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

13 May 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Exploration of sulfidic sodium solid electrolytes and their design contributes to advances in solid state sodium batteries. Such 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 onto the structure and transport in Na11+xSn2P1−xMxS12 with M = Ge and Sn is investigated. Whereas Sn induces stronger structural changes than Ge, the found influence on the sodium sublattice and the ionic transport properties are 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 that, based on their determined properties reveal Na+ vacancy concentrations to be an important factor guiding further understanding within Na11Sn2PS12-type materials.


Solid ionic conductors
Ionic transport
Na solid electrolytes

Supplementary materials

Supporting Information


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.