I. Yu. Pinus

Kinetics of lithium deintercalation from LiFePO 4

We have studied the kinetics of lithium deintercalation from lithium iron phosphate in a cathode material for batteries. The main contribution to the resistance of the cell is made by interfaces and the resistance of LiFePO4 grains. The FePO4 solubility in LiFePO4 is 4.0%. The lithium deintercalation process can be described in terms of a heterogeneous grain model and its rate is controlled by the lithium diffusion across the layer of the forming product (FePO4).

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

Low-temperature heat capacity and thermal behavior of Zn0.98Co0.02O in the high-temperature region

\bar 3

Synthesis and properties of AgTi2(PO4)3-based NASICON-type phosphates doped with Nb5+, Zr4+, and Ga3+

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.

Thermodynamic characteristics of polyheteroarylene blends

The low-temperature heat capacity of Zn 0.98Co0.02O oxide was measured by adiabatic calorimetry. The formation of a solid solution was shown to be accompanied by a change in the entropy by 0.4 J/(K mol). No anomalies in the heat capacity or the thermal behavior confirming the phase transformations found earlier by other methods were observed. A heat capacity anomaly was revealed below 15 K and tentatively attributed to a change in the magnetic properties of the substance.

Cation mobility in modified Li1 − xTi2 − xNbx(PO4)3 lithium titanium NASICON phosphates

We have synthesized materials based on a silver titanium phosphate with partial substitution of tri-, tetra-, or pentavalent cations for titanium: Ag1±xTi2−xMx(PO4)3 (M = Nb5+, Ga3+) and AgTi2−xZrx(PO4)3. The materials have been characterized by X-ray diffraction and impedance spectroscopy and have been shown to have small thermal expansion coefficients. Their ionic conductivity has been determined. Silver ions in these materials are difficult to replace with protons.

Phase transitions of the NASICON-type mixed phosphates LiM2(PO4)3 (M = Ti, Zr) and LiInNb(PO4)3

The influence of the polybenzimidazole-to-polybismaleimide ratios and the chemical nature of sorbates on the thermodynamic characteristics of thermally structured blends of the polymers is studied. The optimum component ratio for the production of blends with good mechanical properties is found. The proton conductivity of the blends doped with phosphoric acid and acid zirconium phosphate is investigated.

Solid composite electrolytes based on zirconium hydrogen phosphate and polyaniline

Li1 − xTi2 − xNbx(PO4)3 NASICON materials are prepared and studied by X-ray diffraction, 7Li and 31P NMR spectroscopy, and impedance spectroscopy. Vacancy mobility in Li1 − xTi2 − xNbx(PO4)3 is lower than interstitial lithium mobility. Nb5+ cations with low doping levels increase cation mobility in LiTi2(PO4)3.

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 structural phase transitions of LiTi2(PO4)3, LiInNb(PO4)3, and LiZr2(PO4)3 have been studied by X-ray diffraction, impedance spectroscopy, 7Li NMR spectroscopy, and calorimetry. The results indicate that, as the temperature is raised, the lithium ions in the structure of LiTi2(PO4)3 and LiInNb(PO4)3 redistribute between the M1 and M2 sites. The thermal expansion coefficients along the crystallographic axes of LiTi2(PO4)3 and LiInNb(PO4)3 are estimated.

Effect of ultrasonication on the formation and properties of zirconium hydrogen phosphate HZr2(PO4)3 · nH2O with NASICON structure

The interaction in the zirconium hydrogen phosphate-polyaniline (PAN) system is studied using impedance and IR spectroscopy. Strong hydrogen bonds N-H...O and O-H...N are formed at the interface in this system. An appreciable increase in the ionic conductivity of composite materials based on zirconium hydrogen phosphate and PAN is discovered.