A. B. Yaroslavtsev

Synthesis and properties of LiZr2(AsO4)3 and LiZr2(AsO4) x (PO4)3 − x

The LiZr2(AsO4)3 arsenate and LiZr2(AsO4)x(PO4)3 − x solid solutions have been prepared through precipitation followed by heat treatment, and characterized by X-ray diffraction, X-ray structure analysis, IR spectroscopy, and impedance spectroscopy. We have established conditions for the crystallization of the arsenate and a continuous series of arsenate phosphate solid solutions (0 ≤ x ≤ 3), which have been obtained as two polymorphs: monoclinic and hexagonal. Using the Rietveld method, we have refined the crystal structures of the polymorphs of LiZr2(AsO4)3 (sp. gr. P21/n, a = 9.1064(2), b = 9.1906(2), c = 12.7269(3) Å, β = 90.844(2)°, V =1065.03(5) Å3, Z = 4; sp. gr. R

Effect of ultrasonic processing on solid-state H+/Cs+ ion exchange in acid zirconium and tantalum phosphates

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Cation mobility in acid zirconium and tantalum phosphates and ion-exchange products (NaXH1−XTa(PO4)2·nH2O and NaYH2−YZr(PO4)2·nH2O)

c, a = 9.1600(4), c = 22.9059(13) Å, V = 1664.44(14) Å, Z = 6) and LiZr2(AsO4)1.5(PO4)1.5. Their structural frameworks are built up of AsO4 tetrahedra—or (As,P)O4 tetrahedra occupied by arsenic and phosphorus atoms at random—and ZrO6 octahedra, with the lithium atoms in between. The ionic conductivity of the materials has been measured. The cation conductivity of monoclinic LiZr2(AsO4)x(PO4)3 − x with 0 ≤ x ≤ 1 has been shown to exceed the conductivity of lithium zirconium phosphate.

Phase Transitions and Ion Conductivity in NASICON-typeCompounds Li_(1±X)Zr_(2-X)M_(X)(PO_4)_3, M = Ta, Nb, Y, Sc,In

The effect of ultrasonic processing on solid-state H+/Cs+ ion exchange in the HTa(PO4)2 · 2H2O–CsCl and Zr(HPO4)2 ·H2O–CsCl systems was studied. The rate of ion exchange was found to be substantially higher in the Ta system and to drop with increasing processing time in both systems. In addition, the ultrasonically initiated ion exchange raises the temperatures of subsequent dehydration and solid-state ion exchange in both systems.

Solid state reactions of alkali metal chlorides with acid tantalum phosphate, acid zirconium phosphate and vanadium oxyphosphate

Ion mobility has been investigated by impedance and 23 Na NMR relaxation measurements in the layered α-zirconium and tantalum phosphates and several of their sodium derivatives (Na Y H 2 YZr(PO4)2 nH 2 O and Na X H 1-X Ta(PO 4 ) 2 . nH 2 O). Sharp ion conductivity increase was detected for the small degrees of substitution in α-zirconium phosphate.

Proton conductivity of poly(arylene ether ketones) with different sulfonation degrees: Improvement via incorporation of nanodisperse zirconium acid phosphate

Ionic conductivity and phase transitions of lithium-zirconium phosphates, Li1±XZr2- XMX(PO4)3 (M = Ta, Nb, Y, Sc, In), with NASICON structure were studied using X-ray powder diffraction, calorimetry, 31P and 7Li NMR and impedance spectroscopy. Triclinic-rhombohedral phase transition in these materials occurs in a wide temperature range at coexistence of both phases. Unusual change of LiZr2(PO4)3 lattice parameters with temperature increase was found. During heating of this compound parameter “a” significantly decreases.

Ion DiffusionThrow Interface in Heterogeneous Solid Systems with the Modified Surface

Abstract Solid state reactions between HTa(PO4)2·2H2O, Zr(HPO4)2·H2O, VOPO4·2H2O and alkali metal chlorides have been studied. The coefficients of proton-alkali metal cation interdiffusion in the reaction products were determined. The increase of the cation radius leads to the growth of diffusion coefficients in HTa(PO4)2·2H2O–MCl and VOPO4·2H2O−MCl systems and their decrease in Zr(HPO4)2·H2O−MCl system. Estimated interdiffusion activation energies in HTa(PO4)2·2H2O were found to be 80, 50, 30 and 20 kJ/mol for Na, K, Rb, Cs and 120 and 240 kJ/mol for Na+ and K+ ions diffusion in Zr(HPO4)2·H2O. It was shown that alkali metal cation intercalation into phosphates matrix took place in the course of mechanical treatment. This leads to the dehydration temperature increase and to the decrease in solid state ion exchange process temperature. The mechanism of this process was proposed.

Synthesis of NASICON-Type Lithium Zirconium Phosphate

The proton conductivity of films based on sulfonated poly(arylene ether ketone) derived from bisphenol A and 4,4′-difluorobenzophenone of various modification degrees has been studied. The conductivity achieves high levels upon incorporation of a large amount of sulfo groups into the polymer. The conductivity of the samples with low sulfonation degrees may be increased via introduction of the nanodisperse zirconium acid sulfate additive.

Preparation and conductivity of the Keggin-type trivanadium-substituted tungstosilicic acid H7SiW9V3O40·9H2O

Information on ionic transport and defect formation processes at the interfaces of ionic crystals and other solid or liquid phases was discussed. Particular attention was paid to some new results in the field of ion transfer in heterogeneous solid sy stems with the surface modified by the thin films of new phase. Both problems: ion transport along and across the interface w ere xamined. All phenomena were discussed with the use of experimental data incl uding ion exchange kinetics and ion mobility in solids.