Defect perovskites in the SrO-ZrO2-Nb2O5 system
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Date
2006-02-07
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Australian Institute of Physics
Abstract
Compounds that can reversibly intercalate lithium have the potential to be used as
cathodes in rechargeable lithium ion batteries. Two characteristics, the availability of
interstitial or defect sites for the incorporation of lithium and the presence of reducible cations
are found in some defect perovskites. The aim of this study is to synthesise a number of defect
perovskites, which might be useful as host materials for Li intercalation, and investigate their
structures using X-ray and neutron powder diffraction.
The SrxNbO3, 0.7 ≤ x ≤ 1, solid solution having niobium in both oxidation states +IV
and +V whenever x < 1, has been reported to adopt the ideal cubic perovskite structure across
the whole solid solution field. Despite intensive searching when data were collected on good
quality single crystals no additional reflections were detected [1]. This indicates random
ordering between strontium and vacancies on the perovskite A sites.
Given the vacancies in the structure (particularly at the low strontium end of the solid
solution) and the accompanying presence of niobium +V, which can be easily reduced by
lithium metal, this solid solution appeared to be an interesting candidate to investigate Liintercalation
properties. Given that niobium +IV is not stable at high temperatures in air but
rather gets oxidised, previous syntheses of the solid solution were conducted in high vacuum.
Substitution of all niobium +IV by zirconium +IV allows syntheses to be carried out in air.
Since previous studies have shown that niobium and zirconium are able to occupy positions in
a structure at random [2-4], it was expected that a similar solid solution might be formed.
Therefore an investigation was undertaken in the SrO-ZrO2-Nb2O5 system to see whether an
analogous solid solution is indeed formed, what the extent of the solid solution range is and
whether this material has the potential to intercalate Li ions reversibly.
Description
Keywords
Perovskites, Defects, Lithium, Lithium ion batteries, Electric batteries, Clathrates, Crystals, Zirconium
Citation
Schmid, S., Elcombe, M., & Rhode, M. (2006). Defect perovskites in the SrO-ZrO2-Nb2O5 system. Paper presented to the 30th Annual Condensed Matter and Materials Meeting, Wagga Wagga, 7-10 February 2006. Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2006/cmm063.zip