Synthesis, Crystal Structure, and Properties of the Alluaudite-Type Vanadates Ag2-xNaxMn2Fe(VO4)3

Hamdi Yahia, Masahiro Shikano, Mitsuharu Tabuchi, Ilias Belharouak

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11 Citations (Scopus)

Abstract

The new members of the Ag2-xNaxMn2Fe(VO4)3 (0 ≤ x ≤ 2) solid solution were synthesized by a solid-state reaction route, and their crystal structures were determined from single-crystal X-ray diffraction data. The physical properties were characterized by Mössbauer and electrochemical impedance spectroscopies, galvanostatic cycling, and cyclic voltammetry. These materials crystallize with a monoclinic symmetry (space group C2/c), and the structure is considered to be a new member of the AA′MM′2(XO4)3 alluaudite family. The A, A′, M, and X sites are fully occupied by Ag+/Na+, Ag+/Na+, Mn2+, and V5+, respectively, whereas a Mn2+/Fe3+ mixture is observed in the M′ site. The Mössbauer spectra confirm that iron is trivalent. The impedance measurements indicate that the silver phase is a better conductor than the sodium phase. Furthermore, these phases exhibit ionic conductivities 2 orders of magnitude higher than those of the homologous phosphates. The electrochemical tests prove that Na2Mn2Fe(VO4)3 is active as positive and negative electrodes in sodium-ion batteries.

Original languageEnglish
Pages (from-to)4643-4649
Number of pages7
JournalInorganic Chemistry
Volume55
Issue number9
DOIs
Publication statusPublished - 2 May 2016

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ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry

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