Abstract
This paper reports on the results of experimental investigations of solid solutions that have a ramsdellite structure and crystallize in the Li2O-Fe2O3-SnO2-TiO2, Li2O-Fe2O3-TiO2, and Li2O-Cr2O3-TiO2 systems. The concentration boundaries of existence of these solid solutions are determined, and their thermal and electrical properties are studied. It is established that the ramsdellite phases crystallizing in the Li2O-Fe2O3-SnO2-TiO2 and Li2O-Fe2O3-TiO2 systems transform into a metastable hexagonal phase at temperatures of ∼ 650–700 and 550°C, respectively. The results of investigations of this phase transformation by differential thermal analysis, differential scanning calorimetry, and high-temperature X-ray diffraction, as well as measurements of the electrical conductivity of the ramsdellite phases in the Li2O-Fe2O3-SnO2-TiO2 system, indicate that this transition is a first-order phase transition. Solid solutions of ramsdellite phases crystallizing in the Li2O-Cr2O3-TiO2 system do not undergo the phase transformation under consideration. These solid solutions are stable during multiple dynamic heating to 1000°C (under heating-cooling conditions at a rate of 10–15°C/min). Long-term heat treatments at 1000°C (for more than 3 h) lead to their decomposition with the formation of ramsdellite phases of the unknown composition and the Li2TiO3 compound. The electrical conductivities of the solid solutions formed by the ramsdellite phases crystallizing in the Li2O-Fe2O3-TiO2 and Li2O-Cr2O3-TiO2 systems at a temperature of 500°C are evaluated to be σ ≈ 10−1.5 S/cm. The transformation of the ramsdellite phases in the Li2O-Fe2O3-TiO2 system into the metastable hexagonal phases is accompanied by a decrease in the electrical conductivity by several orders of magnitude. The electrical conductivity of Li1.9Cr x Ti3.025 − 0.75x O7 (0 ≤ x ≤ 0.8) solid solutions remains unchanged upon multiple dynamic heating to 1000°C (with subsequent cooling).
Similar content being viewed by others
References
Kolotyrkin, V.I., Metlin, Yu.G., and Tret’yakov, Yu.D., Lithium Titanate with a Ramsdellite Structure as a Cationic Conductor in Reversible Galvanic Circuits, Vest. Mosk. Gos. Univ., Ser. 2: Khim., 1978, vol. 19, no. 5, pp. 595–599.
Boyce, J.B. and Mikkelsen, J.C., Jr., Anisotropic Conductivity in a Channel Structured Superionic Conductors: Li2Ti3O7, Solid State Commun., 1979, vol. 31, no. 10, pp. 741–745.
Lacorre, Ph., Hervieu, M., Choisnet, J., and Raveau, B., Oxydes M 3O4 à empilement hexagonal double type D.H. LiFeSnO4 (M = Li, Fe, Sn, Sb): Transitions réversibles ramsdellite-D.H. LiFeSnO4, J. Solid State Chem., 1984, vol. 51, no. 1, pp. 44–52.
Grigor’eva, L.F., Petrov, S.A., Sinel’shchikova, O.Yu., and Gusarov, V.V., Design of New Functional Materials Based on Complex Oxides with a Tunnel Structure of the Ramsdellite, Hollandite, and Ba2Ti9O20 Types, Fiz. Khim. Stekla, 2004, vol. 30, no. 3, pp. 346–361 [Glass Phys. Chem. (Engl. transl.), 2004, vol. 30, no. 3, pp. 257–269].
Chen, C.J. and Greenblatt, M., Lithium Insertion into Li2Ti3O7, Mater. Res. Bull., 1985, vol. 20, pp. 1347–1352.
Petrov, S.A., Sinel’shchikova, O.Yu., Grigor’eva, L.F., Patrina, I.B., Ovchinnikov, N.O., and Gusarov, V.V., Synthesis of Titanates with a Ramsdellite-Type Tunnel Structure Crystallizing in the Li2O-Fe2O3-TiO2 System in Different Gaseous Media, Fiz. Khim. Stekla, 2005, vol. 31, no. 6, pp. 1106–1111 [Glass Phys. Chem. (Engl. transl.), 2005, vol. 31, no. 6, pp. 803–807].
Shannon, R.D. and Prewitt, C.T., Effective Ionic Radii in Oxides and Fluorides, Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem., 1969, vol. 25, no. 5, pp. 925–946.
Lacorre, Ph., Hervieu, M., Pannetier, J., Choisnet, J., and Raveau, B., Neutron Diffraction Study of Li1+x (Li2x/3Fe1 − x Sn1 + x/3)O8, a Nonstoichiometric Ramsdellite and Its Transition to a Double Hexagonal Close Packed Structure for x = 0, J. Solid State Chem., 1983, vol. 50, no. 2, pp. 196–203.
Choisnet, J., Hervieu, M., Raveau, B., et al., Two Polymorphous Lithium Stannoferrites LiFeSnO4: A Ramsdellite-Type and Hexagonal Close-Packed Structure, J. Solid State Chem., 1981, vol. 40, no. 3, pp. 344–351.
Pyatenko, Yu.A., Voronkov, A.A., and Pudovkina, Z.V., Mineralogicheskaya kristallokhimiya titana (Mineralogical Crystal Chemistry), Moscow: Nauka, 1976 [in Russian].
Petrov, S.A., Filatov, S.K., Grigor’eva, L.F., and Kostyreva, T.G., Thermal Transformations and Distortions of Ramsdellite-Type Phases in the LiFeO2-SnO2-TiO2 System, Izv. Akad. Nauk SSSR, Neorg. Mater., 1992, vol. 28, no. 5, pp. 1070–1076.
Petrov, S.A., Grigor’eva, L.F., Filatov, S.K., Sazeev, I.Yu., and Kostyreva, T.G., Effect of Chemical Composition of Ramsdellite-Type Phases Crystallizing in the LiFeO2-SnO2-TiO2 System on Their Structure, Electrical Properties, and Phase Transformations upon Heating, Zh. Prikl. Khim. (St. Petersburg), 1992, vol. 65, no. 1, pp. 16–22.
Izquierdo, G. and West, A.R., Phase Equilibria in the System Li2O-TiO2, Mater. Res. Bull., 1980, vol. 15, no. 11, pp. 1655–1661.
Mikkelsen, J.C., Pseudobinary Phase Relations of Li2Ti3O7, J. Am. Ceram. Soc., 1980, vol. 63, nos. 5–6, pp. 331–335.
Author information
Authors and Affiliations
Additional information
Original Russian Text © S.A. Petrov, L.F. Grigor’eva, O.Yu. Sinel’shchikova, V.V. Gusarov, 2008, published in Fizika i Khimiya Stekla.
Rights and permissions
About this article
Cite this article
Petrov, S.A., Grigor’eva, L.F., Sinel’shchikova, O.Y. et al. Physicochemical prerequisites of the synthesis of new ionic conductors based on complex oxides with a ramsdellite-type structure. Glass Phys Chem 34, 449–460 (2008). https://doi.org/10.1134/S1087659608040123
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1087659608040123