Synthesis and structural study of a new NASICON-type solid solution: Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3}

Journal Article · Thu Mar 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.12.032· OSTI ID:21015741

Barre, M ^[1]; Le Berre, F ^[1]; Suard, E ^[2]; Fourquet, J L ^[1]

---

1. Laboratoire des Oxydes et Fluorures (UMR CNRS 6010), Institut de Recherche en Ingenierie Moleculaire et Materiaux Fonctionnels (FR CNRS 2575), Faculte des Sciences et Techniques, Universite du Maine, Av. O. Messiaen, 72085 Le Mans Cedex 9 (France)
2. Institut Laue-Langevin, 6 rue G. Horowitz, 38042 Grenoble Cedex 9 (France)

A new complete solid solution of NASICON-type compounds between LiZr{sub 2}(PO{sub 4}){sub 3} and La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} was evidenced with the general formula Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1). These phases were synthesized by a complex polymerizable method and structurally characterized from Rietveld treatment of their X-ray and neutron powder diffraction data. This solid solution results from the substitution mechanism Li{sup +{yields}}1/3La{sup 3+}+2/3{open_square} leading to an increase of the vacancies number correlated to an increase of the La content. According to this substitution mechanism, the general formula can then be written Li{sub 1-} {sub x} La {sub x} {sub /3}{open_square}{sub 2} {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1) in order to underline the correlation between the La content and the vacancies rate. For all the compounds, the structure is clearly related to that of the NASICON family with three crystallographic domains evidenced. For 0{<=}x{<=}0.5, all the members adopt at high temperature the typical NASICON-type structure (s.g. R3-barc), while at lower temperature, their structure distorts to a triclinic form (s.g. C 1-bar), as observed for LiZr{sub 2}(PO{sub 4}){sub 3} prepared above 1100 deg. C. Moreover, in this domain, the reversible transition is clearly soft and the transition temperature strongly depends of the x value. For 0.6{<=}x{<=}0.9, the compounds crystallize in a rhombohedral cell (s.g. R3-bar), while for x=1, the phase La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} is obtained (s.g. P3-bar, Z=6, a=8.7378(2) A, c=23.2156(7) A). This paper is devoted to the structure analysis of the series Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1), from X-ray and neutron powder thermo diffraction and transmission electron microscopy (TEM) studies. - Graphical abstract: Schematic drawing of the space group evolution at 800 deg. C in the solid solution Li{sub 1-} {sub x} La {sub x} {sub /3}Zr{sub 2}(PO{sub 4}){sub 3} (0{<=}x{<=}1)

• OSTI ID: 21015741
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 3; Other Information: DOI: 10.1016/j.jssc.2006.12.032; PII: S0022-4596(07)00011-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CRYSTALLOGRAPHY
LANTHANUM COMPOUNDS
LITHIUM COMPOUNDS
LITHIUM IONS
NEUTRON DIFFRACTION
SOLID SOLUTIONS
SPACE GROUPS
SYNTHESIS
TEMPERATURE RANGE 0400-1000 K
TRANSITION TEMPERATURE
TRANSMISSION ELECTRON MICROSCOPY
TRIGONAL LATTICES
VACANCIES
ZIRCONIUM PHOSPHATES