Studies on the System AIVMoO7-V2O5

The phase equilibria in the system AlVMoO₇-V₂O₅ were investigated over the whole component concentration range up to 1000°C. A phase diagram was constructed from the results of DTA and XRD methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Studium der Reaktionen von TlNO3-V2O5 in Fester Phase

The solid-state reactions of TlNO₃ with V₂O₅ in the molar ratios of 6∶5 and 2∶3 were studied by DTA, DTG and TG in the temperature ranges 20–550° and 20–400°, respectively, in a nitrogen atmosphere. For the molar ratio of 6∶5, thallium pentavanadate (Tl₃V₅O₁₄) was formed as the final product of reaction at 550°. The reaction proceeds stepwise, and Tl₂V₆O₁₆ and TlVO₃ were identified as intermediates. For the molar ratio of 2∶3, impure thallium hexavanadate (Tl₂V₆O₁₆) was obtained as the final product of reaction.

     

Electrical conductivity of g-Bi2O3-V2O5 solid solution

The total conductivity (σ_T) in bcc γ-Bi₂O₃ doped with V₂O₅ system has been measured in the composition range between 1 and 7 mol% V₂O₅ at different temperatures. Phase transitions for different addition amounts depending on the temperature were investigated by quenching the samples. According to the XRD and DTA/TG results, this bcc type solid solution was stable up to about 720°C and the solubility limit was found at ˜7 mol% V₂O₅ in γ-phase. This system showed predominantly an oxide ionic conduction. As the V₂O₅ addition increased, the ionic conduction increased up to 5 mol% V₂O₅ at which the highest conductivity was found to be 8.318·10^-2 Ω^-1 cm^-1 at 700°C and then decreased. It has been proposed that γ-Bi₂O₃ phase contains a large number of oxide anion vacancies and incorporated vanadium cations at tetrahedral sites which affect the oxygen sublattice of the crystal structure. This revised version was published online in August 2006 with corrections to the Cover Date.     

Phase formation in the Ag2O-ZnO (CdO)-V2O5 systems

The phase composition of the Ag₂O-ZnO(CdO)-V₂O₅ systems has been studied. Two new orthovanadates have been synthesized: AgZnVO₄ (monoclinic space group P21/n, a = 5.68710, b = 12.54080, c = 5.65947 Å, β = 116.209°) and AgCd₄(VO₄)₃ (orthorhombic space group Pnma, a = 9.82438 b = 7.01250, c = 5.37393 Å). One double metavanadate Ag₂Cd(VO₃)₄ has been synthesized. A continuous solid solution formulated as Ag_{3 ? 2x} Cd_{3 + x} (VO₄)₃ has been found to exist between AgCd₄(VO₄)₃ and already described AgCdVO₄. The Ag₂O-ZnO (CdO)-V₂O₅ systems have been triangulated in the subsolidus region.     

Improvement of lithium-ion conductivity in A-site-disordered lithium lanthanum titanates by V5+/Nb5+ substitution

The V⁵⁺/Nb⁵⁺-substituted lithium lanthaum titanates are synthesized by a conventional solid-state reaction method at high temperature in air. The structural and conductivity studies of the obtained perovskite oxide samples are investigated by x-ray diffraction (XRD), SEM, and impedance spectroscopy. From the powder XRD patterns, it is clearly observed that the synthesized samples exhibit a well-defined cubic structure with the Pm3m (Z = 1) space group. The lattice parameter is decreased with increasing vanadium content in Li_0.5?x La_0.5Ti_1?x V _x O₃, but increased with the increasing niobium content in Li_0.5?x La_0.5Ti_1?x Nb _x O₃. The scanning electron microscope measurements confirmed that these materials consist of fairly ordered grains throughout the surface area. The conductivity variations with the substitution of vanadium/niobium are also reported. The bulk ionic conductivity measured in the temperature range from room temperature to 150 °C is about the same as reported earlier for the related lithium lanthanum titanate. However, the low activation energies for ionic conduction observed for these samples encourage further investigations for better conductors in this system.     

Studies on the system Al2O3-V2O5-MoO3

Studies on the three-component system Al₂O₃-V₂O₅-MoO₃ have shown the existence of a new compound with molecular formula AlVMoO₇. The synthesis conditions and X-ray characteristics of this compound and its melting temperature, 690±10°C, are reported.

