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Silicon powder kerf loss from diamond wire sawing in the photovoltaic wafering industry is a highly appealing source material for use in lithium‐ion battery negative electrodes. Here, it is demonstrated for the first time that the kerf particles from three independent sources contain ~50 % amorphous silicon. The crystalline phase is in the shape of nano‐scale crystalline inclusions in an amorphous matrix. From literature on wafering technology looking at wafer quality, the origin and mechanisms responsible for the amorphous content in the kerf loss powder are explained. In order to better understand for which applications the material could be a valuable raw material, the amorphicity and other relevant features are thoroughly investigated by a large amount of experimental methods. Furthermore, the kerf powder was crystallized and compared to the partly amorphous sample by operando X‐ray powder diffraction experiments during battery cycling, demonstrating that the powders are relevant for further investigation and development for battery applications. [ABSTRACT FROM AUTHOR]

Despite significant potential as energy storage materials for electric vehicles due to their combination of high energy density per unit cost and reduced environmental and ethical concerns, Co‐free lithium ion batteries based on layered Mn oxides presently lack the longevity and stability of their Co‐containing counterparts. Here, a reduction in this performance gap is demonstrated via chemical doping, with Li1.1Ni0.35Mn0.54Al0.01O2 achieving an initial discharge capacity of 159 mAhg−1 at C/3 rate and a corresponding capacity retention of 94.3% after 150 cycles. The nanoscale origins of this improvement are subsequently explored through a combination of advanced diffraction, spectroscopy, and electron microscopy techniques, finding that optimized doping profiles lead to an improved structural and chemical compatibility between the two constituent sub‐phases that characterize the layered Mn oxide system, resulting in the formation of unobstructed lithium ion pathways between them. A structural stabilization effect of the host compound is also directly observed near the surface using aberration corrected scanning transmission electron microscopy and integrated differential phase contrast imaging. [ABSTRACT FROM AUTHOR]

The intermetallic compound ZnSb is a (II‐V) narrow gap semiconductor with interesting thermoelectric properties. Electrical resistivity, Hall coefficient, thermopower and thermal conductivity were measured up to 400 K on Ag‐doped samples with concentrations 0.2, 0.5, 1, 2, and 3 at.%, which were consolidated to densities in excess of 99.5 % by spark plasma sintering. The work confirms a huge improvement of the thermoelectric Figure‐of‐merit, ZT, upon Ag doping. The optimum doping level is near 0.5 at.% Ag and results in ZT values around 1.05 at 390 K. The improvement stems from a largely decreased resistivity, which in turn relates to an increase of the hole charge carrier concentration by two orders of magnitude. It is argued that Ag can replace minute concentrations of Zn (on the order of 0.2 at.%) in the crystal structure which enhances the intrinsic impurity band of ZnSb. Excess Ag was found to segregate in grain boundaries. So the best performing material may be considered as a composite Zn~0.998Ag~0.002Sb/Ag~0.003. [ABSTRACT FROM AUTHOR]

High‐temperature characterization of oxygen‐deficient Sr‐rich (La1–xSrx)2NiO4–δ (x = 0.5–0.8) solid solutions under mildly reducing conditions with p(O2) ≈ 5 × 10–5 atm was performed by employing structural and thermal analysis, TEM, and electrical conductivity measurements. Oxygen losses from the crystal lattice on reduction were found to result in a reversible transition from the tetragonal (I4/mmm) to the orthorhombic (Immm) structure and shrinkage of the crystal lattice for the compositions with x > 0.5. TEM and thermogravimetric analysis evidenced slow kinetics of the structural transition. The increase in oxygen deficiency under reducing conditions is accompanied by localization of the electronic charge carriers, a drop of the p‐type electronic conductivity, and a transition from metallic‐like to semiconducting behavior. The extent of changes in oxygen nonstoichiometry, unit‐cell dimensions, average Ni oxidation state, electron–hole concentration, and electronic conductivity on reduction is interrelated with the strontium content. The results suggest that the electrical conductivity of (La1–xSrx)2NiO4–δ ceramics depends mainly on the average Ni oxidation state. [ABSTRACT FROM AUTHOR]

