A New Phase of the Na+ Ion Conductor Na3PS4

18 April 2019, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Solid electrolytes are crucial for next‑generation solid‑state batteries and Na3PS4 is one of the most promising Na+ conductors for such applications. At present, two phases of Na3PS4 have been identified and it had been thought to melt above 500 °C. In contrast, we show that it remains solid above this temperature and transforms into a third polymorph, γ, exhibiting superionic behavior. We propose an orthorhombic crystal structure for γ‑Na3PS4 based on scattering density analysis of diffraction data and density functional theory calculations. We show that the Na+ superionic behavior is associated with rotational motion of the thiophosphate polyanions pointing to a rotor phase, based on ab initio molecular dynamics simulations and supported by high‑temperature synchrotron and neutron diffraction, thermal analysis and impedance spectroscopy. These findings are of importance for the development of new polyanion‑based solid electrolytes.


Solid Electrolytes
Solid-State Batteries
All-solid-state batteries

Supplementary materials



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.