Abstract
On the road to highly performing solid electrolytes for solid state batteries, aliovalent substitution is a powerful strategy to improve the ionic conductivity. While the substitution allows optimization of the charge carrier concentration, effects on the local structure are often overlooked. Here, by pair distribution function analyses is shown that partial substitution of PS43− by SnS44− polyanion in the fast sodium ionic conductor Na11+xSn2+xP1−xS12 results in discrepancies between the local and average structure. The significantly larger SnS44− polyanions lead to inhomogeneities in the local environments of sodium ions and induce micro strain in the material. The combination of nuclear magnetic resonance spectroscopy and quasi-elastic neutron scattering reveals a decrease in the activation energy of fast local ionic jumps. The substitution widens the bottleneck size of some diffusion pathways, and a correlation between the increased strain and improved local ionic transport is observed. Local frustrations caused by the induced inhomogeneities may flatten the energy landscape and lead to the detected decrease in the activation barrier. Understanding these effects of cationic substitution on the local structure, induced crystallographic strain and ionic transport can open up new possibilities to design fast conducting solid electrolytes.
| Original language | English |
|---|---|
| Article number | 2500861 |
| Journal | Advanced Energy Materials |
| Volume | 15 |
| Issue number | 35 |
| DOIs | |
| State | Published - Sep 16 2025 |
Funding
Funded by the European Union (ERC, DIONISOS, 101123802). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. The research is supported by the International Graduate School for Battery Chemistry, Characterization, Analysis, Recycling and Application (BACCARA), which is funded by the Ministry for Culture and Science of North Rhine Westphalia, Germany. The authors acknowledge funding from the Deutsche Forschungsgemeinschaft under project number 459785385. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to BASIS on proposal number IPTS-30542. Funded by the European Union (ERC, DIONISOS, 101123802). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. The research is supported by the International Graduate School for Battery Chemistry, Characterization, Analysis, Recycling and Application (BACCARA), which is funded by the Ministry for Culture and Science of North Rhine Westphalia, Germany. The authors acknowledge funding from the Deutsche Forschungsgemeinschaft under project number 459785385. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to BASIS on proposal number IPTS‐30542.
Keywords
- ionic conductors
- local structure
- sodium ion
- strain