The structures of Ruddlesden–Popper n = 2 member phases Sr3−xYxFe1.25Ni0.75O7−δ with 0 ≤x≤ 0.75 have been investigated using neutron powder diffraction and K-edge Fe and Ni EXAFS/XANES spectroscopy in order to gain information about the evolution of the oxygen vacancy distribution and Fe/Ni oxidation state with x. Both samples prepared at 1300 °C under a flow of N2(g), with δ = 1.41–1.00, and samples subsequently annealed in air at 900 °C, with δ = 0.44–0.59, were characterized. The as-prepared x = 0.75 phase has δ = 1, the O1 atom site is vacant, and the Fe3+/Ni2+ ions have a square pyramidal coordination. With decreasing x the O3 occupancy decreases nearly linearly to 81% for x = 0, while the O1 occupancy increases from 0 for x = 0.4 to 33% for x = 0. The air-annealed x = 0.75 sample has a δ value of 0.59 and the Fe3+/Fe4+/Ni2+/Ni3+ ions have both square pyramidal and octahedral coordination. With decreasing x, the δ value decreases to 0.45 for x = 0, implying an increase in the oxidation states of Fe/Ni ions. EXAFS/XANES data show that for the as-prepared samples the coordination changes are predominantly for Ni2+ ions and that the air-annealed samples contain both Fe3+/Fe4+ and Ni2+/Ni3+ ions. [ABSTRACT FROM AUTHOR]

An experimental setup and routine is presented for evaluating potential catalysts for water splitting by means of measuring the faradaic efficiency in real time through coupled potentiometry and mass spectrometry. The aim was to scale up an analytical cell unit towards the simulation of industrial conditions and generate results such as H2 production versus power input at a certain potential or current density in addition to electrochemical parameters. Three types of electrodes were tested: A) planar metal electrodes; B) metal-foam-based electrodes; C) porous electrodes with carbon additive. The results verify that the experimental routine yields the desired accuracy, sensitivity, and a negligible accumulation of gaseous products in the cell; thus the faradaic efficiency is measured in real time. The metal-based electrodes of category A and B proved to be durable with low overpotentials and high gas output to power input, whereas three tested metal oxide electrodes in C revealed i) potential-dependent deviation in the faradaic efficiency, ii) phase decomposition, and iii) an optimum operational power range. [ABSTRACT FROM AUTHOR]

The kinetics of thermal dehydration of KCu[Fe(CN)]· nHO was studied using thermogravimetry for x = 0.0 and 1.0. Data from both non-isothermal and isothermal measurements were used for model-free kinetic analysis by the Friedman and KAS methods. The water content was determined to be n = 2.9-3.9, plus an additional ~10% of water, likely surface adsorbed, that leaves very fast when samples are exposed to a dry atmosphere. The determined average activation energy for 0.2 ≤ α ≤ 0.8 is 56 kJ mol. The dehydration is adequately described as a diffusion-controlled single-step reaction following the D3 Jander model. The determined dehydration enthalpy is 11 kJ (mol HO) for x = 0.0 and 27 kJ (mol HO) for x = 1.0, relative to that of water. The increase with increasing x is evidence that the HO molecules form bonds to the incorporated K ions. [ABSTRACT FROM AUTHOR]

Perovskite-related (La1− xSr x)2NiO4− δ ( x=0.5-0.8) phases were explored for possible use as oxygen electrodes in solid electrolyte cells with a main focus on the effect of oxygen deficiency on the electrocatalytic activity. (La1− xSr x)2NiO4− δ solid solutions were demonstrated to preserve the K2NiF4-type tetragonal structure under oxidizing conditions. Acceptor-type substitution by Sr is compensated by the formation of oxygen vacancies and electron holes and progressively increases high-temperature oxygen nonstoichiometry, which reaches as high as δ=0.40 for x=0.8 at 950 °C in air. The electrical conductivity of (La1− xSr x)2NiO4− δ ceramics at 500-1000 °C and p(O2)≥10−3 atm is p-type metallic-like. The highest conductivity, 300 S cm−1 at 800 °C in air, is observed for x=0.6. The average thermal expansion coefficients, (14.0-15.4)×10−6 K−1 at 25-900 °C in air, are sufficiently low to ensure the thermomechanical compatibility with common solid electrolytes. The polarization resistance of porous (La1− xSr x)2NiO4− δ electrodes applied on a Ce0.9Gd0.1O2− δ solid electrolyte decreases with increasing Sr concentration in correlation with the concentration of oxygen vacancies in the nickelate lattice and the anticipated level of mixed ionic-electronic conduction. However, this is accompanied by increasing reactivity between the cell components and necessitates the microstructural optimization of the electrode materials to reduce the electrode fabrication temperature. [ABSTRACT FROM AUTHOR]

