Composite electrode materials based on LiFeBO3 are synthesized under different conditions and studied as the cathodic materials for lithiumion batteries. Composites with different degrees of iron oxidation are synthesized by annealing in a closed system with the use of metal-oxide getters. Based on the results of cyclic voltammetry and galvanostatic cycling of samples with different Fe(II) contents, it is concluded that the surface composition is the determining factor for applicability of materials to reversible processes of inter-calation-deintercalation.

Samples of a LiMn 1− x Zn x BO 3 ( x = 0, 0.1, 0.15, 0.3) solid solution were synthesized for the first time and characterized. The modification of complex borate with the hexagonal or monoclinic unit cell symmetry is formed depending on the x value. The hexagonal phase has a narrow homogeneity range near x = 0 according to the X-ray powder diffraction data. The monoclinic form is characterized by a broader range of compositions with x = 0.15 and x = 0.3 inside. No ordering of manganese and zinc cations was observed in the whole studied composition range. The lithium diffusion coefficients were calculated by the molecular dynamics simulation for the both modifications of LiMnBO 3 and LiMn 0.85 Zn 0.15 BO 3 solid solution.

Sodium ruthenium(III,IV) oxide Na1−x Ru2O4 was synthesized by the solid state reaction of Na2CO3 and RuO2 in inert atmosphere and characterized by X-ray powder diffraction, electron diffraction, and high-resolution transmission electron microscopy. The compound crystallizes in the CaFe2O4-type structure (space group Pnma, Z = 4, a = 9.2641(7) Å, b = 2.8249(3) Å, c = 11.1496(7) Å). Double rutile-like chains of the RuO6 octahedra form a three-dimensional framework, whose tunnels contain sodium cations. The structure contains two crystallographically independent sites of ruthenium atoms randomly occupied by the RuIII and RuIV cations. The superstructure with the doubled b parameter found for one of the samples under study using electron diffraction is caused, probably, by ordering of the Ru cations in the rutile-like chains. The Na1− x Ru2O4 compound exhibits temperature-independent paramagnetism with χ0 = 1.9·10−4 cm3 (mole of Ru−1).

Lead vanadium phosphate Pb3V(PO4)3 was synthesized by solid state reaction and characterized by X-ray single crystal and powder diffraction, electron microscopy, and magnetic susceptibility measurements. The crystal structure model of Pb3V(PO4)3 was refined using X-ray single crystal data (a=10.127(1)Å, S.G. I4¯3d, Z=4). The compound has an eulytite-like structure and its average structure model may be presented as a three-dimensional network formed by strongly distorted mixed (Pb/VIII) metal-oxygen octahedra connected by edge sharing and forming corrugated chains. The octahedra are additionally linked by tetrahedral phosphate groups via corner sharing. Lead and vanadium atoms randomly occupy two close positions in the octahedra. The electron microscopy study revealed the presence of a rhombohedral superstructure with asup=asub×2 and csup=csub×75/2 indicating ordering in the structure. The same type of superstructure was found by us for two another lead-containing eulytite Pb3Fe(PO4)3 where Fe+3 has an ionic radius close to that of V+3. Magnetic susceptibility measurements revealed Curie–Weiss behavior for the Pb3V(PO4)3 compound.

The new vanadyl phosphate Na4VO(PO4)(2) was synthesized and investigated by X-ray powder and single-crystal diffraction, high-temperature X-ray diffraction, electron diffraction, high-resolution electron microscopy, thermal analysis, magnetic susceptibility, and conductivity measurements. The compound undergoes a reversible phase transition at about 200 degreesC. The crystal structure of low-temperature beta-Na4VO(PO4)(2) was solved using X-ray single-crystal data. This phase has an orthorhombic unit cell with lattice parameters a = 16.0068(12) Angstrom, b = 14.5129(8) Angstrom, c = 7.0231(5) Angstrom, S.G. Pbca, and Z = 8. The crystal structure of beta-Na4-VO(PO4)(2) is built by isolated chains formed by corner-shared V4+O6 octahedra linked additionally via corners by two PO4 tetrahedra. All chains in the structure are equivalent. Na cations are located between the chains in an ordered manner. High-temperature alpha-Na4VO(PO4)(2) also has.an orthorhombic cell with lattice parameters a = 15.595(l) Angstrom, b = 14.651(2) Angstrom, c = 7.0262(6) Angstrom, S.G. Ibam, and Z = 8. Electron diffraction study revealed an existence of various structural transformations occurring in situ in the transmission electron microscope. In both alpha- and beta-modifications, the susceptibility follows a Curie-Weiss law with a very small Curie-Weiss temperature, indicating a very weak magnetic exchange among the V4+ ions.