13568-40-6Relevant academic research and scientific papers
Electrical transport in the system Li2SO4-mLi2MoO4-2mLi3VO4
Lal,Gaur,Pathak
, p. 3683 - 3687 (1990)
The electrical conductivity (σ) and thermoelectric power (S) of three compounds (m = 0, 0.5 and 1) in the system Li2SO4-mLi2moO4-2mLi3 VO4 is reported from 500°C to the melting point. All three solids show a superionic phase just below their melting point. In this phase, σ decreases but activation energy and span of superionic phase increases for compounds with larger m. The phase transition temperature (Tp) from normal to superionic phase decreases with m. Below Tp, the order of σ is reversed. It increases with m but becomes mixed with the dominant ionic part.
Structure and properties of Li2–2xMg2+x(MoO4)3 crystals activated by copper ions
Ryadun,Trifonov,Nadolinny,Pavlyuk,Rakhmanova
, p. 459 - 463 (2016)
By the low-gradient ?zochralski method, both undoped and copper ion activated Li2–2xMg2+x(MoO4)3 crystals are grown. The charge state and structural position of impurity copper ions are determined using EPR. Investigations of the luminescence properties reveal that luminescence with a maximum at λ = 520 nm is observed for Li2–2xMg2+x(MoO4)3 crystals. A decrease in the temperature increases the intensity of this luminescence. It is found that the doping of Li2–2xMg2+x(MoO4)3 crystals with copper ions also increases the luminescence intensity with a maximum at λ = 520 nm. It is supposed that cation vacancies, which provide the charge compensation when copper ions substitute for lithium ions, are responsible for the luminescence.
Thermochemistry of lithium chromate Li2CrO4(cr) and lithium molybdate Li2MoO4(cr)
Shukla, N.K.,Prasad, R.,Roy, K.N.,Sood, D.D.
, p. 897 - 903 (1992)
The standard molar enthalpies of formation ΔfH degm at the temperature T = 298.15 K of Li2CrO4(cr) and Li2MoO4(cr) have been determined using an isoperibol solution calorimeter.The value of ΔsolHinfinite m for Li2CrO4(cr) in water at T = 298.15 K was found to be -(45.77 +/- 0.29) kJ * mol-1 and was used to obtain ΔfH degm(298.15 K) as -(1393.7 +/- 0.3)kJ * mol-1.The ΔsolH degm of Li2MoO4(cr) and of -3) at T = 298.15 K were used to obtain a value of -(1519.2 +/- 2.2)kJ * mol-1 for Δf H degm for Li2MoO4(cr).
Temperature induced phase transformations on the Li2MoO4 system studied by Raman spectroscopy
Saraiva,Paraguassu,Freire,Ramiro de Castro,de Sousa,Mendes Filho
, p. 119 - 124 (2017)
The present research reports results of lattice dynamics calculations and temperature-dependent Raman scattering study of the dilithium molybdate system, Li2MoO4, in the 25–600?°C temperature range. The effects of the temperature duly produced gradual changes, associated with the disorder and anharmonic effects followed by thermodynamic instability, leading the structure to a phase transformation. Calorimetric measurements up to 1000?°C corroborated that the crystal structure experienced gradual modifications, characterized by changes in the DSC base line. These stated thermal events as well as the changes in the profile of the Raman spectra, suggested that a phase transformation is connected with tilting and/or rotations of the MoO4 tetrahedron leading to a disorder in the MoO4 sites. The observation of one exothermic peak on the DSC curve at about 702?°C is related with the melting in the sample. The experimental results were discussed based on the mode assignments performed by using lattice dynamics calculations from where we predicted both wavenumbers and atomic displacements.
