C2O4)F : a fluoro-oxalate cathode material for Li/Na-ion batteries

Funding: The authors want to thank EPSRC (EP/R030472/1) and the Faraday Institution (FIRG018) for their financial support. In addition, AGM wishes to thank the Faraday Institution for financial support and training (Grant number FITG033). The authors also thank EPSRC Light Element Analysis Facility Grant EP/T019298/1 and the EPSRC Strategic Equipment Resource Grant EP/R023751/1.The iron-based polyanionic fluoro-oxalate material, KFe(C2O4)F (KFCF), has been synthesized by hydrothermal methods. This compound shows promising reversible lithium and sodium insertion properties as a cathode material. The material delivered a first-cycle discharge capacity of 120 mAh g-1 at ∼3.3 V (Li+/Li) and 97.4 mAh g-1 at ∼3.0 V (Na+/Na) in LIB and NIB, respectively. Stable cycling performance was observed in both cases. The involvement of reversible Fe2+/Fe3+ redox was confirmed by ex-situ Mössbauer spectroscopy supported by first-principles calculations. This study reveals promising performance from a mixed oxalate-fluoride based polyanionic material thereby opening up further possibilities for materials discovery in the design of new electrode materials.Publisher PDFPeer reviewe

Effects of Relaxation on Conversion Negative Electrode Materials for Li-Ion Batteries: A Study of TiSnSb Using 119Sn Mössbauer and 7Li MAS NMR Spectroscopies

Conversion materials were recently considered as plausible alternatives to conventional insertion negative electrode materials in lithium-ion batteries due to their large gravimetric and volumetric energy densities. The ternary alloy TiSnSb was recently proposed as a suitable negative electrode material due to its large capacity (550 mA h g–1) and rate capability over many cycles. TiSnSb has been investigated at the end of lithiation (discharge) using 119Sn Mössbauer and 7Li magic-angle spinning (MAS) NMR spectroscopies to determine the species formed, their relative stabilities and their behavior during relaxation. During discharge, TiSnSb undergoes a conversion reaction to produce a mixture of phases believed to consist of lithium antimonides, lithium stannides, and titanium metal. In situ 119Sn Mössbauer spectroscopy indicates the presence of Li7Sn2 at the end of discharge, while 7Li NMR experiments suggest the formation of two distinct Sn-containing species (tentatively assigned to Li7Sn2 and Li7Sn3), in addition to two Sb-containing species (tentatively assigned as Li3Sb and a non-stoichiometric phase of Li2Sb, Li2–xSb). To gain insight into the relative stabilities of the species formed, experiments have been completed under open circuit voltage conditions. A new Sn-based species has been identified via 119Sn Mössbauer spectroscopy at the end of relaxation. Similar changes are observed in the 7Li NMR spectra obtained during relaxation. The species created at the end of discharge are extremely unstable and spontaneously evolve towards delithiated phases. Surprisingly, it is possible to resume electrochemical cycling after relaxation. It is likely that this behavior can be extended to this family of electrode materials that undergo the conversion reaction

Slow Magnetic Relaxation and Electron Delocalization in an S = 9/2 Iron(II/III) Complex with Two Crystallographically Inequivalent Iron Sites

The magnetic, electronic, and Mössbauer spectral properties of Fe 2L(µ-OAc)2ClO4, 1, where L is the dianion of the tetraimino-diphenolate macrocyclic ligand, H2L, indicate that 1 is a class III mixed valence iron(II/III) complex with an electron that is fully delocalized between two crystallographically inequivalent iron sites to yield a [Fe2]V cationic configuration with a St 9/2 ground state. Fits of the dc magnetic susceptibility between 2 and 300K and of the isofield variable-temperature magnetization of 1 yield an isotropic magnetic exchange parameter, J, of -32(2) cm-1 for an electron transfer parameter, B, of 950 cm-1, a zero-field uniaxial D9/2 parameter of -0.9(1) cm-1, and g 1.95(5). In agreement with the presence of uniaxial magnetic anisotropy, ac susceptibility measurements reveal that 1 is a single-molecule magnet at low temperature with a single molecule magnetic effective relaxation barrier, Ueff, of 9.8 cm-1. At 5.25 K the Mössbauer spectra of 1 exhibit two spectral components, assigned to the two crystallographically inequivalent iron sites with a static effective hyperfine field; as the temperature increases from 7 to 310 K, the spectra exhibit increasingly rapid relaxation of the hyperfine field on the iron-57 Larmor precession time of 5 x 10-8 s. A fit of the temperature dependence of the average effective hyperfine field yields |D9/2| 0.9 cm-1. An Arrhenius plot of the logarithm of the relaxation frequency between 5 and 85 K yields a relaxation barrier of 17 cm-1

In-Depth Analysis of the Conversion Mechanism of TiSnSb vs Li by Operando Triple-Edge X-ray Absorption Spectroscopy: a Chemometric Approach