Two electrodes for anodic water oxidation made by direct synthesis of inorganic catalysts onto conductive carbon fibre sheets are evaluated. As catalysts two Co- and Sb-containing phases were tested, that is, Co3Sb4O6F6 and the new compound CoSbO4. The compounds express large differences in their morphology: CoSbO4 grows as thin needles whereas Co3Sb4O6F6 grows as larger facetted crystals. Despite the smaller surface area the latter compound shows a better catalytic performance. When the compound Co3Sb4O6F6 was used it gave a low increase of +0.028 mV h−1 at an overpotential of η=472 mV after 10 h and a stability of +0.48 mV h−1 at an overpotential of η=488 mV after 60 h. The leakages of Co and Sb were negligible and only <0.001 at % Co and approximately 0.02 at % Sb were detected in the electrolyte. [ABSTRACT FROM AUTHOR]

Previously unexplored oxygen-deficient Ruddlesden–Popper Nd2−xSrxNiO4−δ (x = 1.0–1.6) nickelates were evaluated for potential use as oxygen electrode materials for solid oxide fuel and electrolysis cells, with emphasis on structural stability, oxygen nonstoichiometry, dimensional changes, and electrical properties. Nd2−xSrxNiO4−δ ceramics possess the K2NiF4-type tetragonal structure under oxidizing conditions at 25–1000 °C. Acceptor-type substitution by strontium is compensated by the generation of electron–holes and oxygen vacancies. Oxygen deficiency increases with temperature and strontium doping reaching ∼1/8 of oxygen sites for x = 1.6 at 1000 °C in air. Strongly anisotropic expansion of the tetragonal lattice on heating correlated with oxygen nonstoichiometry changes results in an anomalous dilatometric behavior of Nd2−xSrxNiO4−δ ceramics under oxidizing conditions. Moderate thermal expansion coefficients, (11–14) × 10−6 K−1, ensure however thermomechanical compatibility with common solid electrolytes. Reduction in inert atmosphere induces oxygen vacancy ordering accompanied by a contraction of the lattice and a decrease of its symmetry to orthorhombic. Nd2−xSrxNiO4−δ ceramics exhibit a p-type metallic-like electrical conductivity at 500–1000 °C under oxidizing conditions, with the highest conductivity (290 S cm−1 at 900 °C in air) observed for x = 1.2. The high level of oxygen deficiency in Sr-rich Nd2−xSrxNiO4−δ implies enhanced mixed ionic–electronic transport favorable for electrode applications. [ABSTRACT FROM AUTHOR]

Many features of aluminosilicate glasses incorporating a rare-earth ( RE) ion are dictated by its mass and cation field strength ( CFS). Sc- Al- Si- O glasses are interesting because Sc3+ exhibits the highest CFS but the lowest mass of all RE3+ ions. We explore relationships between the glass composition and several physical properties, such as density, glass-transition temperature ( Tg), Vickers hardness, and refractive index, over the glass forming region of the ternary Sc2 O3- Al2 O3- SiO2 system. The glasses exhibit uniform and unexpectedly low Tg-values (≈875°C), but a high microhardness (≈9.3 GPa) that correlates with the Sc2 O3 content. 29 Si magic-angle spinning ( MAS) nuclear magnetic resonance ( NMR) spectroscopy shows enhanced deshielding and a minor glass-network ordering as either the Al or Sc content of the glass increases. 27 Al MAS NMR reveals that besides the expected AlO4 tetrahedra, substantial amounts of AlO5 (31%-35%) and AlO6 (≈5%) polyhedra are present in all Sc- Al- Si- O glass structures. 45 Sc isotropic chemical shifts (≈92 ppm) derived from MAS and 3 QMAS (triple-quantum MAS) NMR experiments are consistent with ScO6 environments. [ABSTRACT FROM AUTHOR]

