Influence of Reduced Na Vacancy Concentrations in the Sodium Superionic Conductors Na11+ xSn2P1- xMxS12(M = Sn, Ge)

Marvin A. Kraft, Lara M. Gronych, Theodosios Famprikis, Wolfgang G. Zeier*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review


Exploration of sulfidic sodium solid electrolytes and their design contributes to advances in solid-state sodium batteries. Such a design is guided by a better understanding of fast sodium transport, for instance, in the herein studied Na11Sn2PS12-type materials. By using Rietveld refinements against synchrotron X-ray diffraction and electrochemical impedance spectroscopy, the influence of aliovalent substitution on the structure and transport in Na11+xSn2P1-xMxS12 with M = Ge and Sn is investigated. Although Sn induces stronger structural changes than Ge, the influence on the sodium sublattice and the ionic transport properties is comparable. Overall, a reduced in-grain activation energy of Na+ transport can be found with the reducing Na+ vacancy concentration. This work explores previously unreported phases in the Na11Sn2PS12 structure type based on their determined properties revealing Na+ vacancy concentrations to be an important factor providing a further understanding of Na11Sn2PS12-type materials.

Original languageEnglish
Pages (from-to)7250-7258
JournalACS Applied Energy Materials
Issue number7
Publication statusPublished - 2021

Bibliographical note

Accepted Author Manuscript


  • ion conduction
  • sodium solid electrolyte
  • solid-state battery
  • structure-transport relationships
  • vacancy concentration
  • X-ray diffraction


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