AgNa(VO2F2)2: A trioxovanadium fluoride with unconventional electrochemical properties

Martin D. Donakowski, Arno Görne, John T. Vaughey, Kenneth R. Poeppelmeier*

*Corresponding author for this work

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

We present structural and electrochemical analyses of a new double-wolframite compound: AgNa(VO2F2)2 or SSVOF. SSVOF is fully ordered and displays electrochemical characteristics that give insight into electrode design for energy storage beyond lithium-ion chemistries. The compound contains trioxovanadium fluoride octahedra that combine to form one-dimensional chain-like basic building units, characteristic of wolframite (NaWO4). The 1D chains are stacked to create 2D layers; the cations Ag+ and Na+ lie between these layers. The vanadium oxide-fluoride octahedra are ordered by the use of cations (Ag +, Na+) that differ in polarizability. In the case of sodium-ion batteries, thermodynamically, the use of a sodium anode introduces a 300 mV loss in overall cell voltage as compared to a lithium anode; however, this can be counter-balanced by introduction of fluoride into the framework to raise the reduction potentials via an inductive effect. This allows sodium-ion batteries to have comparable voltages to lithium systems. With SSVOF as a baseline compound, we have identified new materials design rules for emerging sodium-ion systems that do not apply to lithium-ion systems. These strategies can be applied broadly to provide materials of interest for fundamental structural chemistry and appreciable voltages for sodium-ion electrochemistry.

Original languageEnglish (US)
Pages (from-to)9898-9906
Number of pages9
JournalJournal of the American Chemical Society
Volume135
Issue number26
DOIs
StatePublished - Jul 3 2013

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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