Low Temperature Solid State Research Articles

Synthesis of a Sodium-Ion Cathode Material Na3Fe2(SO4)3F with the Help of Fluorine Element.

The development of cathode materials has always been one of the most crucial areas of research in the field of sodium-ion batteries. Sulfate-based polyanionic materials, known for their high working voltage characteristics, have received widespread attention. In this work, a fluoro-sulfate sodium-ion battery cathode material, Na3Fe2(SO4)3F modified with carbon nanotubes, was developed using a low-temperature solid-state annealing method. This Na3Fe2(SO4)3F cathode exhibits an exceptionally high voltage of 3.77 V, excellent discharge capacity (102 mAh/g at 0.1C), and good rate capability. This material broadens the research directions for cathode materials and holds promise as a foundation for the further development of high-performance sodium-ion batteries.

Effect of Sm3+ ions doping on the structural and optical properties, Judd-Ofelt and radiative parameters of ZnS phosphor materials

Undoped ZnS and Sm3+ doped with varying concentration of ZnS phosphor materials were synthesized via low temperature solid state reaction method. The samples were investigated for the influence of different concentrations of Sm3+ ions on their structural and spectroscopic properties. The presence of various absorption bands in UV–Vis–NIR spectra revealed the transition from ground state to different excited states of Sm3+ ions. The Judd-Ofelt (JO) analyses were evaluated to identify the structure and the bonding around the Sm3+ ions. The high value of Ω2 intensity parameter reveals that the site symmetry is lower. The parameters such as radiative transition probabilities, radiative lifetime, branching ratio, stimulated emission cross-sections and the optical gain parameters are also evaluated. The PL spectra shows five high intensity emission bands centered at 567 nm, 590 nm, 619 nm, 641 nm and 667 nm corresponding to 4G5/2→6Hj (j = 5/2, 7/2,9/2, 11/2, 13/2) transitions and showed optimum for concentration at x = 0.03 in Zn(1-x)S. The quantum yield of the prepared optimal phosphor using integrating sphere method was found to be 10.08%. This indicates that the materials synthesized may be favorable for the applications of laser and other optical devices.

Low-temperature one-step solid state chemical synthesis of GaN nanosheets for conquering polysulfides in Li–S battery

Gallium nitride (GaN) nanosheets have been prepared as an active material for conquering polysulfides in Lithium–Sulfur (Li–S) batteries via one simple synthetic route at 550 °C. The process was carried out in a stainless steel autoclave by using gallium nitrate hydrate, sodium amide and metallic lithium as starting materials. The product was proven to be hexagonal GaN nanosheets by combined X-ray powder diffraction (XRD) pattern and Scanning electron microscopy (SEM). The GaN nanosheets were then used to coat on the Li–S battery separator, and the result proves an effective inhibition of the shutting problem and gives excellent electrochemical properties compared with traditional separators or GaN additives. The battery assembled by GaN coated separator shows good cycling stability with 408 mAh/g and a low capacity fading of 0.6‰ per cycle from 11th to 480th cycle at 2 C due to high utilization of the sulfur-based active species.

Influence of carbon layer thickness on the Li-ion storage property of [002]-oriented β-Li2TiO3@C nanowires

Monoclinic Li2TiO3 (β-Li2TiO3) is a kind of potential candidate for anodic material of high-safety lithium-ion batteries (LIBs) for its stable zero-strain layered structure; however, β-Li2TiO3 has intermediate Li+ ​ion conductivity and low electronic conductivity, affecting its practical application. Herein, [002]-oriented β-Li2TiO3@C nanowires have been synthesized via a convenient low-temperature solid state method. The diffusion of Li+ ​along the ab plane of β-Li2TiO3 has relatively low energy barrier, and the obtained [002]-oriented nanowires (with diameter of 50–70 ​nm) provide short and accessible Li+ ​diffusion pathways along the ab plane. In addition, the modification of carbon layers with optimal thickness (∼8 ​nm) can promote the Li+ transfer kinetics and improve the electronic conductivity. As a result, [002]-oriented β-Li2TiO3@C nanowires exhibit excellent electrochemical performance, involving high specific capacity (243.1 mAh g−1 at 50 ​mA ​g−1), high rate capability (173.6 and 155.3 mAh g−1 at current rates of 50 and 200 ​mA ​g−1), and good cyclic stability (160.9 mAh g−1 at 50 ​mA ​g−1 after 100 cycles). Therefore, [002]-oriented β-Li2TiO3@C nanowires have the potential to be used as anodic material for high-performance LIBs. This work could provide inspiration to improve the Li-ion storage property of anodic materials by purposely tailoring the structure and crystal orientation.