---

Zusammenfassung Einleitende Untersuchungen am Dreikomponentensystem Al₂O₃-V₂ O₅-MoO₃ zeigten die Existenz einer neuen, noch nicht publizierten Verbindung der Formel AlVMoO₇. Die Synthese der Verbindung sowie ihre röntgenographischen Eigenschaften wurden beschrieben. Ihr Schmelzpunkt beträgt 690±10°C.

     

Investigation of the thermal performance in lithium-ion cells during polyformaldehyde nail penetration

Journal of Thermal Analysis and Calorimetry - The nail penetration test on lithium-ion cells with a tungsten steel nail can cause significant heat sinking to the nail. In this work, a...     

LixV2O5 nanobelts for high capacity lithium-ion battery cathodes

5–10 μm long, typically 200–300 nm wide, and several nanometers thick Li_xV₂O₅ (× ～ 0.8) nanobelts with the δ-type crystal structure were synthesized by a hydrothermal treatment of Li⁺-exchanged V₂O₅ gel. When dried at 200 °C under vacuum prior to electrochemical testing, the as-prepared nanobelts underwent the well-known δ → ε → γ-phase transition giving a mixture of ε and γ phases as a nanocomposite electrode material. Such a simple preparation procedure guarantees a yield of material with drastically enhanced initial discharge specific capacity of 490 mAh/g and great cyclability. The enhanced electrochemical performance is attributed to the complex of experimental procedures including post-synthesis treatment of the single-crystalline Li_xV₂O₅ nanobelts.     

Studies on the Fe2(MoO4)3-V2O5 system

The phase equilibria established in solid state in the whole range of component concentrations in the Fe₂(MoO₄)₃-V₂O₅ system were studied by DTA and X-ray powder diffraction. This system is not a real two-component system.

---

Zusammenfassung Im gesamten Konzentrationsbereich der Komponenten des Systems Fe₂(MoO₄)₃-V₂O₅ wurde das im festen Aggregatzustand festgestellte Phasengleichgewicht mittels DTA und Pulverröntgendiffraktionsverfahren untersucht. Dieses System ist kein wirkliches Zweikomponentensystem.

---

F₂(₄)₃-V₂O₅ . , .

     

An investigation on electrochemical behavior of nanosize zinc sulfide electrode in lithium-ion cells

Nanosize zinc sulfides were synthesized through the chemical reaction method. The as-prepared zinc sulfide nanopowders were characterized by X-ray diffraction, transmission electron microscopy and electrochemical testing. The results revealed that zinc sulfide electrodes exhibited a reversible lithium storage capacity of about 400 mAh/g with stable cyclability. Zinc sulfide nanopowders show promise as anode materials for lithium-ion batteries.     

Uncovering the degradation mechanism induced by ion-diffusion kinetics in large-format lithium-ion pouch cells

Battery electrochemistry in an actual cell is a complicated behavior influenced by the current density,uniformity,and ion-diffusion distance,etc.The anisotropism of the lithiation/delithiation degree is usually inevitable,and even worse,due to a trend of big-size cell design,typically such as 4680 and blade cells,which accelerated a battery failure during repeat lithiation and delithiation of cathodes.Inspire by that,two big-size pouch cells with big sizes,herein,are selected to reveal the ion-d...     

A search for new phases in the system Fe2O3-V2O5-WO3

Studies on the three-component system Fe₂O₃-V₂O₅-WO₃ have shown the occurrence of a new, compound with molecular formula FeVW₂O₁₀. Its X-ray characteristics and its melting temperature, 865±10 °C, have been established.

---

Zusammenfassung Einleitende Untersuchungen am Dreikomponentensystem Fe₂O₃-V₂ O₅-WO₃ zeigten das Auftreten einer neuen, noch nicht publizierten Verbindung der Formel FeVW₂O₁₀. Die Verbindung wurde röntgenographisch beschrieben, ihr Schmelzpunkt beträgt 865 ±10°C.