The electrochemical cycling mechanism of the ternary intermetallic TiSnSb, a promising conversion-type negative electrode material for lithium batteries, was thoroughly studied by operando X-ray absorption spectroscopy (XAS) at three different absorption edges, i.e., Ti, Sn, and Sb K-edge. Chemometric tools such as principal component analysis and multivariate curve resolution-alternating least squares were applied on the extensive data set to extract the maximum contained information in the whole set of operando data. The evolution of the near-edge (XANES) fingerprint and of the extended fine-structure (EXAFS) of the XAS spectra confirms the reversibility of the conversion mechanism, revealing that Ti forms metallic nanoparticles upon lithiation and binds back to both Sn and Sb upon the following delithiation. The formation of both Li7Sn2 and Li3Sb upon lithiation was also clearly confirmed. The application of chemometric tools allowed the identification of a time shift between the reaction processes of Sn and Sb lithiation, indicating that the two metals do not react at the same time, in spite of a certain overlap between their respective reaction. Furthermore, XANES and EXAFS fingerprint show that the Ti–Sn–Sb species formed after one complete lithiation/delithiation cycle is distinct from the starting material TiSnSb

Phase transitions in LaFeAsO: structural, magnetic, elastic, and transport properties, heat capacity and Mossbauer spectra

We present results from a detailed experimental investigation of LaFeAsO, the parent material in the series of "FeAs" based oxypnictide superconductors. Upon cooling this material undergoes a tetragonal-orthorhombic crystallographic phase transition at ~160 K followed closely by an antiferromagnetic ordering near 145 K. Analysis of these phase transitions using temperature dependent powder X-ray and neutron diffraction measurements is presented. A magnetic moment of ~0.35 Bohr magnetons per iron is derived from Mossbauer spectra in the low temperature phase. Evidence of the structural transition is observed at temperatures well above the structural transition (up to near 200 K) in the diffraction data as well as the polycrystalline elastic moduli probed by resonant ultrasound spectroscopy measurements. The effects of the two phase transitions on the transport properties (resistivity, thermal conductivity, Seebeck coefficient, Hall coefficient), heat capacity, and magnetization of LaFeAsO are also reported, including a dramatic increase in the magnitude of the Hall coefficient below 160 K. The results suggest that the structural distortion leads to a localization of carriers on Fe, producing small local magnetic moments which subsequently order antiferromagnetically upon further cooling. Evidence of strong electron-phonon interactions in the high-temperature tetragonal phase is also observed.Comment: Revised and expanded magnetization and Mossbauer spectroscopy section. Clarified sample preparation description. This paper contains some results from arXiv:0804.0796. 10 figure

2021 roadmap for sodium-ion batteries

Abstract: Increasing concerns regarding the sustainability of lithium sources, due to their limited availability and consequent expected price increase, have raised awareness of the importance of developing alternative energy-storage candidates that can sustain the ever-growing energy demand. Furthermore, limitations on the availability of the transition metals used in the manufacturing of cathode materials, together with questionable mining practices, are driving development towards more sustainable elements. Given the uniformly high abundance and cost-effectiveness of sodium, as well as its very suitable redox potential (close to that of lithium), sodium-ion battery technology offers tremendous potential to be a counterpart to lithium-ion batteries (LIBs) in different application scenarios, such as stationary energy storage and low-cost vehicles. This potential is reflected by the major investments that are being made by industry in a wide variety of markets and in diverse material combinations. Despite the associated advantages of being a drop-in replacement for LIBs, there are remarkable differences in the physicochemical properties between sodium and lithium that give rise to different behaviours, for example, different coordination preferences in compounds, desolvation energies, or solubility of the solid–electrolyte interphase inorganic salt components. This demands a more detailed study of the underlying physical and chemical processes occurring in sodium-ion batteries and allows great scope for groundbreaking advances in the field, from lab-scale to scale-up. This roadmap provides an extensive review by experts in academia and industry of the current state of the art in 2021 and the different research directions and strategies currently underway to improve the performance of sodium-ion batteries. The aim is to provide an opinion with respect to the current challenges and opportunities, from the fundamental properties to the practical applications of this technology

Fourier transform infrared spectroscopic study of abhurite Sn21O6Cl16(OH)(14)

Abhurite Sn21O6Cl16(OH)(14) is a tin oxy-hydroxychloride discovered in 1985 as a tin corrosion product formed after long immersion in seawater, has been synthesised and studied using FTIRAS analysis. The vibrational spectra obtained in transmission and reflectance modes of analysis are presented and compared to the vibrational spectra determined by Kramers-Kronig analysis. Transversal and longitudinal (TO and LO) optical modes have been identified. (c) 2007 Elsevier B.V. All rights reserved

Local ordering and magnetism in Ga0.9Fe3.1N

Prior investigations of the ternary nitride series Ga1-xFe3+xN (0 <= x 1) have indicated a transition from ferromagnetic gamma'-Fe4N to antiferromagnetic ``GaFe3N''. The ternary nitride ``GaFe3N'' has been magnetically and spectroscopically reinvestigated in order to explore the weakening of the ferromagnetic interactions through the gradual incorporation of gallium into gamma'-Fe4N. A hysteretic loop at RI reveals the presence of a minority phase of only 0.1-0.2 at\%, in accord with the sound two-step synthesis. The composition of the gallium-richest phase ``GaFe3N'' was clarified by Prompt Gamma-ray Activation Analysis and leads to the berthollide formula Ga0.91(1)Fe3.09(10)N1.05(7). Magnetic measurements indicate a transition around 8 K, further supported by Mossbauer spectral data. The weakening of the ferromagnetic coupling through an increasing gallium concentration is explained by a simple Stoner argument. In Ga0.9Fe3.1N the presence of iron on the gallium site affects the magnetism by the formation of 13-atom iron clusters. (C) 2011 Elsevier Inc. All rights reserved