In air solid state method to prepare Zr4+ doped SnS2 with increased photocatalytic activity

• In air low temperature (180 °C) solid state preparation of Zr-SnS 2 . • Zr-SnS 2 comprises nanoflake aggregates. • Zr-SnS 2 exhibits greater activity than SnS 2 in photocatalytic reduction of Cr(VI). • Reasons behind the improved photocatalytic efficiency of Zr-SnS 2 are suggested. SnS 2 is a potential visible-light photocatalyst, but its applications are restricted by its dissatisfactory photocatalytic efficiency and unpractical synthesis methods. Here, a practical solid state method was employed to prepare Zr 4+ doped SnS 2 (Zr-SnS 2 ) for use as a more efficient photocatalyst. By heating the mixed powders of SnCl 2 •2H 2 O, ZrCl 4 and thiourea in air atmosphere at 180 °C for 5 h, Zr-SnS 2 nanoflake aggregates were prepared. The as-prepared Zr-SnS 2 exhibited greater photocatalytic Cr(VI) reduction activity under visible-light irradiation, as compared with SnS 2 . The doping of Zr 4+ can reduce the bandgap, promote the photogenerated carrier separation and transfer, and increase the specific surface area and Cr(VI)-adsorbing capacity of SnS 2 , which contribute to the improved photocatalytic efficiency of Zr-SnS 2 . The simple and low-cost solid state method is promising for scale-up production of efficient Zr-SnS 2 photocatalyst for treating Cr(VI)-contaminated water.

Influence of LTSSR and HTSSR synthesis methods on the structural properties of YFeO3 orthoferrite

The YFO ceramics have been synthesized using High Temperature Solid State Reaction (HTSSR) as well as Low Temperature Solid State Reaction (LTSSR) technique in powder form. The Perovskite orthorhombic YFeO3 phase has been identified in the x-ray studies of the powder samples prepared with HTSSR technique. In addition, 24 % of Y2O3 phase is also detected in the HTSSR powder samples. This phase reduced with increasing calcination time, however could not be suppressed below 8 % even after calcination for 72 h. Whereas, the powder samples prepared using LTSSR technique exhibit only pure YFeO3 phase, on calcination at 950 °C for 6hrs.Therefore found a more convenient and less time-consuming technique for the development of the orthorhombic YFeO3phase in YFO ceramics.

Magnetic properties of α-KCoPO4 compound with a chiral polar crystal structure

We have obtained polycrystalline samples of a metastable α variant of KCoPO4 by low temperature (350–400 °C) solid state metathesis reaction of potassium oxalate and ammonium cobalt orthophosphate. The material crystallizes in a polar chiral structure (sg. P63, no. 173). Measurements of magnetic properties reveal antiferromagnetic interactions and no ordering observed down to T = 1.9 K, well below the Weiss temperature |Θcw| = 13.9 K.

Synthesis and conductivity of LiFePO4 and solid solutions LiFe1–xМxPO4 (M – Zn, Mg, Cu, x<0.2)

We studied the influence of reagents mixture composition on the formation of LiFePO4 under the conditions of low-temperature solid state synthesis by interaction of NH4FePO4 with molten LiCH3COO and by crystallization from nitrate melt. The interaction of the reagents mixture components was investigated for the systems NH4FePO42H2O–А (where А – LiNO3, Li2CO3, LiCH3COO) and FeC2O42H2O–(NH4)2HPO4)/NH4H2PO4–А (where А – Li2CO3, LiF). A stability of Fe(II) to oxidation under the synthetic conditions was established depending on the reaction mixtures composition. It was found that Fe(II) is the most stable to oxidation under the conditions of solid state synthesis from the system Li2CO3–FeC2O42H2O–(NH4)2HPO4)/NH4H2PO4. For the synthesized solid solutions with partial isovalent substitution of iron LiFe0.8M0.2PO4 (M – Mg, Cu), a unit cell volume, lattice parameters а and с and conductivity increase as compared with undoped LiFePO4, while the unit cell volume, the lattice parameters а and с and conductivity of LiFe0.8Zn0.2PO4 decrease. The obtained results indicate possibility to influence the electrical conductivity of materials based on LiFePO4 by isovalent substitution of iron.