     

IR-spectral investigation of the structure of glasses in the Fe2O3-V2O5 system

The structure of glasses in the Fe₂O₃-V₂O₅ system in the 0–50 mol% Fe₂O₃ range is studied by IR-spectroscopy. It is found that the introduction of Fe₂O₃ favours the transformation of the VO₅-groups into VO₄ ones. This effect may be shown with the aid of IR-spectra, owing to the fact that these glasses are characterized by two high-frequency bands at 1020 and 930 cm^–1. The first is determined by the vibrations of the short V=O nonbridging bonds in the VO₅-groups, while the second is assigned to the vibrations of the V—O-bonds in deformed VO₄-tetrahedra.

---

IR-spektroskopische Strukturuntersuchung von Gläsern des Systems Fe₂O₃-V₂O₅

Zusammenfassung Die Struktur von Gläsern des Systems Fe₂O₃-V₂O₅ in dem Bereich von 0–50 Molprozent Fe₂O₃ wurde mit Hilfe der IR-Spektroskopie untersucht. Zusatz von Fe₂O₃ begünstigt die Umwandlung der VO₅- in VO₄-Gruppen. Das kann in den IR-Spektren durch zwei Banden bei 1020 und 930 cm^–1 festgestellt werden. Die erste wird durch Schwingungen der kurzen V=O-Nichtbrücken-bindungen in den VO₅-Gruppen verursacht, die zweite wird auf Schwingungen der V—O-Bindungen in dem deformierten VO₄-Tetraeder zurückgeführt.

     

Investigation on the TeO2-MoO3-V2O5 System I. Phase Equilibrium

The phase equilibrium in the TeO₂-MoO₃-V₂O₅ system has been determined in air at atmospheric pressure. Differential thermal analysis (DTA), X-ray diffraction and optical microscopy were used for establishing the phase transitions. Two congruently melting ternary compounds (Te₃Mo₂V₂O₁₇ and TeMoV₂O₁₀) were identified by the above methods. Their fields of primary crystallization are entirely within the glass-formation range. The character and behaviour of the phases, the invariant points as well as the temperature maxima have been discussed. The glass-formation range correlates with the phase distribution in the system and includes all ternary invariant points.     

Studies on interactions in the NbBr5-Nb system

For studying the thermal disproportionation and interaction processes of niobium bromides in the NbBr₅-Nb system thermoanalytical and tensimetric methods were employed. The study revealed that the reduction of niobium pentabromide by metallic niobium starts at 257°C and leads to the formation of niobium tetrabromide. The temperature limits of the existence of bromides of niobium in lower oxidation states were determined.     

A novel method to solve the problem of distortion in commercial lithium-ion pouch cells

Journal of Solid State Electrochemistry - In this paper, a novel method to solve the problem of distortion in commercial lithium-ion pouch cells is introduced. The new approach mainly involves the...     

TiO2-V2O5纳米复合膜的制备及防腐蚀性能

采用溶胶-凝胶法和浸渍提拉技术在316L不锈钢表面构筑纳米TiO₂薄膜和“夹心”式TiO₂-V₂O₅复合薄膜（TiO₂/TiO₂-V₂O₅/TiO₂）, 应用AFM和XRD表征膜的形貌及纳米颗粒的晶型. 结合光、电化学方法测试了复合膜在0.5 mol•L^-1 NaCl溶液(pH=4.6)中暗态或紫外照射条件下的防腐蚀性能. 结果表明, TiO₂/TiO₂-V₂O₅/TiO₂复合膜具有双重保护功能, 即在紫外光照下可以起到光生阴极保护的作用, 特别是当停止光照后, 光生电位仍可维持在较低的电位长达6 h以上. 同时作为表面阻挡层, 可显著提高金属的耐腐蚀性.     

5'-Porphyrin-oligonucleotide conjugates: neutral porphyrin-DNA interactions

[chemical reaction: see text]. Incorporation of hydrophilic tetraarylporphyrin phosphoramidites into the 5'-termimus of the DNA as well as noncharged porphyrin-DNA interactions have been studied. Porphyrin-modified oligonucleotides show lower melting temperatures than their unmodified analogues. Single-stranded DNA interacts more strongly with porphyrin and causes more intense chiral disturbance in the porphyrin environment than the corresponding double strand.