Synthesis and electrical properties of ternary molybdates Li 3Ba2R3(MoO4)8 (R = La-Lu, Y)
Kozhevnikova,Kopylova
, p. 384 - 387 (2011)
X-ray diffraction and differential-thermal analyses were used to study the phase relations in the subsolidus region of the system Li2MoO 4-BaMoO4-R2(MoO4)3. The temperature dependence of th
Electrochemical behavior of submicron Li2MoO3 as anodes in lithium-ion batteries
Li, Dan,He, Hongyan,Wu, Ximin,Li, Mingqi
, p. 759 - 765 (2016)
Theoretically, Li2MoO3 can serve as cathodes as well as anodes in lithium-ion batteries because Mo element in the compound is at the intermediate valence state. However, to date, little work has been devoted to the study of Li2MoO3 as anodes in lithium-ion batteries. In the paper, submicron Li2MoO3 is synthesized via simple liquid chemical reaction, followed by thermal reduction in H2/Ar (5:95 v/v) atmosphere. The as-prepared Li2MoO3 is polycrystalline with layered structure. At a current density of 100 mA g-1 over a voltage window of 0-3.0 V, the compound delivers a first discharge capacity of 836 mAh g-1 with a high initial coulombic efficiency of 94.5%. After 200 cycles at a current density of 300 mA g-1 over a voltage window of 0-3.0 V, a discharge capacity of 654 mAh g-1 is preserved. At a high current density of 1600 mA g-1, the composite still keeps a discharge capacity of 489 mAh g-1. The high first charge-discharge efficiency is ascribed to its self-compensation ability of Li2MoO3 for the first irreversible capacity loss.
Synthesis and X-ray diffraction and IR spectroscopy studies of ternary molybdates Li3Ba2R3(MoO4) 8 (R = La-Lu, Y)
Kozhevnikova,Kopylova
, p. 935 - 938 (2011)
Ternary molybdates Li3Ba2R3(MoO 4)8 (R = La-Lu, Y) were synthesized by the solid-phase method. Their unit cell parameters were determined and IR spectra were assigned. The compounds are isostructural
Electronic and ionic conduction in some simple lithium salts
Lal, H. B.,Gaur, Kanchan,Pathak, A. J.
, (1989)
The electrical conductivity (?) and thermoelectric power (S) of solidifed melt samples of Li2MoO4, Li2WO4 and Li2SO4 are presented in the temperature range 415 K to melting point of each compound. The ratio of ionic to electronic contribution to ? has been obtained with the help of a time-dependence study of dc electrical conductivity. It has been shown that the Li2MoO4 electronic contribution to ? remains high up to its melting point (about 8% just below the melting point) and it shows no superionic phase. However, in Li2WO4 and Li2SO4 a superionic phase is obtained in which the ionic contribution to ? is more than 99.99%. However, in normal ionic (or α) phase it is small and decreases with decreasing temperature. Separate temperature variations of ionic (?i) and electronic (?e) conductivities are presented and the conduction mechanisms are discussed. It is shown that ionic conduction in the β-phase is dominated by Schottky type defects.
Phase formation in Li2MoO4-K2MoO 4-MMoO4 (M = Ca, Pb, Ba) systems and the crystal structure of α-KLiMoO4
Gudkova,Solodovnikova,Solodovnikov,Zolotova,Kurat'Eva
, p. 1443 - 1452 (2011)
Solid-phase interactions in Li2MoO4-K 2MoO4-MMoO4 (M = Ca, Pb, Ba) systems were studied, and the subsolidus regions of these systems were triangulated. The lead and barium systems were studied in a more detailed way to discover that, along KLiMoO4-K2M(MoO4)2 (M = Pb, Ba), KLiMoO4-PbMoO4, and Li2MoO4-K 2Ba(MoO4)2 quasi-binary sections, there are homogeneity regions reaching 6-11 mol % based on K2M(MoO 4)2 and lead molybdate. Triple molybdates are formed in none of the systems, which is verified by experiments on spontaneous crystallization from solution in melt. Crystallization experiments yielded crystals of potassium dimolybdate and simple and double molybdates from the boundary systems. The crystal structure was solved for a hexagonal KLiMoO 4 phase: (Na,K){ZnPO4}, a = 18.8838(7) ?, c = 8.9911(6)?, Z = 24, space group P63, R = 0.065. The structure comprises a three-dimensional tridymite framework built by an alternation of corner-sharing LiO4- and MoO4 tetrahedra wherein voids are occupied by potassium cations.
Synthesis and luminescence properties of a Li3BaCaY3(MoO4)8:Er3+ phosphor with a layered scheelite-like structure
Kozhevnikova
, (2017)
A Li3BaCaY3(MoO4)8:Er3+ phosphor with a scheelite-like structure (sp. gr. C2/c) has been synthesized and its luminescence properties have been studied. The phosphor has been characterized by X-ray dif