Low Temperature Solid-State Bonding of Nickel and Tin with Formic Acid Surface Modifications

Low Temperature Solid-State Bonding of Nickel and Tin with Formic Acid Surface Modifications

Fluorine-free synthesis and characterization of vanadium-zircon (V–ZrSiO4) turquoise ceramic pigment by a low temperature solid state reaction route

A fluorine-free and low temperature synthetic route derived from in-situ formed mineralizer has been developed to fabricate V–ZrSiO4 turquoise ceramic pigment. When the calcination temperature is 750 °C and mole ratio of Na3VO4 to ZrOCl2·8H2O (NV/Zr) is 0.3, the as-prepared pigment exhibits a cluster-like structure and deep blue hue (L* = 69.28, a* = −12.15, b* = −20.04). The solid state reaction taking place during the mechanical grinding process lead to the in-situ formation of mineralizer NaCl and certain Si–O–Zr bond. The XRD refinement results and hyperfine structure in EPR spectra indicate that vanadium is located at the zircon interstitial site 16g with an isolated V4+ cluster state. The enameled samples exhibit excellent coloring ability, high chemical and thermal stability, suggesting its potential application in ceramic decoration.

Synthesis and characterization of Fe3-xSnxO4 (X = 0–0.5) soft magnetic materials by low-temperature solid state method

Tin-doped spinel has been reported as a classical soft magnetic material. In this study, series spinels of Fe3-xSnxO4 were synthesized via a novel low-temperature solid-state reaction process from natural magnetite and cassiterite. The substitution mechanisms between Sn4+ and Fe3+ were investigated by means of XRD, TEM, XPS, Mössbauer, FT-IR analysis, etc. The results indicated that the maximum doping stoichiometric content of tin was 0.5 in Fe3-xSnxO4. The substitution occurred prior to proceeding in the octahedral void between Sn4+ and Fe3+, because the ion radius of Sn4+ is very similar to Fe3+ and much smaller than Fe2+. In addition, the effects of tin content on the magnetic properties were revealed. The optimal coercivity value of 10.2 Oe was obtained for Fe2.9Sn0.1O4, which can be used as soft magnetic material. This is related to the lattice distortion caused by Sn4+.

Halogenation of Li7La3Zr2O12 solid electrolytes: a combined solid-state NMR, computational and electrochemical study

Tetragonal Li7La3Zr2O12 (LLZO) was halogenated to form cubic LLZOF(Cl) via a low temperature solid state synthetic route using PTFE and PVC polymers.

The magnetic properties dependence on temperature of Li-ferrite nanoparticle

The chemical formula Li0.5Fe2.5O4 of lithium ferrite prepared by two different chemical methods mentioned as low temperature solid state reaction (LTSSR) and modified combustion method (MCM). The samples showed nanoparticle scale with spinal structure. The magnetic analyses have done by the vibrating sample magnetometer VSM device, and both samples have the same magnetic properties represented by the magnetic saturation, remanence magnetization, and coercive magnetic field. The shape of hysteresis loop showed a soft ferrite and its area decreased with temperature increasing. On the other hand, the magnetic susceptibility decreased with increasing temperature for both samples of ferrite Li0.5Fe2.5O4 prepared. The sample of LTSSR exhibited a magnetic moment of about 0.410-3 JT-1 at applied magnetic field 50 kOe which is approaching the same for the sample prepared by MCM method.

Interfacial charge transfer complex between TiO2 and non-aromatic ligand squaric acid

The attachment of squaric acid, a non-aromatic molecule, to the surface of TiO2 powder induced the optical absorption of the obtained hybrid material in the visible spectral range due to the interfacial charge transfer complex formation. The optical characterization of the hybrid is supported by the density functional theory calculations of the model cluster. The paramagnetic species generated upon excitation with ultraviolet or visible light, in both TiO2 powders, pristine and surface-modified, were identified conducting low-temperature solid-state and indirect electron paramagnetic resonance (EPR) spectroscopy experiments (spin trapping and spin scavenging). The solid-state EPR experiments indicated the promotion of electrons from the organic moiety to the titania conduction band under visible-light excitation of hybrid. Also, the spin scavenging experiments showed that the electrons generated in the hybrid upon the visible-light activation facilitate the reduction of the radical cations present in the dispersion, while these effects are not observed for pristine TiO2.