We report the glass-forming regions of the ternary Lu2O3-Al2O3-SiO2 and Sc2O3-Al2O3-SiO2 systems. The density, molar volume, compactness, Vickers hardness, refractive index, as well as the glass transition ( Tg) and crystallization temperature are compared for two series of RE-Al-Si-O (RE=La, Y, Lu, Sc) glasses that display a constant molar ratio nAl/ nSi=1.00, whereas nRE/ nSi is equal to either 0.62 or 0.94. Several glass properties scale roughly linearly with the cation field strength (CFS) of the rare-earth (RE3+) ion, except for the Tg values of the Sc-bearing glasses that are significantly lower than expected. Magic-angle spinning 29Si and 27Al nuclear magnetic resonance (NMR) reveal enhanced network disorder and increased relative populations of AlO5 and AlO6 polyhedra in the aluminosilicate glasses for increasing RE3+ CFS, but overall similar Si and Al local environments (chemical shifts and quadrupolar couplings) in all samples associated with a constant nRE/ nSi ratio, except for unexpectedly shielded 29Si NMR signals observed from the Sc-Al-Si-O glasses. [ABSTRACT FROM AUTHOR]

Glass formation in the system Sr–Si–O–N was investigated and properties of obtained glasses evaluated. The glass-forming region was determined for glasses prepared by melting mixtures of Sr metal, SiO2 and Si3N4 powders in Nb crucibles at 1600–1750 °C in nitrogen atmosphere using a radio frequency furnace. The glasses were found to be homogenous, translucent gray to opaque black, and to contain high contents of N (up to 45 e/o) and Sr (up to 36 e/o). The glass transition temperature (790–973 °C), density (2.99–4.07 g/cm3), microhardness (8.10–10.50 GPa), and refractive index (1.65–1.93) are strongly correlated with the amounts of Sr and N. The properties are compared with findings in other oxynitride silicate glass systems. [ABSTRACT FROM AUTHOR]

In developing elongated α-sialon grains, a nitrogen-rich liquid phase sintering method was introduced by using CaH2 as a sintering aid, so as to vary the N/O ratio of the liquid phase formed in the sintering process while keeping the Si/Al ratios constant. With increasing addition the phase contents changed from single β-sialon to dual β/α-sialons and to single Ca-α-sialon. At low N/O ratios the microstructures contained mainly equiaxed β-sialon grains, and at high N/O ratios well faceted elongated Ca-α-sialon grains. The improved toughness ( KI C=7.8 MPa·m1/2) and hardness ( HV10=17.5 GPa) properties can be attributed to the formation of interlocked microstructures. High-temperature compressive deformation tests indicated that the deformation onset temperature is determined mainly by the Si/Al and N/O ratios, whereas the deformation rate is affected by the microstructure, i.e., the morphology and amounts of elongated α-sialon grains and residual glass phase, especially for the sialons with low N/O ratios. [ABSTRACT FROM AUTHOR]

Nitrogen-rich Ca–α-SiAlON ceramics with nominal compositions Ca xSi12−2 xAl2 xN16 and 0.2≤ x≤2.6, extending along the Si3N4–1/2Ca3N2:3AlN tie line, were prepared from Si3N4, AlN, and CaH2 precursors by hot pressing at 1800°C. The x values attained were determined by energy-dispersive X-ray (EDX) microanalysis and X-ray powder diffraction (XRPD) data using the Rietveld method. The results show that Ca–α-SiAlONs form continuously within the compositional range x=0 to at least x=1.82. Phase assemblages, lattice parameters, Vickers hardness, and fracture toughness were determined and correlated to the calcium content, x. Owing to a high sintering temperature and the use of CaH2 as a precursor, grain growth was kinetically enhanced, resulting in self-reinforced microstructures with elongated grains. The obtained Ca–α-SiAlON ceramics demonstrate a combination of both high hardness ∼21 GPa, and high fracture toughness ∼5.5 MPa·m1/2. [ABSTRACT FROM AUTHOR]

