From a 3D protonic conductor VO(H{sub 2}PO{sub 4}){sub 2} to a 2D cationic conductor Li{sub 4}VO(PO{sub 4}){sub 2} through lithium exchange
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 bd Marechal Juin, 14050 CAEN Cedex 4 (France)
- Department of Chemistry, University of Oslo, 0315 Oslo (Norway)
A new phase, Li{sub 4}VO(PO{sub 4}){sub 2} was synthesized by a lithium ion exchange reaction from protonic phase, VO(H{sub 2}PO{sub 4}){sub 2}. The structure was determined from neutron and synchrotron powder diffraction data. The exchange of lithium causes a stress, leading to a change in the dimensionality of the structure from 3D to 2D by the displacement of oxygen atoms. Thus, Li{sub 4}VO(PO{sub 4}){sub 2} crystallizes in P4/n space group with lattice parameters a=8.8204(1) A and c=8.7614(2) A. It consists of double layers [V{sub 2}P{sub 4}O{sub 18}]{sub {infinity}} formed by successive chains of VO{sub 6} octahedra and VO{sub 5} pyramids with isolated PO{sub 4} tetrahedra. The lithium ions located in between the layers promote mobility. Furthermore, the ionic conductivity of 10{sup -4} S/cm at 550 deg. C for Li{sub 4}VO(PO{sub 4}){sub 2} confirms the mobility of lithium ions in the layers. On the other hand, VO(H{sub 2}PO{sub 4}){sub 2} exhibits a conductivity of 10{sup -4} S/cm at room temperature due to the presence of protons in tunnels. - Graphical abstract: Li{sub 4}VO(PO{sub 4}){sub 2} was synthesized by a lithium ion exchange reaction from VO(H{sub 2}PO{sub 4}){sub 2}. The structure, determined from neutron and synchrotron powder diffraction data, changes in dimensionality from 3D to 2D. VO(H{sub 2}PO{sub 4}){sub 2} exhibits a protonic conductivity of 10{sup -4} S/cm at room temperature while Li{sub 4}VO(PO{sub 4}){sub 2} is a lithium conductor.
- OSTI ID:
- 21043825
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 9; Other Information: DOI: 10.1016/j.jssc.2007.06.019; PII: S0022-4596(07)00250-2; 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
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