Influence of rare earth substitution on structure, photoluminescence emission properties and Judd-Ofelt analysis of ZnS:Eu3+ red phosphors

A series of Eu3+ doped ZnS red emitting phosphors were synthesized by conventional low temperature solid state reaction technique. The structural and spectroscopic characteristics of the prepared materials were examined by theoretical and experimental methods. The XRD results confirm the formation of hexagonal structured ZnS material. Similar morphology is obtained from TEM and SEM analysis and the particle size and grain size were calculated. The compositional analysis using EDS confirms the atomic percentage present in the materials. The optical band gap energy of the samples varied from 3.59 to 3.43 eV. The PL emission under excitation 390 nm has greater emission intensity at concentration x = 0.1 in Zn(1-x)S: xEu3+ material. The intense red emission (614 nm) for concentration x = 0.1 have CIE coordinates (0.6090, 0.3905) with color purity 90.41% and CCT 1629.26 K. The site symmetry of Eu3+ ions was explained using PL emission spectra. The intensity parameters Ω2, Ω4 and Ω6, radiative properties like branching ratio (βR), transition radiative parameter (AR), stimulated emission cross section σe, radiative life time (τR) was calculated from Judd-Ofelt theory. The luminescence decay kinetics was analyzed and the life time of material was calculated in millisecond (ms) range. The strong and intense red emission and the improved stimulated emission cross section offer Eu3+ doped ZnS material useful for designing optoelectronic device applications.

Optimizing the time resolution of cryogenic calorimeters with NTDs: the CALIPSO project

The CALIPSO project deals with the development and optimization of low temperature (∼10 mK) solid state detectors. The goal of the project is to propose new strategies for improving the time resolution of cryogenic scintillating calorimeters, read with NTD thermistors. We will test new NTD-detector coupling techniques and optimize the NTD operation to make the response faster. In parallel, we will work on improving the scintillation light yield for different crystals at low temperatures. Rare events physics experiments utilizing the NTD-detector technology on a large scale, such as the ones searching for the neutrinoless double beta decay (CUORE, CUPID), could profit from the results of this project.

Efficient extraction of metals from thermally treated waste printed circuit boards using solid state chlorination: Statistical modeling and optimization

Formal recycling of e-waste is necessary for recovery of valuable metals and to avoid environmental damage due to use of toxic chemicals and illegal disposal of the leftovers. This study focused on development of an effective and environment-friendly method to extract valuable metals from waste printed circuit boards (WPCBs) using low temperature solid state chlorination followed by water leaching method. The shredded WPCBs were thermally pre-treated at 600 °C to convert plastic fraction into oil and combustible gases. The acquired metal rich residue (T-WPCBs) was chlorinated subsequently with NH4Cl. A combination of central composite design-response surface methodology (CCD-RSM) was successfully implemented into modeling the chlorination process for extraction of Au and Cu as a function of the process variables viz. temperature, time and NH4Cl dose. More than 96% of Cu and 67% of Au were extracted with water, when the T-WPCBs powder was chlorinated with 3 g/g of NH4Cl at 300 °C for 3 h. However, the proposed process has potential to extract other metals also; hence, the added credibility of the process was revealed by reporting extraction of other valuable metals such as Ni, Fe, Pb, Ag, and Zn at optimized conditions. This study strives to develop a closed loop process for extraction of metals; therefore, NH4Cl, the lone chemical used herein, was recycled for an economically viable process. Unlike the traditional pyrometallurgical process, which operates above 1000 °C and produces toxic fumes and soot, this process works at a low temperature range of 275–325 °C and able to extract out more than 90% of the total metal content without generating any toxic fume and soot.