Single crystals of the nitridosilicate Ca[sub 0.27]La[sub 0.03]Si[sub 11.38]Al[sub 0.62]N[sub 16] with a filled α-Si[sub 3]N[sub 4]-type structure were obtained when preparing lanthanum nitridosilicates in a graphite furnace accidentally containing calcium residues. The lithium α-SiAlON LiSi[sub 9]Al[sub 3]O[sub 2]N[sub 14] was prepared using spark plasma sintering, with the sample containing in addition a β-SiAlON, LiAlSiO[sub 4], and a glass phase. The structure of Ca[sub 0.27]La[sub 0.03]Si[sub 11.38]Al[sub 0.62]N[sub 16] was refined using MoKα single-crystal data, in space group P31c with a = 7.838(1), c = 5.703(1) Å, V = 303.4 Åsup3;, to a weighted R(F[sup 2, sub obs]) = 6.0% for 475 unique reflections. The isotypic structure of LiSi[sub 9]Al[sub 3]O[sub 2]N[sub 14] was refined with anisotropic thermal parameters and a = 7.8277(2), c = 5.6909(2) Å to R[sub F] = 0.63 % for 849 reflections for d ≥ 0.5 Å using time-offlight (TOF) neutron powder diffraction (NPD) data. The SiX[sub 4] (X = N or N/O) tetrahedra are regular in booth structures, with Si-N distances of 1.745(1) - 1.785(3) Å for the calciumlanthanum compound and 1.741(1) - 1.765(1) Å for the lithium compound. The Ca/La and lithium atoms are located on the 2b position, (1/3, 2/3, z), coordinated by seven anions with the shortest metal-anion distances of 2.38(1) and 2.05(2) Å, respectively. The lithium atoms are displaced ∼0.28 Å relative to the position of the Ca/La atoms, and the lithium atoms can alternatively be described as tetrahedrally coordinated. [ABSTRACT FROM AUTHOR]

The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energy-dispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, ~3.3 molecules of CO2 at 20 °C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, ~3.8 mmol/g at 20 °C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations. [ABSTRACT FROM AUTHOR]

Compounds Sr3−xPrxFe1.25Ni0.75O7−δ with 0 ≤ x ≤ 0.4 and Ruddlesden–Popper n = 2 type structures were synthesized and investigated by X-ray and neutron powder diffraction, thermogravimetry, and Mössbauer spectroscopy. Both samples, prepared at 1300 °C under N2(g) flow and samples subsequently air-annealed at 900 °C, were studied. The structures contained oxygen vacancies in the perovskite layers, and the Fe/Ni cations had an average coordination number less than six. The oxygen content was considerably higher for air-annealed samples than for samples prepared under N2, 7 − δ = ~6.6 and ~5.6 per formula unit, respectively. Mössbauer data collected at 7 K, below magnetic ordering temperatures, were consistent with X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) results. The electrical conductivity was considerably higher for the air-annealed samples and was for x = 0.1~30 S·cm−1 at 500 °C. The thermal expansion coefficients were measured in air between room temperature and 900 °C and was found to be 20–24 ppm·K−1 overall. [ABSTRACT FROM AUTHOR]

Water Splitting Catalytic water splitting is a very active research field, and many organic and inorganic catalysts have been tested for the oxidation reaction that is more challenging to catalyse at a low overpotential than the reduction reaction. Metalorganic catalysts most often survive only for short time period, so inorganic compounds are in general more promising. Several promizing oxide compounds containing cobalt have previously been identified and studied. To investigate direct synthesis of catalytically active compounds and their long time behavior, H. Svengren et al. have synthesized crystals of Co3Sb4O6F6 and the new compound CoSbO4 directly onto carbon electrodes. In their Full Paper on page 568 ff., they show the importance of making long‐term stability tests when ranking the performance of different catalysts. [ABSTRACT FROM AUTHOR]

Here we demonstrate how monodisperse iron oxide nanocubes and nanospheres with average sizes between 5 and 27 nm can be synthesized by thermal decomposition. The relative importance of the purity of the reactants, the ratio of oleic acid and sodium oleate, the maximum temperature, and the rate of temperature increase, on robust and reproducible size and shape-selective iron oxide nanoparticle synthesis are identified and discussed. The synthesis conditions that generate highly monodisperse iron oxide nanocubes suitable for producing large ordered arrays, or mesocrystals are described in detail. [ABSTRACT FROM AUTHOR]