Sn4P3-inlaid graphene oxide nanohybrid through low-temperature solid state reactions toward high-performance anode for sodium-ion batteries

Due to nature abundant and low-cost of sodium reserves with broad distribution in the earth's crust, sodium-ion batteries (SIBs) have attracted widespread attention for their great potential application in low-speed electric vehicles and large-scale energy storage system. However, their practical application is still hampered by the lack of decent anode materials. In this work, we develop an effective strategy to fabricate a nanohybrid of Sn4P3 and graphene oxide and demonstrate its outstanding sodium-storage behavior as an anode material for SIBs. By directly grinding tin(IV) chloride pentahydrate, sodium hydroxide, graphene oxide (GO) and surfactant PEG-200 at ambient temperature, an effective solid state reaction occurred to give rise to a precursor (named as SnO2/GO-PEG200), i.e. a nanocomposite of SnO2 encapsulated within GO matrix. After subsequent phosphorization at 280 °C using sodium hypophosphite monohydrate as phosphorous source, a nanohybrid of Sn4P3 and graphene oxide (designated as Sn4P3/GO-PEG200) was acquired. The coexistence of Sn4P3 nanoparticles and GO nanosheets endows the nanohybrid with improved electronic conductivity, highly structural integrity and superior electrochemical performance. When employed as anode material for SIBs, the nanohybrid anode demonstrates a good cycling stability (419 mA h g−1 after 100 cycles at 0.1 A g−1), with a remarkable rate capabilities (325 mA h g−1 at a current density of 1 A g−1 and 187 mA h g−1 at a current density of 5 A g−1, respectively).

Understanding the Interplay of Vacancy, Cation, and Charge Ordering in the Tunable Sc2VO5+δ Defect Fluorite System.

We report the synthesis, structure, and redox behavior of the cation-ordered tetragonal Sc2VO5+δ defect fluorite superstructure previously thought to be the oxygen precise A3+2B4+O5 phase. Four synthesis routes in oxidative, reductive, and inert atmospheres are demonstrated. Ex situ and in situ powder X-ray and neutron diffraction analyses reveal vanadium disproportionation reactions. The structure-reaction map illustrates the oxygen-dependent competition between the tetragonal cation and anion ordered Sc2VO5+δ and the disordered cubic Sc2VO5+δ' (δ < δ' ≤ 0.5) phases as a function of temperature. Oxidation states and oxide stoichiometries were determined with DC magnetometry and XANES experiments. The tetragonal cation ordered Sc2VO5+δ phase with δ = -0.15(2) for as-synthesized samples reveals vanadium charge ordering. V3+ and V4+ cations occupy octahedral sites, whereas V5+ predominantly occupies a tetrahedral site. The paramagnetic 8g{V3+/4+}4 clusters are isolated by diamagnetic 2cV5+ cations. At temperatures below 500 °C the 8g{V3+/4+}4 clusters can be topotactically fine-tuned with varying V3+/V4+ ratios. Above 600 °C the tetragonal structure oxidizes to the cubic Sc2VO5+δ' fluorite phase-its disordered competitor. The investigation of the cation- and anion-ordered Sc-V-O phases, their formation, and thermal stability is important for the design of low-temperature solid state oxide ion conductors and vacancy structures.

Millisecond Time-Resolved Solid-State NMR Reveals a Two-Stage Molecular Mechanism for Formation of Complexes between Calmodulin and a Target Peptide from Myosin Light Chain Kinase.

Calmodulin (CaM) mediates a wide range of biological responses to changes in intracellular Ca2+ concentrations through its calcium-dependent binding affinities to numerous target proteins. Binding of two Ca2+ ions to each of the two four-helix-bundle domains of CaM results in major conformational changes that create a potential binding site for the CaM binding domain of a target protein, which also undergoes major conformational changes to form the complex with CaM. Details of the molecular mechanism of complex formation are not well established, despite numerous structural, spectroscopic, thermodynamic, and kinetic studies. Here, we report a study of the process by which the 26-residue peptide M13, which represents the CaM binding domain of skeletal muscle myosin light chain kinase, forms a complex with CaM in the presence of excess Ca2+ on the millisecond time scale. Our experiments use a combination of selective 13C labeling of CaM and M13, rapid mixing of CaM solutions with M13/Ca2+ solutions, rapid freeze-quenching of the mixed solutions, and low-temperature solid state nuclear magnetic resonance (ssNMR) enhanced by dynamic nuclear polarization. From measurements of the dependence of 2D 13C-13C ssNMR spectra on the time between mixing and freezing, we find that the N-terminal portion of M13 converts from a conformationally disordered state to an α-helix and develops contacts with the C-terminal domain of CaM in about 2 ms. The C-terminal portion of M13 becomes α-helical and develops contacts with the N-terminal domain of CaM more slowly, in about 8 ms. The level of structural order in the CaM/M13/Ca2+ complexes, indicated by 13C ssNMR line widths, continues to increase beyond 27 ms.